Reproducibility study of posterior subcapsular opacities on the NEI retroillumination image analysis system.

We developed a semi-automated retroillumination image analysis system which combines speed, ease of operation and interactive analysis. The system measures cataract area and integral of cataract density (ID). For system reproducibility evaluation, 20 eyes with posterior subcapsular opacities were captured twice by two photographers. Variability was estimated under a random effects analysis of variance model. Measurement errors for area and for ID were each small contributors to total variability (the sum of variability between study eyes plus measurement error), being 0.4% and 0.1% respectively. The largest contributor to area measurement error was image analysis variability (97%). For ID measurement error, the variability in images (44%) and in image analysis (46%) were major contributors. The reproducibility is comparable to previously described retroillumination analysis systems. This easy to use system may therefore be useful in clinical research studies including possible clinical trials of anti-cataract drugs.

Senile cataract progression studies using the Lens Opacities Classification System II.

PURPOSE: To determine cataract progression rates at 6-mo intervals as evaluated using the Lens Opacities Classification System II (LOCS II). METHODS: Idiopathic age-related cataracts in both eyes of 50 cataract patients and 17 normal control subjects were graded. The lenses were reexamined at 6 and 12 mo (+/- 2 mo) from baseline to determine rates of change. Progression or regression in patients or control subjects was considered to have occurred at the 6-mo examination if a one or more step change in the LOCS II grading was noted in at least one eye at 6 mo and maintained at the 12-mo visit. RESULTS: Six months from baseline, 38% of patients' conditions worsened in the nuclear area, 34% of patients' conditions worsened in the cortical region, and 8% of patients' conditions worsened in the posterior subcapsular region. Regression rates were 4% in each region. The percentages of patients progressing in the nuclear and cortical regions were significantly greater than the corresponding regression rates (P < .001). Greater progression was noted in the nuclear (P = .06) and posterior subcapsular (P < .01) regions in patients with early opacities (LOCS + 1/+2) as compared to patients with no opacities initially in the same lenticular areas. CONCLUSION: This study suggests that the LOCS II is capable of detecting changes in lens opacities in a relatively short period of time among persons with early to moderate opacities.