Direct comparison of retinal structure and function in retinitis pigmentosa by co-registering microperimetry and optical coherence tomography

Abstract

PurposeTo evaluate the retinal structure-function relationships in the macula of retinitis pigmentosa (RP) patients by comparing microperimetry-3 (MP-3) images with co-registered optical coherence tomography (OCT) images.MethodsThirty patients with typical RP were recruited from our hospital. The maculae of patients were examined with MP-3 and OCT. The retinal sensitivity was measured by MP-3 at 40 testing points arranged concentrically in a 16° diameter of the central retina, and we divided the 40 points into four zones according to degree from the fovea (2°, 4°, 6°, and 8°). We analyzed the correlation coefficients between the retinal sensitivity and the total retinal thickness (TRT), the length from the inner limiting membrane to the retinal pigment epithelium (RPE), and between the retinal sensitivity and the outer retinal thickness (ORT), the length from the outer plexiform layer to the RPE at each stimulus point.ResultsTRT showed moderate correlations with the retinal sensitivity at 2° (median ρ = 0.59 interquartile range (IQR) [0.38–0.72]), 4° (ρ = 0.59 [0.55–0.68]) and 6° (ρ = 0.60 [0.54–0.63]), and TRT was weakly-to-moderately related to the retinal sensitivity at 8° (ρ = 0.27 [0.19–0.48]). ORT exhibited strong correlations at 2° (ρ = 0.72 [0.60–0.81]), 4° (ρ = 0.71 [0.75–0.67]) and 6° (ρ = 0.70 [0.54–0.74]), and a weak-to-moderate correlations at 8° (ρ = 0.34 [0.29–0.53]). ORT was more strongly correlated with the retinal sensitivity compared to TRT (p = 0.018).ConclusionORT, rather than TRT, within 6° eccentricity was strongly correlated with the retinal sensitivity, suggesting that measuring ORT in those areas will help evaluate the macular status and progression in RP.

Structure-Function Relationship in Patients with Retinitis Pigmentosa and Hyperautofluorescent Rings

“…Point-to-point analysis revealed that greater retinal sensitivity was associated with the area of and within the hyperAF ring. In line with previous reports [ 15 ], ORT was more strongly correlated with retinal sensitivity than TRT. The hyperAF ring area and the longest diameter of the hyperAF ring were positively correlated with mean retinal sensitivity.…”

“…Regarding retinal thickness and retinal sensitivity, we observed that ORT was more strongly correlated with retinal sensitivity than TRT. Funatsu et al [ 15 ] investigated the retinal structure-function relationship in patients with RP by comparing microperimetry-3 images with co-registered OCT images. They showed that ORT was more strongly correlated with retinal sensitivity than TRT and suggested that these results may be due to photoreceptor cells being primarily injured in RP and that TRT can be affected by the thickness of the inner layers, which varies depending on the distance from the fovea and can be affected by the presence of an epiretinal membrane and degenerative thickening [ 15 , 20 ].…”

“…Funatsu et al [ 15 ] investigated the retinal structure-function relationship in patients with RP by comparing microperimetry-3 images with co-registered OCT images. They showed that ORT was more strongly correlated with retinal sensitivity than TRT and suggested that these results may be due to photoreceptor cells being primarily injured in RP and that TRT can be affected by the thickness of the inner layers, which varies depending on the distance from the fovea and can be affected by the presence of an epiretinal membrane and degenerative thickening [ 15 , 20 ]. Although the current study minimized the variability of TRT by excluding patients with epiretinal membranes, these results indicating that ORT is more strongly correlated with retinal sensitivity than TRT are reasonable because the outer retina is primarily affected, and the inner retina is relatively preserved in patients with RP [ 21 ].…”

Retinal Oxygenation in Inherited Diseases of the Retina

“…Outside zone 2 (3°–8°), a study by Konieczka et al found a reduction in mfERG responses corresponding to the reduction in the central retinal layer thickness [ 56 ]. Funatsu et al [ 62 ] reported in RCD patients reduced central retinal sensitivity measured by microperimetry corresponding to reduced outer retinal thickness at 6°–8°. Several studies on fundus autofluorescense imaging in RCD patients have paid attention to increased annular hyperautofluorescence in the parafoveolar area (within 3.0° to 10.5°), which is supposed to indicate a metabolic abnormality [ 63 , 64 ].…”

The qualitative assessment of optical coherence tomography and the central retinal sensitivity in patients with retinitis pigmentosa

“…To overcome these potential problems, relationships between the structure and function have been extensively investigated in order to utilize the objective and quantitative parameters obtained from spectral-domain optical coherence tomography (SD-OCT) to assess the central retinal sensitivity of patients with RP . Previously, among several quantitative parameters, the width of the inner segment ellipsoid zone (IS-EZ) [1,3,7,8,10,13,14,18,19,21,24] and thickness of the outer retinal layer [2,4,9,12,15,20,23] have been shown to be significantly correlated with the central visual sensitivity. However, in these quantitative analyses, the subjects should be restricted to patients with visual acuity better than a certain level or measurable structural changes for analyzing the correlation between structural parameters and the visual function [1,9,10,12,13,15,18,20,21].…”