| Vision tests are more variable in legally blind retinitis pigmentosa (RP) patients than in normally-sighted individuals. RP patients have indicated that increased stress is associated with reductions in vision; however, this relationship or other patient-related factors related to vision variability have not been previously formally elucidated. A preliminary survey suggested that photopsias (spontaneous phosphenes or flashes) in RP are increased by bright light, fatigue or stress, and their location may be related to the severity of vision loss, potentially interfering with vision.;Visual acuity (VA) and contrast sensitivity (CS) and visual field (VF) variabilities (SD) were determined over multiple tests (mean of 16) by 37 RP subjects at home on a personal computer (PC) twice a week, and correlated with psychosocial questionnaires administered at each PC-test session. We examined whether measured and reported worse-than-usual vision and photopsias during the PC-tests were related to level of vision, psychosocial factors, light exposure, or general health reported at each PC-test session. We correlated 32 RP subjects' survey responses regarding photopsias' characteristics with clinical measures of VA, Pelli-Robson CS and Goldmann VF.;Increased VA and VF variability was predicted largely by increased RP severity indicated by reduced mean vision measures (R2=0.80 and 0.44, respectively). Greater VF variability occurred in subjects with reduced VF who had greater than minimal depressive symptoms (8.3%;95%CI:1.8, 14.9%;p=0.015). Reports of worse vision than usual and >20% VF reductions were statistically significantly more common in those with advanced vision loss, roughly 2 times greater when decreased general health was reported, and more likely at test sessions when perceived stress was increased. Photopsias were statistically significantly more likely at PC-based vision test sessions when perceived stress was greater (OR:1.16;95%CI:1.01,1.33;p=0.048) or positive affect was lower (OR:0.83;95%CI:0.73,0.94;p=0.004). In later RP stages, photopsias tend to be located more centrally, over larger regions, in areas with vision, and/or occur with increased frequency, potentially obstructing vision at times.;These associations between RP severity and increased vision variability and photopsias, as well as the role of negative psychosocial factors, are important to consider during clinical exams and trials, especially when making judgments regarding whether true changes in vision have occurred. |
