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A. K. Kiser, L. Yang, D. A. Kiser, G. Dagnelie; Photopsias : A Common Phenomenon Reported by Retinitis Pigmentosa (RP) Patients. Invest. Ophthalmol. Vis. Sci. 2008;49(13):3152. doi: https://doi.org/.
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It has been hypothesized that photopsias in RP are manifestations of spontaneous activity in microneuromas triggered through inner plexiform layer connections, possibly due to ganglion cell and axon loss in the degenerating retina. There is surprisingly little systematic information published in the literature on subjective descriptions of photopsias in RP. We developed a questionnaire to learn more about this phenomenon.
We inquired about the prevalence, appearance, natural history, possible associations and impact of photopsias. A survey posted on an anonymous internet forum was initially completed by 50 RP patients with any level of vision.
46 respondents reported experiencing photopsias, of those: 46% were already noticing photopsias when they were first diagnosed with RP. 62% experienced photopsias daily. Photopsias were most often described as: arcs or semi-circles (58%), crescents (44%), sparklers or fireworks (40%), swirls (40%), or spots (38%).The majority (74%) experienced them for only a few seconds and were statistically significantly more likely to experience them in areas where they still have vision (p=0.04). Overall, there were no differences in terms of location in central vs. peripheral field. However, those with great difficulty or needing assistance when alone in unfamiliar areas were statistically significantly more likely to report photopsias only in central vision (p=0.003).52% reported increased photopsia frequency over time. 60% indicated that photopsias interfere with vision. Those who can read very small print or cannot read without magnification (either early or late in disease progression) were statistically significantly more likely to report interference with vision (p=0.04) or trying to ignore photopsias (p=0.03).Increased photopsias occurred most often with: stress (50%), fatigue (46%), bright light (44%), exercise (40%), fast head movement (34%), or absence of light (34%). Fatigue was statistically significantly more likely reported by those with photopsias in less than half the visual field versus the whole field (p=0.04).Data from additional respondents will be presented.
The characteristics of photopsias appear to vary across RP patients. Many experienced them daily, reported interference with vision, and not just in the later stages of RP. Therefore clinicians and researchers should be aware of their occurrence. Photopsias may be linked in important ways to the processes occurring during retinal implant stimulation, and their characterization may be helpful for the future development of prosthetic vision.
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