RESUMEN
PURPOSE: To examine relationships between mesopic visual sensitivity measurements on microperimetry and macular inner and outer retinal layer (IRL and ORL) thicknesses in healthy younger, middle-aged and older subjects. METHODS: In total, 154 healthy adults were divided into three age groups each with similar mean sensitivity. Regional retinal sensitivity (determined by mesopic fundus-controlled microperimetry) and IRL (ganglion cell-related layer) and ORL thicknesses were measured in the five subfields: central fovea (1 mm diameter) and the quadrants temporal, nasal, superior and inferior of a parafoveal ring of outer diameter 3 mm and inner diameter 1 mm. Relationships between regional sensitivity and corresponding IRL and ORL thicknesses were assessed through a univariate and multivariate linear regression model. RESULTS: Visual sensitivity means for each subfield differed across age groups (all p < 0.001). In each parafoveal ring quadrant, mean IRL thickness was reduced in the older eyes compared to the other groups (all p < 0.0001). In the inferior region, worse sensitivity was correlated with greater IRL thickness (p = 0.0207) in the middle-aged group and with a thicker ORL (p < 0.0001) and thinner IRL (p = 0.0003) in the older eyes (R2 = 0.51). The slopes of regression lines relating sensitivity to IRL thickness and age group (p = 0.0027) or to ORL thickness and age group (p = 0.0020) differed significantly. CONCLUSIONS: The relationship observed between mesopic visual sensitivity and retinal layer thickness varied with age. A worse sensitivity was related to a thicker macular IRL layer in middle-aged eyes and to a thicker ORL and thinner IRL in older eyes.
RESUMEN
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.
