Assessment of Retinal Structural and Functional Characteristics in Eyes with Autoimmune Retinopathy.

PURPOSE: To evaluate the thicknesses of individual retinal layers, and the correlation between structural changes and functional loss using spectral domain optical coherence tomography (SD-OCT) scans and electroretinograms (ERG), in eyes with autoimmune retinopathy (AIR). METHODS: SD-OCT raster scans of 12 eyes from 6 patients serologically diagnosed with AIR were evaluated. Retinal layers were segmented along a 5 mm horizontal scan passing through the fovea. Retinal layers analyzed include full retinal thickness (FRT), retinal pigment epithelium and Bruch's membrane complex (RPE+BM complex), photoreceptor layer (PRL), inner nuclear layer (INL), combined ganglion cell and inner plexiform layers (GCL+), nerve fiber layer (NFL), and combined GCL+ and NFL layers (GCL+/NFL). Changes in the thicknesses of the layers were assessed in 0.5 mm increments along the B-scan in the central, nasal, and temporal regions. These recorded values were compared to corresponding values of 51 eyes from 51 subjects with no known ocular pathology. Full-field ERGs were obtained at corresponding visits and were interpreted by a grader masked to the diagnoses and OCT findings. RESULTS: The mean age of the patients was 59.5 years (range, 33-83), with 4 males (66.6%). Within the control population of 51 subjects, mean age was 51.5 years (range, 40-75), with 25 males (49%). Eyes with AIR showed a loss of retinal tissue compared to eyes with no known ocular pathology at the fovea. Specifically, the FRT, RPE+BM complex, and PRL exhibited thinning of statistically significance. ERG findings demonstrated a functional deficit which showed a good correlation with structural loss. Fifty (50) percent of eyes experienced central photoreceptor (rod and cone) dysfunction and 75% of eyes displayed peripheral photoreceptor (rod and cone) dysfunction. CONCLUSIONS: Eyes with AIR show a loss of retinal tissue compared to eyes with no known ocular pathology. The greatest loss appears to occur in the RPE and PRL. ERG findings correlate strongly with the loss of tissue seen in these layers. Thus, therapeutic options may be targeted to preserve these regions of the retina.

Longitudinal comparison of visual acuity as measured by the ETDRS chart and by the potential acuity meter in eyes with macular edema, and its relationship with retinal thickness and sensitivity.

PURPOSE: To evaluate the relationship between visual acuity as measured by the Early Treatment Diabetic Retinopathy Study (ETDRS) chart and by the potential acuity meter (PAM) with retinal thickness and sensitivity measured by a combined microperimetry/optical coherence tomography system (OCT). METHODS: Forty-four patients with macular edema (ME) were included in a prospective observational study. Visual acuity (VA) was assessed using the ETDRS chart (with best correction) as well as by the PAM. Retinal thickness and sensitivity was measured by an automatic fundus perimetry/tomography system. RESULTS: Best-corrected VA using the ETDRS chart ranged from 20/20 to 20/400 (median: 20/50). VA measured by the PAM without correction ranged from 20/20 to 20/400 (median: 20/40). The mean retinal thickness was 369.57 µm (s.d.: 140.28 µm) on spectral domain-OCT and the mean retinal sensitivity was 8.12 decibels (dB) (s.d.: 5.78 dB). The mean LogMAR value using the ETDRS chart was 0.43, whereas it was 0.38 using the PAM (P-value: 0.009). CONCLUSIONS: VA values measured by the PAM were statistically significantly better than those measured by the ETDRS chart in eyes with ME secondary to various retinal vascular and uveitic diseases. VA measured by the PAM may be a more sensitive predictor of macular function than that obtained by ETDRS testing in eyes with ME.

Association of retinal vessel calibre and visual outcome in eyes with diabetic macular oedema treated with ranibizumab.

PURPOSE: The study aims to identify the association between the baseline retinal vascular calibre and visual outcome of patients with diabetic macular oedema (DMO) treated with intravitreal ranibizumab. METHODS: The 1-M field (as defined in the ETDRS study) of the digital colour fundus photographs of DMO patients who had been treated primarily with ranibizumab in a clinical trial was assessed. Of the 84 patients, 25 had gradable retinal photographs that could be subjected to analyses by the Interactive Vessel Analysis (IVAN) software at baseline. The average retinal vascular calibre of the six largest venules (CRVE) and the six largest arterioles (CRAE) in the peripapillary area (0.5 and 1 disc diameter from the optic disc margin) was measured. The relationship between CRVE and CRAE at baseline and the change in visual acuity at month 12 was assessed using the Mann-Whitney U test. RESULTS: Ten eyes from 10 patients who had shown an improvement of ≥2 lines of best corrected visual acuity (BCVA) at month 12 had a wider baseline CRVE (248.3±24.5 µm) compared with the 15 eyes from 15 patients who did not show the improvement of ≥2 lines (226.6±44.8 µm, P<0.05). The baseline CRAE did not differ significantly in these patients (156.1±22.7 vs 142±17.5 µm, P=0.17). CONCLUSIONS: A wider baseline retinal venular calibre may be a predictor of better visual outcome in DMO eyes treated with ranibizumab. Further prospective studies with a larger sample size and a broader range of disease severity and visual acuity are needed to confirm this finding.