Novel vision tests: data analysis from a RP Lutein trial

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DESCRIPTION (provided by applicant): Retinitis pigmentosa (RP) affects over 100,000 individuals in the US, and causes nightblindness, gradual loss of peripheral vision, and eventually total vision loss. Surgical and medical efforts have not been able to slow down photoreceptor degeneration in RP. We are currently completing a NCCAM-sponsored placebo-controlled crossover pilot study with a nutrition supplement (lutein), which has previous been shown to have a positive effect on visual acuity and central visual field area in RP patients. ETDRS visual acuity-measured in the laboratory once per 6 weeks-is the primary outcome measure of the lutein study; 10 secondary outcome measures were collected during laboratory visits, including several not originally envisaged, and 13 more during weekly self-administered automated tests on each participant's home PC. Study participants included 43 RP patients taking lutein, and an additional 10 participants-some with RP, some normally-sighted-collecting data to allow validity assessment of the PC-based tests. This has provided us with a unique and very large collection of outcome data, and a preliminary analysis has shown that the PC-based have excellent reproducibility. The limited scope of the lutein pilot study could not cover a detailed analysis of this large data collection. We propose to validate PC-based outcome measures by analyzing their stability and mutual consistency, and by comparing them to lab-based outcome measures, for 20-23 RP patients on placebo supplements during the first 24 weeks of the trial and for subjects not taking lutein. In addition, we will use the lab-based primary and secondary outcome measures following lutein supplementation as calibration measures for any changes observed in the PC-based test outcomes. Detailed study of these data will not only be significant in assessing the potential effects and time course of lutein on vision in RP , but also in validating a collection of well-calibrated, automated home tests that may provide a cheap, effective, and frequent method for monitoring vision between clinic visits in future clinical trials.