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

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.

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.

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.

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.

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.

Resultados refractivos y visuales en cirugía fotoablativa en pacientes miopes / Refractive and visual results in photoablative surgery in myope patients

Objetivo: Evaluar los resultados refractivos y visuales post cirugía refractiva corneal con láser de excímero (LASEK-MMC o PRK-MMC) en pacientes miopes con o sin astigmatismo asociado. Método: Se realizó un estudio preexperimental del tipo antes y después, en el que fueron incluidos 81 pacientes (162 ojos) tratados con LASEK-MMC (65 pacientes) o PRK-MMC (16 pacientes) seguidos por tres meses. Se les realizó un examen oftalmológico completo y se evaluaron las variables: edad, sexo, diagnóstico y tipo de miopía, así como agudeza visual, esfera, cilindro, equivalente esférico precirugía y poscirugía. Además, se analizó la función visual y los resultados de la refracción. Resultados: El valor de la mediana de edad fue de 24,0 años en los pacientes tratados con LASEK-MMC y en el grupo con PRK-MMC fue de 23,0 años. En ambos grupos existió un predominio del sexo femenino. La totalidad de los pacientes tratados presentaba un astigmatismo miópico compuesto con niveles de miopía leve. A los tres meses el 96,9 por ciento de los pacientes tratados con LASEK-MMC y el 93,8 por ciento de los tratados con PRK-MMC tenían una agudeza visual no corregida de 20/20 o más y todos tenían una visión de 20/40 o más. Conclusiones: La cirugía fotoablativa con láser tiene buenos resultados refractivos y visuales ya que la mayoría de los pacientes quedaron emétropes con una marcada mejoría de la agudeza visual sin corrección y de la refracción en el posoperatorio(AU)

Objective: To evaluate refractive and visual outcomes after excimer laser corneal refractive surgery (laser-assisted subepithelial keratectomy [LASEK] or photorefractive keratectomy [PRK], with intraoperative application of mitomycin-C [MMC]) in myopic patients with or without associated astigmatism. Methods: A preexperimental, before-and-after study was carried out with 81 patients (162 eyes) treated with LASEK-MMC (65 patients) or PRK-MMC (16 patients) and followed for three months. A complete ophthalmologic examination was done and the following variables age, sex, diagnosis and type of myopia were assessed, as well as pre-surgery and post-surgery visual acuity, sphere, cylinder and spherical equivalent. In addition, visual function and the refraction results were analyzed. Results: The median age was 24.0 years in the LASEK-MMC group and 23.0 years in the PRK-MMC group. In both groups there was a predominance of the female sex. All treated patients had compound myopic astigmatism with mild myopia. At three months, 96.9 percent of patients treated with LASEK-MMC and 93.8 percent of patients treated with PRK-MMC had uncorrected visual acuity of 20/20 or better, and all had vision of 20/40 or better. Conclusions: Laser photoablative surgery has good refractive and visual outcomes as most patients became emmetropic with marked improvement in uncorrected visual acuity and refraction postoperatively(AU)

Visual outcomes and quality of life before and after photorefractive keratectomy

Purpose: To compare visual outcomes and vision?related quality of life (VRQoL) between subjects before and after photorefractive keratotomy (PRK) and controls. In addition, VRQoL was compared between subjects at different periods of PRK surgery. Methods: This was a cross?sectional study that included subjects with refractive errors aged 19–40 years and age?matched controls. Subjects were divided into three groups: pre?, post?PRK, and control. Subjects in the post?PRK group were divided into three subgroups (1?week, <6?month, and >6?month follow?up visits). Measurements including uncorrected distance visual acuity (UCVA), corrected distance visual acuity (CDVA), spherical equivalent (SE) of manifest refraction, and corneal topography were obtained for all participants. The Quality of Life Impact of Refractive Correction (QIRC) questionnaire was administered to compare VRQOL between groups and between post?refractive surgery subgroups. Results: A total of 145 participants were included in this study. The mean age ± standard deviation (SD) of all participants was 26.29 ± 5.1 years. There was a significant difference (P < 0.001) in total QIRC scores between groups. The total QIRC score was better in the post?PRK group than in the pre?PRK and control groups. The scores of items included in the convenience, well?being, and health concern domains were significantly higher in the post?PRK group than in the pre?PRK and control groups. Within the post?PRK group, significant differences (P < 0.001) were found in UCVA and SE between the post?PRK subgroups. Uncorrected VA and SE were better in the post?PRK groups who were followed up in the < 6 and > 6 months subgroups than in the 1?week follow?up subgroup (P < 0.0001). Conclusion: A significant improvement in visual outcomes and VRQoL occurred after PRK surgery. Subjects enjoyed their VRQoL after refractive surgery.

Effects of Rapamycin on corneal haze after photorefractive keratectomy in rabbits / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To investigate the effect of modulated autophagy activity on subepithelial haze after photorefractive keratectomy(PRK)in rabbits.<p>METHODS: Totally 64 New Zealand white rabbits were randomly divided into 4 groups according to different postoperative medication after PRK operation, including simple PRK group, 14μmol/L DMSO group, 50μmol/L rapamycin group and 100μmol/L rapamycin group. According to the group situation, two hours after the operation, eye drops were given, 3 times a day for 7d. Another 16 rabbits were selected as normal control group. The postoperative inflammatory response and corneal epithelial healing were observed with slit-lamp microscope every day. Haze formation of each group at 1 and 4wk after PRK was collected by slit-lamp microscopy system. Eight rabbits in each group were killed by air embolization 1 and 4wk after PRK, and corneal tissue was extracted and frozen for later use. Immunohistochemistry was used to detect the expression levels of transforming growth factor-β1(TGF-β1), α-smooth muscle actin(α-SMA), and matrix metalloproteinase-2(MMP-2). Real-time PCR was used to detect the relative expression levels of autophage-5(ATG5), autophage-12(ATG12), B lymphocytoma gene-2(Bcl-2)and cysteine aspartic proteinase-3(Caspase3)genes.<p>RESULTS: Corneal epithelium of all operative rabbits healed completely at 3-4d and no significant difference in healing time between the groups after operation(<i>F</i>=0.745, <i>P</i>=0.530). During the observation period, haze was the most obvious at 4wk after operation in all groups. The haze symptoms were more serious in the simple operation group and the 14μmol/L DMSO group, followed by the 50μmol/L rapamycin group. The haze symptoms in the 100μmol/L rapamycin group were significantly relieved than those in other groups. There was no significant difference in the haze grading with different time points after operation among all groups(all <i>P</i><0.05). Immunohistochemistry showed that the expression of TGF-β1, MMP-2 and α-SMA was stronger in the operation group and 14μmol/L DMSO group, followed by 50μmol/L rapamycin group, and weakest in 100μmol/L rapamycin group than other groups at 1 and 4wk after operation(all <i>P</i><0.05). The results of PCR showed that the relative expression of ATG5, ATG12 and Bcl-2 mRNA in 50μmol/L rapamycin group and 100μmol/L rapamycin group were significantly higher than those in simple operation group and 14μmol/L DMSO group at 1 and 4wk after operation(all <i>P</i><0.05); The relative expression of Caspase3 mRNA in 50μmol/L rapamycin group and 100μmol/L rapamycin group was significantly lower than that in simple operation group and 14μmol/L DMSO group(all <i>P</i><0.05).<p>CONCLUSION: Rapamycin can enhance autophagy level and inhibit apoptosis level, thus reducing haze formation after PRK in rabbits.

Effect of Trans-PRK combined with 0.02% MMC on corneal density in patients with moderate myopia / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To evaluate the effect of 0.02% mitomycin-C(MMC)on the corneal density after transepithelial photorefractive keratectomy(Trans-PRK). METHODS: Retrospective case analysis. Selected 28 patients with 56 eyes in moderate myopia who underwent Trans-PRK surgery from January 2021 to June 2021 in our hospital. They were divided into MMC group in 28 eyes with a combination of 0.02% MMC 20s during the surgery and the control group in 28 eyes was not use MMC during the surgery. The Pentacam anterior segment analyzer was used to measured the corneal density in different diameter ranges and different thickness layers before and after surgery at 14d, and after surgery at 1 and 3mo.RESULTS: The total corneal density value of MMC group was 16.60(15.70,17.10 )before the surgery, after the surgery at 14d was 16.63(15.90,17.50 ), at 1mo was 16.57(15.10,16.70 ), at 3mo was 16.04(14.60,16.60 ). The total corneal density value of control group was 16.30(15.50,17.30 )before the surgery, after the surgery at 14d was 16.20(15.20,17.10 ), at 1mo was 16.08(14.90,16.40 )and at 3mo was 15.60(14.60,16.40 ). In the zone of 0-2mm diameter was centered on the corneal vertex, the corneal density of the two groups at 14d after the surgery was higher than those before surgery(P<0.001 ). In the zone of 2-6mm diameter, the corneal density of the two groups at 1mo and 3mo after surgery was higher than those before the surgery(P<0.001). In the zone of 6-10mm, the corneal density of the two groups at 14d, 1 and 3mo after surgery was higher than those before the surgery(P<0.001). In the layer of anterior 120 μm, the corneal density of the two groups at 1mo and 3mo after the surgery was decreased than that before surgery(P<0.01). In the middle layer, the corneal density of the two groups at 1mo after the surgery was decreased than those before surgery(P<0.01).CONCLUSION:The use of 0.02% MMC during the operation can reduce the corneal density and increase the corneal light transmittance in the early postoperative period. The occurrence and prognosis of haze can be effectively quantified by observing the changes of corneal optical density in different ranges in different time periods after operation.

Observation and study on uncorrected distance visual acuity and ocular adjustment function before and after excimer laser photorefractive keratectomy / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To analyze the changes of uncorrected distance visual acuity(UCDVA)and ocular accommodation before and after excimer laser photorefractive keratectomy(PRK).METHODS: A retrospective study. There were 120 patients(240 eyes)who underwent PRK surgery in our center from December 2017 to December 2019 divided into two groups according to the diopter of spherical equivalent(SE): 70 cases with SE≤-6.00D in the mild to moderate myopia group and 50 cases with -6.00D&#x003C;SE≤-9.00D in the high myopia group which were observed and analyzed. The UCDVA(LogMAR), monocular accommodative amplitude(AMP), negative relative accommodation(NRA), positive relative accommodation(PRA)and monocular accommodative flipper(AF)were measured before and after operation at 1wk, 1 and 3mo. RESULTS: In the group of low-moderate myopia and high-myopia group, the UCDVA at 1wk, 1 and 3 mo after operation was significantly increased compared with those before operation(all P&#x003C;0.01). The increase of UCDVA of low to moderate myopia group was better than that in the high myopia group at 3mo after operation(P&#x003C;0.05). Monocular AMP in the both groups firstly decreased and increased afterwards, and there was a significant decrease than that before operation at 1wk and 1mo after operation(P&#x003C;0.01). AMP reached and was better than that before operation at 3mo after operation(P&#x003C;0.01). The increase of low to moderate myopia group was both higher and faster than that of high myopia group. Compared with PRA before operation, the patients of low to moderate myopia group decreased at 1wk after operation(P&#x003C;0.01), postoperative levels at 1mo recovered to preoperative level(P&#x003E;0.05)and postoperative at 3mo was superior to preoperative operation(P&#x003C;0.05); High myopia group did not change significantly at 1wk and 1mo after operation compared with preoperative operation(P&#x003E;0.05), and increased at 3mo after operation compared with preoperative level(P&#x003C;0.01). For low to moderate myopia group, there was no significant difference in preoperative and postoperative NRA, and at 1wk after operation, NRA of high myopia group temporarily increased compared with preoperative operation(P&#x003C;0.01). At 1mo after operation, it returned to the preoperative level(P&#x003E;0.05), and significantly increased at 3mo after operation compared with preoperative operation(P&#x003C;0.01). Monocular AF for both groups significantly decreased at 1wk after operation compared with preoperative operation, recovered at 1mo after operation and was significantly better at 3mo after operation(all P&#x003C;0.01); The low-to-moderate group increased more than the high-myopia group.CONCLUSION: PRK has a good correction effect for myopia below -9.00D, and people in low to moderate myopia have a better postoperative UCDVA correction effect than those in high myopia. The eye accommodation will be abnormal in a short period after operation. The recovery and improvement time of accommodative function in low-moderate myopia group are shorter than that in high myopia group, but both groups can recover and improve at 3mo after operation compared with the preoperative levels.

Diferentes concentraciones de mitomicina C en la prevención del haze en la queratectomía fotorrefractiva / Different concentrations of mitomycin C for haze prevention in photorefractive keratectomy

Objetivo: Evaluar la utilidad de dos concentraciones de mitomicina C para la prevención del haze en la queratectomía fotorrefractiva. Métodos: Se realizó un estudio experimental aleatorizado en 26 ojos de 17 pacientes con defectos miópicos. Los pacientes fueron asignados a dos grupos según las dosis de mitomicina C (0,02 por ciento grupo 1 y 0,002 por ciento grupo 2). La variable de respuesta principal fue la presencia de haze. Se buscó correlación entre la magnitud del haze con grado de ametropía tratada, profundidad de ablación, microscopia endotelial y resultados visuales y refractivos. Resultados: A los 6 meses la mayoría de los pacientes del grupo 1 no presentó haze (ocho ojos / 57 por ciento), y del grupo 2 mantuvieron haze 0,5 (6 ojos / 50 por ciento). En la ametropía severa el haze en el grupo 2 fue mayor que en el grupo 1 durante todo el posoperatorio, y se observó la mayor diferencia al sexto mes con 0,5 ± 0,4 vs. 1,5 ± 0,32. En ablaciones > 75 micras el grupo dos terminó con más haze que el uno, con 0,5 ± 0,44 vs. 1,75 ± 0,76. La agudeza visual sin corrección se vio más afectada en el grupo 2. No hubo daño endotelial en ningún grupo. Conclusión: La presencia de haze predomina en los casos tratados con dosis 0,002 por ciento de mitomicina C, comparada con la dosis 0,02 por ciento, aunque en este caso ambos grupos mantuvieron un resultado visual y refractivo adecuado y baja toxicidad endotelial.

Objective: Evaluate the usefulness of two concentrations of mitomycin C for haze prevention in photorefractive keratectomy. Methods: An experimental randomized study was conducted of 26 eyes of 17 patients with myopic defects. The patients were divided into two groups according to their mitomycin C doses (Group 1: 0.02 percent and Group 2: 0.002 percent). The main response variable was the presence of haze. Verification was performed of the correlation between haze magnitude and the degree of the ametropia treated, ablation depth, endothelial microscopy, and visual and refractive results. Results: At six months most patients in Group 1 did not have any haze (eight eyes / 57 percent), whereas 0.5 (6 eyes / 50 percent) in Group 2 still had haze. In severe ametropia, haze was larger in Group 2 than in Group 1 throughout the postoperative period, the greatest difference being observed in the sixth month with 0.5 ± 0.4 vs 1.5 ± 0.32. In ablations > 75 microns, Group 2 ended with more haze than Group 1, with 0.5 ± 0.44 vs 1.75 ± 0.76. Uncorrected visual acuity was more affected in Group 2. No endothelial damage occurred in either group. Conclusion: The presence of haze prevails in cases treated with 0.002 percent doses of mitomycin C, as compared with 0.02 percent doses, though in this case both groups maintained an appropriate visual and refractive result and low endothelial toxicity(AU)

Treatment strategy for bilateral severe subepithelial fibrosis after photorefractive keratectomy enhancement / Estratégia de tratamento para fibrose subepitelial grave bilateral após aprimoramento com ceratectomia fotorrefrativa

ABSTRACT A 27-year-old healthy man with a history of bilateral photorefractive keratectomy (PRK) enhancement after femtosecond laser in situ keratomileusis (LASIK) presented with decreased uncorrected distance visual acuity (UDVA) of 20/125 in the right eye (OD) and 20/300 in the left eye (OS) six months after PRK. Examination revealed bilateral dense subepithelial opacities. Both eyes (OU) were treated with superficial keratectomy combined with phototherapeutic keratectomy (PTK) and adjunctive application of mitomycin C 0.02%. At three months follow up UDVA was 20/30 OD and 20/25 OS. Superficial keratectomy combined with PTK seems to be a safe and efficient technique for treatment of dense subepithelial scar formation following PRK enhancement after LASIK.

RESUMO Um homem saudável de 27 anos de idade com história de aprimoramento com ceratectomia fotorrefrativa (PRK) bilateral, após Ceratomileuse Assistida por Excimer Laser In Situ (LASIK) com laser de femtossegundos, apresentou diminuição da acuidade visual à distância não corrigida (AVNC) de 20/125 no olho direito (OD) e 20/300 no olho esquerdo (OE) seis meses após PRK. O exame revelou opacidades subepiteliais densas bilaterais. Ambos os olhos (AO) foram tratados com queratectomia superficial combinada com ceratectomia fototerapêutica (PTK) e aplicação adjuvante de mitomicina C a 0,02%. Aos três meses de acompanhamento, o AVNC foi de 20/30 OD e 20/25 OE. A ceratectomia superficial combinada com PTK parece ser uma técnica segura e eficiente para o tratamento da formação densa de cicatrizes subepiteliais após o aprimoramento com PRK pós-LASIK.