Contact lens induced papillary conjunctivitis with silicone hydrogel lenses.

PURPOSE: To describe the refitting of a soft lens wearer into a silicone hydrogel lens due to neovascularization. This change, in turn, caused contact lens induced papillary conjunctivitis (CLPC) and a further refitting was necessary. METHODS: The patient was refit into a high Dk surface treated silicone hydrogel with a high modulus value. A second refitting was undertaken into a lower Dk silicone hydrogel contact lens with a lower modulus value which had no surface treatment but incorporated an internal wetting agent. RESULTS: A high Dk/t lens was used to resolve existing neovascularization and chronic hyperaemia. Subsequently, CLPC response occurred, possibly due to a combination of factors, resulting in irritation of the palpebral conjunctiva. This resulted in temporary lens discontinuation. A second silicone hydrogel lens was fit, along with the use of a non-preserved care system, which led to improvement and eventual resolution of the condition. CONCLUSION: High Dk silicone hydrogel lenses have shown excellent efficacy in resolving hypoxic complications such as neovascularization and hyperaemia. However, attention needs to be paid to their potential effect on the upper tarsal plate. More than one silicone hydrogel lens may be needed to help resolve these issues.

Clinical characterization of spherical post-lens debris associated with lotrafilcon high-Dk silicone lenses.

PURPOSE: Experience with high Dk silicone hydrogel lenses has revealed post-lens debris, which is characterized by the appearance of spherical, translucent particles referred to as "mucin balls." The objectives of this analysis were to characterize the presence of mucin balls, determine whether any ocular characteristic predicts the development of mucin ball debris, and determine whether there is any association between mucin balls and the ocular response to contact lens wear. METHODS: Ninety-two subjects wore lotrafilcon A lenses on an extended wear basis for up to 30 nights and were followed for 6 months. Mucin balls were graded on a 0 to 4 scale at three visits. Subjective ratings and biomicroscopic appearance were recorded at all visits. RESULTS: Mucin balls were observed in 70% of subjects at one or more visits, and 29% of subjects at all three visits. There was no change in the mean grade of mucin balls over time. Mucin balls were graded > 1 in 20% of eyes, > 2 in 6% of eyes, and > 3 in 2% of eyes. Subjects who exhibited mucin balls at each clinical visit had significantly steeper keratometry readings along the flatter meridian (44.3 D) than those who never exhibited mucin balls (42.9 D, P < 0.0001). The percentage of subjects who "never" use lubricating drops was higher in the subjects with mucin balls (P = 0.0014). No association was found between mucin ball observation and biomicroscopic appearance, inflammatory responses, or subjective responses. CONCLUSIONS: The presence of mucin balls does not appear to be detrimental to contact lens wear. Eyes with steeper corneal curvature were significantly more likely to present with mucin ball debris, indicating they may be a function of lens fit. Clinical factors that may be modified in order to manage the more severe presentation of mucin balls are the use of lubricating drops and the number of nights extended wear schedule.

The genetic aspects of adult-onset glaucoma: a perspective from the Greater Toronto area.

BACKGROUND: The myocilin gene is the first glaucoma gene to be associated with primary open-angle glaucoma (POAG). The hereditary subset of POAG and the role of the myocilin gene in our population are not clearly defined. Identification of cases of hereditary glaucoma and a better appreciation of the role of the myocilin gene may allow earlier diagnosis of the disease and optimize management of those at risk for glaucoma. METHODS: Patients were recruited from university glaucoma practices in the Greater Toronto area from 1996 to 1998. Pedigree analysis and DNA banking were performed for each participant. Mutational analysis of the myocilin gene by means of single-strand conformation polymorphism analysis and direct sequencing was completed for 140 probands with POAG of diverse ethnic background. RESULTS: A total of 103 patients (55.7%) had a family history of glaucoma. Disease-causing mutations of the myocilin gene were observed in 7 (5.0%) of the 140 probands, which accounted for 6.5% (5/77) of the familial cases. Most mutations were associated with familial disease, which implies a 50% risk of transmission of a high-risk factor for glaucoma. INTERPRETATION: The hereditary subset of POAG is significant, and heritable glaucoma should always be suspected. In spite of the diversity of the ethnic background of our subjects, the observed prevalence of myocilin gene mutations was comparable to that previously reported, and such mutations do not appear to spare any ethnic group.

Interobserver agreement of Heidelberg retina tomograph parameters.

PURPOSE: To measure the interobserver agreement of Heidelberg Retina Tomograph (HRT; Heidelberg Engineering, Heidelberg, Germany) parameters as a result of different observers' contour line placement. METHODS: The optic nerve heads of 50 patients with glaucoma were imaged with the HRT. Five observers traced each disc margin with a contour line. Each observer was masked to the contour line tracings of the other observers, and there was no formal discussion as to where to place the contour line. The following stereometric parameters were calculated for each image for each observer: disc area, mean height of contour, cup shape, rim volume using the standard reference plane from software version 1.11, rim volume using a reference plane of 320 microns below the retinal plane, and volume above curved surface. Agreement between the five observers was tested for each parameter using intraclass correlation coefficients (ICCs). RESULTS: Interobserver agreement between the five observers was substantial for both rim volumes (ICC = 0.73) and for disc area (ICC = 0.67). Agreement was almost perfect for mean height of contour (ICC = 0.94), cup shape (ICC = 0.92), and volume above curved surface (ICC = 0.83). CONCLUSION: The interobserver agreement for the HRT parameters was substantial to almost perfect, indicating that the HRT results as defined by the five observers were interchangeable.

Analysis of myocilin mutations in 1703 glaucoma patients from five different populations.

A glaucoma locus, GLC1A, was identified previously on chromosome 1q. A gene within this locus (encoding the protein myocilin) subsequently was shown to harbor mutations in 2-4% of primary open angle glaucoma patients. A total of 1703 patients was screened from five different populations representing three racial groups. There were 1284 patients from primarily Caucasian populations in Iowa (727), Australia (390) and Canada (167). A group of 312 African American patients was from New York City and 107 Asian patients from Japan. Overall, 61 different myocilin sequence variations were identified. Of the 61 variations, 21 were judged to be probable disease-causing mutations. The number of probands found to harbor such mutations in each population was: Iowa 31/727 (4.3%), African Americans from New York City 8/312 (2.6%), Japan 3/107 (2.8%), Canada 5/167 (3.0%), Australia 11/390 (2.8%) and overall 58/1703 (3. 4%). Overall, 16 (76%) of 21 mutations were found in only one population. The most common mutation observed, Gln368Stop, was found in 27/1703 (1.6%) glaucoma probands and was found at least once in all groups except the Japanese. Studies of genetic markers flanking the myocilin gene suggest that most cases of the Gln368Stop mutations are descended from a common founder. Although the specific mutations found in each of the five populations were different, the overall frequency of myocilin mutations was similar ( approximately 2-4%) in all populations, suggesting that the increased rate of glaucoma in African Americans is not due to a higher prevalence of myocilin mutations.

Laser scanning tomography of the optic nerve head in ocular hypertension and glaucoma.

BACKGROUND: This study evaluated the ability of laser scanning tomography to distinguish between normal and glaucomatous optic nerve heads, and between glaucomatous subjects with and without field loss. METHODS: 57 subjects were classified into three diagnostic groups: subjects with elevated intraocular pressure, normal optic nerve heads, and normal visual fields (n = 10); subjects with glaucomatous optic neuropathy and normal visual fields (n = 30); and subjects with glaucomatous optic neuropathy and repeatable visual field abnormality (n = 17). Three 10 degrees image series were acquired on each subject using the Heidelberg retina tomograph (HRT). From the 14 HRT stereometric variables, three were selected a priori for evaluation: (1) volume above reference (neuroretinal rim volume), (2) third moment in contour (cup shape), and (3) height variation contour (variation in relative nerve fibre layer height at the disc margin). Data were analysed using analysis of covariance, with age as the covariate. RESULTS: Volume above reference, third moment in contour, and mean height contour were significantly different between each of the three diagnostic groups (p < 0.001). Height variation contour showed no significant difference among the three diagnostic groups (p = 0.906). CONCLUSIONS: The HRT variables measuring rim volume, cup shape, and mean nerve fibre layer height distinguished between (1) subjects with elevated intraocular pressures and normal nerve heads, and glaucomatous optic nerve heads, and (2) glaucomatous optic nerve heads with and without repeatable visual field abnormality. This study did not directly assess the ability of the HRT to identify patients at risk of developing glaucoma. It is hypothesised that the greatest potential benefit of laser scanning tomography will be in the documentation of change within an individual over time.