Comparison of central corneal thickness treated with small incision lenticule extraction, femtosecond laser-assisted in situ keratomileusis, or laser-assisted subepithelial keratomileusis for myopia.

To compare the central corneal thickness (CCT) treated with small incision lenticule extraction (SMILE), femtosecond laser-assisted in situ keratomileusis (FS-LASIK), or laser-assisted subepithelial keratomileusis (LASEK) for myopia correction. This was a retrospective case series study. Patients who had completed 1-year follow-up after receiving SMILE, FS-LASIK, or LASEK at our hospital from January 2019 to July 2021 were included. Pentacam pachymetry was performed to measure the CCT. The predicted CCT reduction was obtained through laser platform. The measured CCT reduction was defined as the difference between the preoperative and postoperative CCT using Pentacam pachymetry. There were 100 eyes treated by SMILE, 100 eyes by FS-LASIK, and 100 eyes by LASEK. There was a significant difference in predicted CCT reduction among the three surgeries (P < 0.001), but no significant difference in measured CCT reduction postoperatively (PGroup = 0.373). At 1 year postoperatively, the CCT reduction was overestimated by 17.85 ± 5.36 µm in the SMILE group, underestimated by 4.31 ± 7.08 µm in the FS-LASIK group, and underestimated by 7.60 ± 8.28 µm in the LASEK group (PGroup < 0.001, PTime < 0.001). In the FS-LASIK group, the difference between predicted and measured CCT reduction was not related to the predicted CCT reduction (P = 0.095). The laser platform may overestimate the CCT reduction for SMILE and underestimate it for FS-LASIK and LASEK. FS-LASIK has a much higher level of accuracy in CCT reduction, which is not influenced by refractive correction.

Long-term visual quality after small incision lenticule extraction (SMILE) and laser assisted subepithelial keratomileusis (LASEK) for low myopia.

BACKGROUND: Few studies have reported the visual outcomes of small-incision lenticule extraction (SMILE) and laser-assisted subepithelial keratomileusis (LASEK) for myopia correction. This study aims to compare the visual quality and corneal wavefront aberrations after SMILE and LASEK for low-myopia correction. METHODS: In this prospective study, we included 29 eyes of 29 patients who received SMILE and 23 eyes of 23 patients who received LASEK between June 2018 and January 2019. The following measurements were assessed: uncorrected (UDVA) and corrected (CDVA) distance visual acuity, manifest refraction, corneal wavefront aberrations, and subjective visual quality. All patients were followed up for two years. RESULTS: All procedures were uneventful. An efficacy index of 1.19 ± 0.17 was established in the SMILE group and 1.23 ± 0.20 in the LASEK group. No eyes lost more than two lines of CDVA. We found that 93% (27/29) of the treated eyes in the SMILE group and 91% (21/23) in the LASEK group had spherical equivalent (SE) within ± 0.25D. The increases in the total corneal spherical aberration and the corneal front spherical aberration were lower in the SMILE group than in the LASEK group (P < 0.01). In contrast, the increases in the total corneal vertical coma and the corneal front vertical coma in the SMILE group were greater than those in the LASEK group (P < 0.01). CONCLUSION: Both SMILE and LASEK have good safety, stability, and patient-reported satisfaction for low myopia. SMILE induced less corneal spherical aberration but greater vertical coma than LASEK.

Postoperative corneal biomechanics and influencing factors during femtosecond-assisted laser in situ keratomileusis (FS-LASIK) and laser-assisted subepithelial keratomileusis (LASEK) for high myopia.

The purpose of this study is to compare the postoperative corneal biomechanics and assess the influence factors after femtosecond-assisted laser in situ keratomileusis (FS-LASIK) and laser-assisted subepithelial keratomileusis (LASEK) for high myopia. In this retrospective study, patients who completed 1-year follow-up were included. The corneal biomechanical parameters, including deformation amplitude ratio 2.0 mm (DA ratio 2.0 mm), integrated inverse radius (IntInv Rad), stiffness parameter at first applanation (SP-A1), and Ambrosio relational thickness through the horizontal meridian (ARTh), were measured with Corvis STII. We also investigated the relationship between these biomechanics and preoperative or intraoperative variables. Thirty eyes had FS-LASIK and 30 eyes had LASEK. The changes in DA ratio 2.0 mm, IntInv Rad, and SP-A1 after surgery were significantly smaller in the LASEK group than in the FS-LASIK group, while the change in the ARTh was not significantly different between groups. No significant differences were detected in the mean values of postoperative DA ratio 2.0 mm, IntInv Rad, and SP-A1 between LASEK and FS-LASIK, while significant difference was detected in the mean value of postoperative ARTh. There was a significant correlation between the resident stromal bed thickness and the postoperative DA ratio 2.0 mm, IntInv Rad, or SP-A1. The postoperative ARTh has shown significant correlation with postoperative central corneal thickness and the amount of myopic correction. The effect of LASEK on corneal biomechanics was smaller than FS-LASIK when the same central corneal thickness was consumed. LASEK may be performed with a lower risk of postoperative corneal ectasia than FS-LASIK.

Long-Term Visual and Refractive Stability and Ocular Biometric Changes after Laser-Assisted Subepithelial Keratomileusis for Correction of Myopia: An 8-Year Follow-Up.

PURPOSE: To assess the long-term visual and refractive stability and ocular biometric changes in low to moderate myopic subjects treated by laser-assisted subepithelial keratomileusis (LASEK). METHODS: It is a prospective, interventional study. Included were 70 eyes of 35 patients who underwent LASEK for correction of ≤6 diopters (D) myopia. The uncorrected and corrected distance visual acuity (UDVA and CDVA), manifest refractions, and ocular biometric indices (by Lenstar-LS900, Haag-Streit AG, Koeniz, Switzerland) including keratometry, anterior chamber depth (ACD), aqueous depth (AD), axial length (AL), central corneal thickness (CCT), and lens thickness (LT) were assessed preoperatively and after 6 months and 8 years. RESULTS: Mean preoperative spherical equivalent was -3.99 (standard deviation [SD] =1.38) D which improved to 0.02 (SD = 0.27, P < 0.001) D and -0.10 (SD = 0.31, P < 0.001) D at 6 months and 8 years, respectively. The preoperative AL was not different from postoperative measures at 6 months (P = 0.15) and 8 years (P = 0.47). The ACD and AD decreased during 8 years, while LT increased (all P ≤ 0.001). The changes of LT inversely correlated with changes of ACD (rs = -0.67, P = 0.001 at 6 months and rs = -0.87, P < 0.001 at 8 years) and AD (rs = -0.76, P < 0.001 at 6 months and rs = -0.86, P < 0.001 at 8 years). The CCT and keratometry values reduced at 6 months postoperatively (all P < 0.001) and then did not change up to 8 years (0.21 ≤ P ≤ 0.87). CONCLUSIONS: The post-LASEK myopic regression is 0.1 D over 8 years. Ocular biometric values like keratometry, CCT, ACD, AD, and LT have been changed for a long period after LASEK in low to moderate myopia except AL.

Comparison of the Levels of Transforming Growth Factor-ß1 in Tear Fluid in Patients with High Myopia after Transepithelial Photorefractive Keratectomy and Laser Subepithelial Keratomileusis (LASEK).

We compared the level of transforming growth factor-ß1 (TGF-ß1) in the tear fluid of 20 patients with high myopia who underwent transepithelial photorefractive keratectomy (T-PRK) in one eye and laser subepithelial keratomileusis (LASEK) in the contralateral eye. Tear fluid samples were collected with scaled microcapillary tubes before (day 0) and on days 1, 3, and 5 after surgery. The release of TGF-ß1 was determined by multiplying the concentration of TGF-ß1 by capillary tear fluid flow. Corneal haze was also evaluated in 1, 3, and 6 months after surgeries. The median TGF-ß1 release after T-PRK and LASEK differed significantly on days 1 and 3 (p<0.005) and on day 5 (p<0.05). The mean corneal haze score after T-PRK and LASEK also significantly differed in 1 month (p<0.005), but no significant differences in this parameter were revealed at later terms. Thus, the level of TGF-ß1 in the tear fluid after T-PRK was lower than after LASEK, which can be the cause of less pronounced corneal haze in 1 month after surgery.

Comparison of Higher-Order Aberrations after LASEK between Two Different Laser Platforms for Low-to-Moderate Myopia.

PURPOSE: To compare the differences in higher-order aberrations (HOAs) after laser subepithelial keratomileusis (LASEK) between two different laser platforms. METHODS: One hundred and seven eyes of 107 patients were included in this study. Fifty-six eyes underwent LASEK with the Triple-A profile (an ablation profile of the MEL 90 excimer laser) and 51 eyes underwent LASEK with the aspheric (Aberration Smart Ablation [ASA]) profile. Uncorrected distance visual acuity, corrected distance visual acuity (CDVA), corneal topography, and ocular aberrations were measured before and 6 months postoperatively. RESULTS: In the ASA group, the values of horizontal trefoil, vertical coma, horizontal coma, spherical aberrations, and total HOAs increased significantly after surgery (all P < 0.05). There were no significant differences in the vertical trefoil between the preoperative and 6-month postoperative periods. In the Triple-A group, there were no differences in vertical trefoil and horizontal trefoil values between the preoperative and 6-month postoperative periods. Compared with the preoperative values, vertical coma, horizontal coma, spherical aberrations, and total HOAs were significantly increased at 6 months after surgery (all P < 0.05). Compared to the Triple-A group, higher horizontal trefoil and horizontal coma were introduced in the ASA group at 6 months postoperatively. CONCLUSION: The Triple-A ablation profile of the MEL 90 excimer laser at a 500-Hz pulse rate was an efficient method to correct myopia, especially for mild-to-moderate myopia, compared with the aspheric ablation model, fewer horizontal trefoil and horizontal coma were induced at 6 months after LASEK. ABBREVIATIONS: HOAs, Higher-Order Aberrations; LASEK, laser subepithelial keratomileusis; ASA, Aberration Smart Ablation; UDVA, uncorrected distance visual acuity; CDVA, corrected distance visual acuity.

Predictors affecting myopic regression in - 6.0D to - 10.0D myopia after laser-assisted subepithelial keratomileusis and laser in situ keratomileusis flap creation with femtosecond laser-assisted or mechanical microkeratome-assisted.

PURPOSE: To investigate the predictive factors of postoperative myopic regression among subjects who have undergone laser-assisted subepithelial keratomileusis (LASEK), laser-assisted in situ keratomileusis (LASIK) flap created with a mechanical microkeratome (MM), and LASIK flap created with a femtosecond laser (FS). All recruited patients had a manifest spherical equivalence (SE) from - 6.0D to - 10.0D myopia. METHODS: This retrospective, observational case series study analyzed outcomes of refraction at 1 day, 1 week, and 1, 3, 6, and 12 months postoperatively. Predictors affecting myopic regression and other covariates were estimated with the Cox proportional hazards model for the three types of surgeries. RESULTS: The study enrolled 496 eyes in the LASEK group, 1054 eyes in the FS-LASIK group, and 910 eyes in the MM-LASIK group. At 12 months, from - 6.0D to - 10.0D myopia showed that the survival rates (no myopic regression) were 52.19%, 59.12%, and 58.79% in the MM-LASIK, FS-LASIK, and LASEK groups, respectively. Risk factors for myopic regression included thicker postoperative central corneal thickness (P ≦ 0.01), older age (P ≦ 0.01), aspherical ablation (P = 0.02), and larger transitional zone (TZ) (P = 0.03). Steeper corneal curvature (Kmax) (P = 0.01), thicker preoperative central corneal thickness (P < 0.01), smaller preoperative myopia (P < 0.01), longer duration of myopia (P = 0.02), with contact lens (P < 0.01), and larger optical zone (OZ) (P = 0.02) were protective factors. Among the three groups, the MM-LASIK had the highest risk of postoperative myopic regression (P < 0.01). CONCLUSIONS: The MM-LASIK group experienced the highest myopic regression, followed by the FS-LASIK and LASEK groups. Older age, aspheric ablation used, thicker postoperative central corneal thickness, and enlarging TZ contribute to myopic regression; steeper preoperative corneal curvature (Kmax), longer duration of myopia, with contact lens, thicker preoperative central corneal thickness, lower manifest refraction SE, and enlarging OZ prevent postoperative myopic regression in myopia from - 6.0D to - 10.0D.

Clinical observation on removing or reserving the epithelial flap in high myopia correction by LASEK / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM:To compare the clinical effects of removing or reserving the epithelial flap in high myopia correction by laser subepithelial keratomileusis(LASEK). <p>METHODS: Retrospective analysis of 58 patients(115 eyes)with high myopia received LASEK were selected and divided into reserving the epithelial flap group(30 patients, 59 eyes)and removing epithelial flap group(28 patients, 56 eyes)according to the order of the alternating vists. The changes of corneal irritation, epithelial healing time,uncorrected visual acuity and the occurrence of haze after surgery were observed.<p>RESULTS:Postoperative 1d, 2d, 3d, respectively, the pain score of the two groups were 1.64±0.64, 1.57±0.57; 0.83±0.49, 0.84±0.56; 0.36±0.48, 0.34±0.47, respectively, the differences were not significant(<i>P</i>>0.05). Postoperative 1wk, 1mo, 3mo, respectively, the uncorrected visual acuity of two group was 0.15±0.06, 0.12±0.05; 0.032±0.004, 0.041±0.003; 0.018±0.004, 0.022±0.005, and the differences were not significant(<i>P</i>>0.05). After 1mo, 3mo of surgery, the differences of the haze less than grade one of the two group, respectively, and were not significant(<i>P</i>>0.05), the differences of the haze of grade two of the two groups, respectively, and the differences were significant(<i>P</i><0.05). The epithelial healing time of the two groups were 4.22±0.30d, 3.89±0.32d(<i>P</i><0.05). The number of epithelial delayed healing of two groups was 0 eye and 10 eyes(<i>P</i><0.05).<p>CONCLUSION:It was similar both the changes of corneal irritation and uncorrected visual acuity of two groups,the rate of level two haze was higher in removing epithelial flap group. The time of healing of epithelium was quick than reserving the epithelial flap group,but the rate of delayed healing and poor healing of epithelium was higher than reserving the epithelial flap group. Therefore, for high myopia, it is worthy of clinical application of reserving the epithelial flap by LASEK.

Comparative study of wave-front aberration and corneal Asphericity after SMILE and LASEK for myopia: a short and long term study.

BACKGROUND: The study compares the wave-front aberration and corneal asphericity from multiple perspectives after Small Incision Lenticule Extraction and Laser-assisted Subepithelial Keratomileusis for mild to moderate myopia in a short and long time period. METHODS: This prospective and comparative study included 32 eyes in the SMILE group, with a mean spherical equivalent (SE) of - 4.1 ± 0.9D and 32 eyes in the LASEK group, with a mean SE of - 3.7 ± 1.0D. Visual acuity, refractive error, wave-front aberration, corneal Q value and corneal refractive power were analyzed pre-, 3 months and 3 years post-operatively. RESULTS: There was no significant difference in refractive error, wave-front aberration, corneal Q value and corneal refractive power before treatment. Three months postoperative, Q value within 6 mm (SMILE: 0.46 ± 0.27, LASEK: 0.63 ± 0.28, p = 0.02), the relative peripheral corneal power (5-8 mm: p < 0.05), change of higher order aberration (SMILE: 0.10 ± 0.16, LASEK: 0.24 ± 0.20, p = 0.004) and spherical aberration (SA, SMILE: -0.07 ± 0.30, LASEK: -0.41 ± 0.40, p < 0.001) were significantly lower in the SMILE than in LASEK group. The visual acuity, refractive error, coma, peripheral Q value, central corneal power had no significant difference between the two groups. Three years post-operation, the corneal power distribution results and SA were similar to that of 3-month, while the Q value had no significant difference between the two groups. CONCLUSION: In the early stage after SMILE, the HOAs was lower, the corneal refractive power from central to periphery was more uniform than after LASEK; and in the long-term run, SMILE still preceded LASEK in the corneal asphericity and aberration.

Comparison of the posterior corneal elevation and biomechanics after SMILE and LASEK for myopia: a short- and long-term observation.

PURPOSE: This study compares the posterior corneal elevation and corneal biomechanics after small incision lenticule extraction (SMILE) and laser-assisted subepithelial keratomileusis (LASEK) for myopia correction in a short- and long-term observation. METHODS: This prospective study included 32 patients in the SMILE group and 32 patients in the LASEK group. Corneal posterior central elevation (PCE), posterior mean elevation (PME), corneal back power (Kb), and anterior chamber depth (ACD) were evaluated with Pentacam, and intraocular pressure (IOP), corneal hysteresis (CH), and corneal resistance factor (CRF) were evaluated with the ORA at pre-operation and 3 months and 3 years post-operation. RESULTS: Three months post-operatively, CH, CRF, and IOP decreased significantly and central posterior surface shifted backward in both groups (p < 0.05). CH was lower in the LASEK group (p = 0.03) and change of CH and CRF per unit corneal tissue removed (ΔCH/ablation depth (AD) and ΔCRF/AD) was lower in SMILE than in LASEK (p = 0.01, 0.03). Three years post-operatively, the PME shifted more posteriorly in LASEK (p = 0.04), but was stable in SMILE (p = 0.06). Kb flattened and ACD was shallower in both groups (compared to preoperative data, p < 0.001). CH in the LASEK group increased and is comparable to that in the SMILE group at 3 years post-operative. CONCLUSION: Both SMILE and LASEK can change the posterior surface and corneal biomechanics. SMILE may have less influence on corneal biomechanics than LASEK at an early stage post-operative in terms of per unit corneal tissue removed, but the effect became comparable in a long-term observation.

Comparison of epithelial flap removed LASEK and femtosecond laser assisted LASIK in correction of low and moderate myopia / 天津医药

@#Objective To compare the therapeutic effect of epithelial flap removed laser subepithelial keratomileusis (LASEK) and femtosecond laser assisted LASIK (FS-LASIK) in the treatment of moderate and low myopia. Methods A total of 103 patients (103 eyes) of low and moderate myopia were selected, 51 patients (51 eyes) were treated with LASEK and 52 patients (52 eyes) were treated with FS-LASIK. Data of uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), residual equivalent spherical degree (SE), total high-order aberrations (HOAs), spherical aberration, coma and trefoil were examined before operation and 1month and 3 months after operation, and compared between two groups of patients. Results There were no significant differences in UCVA and BCVA 1 month and 3 months postoperatively between the two groups. SE shifted to myopia direction in LASEK group compared with that of FS-LASIK group 1 month postoperatively (P＜0.05), but reached a similar level 3 months after surgery. The HOAs and spherical aberration were significantly increased 1 month and 3 months postoperatively compared with those before operation in LASEK and FSLASIK groups (P＜0.05). Coma was significantly increased 1 month postoperatively in FS- LASIK group and returned to the preoperative level 3 months postoperatively, while it remained at baseline 1 month and 3 months postoperatively in the LASEK group. The HOAs and coma were significantly higher 1 month postoperatively in FS-LASIK group compared to those of LASEK group (P＜0.05), while they reached a similar level 3 months postoperatively. Conclusion The therapeutic effect of epithelial flap removed LASEK can reach a level equal to FS-LASIK at the early stage after surgery. It is a good selectable choice for patients with low to moderate myopia.

Quantitative analysis of residual ethanol content in corneal epithelium flaps in LASEK / 眼科新进展

Objective To detect and analyze of residual ethanol in abandoned flaps after laser subepithelial keratomileusis (LASEK) with ethanol infiltration methods.Methods Together 20 patients (40 eyes) undergoing LASEK were recruited in the study.After infiltrated with 20％ ethanol and rinsed in equilibration solution,the corneal epithelial free flap was isolated and removed in time for sealing,and then procedures were continuously completed.Finally,observation of the skin flap production,postoperative irritation symptoms,epithelial healing,visual recovery and postoperative haze situation was performed,and then the amount of ethanol in the epithelial flap was measured.Results There was no failure in making the intact corneal flaps.The sensory score of postoperative irritation was 2.52 ± 1.46.Neonatal epithelial with 1 grade was observed in 32 eyes,2 grade in 8 eyes 5 days after surgery,while corneal haze with 0.5 grade was occurred in 3 eyes,1 grade in 2 eyes 12 weeks after surgery.There were ethanol residues in corneal epithelium in the abandoned flaps,with the amount of ethanol residues of (0.205 2 ± 0.041 0) μL in each flap.Conclusion It is found that a certain amount of ethanol residue in the corneal epithelium after LASEK with ethanol infiltration equilibration solution rinse,which may be one reason of the corneal irritation symptoms and corneal haze.

Comparison on biomechanical stability between femtosecond laser assisted LASIK and LASEK with ocular response analyzer / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To compare the difference of biomechanical stability after a femtosecond laser-assisted <i>in situ</i> keratomileusis(FS-LASIK)and laser-assisted subepithelial keratomileusis(LASEK)by ocular response analyzer(ORA). <p>METHODS: This prospective study was conducted at the First Affiliated Hospital of Harbin Medical University, and myopic patients with the equivalent sphere between -2.00 and -5.00 diopters from January 2016 and December 2017 were enrolled. All the subjects were divided into FS-LASIK and LASEK group respectively according to different surgical methods. There were 64 patients(100 eyes)participated in the FS-LASIK group while 53 patients(100 eyes)in the LASEK surgery group. Corneal hysteresis value(CH)and corneal resistance factor value(CRF)were measured pre-, 1mo and 3mo postoperation of all the subjects. And the variance analysis of two groups was repeated to compare the overall difference between the two modes of operation from pre-operation to post operation. <p>RESULTS: The CH and CRF value of the two groups were different before and after operation(<i>P</i><0.05). The comparison results of repeated measurements showed that the CH value and CRF value of the surgical methods were reduced in 1 and 3mo after operation, respectively, and there was significance(<i>P</i><0.05). The CH and CRF of FS-LASIK group was lower than LASEK group only in 1mo after the operation(<i>P</i><0.05). <p>CONCLUSION: Both surgeries could affect the biomechanical stability of cornea. From the point of view of biomechanical stability, LASEK operation is safer than FS-LASIK operation and reduces the possibility of postoperative refractive regression.

Effects of mitomycin C at different exposure time on the morphology of corneal endothelial cells in LASEK surgery / 国际眼科杂志(Guoji Yanke Zazhi)

· AIM:To investigate the effects of mitomycin C (MMC) on corneal endothelial cells at different exposure time during laser-assisted subepithelial keratomileusis (LASEK).· METHODS:Patients who received LASEK were included and divided into Group T1 (15s≤t≤45s) and T2 (5s＜t≤70s) based on the exposure time of MMC with corneal stroma.Cell density (CD) of corneal endothelial cells in central and peripheral cornea,average cell area (ACA),area standard deviation (SD),coefficient of variation (CV) and percentage of hexagonal cells (HEX) before surgery and at 1wk,1,3 and 6mo after surgery were compared between and within the groups.· RESULTS:A total of 196 eyes of 98 patients were included with 98 eyes in Group T1 and 98 eyes in Group T2.With the exception of peripheral ACA,central CV and HEX in Group T1 and T2,which significantly changed at 1wk after the surgery (P＜0.05),there was no significant difference in central and peripheral parameters within both groups or between the groups (P ＞0.05).· CONCLUSION:Although transient acute changes in central CV and HEX and peripheral ACA were observed,there is no significant effect on the long-term corneal health status when MMC is applied in a reasonable time range in LASEK surgery.

Clinical observation on 1g/L bromfenac sodium hydrate ophthalmic solution associated with glucocorticoid in high myopia after LASEK / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To observe the efficacy and safety of 1g/L bromfenac sodium hydrate ophthalmic solution in the partial substitution of glucocorticoid after laser subepithelial keratomileusis (LASEK).METHODS: Totally 104 cases (208 eyes) were received LASEK, which were selected and divided into study group and control group.The study group were adopted 1g/L bromfenac sodium hydrate ophthalmic solution combined with tobramycin dexamethasone eye drops and fluorometholone eye drops, the control group were adopted tobramycin dexamethasone eye drops and fluorometholone eye drops.The changes of visual acuity and intraocular pressure of two groups were recorded before and after surgery, and the score of painness and the occurrence of haze were observed after surgery.RESULTS: At postoperative 1, 2, 3d, respectively, the pain score of the study group were 1.70±0.35, 1.25±0.34, 0.82±0.32, the pain score of the control group were 2.30±0.43, 1.68±0.44, 1.12±0.33, the differences were significant (P0.05), and the differences were not significant(P>0.05).At preoperative and postoperative 1, 2wk, 1 and 3mo of surgery, respectively, the intraocular pressure of study group were 17.33±1.58, 7.54±1.28, 7.23±1.58, 7.26±1.47, and 7.30±1.36 mmHg;the intraocular pressure of control group were 17.53±1.43,7.57±1.32,7.73±1.55,7.80±1.38,7.86±1.43 mmHg,the differences were not significant between before and at 2wk after surgery(P>0.05), the differences were significant between the two groups at 2wk, 1mo and 3mo (P0.05).CONCLUSION: It is safe and effective that 1g/L bromfenac sodium hydrate ophthalmic solution in the partial substitution of glucocorticoid after laser subepithelial keratomileusis.The patient has a lower intraocular pressure, has similar therapeutic effect as glucocorticoid in vision and antiinflammatory.

Implantable collamer lens for residual refractive error after corneal refractive surgery.

AIM: To assess the safety, efficacy, predictability and stability of implantable collamer lens (ICL) for residual refractive error after corneal refractive surgery. METHODS: This study evaluated 19 eyes of 12 patients who underwent ICL implantation after corneal refractive surgeries. They were followed up for 1y to 5y of uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refractive error, flat and steep K value, axial length, intraocular pressure, corneal endothelial cell density, adverse events after ICL surgery. RESULTS: The mean follow-up period was 39.05±19.22 mo (range, 1-5y). Spherical equivalent refractive error changed from -7.45±3.02 D preoperatively to -0.85±1.10 D 1wk to 1mo after ICL implantation, with the safety and efficacy indices being 1.12 and 1.15, respectively. A total of 52.63% of eyes were within ±0.5 D of the predicted spherical equivalents, 73.68% were within ±1.0 D. A trend of mild regression towards myopia with axial elongation after 5y was observed. One eye with mild anterior capsule opacity and retinal detachment 1y after surgery were observed. CONCLUSION: ICL implantation is safe and effective for the correction of residual refractive error after corneal refractive surgeries, especially in moderate to high residual myopia.

Comparison of biomechanical effects of small incision lenticule extraction and laser-assisted subepithelial keratomileusis.

PURPOSE: To compare the corneal biomechanical properties after small incision lenticule extraction (SMILE) group and laser-assisted subepithelial keratomileusis (LASEK) group. METHODS: The SMILE group comprised 39 patients (75 eyes) while it was 38 patients (76 eyes) in the LASEK group. Corneal hysteresis (CH) and the corneal resistance factor (CRF) parameters were determined using the Ocular Response Analyzer preoperatively and at 1 and 3 months postoperatively. RESULTS: There were significant differences in the preoperative manifest refraction spherical equivalent (MRSE), central corneal thickness (CCT), the planned ablation depth (AD) or CRF values between the two groups, except for the CH value (p = 0.07). The CH and CRF values at 1 and 3 months postoperatively were significantly lower than the preoperative values in both groups (p < 0.01). The postoperative CH values were significantly lower in the LASEK group than in the SMILE group at both follow-up visits after adjusting for age, sex, preoperative CCT, preoperative SE, planned AD and the use of both eyes in the same subject (p < 0.01). However, no significant differences were observed in postoperative CRF between groups (p = 0.22 at 1 month and p = 0.41 at 3 months). No significant correlation was found between the planned AD and the changes in CH or CRF at any follow-up visit in the SMILE group. The preoperative magnitude of CH and CRF may be predictors of postoperative changes in CH and CRF in the both groups. CONCLUSIONS: CH and CRF decreased after SMILE and LASEK. However, the changes in the CH values were less after SMILE than after LASEK.

Effect and safety of applying mitomycin C in laser - assisted subepithelial keratomileusis for extreme high myopia / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To observe the effect and safety of applying mitomycin C ( MMC ) in laser - assisted subepithelial keratomileusis ( LASEK) for extreme high myopia. ●METHODS:LASEK with 0. 02% MMC was performed in 364 eyes of 182 patients with extreme high myopia and spherical equivalent was-9. 0 to-10. 25 D. All the patients were divided into four groups according to the applying time of MMC. The time in Group l was 10s, in GroupⅡwas 25s, in Group Ⅲ was 40s and 55s in Group lV. Uncorrected visual acuity ( UCVA ) , residual refraction, Haze, healing time of corneal epithelium, density and variant index of corneal endothelium was examined in these patients and follow-up 6mo. ●RESULTS:At 6mo after surgery, 76. 3%, 94. 0%, 92. 3%and 93. 8% of the patients in Group l, GroupⅡ, GroupⅢ and Group lV respectively achieved the UCVA better than 15/20. There was significant difference of UCVA between Group l and the other three groups (χ2=19. 610, P=0. 000). Proportion of the residual refraction between ± 0. 5D in Group l (78. 8%) was lower than other groups (95. 2% in Group Ⅱ, 93. 3% in Group Ⅲ, and 92. 7% in GroupⅣ) at 6mo and there was significant difference (χ2=16. 329, P=0. 001). Group l had more Haze statistically than the other three groups at 6mo postoperatively ( Hc=50. 110, P=0. 000). The healing time of cornea epithelium seem to be no statistically difference between each group at 6mo (χ2=11. 611, P>0. 05). MMC had no influence on the density of corneal endothelium in each group postoperatively (P>0. 05), there were 3071. 3±284. 4 cells/mm2 in Group l, 3 105. 6 ± 337. 8 cells/mm2 in Group Ⅱ, 2 986. 3 ± 304. 1cells/mm2 in Group Ⅲ and 3 088. 7 ± 372. 5 cells/mm2 in Group lV respectively. The variant index of corneal endothelium calculated in each group at 6mo after surgery was 24. 72 ± 6. 52, 22. 93 ± 6. 74, 24. 38 ± 6. 63 and 23. 14±7. 22 repectively, compare with that preoperatively there were no statistically differences (P>0. 05). ●CONCLUSION: For extreme high myopia LASEK with 0. 02% MMC is effective and safe. The MMC applying time of 25s in LASEK can effectively reduce Haze after surgery and decrease potential complications.

Comparation of effectiveness of silicone hydrogel contact lens and hydrogel contact lens in patients after LASEK.

AIM: To conduct a comparative study of effectiveness of silicone hydrogel contact lens and hydrogel contact lens, which are used in patients after laser-assisted subepithelial keratomileusis (LASEK). METHODS: Sixty-three patients (121 eyes) with a spherical equivalent ≤-5.0 D were chosen after undergoing LASEK in 2012 at Guangdong General Hospital. They were randomly divided into 2 groups. The silicone hydrogel group included 32 cases (61 eyes) that wore silicone hydrogel contact lenses for 4-6d after the operation, while the hydrogel group included 31 cases (60 eyes) who wore hydrogel contact lenses for 4-6d after the operation. Patients' self-reported postoperative symptoms (including pain, photophobia, tears, and foreign body sensation) were evaluated. The healing time of the corneal epithelium, the visual acuity of patients without contact lens after epithelial healing, and the incidence of delayed corneal epithelial shedding were also assessed. The follow-up time was 1mo. RESULTS: Postoperative symptoms were milder in the silicone hydrogel group than in the hydrogel group. There were significant differences in pain, foreign body sensation, and photophobia between the 2 groups (P<0.05), although there was no significant difference in postoperative tearing (P>0.05). The healing time of the corneal epithelium in the silicone hydrogel lens group was markedly shorter than that in the hydrogel group (4.07±0.25 vs 4.33±0.82d, t=2.43, P=0.02). Visual acuity without contact lenses after healing of the corneal epithelium was better in the silicone hydrogel group compared with the hydrogel group (χ (2)=7.76, P=0.02). There was no significant difference in the occurrence of delayed corneal epithelial shedding between the 2 groups (P>0.05). CONCLUSION: Patients with LASEK using silicon hydrogel contact lenses had less discomfort and shorter corneal epithelial healing time compared with those using hydrogel contact lenses, suggesting that silicon hydrogel contact lenses may be considered to be a better choice of bandage contact lens after LASEK.

Impact of long-term soft contact lens wear on epithelial flap production and postoperative recovery in laser-assisted subepithelial keratomileusis.

PURPOSE: To investigate the impact and postoperative clinical recovery of long-term soft contact lens wear on the epithelial flap made during laser-assisted subepithelial keratomileusis (LASEK). METHODS: In a prospective study, 371 patients (589 eyes) who underwent LASEK were divided into four groups (G1, G2, G3, G4) according to their length of soft contact lens wear. After the contact lens (CL) was removed 1 week after surgery, various symptoms - uncorrected visual acuity (UCVA), oedema of the corneal epithelium, spherical equivalent (SE) and haze degree - were recorded on day 1, and at 1 and 3 months postoperatively. RESULTS: There were no significant differences in corneal flap production among the first three groups that wore CLs, but various symptoms and UCVA were all different from the fourth group that did not wear CLs. There were statistically significant differences in oedema of corneal epithelium among the first three groups, and the degree of oedema was positively correlated with the CL wearing time. There were no significant differences in postoperative SE and haze in all four groups. CONCLUSIONS: Long-term soft CL wear can affect production of the epithelial flap and postoperative recovery, including various symptoms, oedema of the central corneal epithelium and visual acuity. In contrast, there was no effect of long-term CL wear on postoperative mean refractive spherical equivalent (MRSE) and haze.