Visual Discrimination Increase by Yellow Filters in Retinitis Pigmentosa

PURPOSE: The objective of this study was to evaluate, by halometry and under low illumination conditions, the effects of short-wavelength light absorbance filters on visual discrimination capacity in retinitis pigmentosa patients. METHODS: This was an observational, prospective, analytic, and transversal study on 109 eyes of 57 retinitis pigmentosa patients with visual acuity better than 1.25 logMAR. Visual disturbance index (VDI) was determined using the software Halo 1.0, with and without the interposition of filters which absorb (totally or partially) short-wavelength light between 380 and 500 nm. RESULTS: A statistically significant reduction in the VDI values determined using filters which absorb short-wavelength light was observed (p < 0.0001). The established VDIs in patients with VA logMAR <0.4 were 0.30 ± 0.05 (95% CI, 0.26–0.36) for the lens alone, 0.20 ± 0.04 (95% CI, 0.16–0.24) with the filter that completely absorbs wavelengths shorter than 450 nm, and 0.24 ± 0.04 (95% CI, 0.20–0.28) with the filter that partially absorbs wavelengths shorter than 450 nm, which implies a 20 to 33% visual discrimination capacity increase. In addition, a decrease of VDI in at least one eye was observed in more than 90% of patients when using a filter. CONCLUSIONS: Short-wavelength light absorbance filters increase visual discrimination capacity under low illumination conditions in retinitis pigmentosa patients. Use of such filters constitutes a suitable method to improve visual quality related to intraocular light visual disturbances under low illumination conditions in this group of patients. © 2016 American Academy of Optometry

Contrast sensitivity evaluation with filter contact lenses in patients with retinitis pigmentosa: a pilot study

Purpose: the aim of this pilot study was to test whether retinitis pigmentosa patients would benefit from filter contact lenses as an effective optical aid against glare and photophobia. Methods: fifteen subjects with retinitis pigmentosa were enrolled in this study. All of them were evaluated with filter soft contact lenses (MaxSight), filter glasses (CPF 527) and without filters (control). All patients were assessed for the three aid conditions by means of best corrected visual acuity (BCVA), contrast sensitivity (without glare and with central and peripheral glare)(CSV-1000) and a specific subjective questionnaire about quality of vision. Results: BCVA was slightly better with filters than without filter but the differences were not statistically significant. Contrast sensitivity without glare improved significantly with the contact lenses (p<0.05). The central glare had significant differences for the frequencies of 3 cpd and 18 cpd between the contact lens filter and the control group (p=0.021 and p=0.044, respectively). For the peripheral glare contrast sensitivity improved with contact lens versus control group for highest frequencies, 12 and 18 cpd (p<0.001 and p=0.045, respectively). According to the questionnaire the contact lens filter gave them more visual comfort than the glasses filter under the scenarios of indoors glare, outdoors activities and indoors comfort. Conclusion: the filter contact lenses seem to be a good option to improve the quality of vision of patients with retinitis pigmentosa.

Retinal Macroglial Responses in Health and Disease

Due to their permanent and close proximity to neurons, glial cells perform essential tasks for the normal physiology of the retina. Astrocytes andM¨uller cells (retinal macroglia) provide physical support to neurons and supplement them with several metabolites and growth factors.Macroglia are involved in maintaining the homeostasis of extracellular ions and neurotransmitters, are essential for information processing in neural circuits, participate in retinal glucose metabolism and in removing metabolic waste products, regulate local blood flow, induce the blood-retinal barrier (BRB), play fundamental roles in local immune response, and protect neurons from oxidative damage. In response to polyetiological insults, glia cells react with a process called reactive gliosis, seeking to maintain retinal homeostasis. When malfunctioning, macroglial cells can become primary pathogenic elements. A reactive gliosis has been described in different retinal pathologies, including age-related macular degeneration (AMD), diabetes, glaucoma, retinal detachment, or retinitis pigmentosa. A better understanding of the dual, neuroprotective, or cytotoxic effect of macroglial involvement in retinal pathologies would help in treating the physiopathology of these diseases.The extensive participation of the macroglia in retinal diseases points to these cells as innovative targets for new drug therapies.