Comparison of corneal refractive power and visual quality after LASEK, TransPRK or FS-LASIK / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To compare the corneal refractive power and visual quality after three kinds of corneal refractive surgery: laser subepithelial keratomileusis(LASEK), transepithelial photorefractive keratectomy(TransPRK)and femtosecond laser assisted in situ keratomileusis(FS-LASIK).METHODS: Retrospective study. A total of 232 patients(464 eyes)who underwent elective corneal refractive surgery in our hospital from January 2021 to December 2022 were selected as the study subjects. They were divided into the LASEK group of 70 cases(140 eyes), TransPRK group of 76 cases(152 eyes), and FS-LASIK group of 86 cases(172 eyes)according to the different surgical choices made by the patients. Uncorrected visual acuity(UCVA), visual quality, biomechanical stability, tear film break-up time(BUT), Schirmer Ⅰ test(SⅠt)and quality of life were compared among the three groups at 1 and 3 mo postoperatively.RESULTS: The UCVA of the three groups significantly improved at 1 and 3 mo postoperatively, the total high-order aberrations, spherical aberration, horizontal coma, and vertical coma of the entire cornea were significantly increased, while the biomechanical stability in all three groups were significantly reduced(all P<0.05). At 3 mo postoperatively, the biomechanical stability in the TransPRK and LASEK groups were higher than those of the FS-LASIK group(all P<0.05), and the TransPRK group had higher quality of life scores than the LASEK group and FS-LASIK group(P<0.05). Furthermore, there was no significant difference in preoperative or postoperative BUT and SⅠt among the three groups(all P>0.05).CONCLUSION:In the treatment of ametropia, LASEK, TransPRK and FS-LASIK all have certain effects, and have similar results in improving UCVA and increasing visual quality. However, TransPRK and LASEK have more stable biomechanical properties than FS-LASIK, and have better efficacy in improving patients' quality of life.

Changes in corneal epithelial thickness and optical density and their correlation after smart pulse technology-assisted transepithelial photorefractive keratectomy / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To evaluate the changes in corneal epithelial thickness(CET)and corneal optical density(CD)after smart pulse technology(SPT)-assisted transepithelial photorefractive keratectomy(TPRK)and analyze their correlation.METHODS: The prospective study included 60 patients(120 eyes)with myopia and myopic astigmatism who underwent SPT-TPRK in the ophthalmology department at the First Affiliated Hospital of Xinxiang Medical University between February and August 2023. Changes in CET and CD were evaluated preoperatively and at 1 wk, 1 and 3 mo postoperatively.RESULTS: A total of 14 cases(28 eyes)were lost to follow-up, and 3 patients(6 eyes)with postoperative haze were excluded from this study, resulting in a final inclusion of 43 patients(86 eyes). At 1 wk after SPT-TPRK, CET had statistically significantly thickened compared to preoperative levels(P<0.05), particularly in the CET at 0-2 mm central corneal area(P<0.05). At 1 mo after SPT-TPRK, the CET at 0-2 mm area had statistically significantly decreased(P<0.05). At 3 mo after SPT-TPRK, the CET at 0-2 mm had essentially reached preoperative levels. Postoperative CD values increased, with a positive correlation between CET in the 0-2 mm area and CD in the whole 0-2 mm area(r=0.256, P<0.05), and a positive correlation between CET in the 2-5 mm area and CD in the anterior 2-6 mm area(r=0.319, P<0.05).CONCLUSION: Corneal epithelial remodeling takes 3 mo in areas within 2 mm of the central cornea; areas with thinner CET have faster postoperative corneal epithelial remodeling and greater thickening in the early postoperative period; CD increases in the early postoperative period compared to the preoperative value, and in some areas, there is a positive correlation between CET and CD value.

Efficacy and safety of transepithelial photorefractive keratectomy combined with accelerated corneal cross-linking for refractive error in thin or irregular cornea / 中华实验眼科杂志

Objective:To evaluate the efficacy and safety of transepithelial photorefractive keratectomy (Trans-PRK) combined with accelerated corneal cross-linking (CXL) for refractive error in patients with thin or irregular corneas, excluding keratoconus.Methods:An observational case series study was performed.Fifty-five right eyes of 55 myopic patients diagnosed with thin or irregular corneas, who underwent Trans-PRK combined with prophylactic CXL surgery, were included at Baotou Chaoju Eye Ophthalmic Hospital from August 2017 to July 2018.Uncorrected distance visual acuity (UDVA) of the operated eye was measured using international standard visual acuity charts, and refractive diopters were measured by computer and comprehensive refraction before surgery and at 1 week, 1, 3, 6, and 12 months after surgery.Corneal morphology was assessed with the Pentacam anterior segment analyzer before surgery and at 3, 6, and 12 months after surgery.Intraocular pressure (IOP) was measured with a non-contact tonometer before surgery and at 1, 3, 6, and 12 months after surgery.The incidence of postoperative complications was recorded.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Baotou Chaoju Ophthalmic Hospital (No.btcj-u-1). Written informed consent was obtained from each subject.Results:Preoperative, 1-week, 1-, 3-, 6-, and 12-month postoperative UDVA (LogMAR) were 0.52(0.55, 0.78), 0.22(0.12, 0.17), 0.10(0.04, 0.07), 0.00(-0.04, -0.16), -0.08(-0.05, -0.03) and -0.08(-0.06, -0.04), respectively, showing a statistically significant overall difference ( Z=249.44, P<0.001). UDVA at each postoperative time point was improved compared to preoperative, and UDVA at 3, 6, and 12 months postoperatively was significantly improved compared to 1 week and 1 month postoperatively (all at P<0.001). The spherical diopter at each postoperative time point decreased significantly compared to preoperative, with the spherical diopter at 1, 3, 6, and 12 months postoperatively being lower than that at 1 week postoperatively, and the 12-month postoperative spherical diopter being lower than that at 3 and 6 months postoperatively, showing statistically significant differences (all at P<0.001). The cylindrical degree at 1, 3, 6, and 12 months postoperatively was lower than that at preoperative and 1 week postoperatively, with statistically significant differences (all at P<0.05). After the operation, the spherical equivalent of the operated eye gradually decreased with time, tending toward emmetropia.The spherical equivalent at each postoperative time point decreased compared to preoperative, with the spherical equivalent at 1, 3, 6, and 12 months postoperatively being lower than that at 1 week postoperatively, and the spherical equivalent at 12 months postoperatively being lower than that at 3 and 6 months postoperatively, showing statistically significant differences (all at P<0.001). The corneal K1 and K2 values at 3, 6, and 12 months postoperatively were significantly lower than preoperatively (all at P<0.001), and the corneal K1 and K2 values at 3 months postoperatively tended to stabilize.The IOP of the operated eye at 3, 6, and 12 months postoperatively was significantly lower than preoperatively, and the IOP at 6 and 12 months postoperatively was lower than that at 1 and 3 months postoperatively, with statistically significant differences (all at P<0.001). One eye developed grade 0.5 corneal haze at 1 week postoperatively, which spontaneously resolved to transparency at 1 month postoperatively. Conclusions:Trans-PRK combined with accelerated CXL has good efficacy, stability and safety for refractive error patients with thin or irregular corneas, except for keratoconus.

Effect of small incision lenticule extraction on the treatment of myopia patients and the impact on corneal biomechanics / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To investigate the effect of small incision lenticule extraction(SMILE)on the treatment of myopia patients, and the impact on corneal biomechanics.METHODS:Retrospective study. A total of 120 myopic patients(240 eyes)who were scheduled to undergo corneal refractive surgery in Anyang Eye Hospital from January 2020 to December 2021 were selected. The patients were divided into SMILE group(64 patients, 128 eyes)and transepithelial photorefractive keratectomy(TransPRK)group(56 patients, 112 eyes)according to the surgical treatment method. The two groups were compared in terms of uncorrected visual acuity, corneal biomechanics, corneal endothelial cell count, posterior corneal surface height and corneal surface regularity index at 1, 7 d, 1, 3, 6 mo and 1 a after surgery, and surgical complications.RESULTS:The uncorrected visual acuity of the SMILE group at 1, 7 d and 1 mo after surgery was better than that of the TransPRK group(all P&#x003C;0.001), but there was no statistically significant difference between the groups at 3, 6 mo and 1 a after surgery(all P&#x003E;0.05). Compared with preoperative values, corneal-compensated intraocular pressure, Goldmann-correlated intraocular pressure, corneal resistance factor, and corneal hysteresis in both groups showed a first decreasing and then increasing trend after surgery. The corneal-compensated intraocular pressure, Goldmann-correlated intraocular pressure, corneal resistance factor, and corneal hysteresis in the SMILE group at 1, 7 d and 1 mo after surgery were higher than those in the TransPRK group(all P&#x003C;0.05), but there was no statistically significant difference between the groups at 3, 6 mo and 1 a after surgery(all P&#x003E;0.05). There were no significant changes of corneal endothelial cell count and corneal posterior surface height in the two groups after surgery(all P&#x003E;0.05). Furthermore, corneal surface regularity index of the two groups showed a first increasing and then decreasing trend after surgery, with no statistically significant difference between the groups(P&#x003E;0.05), and there was no statistically significant difference in the incidence of postoperative complications between the groups(P&#x003E;0.05).CONCLUSION:Compared with TransPRK, SMILE has less influence on corneal biomechanics, and better visual recovery in the early stage. There is no difference in long-term visual acuity between the two surgeries, and both have good safety and effectiveness.

Corneal ectasia following photorefractive keratectomy: a confocal microscopic case report and literature review / Ectasia corneana após ceratectomia fotorrefrativa: relato de caso de microscopia confocal e revisão da literatura

ABSTRACT The occurrence of corneal ectasia after photorefractive keratectomy is a rare but serious complication of refractive surgery. Possible risk factors are not well assessed, but a probable reason is the failure to detect keratoconus preoperatively. In this report, we describe a case of corneal ectasia after photorefractive keratectomy in a patient who presented a suspicious tomography pattern preoperatively but had no degenerative alterations associated with pathologic keratoconus, as revealed by in vivo corneal confocal microscopy. We also review eligible case reports of post-photorefractive keratectomy ectasia to find similar characteristics.

RESUMO A ocorrência de ectasia corneana após ceratectomia fotorrefrativa é uma complicação rara, porém grave, em cirurgia refrativa. Os possíveis fatores de risco não são bem avaliados, mas a opinião atual é que a falha na detecção de ceratocone pré-operatório possa ser o principal motivo. Neste relato, descrevemos um caso de ectasia corneana após ceratectomia fotorrefrativa em paciente apresentando padrão tomográfico suspeito no pré-operatório, mas sem alterações degenerativas associadas a ceratocone patológico, conforme revelado por microscopia confocal in vivo da córnea. Além disso, revisamos, na literatura, relatos de casos elegíveis de ectasia pós-ceratectomia fotorrefrativa para encontrar características semelhantes.

The association of pre-photorefractive keratectomy Schirmer-1 test value with postoperative corneal epithelial thickness, ocular surface discomfort, and visual acuity

ABSTRACT Purpose: To investigate the association of pre--photorefractive keratectomy Schirmer-1 test value with post--photorefractive keratectomy central corneal epithelial thickness, ocular surface disease index score, and uncorrected distance visual acuity. Methods: Patients were categorized according to preoperative Schirmer-1 value: the normal Schirmer Group (n=54; Schirmer-1 test value, >10 mm) and the low Schirmer Group (n=52; Schirmer-1 test value, between 6 and 10 mm). We analyzed ablation depth, visual acuity, result of Schirmer-1 test (with anesthesia), tear film break-up time, ocular surface disease index score, central corneal epithelial thickness, and spherical equivalent refraction. Results: We found significant differences between the groups in Schirmer-1 test value, tear film break-up time, and ocular surface disease index score, both preoperatively and postoperatively (p<0.001). The preoperative central corneal epithelial thicknesses of the two groups were similar (p>0.05). After photorefractive keratectomy, the Schirmer-1 test value and spherical equivalent refraction decreased in both groups (p<0.05), and ocular surface disease index scores and central corneal epithelial thickness values increased in the low Schirmer Group (p<0.001) but not in the normal Schirmer Group (p>0.05). The postoperative central corneal epithelial thicknesses of the low Schirmer Group were significantly higher than those of the normal Schirmer Group (p<0.001). Postoperative uncorrected distance visual acuity did not differ significantly between the two groups (p>0.05). Conclusions: In patients with low Schirmer-1 test values before photorefractive keratectomy, the corneal epithelium thickened and ocular surface complaints increased during the postoperative period. However, changes in the corneal epithelium did not affect the postoperative uncorrected distance visual acuity. To reduce postoperative problems on the ocular surface in these patients, we recommend that dry eye be treated before photorefractive keratectomy.

Ten-year follow-up of corneal cross-linking and refractive surface ablation in patients with asymmetric corneal topography

Purpose: Compare the safety and efficacy of wavefront?guided photorefractive keratotomy (PRK) 6 months after cross?linking (CXL) to wavefront?guided PRK alone for refractive correction in patients with bilateral asymmetric corneal topography. Methods: Prospective randomized clinical trial with 16 patients (32 eyes). CXL with subsequent PRK after 6 months in one eye, and PRK alone was performed in contralateral eyes. The follow?up was 10 years. We analyzed visual outcomes, Scheimpflug topography, and corneal haze evaluation. Results: Eyes in the PRK group showed better results than in the CXL + PRK group. Mean postoperative CDVA was 0.044 logmar (SD, 0.073) in the PRK group and 0.1 logmar (SD, 0.21) in the CXL + PRK group, the mean sphere was + 0.21 (SD, 0.6) D in the PRK group and 0.87 (SD, 2.3) D in the CXL + PRK group, and mean SE was ?0.35 (SD, 0.65) D in the PRK group and 0.62 (SD, 2.32) D in the CXL + PRK group. In one patient, a steepening of 2.5 D and a thinning of 17 ?m occurred in PRK alone group. Two patients in the CXL + PRK group presented corneal haze. The overall complication rate was 18,75% (haze and ectasia). Conclusion: Non?simultaneous CXL and PRK procedures yielded good refractive results, but worse than those obtained with PRK alone. Although one patient in the PRK group developed corneal ectasia, the CXL + PRK group had a higher loss of vision lines, indicating less safety

Phototherapeutic keratectomy: current approaches and changing trends in a tertiary eye clinic / Ceratectomia fototerapêutica: abordagens atuais e tendências de mudança em uma clínica oftalmológica terciária

ABSTRACT Purpose: To examine the efficacy of phototherapeutic keratectomy as a treatment for variable pathologies with anterior corneal opacities and evaluate the distribution of phototherapeutic keratectomy indications over the past 10 years. Methods: The records of 334 eyes from 276 patients who underwent phototherapeutic keratectomy between March 2010 and 2020 were retrospectively reviewed. Etiologies of the patients who underwent phototherapeutic keratectomy were noted, and their changes were examined. Refractive and visual acuity results before and after the operation were recorded and analyzed according to etiology. Results: The mean age of the patients was 40.7 ± 16.2 years (range: 19-84). The mean follow-up was 25.5 ± 19.1 months (range: 3-96). Phototherapeutic keratectomy was most frequently applied for corneal stromal dystrophies (44%, 151 eyes from 111 patients), and granular dystrophy was the most common phototherapeutic keratectomy indication among corneal dystrophies. Unlike other indications, there has been an increase in the application of phototherapeutic keratectomy for persistent subepithelial opacities due to adenoviral conjunctivitis in the past 10 years. There was a significant increase in visual acuity in all groups except for the recurrent epithelial defect group (p<0.05). The greatest improvement in visual acuity was detected for stromal dystrophies in the granular dystrophy subgroup. Conclusion: Despite changing indication trends, phototherapeutic keratectomy remains an effective and reliable treatment for anterior corneal lesions.

RESUMO Objetivo: Examinar a eficácia da ceratectomia fo­toterapêutica para o tratamento de patologias variáveis que apresentarem opacidades anteriores da córnea, e avaliar a distribuição das indicações de ceratectomia fototerapêutica nos últimos 10 anos. Métodos: Foram revisados retrospectivamente os prontuários de 276 pacientes, com 334 olhos tratados com ceratectomia fototerapêutica entre março de 2010 e o ano de 2020. As etiologias dos pacientes submetidos à ceratectomia fototerapêutica foram anotadas e suas alterações foram examinadas. Os resultados refrativos e de acuidade visual antes e após a operação foram registrados e analisados de acordo com a etiologia. Resultados: A idade média dos pacientes foi de 40,7 ± 16,2 anos (faixa: 19-84). O tempo médio de acompanhamento foi de 25,5 ± 19,1 meses (faixa: 3-96). A ceratectomia fototerapêutica foi aplicada com mais frequência para distrofias estromais corneanas (44%, 151 olhos de 111 pacientes); entre as distrofias corneanas como um todo, a distrofia granular foi a indicação terapêutica mais comum desse procedimento. Ao contrário de outras indicações, nos últimos 10 anos houve um aumento na aplicação de ceratectomia fototerapêutica em casos de opacidade subepitelial persistente causada por conjuntivite adenoviral. Houve um aumento significativo na acuidade visual em todos os grupos, exceto para o grupo com defeito epitelial recorrente (p<0,05). A maior melhora na acuidade visual foi detectada em casos de distrofia estromal, no subgrupo das distrofias granulares. Conclusão: Apesar das mudanças nas tendências de indicação, a ceratectomia fototerapêutica continua sendo uma abordagem terapêutica eficaz e confiável para tratar lesões da córnea anterior.

Cold bandage contact lens use reduces post-photorefractive keratectomy or corneal collagen-crosslinking pain perception in patients

Purpose: To compare post?operative pain perception using bandage contact lens (BCL) stored at 2–8?C (Cold BCL, CL?BCL) or room temperature (23 – 25?C, RT?BCL) after photorefractive keratectomy (PRK) or corneal collagen?crosslinking (CXL) and determine status of nociception associated factors. Methods: In this prospective interventional study, 56 patients undergoing PRK for refractive correction and 100 keratoconus (KC) undergoing CXL were recruited following approval from the institutional ethics committee with informed consent. Patients undergoing bilateral PRK received RT?BCL on one eye and CL?BCL on the other. Pain was graded by Wong–Baker scoring on the first post?operative day (PoD1). Expression of transient receptor potential channels (TRPV1, TRPA1, TRPM8), calcitonin gene?related peptide (CGRP) and IL?6 was measured in cellular content from used BCLs collected on PoD1. Equal number of KC patients received RT?BCL or CL?BCL post?CXL. Pain was graded by Wong–Baker scoring on PoD1. Results: Pain scores on PoD1 were significantly (P < 0.0001) reduced in subjects receiving CL?BCL (Mean ± SD: 2.6 ± 2.1) compared to RT?BCL (6.0 ± 2.4) post?PRK. 80.4% of subjects reported reduced pain scores with CL?BCL. 19.6% reported no change or increased pain scores with CL?BCL. TRPM8 expression was significantly (P < 0.05) increased in BCL of subjects reporting reduced pain with CL?BCL compared to those who did not. Pain scores on PoD1 were significantly (P < 0.0001) reduced in subjects receiving CL?BCL (3.2 ± 2.1) compared to RT?BCL (7.2 ± 1.8) post?CXL. Conclusion: The simple approach of using a cold BCL post?operatively substantially reduced pain perception and could overcome post?operative pain?related limited acceptance of PRK/CXL.

Clinical outcomes of epithelial ingrowth following laser in situ keratomileusis with mechanical debridement and compressed heating air flow: a case series / Resultado visual do tratamento do crescimento epitelial após laser in situ ceratomileuse através da remoção mecânica e aplicação de ar comprimido aquecido: série de casos

ABSTRACT Purpose: To describe the clinical outcomes of manual scraping of epithelial ingrowth followed by compressed heating air flow after laser in situ keratomileusis (LASIK). Methods: We underwent a retrospective, noncomparative, and interventional case series. Twenty eyes of 17 patients were included in this study. Each patient with a history of LASIK underwent epithelial removal with mechanical debridement followed by compressed heating air flow. Our primary outcome was the recurrence of epithelial ingrowth after 3 months of follow-up, while our secondary outcomes were uncorrected distance visual acuity, corrected distance visual acuity, and complications after surgery. Results: Ten patients (58.8%) were male, and eight eyes of seven (41.2%) patients underwent primary LASIK surgery, while12 eyes of 10 patients had flap-lift retreatment LASIK; sixteen eyes (80.0%) underwent mechanical microkeratome LASIK and four (20.0%) underwent femtosecond laser-assisted LASIK. Mean age at surgical removal of epithelial ingrowth was 37.0 years ± 9.3 years (range 24 to 55 years). There was recurrence of ingrowth in two eyes (10%) after 3 months of follow-up. The mean corrected distance visual acuity of patients before surgery was 0.07 ± 0.09 logMAR, and after the last follow-up was 0.02 ± 0.04 logMAR (p=0.06). The odds ratio of presenting with epithelial ingrowth after LASIK enhancement compared to primary LASIK was 29.41. Conclusion: Manual scraping followed by compressed heating air flow is a safe and effective treatment of clinically significant epithelial ingrowth after LASIK. At the last follow-up, no eye lost any line in corrected distance visual acuity.

RESUMO Objetivo: Descrever os resultados clínicos do tratamento do crescimento epitelial através da técnica de remoção manual seguido da utilização de um compressor de ar comprimido aquecido após a cirurgia de laser in situ keratomileusis (LASIK). Métodos: Vinte olhos de 17 pacientes foram incluídos no estudo. Cada paciente havia sido submetido a cirurgia de LASIK com presença de crescimento epitelial e foi submetido a tratamento cirúrgico para sua retirada. O objetivo primário foi identificar a presença de crescimento epitelial recorrente ao final de 3 meses de seguimento. Os objetivos secundários foram as medidas de acuidade visual sem correção, acuidade visual com correção, e complicações pós-operatórias. Resultados: Dez pacientes (58,8%) eram homens e 7 mulheres. Oito olhos de sete (41,2%) pacientes apresentavam cirurgia de LASIK primária e 12 olhos de 10 pacientes tinham cirurgia de LASIK com retratamento; dezesseis olhos (80%) utilizaram microcerátomo manual e quatro (20%) laser de femtosegundo. A média de idade no momento da cirurgia de remoção do epitélio era de 37,0 anos ± 9,3 (DP) (variando de 24 a 55 anos). Ocorreu recidiva do crescimento epithelial em dois olhos (10%) após 3 meses de seguimento. A acuidade visual sem correção antes da cirurgia era de 0,07 ± 0,09 logMAR, e após a cirurgia passou para 0,02 ± 0,04 logMAR (p=0,06). A chance (odds ration) de aparecimento do crescimento epithelial após uma reoperação de LASIK é 29,41 vezes maior do que no LASIK primário. Conclusão: A técnica de remoção epitelial manual seguida da utilização de ar comprimido aquecido é segura e efetiva no tratamento do crescimento epitelial após LASIK. Ao final do último acompanhamento, nenhum olho apresentou perda de linhas de visão.

Determination of the repeatability of corneal densitometry as measured with a Scheimpflug camera device in refractive surgery candidates

Purpose: Corneal densitometry analysis provides an objective measurement of corneal transparency in patients undergoing photorefractive keratectomy (PRK). To date, no study that focuses on determining the reliability and smallest real difference (SRD), specifically in PRK candidates, has been published. Methods: The study was conducted at Clínica de Oftalmología Sandiego, Medellín, Colombia. This was a prospective and analytical study. Refractive surgery candidates underwent Pentacam measurements twice with five minutes of difference. Repeatability of measurements was evaluated for every area using Wilcoxon signed?rank test, Spearman’s rank?order correlation, and the intraclass correlation coefficient, followed by a within?subjects factor (Sw) finishing with a determination of the SRD for all areas. Bland–Altman plots were created and analyzed. Results: A total of 110 eyes were included. The mean total densitometry was 18.67 ± 1.56 grayscale units (GSU) and 18.65 ± 1.49 GSU for the first and second measurements, respectively. Wilcoxon was non?significant (P > 0.05) while the intraclass correlation coefficient demonstrated an excellent agreement. SRD ranged from 0.21 GSU (posterior × 6–10 mm) to 1.79 GSU (total × 10–12 mm). Anterior depths and 10–12 mm annulus had consistently more variability and greater (worse) SRD. The 10–12 mm annulus showed great dispersion on the Bland–Altman plots. Conclusion: Corneal densitometry has an excellent repeatability in refractive surgery candidates for areas below 10 mm. Any densitometry change ?1.0 GSU in areas under 10 mm should be considered as well above measurement noise and corresponding to a real change in measured parameters. The 10–12 mm area does not seem to be reliable enough in refractive surgery candidates to warrant surveillance after corneal?based surgery

Keratorefractive surgery practice in a tertiary eye care center in central India / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To study the patient characteristics and keratorefractive surgery(KRS)practice in central India.METHOD: The retrospective study was conducted on 410 patients who underwent KRS from June 2017 to April 2022 at a tertiary eye care center in central India. Demographic data of the patients presenting for the spectacle free vision like age, sex, residence in the form of urban or rural area, refractive error, cause for spectacle-free vision, best-corrected visual acuity, types of procedure, postoperative follow-up and complications were recorded.RESULTS: Among the 410 patients who presented for spectacle-free vision, 324 patients were considered for KRS(79.0%), and 200 patients(61.7%)underwent the laser-assisted in situ keratomileusis(LASIK)procedure, whereas 124 patients(38.3%)underwent the photorefractive keratectomy(PRK)procedure. The final study group comprised 179 female and 145 male. The mean age of the patients was(25±3.5)years. A majority of patients were from urban areas(n=250, 77.2%). The mean preoperative manifest refraction in the right and left eyes was -4.5±2.1 and -4.9±2.0, respectively. The mean surgical time in the LASIK patient was(15±2)min and(17±3)min for both eyes in PRK. None of the patients exhibited epithelial ingrowth, flap healing complications, or infection, and none of them required enhancement. Suboptimal corneal thickness(n=28, 32.6%)was the most common reason for rejection. At the end of the 1-year follow up, 3 patients who underwent the LASIK procedure exhibited regression(-0.5 D±1 D), with a refractive error correction of -6.75 D, -8.5 D, and -7.0 D, respectively.CONCLUSION: LASIK is the predominant procedure for the correction of refractive error in the central Indian population. Although the number of PRK procedures was small, both LASIK and PRK exhibited excellent visual outcome. Myopic regression should be considered when choosing LASIK for high myopia.

Epithelial basement membrane dystrophy and cataract surgery / 国际眼科杂志(Guoji Yanke Zazhi)

Epithelial basement membrane dystrophy(EBMD)is a common anterior corneal dystrophy with hidden and easily missed clinical manifestations. Patients usually complain of mild blurred vision or foreign body sensation, or occasional pain at night or immediately after opening the eyelid in the morning. Slit-lamp examination revealed irregular, amorphous corneal surfaces, fingerprint-like linear lesions, and punctate or bubble-like lesions. EBMD has a significant impact on preoperative biometrics and intraocular lens power calculation, which can lead to inaccurate measurement and postoperative refractive accident, and cataract surgeons must be aware of this. This article reviews recent research and conference reports on the impact of EBMD on cataract surgery, as a reference for refractive cataract surgeons, thus improving the preoperative diagnosis and detection rate, so as to provide the optimal treatment plan for patients.

Comparison of corneal biomechanics in the early postoperative period between TransPRK and SMILE / 中华实验眼科杂志

Objective:To investigate the effects of transepithelial photorefractive keratectomy (TransPRK) and femtosecond small incision lenticule extraction (SMILE) on corneal biomechanics measured by the Ocular Response Analyzer in the early postoperative period.Methods:A cohort study was conducted.The right eyes of 56 patients who underwent TransPRK and 52 patients who underwent SMILE in Dalian Medical University Affiliated Dalian Third People's Hospital from November 2020 to June 2021 were continuously included.The postoperative follow-up was 3 months.The central corneal thickness (CCT) and keratometry (Km) were measured 1 month and 3 months after surgery.The corneal-compensated intraocular pressure (IOPcc), corneal resistance factor (CRF), corneal hysteresis (CH), and 19 repeatable mechanical infrared signal waveform parameters measured by the Ocular Response Analyzer were recorded before the surgery, 1 month and 3 months after the surgery, respectively.The measurement indexs at different time points between two groups were compared.This study adhered to the Declaration of Helsinki and the study protocol was approved by the Ethics Committee of Dalian Medical University Affiliated Dalian Third People's Hospital (No.2019-KT-010). Written informed consent was obtained from each patient before surgery.Results:There was no significant difference in CCT, Km, and IOPcc between the two groups at 1 month and 3 months after the surgery (all at P>0.05). In both groups, CRF, CH, p1area, p2area, p1area1, p2area1, w1, w2, w11, w21, h1, h2, h11, h21, dive1, dive2 and mslew1 were decreased, while path1, path2, path11, and aplhf were increased at 1 month after the surgery compared with before surgery, showing statistically significant differences (all at P<0.05). In both groups, CRF, CH, p1area, p2area, p1area1, p2area1, w1, w2, w11, w21, h1, h2, h11, h21, dive1 decreased, while path1, path2, path11, and aplhf were increased at 3 months after the surgery in comparison with before surgery, showing statistically significant differences (all at P<0.05). In SMILE group, the dive2 were decreased at 3 months after the surgery compared with before surgery, and the difference was statistically significant ( P<0.01). At 1 month after the surgery, p1area, p2area, p1area1, p2area1, w1, w2, w11, w21, dive1 and dive2 were higher, while CH, path1, path2, and path11 were smaller in TransPRK group than in SMILE group, showing statistically significant differences between them (all at P<0.05). At 3 months after the surgery, p1area, p2area, p1area1, p2area1, w1, w2, w11, w21, h2, h21, dive1 and dive2 were higher, while path1, path2, and path11 were smaller in TransPRK group than in SMILE group, showing statistically significant differences between them (all at P<0.05). Conclusions:Corneal biomechanics are weakened after both TransPRK and SMILE.In the early postoperative period, the mechanical infrared waveform parameters measured by the Ocular Response Analyzer are better after TransPRK than after SMILE.

Comparison of visual quality after refractive surgery between smart pulse technology-assisted transepithelial photorefractive keratectomy of 1 050Hz ablation frequency and small incision lenticule extraction / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To compare the visual quality between smart pulse technology-assisted(SPT)transepithelial photorefractive keratectomy(TransPRK)of 1 050Hz ablation frequency and small incision lenticule extraction(SMILE)for myopia and astigmatism.METHODS: A total of 138 cases(248 eyes)who received corneal refractive surgery in the Eye Hospital of Chengdu University of TCM were enrolled from July 2020 to January 2021. The patients were divided into TransPRK group(64 cases, 123 eyes)and SMILE group(74 cases, 125 eyes)according to the surgical method. The follow-up duration was 6mo. Strehl ratio(SR)and high-order aberration at 6mm pupil diameter measured by Sirius anterior segment integrated analyzer and LogMAR visual acuity were recorded at different preoperative and postoperative time points.RESULTS: The uncorrected visual acuity(UCVA)of TransPRK group was worse than SMILE group at 1wk and 1mo after surgery(all P<0.05), but UCVA was better in TransPRK group at 6mo after surgery(P<0.05). SR in TransPRK group was lower than that in SMILE group at 1wk and 1mo after surgery(all P<0.05). There was no significant difference in SR between the two groups at 3 and 6mo after surgery(P=0.968, 0.433). At 1wk after surgery, there was no significant difference in coma between the two groups(P=0.554). At 1, 3, and 6mo after surgery, coma in the TransPRK group was lower than that in SMILE group(all P<0.05). At 1wk, 1 and 3mo after surgery, the trefoil aberration in TransPRK group was higher than that in SMILE group(all P<0.05). At 6mo after surgery, there was no significant difference in trefoil aberration between the two groups(P=0.167). At 6mo after surgery, UCVA of TransPRK group and SMILE group were -0.13±0.05 and -0.11±0.08, respectively, which were better than the best corrected visual acuity(BCVA)before surgery(-0.07±0.05 and -0.07±0.05; all P<0.05). Furthermore, the SR of both groups was higher than that before surgery(all P<0.05).CONCLUSION: Both SPT-assisted TransPRK of 1 050Hz ablation frequency and SMILE can achieve better visual acuity after refractive surgery, while SMILE has better visual quality at 1wk and 1mo after surgery. However, SPT-assisted TransPRK of 1 050Hz ablation frequency has better visual acuity at 6mo after surgery than SMILE, and the coma is smaller.

Visual quality observation of transepithelial photorefractive keratectomy and femtosecond small incision lenticule extraction for the correction of low myopia / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To observe the changes in corneal aberrations and the characteristics of visual quality after transepithelial photorefractive keratectomy(T-PRK)and femtosecond small incision lenticule extraction(SMILE)in the correction of low myopia.METHODS: Prospective cohort study. A total of 32 cases(32 eyes)with low myopia who underwent T-PRK surgery and 45 cases(45 eyes)of SMILE surgery at Weifang Eye Hospital from April 2021 to April 2022 were selected. The uncorrected visual acuity(UCVA), best corrected visual acuity(BCVA), spherical equivalent(SE), corneal higher-order aberrations(HOAs)and objective visual quality were compared between the two groups.RESULTS:All patients completed the surgery successfully without complications such as infection. At 3mo postoperatively, the safety index was 1.13±0.16 and 1.16±0.17(P=0.48)and the efficacy index was 1.10±0.20 and 1.15±0.18(P=0.27)in the T-PRK and SMILE groups, respectively. The percentage of UCVA(LogMAR)≤0 in the T-PRK and SMILE groups was 94% and 98%, respectively. The percentage of the residual SE within ±0.5D was 88% and 87% in the two groups, respectively. The HOAs and spherical aberration in both groups were significantly increased(P≤0.01), and the increase was not statistically significant between the two groups(P=0.31, 0.89). There was no significant change in horizontal coma, horizontal trefoil and vertical trefoil in both groups(P&#x0026;#x003E;0.05). The vertical coma in SMILE group was significantly increased(P&#x0026;#x003C;0.001), while there was no significant change in T-PRK group(P&#x0026;#x003E;0.05), and the increase was significantly greater in SMILE group than in T-PRK group(P&#x0026;#x003C;0.001). There was no significant difference in objective scattering index(OSI), modulation transfer function cut off frequency(MTFcut off), Strehl ratio(SR), visual acuity(VA)100%, VA20% and VA9% between the two groups(P&#x0026;#x003E;0.05).CONCLUSION:Both T-PRK and SMILE showed good safety, efficacy, and visual quality in correcting low myopia, while SMILE induced more vertical coma than T-PRK.

Clinical analysis of functional optical zone after transepithelial photorefractive keratectomy in patients with different degrees of myopic astigmatism / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To evaluate the effect of preoperative degrees of myopic astigmatism and anterior corneal curvature on the functional optical zone(FOZ)after transepithelial photorefractive keratectomy(TransPRK).METHODS: Retrospective study was conducted on 78 patients(130 eyes)with myopia and myopic astigmatism who underwent TransPRK, and they were divided into control group(cylinder 0D), moderate astigmatism group(-0.50～-2.00D)and high astigmatism group(&#x003E;-2.00～&#x003C;-6.00D). The FOZ was measured and compared among the three groups 6mo after operation. The correlations between attempted correction, anterior corneal curvature, corneal aberrations, Q value, and the FOZ were analyzed.RESULTS: At 6mo after operation, the mean FOZ was 5.16±0.12mm in the control group, 5.29±0.23mm in the moderate astigmatism group, and 5.49±0.23mm in the high astigmatism group(P&#x003C;0.001), and the FOZ of the high astigmatism group was significantly higher than moderate astigmatism and control group(P&#x003C;0.05, P&#x003C;0.001); Pearson correlation analysis showed that the changes in spherical equivalent, total corneal higher-order aberrations(HOAs), coma, and spherical aberration were all negatively correlated with FOZ(all P&#x003C;0.05); and FOZ positively correlated with changes in the steep curvature(K2), mean curvature(Km), corneal astigmatism, and Q value(all P&#x003C;0.01). Multiple linear regression analysis showed that there was still positive correlation between preoperative K2 and FOZ after adjusting for other risk factors(P&#x003C;0.001).CONCLUSION: Patients with high astigmatism can obtain a larger FOZ and less induced coma after TransPRK. A larger FOZ can be achieved in eyes with steeper keratometry.

Aumento das aberrações de alta ordem pós-ceratectomia fotorrefrativa guiada por frente de onda: relato de caso / Increased high-order aberrations after wavefront-guided photorefractive keratectomy: case report

RESUMO Ao remodelar a córnea usando um perfil de ablação individualizado para cada olho obtido por meio de aberrometria de frente de onda, o tratamento guiado por frente de onda tenta reduzir aberrações preexistentes e induzidas cirurgicamente, minimizando as aberrações de alta ordem (HOAs) visualmente significativas. No entanto, o aumento de HOA ainda é uma preocupação, mesmo com ablações personalizadas. Na cirurgia refrativa a laser miópica, como o feixe de laser entra na periferia, algumas partes são refletidas, e o feixe circular se torna elíptico, resultando em diminuição na eficácia da energia do laser. A subablação da córnea periférica pode ser induzida por esses fatores que aumentam a HOA, especialmente a aberração esférica. Este relato tem por finalidade mostrar uma paciente alto míope submetida à PRK guiada por frente de onda que evoluiu com aumento das HOAs.

ABSTRACT By reshaping the cornea using an individualized ablation profile for each eye obtained through wavefront aberrometry, wavefront guided treatment attempts to reduce preexisting and surgically induced aberrations while minimizing visually significant higher-order aberrations (HOAs). However, HOA enhancement is still a concern, even with custom ablations. In the myopic laser refractive surgery, as the laser beam enters the periphery, some parts are reflected, and the circular beam becomes elliptical, resulting in a decrease in the effectiveness of the laser energy. Peripheral corneal subablation can be induced by these factors that increase HOA, especially spherical aberration. This report aims to show a high myopic patient undergoing wavefront-guided PRK, who evolved with an increase in HOAs.

Avaliação do conhecimento sobre cirurgia refrativa por meio de questionário eletrônico / Evaluation of knowledge in refractive surgery using an on-line questionnaire

RESUMO Objetivo: Desenvolver e aplicar um questionário eletrônico para avaliação do conhecimento em cirurgia refrativa na população analisada. Métodos: Foi aplicado um questionário eletrônico a uma população composta de 840 participantes voluntários maiores de 18 anos. Resultados: A média da idade dos participantes foi 37,85 anos, sendo 60,1% do feminino. Dentre os participantes, 20,95% reportaram ter sido submetidos a alguma cirurgia ocular prévia, sendo 73,86% com objetivo refrativo. Entre estes, 73,08% mostraram-se satisfeitos/muito satisfeitos com o resultado. O critério mais importante na escolha de um cirurgião refrativo foi a indicação por um conhecido que realizara a cirurgia (43,81%). Destaca-se que os participantes submetidos à cirurgia refrativa discordaram que "a cirurgia é um procedimento simples e isento de riscos" mais do que as demais pessoas (p=0,0045) e também que "o objetivo principal da cirurgia é 'zerar' o grau" (p=0,0252). Conclusão: Nota-se a necessidade de melhorar o conhecimento pré-operatório da população sobre cirurgia refrativa e também de educação continuada para os oftalmologistas. Este estudo fomenta o desenvolvimento de novas ferramentas de educação com informações claras e de fácil acesso, que tenham caráter informativo, e não de convencimento.

ABSTRACT Objective: The purpose of this study was to develop and apply an online questionnaire to assess knowledge in Refractive Surgery in the analyzed population. Methods: An online questionnaire was applied to a population composed of 840 volunteer participants over 18 years of age. Results: The mean age of population was 37.85 years, of whom 60.1% were female. 20.95% of the participants reported having undergone previous eye surgery, 73.86% of which had a refractive objective. Among these, 73.08% were satisfied / very satisfied with the result. The most important criterion when choosing a refractive surgeon was the indication by a friend who underwent the procedure (43.81%). It is noteworthy that the participants who underwent refractive surgery disagreed more than the other people that "the surgery is a simple and risk-free procedure" (p = 0.0045) and that "the main objective of the surgery is to "zero" the diopter" (p = 0.0252). Conclusion: It is essential to improve population's preoperative knowledge about Refractive Surgery, as well as continuing education for ophthalmologists. Therefore, this study encourages the development of new education tools with clear and easily accessible information, which should be informative, and not convincing.

Transepithelial phototherapeutic keratectomy for post-traumatic recurrent corneal erosions

Purpose: To evaluate the outcomes of transepithelial phototherapeutic keratectomy (transepithelial PTK) for treatment of posttraumatic recurrent corneal erosions. Methods: Twenty?four eyes of 22 patients with posttraumatic recurrent corneal erosions who were treated with transepithelial PTK from April 2018 to July 2020 were included in this retrospective study. The rates of recurrent erosions and complications were evaluated during the follow?up after surgery. Visual acuity and refraction were recorded preoperatively and 1 year after surgery. Total corneal astigmatism, total corneal irregular astigmatism, and total corneal spherical aberrations were recorded using corneal tomography preoperatively and 1 year after surgery. Results: Mean postoperative follow?up was 13 months (range: 12� months). None of the patients suffered from any complications or further erosions. Uncorrected distance visual acuity, best?corrected distance visual acuity, spherical equivalent, and cylinder remained stable at 1?year postoperatively compared with the baseline (P = 0.214, P = 0.461, P = 0.084, and P = 0.879, respectively). Moreover, there was no significant difference in total corneal astigmatism, total corneal irregular astigmatism, and total corneal spherical aberrations between baseline and 1?year postoperative visit (P = 0.938, P = 0.136, and P = 0.981, respectively). Conclusion: Transepithelial PTK was an effective treatment for patients with posttraumatic recurrent corneal erosions.