International contact lens clinic (New York, N.Y.)最新文献

Deep stromal neovascularization (DNV) is a very rare complication of contact lens (CL) wear. The aim of this study was to describe the clinical features and management of CL-related DNV in a series of patients. We retrospectively studied nine patients who presented with CL-related DNV over a 16-year period in a single hospital-based specialty CL practice. The clinical features, progression, and management of DNV in this series are discussed. Seven of nine patients were found to have keratoconus as a primary diagnosis. DNV remained stable or regressed in six patients following improvement in CL design and management. One patient required corneal transplantation, and two failed to return for sufficient follow-up. Improvement in CL design and material to optimize mechanical fit and enhance corneal oxygenation may stabilize DNV associated with CL wear.

Tear breakup time (TBUT) is the most commonly used test for tear stability. The tear stability measurement is particularly important in the diagnosis of dry eye and in determining when contact lens wear is not to be recommended. TBUT values for normal Saudi population with consideration of gender and age have not been reported. TBUT measurements were done on 220 normal subjects, 140 males and 80 females, aged 5 to 75 years. Eighty-seven percent of the subjects had TBUT values >10 seconds. Results showed the mean TBUT was 18.0 ± 7.0 seconds. The value was higher than those reported for Asian countries but lower than those of Western countries. There was no significant difference between males and females, but TBUT values decreased with increasing age.

The contrast sensitivity function (CSF) of soft contact lens wearers and the CSF of those without corrective lenses were measured. Subjects without corrective lenses achieved higher contrast sensitivity (CS) scores than did those wearing soft contact lenses, whether tinted or clear. Subjects wearing clear soft contact lenses had slightly higher CSF at most spatial frequencies than did those wearing tinted soft contact lenses, but the difference was not significant. The implications of this research on the factors influencing CS function in contact lens wearers are discussed.

Central corneal thickness of both eyes of 18 normal subjects was measured in a study comparing a Haag-Streit optical pachometer and an ultrasonic pachometer (Teknar Ophthasonic, preset velocity 1630 m/sec). All subjects were awake for 3 hours before measurements to reduce swelling of the cornea from overnight eye closure. Reliability was assessed by a three-way analysis of variance between repeated measurements for the optical and ultrasonic pachometers. The former revealed a systematic right–left difference, the left cornea being significantly thicker. The correlation coefficient indicates that the link between the two variables is 0.92 and 0.88 for right and left eyes, respectively. It is concluded that, for clinical purposes, optical and ultrasonic pachometry techniques are comparable. The effect of the daily and extended-wear contact lenses on central corneal thickness also was studied. The degree of change (morning vs evening) in corneal thickness of the polymacon group was lower and decreased with the wear, whereas in the etafilcon A group the change was greater and almost constant with the time of wear.

Clinicians commonly comment that few keratoconic patients >60 years of age are followed. We hypothesize that this observation occurs because keratoconics present less frequently for contact lens care with age. Charts of 106 keratoconic patients followed in one contact lens practice for at least 24 months during a 33-month period were reviewed retrospectively. The number of professional evaluations and ages of keratoconic patients during their second year of care were considered and compared to a nonkeratoconic control group. Keratoconic and nonkeratoconics both show normal age distributions that decline after 60 years of age. Keratoconics were found to be slightly older and presented for significantly more professional care compared to non-keratoconic patients in the second year of care. Fewer keratoconics and nonkeratoconics present for contact lens care after 60 years of age. Keratoconics present for contact lens care longer than do nonkeratoconics.

Corneo-scleral rigid gas permeable lenses represent a new category of contact lens. Incorporating an overall diameter of approximately 14 to 15 mm, the corneo-scleral lens is larger than a corneal lens yet smaller than a scleral lens. A 39-year-old man was referred to our office for a contact lens fitting following penetrating keratoplasty of the left eye for advanced keratoconus. The patient was successully prescribed a corneo-scleral contact lens for the left eye.