Michel Millodot

The possible effect of undercorrection on myopic progression in children

Background:  Undercorrection has recently been found to enhance the rate of progression of myopia. This result was thought to be controversial as it contrasted with expectations based on animal studies, as well as the results found wearing progressive addition lenses. The aim of the present study was to again determine the effect of undercorrection on the progression of myopia in a random population of children who are known to be very susceptible to myopia.

Prevalence and associated factors of keratoconus in Jerusalem: a cross-sectional study.

Purpose: To determine the prevalence and associated factors for keratoconus in a college student population sample in Jerusalem. Methods: Volunteers participated in this cross-sectional study. Videokeratography was performed on both eyes of each subject who also completed an anonymous questionnaire. Keratoconus was defined by cone apex ≥ 50D, inferior-superior dioptric difference ≥ 3.5 diopters, as well as positive results from the software indices KISA, KCI and KSI. The association between independent predictors and keratoconus was analyzed using multivariate logistic regression analysis. Results: Of a total of 987 volunteers, 981 (mean age 24.4) were included. The prevalence of keratoconus among all subjects was 2.34% (95% confidence interval [CI] 1.4–3.3). It was significantly higher in men (4.91%, CI 2.6–7.3) than women (1.07%, CI 0.3–1.9) but not between Israeli Arabs (3.0%, CI 0.6–5.4) and Israeli Jews (2.2%, CI 1.2–3.3). Keratoconus was significantly associated with positive family history of the disease (Odds Ratio [OR] 17.1, CI 5.0–57.8, P < 0.001), male gender (OR 5.4, CI 2.1–14.3, P = 0.001) and atopy (OR 3.0, CI 1.2–7.6, P = 0.02), but not with eye rubbing. Conclusions: The prevalence of keratoconus in Jerusalem was found to be much higher than that seen in other parts of the world, except India. This may be related to a combination of genetic and environmental factors. Positive family history, male gender and atopy were shown to be significant predictors. The results of this study signal a need for public health outreach and intervention for keratoconus.

VARIATION OF ASTIGMATISM WITH ACCOMMODATION AND ITS RELATIONSHIP WITH DARK FOCUS

Abstract— The refraction of 122 eyes was measured for five distances of fixation with an objective Canon Auto Refractor. The cylindrical component was found to vary, but by a small amount. We found no evidence of a deliberate reduction in astigmatism with accommodation, in accord with other studies. The axis was also found to vary by at least 5° in about half of the subjects tested, which is also in good accord with other investigations. The dark focus of 31 eyes was not found to correlate with a minimum astigmatic distance, since this only occurred in II out of the 31 eyes. For these 11 eyes, the correlation of dark focus and the dioptric distance where astigmatism was minimum was equal to + 0.54. It implied that for those eyes (about one‐third of all types) there was a tendency to yield the best optical quality at the dark focus.

Characteristics of 244 patients with keratoconus seen in an optometric contact lens practice

The purpose of this study was to describe the characteristics of keratoconic patients seen in a specialised contact lens practice from a general population with a high prevalence of the disease.

Peripheral visual acuity and refractive error: Evidence for “two visual systems”?

Experiments conducted in two independent laboratories indicate that the correction of refractive errors does not improve peripheral visual acuity. This finding contrasts with previous results for motion detection and other visual functions in the periphery. The “two visual systems” hypothesis provides a heuristic means of interpreting this apparent discrepancy.

Current applications and efficacy of scleral contact lenses — a retrospective study

Purpose: To evaluate the indications and effi cacy of high gas permeable scleral contact lenses (GP-SCL).

Risk factors for keratoconus in Israel: a case–control study

Keratoconus (KC) is a progressive corneal thinning disorder with an uncertain aetiology. Environmental and genetic factors, including consanguinity, eye rubbing and possibly sun exposure, play a role in the aetiology of KC. Here we test for risk factors for KC in an Israeli population with particular emphasis on sun exposure.

Full correction and Undercorrection of Myopia Evaluation Trial: design and baseline data of a randomized, controlled, double-blind trial

To determine the difference in the rate of myopic progression between children wearing single vision lenses with undercorrection of +0.50 D and children whose myopia is fully corrected, and to explore the factors that may influence the process.

Efficacy of Chinese Eye Exercises on Reducing Accommodative Lag in School-Aged Children: A Randomized Controlled Trial

Purpose To evaluate the efficacy of Chinese eye exercises on reducing accommodative lag in children by a randomized, double-blinded controlled trial. Methods A total of 190 children aged 10 to 14 years with emmetropia to moderate myopia were included. They were randomly allocated to three groups: standard Chinese eye exercises group (trained for eye exercises by doctors of traditional Chinese medicine); sham point eye exercises group (instructed to massage on non-acupoints); and eyes closed group (asked to close their eyes without massage). Primary outcome was change in accommodative lag immediately after intervention. Secondary outcomes included changes in corrected near and distant visual acuity, and visual discomfort score. Results Children in the standard Chinese eye exercises group had significantly greater alleviation of accommodative lag (-0.10D) than those in sham point eye exercises group (-0.03D) and eyes closed group (0.07D) (P = 0.04). The proportion of children with alleviation of accommodative lag was significantly higher in the standard Chinese eye exercises group (54.0%) than in the sham point eye exercises group (32.8%) and the eyes closed group (34.9%) (P = 0.03). No significant differences were found in secondary outcomes. Conclusion Chinese eye exercises as performed daily in primary and middle schools in China have statistically but probably clinically insignificant effect in reducing accommodative lag of school-aged children in the short-term. Considering the higher amounts of near work load of Chinese children, the efficacy of eye exercises may be insufficient in preventing myopia progression in the long-term. Trial Registration ClinicalTrials.gov NCT01756287

Chinese Eye Exercises and Myopia Development in School Age Children: A Nested Case-control Study.

Chinese eye exercises have been implemented in China as an intervention for controlling children’s myopia for over 50 years. This nested case-control study investigated Chinese eye exercises and their association with myopia development in junior middle school children. Outcome measures were the onset and progression of myopia over a two-year period. Cases were defined as 1. Myopia onset (cycloplegic spherical equivalent ≤ −0.5 diopter in non-myopic children). 2. Myopia progression (myopia shift of ≥1.0 diopter in those who were myopic at baseline). Two independent investigators assessed the quality of Chinese eye exercises performance at the end of the follow-up period. Of 260 children at baseline (mean age was 12.7 ± 0.5 years), 201 were eligible for this study. There was no association between eye exercises and the risk of myopia-onset (OR = 0.73, 95%CI: 0.24–2.21), nor myopia progression (OR = 0.79, 95%CI: 0.41–1.53). The group who performed high quality exercises had a slightly lower myopia progression of 0.15 D than the children who did not perform the exercise over a period of 2 years. However, the limited sample size, low dosage and performance quality of Chinese eye exercises in children did not result in statistical significance and require further studies.