Advances in peripheral defocus and myopia prevention and control / 国际眼科杂志(Guoji Yanke Zazhi)

The global prevalence of myopia is increasing year by year, leading to many ocular health issues and social problems. In recent years, it has been confirmed that peripheral defocus is closely related to the occurrence and development of myopia. Alteration of the state of peripheral defocus can significantly influence the progression of myopia and emmetropization, but the exact mechanisms are still unclear. At present, there is no method that can completely control myopia. Nowadays, the main controlling methods, including orthokeratology lens, peripheral defocus lens and multi-focal soft lens, have been confirmed to be closely related to peripheral defocus. In this paper, we will review and summarize the development and effect of these peripheral defocus relating control methods. In addition, the researches on the related mechanisms of peripheral retinal defocus and myopia prevention and control at home and abroad are reviewed, as well as the potential mechanisms of peripheral defocus, with a view to further improving the controlling effects of existing methods, developing new prevention and control methods and reducing the incidence and progression of myopia.

Advances in the effect of ocular hypertension on ocular refraction / 国际眼科杂志(Guoji Yanke Zazhi)

Ocular hypertension(OH)can cause a variety of ocular structural and functional damage, among which the effect on ocular refraction has long been recognized in the clinic. The effect of OH on ocular refraction is related to the transparency and shape of refractive media, as well as the changes of the axial length. Due to the different speed and degree of intraocular pressure(IOP)elevation, the changes of refraction are reversible or irreversible. Irreversible changes in refraction are often accompanied by visual transmission impairment, and have a certain reference value for the evaluation of the latter condition. IOP changes lead to changes in the axial length, which are related to scleral remodeling and choroidal perfusion changes, and have a certain impact on the development of myopia and refractive error after cataract surgery. In this paper, the research progress of the changes of refractive media and axial length caused by OH, as well as the characteristics of the effects on ocular refraction are summarized, hoping to deepen the understanding of the effect of OH on ocular refraction, and provide reference for preventing irreversible ocular refractive changes, guiding the assessment of visual transmission damage and preventing or controlling the development of axial myopia.

Brazilian guideline for pediatric cycloplegia and mydriasis / Diretrizes brasileiras para cicloplegia e midríase em crianças

ABSTRACT Cycloplegia is crucial for reliable pediatric ophthalmology examinations. This document provides a re­commendation for pediatric cycloplegia and mydriasis for Brazilian ophthalmologists. This article was developed based on literature reviews; the clinical experience of Brazilian specialists, as obtained through questionnaires; and the consensus of the Expert Committee of the Brazilian Pediatric Ophthalmology Society. According to the best evidence and formulations available in Brazil, this committee recommends the use of one drop of 1% cyclopentolate plus one drop of 1% tropicamide in children older than 6 months and two drops of 1% tropicamide 0-5 minutes apart for those younger than 6 months. Mydriasis may be increased by a single drop of 2.5% phenylephrine. For retinopathy of prematurity screening, the recommendation is 0.5% or 1% tropicamide, administered two or three times, 5 minutes apart, and 2.5% phenylephrine, used preferably once. In all scenarios, we recommend the use of a prior drop of 0.5% proxymetacaine.

RESUMO A cicloplegia é crucial para um exame oftalmológico pediátrico acurado. Este documento visa a fornecer uma recomendação para cicloplegia e midríase pediátrica para oftalmologistas brasileiros. Foi desenvolvido com base em revisão literária, na experiência clínica de especialistas brasileiros, por meio de questionários, e no consenso do comitê de especialistas da Sociedade Brasileira de Oftalmologia Pediátrica (SBOP). De acordo com as melhores evidências, este comitê recomenda o uso de uma gota de ciclopentolato 1%, mais uma gota de tropicamida 1% em crianças maiores de 6 meses e duas gotas de tropicamida 1% com intervalo de 0-5 minutos para menores de 6 meses. A midríase pode ser potencializada por uma gota de fenilefrina 2,5%. Para o rastreamento da retinopatia da prematuridade, a recomendação é tropicamida 0,5 ou 1%, duas ou três vezes, com 5 minutos de intervalo, e 2,5% de fenilefrina, preferencialmente uma vez. O uso prévio de proxymetacaína 0,5% é sempre recomendado.

Prediction of spherical equivalent refraction and axial length in children based on machine learning

Purpose: Recently, the proportion of patients with high myopia has shown a continuous growing trend, more toward the younger age groups. This study aimed to predict the changes in spherical equivalent refraction (SER) and axial length (AL) in children using machine learning methods. Methods: This study is a retrospective study. The cooperative ophthalmology hospital of this study collected data on 179 sets of childhood myopia examinations. The data collected included AL and SER from grades 1 to 6. This study used the six machine learning models to predict AL and SER based on the data. Six evaluation indicators were used to evaluate the prediction results of the models. Results: For predicting SER in grade 6, grade 5, grade 4, grade 3, and grade 2, the best results were obtained through the multilayer perceptron (MLP) algorithm, MLP algorithm, orthogonal matching pursuit (OMP) algorithm, OMP algorithm, and OMP algorithm, respectively. The R2 of the five models were 0.8997, 0.7839, 0.7177, 0.5118, and 0.1758, respectively. For predicting AL in grade 6, grade 5, grade 4, grade 3, and grade 2, the best results were obtained through the Extra Tree (ET) algorithm, MLP algorithm, kernel ridge (KR) algorithm, KR algorithm, and MLP algorithm, respectively. The R2 of the five models were 0.7546, 0.5456, 0.8755, 0.9072, and 0.8534, respectively. Conclusion: Therefore, in predicting SER, the OMP model performed better than the other models in most experiments. In predicting AL, the KR and MLP models were better than the other models in most experiments.

Non-compliance for wearing spectacles: Prevalence and determinants in school-going children in South India

Purpose: To study the prevalence and determinants of compliance with spectacle wear among school?age children in South India who were given spectacles free of charge under a school vision screening program. Methods: A cross?sectional, descriptive study was performed. The participants were recruited from the school from Tirunelveli and Tuticorin districts of Tamil Nadu, where a school vision screening camp was conducted between January 2012 and October 2012. The school screening was performed under “Lavelle Pediatric Eye Care Project”. Of the 129,720 children examined of 249 schools, 4253 of children had refractive error and 3333 were prescribed and dispensed spectacles. A total of 683 children were interviewed, who were not wearing glasses on follow?up. Results: About 20% of the participants (683/3333) were not wearing their spectacles at examination. The most common reasons given for non?wear were lost (44.9%) or broken (35.3%) spectacles. There was no gender preference on compliance to spectacles. Conclusion: Compliance with spectacle wear is less even when spectacles are provided free of cost, particularly in children among the age group of 5–15 years. Because factors such as type of school, area (urban or rural), parent’s income, occupation, and their education were not significantly affecting the compliance of spectacle wear, proper encouragement and counseling of the parents and the child become extremely important.

Effects of a new-generation hybrid contact lens on visual performance and vision-related quality of life in patients with keratoconus / Os efeitos de uma lente de contato híbrida de nova geração no desempenho visual e na qualidade de vida relacionada à visão em pacientes com ceratocone

ABSTRACT Purpose: The aim of this study was to evaluate the efficacy of a new-generation hybrid contact lens for improving visual outcomes and vision-related quality-of-life performance in patients with keratoconus who had intolerance or treatment failure of conventional correction methods such as the use of soft silicone-hydrogel or rigid gas-permeable contact lenses. Methods: Twenty-eight patients with keratoconus (42 eyes) were enrolled in this prospective cross-sectional study. Airflex (Swisslens) lenses were fitted in the patients' eyes in accordance with the manufacturer's instruction. Ophthalmologic examinations, including manifest refraction, best-corrected distance visual acuity, slit-lamp biomicroscopy, and National Eye Institute Visual Function Questionnaire 25 (NEI-VFQ-25) assessment, were performed at baseline and the 6-month visit. Results: An adequate fit was achieved in 39 eyes (92.9%) of 26 patients. Six eyes of 3 patients were excluded from the study owing to discontinuation of lens wearing. The mean age of the successful wearers was 20.3 ± 4.9 years. The mean best-corrected distance visual acuity was statistically significantly improved from 0.62 ± 0.30 to 0.11 ± 0.06 logMAR with the Airflex hybrid contact lenses (p<0.001). The mean overall composite NEI-VFQ-25 score statistically significantly increased with the Airflex hybrid contact lenses at the 6-month visit as compared with that at baseline (from 77.1 ± 16.3 to 90.9 ± 7.3, p=0.036). Statistically significantly better scores were obtained with the Airflex hybrid contact lenses in all the NEI-VFQ-25 subscale items (all p<0.05). No significant adverse effects were observed. Conclusions: New-generation hybrid contact lenses can be used as an effective alternative for correction of irregular astigmatism in patients with keratoconus who have intolerance or treatment failure of conventional methods. Significant improvement in vision-related quality-of-life in patients with keratoconus can be achieved with these lenses.

RESUMO Objetivo: Este estudo tem como objetivo avaliar a eficácia de lentes de contato híbridas de nova geração nos resultados visuais e na qualidade de vida relacionada à visão em pacientes com ceratocone com intolerância ou insucesso dos métodos de correção habituais, tais como lentes flexíveis de silicone-hidrogel ou rígidas permeáveis a gases. Métodos: Foram incluídos neste estudo transversal prospectivo 42 olhos de 28 pacientes com ceratocone. Uma lente Airflex (Swisslens) foi aplicada nos olhos de acordo com as instruções do fabricante. Um exame oftalmológico, incluindo refração manifesta, melhor acuidade visual corrigida para longe, biomicroscopia com lâmpada de fenda e a aplicação do National Eye Institute Visual Function Questionnaire-25 (NEI-VFQ-25), foi realizado no início do estudo e na visita de 6 meses. Resultados: Foi possível obter um ajuste adequado em 39 olhos (92,9%) de 26 pacientes. Foram excluídos do estudo 6 olhos de 3 pacientes devido à cessação do uso de lentes. A idade média dos usuários bem-sucedidos era de 20,3 ± 4,9 anos. A média da melhor acuidade visual corrigida para longe foi melhorada estatisticamente de 0,62 ± 0,30 para 0,11 ± 0,06 logMAR com as lentes de contato híbridas Airflex (p<0,001). A pontuação média geral composta no questionário NEI-VFQ-25 aumentou de forma estatisticamente significativa com a lente de contato híbrida Airflex na visita de 6 meses, em comparação com a pontuação inicial (de 77,1 ± 16,3 para 90,9 ± 7,3, p=0,036). As lentes de contato híbridas Airflex apresentaram pontuações melhores com significância estatística em todos os itens das sub-escalas do NEI-VFQ-25 (todos com p<0,05). Nenhum efeito adverso significativo foi observado. Conclusões: Lentes de contato híbridas de nova ge ração podem ser usadas como uma alternativa eficaz para a correção do astigmatismo irregular em pacientes com ceratocone com intolerância ou insucesso dos métodos habituais. Com essas lentes, pode-se alcançar uma melhora significativa na qualidade de vida relacionada à visão em pacientes com ceratocone.

Changes in retinal peripheral refractive status and aberrations before and after femtosecond laser-assisted laser in situ keratomileusis and small incision lenticule extraction / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To observe and compare the changes in retinal peripheral refraction and aberrations after femtosecond laser-assisted laser in situ keratomileusis(FS-LASIK)versus small incision lenticule extraction(SMILE)for myopia correction.METHODS: A total of 71 patients(71 eyes)with myopia who underwent FS-LASIK from October 2022 to April 2023 in our hospital were selected as the FS-LASIK group, and 80 patients(80 eyes)with myopia who underwent SMILE were selected as the SMILE group. All patients underwent corneal wavefront aberration measurement and multispectral refractive topography preoperatively and 3mo postoperatively, as well as refraction difference value(RDV)in the range of 0°～10°, 10°～20°, 20°～30°, 30°～40°, and 40°～53° in the annulus of the retina, which were recorded as RDV-(0°～10°), RDV-(10°～20°), RDV-(20°～30°), RDV-(30°～40°), and RDV-(40°～53°). The results of two groups of patients were compared.RESULTS: No significant differences were observed in RDV-(0°～10°), RDV-(10°～20°), RDV-(20°～30°), RDV-(30°～40°), RDV-(40°～53°)between the two groups at 3mo post-operation(all P&#x003E;0.05). Furthermore, the RDV-(20°～30°), RDV-(30°～40°)and RDV-(40°～53°)of the two groups at 3mo postoperatively were all significantly lower than those preoperatively(all P&#x003C;0.05). The changes in coma(horizontal)and spherical aberration(SA)at 3mo postoperatively were smaller in the SMILE group [0.106(0.056, 0.171)and 0.115(0.081, 0.182)μm] than in the FS-LASIK group [0.206(0.104, 0.355)and 0.197(0.128, 0.254)μm](Z=-4.170, -5.016, all P&#x003C;0.05). A negative correlation was found between postoperative SA and postoperative RDV-(10°～53°)(rs=-0.205, -0.181, -0.226, -0.244, all P&#x003C;0.05).CONCLUSION: Both FS-LASIK and SMILE reduced retinal hyperopic defocus in the peripapillary macular range of 20°～53° eccentricity, and the postoperative changes in coma(horizontal)and SA were smaller with SMILE than with FS-LASIK. There was a certain correlation between postoperative SA and postoperative retinal peripheral defocus.

Meta-analysis of repeated low-level red light therapy for retarding myopia progression in children / 中华实验眼科杂志

Objective:To systematically evaluate the effect of repeated low-level red light (RLRL) therapy on controlling the progression of myopia in children.Methods:Medline, Embase, Cochrane Library, Web of Science, ClinicalTrial.gov and the CNKI, VIP, Wanfang database, and Chinese Clinical Trial Registry (www.chictr.org.cn) were searched from their establishment to September 2022 to obtain the randomized controlled trial (RCT) about RLRL controlling myopia progression in children.Grey literature was also searched.Inclusion and exclusion criteria were developed according to the PICOS principle.Two researchers screened the literature independently, extracted data, and assessed the risk of bias in the included studies using the Cochrane collaboration tool for assessing risk of bias.The data were imported into RevMan 5.4 software for meta-analysis.Mean and standard deviation of data were used to obtain mean differences and 95% confidence intervals of included studies.Changes in spherical equivalent (SE) and axial length (AL) were compared between before and after the intervention in RLRL and single-vision spectacle (experimental group) and single-vision spectacle (control group). The GRADE system was used to grade the quality of evidence for the outcome indicators.Results:A total of 157 studies were obtained.After the screening, 7 RCT studies including 1 038 study subjects met the inclusion criteria.Meta-analysis results showed that retarded SE progression was retarded and AL elongation was reduced significantly after different follow-up durations (1, 3, 6, 12 and 24 months) in experimental group compared with control group.As the follow-up duration extended from 1 month to 24 months, the retard of SE progression increased from 0.14 to 0.93 D, and the reduction of AL increased from 0.07 to 0.48 mm.Both 635 and 650 nm red light significantly retarded SE progression and reduced AL elongation.The two outcome indicators, SE change and AL change were moderate-strength evidence by GRADE.Conclusions:The current moderate-strength evidence shows that RLRL can better retard myopia progression in children than single-vision spectacle glasses.

Inhibitory effects of 1% atropine on form deprivation-induced myopia development in guinea pigs and its mechanism / 中华实验眼科杂志

Objective:To observe the prevention and control effect of 1% atropine on the progression of form deprivation myopia (FDM) in guinea pigs and the potential biological mechanism.Methods:Sixty-nine 3-week-old tricolor guinea pigs with normal refraction were randomly divided into a normal control group ( n=19), a FDM group ( n=19), a FDM+ atropine group ( n=19), and an atropine group ( n=12). No intervention was given to guinea pigs in normal control group.The FDM model was established by covering the right eye of guinea pigs with a semitransparent latex facemask for 4 weeks in FDM and FDM+ atropine groups.For the FDM+ atropine group, 1% atropine gel was topically administered to the form-deprived right eyes once a day for 4 weeks.For the atropine group, the right eye was treated with 1% atropine gel once a day for 4 weeks.Refraction and axial length of guinea pigs were measured by retinoscopy and ophthalmic A-scan ultrasonography respectively at baseline, experiment week 2 and week 4.In experiment week 4, eyeballs were enucleated to make sections via the paraffin wax processing procedure, and the microstructural and ultrastructural changes of the sclera were observed under the light microscope and transmission electron microscope, respectively.The isobaric tags for relative and absolute quantitation labeling combined with liquid chromatography-tandem mass spectrometry were used to identify the differentially expressed proteins.Use and care of the animals complied with the Regulation for the Administration of Affairs Concerning Experiment Animals by State Science and Technology Commission.The study protocol was approved by the Institutional Animal Care and Use Committee of Tianjin Medical University (No.TJYY2020111028). Results:There were statistically significant differences in the diopter of guinea pigs at different time points among the four groups ( Fgroup=138.892, P<0.001; Ftime=167.270, P<0.001). Compared with normal control group, the diopter of guinea pigs in FDM group at experiment weeks 2 and 4, and FDM+ atropine group at experiment week 4 developed toward myopia, showing statistically significant differences (all at P<0.001). Compared with FDM group, the diopter of guinea pigs in FDM+ atropine group at experiment weeks 2 and 4 developed toward hyperopia, showing statistically significant differences (both at P<0.001). There were statistically significant differences in the axial length of guinea pigs at different time points among the four groups ( Fgroup=32.346, P<0.001; Ftime=353.797, P<0.001). The axial lengths of FDM group at experiment weeks 2 and 4 and FDM+ atropine group at experiment week 4 were longer than those of normal control group, and the axial lengths in FDM+ atropine group at experiment weeks 2 and 4 were shorter than those in FDM group, and the differences were statistically significant (all at P<0.001). The collagenous fibers of posterior sclera of guinea pigs were loose and disordered in FDM group, and were regular in FDM+ atropine group.The posterior scleral thickness of normal control group, FDM group, FDM+ atropine group and atropine group was (141.74±16.98), (101.46±9.15), (112.74±6.24) and (134.30±18.19) μm, respectively, with a statistically significant difference ( F=6.709, P=0.005). The posterior sclera was significantly thinner in FDM group than in normal control group and FDM+ atropine group (both at P<0.05). The diameter of posterior scleral collagen fiber gradually increased from inside to outside in normal control group, FDM+ atropine group and atropine group, and the diameters of the inner, middle and outer posterior scleral collagen fibers were smaller in FDM group than in normal control group.Proteomic analysis revealed 85 differentially expressed proteins (fold change>1.30) between FDM group and normal control group, FDM+ atropine group and FDM group, of which 38 were up-regulated and 47 were down-regulated after atropine treatment.Gene Ontology enrichment analysis showed that biological processes mainly involved were biological regulation, cell process, localization and metabolic process.Molecular function mainly involved were binding, catalytic activity, molecular function regulator, structural molecule activity and transporter activity.Cell components mainly involved were in cellular anatomical entity, intracellular and protein-containing complex. Conclusions:Atropine can increase the diameter of scleral collagen fibers in guinea pigs of FDM model, improve the arrangement of scleral collagen fiber, inhibit scleral thinning.The mechanism of atropine to control myopia progression is closely related to the tight junction between scleral cells, cytoskeleton and extracellular matrix remodeling.

Association of peripheral axial length, retinal curvature with refraction in school-aged children / 中华实验眼科杂志

Objective:To investigate the association of peripheral axial lengths and retinal curvatures with refractive status.Methods:A cross-sectional study was conducted out.Two hundred and eighty-seven eyes of 287 consecutive children aged 6-15 years old who recieved eye examinations at Beijing Tongren Hospital from July to October 2021 were enrolled, including 154 males and 133 females.Uncorrected and best corrected visual acuity were tested with a standard logarithmic visual acuity chart.Spherical equivalent (SE) was measured via an auto refractometer after cycloplegia with tropicamide.The hyperopic, emmetropic and myopic groups were defined with a SE >+ 0.5 D, SE >-0.5 D to ≤+ 0.5 D and SE≤-0.5 D, respectively.Central and 30° peripheral eye lengths (nasal, temporal, superior, inferior) were obtained using the Lenstar LS900.Retinal coordinates were derived from partial coherence interferometry modeling and converted to retinal curvatures.According to the median horizontal peripheral eye length differences (absolute difference between nasal and temporal), participants were assigned to H1 group (absolute difference <0.35 mm) or H2 group (absolute difference ≥0.35 mm). According to the median vertical peripheral eye length differences (absolute difference between superior and inferior), participants were assigned to V1 group (absolute difference <0.32 mm) or V2 group (absolute difference ≥0.32 mm). Four groups of V1H1, V1H2, V2H1 and V2H2 were constructed according to the grouping methods in both directions above.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Beijing Tongren Hospital, Capital Medical University (No.TRECKY2021-162). Written informed consent was obtained from guardians of each subject prior to any medical examination.Results:The central axial length was 23.53(22.93, 24.10)mm.Peripheral eye lengths of temporal, nasal, superior and inferior were 22.75(22.11, 23.22)mm, 22.99(22.32, 23.45)mm, 23.24(22.58, 23.75)mm and 23.12(22.52, 23.56)mm, respectively.Temporal eye length was shorter than nasal, showing a statistically significant difference ( Z=-3.58, P<0.01). Compared with H2 group, H1 group had shorter central, nasal, superior and inferior eye lengths, showing statistically significant differences (all at P<0.05). Compared with V2 group, V1 group had shorter central, nasal and superior eye lengths, showing statistically significant differences (all at P<0.05). SE of H1 group was + 0.06 (-1.06, + 0.75) D, which was significantly greater than -0.32 (-1.64, + 0.56) D of H2 group ( Z=-2.10, P=0.04). SE of V1 group was + 0.13 (-0.81, + 0.80) D, which was significantly greater than -0.56 (-1.83, + 0.48) D of H2 group ( Z=-3.39, P<0.01). The myopia ratio of V1 group was 33.5% (58/173), which was significantly lower than 50.5% (53/105) of V2 group ( χ2=7.83, P<0.01). There was a significant overall difference in SE among VIH1, V1H2, V2H1 and V2H2 groups ( H=24.79, P<0.01). SE was greater in V1H1 group than V1H2, V2H1 and V2H2 groups (all at P<0.01). There was a significant difference in both horizontal and vertical retinal curvatures among different refractive groups ( H=22.34, 19.30; both at P<0.01). The retical curvature in both directions of hyperopic and emmetropic groups were significantly larger than those of myopic group (both at P<0.01). Conclusions:Peripheral eye lengths are asymmetric in school-aged children.Higher asymmetry is associated with myopic shifts.Myopic children have a steeper retina than the hyperopic and emmetropic children.

Comparação entre os resultados do implante de um segmento de arco longo versus dois segmentos de arco tradicional no tratamento de pacientes com ceratocone / Comparison between the results of implanting a long-arch segment versus two standard arch segments for treatment of keratoconus patients

RESUMO Objetivo: Analisar retrospectivamente as alterações na ceratometria e no astigmatismo corneano obtidas após cirurgia de implante de anel intraestromal, comparando o uso de um segmento de arco longo versus o implante de dois segmentos de comprimento de arco tradicional. Métodos: A partir de um estudo transversal, obtivemos os dados de 94 olhos de pacientes diagnosticados com ceratocone, que foram submetidos ao implante de anel corneano. Eles foram divididos em dois grupos, dependendo do tipo de implante recebido: Grupo A, um segmento de arco longo; Grupo B, dois segmentos tradicionais. Todos os segmentos implantados possuíam 250µ de espessura. Os dados do pré-operatório dos dois grupos foram comparados, para garantir que as amostras eram similares (as diferenças encontradas entre os dois grupos não eram estatisticamente significativas). As variáveis analisadas no pré e no pós-operatório foram acuidade visual com correção, ceratometria, astigmatismo corneano e refração. Resultados: A amostra que recebeu apenas um segmento de arco longo (Grupo A) obteve redução da ceratometria média de 4,42D (8,7%) e do astigmatismo corneano de 2,43D (40,4%). Já na amostra dos olhos que receberam dois segmentos de arco tradicional (Grupo B), houve redução média de 2,66D (5,1%) em relação à ceratometria média e redução média de 2,11D (34,8%) em relação ao astigmatismo corneano. A redução obtida na ceratometria média no Grupo A foi maior que a obtida no Grupo B (diferença estatisticamente significativa). A redução obtida no astigmatismo do Grupo A não foi estatisticamente significante, se comparada com o resultado obtido no Grupo B (considerando p≤0,05). Conclusão: Foi demonstrado que o uso de um segmento de arco longo possui maior capacidade de aplanação corneana, se comparado com o uso de dois segmentos com comprimento de arco tradicional. Em relação à redução do astigmatismo, os dois grupos mostraram resultados equivalentes.

ABSTRACT Purpose: To retrospectively analyze the changes in corneal keratometry and astigmatism after intrastromal ring surgery, comparing the use of one long arch segment versus two traditional arc length segments. Methods: A cross-sectional study obtained data from 94 eyes of patients diagnosed with keratoconus that underwent surgical treatment with corneal ring implant. They were divided into two groups according to the type of implant received: one long-arch segment (Group A) or two traditional segments (Group B), both 250 microns thick. Preoperative data from the two groups were compared to ensure that the samples were similar (the differences between the two groups were not statistically significant). The variables (pre and post-operatively) analyzed were: best corrected visual acuity, keratometry, corneal astigmatism and refraction. Results: Group A, which received one long arch segment, showed a Km decrease of 4.42D (8.7%) and a corneal astigmatism reduction of 2.43D (40.4%). Group B, where the eyes acquired two traditional arch segments, showed an average Km decrease of 2.66D (5.1%) and corneal astigmatism reduction of 2.11D (34.8%). The mean keratometry (Km) reduction obtained was statistically significant (p≤0.05) when comparing both groups (A and B). The mean corneal astigmatism reduction was not statistically significant (p≤0.05) when comparing both groups (A and B). Conclusions: One long-arch segment has been demonstrated to have a greater capacity to reduce corneal curvature when compared to the use of two traditional-sized arch segments. No significant differences were found regarding the reduction of corneal astigmatism after comparing the results obtained in both groups.

Stabilization of refraction and timing of spectacle prescription following manual small-incision cataract surgery

Purpose: To determine the stabilization of refraction at 2 weeks following MSICS by comparing the difference in spherical, cylindrical component and also spherical equivalent of refraction of 2 weeks follow-up with that of 6 weeks following surgery. Methods: The difference of spherical, cylindrical component and also spherical equivalent of refraction at 2 weeks and 6 weeks follow-up of 194 eyes that underwent uncomplicated MSICS with implantation of PMMA IOL conducted by a single experienced surgeon were compared to find out the amount of change and its significance was statistically tested by Wilcoxon-Signed Rank Test. Results: The difference in spherical power (0.04 � 0.30), cylinder power (0.03 � 0.40), and spherical equivalent (0.06 � 0.34) were very small and not significant statistically (P-value ?0.05). Conclusion: Necessary spectacle correction can safely be prescribed after 2 weeks following MSICS as subjective refraction stabilizes by that time without undergoing significant change. However, our observation was applicable in patients who had an uneventful cataract surgery without any risk factor, which can delay wound healing or cause poor visual outcome.

Comparing the vision quality using double-pass technique in eyes with corrected refractive errors and emmetropic eyes / Comparação da qualidade óptica usando a técnica de dupla passagem em olhos com erros de refração corrigidos e olhos emetrópicos

ABSTRACT Purpose: To evaluate the vision quality by measuring the objective light scatter index and objective optical quality parameters (Strehl Ratio and Modulation Transfer Function) in patients with emmetropia and ametropia. Methods: This prospective, cross-sectional study included 408 eyes. The ametropic group comprised of eyes with best-corrected visual acuity of 0.0 logMAR or better and present at least a refractive error of ≥0.25 D. Patients underwent slit lamp examination, visual acuity, refraction, and vision quality using the HD Analyzer. Results: The mean objective light scatter indices were 0.62 ± 0.63, 0.77 ± 0.70, 0.74 ± 0.30, 0.93 ± 0.55, and 0.85 ± 0.61, and mean Strehl Ratio and Modulation Transfer Function scores were 38.17 ± 10.4, 37.37 ± 10.06, 29.84 ± 9.71, 33.2 ± 12.11, and 33.13 ± 10.09 in emmetropes, myopia, hyperopia, spherical equivalent of ≥0, and spherical equivalent of <0, respectively. Differences in all variables were significant between emmetropic and corrected hyperopic and between spherical equivalent of ≥0, and spherical equivalent of <0 eyes (p<0.05). Conclusion: In spectacle-corrected conditions (with trial frames), emmetropic and simple myopic eyes had significantly better vision quality compared to hyperopic and astigmatic eyes. The clinical significance of these results should be investigated in further studies.

RESUMO Objetivo: Avaliar a qualidade óptica medindo o índice de dispersão objetiva de luz e os parâmetros de qualidade óptica objetiva (Razão de Strehl e Função de Transferência de Modulação) em indivíduos com emetropia e ametropia. Métodos: Estudo prospectivo, transversal, incluindo 408 olhos. O grupo ametrópico era de olhos com melhor acuidade visual corrigida de 0,0 logMAR ou melhor e apresentando, pelo menos, um erro refrativo de 0,25 D ou mais. Os pacientes foram submetidos a exame com lâmpada de fenda, acuidade visual, refração e qualidade óptica com o HD Analyzer. Resultados: O índice de dispersão objetiva de luz médio foi de 0,62 ± 0,63, 0,77 ± 0,70, 0,74 ± 0,30, 0,93 ± 0,55, 0,85 ± 0,61 e a média da Razão de Strehl e de Função de Transferência de Modulação foram 38,17 ± 10,4, 37,37 ± 10,06, 29,84 ± 9,71, 33,2 ± 12,11 e 33,13 ± 10,09 em olhos emetrópicos, míopes, hipermétropes, equivalente esférico ≥0 e equivalente esférico <0 respectivamente. Foram encontradas diferenças significativas em todas as variáveis entre olhos emetrópicos e com hipermetropia corrigida, equivalente esférico ≥ 0 e equivalente esférico <0 (p<0,05). Conclusão: Em condições com lentes corrigidas (com armações de prova), os olhos emetrópicos e com miopia simples apresentaram qualidade óptica significativamente melhor em comparação com os olhos hipermétropes e astigmáticos. O significado clínico destes resultados deve ser estudado posteriormente.

The Pentacam® AXL Wave provides a reliable wavefront-based objective refraction when compared to manifest subjective refraction: A prospective study

Purpose: Accurate refraction is arguably the most important parameter for a successful laser vision correction surgery and is based on a combination of manifest and cycloplegic refraction. Wavefront?based objective refraction may be useful in the evaluation of patients. So far, the reliability of objective refraction as measured using the Pentacam® AXL Wave has not been published in the literature. Methods: This was a prospective study including a total of 168 eyes belonging to 84 young non?presbyopic patients evaluated for refractive surgery. Pentacam® AXL Wave full sequence was taken for all patients. Then, a clinician who was unaware of the objective refraction results performed a full physical examination, including manifest refraction starting from an autorefractometer value. All refraction values were transferred to astigmatic power vectors as per the Thibos method. Reliability of the different vectors and a unifying blur value were compared using Spearman correlation, Bland–Altman plot, and intraclass correlation coefficient. Results: The mean age was 28.8 ± 5.4 years, with a female preponderance (60.7%). The correlation between both eyes was high. The difference in M vector between subjective and objective refraction was 0.16 D, while the difference was 0.04 and 0.01 D for the J0 and J45 vectors, respectively. Paired samples Student t was non?significant for all comparisons. Spearman rho correlations were high (0.666–0.924, all P < 0.001). Intraclass correlation coefficients were also high (0.890–0.966). Bland–Altman plots did not demonstrate any systematic errors. Conclusion: Wavefront?based refractive refraction obtained using the Pentacam® AXL Wave is highly agreeable and correlated with measurements obtained by manifest subjective refraction.

A comparative study of knotless versus knotted transscleral suture-fixated intraocular lens implantation

Purpose: To compare functional outcomes and complication rates of two scleral fixated intraocular lens implantation (SFIOL) techniques. Methods: In this retrospective study, there were 30 eyes of 30 patients who underwent SFIOL implantation for dislocation of the IOL or crystalline lens. Group 1 (n = 17) comprised patients who received scleral?fixated polymethylmethacrylate (PMMA) IOL implantation through a self?sealing sclerocorneal tunnel with the suture burial technique, and group 2 (n = 13) comprised patients who received scleral?fixated foldable acrylic IOL implantation with a cartridge using a self?sealing clear corneal incision (CCI) with knotless Z?suture technique between 2014 and 2019. Surgical outcomes concerning safety, efficiency, visual function, induced astigmatism with vector analysis, and complications were compared. Results: The indications were dislocated crystalline lens (n = 5/30), dislocated IOL (n = 17/30), and dropped nucleus (n = 8/30). The mean follow?up time was 50.65 ± 14.02 months in group 1 and 15.69 ± 3.71 months in group 2 (P < 0.001). The postoperative visual acuity improvement was statistically significant in both groups (P < 0.001). Surgically induced astigmatism was significantly higher in group 1 (2.68 ± 1.04 D) compared with group 2 (1.6 ± 1.0 D) at month 12 (P = 0.001). Postoperative complications included suture exposure (n = 1 in group 1) and cystoid macular edema (n = 1 in group 1; n = 1 in group 2). Conclusion: Both SFIOL techniques are safe and effective in the absence of adequate capsular support. However, the knotless Z?suture technique appears to be superior to the suture burial technique with regard to suture exposure?related complications. In addition, self?sealing CCI appears to be superior to self?sealing sclerocorneal tunnel with regard to surgically induced astigmatism

Effects of different intensity of lighting on refractive development and form deprivation myopia in guinea pigs / 中华实验眼科杂志

Objective:To investigate the effects of different intensity of lighting on normal refractive development and form deprivation myopia (FDM) in guinea pigs.Methods:A total of 108 healthy 3-week-old guinea pigs were divided into normal refractive development guinea pigs ( n=54) and FDM guinea pigs ( n=54). FDM models were prepared in FDM animals by occlusion of the left eyes using an opaque mask, and the bilateral eyes were open in the normal refractive development guinea pigs.The guinea pigs were randomized to low (20 lx), normal(300 lx), and high intensity-lighting (5 000 lx) groups with a 12-hour light/12-hour dark cycle for 6 consecutive weeks under LED light.The ocular biometry was performed in a two-week interval.Axial length (AL) and dilated diopter were measured by A-scan ultrasonography and retinoscopy, respectively, and were compared after different lighting durations, and the change trends of them in normal refractive development and FDM guinea pigs were evaluated. Results:The AL values were not significantly different among low, normal and high intensity-lighting groups ( Fgroup=0.365, P=0.697), and the AL was gradually prolonged over the lighting duration ( Ftime=353.750, P<0.001). The diopters showed a statistically significant difference among different intensity-lighting groups ( Fgroup=3.576, P=0.034). The diopter in high intensity-lighting for 4 weeks was (+ 2.75±2.15) D, which was significantly higher than (0.41±3.07) D in the normal refrective development guinea pigs ( P<0.001). In the FDM guinea pigs, both AL and diopter were not significantly different among low, normal and high intensity-lighting groups ( Fgroup=0.105, P=0.900; Fgroup=0.973, P=0.387), and significant differences were seen in AL and diopter among three groups ( Ftime=408.302, 27.407; both at P<0.001). The diopter in FDM eyes of low intensity-lighting for 2 weeks was (+ 2.35±1.95) D, which was higher than (+ 1.90±0.97) D before lighting, with no statistically significant difference between them ( P>0.05). The AL was shortest and the AL change was smallest in normal refractive development guinea pigs of high intensity-lighting group.The diopter change in FDM guinea pigs of the low intensity-lighting group was significantly smaller than that in the normal intensity-lighting group ( P<0.001), with a transient hyperopia drift. Conclusions:The 5 000 lx lighting can slow down the development toward myopia in the normal refractive development eyes, and 20 lx lighting tends to delay the progression FDM eyes with a hyperopic shift after lighting for 2 weeks.

Analysis of refractive status of preschool children in Suzhou High tech Zone / 中国学校卫生

Objective@#To observe the refractive status of preschool children, and to explore the prevalence and development trend of ametropia in preschool children, so as to provide support for controlling adolescent ametropia and improving children s health care service.@*Methods@#This cross sectional survey was conducted among 27 561 preschool children (55 122 eyes) aged 3-6 years old in the High tech Zone of Suzhou from September to December 2020. The refractive status was screened by the US Weilun binocular optometry.@*Results@#The total detection rate of ametropia was 9.5%, including 8.6% of astigmatism, 1.3% of hyperopia and 0.5% of myopia. The detection rates of myopia (1.1%) and hyperopia (2.2%) were the highest in the 6-year-old group, and the older the age was, the lower the spherical diopter was, and the higher the cylindrical diopter was. The abnormal rate of colposcopy in girls ( 1.3% ) was higher than that in boys (0.9%), and the abnormal rate of total anisometropia in women (2.3%) was also higher than that in men (1.9%). The main astigmatism was mixed astigmatism (49.1%) and compound hyperopia astigmatism (39.2%); The older the age, the lower the detection rate of compound hyperopia astigmatism. And it is dominated by regular astigmatism( 97.5% ); The higher the age, the higher the detection rate of astigmatism with the rule, while the lower the detection rates of astigmatism against the rule and oblique axis astigmatism.@*Conclusion@#The detection rate of myopia and hyperopia increased significantly at the age of 6, and anisometropia and axial astigmatism also reached the highest at the age of 6. Local health care departments should pay attention to children s astigmatism, especially astigmatism with the rule.

Effects of environmental factors on refractive development of children and adolescents in different pubertal stages / 中国学校卫生

Objective@#To explore the effect of puberty on refractive development of children and adolescents and its interaction with outdoor activities, near work and the use of electronic products, so as to provide a reference for strategies for intervening myopia.@*Methods@#Cluster sampling method was used to select 776 students aged 7-13 from a nine year consistent school in Shanghai to participate and were followed up for 2 years. All participants underwent cycloplegic refraction and ocular axial length measurement once a year, as well as pubertal development, average daily outdoor time, near work time and time of electronic products usage. The influencing factors and interaction effects of refractive parameters in different puberty stages were analyzed by generalized estimation equation.@*Results@#At baseline, 634 children participated in cycloplegic refraction, of which 350 were myopic (55.2%). There were significant differences in axial length, average daily outdoor time, near work time and time of using electronic products at different stages of puberty ( F = 4.10 ，4.24，5.54，9.20， P <0.05). There was interaction between puberty and outdoor time on axial length development ( β =0.133, P < 0.05), and the interaction between puberty and the time of near work or using electronic products was not statistically significant ( P >0.05).@*Conclusion@#Puberty may play a regulatory role in the relationship between outdoor time and refractive development among Chinese children and adolescents.

Clinical characteristics of acute acquired comitant esotropia / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM:To describe the clinical characteristics of 20 patients with acute acquired comitant esotropia(AACE). <p>METHODS: This retrospective, observational case series study enrolled patients with AACE examined from June 2018 to May 2021 in Guangdong Jiangmen Central Hospital. The age when attacked, the duration of excessive near work before illness, symptom, refraction, AC/A, deviation and near stereopsis were analyzed. All 20 patients had unremarkable neurological finding by imageological test. <p>RESULTS: Most patients whose mean age was 24.25±5.78 years immersed in near work for more than 6h a day before illness. All patients seeked for medical help because diplopia with normal ocular motility in all directions of gaze and meaningless finding in routine ophthalmologic examinations. They were all nearsightedness whose mean spherical equivalent was -5.73±5.09D, while mean AC/A was 2.65±1.16 within the upper limit. There was no different between the distant and near deviations(<i>P</i>>0.05). Deviations might be correlated with near stereopsis(<i>P</i><0.05), however the duration from onset to treatment was irrelevant(<i>P</i>>0.05).<p>CONCLUSION: The clinical features of AACE in older children and adults who immersed excessive near work are medium myopia, diplopia, normal ocular motility, no neurological finding and limited AC/A. Moreover, it is approximate between distant and near deviations. The deviations affect near stereopsisd more, while the influence of duration from onset to treatment may be less.

Refractive changes after intraocular lens implantation in post-cataract extraction children in a Philippine Tertiary Hospital

Objective@#To determine refractive changes in children post-cataract extraction and intraocular lens (IOL) implantation at a Philippine tertiary hospital. @*Methods@#This is a retrospective cohort study involving patients aged 1 to 10 years in the Department of Ophthalmology of a Philippine tertiary hospital who underwent cataract extraction and IOL implantation between 2004 to 2013. @*Results@#We included 55 eyes of 34 patients in the analysis. Thirty-eight eyes (69%) eyes underwent primary IOL implantation. The mean duration of follow-up was 3.5 ± 2.1 years. The median refractive changes were -2.00 (-2.50, -0.50) diopters (D) for the 1- to 3-year-old group, -1.25 (-1.50, -0.25) D for the 4- to 7-year-old group, and -1.00 (-1.63, -0.25) D for the 8- to 10-year-old group. Only the 1- to 3-year-old group had significant difference between the initial post-operative refraction and the latest follow-up refraction (p<0.001). For the primary implantation group, patients in the 1- to 3-year-old group had the highest median refractive change at -2.00 (-3.125, -1.00) D while patients in the 8- to 10-year-old group had the highest median refractive change at -2.12 (-2.56, -1.69) D in the secondary implantation group. Refractions of eyes with IOL-implanted and normal eyes showed a median difference of -1.00 (-0.25, -3.5) D. @*Conclusion@#The determination of the power of IOL implants in pediatric patients who underwent cataract extraction remains challenging despite availability of recommendations.