The progression of myopia in school age children: data from the Columbia Medical Plan.

The purpose of this study was to characterize the clinical course of myopia in a selected pediatric population. The computerized records of a health maintenance organization provided longitudinal data on 501 children aged 5 to 15 years. We examined the influence of age at diagnosis, gender, race, and initial refraction on progression of myopia. Mean follow-up was 34 months, with 75% of children having follow-up longer than 16 months. The mean rate of myopic progression was greater for children whose myopia was diagnosed at a younger age (5-7 years, -0.56 diopters/year versus 11-15 years, -0.28 diopters/year; p < 0.0001). Children with more than one diopter of myopia at first diagnosis progressed faster than children with less than or equal to one diopter of myopia (mean rate -0.48 diopter/year versus -0.41 diopter/year; p = 0.05). Cumulative event rate curves suggest a gender effect in the prepuberty years of 8 to 10, with myopia progressing faster in girls than boys (p = 0.003). Progression of myopia did not differ between white and non-white children. More rapidly progression of myopia is associated with younger age at initial diagnosis and greater severity of initial myopic refraction.

A longitudinal study of cortical cataracts using retroillumination photographs.

The National Eye Institute (NEI) computer planimetry system has been shown to have good reproducibility in assessing the size of cortical cataracts from retroilluminatin photographs. In this study, we determined the usefulness of this system in monitoring cortical cataract changes over time. Using the Neitz Kawara retroillumination camera, retroillumination photographs of cortical cataracts in 81 eyes were obtained every six months for an average of 31 months. As previously described, the cortical cataract outlines were traced in a masked fashion onto transparent plastic overlays, and the tracings then digitized into a Macintosh Quadra computer using a computer scanner. Cortical cataract area was then determined using a specially developed software program. For each eye, the rate of cortical area change was determined by the slope of the regression line fitted to the follow-up measurements. Cataract progression was classified to be significant if the slope exceeded a critical value. Of the 81 eyes, 24 (30%) had significant cataract progression, while 57 (70%) did not progress. This study presents data on progression of the area of cortical cataracts and suggests the usefulness of the NEI computer planimetry system for monitoring such changes from retroillumination photographs. The slope-based test can also play a useful part in longitudinal studies with irregular time intervals and variable number of visits.

Potential vision tests in patients with cataracts.

PURPOSE: To determine the limits of usefulness of the potential acuity meter (PAM) and the laser interferometer (LI) in determining potential visual acuity in various severities and types of cataracts. METHODS: The study included 48 patients (67 eyes) who were undergoing cataract surgery and who had PAM and LI tests. The 67 eyes were grouped into (1) eyes with cataracts only (45 eyes) and (2) eyes with cataracts and other ocular diseases (22 eyes). Group 1 eyes were subdivided into two groups according to their Lens Opacities Classification System II (LOCS II) grading: 1a eyes (moderate cataracts) had an LOCS II grade of nuclear opalescence (NO) < 4 and cortical opacity (C) < 5 and posterior sub-capsularcataract (P) < 4, and group 1b eyes (severe cataracts) had an LOCS II grade of NO = 4 or C = 5 or P = 4. The accuracy of the PAM and LI was estimated separately for each group. RESULTS: For moderate cataracts, the accuracy of the PAM was 100% and of the LI was 92%. For severe cataracts, the accuracy of the PAM was 52% and of the LI was 79%. Both instruments tended to underestimate visual outcome more in eyes with posterior subcapsular cataracts. For eyes with other ocular diseases, the LI tends to overestimate the probable visual outcome more than the PAM, especially in patients with poor retinal function. CONCLUSIONS: Several factors such as preoperative visual acuity of 20/200 or worse, the type and severity of the cataract, and coexisting retinal disorders may affect the accuracy of the PAM and LI tests, and these should be considered when interpreting predicted vision, especially in preoperative counseling of patients.

Longitudinal study of posterior subcapsular opacities using the National Eye Institute computer planimetry system.

BACKGROUND: The National Eye Institute (NEI) computer planimetry system has proved to be helpful in cross sectional studies by providing clinically useful area measurements of posterior subcapsular cataracts (PSC) and other opacities from retroillumination photographs. In this study, we evaluated the worth of this system in detecting PSC area changes over time. METHODS: Using the Neitz-Kawara camera, retroillumination photographs of the PSCs of 51 eyes were obtained every 6 months for an average of 25 months. The PSCs were outlined in a masked fashion on plastic overlays. Their tracings were then digitised on to a computer using a scanner. PSC area was determined using a special software program. For each eye, the rate of PSC area change was estimated by the slope of the regression line fitted to the follow up measurements. Cataract progression was classified as significant if the slope exceeded a critical value. RESULTS: These showed that 14 of the 51 eyes had PSC progression, while 37 did not change. CONCLUSION: This study suggests the system is useful for longitudinally monitoring PSC area changes from retroillumination photographs. This system would serve in natural history studies of PSCs and in clinical trials of anticataract drugs. The slope based test can play a part in longitudinal studies with irregular time intervals and variable number of visits.

Study of nuclear cataract progression using the National Eye Institute Scheimpflug system.

AIMS: A study was conducted to determine the capability of the recently developed National Eye Institute (NEI) Scheimpflug cataract imaging system in detecting changes in the nuclear region of the lens over a 1 year period. METHODS: Twenty five eyes with pure nuclear cataracts with mean nuclear densities < or = 0.30 optical density units (ODU) as well as 30 normal control eyes were each examined at baseline and 12 months later. Computerised densitometry using the NEI Scheimpflug cataract imaging system was performed. Clinical grading of the lenses was also done using the Lens Opacities Classification System II (LOCS II). For densitometry, a change of plus or minus 0.023 ODU (the 99% range) in mean density in the nuclear area was considered a progression or regression at 1 year. RESULTS: Using the Scheimpflug densitometry, 14 of the 25 cataractous eyes showed significant progression at 1 year. In the normal control group, only three of the 30 eyes showed significant progression. In contrast, using the LOCS II clinical grading, only two of the 25 cataractous eyes showed a one step increase, two of the 30 controls progressed at 1 year, and none regressed. There was no significant difference in visual acuity. CONCLUSION: This study suggests the value of the NEI Scheimpflug cataract imaging system in detecting nuclear change within 1 year. However, clinically significant changes may require longer follow up periods. These data will be useful in planning future longitudinal studies of nuclear cataracts, such as for clinical trials of anticataract drugs.

Comparison of linear, multilinear and mask microdensitometric analyses of Scheimpflug images of the lens nucleus.

We wanted to determine the agreement among three methods currently used to measure the average density of the nucleus from a Scheimpflug video image of the lens, namely, the multilinear, linear and mask techniques. Using the NEI Scheimpflug Cataract Imaging System, video images of the lens were obtained from 49 eyes of 31 consecutive patients with predominantly nuclear opacities of varying severities. For each image, 3 separate determinations of the average nuclear density [in optical density units (odu)] were obtained by one analyst sequentially applying each of the three methods. Repeat measurements were obtained by the same analyst one week apart to evaluate reproducibility (using 95% error range), of each of the methods. Pairwise comparisons of the 3 methods were also done. Only the error due to outlining of the nucleus was assessed. Reproducibility of each method was excellent. The 95% error ranges were +/- 0.015 odu for the linear, +/- 0.013 odu for the multilinear, and +/- 0.017 odu for the mask methods. Very strong linear relationships were observed between the linear and multilinear methods (R2 = 0.99), between the linear and mask methods (R2 = 0.97), and between the multilinear and mask methods (R2 = 0.98). Simple linear regressions calibrating these three methods against each other would facilitate comparison of density measurements using any of these methods for analysis of Scheimpflug images of the lens nucleus.

Reproducibility of the NEI Scheimpflug Cataract Imaging System.

PURPOSE: The NEI Scheimpflug Cataract Imaging System was developed to allow for easy, accurate and reproducible image analysis of nuclear cataracts. This study was undertaken to determine the reproducibility of densitometric measurements of the lens nucleus using this modified system. METHODS: Replicate Zeiss Scheimpflug images of the lenses in 143 eyes were obtained by one photographer. Normal and cataractous lenses (without central cortical or anterior subcapsular opacities) were sampled. Images were stored after testing for adequacy using immediate exposure checking. Densitometry of the nuclear region was then performed for each image. The interval within which 99% of the differences between repeat measurements may be expected to lie was used as a measure of reproducibility (99% range). RESULTS: A 99% range of +/- 0.023 optical density units (odu) was obtained for nuclear densities < 0.30 odu (125 eyes). For lenses with nuclear densities > or = 0.30 odu (18 eyes), the 99% range was +/- 0.14 times the first measurement. CONCLUSION: This study shows the excellent reproducibility of this Scheimpflug imaging system in the nuclear region and demonstrates its usefulness in studies on nuclear cataracts, particularly for natural history studies and clinical trials of anti-cataract drugs.

Relative letter and position difficulty on visual acuity charts from the Early Treatment Diabetic Retinopathy Study.

Ten Sloan letters were used in the visual acuity charts developed for use in the Early Treatment Diabetic Retinopathy Study. We used the data from the 3,710 Early Treatment Diabetic Retinopathy Study subjects to investigate the relative difficulty of the ten Sloan letters and to evaluate whether the position of a letter on a line affected its relative difficulty. In general, our findings were consistent with those of the previous study. The four letters with curved contours (C, O, S, and D) were more difficult to discern at threshold than the six letters (Z, N, H, V, R, and K) composed of straight lines. Our data demonstrate that under these test conditions, letters at the end of a line are more likely to be read incorrectly than letters at the beginning of the line. This finding indicates that these data are probably not useful for evaluating possible crowding phenomena.

Lens opacities in neurofibromatosis 2: further significant correlations.

This prospective study of 96 individuals from 29 families with neurofibromatosis 2, 49 of whom were affected, confirms in an extended series the previously reported association between posterior subcapsular/capsular cataract and neurofibromatosis 2. Posterior subcapsular/capsular cataracts were found in 36 (80%) of the 45 affected individuals (four individuals were excluded from statistical analyses). In addition, the association of peripheral cortical lens opacities with neurofibromatosis 2 was found to be statistically significant. Seventeen of the patients with neurofibromatosis 2 (37.8%) had peripheral cortical cataracts in comparison with none of the unaffected family members (p < 0.0001). In three patients peripheral cortical opacities were present despite the absence of posterior subcapsular/capsular cataracts. These findings support the inclusion of cortical cataracts of early onset, in addition to posterior subcapsular/capsular cataracts, in the diagnostic criteria of neurofibromatosis 2.

A masked, randomized, dose-response study between cyclosporine A and G in the treatment of sight-threatening uveitis of noninfectious origin.

Thirty-two patients with sight-threatening uveitis and a decrease in visual acuity requiring systemic therapy were randomly assigned to either cyclosporine A or G in a dose-escalation study. Groups received from 2.5 mg/kg of body weight/day to 10 mg/kg of body weight/day of either drug along with low-dose prednisone. More patients taking cyclosporine G had improved visual acuity and a decrease in macular edema, which occurred more rapidly than in the other group, even at the lower doses tested. No difference in renal function was noted between groups at any doses tested. Four patients receiving cyclosporine G had hepatic alterations, but only one required cessation of the drug. The study indicates the potential usefulness of cyclosporine G, particularly at lower doses (4 mg/kg of body weight/day), which could lower the potential for serious renal complications.

HLA associations and ancestry in Vogt-Koyanagi-Harada disease and sympathetic ophthalmia.

A strong association with HLA antigens DR4, DRw53, and Bw54 has previously been reported among Japanese patients with Vogt-Koyanagi-Harada disease (VKH) and sympathetic ophthalmia (SO). In the United States, no firm association between HLA-A or -B loci and VKH has been found previously; testing for HLA-DR loci has not been performed to date. The authors performed HLA typing of 23 American patients with VKH and 8 patients with SO. When VKH patients were compared with racially matched controls without disease and patients with other types of uveitis, strong associations with HLA-DR4 and HLA-DRw53 were found. The strongest associations observed in this sample were with HLA-DQw3, an antigen which is in positive linkage disequilibrium with DR4, and with the HLA-DR4/DQw3 haplotype. The small number of patients with SO precluded statistical analysis; however, similar HLA associations were noted. The patients also were questioned regarding their ancestry. The anecdotal association of VKH with American Indian ancestry was confirmed. It appears that the ethnoracial association may be explained by HLA type. One possible explanation for identical HLA associations in two diseases with different precipitating events yet similar ocular manifestations is development of an altered immune response to exogenous microbial antigen with subsequent autoimmunity. Further definition of the genetic susceptibility to VKH and SO may help define the pathophysiology of both diseases and allow the prediction of which patients are at increased risk for SO.

Computerized cataract detection and classification.

156 eyes of patients and normal volunteers were classified at the slit lamp into the following pure groups: normal (n = 50), nuclear (n = 39), cortical (n = 33) and PSC (n = 34). The eyes were photographed with the Topcon SL-45 Scheimpflug camera and the images scanned and processed to obtain one dimensional profiles through a 40 x 440 micron axial window. Of the 156 profiles, 90 were used as reference samples and were processed to obtain average profiles. The remaining 66 "unknown" profiles and each of the reference profiles, were classified into the four groups based on their distance from the average profiles in Euclidean space. The system was found to be very sensitive (98%) in detecting the presence of cataracts and specific (100%) in identifying normal, i.e. cataract negative lenses. In classifying pure cataracts into the various classes 98% of answers were correct.

The association of posterior capsular lens opacities with bilateral acoustic neuromas in patients with neurofibromatosis type 2.

This study of 47 patients from 11 families with neurofibromatosis type 2 (NF 2) confirms our previously reported association between posterior capsular cataract and NF 2. A highly significant statistical association was found between the presence of posterior capsular lens opacities and the presence of NF 2 as determined by magnetic resonance imaging or pathologic diagnosis. This association was not present for other types of lens opacities that could be the result of age-related or nonspecific changes. When considering the diagnosis of NF 2, this finding now makes it essential to use a careful dilated biomicroscopic examination of the lens to evaluate known, suspected, or at-risk individuals for this potentially early associated manifestation.