The effect of individualized ocular refraction customized spectacle lenses on myopia control in schoolchildren: A 1-year randomised clinical trial.

PURPOSE: The aim of this study was to investigate the effect of individualized ocular refraction customized (IORC) spectacle lenses with different actual amounts of peripheral myopic defocus (MD) on myopia control over 1 year. These lenses compensate for the original peripheral refraction via the free-form surface on the back of the lens. METHODS: This 1-year, double-masked randomised clinical trial included 184 myopic schoolchildren aged 8-12 years. Participants were randomised to receive IORC lenses with high (IORC-H group, +4.50 D), medium (IORC-M group, +3.50 D) or low (IORC-L group, +2.50 D) MD or single-vision (SV) lenses. The spherical equivalent refractive error (SER) and axial length (AL) were measured at baseline and 6-monthly intervals. RESULTS: After 1 year, the mean (SD) changes in SER were -0.18 (0.37), -0.36 (0.37), -0.52 (0.39) and -0.60 (0.42) D for the IORC-H, IORC-M, IORC-L and SV groups, respectively. Compared with the SV group, the effects of slowing myopia progression were 70%, 40% and 13% for the IORC-H (difference of 0.47 D, p < 0.001), IORC-M (difference of 0.32 D, p = 0.001) and IORC-L (difference of 0.15 D, p > 0.05) groups, respectively. The mean (SD) changes in AL were 0.12 (0.16), 0.23 (0.17), 0.29 (0.17) and 0.36 (0.17) mm for the IORC-H, IORC-M, IORC-L and SV groups, respectively. The axial elongation was 67%, 36% and 19% lower in the IORC-H (difference of 0.25 mm, p < 0.001), IORC-M (difference of 0.15 mm, p < 0.001) and IORC-L (difference of 0.10 mm, p = 0.04) groups, respectively, compared with the SV group. The IORC-H group exhibited significantly less axial elongation than the IORC-M and IORC-L groups (p = 0.01 and p < 0.001, respectively). CONCLUSION: Compared with the IORC-M and IORC-L lenses, the IORC-H lens was found to have superior efficacy in inhibiting myopic progression and slowing eye growth in schoolchildren, with better myopia control efficacy in younger children.

Evaluation of objective and subjective binocular ocular refraction with looking in type.

BACKGROUND: This study aimed to compare the results of the Chronos binocular/monocular refraction system, that measures objective and subjective ocular refraction in one unit, to objective findings obtained from a conventional autorefractometer and a conventional subjective ocular refraction using a trial-frame in real space. METHODS: Twenty-eight healthy volunteers (21.2 ± 1.5 years old) were included in this study. Objective ocular refraction was measured using two tests: the Chronos binocular/monocular refraction system under binocular conditions and a conventional autorefractometer under monocular conditions. Subjective ocular refraction was measured using three tests: Chronos binocular/monocular refraction system under binocular, monocular conditions, and trial-frame in the real space under monocular conditions. The measurement distance was set to 5.0 m for each test. All ocular refractions were converted into spherical equivalents (SEs). RESULTS: The objective SE was significantly more negative with Chronos binocular/monocular refraction system under binocular condition (- 4.08 ± 2.76 D) than with the conventional autorefractometer under monocular condition (- 3.85 ± 2.66 D) (P = 0.002). Although, the subjective SE was significantly more negative with Chronos binocular/monocular refraction system under binocular condition (- 3.55 ± 2.67 D) than with the trial-frame in the real space under monocular condition (- 3.33 ± 2.75 D) (P = 0.002), Chronos binocular/monocular refraction system under monocular condition (- 3.17 ± 2.57 D) was not significantly different from that in trial-frame in real space under monocular condition (P = 0.33). CONCLUSION: These findings suggest that the Chronos binocular/monocular refraction system, which can complete both objective and subjective ocular refraction tests in a single unit, is suitable for screening ocular refraction, although it produces slightly more myopic results. Furthermore, subjective ocular refraction testing accuracy in Chronos binocular/monocular refraction system can be equivalent to trial-frame in real-space testing by switching from binocular to monocular condition.

Comparison of refractometric measurements obtained with a portable autorefractor and conventional methods of refraction in schoolchildren / Comparação de medidas refratométricas obtidas com autorrefrator portátil e métodos convencionais de refração em escolares

ABSTRACT Objective: To assess the performance of a portable autorefractor as refractor and screening tool for refractive errors in schoolchildren. Methods: Cross-sectional observational study. Refractometric measurements of children between 5 and 10 years old were obtained through four methods: 2WIN under non-cycloplegic conditions, and 2WIN, conventional autorefractor, and retinoscopy, under cycloplegic conditions. Correlations and agreement between the methods and accuracy of the portable autorefractor to define whether to prescribe glasses were assessed. Results: The mean age ± standard deviation was 6.87 ± 1.42 years. The portable autorefractor without cycloplegia showed a high correlation with retinoscopy (0.77) but tended to underestimate hyperopia and overestimate high astigmatism. Regarding screening for prescription of glasses in comparison with the reference method "retinoscopy," the sensitivity of the portable autorefractor without cycloplegia was calculated to be 100,00% and the specificity, 34.3%. Conclusion: The portable autorefractor should be used as a screening tool and, when prescribing glasses, the tendency of underestimating hyperopia and overestimating high astigmatism should be kept in mind.

RESUMO Objetivo: Avaliar o desempenho de um autorrefrator portátil como refrator e ferramenta de triagem para erros de refração em crianças em idade escolar. Métodos: Estudo observacional transversal. As medidas refratométricas de crianças de 5 a 10 anos foram obtidas por meio de quatro métodos: 2WIN em condições não cicloplégicas e 2WIN, autorrefrator convencional e retinoscopia, em condições cicloplégicas. Foram avaliadas as correlações e a concordância entre os métodos e a acurácia do autorrefrator portátil para definir a prescrição de óculos. Resultados: A média de idade ± desvio-padrão foi de 6,87 ± 1,42 anos. O autorrefrator portátil sem cicloplegia apresentou alta correlação com a retinoscopia (0,77), mas tendeu a subestimar a hipermetropia e a superestimar o alto astigmatismo. Em relação à triagem para prescrição de óculos em comparação com o método de referência retinoscópio, a sensibilidade do autorrefrator portátil sem cicloplegia foi calculada em 100,00% e a especificidade, em 34,3%. Conclusão: O autorrefrator portátil deve ser usado como ferramenta de triagem e, ao se prescreverem óculos, deve-se ter em mente a tendência de subestimar a hipermetropia e superestimar o alto astigmatismo.

Comparison between wavefront-derived refraction and auto-refraction.

BACKGROUND: This study aimed to compare objective refractive errors and keratometry measurements obtained using the Nidek OPD-Scan II aberrometer/topographer and Topcon KR 8900 autorefractokeratometer. METHODS: The right eye medical records of 176 patients aged 18-35 years who were admitted to our clinic as refractive surgery candidates were tested for refractive status and keratometry measurements with a Nidek OPD-Scan II aberrometer/topographer and a standard table-top autorefractokeratometer (Topcon KR 8900) before and after the induction of cycloplegia. Patients who had undergone any eye surgery and had hereditary, ectatic, or acquired corneal pathology were excluded. Refractive data were compared as spheres, cylinders, spherical equivalents, and power vectors before and after the induction of cycloplegia. Flat and steep keratometry (K1-K2) readings were recorded in diopters (D) and axis degrees, respectively, for each eye. RESULTS: The spherical, cylindrical, spherical equivalence, J0-J45 vector values and K1-K2 readings (D, axis) between the two devices were statistically significant before and after the induction of cycloplegia (p<0.05). Bland-Altman analysis identified mean differences (95%CI of limits of agreement) of 0.77 (-0,57 to 2,11) in sphere, 0.74 (-0,54 to 2,01) in spherical equivalent, -0,07 (-0,41 to 0,26) in J0 vector, 0,06 (-0,31 to 0,43) in J45 vector, -0,16 (-0,66 to 0,33) in K1, -0,23 (-0,79 to 0,33) in K2 values before induction of cycloplegia. CONCLUSION: The refractive and keratometry results of the Nidek OPD Scan II system and Topcon KR 8900 standard table-top autorefractokeratometer are not interchangeable in healthy adult population before and after induction of cycloplegia.

Myopia progression in school children with prolonged screen time during the coronavirus disease confinement.

Background: Myopia, the most common refractive error, is a global public health problem with substantial visual impairment if left untreated. Several studies have investigated the association between increased near-work and restricted outdoor activities in children with myopia; however, such studies in children without myopia are scarce. We aimed to monitor the effect of the coronavirus disease-2019 (COVID-19) home confinement and mandatory virtual learning on myopic progression among myopic and non-myopic school-aged children. Methods: We conducted a retrospective chart review of children aged 6 - 12 years attending regular visits to the pediatric ophthalmology clinic in a tertiary eye hospital in Eastern Province, Saudi Arabia. Cycloplegic refraction was determined from three visits at least six months apart: two visits before the start of the COVID-19 pandemic and one during the COVID-19 home confinement. Parents were asked about the time spent in near-work and outdoor activities, the devices used during virtual learning, and the demographic characteristics of the children. Statistical analyses were conducted to compare myopia progression before and during the COVID-19 home confinement. Results: A total of 160 eyes of 80 children were analyzed. The boy (n = 46) to girl (n = 34) ratio was 1.4:1. The hyperopia (n = 131 eyes) to myopia (n = 29 eyes) ratio was 4.5:1. Most eyes exhibited a hyperopic shift before the confinement; however, all eyes displayed a myopic shift during the confinement. When comparing both eyes of the same individual, the more myopic or less hyperopic eye in the same child had a significantly greater myopic shift than the fellow eye (both P < 0.05). Children who used tablets showed a significant myopic shift (P < 0.05). Likewise, children in both age categories ( ≤ 8 and > 8 years), boys, those living in an apartment, and those having parents with bachelor's degrees experienced a significant myopic shift during COVID-19 home confinement compared to before (all P < 0.05). The mean myopic shift was greater in children aged > 8 years than in those aged ≤ 8 years. Children with and without a family history of myopia had a myopic shift in the mean spherical equivalent during COVID-19 home confinement; however, that of children with no family history was statistically significant (P < 0.05). Conclusions: Progression of myopia accelerated in children during the COVID-19 pandemic. Excessive time spent on digital screen devices at near distances is considered a substantial environmental contributor to myopic shift in children. Further multicenter studies with extended follow-up periods are needed to assess the factors contributing to myopic progression in our population.

Outcomes of the Q value-based nomogram in managing pediatric versus adult keratoconus: a prospective interventional study.

Background: Keratoconus (KCN) is an ectatic disorder of the cornea characterized by stromal weakness and apical protrusion of the cornea, and is associated with a gradual and painless reduction in visual acuity. KCN in pediatric patients has certain important characteristics, such as a progressive and aggressive nature. We aimed to analyze the visual, refractive, and topographic outcomes of implanting a single 210° arc-length Keraring segment according to a novel, objective, Q value-based nomogram (Q-N) for the treatment of pediatric versus adult KCN. Methods: This prospective, multicenter, non-randomized, open-label trial included 47 eyes of 47 patients who were allocated to one of two groups. The adult group included 33 eyes of patients ≥ 18 years of age, whereas the pediatric group included 14 eyes of patients aged 14 - 17 years. All patients underwent femtosecond laser-assisted implantation of a single 210° arc-length Keraring segment according to the Q-N and were followed up for 6 months. All eyes underwent visual acuity measurement, cycloplegic refraction, and corneal topography at baseline and 6 months after surgery. Results: The study groups were comparable in terms of sex proportions and KCN grades (both P > 0.05). The adult group exhibited significant postoperative improvements in mean uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), sphere, cylinder, spherical equivalent (SE), and Kmax (all P < 0.001) with a mean change of -0.56 logarithm of the minimal angle of resolution (logMAR), - 0.40 logMAR, 3.07 diopters (D), 0.70 D, 3.42 D, and - 5.26 D, respectively. The pediatric group exhibited significant postoperative improvements in mean UDVA, CDVA, sphere, SE, and Kmax (all P < 0.05) with a mean change of - 0.62 logMAR, - 0.34 logMAR, 3.18 D, 3.67 D, and - 5.37 D, respectively. There were no significant differences between the groups in terms of the mean change in visual, refractive, and topographic variables (all P > 0.05). No postoperative complications were observed in either group. Conclusions: Use of the objective Q-N was efficient in the treatment of pediatric KCN, with postoperative improvements in the mean visual, refractive, and topographic parameters, comparable to outcomes in adult keratoconus. Q-N achieved good corneal remodeling with subsequent improvements in visual, refractive, and topographic outcomes in both adult and pediatric patients with keratoconus. To verify our preliminary findings, we recommend further multicenter randomized clinical trials using the Q-N nomogram in a larger sample of pediatric patients with KCN as an adjunct treatment before or after CXL.

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.

Safety and efficacy of implantable phakic contact lens versus implantable collamer lens in myopia correction.

Background: Phakic intraocular lenses (pIOLs) have proven to be excellent substitutes for excimer laser keratorefractive surgery in certain situations. We aimed to assess the efficacy and safety of two pIOLs, the implantable collamer lens (ICL V4c) versus the implantable phakic contact lens (IPCL V2), for myopic correction. Methods: In this prospective randomized clinical trial, we allocated eligible eyes with myopia > - 6 diopters into IPCL or ICL implantation groups, each including 100 eyes of 100 individuals. Preoperative and postoperative assessments at 3, 6, and 12 months included measurements of the spherical equivalent (SE), uncorrected distance visual acuity (UCDVA), best-corrected distance visual acuity (BCDVA), intraocular pressure (IOP), maximum keratometry (K1), minimum keratometry (K2), mean keratometry (Kmean), anterior chamber depth (ACD), anterior chamber angle (ACA), and endothelial cell density (ECD). Results: The groups had comparable demographic characteristics and baseline visual and anatomical values (all P > 0.05). The UCDVA, BCDVA, and SE of the two groups were comparable at baseline and at all postoperative follow-up examinations (all P > 0.05). Both groups experienced significant improvements in UCDVA, BCDVA, and SE at three months postoperatively (all P = 0.001), and measurements remained stable for up to 12 months. Keratometry readings were comparable between the groups over the follow-up period and remained unchanged at all visits (all P > 0.05). The ACA in the ICL group was significantly decreased at three months postoperatively (P = 0.001) and then widened significantly at 6 and 12 months (both P = 0.001). In the IPCL group, the postoperative ACA was significantly decreased at three months (P = 0.001) and was comparable to that in the ICL group (P > 0.01). However, at the 6- and 12-month postoperative visits, the ACA was significantly narrower in the IPCL group than in the ICL group (both P = 0.001). The ACD in both groups was decreased at three months postoperatively (both P = 0.001) and remained stable until the end of the study. The ECD remained comparable between the groups at all postoperative visits (all P > 0.05). We did not observe a significant ECD reduction in either group at any postoperative follow-up visit (all P > 0.05). We encountered no serious complications in either group. Conclusions: ICL and IPCL had comparable safety and efficacy outcomes in terms of anterior chamber morphometrics, visual and refractive results, and corneal parameters. Further multicenter randomized clinical trials with longer follow-up periods, larger sample sizes, and measurement of additional anterior chamber and corneal morphometrics, vault, and other vision parameters are needed to verify these findings.

Identification of ocular refraction based on deep learning algorithm as a novel retinoscopy method.

BACKGROUND: The evaluation of refraction is indispensable in ophthalmic clinics, generally requiring a refractor or retinoscopy under cycloplegia. Retinal fundus photographs (RFPs) supply a wealth of information related to the human eye and might provide a promising approach that is more convenient and objective. Here, we aimed to develop and validate a fusion model-based deep learning system (FMDLS) to identify ocular refraction via RFPs and compare with the cycloplegic refraction. In this population-based comparative study, we retrospectively collected 11,973 RFPs from May 1, 2020 to November 20, 2021. The performance of the regression models for sphere and cylinder was evaluated using mean absolute error (MAE). The accuracy, sensitivity, specificity, area under the receiver operating characteristic curve, and F1-score were used to evaluate the classification model of the cylinder axis. RESULTS: Overall, 7873 RFPs were retained for analysis. For sphere and cylinder, the MAE values between the FMDLS and cycloplegic refraction were 0.50 D and 0.31 D, representing an increase of 29.41% and 26.67%, respectively, when compared with the single models. The correlation coefficients (r) were 0.949 and 0.807, respectively. For axis analysis, the accuracy, specificity, sensitivity, and area under the curve value of the classification model were 0.89, 0.941, 0.882, and 0.814, respectively, and the F1-score was 0.88. CONCLUSIONS: The FMDLS successfully identified the ocular refraction in sphere, cylinder, and axis, and showed good agreement with the cycloplegic refraction. The RFPs can provide not only comprehensive fundus information but also the refractive state of the eye, highlighting their potential clinical value.

Effects of General Anesthesia on Ocular Refraction.

PURPOSE: General anesthesia alters the autonomic nervous system. This study aimed to investigate the effects of general anesthesia on objective ocular refraction. METHODS: A total of 57 patients (112 eyes) under 15 years of age who underwent strabismus surgery under general anesthesia were included in this study. Objective refraction values, corneal refraction values, and pupil diameter were measured using a HandyRef-K, a hand-held refractive keratometer, in the operating room before and during general anesthesia before strabismus surgery. RESULTS: The spherical power of the myopic eye increased from -0.75 D to -2.29 D (diopter); the cylindrical power increased from -0.90 D to -1.39 D (p < .01 for all). The corneal refractive power decreased by an average of 0.25 D (p < .01). The spherical refractive power was negatively correlated with the age and the amount of change between cycloplegia before general anesthesia and during general anesthesia (r = -0.32, p < .05). CONCLUSIONS: General anesthesia resulted in manifestation of myopia as noted by the objective refraction values. Corneal refractive values flatten under the same conditions, suggesting that the contraction of the ciliary muscles was the main cause of myopia. We speculate that this change was due to parasympathetic dominance and contraction of the ciliary muscles during general anesthesia.

Refractive changes with post-rotatory nystagmus in healthy individuals.

PURPOSE: Post-rotatory nystagmus has been used to detect autism spectrum disorders in clinical settings. Although previous studies have focused on eye movements, they did not evaluate the change in ocular refraction during post-rotatory nystagmus. This study aimed to evaluate the changes in ocular refraction during post-rotatory nystagmus in healthy individuals. METHODS: A total of 34 healthy volunteers (mean age ± standard deviation, 20.9 ± 0.6 years) participated in this study. The ocular refraction during post-rotatory nystagmus was measured using MR-6000 (Tomey Inc.) on quick mode with a sampling rate of 30 Hz under noncycloplegic and cycloplegic conditions. The amplitude of post-rotatory nystagmus was calculated on the basis of the anterior eye images, while the ocular refraction measurements were simultaneously recorded. The accommodative convergence per accommodation ratio was calculated using the heterophoria method. Video oculography was performed to measure the angle of convergence during post-rotatory nystagmus. RESULTS: The changes in ocular refraction during post-rotatory nystagmus were significantly greater under the noncycloplegic condition than under the cycloplegic condition. The changes in ocular refraction during the post-rotatory nystagmus were significantly and positively correlated with the amplitude of post-rotatory nystagmus under the noncycloplegic condition. The angle of convergence during post-rotatory nystagmus was significantly higher under the noncycloplegic condition than under the cycloplegic condition. The changes in the angle of convergence were significantly and positively correlated with the predicted accommodative convergence. CONCLUSIONS: These findings suggest that the accommodation was functional during the post-rotatory nystagmus to compensate for the retinal image slip, and the accommodative convergence can help weaken the nystagmus.

Benefits of using corneal topography to choose subjective refraction technique in keratoconus (RE-CON): a prospective comparative crossover clinical study.

PURPOSE: In prospective no-masking, comparative, crossover monocenter clinical trial, we aimed to evaluate whether the optimal subjective refraction technique varies with the keratoconus topography and to identify relevant topographic criteria. METHOD: This study included 72 keratoconus eyes with impaired visual acuity. Each eye tested three methods of refraction (Jackson cylinder, astigmatism dial, stenopeic slit), resulting in three eyeglass lenses. Patients were assigned to the group corresponding to the eyeglass lens offering the best visual acuity. Five topographical characteristics were collected via the Pentacam: mean keratometry (Km), maximum keratometry (Kmax), distance from corneal center to Kmax (dKmax), Belin/Ambrosio Display (BAD_D), and index of surface variance (ISV). RESULTS: Forty-six eyes were included in the dial group (64.8%), 23 eyes in the cylinder group (32.4%), and only 2 eyes in the slit group (2.8%); thus, we only compared dial and cylinder groups. The main analysis retrieved a significant probability to choose dial technic for BAD_D (p = 0.024); when BAD_D is > 9.71 (ROC threshold), the positive predictive value (PPV) = 89.5%, and for ISV, p = 0.012; when ISV is > 77, PPV = 89.1%. The sub-analysis of patients with different visual acuities between cylinder and dial confirmed these results with slightly different thresholds: the probability to choose dial technic was for BAD_D, p = 0.03; when BAD_D is > 7.55, PPV = 90%, and for ISV, p = 0.0084; when ISV is > 71, PPV = 88.5%. CONCLUSION: Refraction method is linked to topographic indices ISV and BAD_D. A BAD_D > 7.55 indicates the dial method. In addition to keratoconus screening and diagnosis, this study suggests a new application of the topographer to select a suitable refraction method for eyeglass prescription. TRIAL REGISTRATION: Study registered on the ClinicalTrials.gov database under n°: NCT04174209.

Rastreamento visual, photoscreening e dispensação de óculos com a tecnologia ready to ClipTM / Visual acuity screening, photoscreening and dispensing of glasses with ready to Clip™ technology

Resumo Introdução: Os rastreamentos visuais realizados nas escolas são, às vezes, a única oportunidade de deteção dos erros de refração não corrigidos (ERN) causadores de baixa visual, prejuízo na aquisição do conhecimento, evasão e repetência escolar, habilidades motoras pobres, dificuldade na interação social e baixa autoestima nos escolares. Objetivos: Comparar a detecção de ERN em escolares do ensino fundamental por meio de rastreamento visual (medida da AV com a tabela de Snellen) e por photoscreener; avaliar a acurácia do SpotTM Vision Screener (Welch Allyn) como autorefrator comparando suas medidas de refração com as do autorrefrator Topcon KR 8000 (Japão) e levantar a proporção de óculos com a tecnologia ready to Clip™ que foram dispensados no momento da avaliação dos escolares. Métodos: Duzentos e noventa e sete escolares foram submetidos à rastreamento visual (ponto de corte: AV monocular ≤ 0,7 e/ou diferença duas linhas de Snellen entre os olhos), photoscreening (ponto de corte: hipermetropia ≥3,00D, miopia ≥0,75D e astigmatismo > 1D) e à mensuração do erro de refração sob cicloplegia com o photoscreener e o autorrefrator. Somente os dados de refração do olho direito foram analisados. Os achados foram convertidos em vetores de magnitude para análise. Resultados: Os valores de sensibilidade e especificidade do método de rastreamento visual foram 67,2% e 63,5% e do photoscreening, foram 76,1% e 79,1%. A diferença da refração do SVS com o autorrefrator foi de +0,154 DE com -0,170 DC no eixo de 6 graus para o olho direito de cada paciente. Conclusões: Na população avaliada o método de rastreamento refrativo por photoscreener foi mais efetivo que o do rastreamento visual. A comparação dos resultados da refração sob cicloplegia com o autorrefrator validou o uso do photoscreener como um método de refração acurado para a mensuração de erros refrativos em escolares. A maioria dos escolares receberam os óculos com a tecnologia ready to Clip™ no momento da prescrição.

Abstract Background: The visual screening performed in schools is sometimes the only opportunity to detect uncorrected refraction errors (URE) causing low visual impairments, prejudice in the acquisition of knowledge, dropout and school repetition, poor motor skills, difficulty in social interaction and low self-esteem in schoolchildren. Objectives: To compare the detection of URE in elementary school children by visual screening (measurement of the AV with the Snellen table) and photoscreening; to evaluate the accuracy of the SpotTM Vision Screener (Welch Allyn) as an autorefractor by comparing its refraction measurements with those of the autorefractor Topcon KR 800 (Japan) and to verify the proportion of glasses with ready to ClipTM technology dispensed at the time of the students' evaluation. Methods: Two hundred ninety-seven students were submitted to visual screening (cutoff point: AV monocular ≤ 0.7 and/or difference two Snellen lines between the eyes), photoscreening (cutoff point: hypermetropia ≥ 3, 00D, myopia ≥ 0, 75D and astigmatism > 1D) and the measurement of the refraction error under cycloplegia with the photoscreener and autorefractor. Only the refraction data of the right eye were analyzed. The findings were converted into vectors of magnitude for analysis. Results: The sensitivity and specificity values of the visual screening method were 67.2% and 63.5% and photo screening were 76.1% and 79.1%. The mean difference between refraction by SVS and autorefractor was of + 0.154 SD combined with -0.170 DC in the 6-degree axis for the right eye of each patient. Conclusions: In the population evaluated the method of refractive screening by photoscreener was more effective than the visual screening. The comparison of the results of refraction under cycloplegia with the autorefractor validated the use of photoscreener as an accurate refraction method for the measurement of refractive errors in schoolchildren. The majority of the students received their glasses with ready to Clip™ technology at the time of prescription.

Comparison of keratometric measurements between color light-emitting diode topography and Scheimpflug camera.

BACKGROUND: To determine the agreement of measurements between color light-emitting diode corneal topography (Cassini) and Scheimpflug camera keratometry (Pentacam HR). METHODS: The current retrospective study investigated 117 right eyes of 117 healthy patients before cataract surgery from June 2017 to July 2017. Steep K, flat K, mean K, astigmatism, and axis for both anterior and posterior corneal surface were measured using the two devices. The measured values were converted into J vectors such as J0 and J45. The mean difference for those measurement values were compared between the two instruments, and the agreement was evaluated using the Bland-Altman plot I. RESULTS: There were statistically significant differences in mean K (44.21D [43.34 to 45.34] and 44.30D [43.30 to 45.10] by Cassini and Pentacam [P = 0.004]) and astigmatism (0.90D [0.58 to 1.30] and 0.70D [0.40 to 1.30] by Cassini and Pentacam [P = 0.002]) on the anterior corneal surface and flat K (- 6.21D [- 6.39 to - 6.07] and - 6.30D [- 6.5 to - 6.10] by Cassini and Pentacam [P < 0.001]), mean K (- 6.39D [- 6.54 to - 6.25] and - 6.40D [- 6.60 to - 6.30] by Cassini and Pentacam [P = 0.019]), and astigmatism (0.33D [0.22 to 0.47] and 0.30D [0.15 to 0.40] by Cassini and Pentacam [P = 0.002]) on the posterior corneal surface. The mean difference (= Cassini - Pentacam) with 95% limit of agreement for mean K and astigmatism of the anterior corneal surface were 0.082D (- 0.60 to 0.76) and 0.11D (- 0.73 to 0.95) for measurements obtained by the two instruments, respectively. Regarding keratometric values from the posterior corneal surface, the mean differences for flat K, mean K, and astigmatism were - 0.081D (- 0.42 to 0.26), - 0.030D (- 0.32 to 0.26), and 0.067D (- 0.33 to 0.46), respectively. Intraclass correlation coefficients for steep K, flat K, mean K, and vector J0 were higher than 0.9 in the anterior cornea. Positive correlation in steep K, flat K, mean K, astigmatism, and J0 was found between two devices in both anterior and posterior cornea (P < 0.001). CONCLUSIONS: Corneal refractive power and astigmatism tend to be higher when measured using Cassini than Pentacam HR in both anterior and posterior cornea. The two different devices might not be used interchangeably. TRIAL REGISTRATION: Retrospectively registered. Registration number: KC17RESI0439 .

The components of adult astigmatism and their age-related changes.

PURPOSE: To study the corneal and internal astigmatism and the age-related changes underlying the known refractive shift with-the-rule (WTR) towards against-the-rule (ATR) astigmatism. METHODS: Refractive and corneal biometry data were collected for a total of 1195 healthy Caucasian subjects, recruited by ophthalmological centres across Europe. After conversion of refractive and corneal surface astigmatism to power vectors J0 and J45 , the total corneal and internal astigmatism were calculated. RESULTS: Both refractive power vectors had leptokurtic distributions with a narrow peak at zero, and a broader, secondary distribution at its base, corresponding to eyes without balanced components. This may be fitted with a bigaussian function (J0 : r² = 0.87; J45 : r² = 0.98). Statistically significant changes in these distributions are seen with age: for refractive J0 the narrow peak shortens progressively, while the broad peak shifts positive from to negative values, corresponding to increased astigmatism and a shift from with-the-rule towards against-the-rule. For J45 the narrow peak shortens with age as well, while the broad peak flattens. These changes in refractive J0 result from statistically significant negative shifts in both the corneal and internal components with age (Kruskal-Wallis, p < 0.05). CONCLUSION: In young participants corneal and internal astigmatism partially cancel each other out. This balance between both is gradually lost after age 50, leading to larger amounts of refractive astigmatism, as well as a reorientation of the axis. Given the small amplitude of these changes, they are unlikely to have repercussions for long term stability toric cataract or refractive surgery outcomes.

Refractive error magnitude and variability: Relation to age.

PURPOSE: To investigate mean ocular refraction (MOR) and astigmatism, over the human age range and compare severity of refractive error to earlier studies from clinical populations having large age ranges. METHODS: For this descriptive study patient age, refractive error and history of surgery affecting refraction were abstracted from the Waterloo Eye Study database (WatES). Average MOR, standard deviation of MOR and astigmatism were assessed in relation to age. Refractive distributions for developmental age groups were determined. MOR standard deviation relative to average MOR was evaluated. Data from earlier clinically based studies with similar age ranges were compared to WatES. RESULTS: Right eye refractive errors were available for 5933 patients with no history of surgery affecting refraction. Average MOR varied with age. Children <1 yr of age were the most hyperopic (+1.79D) and the highest magnitude of myopia was found at 27yrs (-2.86D). MOR distributions were leptokurtic, and negatively skewed. The mode varied with age group. MOR variability increased with increasing myopia. Average astigmatism increased gradually to age 60 after which it increased at a faster rate. By 85+ years it was 1.25D. J0 power vector became increasingly negative with age. J45 power vector values remained close to zero but variability increased at approximately 70 years. In relation to comparable earlier studies, WatES data were most myopic. CONCLUSIONS: Mean ocular refraction and refractive error distribution vary with age. The highest magnitude of myopia is found in young adults. Similar to prevalence, the severity of myopia also appears to have increased since 1931.

Comparison of biometric predictability and final refraction expected in phacoemulsification surgery with and without trabeculectomy / Comparação da previsibilidade biométrica e refração final esperada em cirurgia de facoemulsificação com e sem trabeculectomia

Abstract Objective: The main purpose of this article is to compare the predictability of biometric results and final refractive outcomes expected in patients undergoing cataract surgery through phacoemulsification with and without associated trabeculectomy. Methods: Cataract patients who have undergone phacoemulsification surgery alone (control group) or associated with trabeculectomy (study group) screened. All surgeries were performed following standard protocol. For enrollment, biometrics calculated by IOL Master (Carl Zeiss Meditec, Inc.) biometry, refraction and intraocular pressure (IOP) before and after surgery were required. Data was compared between groups in addition to the correlation between variation of IOP and final refraction. Results: Thirty eyes per group were enrolled. Only prior IOP (p <0.001), IOP post-surgery (p = 0.01) and the difference in IOP (p <0.001) were statistically significant. Axial length, IOL diopter used, expected spherical refraction by biometrics and astigmatism pre- and post-surgery were similar in both groups (p=0.1; 0.4; 0.4; 0.5 and 0.3, respectively). Spherical predictability by biometrics within 0.25 diopters was noted in both the control group (range 0.06 ± 0.45) and study group (range 0.25 ± 0.97, p = 0.3). There was no statistical significance between groups for the difference between final cylinder and corneal astigmatism (p = 0.9), and the difference between axis of refractive and corneal astigmatism (p = 0.7). Conclusion: The biometric predictability in phacoemulsification surgery and the expected final refraction are significant, andare not modified by trabeculectomy in the combined surgeries.

Resumo Objetivo: Comparar a previsibilidade dos resultados refracionais e da biometria em pacientes submetidos à cirurgia de catarata por facoemulsificação com e sem trabeculectomia (Trec) associada. Métodos: Pacientes com catarata submetidos à cirurgia de facoemulsificação isolada (grupo controle) ou associada a Trec (catarata + glaucoma, grupo estudo) foram consecutivamente selecionados. Todas as cirurgias foram feitas seguindo protocolo padrão. Para inclusão, era necessário apresentar biometria calculada pelo biômetro IOL Master (Carl Zeiss, Meditec, Inc), refração e pressão intraocular (Pio) pré e pós-operatórios. Os dados foram comparados entre os grupos, além da correlação entre a variação da Pio e a refração final. Resultados: Foram incluídos 30 olhos por grupo. Na comparação, apenas a Pio prévia (p<0,001), Pio pós cirurgia (p=0,01) e a diferença de Pio pré-pós cirurgia (3,8 ± 4,4mmHg vs. 15,5 ± 9,3mmHg, grupos controle e estudo, respectivamente, p<0,001) foram estatisticamente significativos. Diâmetro axial, dioptria da Lio utilizada, dioptria esperada pela biometria e astigmatismo prévio e pós- cirurgia foram estatisticamente semelhantes entre os grupos (p=0,1; 0,4; 0,4; 0,5 e 0.3, respectivamente). Notou-se previsibilidade esférica pela biometria dentro de 0,25 dioptrias, tanto no grupo controle (variação de 0,06 ± 0,45), quanto no grupo estudo (variação de 0,25 ± 0,97, p=0,3). Não houve significância estatística entre os grupos para a diferença entre o cilindro final e o astigmatismo corneano em dioptrias (p=0,9), e diferença entre o eixo do astigmatismo refracional e corneano (p=0,7). Conclusão: A previsibilidade biométrica e a refração na cirurgia de facoemulsificação aferida pelo biômetro IOL Master é significativa, e não sãoalteradas na cirurgia combinada com trabeculectomia.

Accommodation stimulus and response determinations with autorefractors.

PURPOSE: To develop equations for accommodation stimulus and accommodation response with autorefractors when the accommodation stimulus is produced by combinations of object distances and lenses placed in front of eyes, and to give worked examples using these equations. METHODS: Simple ray tracing was used to determine stimulus and response equations, taking into account the reference positions for targets, for refraction, and for autorefractor readings. RESULTS: Several examples applying equations are provided. Features of these examples include evaluating approximate calculations that have been used previously, demonstrating which equations should be used in different circumstances, how to substitute numbers into equations, how to deal with discrepancies between subjective and objective refraction, and how to deal with astigmatism. Problems associated with measuring accommodation response by placing lenses in front of the eye are discussed. CONCLUSIONS: Accurate equations for accommodation stimulus and accommodation response for a range of accommodation stimuli in different setups have been developed.

Research progress on refractive status after early treatment for severe retinopathy of prematurity / 眼科新进展

Early treatment including cryotherapy,laser therapy and intravitreal anti-VEGF agent injection for retinopathy of prematurity with threshold retinopathy of prematurity (ROP),prethreshold ROP (type I) or aggressive posterior ROP (AP-ROP) have certain effect on ocular structure,development and refractive status.And this paper will give a review on the latest advance in refractive status after the early treatment for severe ROP.

Research progress on refractive status after early treatment for severe retinopathy of prematurity / 眼科新进展

Early treatment including cryotherapy,laser therapy and intravitreal anti-VEGF agent injection for retinopathy of prematurity with threshold retinopathy of prematurity (ROP),prethreshold ROP (type I) or aggressive posterior ROP (AP-ROP) have certain effect on ocular structure,development and refractive status.And this paper will give a review on the latest advance in refractive status after the early treatment for severe ROP.