• Vision test reliability across multiple test administrations in relation to psychological and external factors [ Time Frame: 2-3 months ] [ Designated as safety issue: No ]
  

An initial study visit for enrollment will take place at the Johns Hopkins Wilmer Eye Institute's Lions Vision Center. We will enroll 50 RP subjects with vision better than hand motions or bare light perception, who are able to complete PC-based vision tests. Written informed consent for study participation will be obtained at the first study visit.

At home PC-based vision tests will be performed bi-weekly, for 2 months (i.e. 16 measures) to capture the full range of variability. Binocular visual acuity (VA), contrast sensitivity (CS) and visual field (VF) tests will be self-administered by the RP subjects, and will take ~10 minutes. Three brief questionnaires will be administered by PC after each vision test session: 1) Perceived Stress Scale (PSS); 2) Stanford Sleepiness Scale (SSS); and 3) Positive and Negative Affect Schedules (PANAS). Lab-based vision tests will take place at the time of enrollment, and will include: (1) distance best-corrected VA with the ETDRS charts, (2) Pelli-Robson letter CS, (3) Goldmann VF with V/4e and III/4e isopters, and (4) Humphrey 10-2 or 30-2 VF FastPac program. The vision tests and questionnaires are a part of routine clinical care.

After enrollment, we will obtain information about psychological factors by administering the following questionnaires by phone on one occasion:

Pittsburgh Sleep Quality Index, Emotional Stability, Beck Depression Inventory, the Self-Motivation Inventory, and the Life Experiences Survey.

Questionnaires assessing health-related quality of life (SF-36) and mental status (MMSE) will also be administered. We will use a phone version of the MMSE only for screening. Other variables that may be of importance to the study will be assessed through a complete patient medical, ocular and social history, including questions such as duration of visual impairment, occupation, marital status, etc. The questionnaires are often used in research settings and sometimes in clinical settings. Many patients appreciate the opportunity to provide feedback since these areas are not always addressed as part of routine, clinical care. Focus group meetings, facilitated by Dr. George and Lori Edwards, will help us begin to understand factors are perceived to influence fluctuations in vision.

Subjects will participate in study procedures over the course of a 3 month period. This includes an enrollment visit at our center with lab-based vision tests, and then approximately 2 months PC-based vision testing.