Influence and significance of angle Kappa on total ocular aberrations before and after SMILE surgery / 中华实验眼科杂志

Objective:To investigate the influence of angle Kappa on total high-order aberration (HOA) before and after small incision lenticule extraction (SMILE).Methods:An observational case series study was conducted.Right eyes of 98 patients with myopia and myopic astigmatism who underwent SMILE surgery at Tianjin Eye Hospital from April 2015 to May 2016 were selected.Uncorrected visual acuity (UCVA), spherical diopter and cylindrical diopter under cycloplegic condition were examined before the surgery and at l and 3 months postoperatively.The chord distance of angle Kappa was measured by Pentacam topography.Wavefront aberrations were measured by WaveScan aberrometer.Pre- and postoperative UCVA, refractive status and each HOA were analyzed.The relationship between angle Kappa and each HOA was analyzed by Pearson correlation.This study adhered to the Declaration of Helsinki.The study protocol was approved by an Ethics Committee of Tianjin Eye Hospital (No.TJYYLL-2017-17). Written informed consent was obtained from each subject.Results:The preoperative, postoperative 1-month and postoperative 3-month UCVA (LogMAR) were 0.06±0.23, -0.03±0.07 and -0.05±0.07, respectively, showing a statistically significant difference ( F=779.330, P<0.001). There were statistically significant differences in spherical diopter, cylinder diopter and spherical equivalent (SE) between before and after operation ( F=1 107.811, 127.786, 1 191.266; all at P<0.001), and the postoperative spherical diopter, cylinder diopter and SE were significantly lower than those before surgery (all at P<0.001). At 6-mm pupil diameter, significant differences were found between postoperative total HOA, spherical aberration, coma, the third-order aberration (S3), fourth-order aberration (S4), fifth-order aberration (S5) and sixth-order aberration (S6) and the preoperative values ( F=75.915, 78.231, 66.186, 64.521, 97.161, 36.623, 28.852; all at P<0.001). The postoperative 1- and 3-month total HOA, spherical aberration, coma, S3, S4, S5 and S6 were significantly increased in comparison with those before surgery (all at P<0.05). There was a positive correlation between angle Kappa and total HOA, coma and S3 at 1 and 3 months after surgery (total HOA: r=0.357, 0.363; both at P<0.001.coma: r=0.310, 0.341; both at P<0.01.S3∶ r=0.343, 0.371; both at P<0.01). Significant differences were found in preoperative, postoperative 1-month and 3-month total HOA, coma and S3 between groups with different angle Kappa ( Fgroup=3.363, 4.277, 4.029; all at P<0.05). The postoperative total HOA, coma and S3 of the larger angle Kappa group were greater than those of the smaller angle Kappa group, with statistically significant differences between them (all at P<0.05). Conclusions:A larger angle Kappa may induce HOAs in SMILE surgery.

Lentes intraoculares fácicas para miopia e astigmatismo: revisão prospectiva / Phakic intraocular lenses for myopia and astigmatism: a prospective review

RESUMO O implante de lentes intraoculares fácicas com finalidade refrativa é uma alternativa cirúrgica eletiva segura e eficiente. Essa opção deve ser considerada de forma eletiva para tratar ametropias, nos casos em que as cirurgias de correção visual refrativa a laser na córnea apresentam maior risco de complicações, seja por características da córnea ou pela magnitude da ametropia. Este artigo traz uma revisão prospectiva das lentes fácicas disponíveis no mercado brasileiro em 2020 e suas características.

ABSTRACT Implantation of phakic intraocular lenses for refractive purpose is a safe and efficient elective surgical alternative. This option should be considered to electively treat ametropia when laser corneal refractive surgery has higher risk of complications, either due to corneal characteristics or the magnitude of ametropia. This article provides a prospective review of the phakic lenses available in the Brazilian market in 2020 and their characteristics.

Clinical evaluation of LASEK for residual myopia following phakic posterior chamber implantable contact lens implantation in extreme high myopic eyes / 中华实验眼科杂志

Background Phakic posterior chamber implantable contact lens (PPC-ICL) or phakic posterior chamber Toric implantable contact lens (PPC-TICL) implantation is an effective way for the correction of high myopia or high myopia with astigmia,but it often has residual myopic power.Excimer laser-assisted subepithelial keratectomy (LASEK) can correct the residual myopia following PPC-ICL or PPC-TICL,but its effectiveness and safety deserve attention.Objective This study was to analyze the clinical effectiveness and safety of LASEK for residual myopia after PPC-ICL implantation for extreme high myopia.Methods A prospective cases-observational study was performed,and written informed consent was obtained from each patient before any surgery.Fourteen eyes of 9 patients with residual myopia following PPC-ICL or PPC-TICL for the eyes with spherical equivalent refraction of ≥-20.00 D were collected in the Affiliated Hospital of Guizhou Medical University from July 2010 to March 2015,including PPCICL implantation in 8 eyes and PPC-TICL implantation in 6 eyes.LASEK were performed on the eyes to correct the residual myopic power.Uncorrected visual acuity (UCVA),best corrected visual acuity (BCVA),haze,the distance of intraocular lens to lens,corneal thickness,corneal topography,corneal endothelial cell counting,intraocular pressure (IOP) and fundus were examined and compared before and after surgery.The effectiveness and safety of the surgery were evaluated.Results The operation was smooth and no complication was found after surgery in all of the eyes.The UCVA and BCVA were significantly different in the eyes among before surgery,6 months after PPC-ICL implantation and 12 months after LASEK (F =31.360,1.778;both at P＜0.05),and the UCVA after LASEK was higher than BCVA before LASEK.The refractive powers were (-22.27-±4.29),(-3.75±2.25) and (-0.42±0.63) D before surgery,6 months after PPC-ICL implantation and 12 months after LASEK,showing a significant difference among them (F=46.370,P＜0.05),and the refractive power was considerably lower after LASEK than that before surgery and after PPC-ICL implantation (both at P＜0.05).No significant difference was found in IOP or corneal endothelial cell counting in operated eyes among before surgery,6 months after PPC-ICL implantation and 12 months after LASEK (F=1.663,1.055;both at P＞0.05).The distance of intraocular lens to lens was (0.69±0.26)mm in the eyes after LASEK and (0.71 ±0.29)mm in the eyes after PPC-ICL implantation,with no significant difference between them (t =0.192,P＞0.05).Conclusions PPC-ICL or PPC-TICL implantation for the correction extreme high myopia often remains a certain degree of myopia,and LASEK for the correction of residual refractive power is safe and effective.

Comparison of corneal ablation depth predictability between small incision lenticule extraction and femtosecond laser-assisted in situ keratomileusis for myopia / 中华实验眼科杂志

Background Recently,small incision lenticule extraction (SMILE) procedure is used to correct myopia.The clinical safety and efficiency of SMILE have been approved,but its predictability to corneal ablation depth is brought into focus.Objective This study was to compare the predictability of ablation depth in central cornea between SMILE and femtosecond laser-assisted in situ keratomileusis (FS-LASIK) for myopia.Methods A nonrandomized controlled clinical study was performed.Two hundred and seventy eyes of 135 myopic patients who were going to receive corneal refractive surgery were included in Beijing Tongren Hospital from October 2015 to May 2016.SMILE and FS-LASIK were performed on 138 eyes of 69 patients and 132 eyes of 66 patients matched in demography respectively under the informed consent.Central corneal thickness was measured by RTVue FD-OCT before and 1 week after surgery.The refractive power,actual ablation depth (difference of central corneal thickness before and after surgery) and central corneal cutting error (difference between theoretically expected ablation depth and real ablation depth) were intergrouply compared,and the correlation of real ablation depth with theoretically expected ablation depth was assessed.Results No significant difference was found in spherical power,astigmatic power and spherical equivalent after surgery between SMILE group and FS-LASIK group (t =-1.826,-1.405,-1.420,all at P＞0.05).The actual ablation depth was (76.96± 15.27)μm in the SMILE group,which was significant lower than (96.76± 16.52) μm of theoretically expected ablation depth (t =-23.016,P ＜ 0.01);however,there was no significant difference in the FS-LASIK group between actual and expected ablation depth ([77.92 ± 18.69] μm versus [77.42± 15.60] μm) (t =-0.604,P =0.547).The central corneal cutting error was (20.55 ± 8.51) μm in the SMILE group and (7.17±5.97) μm in the FS-LASIK group,showing a significant difference between them (t=14.950,P＜0.01).The positive linear correlations were seen between actual and expected ablation depth in both SMILE group and FS-LASIK group (r=0.799,0.867,both at P＜0.01).The actual ablation depth was increased over expected ablation depth,with the regression equations of Y=3.892+0.749X in the SMILE group and Y=3.443 + 0.957X in the FS-LASIK group.Conclusions The actual corneal ablation depth is less than expected corneal ablation depth in SMILE procedure,while in FS-LASIK procedure,the actual corneal ablation depth appears to be consistent with the expected one,inferring a good predictability in corneal ablation depth in FS-LASIK surgery.

A comparative study of visual quality between implantable collamer lens implantation and femtosecond LASIK for myopia / 中华实验眼科杂志

Background The incidence of myopia is gradually increasing,and how to choose a better corrective method of myopia for the best visual demand is very important.Objective This study was to compare visual quality of implantable collamer lens (ICL) implantation with femtosecond laser in situ keratomileusis (FSLASIK) for moderate and high myopia using double-pass optical quality analysis system (OQAS).Methods A non-randomized controlled clinical trail was performed.Fifty-two eyes with-4.00 to-9.00 D of 26 consecutive patients were included in NO.1 Hospital of Xi'an from January 2015 to January 2016.Twenty-four eyes of 12 patients with the corneal thickness ＜500 μm received ICL implantation as ICL group and 28 eyes of 14 patients which corneal thickness was ≥500 μm underwent FS-LASIK surgery as FS-LASIK group.The demography was matched between the two groups (all at P＞0.05).All the patients were followed-up for 3 months after surgery.The preoperative best corrected distance visual acuity (BCDVA),spherical equivalent (SE),postoperative uncorrected distance visual acuity (UCDVA),BCDVA and SE were examined and compared between two groups.The parameters from OQAS were evaluated and intergrouply compared,including the objective scattering inders (OSI),modulation transfer function (MTF) cut off frequency,Strehl ratio and OQAS values under the contrast of 100％,20％ and 9％ (OV100,OV20,OV9).Results The postoperative BCDVA was not significantly different from preoperative UCDVA in both ICL group and FS-LASIK group (-0.04±t0.10 vs.0.05±0.12;-0.07±0.12 vs.0.00±0.12) (t=3.128,2.358,both at P＞0.05).No statistically significant differnces were found in SE,UCDVA and BCDVA after operation between ICL group and FS-LASIK group (t =1.292,0.900,-0.653,all at P＞0.05).OQAS examination showed that MTF cut off,OSI,Strehl ratio,OV100 were not significantly different after operation between ICL group and FS-LASIK group (t=-2.032,-1.440,-0.224,all at P＞0.05).The postoperative OV20 and OV9 were 0.82±0.14 and 0.80±0.21 in the ICL group,which were significantly higher than those in the FS-LASIK group(0.59±0.15 and 0.47±0.13) (t =4.105,4.702,both at P＜0.05).Conclusions Both ICL implantation and FS-LASIK provide good optical and visual quality for moderate to high myopic eyes,and ICL appears to have a better visual quality in comparison with FS-LASIK under the contrasts of 20％ and 9％.

Early clinical outcomes of small incision lenticule extraction for different refractive myopia and astigmatism / 中华实验眼科杂志

Background Small incision lenticule extraction (SMILE) is increasingly applied in the correction of myopia and astigmatism.However,the early clinical outcomes of SMILE for different refractive myopia and astigmatism is seldom reported.Objective This study was to investigate the safety,efficacy,predictability and early stability after SMILE in low,moderate and high myopia.Methods A series of cases-observational study was carried out.A total of 195 eyes of 108 myopic patients were enrolled in Tianjin Eye Hospital from May to December 2012 under the informed consent.The patients were divided into the low (≤-3.00 D),moderate (＞-3.00 to-6.00 D) and high myopia (＞-6.00 D) groups according to different diopters,with 57 eyes,76 eyes and 62 eyes,respectively.SMILE was performed on all the eyes.The uncorrected visual acuity (UCVA)(LogMAR),best corrected visual acuity (BCVA) (LogMAR),equivalent sphere (SE),intraocular pressure,anterior segment and corneal topography were examined before operation and 1 day,1 week,1 month and 3 months after operation to evaluate the effective index (postoperative UCVA/preoperative BCVA),safety index (postoperative BCVA/preoperative BCVA),predictability and early stability of SMILE.The linear regression analysis was used to analyze the relationships between the attempted refraction and the achieved refraction postoperative 3 months in three groups.Results The percentage of UCVA (LogMAR)＜0.1 was 100％,97.1％ and 92.8％ in the low,moderate and high myopia group,respectively in 3 months after SMILE.The postoperative BCVA of all the operated eyes reached preoperative one.The residual SE was (-0.07±0.16),(-0.05 ±0.20) and (-0.08±0.27)D in the low,moderate and high myopia group,respectively in 3 months after SMILE.The percentage of residual SE±0.5 D was 100％,98.7％ and 93.6％ in the low,moderate and high group,and that of SE±1.0 D was 100％ in all of the groups.The postoperative corrected SE was gradually increased with the raise of predicted SE in the low,moderate and high myopia groups (r=0.942,0.959,0.957,all at P＜0.001).Conclusions SMILE is safe,effective,predictable and stable for the correction of low,moderate and high myopia.The corneal wound healing was slightly slower in the low myopia group than that in the moderate and high group.A slight regression of myopic power appears in high myopia eyes 3 months after SMILE.

Long-time follow-up results of phakic posterior chamber intraocular lens and iris-claw phakic intraocular lens implantation for high myopia / 中华实验眼科杂志

Background With the development of refractive surgery,phakic intraocular lens implantation (PIOL) for high myopia is proving its outstanding merits in short-term treating outcomes.However,its long-term safety and effectiveness were still in more attention.Objective This study was to evaluate and compare the long-term safety,stability and efficacy of Verisyse PIOL implantation with implantable contact lens (ICL) implantation for high myopia.Methods The clinical data of 18 eyes (9 patients) who received Verisyse iris-claw intraocular lens implantation for high myopia and matched 22 eyes (11 patients) who received ICL implantation for high myopia from 2009 to 2011 were retrospectively analyzed.The patients were followed-up for 2 years after surgery.Uncorrected visual acuity (UCVA),best corrected visual acuity (BCVA),spherical equivalence (SE),axial length,corneal endothelial cell density (ECD),contrast sensitivity (CS),wave-front aberrations and postoperative complications were recorded during the following-up.The efficacy index,predictable and safety index were compared between the two groups.Results There was no significant difference in UCVA,BCVA and SE between Verisyse group and ICL group(t =0.92,1.32,4.32;all at P＞0.05).Non-glare CS under the 1.5,3.0,6.0,12.0 and 18.0 c/d spatial frequencies were insignificantly different between the two groups(Z=0.782,0.956,0.495,0.874,0.293;all at P＞0.05),and the similar outcomes were found in glare CS (Z=0.985,1.254,0.896,1.652,0.492;all at P＞0.05) in postoperative 2 years.Root meas square of total high order aberration (RMSh),vertical-trefoil,vertical-coma,horizontal-coma,spherical aberration(SA),were significantly elevated in the Verisyse group compared with the ICL group (Z =4.72,4.24,3.12,3.65,2.16;all at P ＜ 0.05).The mean efficacy index was 108.49 ± 16.62 in the V erisyse group and 106.71±15.88 in the ICL group,showing a significant difference (t =0.54,P＞0.05).The mean safety index was 140.56±33.89 in the Verisyse group and 143.34±34.56 in the ICL group,with a significant difference between them (t=0.29,P＞0.05).The mean predictable index was-0.25(-0.97,4.23)in the Verisyse group and 0.98 (-1.44,1.52) in the ICL group,and the difference was significant (Z =-2.68,P ＜ 0.05).Conclusions Both Verisyse PIOL implantation and ICL implantation for high myopia are safe,predictable and effective.The vusial quality and predictability of ICL implantation are much better than Verisyse PIOL implantation.A long-term effect should be observed for the further evaluation.

Intraocular straylight before and after low myopic photorefractive keratectomy with and without mitomycin C / Dispersão de luz intraocular antes e depois da ceratectomia fotorrefrativa para baixa miopia com e sem mitomicina C

ABSTRACT Purpose: To evaluate ocular straylight before and after photorefractive keratectomy (PRK) for low myopia with and without topical mitomycin (MMC) treatment. Methods: Patients who underwent PRK for low myopia were enrolled into the study. PRK without MMC was performed in 21 eyes (12 patients), whereas PRK with topical 0.02% MMC was performed in 25 eyes (14 patients). Both groups were treated using the NIDEK EC5000 excimer laser. Measurements were performed using the C-Quant straylight meter preoperatively and at two and four months postoperatively. Results: The mean patient age was 30 ± 4 years, and the mean spherical equivalent refractive error was -2.2 ± 0.75 D. The mean preoperative intraocular straylight values were 1.07 ± 0.10 in the PRK without MMC group and 1.07 ± 0.11 log(s) in the PRK with topical MMC group. At two months after surgery, there was a decrease in mean intraocular straylight values in both groups. However, a significant difference was only reached in the PRK with MMC group [0.98 ± 0.09 log(s), p=0.002] compared with preoperative values, which was likely due to a greater scatter of measurements in the PRK without MMC group [1.03 ± 0.13 log(s), p=0.082]. At four months postoperatively, ocular straylight values were not significantly different compared with those at baseline in either the PRK without MMC group [1.02 ± 0.14 log(s), p=0.26] or in the PRK with topical MMC group [1.02 ± 0.11 log(s), p=0.13]. Conclusion: PRK for low myopia decreases ocular straylight, and MMC application further reduces straylight in the early postoperative period. However, ocular straylight values do not significantly differ at four months after surgery compared with those at baseline.

RESUMO Objetivo: Avaliar a dispersão de luz intraocular antes e depois da ceratectomia fotorrefrativa (PRK) para baixa miopia com e sem a aplicação tópica de mitomicina C. Métodos: Pacientes submetidos à PRK para baixa miopia foram selecionados para o estudo. PRK sem MMC foi realizado em 21 olhos (12 pacientes) e PRK com MMC tópica a 0,02% foi realizado em 25 olhos (25 pacientes). Ambos os grupos foram tratados com o excimer laser da Nidek EC5000. Avaliações foram realizadas usando o medidor de dispersão de luz C-Quant no pré-operatório e com 2 e 4 meses de pós-operatório. Resultados: A média de idade dos pacientes foi 30 ± 4 anos e a média do equivalente esférico foi -2,2 ± 0,75 D. As médias da dispersão de luz intraocular no pré-operatório foram 1,07 ± 0,10 no grupo PRK sem MMC e 1,07 ± 0,11 log(s) no grupo PRK com MMC tópica. Após 2 meses da cirurgia houve uma diminuição na média da dispersão de luz intraocular em ambos os grupos. Entretanto uma diferença estatisticamente significante, comparado com os valores pré-operatórios, foi observada apenas no grupo PRK com MMC (0,98 ± 0,09 log(s), p=0,002), provavelmente devido as medidas com maior espalhamento de luz no grupo sem MMC (1,03 ± 0,13 log(s), p=0,082). Após 4 meses de pós-operatório, os valores de dispersão de luz não apresentavam diferença estatisticamente significantes quando comparados com os valores iniciais, tanto no grupo sem MMC (1,02 ± 0,14 log(s), p=0,26) quanto no grupo com MMC tópica (1,02 ± 0,11 log(s), p=0,13). Conclusão: PRK para baixa miopia diminui a dispersão de luz ocular e a aplicação de MMC contribui para uma ainda menor dispersão de luz no período pós-operatório inicial. Entretanto, quatro meses após a cirurgia a dispersão de luz intraocular não é significantemente diferente das medidas pré-operatórias.

The 2-year efficacy study of femtosecond laser corneal small incision lenticule extraction for correction of myopia and myopic astigmatism / 中华实验眼科杂志

Background Researches showed that femtosecond laser corneal small incision lenticule extraction (SMILE) was used in the correction of myopia and myopic astigmatism due to its fast recovery,good shortterm efficacy and few complications.However,few research focused on its long-term efficacy.Objective Thisstudy was to evaluate the effectiveness,safety,predictability,stability and complications of SMILE.Methods A serial cases-observational study was carried out under the approval of Ethic Committee of Henan Eye Institute and informed consent of patients.Sixty-seven eyes of 34 patients with myopia and myopic astigmatism were included in Henan Eye Institute from January to June 2013.All the patients received SMILE and followed-up for 2-year duration.The uncorrected visual acuity (UCVA),best corrected visual acuity (BCVA),automatic optometry,intraocular pressure and corneal topography were examined before surgery and 1 day,1 week,1 month,3 months,1 year and 2 years after surgery and calculated the spherical equivalent (SE).The long-term efficacy of SMILE included effective index (preoperative BCVA/postoperative UCVA),safety index (postoperative BCVA/ preoperative BCVA),predictability (linear regression analysis between actual SE and attempted SE) and refractive stability (SE changes at postoperative time points).Results The preoperative BCVA was ≥ 20/20 in 60 eyes with the percentage of 89.55％.UCVA≥ 20/20 were found in 61 eyes and 60 eyes in postoperative 3 months and 2 years respectively (91.04％ and 89.55％).The effective index was 1.038±0.182 and 1.029±0.231 in postoperative 3 months and 2 years respectively,showing an insignificant difference between them (t =0.400,P ＞ 0.05).Compared with the preoperative BCVA,8.96％ (6/67) and 10.45％ (7/67) eyes lost 1 line at 3 months and 2 years after surgery,respectively.The safety indexes were 1.141±0.193 and 1.312±0.242 at 3 months and 2 years after surgery,with no significant difference between them (t =0.414,P＞0.05).A linear correlation was found between actual SE and attempted SE both at postoperative 3 months and 2 years,with the linear regression equations of Y=0.897 1X-0.440 8 (R2 =0.914 2,P＜0.05) and Y =0.893 7X-0.382 3 (R2 =0.915 7,P＜0.05),respectively.The SE was (0.013±0.578),(-0.033±0.489),(-0.106±0.508),(-0.103±0.375),(-0.154±0.518) and (-0.147±0.366)D 1 day,1 week,1 month,3 months,1 year and 2 years after surgery,respectively,and there were no significant difference among different time points (F =0.185,P =0.176).Eighteen in the 67 eyes occurred opaque bubble layer after surgery.Diffuse lamellar keratitis appeared in 6 eyes and punctate keratitis was in 2 eyes.These complications were cured 1 month after administration of drugs.Conclusions SMILE is good in effectiveness,safety,predictability and refreactive stability and has fewer complications during 2-year following-up.

Corneal aberrations and visual performance after flap creation of LASIK with a femtosecond laser and a mechanical microkeratome / 中华实验眼科杂志

Background Laser in situ keratomileusis (LASIK) for myopia and/or myopic astigmatism still is one of primary surgeries.Femtosecond laser (FS)-LASIK offers several advantages over microkeratomes for flap creation including better safety,reproducibility,and predictability.However,the visual performance after FS-LASIK is of high clinical concern.Objective This study was to compare the visual performance between Intralase FS60 femtosecond laser flap and mechanical microkeratome Moria M2 flap in LASIK.Methods A prospective nonrandomized controlled study was performed.Two hundred and four myopic eyes of 102 patients were enrolled in this study and divided into two groups according to patients’ opinion,with matched demography between the two groups.LASIK with FS60 femtosecond laser flap was performed on 100 eyes of 50 myopia and/or myopic astigmatism in the FS group,and Moria M2 flap LASIK was performed on 104 eyes of 52 patients in the microkeratomes group.Zernike coefficients and the root-mean-square (RMS) of higher order aberrations were measured by Wavescan wavefront aberrometer before and 3,6 and 12 months after surgery,and the contrast sensitivity (CS) in different spatial frequencies under the scotopia and scotopia + glare background was detected using Optec 6500 visual function instrument before and 3,6,12 months after surgery.This study protocol was approved by Ethic Committec of Beijing Tongren Hospital,and written informed consent was obtained from each patient prior to surgery.Results The uncorrected visual acuity (UCVA) levels after surgery reached or was superior to the preoperative best corrected visual acuity (BCVA) in 95.1％,94.2％ and 93.9％ patients in the FS group and in 94.2％,93.8％ and 93.2％ patients in the microkeratomes group 3,6,12 months after surgery,respectively.The mean spherical equivalent (SE) was (-6.37 ±2.06)D,(-0.26±0.45)D and (-0.45± 0.51)) in the FS group,(-6.25± 2.43) D,(-0.44± 0.64) D and (-0.35±0.59)D in the microkeratomes group before surgery and 3,12 months after surgery,respectively.There were no significant differences in the SE in various time points between the two groups (u =1.194,1.429;both at P＞ 0.05).The root means square high order (RMSh) and RMS3-6 in the FS group were significantly lower than those in the microkeratomes group 3,6 and 12 months after surgery (all at P＜0.05).Under the background of scotopia or scotopia+glare,the LogCS values under different spatial frequencies were significantly higher in the FS group than those in the microkeratomes group 3 and 6 months after surgery (all at P＜0.05).In 12 months after surgery,no significant difference was found in the LogCS under the 1.5 c/d in the background of scotopia between FS group and microkeratomes group (P＞0.05),and the LogCS values under the 12.0 c/d and 18.0 c/d in the background of scotopia or scotopia+glare in the FS group were better than those in the microkeratomes group (all at P＜0.05).Conclusions Femtosecond laser assistant LASIK has better visual performance and lower higher-order aberrations than microkeratomes assistant LASIK.

Change of higher order aberration after 2 mm micro-incision SMILE in myopia / 中华实验眼科杂志

Background Small incision lenticule extraction (SMILE) is increasingly used for myopia.However,the size of the incision varied in different operators.The influence of 2 mm micro-incision SMILE on postoperative diopter and aberrations is not clear yet.Objective The aim of the current study was to perform a clinical analysis of the efficacy,safety,stability and predictability of 2 mm micro-incision SMILE and investigate the influence of preoperative sphere and cylinder power on postoperative aberrations.Methods A serial cases observational study was carried out under the approval of Ethic Committee of Tianjin Eye Hospital and informed consent of each patient.Fifty-five eyes of 31 subjects with myopia and myopic astigmatism were enrolled in this study in Tianjin Eye Hospital from January to April 2013 and a 2 mm micro-incision SMILE was performed on the eyes.Follow-up visits were performed at 1 week,1 month and 6 months after operation.Uncorrected visual acuity (UCVA),best corrected visual acuity (BCVA),manifest and cycloplegic refraction were examined at each postoperative time points to evaluate the efficacy,safety,stability and predictability of 2 mm micro-incision SMILE.Wave-front aberrations were measured by WaveScan aberrometer.Repeated measurement analysis of variance was used for the comparison of the differences of aberrations before and after the surgery.And the differences between various follow-up visits were compared with LSD-t test.The relationship between preoperative sphere or cylinder power and aberrations postoperatively were analyzed by Spearman rank correlation.Results At 1 week,1 month and 6 months postoperatively,the effective index was 1.2,and the safety indexes were 1.2,1.2 and 1.5 respectively.The spherical equivalent remained 0.00 D at each postoperative time point.And 96.4％ and 97.8％ of eyes were within ±0.5 D of intend correction and 100％ were within ± 1.0 D of the intend correction at 1 month and 6 months postoperatively.Vertical coma (Z7) and spherical aberration (Z12) were significantly raised at 1 week,1 month and 6 months after surgery compared with the values preoperatively (Z7:t =9.668,10.607,9.772,all at P ＜ 0.001 ;Z 12:t =-6.227,-6.923,-7.441,all at P＜0.001).The Zernike coefficients were relatively symmetrical between various time points postoperatively (all at P＞0.05).Third-order to sixth-order aberrations and higher order abberration (HOA) showed significant increase at various time points after the surgery compared with the values before surgery (all at P＜0.05),and no significant differences were seen between various follow-up visits (all at P＞0.05).Positive correlations were found between preoperative sphere and S3,S4 and HOA at 1 week,1 month and 6 months postoperatively (P＜0.05).Negative correlations were found between preoperative cylinder and S3,S4 and HOA at postoperatively various time points (all at P＜0.05).In addition,significant positive correlations were seen between Z7 and preoperative cylinder as well as between Z12 and sphere preoperatively,and negative correlations also were observed between Z7 and preoperative sphere as well as between Z12 and cylinder preoperatively at each follow-up visits(all at P＜0.05).Conclusions SMILE with 2 mm micro-incision is a safe,effective,stable and predictable procedure for myopic and myopic astigmatism eyes.The aberrations and Zernike terms remain stable after surgery until 6 months although these parameters present elevation to a certain extent.Preoperative SE and astigmatism power affect postoperative aberrations.

Clinical comparison between brachytherapy of 0.5 ％ loteprednol etabonate eye drops and long-term therapy of 0.1％ fluorometholone eye drops after LASEK / 中华实验眼科杂志

Background Conventional corticosteroid therapy after laser epithelial keratomileusis (LASEK) is topical application of 0.1％ fluorometholone eye drops for 4 months,but this therapy increases the ocular hypertension risk and leads to poor compliance in patients.It is necessary to explore a safe and effective brachytherapeutic drug.Objective This study was to compare the clinical outcomes between the brachytherapy of 0.5％ loteprednol etabonate eye drops and the long-term therapy of 0.1％ fluorometholone eye drops after LASEK.Methods Clinical data were retrospectively analyzed from 208 right eyes in 208 mild and moderate myopia patients who received LASEK at Peking University Third Hospital from 2009 to 2013.The eye drops of 0.5％ loteprednol etabonate was used 6 times daily since operation day until postoperative day 5,and 4 times daily for a week,and then tapered for three consecutive weeks in 104 eyes of the loteprednol group after LASEK,and 0.1％ fluorometholone eye drops was applied topically 4 times daily for initial one month and then tapered for three consecutive months in another 104 eyes in the fluorometholone group after LASEK.Corneal epithelial healing time was compared between the two groups by recording the wearing duration of corneal contact lens.Noncontact intraocular pressure (lOP) was detected and corrected 5 days,2 weeks,1 month and 3,6 months after LASEK.Haze was scored based on the criteria of Cheng under the slit lamp microscope and apparently optometry was performed 1 month and 3,6 months after LASEK.Results The number of eyes removed corneal contact lens in 5,6 and 7 days after LASEK was not significantly different between the loteprednol group and the fluorometholone group (x2 =1.180,P =0.554).No considerable differences were seen in the eye numbers with the equivalent spherical lens (absolute value) ≤0.5 D in 1 month,3months and 6 months after LASEK (Z=-1.028,P=0.304;Z=-0.398,P=0.691;Z=-0.445,P=0.656).In the fifth days after surgery,the median corrected IOP was 13.52 mmHg and 13.12 mmHg in the loteprednol group and the fluorometholone group,respectively,showing a significant difference between them (Z =-1.985,P =0.047),but no significant differences were found in IOP in 2 weeks,1 month and 3 months,6 months after surgery between the two groups (all at P＞0.05).IOP elevated (postoperative IOP-preoperative IOP ≥ 5 mmHg) after LASEK in 5 eyes in the loteprednol group and 4 eyes in the fluorometholone group (x2 =0.116,P =0.733).In 1 month after surgery,the number of eyes in different grades of haze was significantly decreased in the loteprednol group compared with the fluorometholone group (x2=13.506,P=0.009),however,there was no significant differences in haze grading in postoperative 3 months and 6 months between the two groups (x2 =2.199,P =0.699;x2 =1.154,P =0.562).Conclusions Brachytherapy of 0.5％ loteprednol etabonate eye drops appears to have a similar effect in antiinflammation and inhibition of haze to the long-term therapy of 0.1％ fluorometholone eye drops after LASEK.Furthermore,topical application of 0.5％ loteprednol etabonate eye drops dose not increase the risk of ocular hypertension.

Influence of different types of corneal laser refractive surgeries on corneal hysteresis and corneal resistance factor in myopic eyes / 中华实验眼科杂志

Background Refractive surgery has propelled itself forward to become widely performed surgical procedure nowadays.After the surgery,corneal biomechanics decreases lead to keratoconus and corneal ectasia.Doctors pay more attention to biomechanics changes after refractive surgeries.Objective This clinical study was to investigate the influence of different laser refractive surgeries on corneal biomechanics.Methods A prospective nonrandomized and controlled clinical study was designed.One hundred and sixty-four eyes of 82 patients with moderate myopia were enrolled.The patients were divided into sub-Bowman keratomileusis (SBK) group (60 eyes of 30 patients),laser in situ keratomileusis (LASIK) group (54 eyes of 27 patients) and laser subepithelial keratomileusis (LASEK) group (50 eyes of 25 patients),with the matched demography among the three groups.Corneal hysteresis (CH) and corneal resistance factor (CRF) were detected by ocular response analyzer (ORA) before and 1 week,5 months after refractive surgery.The correlations between stromal ablation depth and postoperative changing values of CH or CRF were analyzed.Results Significant differences were found in CH and CRF at different time points in the three groups (Ftime =41.90,P =0.00;Ftime =49.65,P =0.00),and the CH and CRF values were significantly lower 1 week and 5 months after surgery than those before surgery (all at P =0.00).However,no significant difference of CH or CRF was seen at all time points among the three groups (Fgroup =2.17,P =0.08;Fsroup =2.67,P =0.07).No correlation was found between corneal ablation depth and CH in 1 week and 5 months after surgery (both at R2 =0.000),however,weaker correlations were seen between corneal ablation depth and CRF 1 week and5 months after surgery (Y=3.253+ 0.010X,R2=0.007;Y=1.073+0.021 X,R2=0.004).Conclusions SBK,LASIK and LASEK lead to the change of corneal biomechanics by altering CH and CRF,they play the same influence on cornea.CRF appears to be an useful indicator in evaluating corneal biomechanical changes after laser refractive surgery.

Comparison of clinical effectiveness between transepithelial PRK and Epi-LASIK for myopia with thin cornea / 中华实验眼科杂志

Background Integrated transepithelial photorefractive keratectomy (TransPRK) is a new kind of surface ablation and has a fast reepithelialization and uncorrective visual acuity (UCVA) recovery as well as slighter postoperative pain,and epipolis laser in situ keratomileusis (Epi-LASIK) has been recognized to be an effective method for myopia.But there have been few studies to evaluate the dynamic change of the corneal biomechanical properties and posterior corneal elevation after TransPRK.Objective This study was to assess and compare the effectiveness and safety between TransPRK and Epi-LASIK for myopia with thin cornea.MethodsThis study was approved by Ethic Committee of Jinan Mingshui Eye Hospital,and written informed consent was obtained from each patient.In this prospective non-randomized controlled study,93 right eyes of 93 myopic patients with the central corneal thickness 460 to 500 μm were included in Jinan Mingshui Eye Hospital from June to December 2013 under the informed consent.The eyes were divided into TransPRK group for 46 eyes and Epi-LASIK group for 47 eyes.UCVA,manifest refraction,haze,corneal biomechanical properties,posterior corneal elevation,Qvalue and corneal high order wavefront aberration were analyzed before and 1 week,1 month,3 months and 6 months after operation,respectively,and the examination results were compared between the two groups.Results There was no statistically significant difference in the eyes of postoperative UCVA and manifest refraction between the TransPRK group and the Epi-LASIK group at various time points (all at P＞0.05).Six months after surgery,the percentage of eyes with UCVA of 1.0 or better was 93.9％,and 90.9％ eyes exhibited the targeted refraction in ± 1.00 D in the TransPRK group.Corneal haze was most obvious 1 month after surgery in both groups,with the incidence of 32.6％ (15/46) in the TransPRK group and 17.4％ (8/47) in the Epi-LASIK group,but no significant difference was found in the eye numbers with haze between the two groups (x2 =2.841,P =0.092).No significant differences were seen in the corneal hysteresis(CH) values and corneal resistance factor(CRF) values between the two groups (CH:Fgroup =0.000,P =0.999;CRF:Fgroup =0.110,P =0.741),however,the postoperative CH values and CRF values were significantly declined in comparison with preoperative ones,with significant differences among various time points (CH:Ftime =103.658,P =0.000;CRF:Ftime =132.008,P =0.000),while there were no remarkable differences between any two time points in postoperation (all at P＞0.05).Posterior corneal surface height shifted rearward 1 week,1 month,3 months and 6 months after surgery,showing remarkable differences in comparison with before surgery in both groups (Ftime =12.868,P =0.001),but no significant differences between the two groups (Fgroup =1.923,P=0.169).No significant differences were found in Q-value between the two groups (Fgroup =0.191,P=0.663).Root mean square (RMS) and spherical aberration values elevated in postoperation compared with preoperation,with significant differences between them(all at P＜0.01),but the comparison between intergroup was insignificant (RMS:Fgroup =0.299,P =0.586;Spherical aberration:Fgroup =1.290,P =0.259).Conclusions TransPRK for myopia with thin cornea is safe and stably effective like Epi-LASIK.TransPRK affects corneal biomecbanical properties early after surgery but the effect gradually lessens over time.The posterior corneal elevation shows a tiny backward displacement,while posterior corneal asphericity has no change.

Implantable collamer lens and femtosecond laser for myopia: comparison using an adaptive optics visual simulator / Lente implantável de collamer e laser de femtosegundo para miopia: comparação usando um simulador visual de óptica adaptativa

Purpose: To compare optical and visual quality of implantable collamer lens (ICL) implantation and femtosecond laser in situ keratomileusis (F-LASIK) for myopia. Methods: The CRX1 adaptive optics visual simulator (Imagine Eyes, Orsay, France) was used to simulate the wavefront aberration pattern after the two surgical procedures for -3-diopter (D) and -6-D myopia. Visual acuity at different contrasts and contrast sensitivities at 10, 20, and 25 cycles/degree (cpd) were measured for 3-mm and 5-mm pupils. The modulation transfer function (MTF) and point spread function (PSF) were calculated for 5-mm pupils. Results: F-LASIK MTF was worse than ICL MTF, which was close to diffraction-limited MTF. ICL cases showed less spread out of PSF than F-LASIK cases. ICL cases showed better visual acuity values than F-LASIK cases for all pupils, contrasts, and myopic treatments (p<0.05). No statistically significant differences were found in contrast sensitivities between ICL and F-LASIK cases with -3-D myopia for both pupils for all evaluated spatial frequencies (p>0.05). For -6-D myopia, however, statistically significant differences in contrast sensitivities were found for both pupils for all evaluated spatial frequencies (p<0.05). Contrast sensitivities were better after ICL implantation than after F-LASIK. Conclusions: ICL implantation and F-LASIK provide good optical and visual quality, although the former provides better outcomes of MTF, PSF, visual acuity, and contrast sensitivity, especially for cases with large refractive errors and pupil sizes. These outcomes are related to the F-LASIK producing larger high-order aberrations. .

Objetivo: Comparar a qualidade óptica e visual da lente implantável de collamer (ICL) e da ceratomileuse in situ com laser de femtosegundo (F-LASIK) na correção de miopia. Métodos: O simulador visual de óptica adaptativa CRX1 (Imagine Eyes, Orsay, França) foi usado para simular o padrão de aberração de frentes de onda, depois de dois procedimentos cirúrgicos: implante de ICL e tratamento F-LASIK para -3 e -6 D. A acuidade visual em diferentes contrastes e sensibilidade ao contraste em 10, 20 e 25 ciclos/grau (cpd) foram medidos para pupilas de 3 e 5 mm. A função de transferência de modulação (MTF) e a função de espalhamento de ponto (PSF) foram calculados para a pupila de 5 mm. Resultados: A MTF do F-LASIK foi pior do que a do ICL, que estava perto da MTF do limite de difração. A ICL apresentou menor espalhamento do PSF do que o F-LASIK. ICL apresentou melhores valores da acuidade visual do que F-LASIK para todas as pupilas, contrastes e tratamentos miópicos (p<0,05). Não foram encontradas diferenças estatisticamente significantes na sensibilidade ao contraste entre ICL e F-LASIK de -3 D, para ambas as pupilas e quaisquer frequências espaciais avaliadas (p>0,05). Por outro lado, para -6 D, diferenças estatisticamente significativas na sensibilidade ao contraste foram encontrados para ambas as pupilas e todas as frequências espaciais avaliadas (p<0,05). Sensibilidade ao contraste foi melhor após o implante da ICL que após o F-LASIK. Conclusões: ICL e F-LASIK proporcionam uma boa qualidade óptica e visual, embora a ICL oferece melhores resultados de MTF, PSF, acuidade visual e sensibilidade ao contraste, especialmente para grandes erros de refração e tamanhos de pupila. Estes resultados estão relacionados ao procedimento F-LASIK que induz maiores aberrações ...

Causes of increased corneal aspherical index following LASIK for myopia / 中华实验眼科杂志

Background Laser assisted in situ keratomileusis (LASIK) for myopia will change corneal asphericity and further affect the quality of vision.However,how operating parameters such as ablation depth and optic zone diameter affect corneal asphericity is still rarely reported.Objective Aim of this study was to investigate the influence of corneal ablation depth and optic zone diameter on corneal asphericity after LASIK for myopia.Methods This prospective study comprised 175 eyes of 89 patients with the spherical equivalent of (-5.93± 1.98)D and the best corrected visual acuity (BCVA) ≥ 1.0.The flap creation with the femtosecond laser combine iris recognize guided LASIK was performed on the patients who were available for the evaluation at postoperative 6 months.Corneal aspherical index (Q value) at the central corneal 6.0 mm were measured with Orbscan IIz-corneal topography before and 6 months after operation.Corneal ablation depth and optic zone diameter were recorded in operation.The changes of visual acuity and spherical equivalent before and after surgery were compared by self-control method,and the correlations between corneal ablation depth or optic zone diameter with alteration of Q value (AQ) after LASIK were assessed using multiple regression analysis.Results The mean spherical power,cylinder diopter and spherical equivalent were (-5.57 ± 1.89) D,(-0.71 ±0.55) D and (-5.93 ± 1.98) D before surgery,and those after surgery were (-0.25 ±0.30),(-0.14±0.22)D and (-0.32±0.37)D,showing significant differences between before and 6 months after LASIK (t=-32.39,-23.91,-35.18,all at P＜0.01).The Q values at the central corneal 6.0 mm were -0.13 ± 0.09 (-0.47-0.08) in preoperation and 1.09 ± 0.54 (0.22-2.51) in postoperation,with a significant increase in postoperation (t=29.37,P＜0.01).Corneal ablation depth was (95±28) μm and optic zone diameter was (6.32±0.26)mm.Ablation depth appeared to be positive correlation with AQ (β =0.803),and optic zone diameter showed a negative correlation with AQ (β =-0.149),with a multiple regression formula AQ =1.517+0.015×ablation depth-0.3 ×optic zone diameter.Conclusions LASIK for myopia increase corneal Q value.The increase of corneal ablation depth and decrease of optic zone diameter contribute to enlargement of corneal Q value.

The randomized controlled study on timolol preventing refractive regression after LASIK in high myopic eyes / 中华实验眼科杂志

Background Refractive regression is a common complication of high myopia after laser in situ keratomileusis (LASIK),and it affects the stability of surgery.Objective This study was to observe the preventive effect of timolol on refractive regression in high myopia after LASIK.Methods A perspective randomized controlled trial was performed under the approval of Affiliated Hospital of Zunyi Medical College and the informed consent of the patients.Sixty eyes of 60 patients with high myopia (-7.16±0.95) D for LASIK were randomized into experimental group and control group.Regular eye drops were topically administered in the patients after LASIK in both groups,and timolol 0.5 ％ was added topically from 1 day after LASIK.The uncorrected visual acuity (UCVA),best corrected visual acuity (BCVA),spherical equivalent (SE),corneal anterior surface curvature,intraocular pressure (IOP),central corneal thickness (CCT) were measured before LASIK,1 week,1 month,3 months and 6 months after LASIK,respectively.Residual stromal bed thickness was calculated before LASIK.The differences of above-mentioned indexes were analyzed and compared between the two groups and among the various time points using repetitive measurements analysis of variance,independent simple t test and Bonferroni test.Results No significant differences were found in the demography between the experimental group and the control group,including age,UCVA,BCVA,SE,IOP,corneal anterior surface curvature,CCT and residual stromal bed thickness (all at P＞0.05).UCVA was significantly different between the two groups among various time points (Fgroup =3.91,P＜0.05 ; Ftime =3.80,P＜0.05),and the UCVA was significantly higher in the experimental group than the control group 6 months after LASIK (t=2.97,P＜0.05),and UCVA was gradually increased as the lapse of postoperative time with the significant difference between 7 days and 6 months after LASIK in the experimental group (P＜0.05).No significant difference was seen in the BCVA between the two groups at various postoperative time points (Fgroup =2.44,P＞0.05;Ftime =2.31,P＞0.05).SE refraction in both groups were significantly reduced from 7 days through 6 months after LASIK,showing significant difference between the groups at various time points after LASIK(Fgroup =11.52,P＜0.05;Ftime =22.06,P＜0.05).The SE refraction was higher in the experimental group than that in the control group 6 months after LASIK (t =2.47,P＜0.05).Corrected IOP in the experimental group was lower than that of the control group at 7 days,1 month and 3 months after LASIK,respectively (Fgroup =14.83,P＜0.05).The change of CCT was not statistically different between the control group and the experimental group (Fgroup =0.04,P＞0.05).The anterior corneal surface curvature was steady in the experimental group during the following-up duration after LASIK,while the control group was growing gradually (Ftime =18.73,P＜0.05).Conclusions The study data show that topical administration of 0.5％ timolol early in high myopia following LASIK is effective for the reduction of the refractive regression.It is suggested that 0.5％ timolol can prevent cornea ectasia by lowering IOP.Reduction of the IOP may contribute to improving the regression after keratorefractive surgery in high myopic eyes.

Five years evaluation of laser in situ keratomileusis for myopia / 眼科

Objective To evaluate five years results of laser in situ keratomileusis(LASIK)for correction of myopia.Design Ret- rospective case series.Participant 64 patients(126 eyes)with myopia received operation of LASIK.Method 126 myopic eyes were treated with LASIK.Based on the preoperative spherical equivalent refraction(SER),the patients were divided into Group A,B and C(-3.00D～6.00D,-6.25D～-10.00D and -10.38D～-19.88D).Before and after operation,the visual acuity,refraction,anterior seg- ment,funduscopy,intraocular pressures of patients were measured,and the patients were followed-up five years.Main Outcome Measure Visual acuity,intraocular pressure,refraction and complication.Result At five years,in Group A,B,C,uncorrected visual acuity was≥1.0 in 87.2%,69.1%,31.3% patients,and 100%,98.2%,75% had vision of≥0.5.After five years of operation,the re- fraction was -0.70D?0.52D,-1.06?0.13D,-2.46?2.14D in three groups respectively,there was no significant difference between Group A and B(P=0.23);But there was significant statistical difference between Gruop A and C(P=0.008),Group B and C(P=0.021)respec- tively.At the fifth-year,68.3%,45.0% and 23.5% of refraction in Group A,B,C were within?1.00D.Intraocular pressure at the fifth year was 11.91?2.35mmHg,11.31?2.20 mmHg and 9.24?2.20 mmHg respectively.In Gruop B and C,one patient complained glare re- spectively.In Gruop B,one patient's intraecular pressure was elevated after using glueocorticoid.In Group C,one eye was complicated with rbegmatogenous retinal detachment at the second year after LASIK.Conclusion In the follow-up of five years,LASIK is effective and safe.The results in middle and high myopia are better than that in extreme high myopia.(Ophthalmol CHN,2006,15:312-314)

Bhanges of corneal refractive power aftert he implantation of intrastromal corneal ring / 中华实验眼科杂志

ObjectiveTo evaluate the safety and efficacy of the refractive effect produced by the implantation of intrastromal corneal ring （ICR）．MethodsEach of the 60 eyes （30 rabbits） received an ICR．The thickness of the ICRs varied from 0.19mm to 0.41mm．Each eye underwent a preoperative and postoperative examinations at the lst，3rd，7th and 14th day；the lst，3rd and 6th month．Slit-lamp biomicroscopy and an ORBSCANTM slit scan corneal tomography／pachymetry system were performed at predetermined intervals throughout the follow-up periods．ResultsThe decrease of corneal curvature was observed after ICR implantation in all of the eyes．There was a direct relationship between the ICR thickness and the degree of corneal flattening achieved．The equation is：D＝1.4353－32.87×thickness．The postoperative refractive effect was stable．Wound healing was uncomplicated and central cornea remained transparent．ConclusionThe ICR implantation is safe and effective and the refractive effect is predictive and stable．

Histopathological findings in human epikeratophakia lenticules / 眼科

Six human epikeratophakia lenticules were remo- ved 1 to 23 months after refractive keratoplasty for aphakia(2)and myopia(3).The myopic group in- cluded one epi-lens treated with ArF-excimer laser for hyperopia.Causes of removal were epithelial de- fect(4),edema of host cornea(1)and overcorre- ction(1),The epi-lens stroma showed a central regular fibrillar structure with a low keratocyte den- sity.Electronmicroscopy revealed preserved cytoplas- mic organelles and nuclear appearance.Lymphocytes and other mono-nuclear cells were absent,Bowan's membrane was normal in all cases.Breaks were not seen while a slight wavy appearance and occasionally focal bends occurred.The epithelium was somewhat irregular and changing in thickness.In the peripher- al wound region stromal and epithelial irregularities were evident.