Abstract
Abstract: :
Purpose: this study evaluates hyperbaric oxygen (HBO) exposure on rescuing retinal photoreceptors independently from the gene cause of RP. Methods Two age and sex matced randomized groups of RP; first treated with HBO (44pts mean age 35,02±5,6),, the second as control (44pts. mean age 35,5±14,3). We performed a complete ophthalmological examination, and therapeutic scheduling of HBO as previously reported, Statistical analysis was performed with Kaplan-Mayer’s "Life Table". We described the difference of visual acuity loss, visual field patterns decay and ERG amplitude. Negative event were considered when visual acuity Mean sensitivity and ERG amplitude were 20% less than the baseline. Results: after 12 year of follow up it resulted that 53,33% of patients treated with HBO preserved 80% of the initial visual acuity, while the same percentage of residual visual acuity in patients that did not underwent HBO was 40% (fig. 4). (c2=3,22; p<0,1). Visual field did not change in 68,4% of HBO group and 42,1% of control group. Moreover In this group considering target I4 at the beginning of the follow up time patients in the worst conditions in our analysis, were respectively 47% of HBO group and 76,5% of control group. Discussion Several studies documented that retinal photoreceptor cells in normal conditions have an increased oxidative metabolism and are strictly conditioned by oxygen partial pressure in peripheral tissues. Some authors have hypothesised a role for hyperbaric oxygen in therapy of RP. Moreover several studies seem to indicate that oxygen retinal availability may be a critical point in the development of tapetoretinal degenerations, in fact according Stone’s studies this condition of transient hyperoxia may rescue retinal photoreceptors and the effect causes an increase in ERG max. amplitude that lasts for several months. Increase of oxygen availability, induced by HBO, could complete metabolic requests. Significant improvement in VA and visual field progression, obtained in present study, seems to confirm the hypothesis, specially related to the evident VA and visual field loss in RP-control group. In our opinion different inherited errors in protein structure can cause rod malfunction reduced by HBO causing photoreceptors recovery. Therefore, it is possible to conclude that in our hypothesis HBO delivery determines a rescue of retinal photoreceptors contributing in stabilization of clinical conditions, thus confirming our and other Authors data as previously reported in the literature.
Keywords: apoptosis/cell death • clinical (human) or epidemiologic studies: tre • retinal degenerations: hereditary