Intraocular Light Scatter in Patients with Retinitis Pigmentosa

Abstract

We evaluated the level of intraocular light scatter in a group of patients with retinitis pigmentosa (RP) who had minimal or no lens opacities, since such patients not infrequently complain of photoaversion. Intraocular light scatter was measured in 20 patients with RP who were < 60 years of age and who had no more than a trace of posterior subcapsular (PSC) lens opacity by slit-lamp evaluation. Measurements of intraocular straylight were made using a van den Berg Straylightmeter. Results from the patients with RP were compared with those of a control group of 30 subjects with normal vision whose ages were similar to those of the patients with RP. Seventeen of the 20 patients with RP had straylight levels that were above the range of age-similar normal control subjects. In some patients, the straylight parameter was increased by a factor of 2.5 above the normal mean for the patient's age and by as much as four to five times the normal mean for 20-yr-old subjects. There was a statistically significant correlation (r = -0.73, P < 0.01) between the patients' log relative elevation in the straylight parameter and their log visual field areas. Our findings indicate that patients with RP can have increased levels of intraocular light scatter despite minimal or no clinically observable PSC lens opacities. The increased intraocular straylight, which is likely due at least in part to subclinical abnormalities in lens morphology, can accentuate the visual disability of patients with RP in the presence of glare sources.

Retinitis pigmentosa: visual function and multidisciplinary management

“…Disability glare occurs when the retinal image loses its contrast through physical factors, such as reflection from shiny pages, inappropriately placed light sources or intraocular light scatter. 108,109 Patients with RP can experience both types of glare. 110 People with RP can eliminate discomfort glare by using dark filters with side shields.…”

Understanding disability glare: light scatter and retinal illuminance as predictors of sensitivity to contrast

“…There are also a number of other individual differences -initial thresholds, iris pigmentation [50] and susceptibility to discomfort glare [51], to name just a few -that could impact upon visual performance in the presence of glare. Furthermore, it would be of great interest to investigate the extent to which the relationship is affected by pathological conditions that are associated with increased scatter, such as cataracts [18,52], corneal dystrophy [37], keratoconus [53] and retinitis pigmentosa [54], as well as the potential effects of contact lens wear [55,56] and refractive surgery [57][58][59]. Expanding the sample upon which the contrast threshold curve is based has the potential to improve the accuracy of the predictions, possibly by tailoring the formulae to specific age groups.…”

Clinical Characterization and Frequency of Observation of Hereditary Retinal Diseases: Multicentric Study in Panama in 2012-2013

“…Glare was expected, associated with affectation of the macula, or subclinical subcapsular changes in the lens, even without evidence of cataract [41,62].…”

“…The presence of hemeralopia or photophobia in 34.5% of the patients can be attributed to a greater dispersion of intraocular light, even in the absence of observable cataract [41], or to cystic macular edema, described in 18% of RP patients [42].…”