Intraocular light scatter in patients with choroideremia

Objective: This study aimed to evaluate the extent of intraocular light scatter in patients with choroideremia. Design: Prospective case-control study. Participants: Twelve male patients with choroideremia who had predominantly minimal or no posterior subcapsular cataract (PSG) lens opacities and visual acuities of 20/40 or better and 30 age-similar control subjects with normal vision and no lens opacities were studied. Intervention: Intraocular light scatter was measured using a van den Berg Straylightmeter. Main Outcome Measures: Visual acuities, letter contrast sensitivities, Goldmann visual fields using a II4e target, and straylight parameters were obtained for each patient. Lenses were assessed by slit-lamp biomicroscopy to determine whether there were PSC opacities. The degree of retinal pigment epithelial and choroidal degenerative changes was evaluated from color fundus photographs. Results: Three of the patients with choroideremia who had clinically apparent PSC lens opacities showed an increase in intraocular light scatter. More notable was the fact that seven of the remaining nine patients who did not have any clinically apparent changes in the lens also had a considerable increase in the intraocular light scatter as compared to the control subjects. The relative elevations of the log straylight parameters of the patients with choroideremia, as compared to age-similar control subjects, were correlated significantly with their log visual field areas (r = -0.69, P < 0.05). Conclusions: Intraocular light scatter may be increased in patients with choroideremia, even in the absence of clinically observable PSC opacities. It is hypothesized that the increase in light scatter may be caused by changes in the posterior subcapsular region of the lens before the formation of frank PSC cataracts. The increased straylight could, at least in part, account for the disability glare reported by these patients.