Brian Levy

Factors related to the progression of myopia in Singaporean children

Purpose To examine the possible factors related to the progression of myopia in Singapore children. Methods One hundred fifty-three Singapore children aged 6 to 12 years were recruited to participate in a concurrent cohort study of the risk factors for the progression of myopia. Socioeconomic status, outdoor activity, and near-work activity were documented in a face-to-face clinic interview. The changes in cycloplegic subjective refraction and autorefraction were ascertained with the use of a Nidek ARK 900 over a 2-year period. Results The average rate of progression of myopia as measured by subjective refraction was −0.59 D per year (95% confidence interval −0.52, −0.66). Younger children and children who were more myopic at the beginning (refractive error worse than −2.0 D) of the study had higher myopia progression rates. Conclusions Myopia progression was faster for younger children and for children who had more severe myopia at baseline. Socioeconomic status and near-work activity were not related to myopia progression.

Familial clustering and myopia progression in Singapore school children

BACKGROUND. Familial factors may be related to the progression of myopia in children. A cohort study was conducted to determine the relationship between familial factors and myopia progression in children. METHODS. From a larger clinical trial (n = 311), 153 Singapore children aged 6–12 years were recruited to participate in a cohort study of the risk factors for myopia progression. An in-person interview was conducted whereby information on the history of myopia in first-degree relatives was obtained. Other information collected included housing type, parental education and income. Cycloplegic refractive error as measured by subjective refraction and autorefraction were ascertained every six months. The average length of follow-up was 28 months. RESULTS. The adjusted mean rate of progression of myopia was -0.60 (95% confidence interval -0.66, -0.55) diopters per year. The average rate of progression of myopia for children with a parental history of myopia was -0.63 (95% confidence interval -0.69, -0.56) diopters per year compared to -0.42 (95% confidence interval -0.57, -0.27) diopters per year for children whose parents were not myopic. The different measures of family history of myopia were related to rate of change in refractive error and refractive error in the final visit. There was no association between close work and myopia progression. CONCLUSIONS. A positive family history is related to the progression of myopia and final refractive error in Singapore children, thus supporting evidence that hereditary factors may play an important role in myopia progression.

Calcium deposits on glyceryl methyl methacrylate and hydroxyethyl methacrylate contact lenses

Five patients wore a hydroxyethyl methacrylate (HEMA) lens on one eye and a glyceryl methyl methylcrylate (GMA) lens on the other eye. The eye with the GMA lens remained comfortable longer than the other eye. The GMA lens is less likely to acquire calcium deposits and continues to be wearable longer than the HEMA lens.

PROSPECTIVE TRIAL OF DAILY AND EXTENDED WEAR DISPOSABLE CONTACT LENSES

Purpose The current study prospectively evaluates the response to daily and extended wear of disposable lenses with each patient acting as his/her own control. This paradigm allowed for elimination of individual variation as a confounding factor, as well as determining whether an intrinsic factor, other than lens wear, predisposed patients to complications. Methods One hundred thirty-four patients were randomly assigned to contralateral daily wear (DW) or extended wear (EW) with Acuvue lenses for 1 year. All lenses were disposed of on a weekly basis. Bilateral bacteriology of lids, conjunctivae, lenses, and fingers was carried out on those patients presenting with complications. Results The results after 1 year indicate a higher incidence of complications in the EW eye (peripheral infiltrative keratopathy, 12%; corneal striae, 3%). No significant clinical complications occurred in the DW eye. Microbiological cultures did not reveal any significant difference between those eyes with keratopathy and those of controls. The most common pathogen was Staphyloccocus epidermidis. No gram-negative organisms grew from any of the culture sites. Conclusions The results of this study indicate that extended wearing schedules, and not the lens entity, predispose the patient to a higher risk of keratopathy with disposable contact lenses. No microbiological association with the adverse events could be determined, and no intrinsic patient factor could be demonstrated that would predict the likelihood of complications.

Incidence of oculo-visual anomalies in an adult population of mentally retarded persons.

ABSTRACT Clinical examination of 298 mentally retarded adults revealed a higher frequency of ocular anomalies of all types than is typical of a group of nonretarded subjects of the same age. It also became apparent that fewer of the mentally retarded had had appropriate optometric care than an equivalent nonretarded sample. The evidence indicates that correcting their ocular problems helps the retarded, yet these subjects receive less than average care.

Rigid gas-permeable lenses for extended wear--a 1-year clinical evaluation.

ABSTRACT A 1‐year evaluation of the feasibility of the use of gas‐permeable rigid lenses for extended wear was carried out, using two different materials. Forty subjects were entered into the study. Fifteen were fitted with the Polycon II lens and another 15 with the Boston IV lens. These two groups wore the lenses on a weekly basis for the duration of the study. Two other groups, the controls, were fitted with the same types of lenses as the experimental groups, but wore the lenses on a daily basis. All lenses were made to the Syntex specifications for the Polycon lens and the groups were comparable with regard to age, sex, refractive error, corneal astigmatism, and any pre‐existing ocular pathology. All subjects carried out the same care regimen for their lenses and were examined after 24 h, 1 week, 1 month, 3 months, 6 months, and 1 year. Examinations performed at the follow‐up visits were to determine any clinically observable effects of lens wear in each patient in all groups. The results of the study suggest that the extended wear of gaspermeable rigid materials is a viable option. However, the results also indicate that extended wear is not without problems, and these need to be studied more fully before the use of gas‐permeable rigid lenses for extended wear can be recommended.

Hypotony and Corneal Edema Secondary to Patching in Normal Eyes

Over the past decade investigators have used patching when studying corneal response to eye lid closure. In these studies, corneal edema was thought to be secondary to hypoxia, and the results were used to predict corneal response to contact lens wear. None of these studies have measured or controlled the intraocular pressure (IOP) during eye patching. Reports in the literature indicate that hypotonous and hypertensive events may induce corneal edema. In order to evaluate the IOP and corresponding corneal changes, measurements were made on subjects with patched eyes. Thirty subjects were unilaterally patched and randomized into tight and light patch groups to maintain complete lid closure for 4 h. Measurements of IOP and corneal thickness (CT) were made at baseline and at hourly intervals. The contralateral eye served as the control for each subject. Our results indicate a significant decrease in IOP and a corresponding increase in CT in the tight patched group as compared to the light patch group, and baseline controls. These results suggest that the corneal edema which results from patching of the eye may be due to hypotony, or a combination of factors affecting corneal function, rather than hypoxia.

Acute ptosis secondary to contact lens wear.

Ocular ptosis secondary to the wearing of rigid contact lenses has been reported. Generally this ptosis is not of the classical variety, and appears to be an edematous or inflammatory response of the lid to the presence of the lens. We report a case of acute ptosis secondary to rigid lens wear in a patient who had undergone cataract surgery. The patient had been a contact lens wearer before surgery, and developed the relative ptosis postsurgically in the nonoperated eye. The ptosis resolved without any form of intervention other than ceasing to wear the contact lens. We feel that in cases where rigid lens wear is discontinued unilaterally for any reason, and a relative ptosis is noted, it should be given time to resolve before any therapeutic regimen is considered.

Complications of rigid gas permeable lenses for extended wear.

A retrospective study of 174 patients wearing rigid gas permeable lenses for a period of 2 years was carried out to determine the success rate and types of complications which typically occur. The results indicate that these types of lenses are a viable modality for extended wear, as the majority of signs which may lead to serious complications can be detected relatively early. When these signs were detected the patients were switched to daily wear and most were able to wear these lenses uneventfully. However, the results also indicate that unexpected problems can occur, and thus frequent follow-up is essential in these patients in order to avoid the potentially sight-threatening problems which have come to be associated with extended wearing of contact lenses.

Clinical study of Bendazac Lysine for in vivo contact lens cleaning

Bendazac Lysine (BZL), a nonsteroidal anti-inflammatory drug (NSAID), prevents denaturation of proteins secondary to chemical and physical activity. The major protein deposited on soft contact lenses is lysozyme, derived from the preocular tear film. We evaluated the effectiveness of eye drops formulated with BZL for in vivo prevention of proteinaceous deposits on contact lenses and found them to be useful in inhibiting protein deposition during a 6-month clinical trial.