Microaneurysm turnover is a predictor of diabetic retinopathy progression.

AIM: To analyse retinopathy phenotypes and microaneurysm (MA) turnover in mild non-proliferative diabetic retinopathy (NPDR) as predictors of progression to diabetic central-involved macular oedema (CIMO) in patients with type 2 diabetes mellitus (DM) in two different ethnic populations. METHODS: 205 patients with type 2 DM and mild NPDR were followed in a prospective observational study for 2 years or until development of CIMO, in two centres from different regions of the world. Ophthalmological examinations, including best-corrected visual acuity (BCVA), fundus photography with RetmarkerDR analysis, and optical coherence tomography (OCT), were performed at baseline and 6 12 and 24 months. RESULTS: 158 eyes/patients reached either the study endpoint, CIMO (24) or performed the last study visit (24-month visit) without developing CIMO (134). From the eyes/patients in analysis, 27 eyes (17.1%) progressed to more advanced ETDRS (Early Treatment Diabetic Retinopathy Study) levels: 6 progressed to mild NPDR (level 35), 15 progressed to moderate NPDR (level 43), 5 progressed to moderately severe NPDR (level 47) and 1 progressed to high risk PDR (level 71). Worsening in ETDRS level is associated with phenotype C (p=0.005). From the 130 eyes/patients with a low MA turnover, 18 (13.8%) eyes/patients had an increase in ETDRS level, and from the 19 eyes/patients with a high MA turnover, 9 (47.4%) had an increase in ETDRS level (p<0.001). CONCLUSION: Eyes in the initial stages of diabetic retinopathy show different phenotypes with different risks for progression to CIMO. In phenotype C, MA turnover correlates with ETDRS grading worsening and development of CIMO.

Different phenotypes of the appearance of the outer plexiform layer on optical coherence tomography.

PURPOSE: To present a selected case series of different phenotypes of the normal outer plexiform layer (OPL) visualized by optical coherence tomography (OCT). METHODS: Five cases were selected to represent the spectrum of appearances of the OPL in this case series. Categorical descriptions of each manifestation were then developed. Additional SD-OCT scans were obtained from a normal volunteer to further support the hypothesis. RESULTS: The inner one-third of the OPL typically appears hyperreflective on OCT, while the outer two-thirds (Henle fiber layer) may have a more varied appearance. Six different phenotypes of Henle fiber layer reflectivity were noted in this series, and classified as: bright, columnar, dentate, delimited, indistinct, and dark. The brightness of the Henle fiber layer appears to depend on the geometric angle between the OCT light beam and the axonal fibers in this portion of the OPL. This angle appears to be a function of the natural orientation of the Henle fiber layer tissue (θN), the existence of subretinal pathology that alters the angle of the neurosensory retina (θ(P)), and the tilt angle of the tissue on the B-scan (θ(T)) due to decentered OCT acquisition. CONCLUSIONS: Since accurate interpretation of the OPL/ONL boundary is of vital importance to study the thickness of ONL, location of cystoid lesions, hyperreflective crescents over drusen, et al., our case series may aid better understanding of the OPL appearance in SD-OCT. In the absence of clear delineation, it may be most correct to refer to indistinct OPL and ONL together as the photoreceptor nuclear axonal complex (PNAC).

Evaluation of the axial location of cystoid spaces in retinal vein occlusion using optical coherence tomography.

PURPOSE: To analyze the axial distribution of intraretinal cystoid changes in patients with retinal vein occlusion (RVO), incorporating a new hypothesis about the optical coherence tomographic boundary between the outer nuclear layer and the outer plexiform layer. METHODS: Data were collected from patients with RVO who underwent spectral domain coherence tomography imaging. For each image set, certified graders evaluated each retinal layer for cystoid macular edema, defined as hyporeflective intraretinal cystoid spaces. Subretinal fluid, if present, was also noted. RESULTS: Forty-eight eyes were evaluated (24 branch RVO, 18 central RVO, 6 hemiretinal vein occlusion). Cystoid macular edema was present in 30.8% of eyes in outer nuclear layer, 77.9 % in outer plexiform layer, 77.9 % in inner nuclear layer, 36.9 % in inner plexiform layer, 48.8 % in ganglion cell layer, and 4.9% in nerve fiber layer. Subretinal fluid was assessed as present in 23.8% of patients. The presence of subretinal fluid correlated most strongly with cystoid changes in the outer nuclear layer (r = 0.514, P = 0.001) but was not significantly correlated with these changes in the superficial retina. CONCLUSION: Use of spectral domain coherence tomography allows precise characterization of the axial location of cystoid spaces in RVO and highlights the frequency of fluid accumulation in the outer plexiform layer and inner nuclear layer. Using updated definitions, cystoid macular edema seems to occur less frequently in the outer nuclear layer, but when it does so, it is often associated with subretinal fluid. Future longitudinal studies, documenting the axial progression of such changes, and their response to treatment, may be of clinical relevance as pharmacotherapeutic options evolve.

Juxtapapillary pigment epithelium detachment observed in asymptomatic participants using optical coherence tomography.

PURPOSE: To use three-dimensional optical coherence tomography (3D-OCT) to assess the prevalence of juxtapapillary retinal pigment epithelial detachments (jPED) in an asymptomatic population. METHODS: Asymptomatic participants (i.e., family members of patients) were prospectively recruited over a 6-month period. Each subject completed a questionnaire prior to the acquisition of two undilated 45° fundus images and two undilated raster 3D-OCT scans (512 × 128) covering the macula and optic nerve from each eye using 3D-OCT-1000. Fundus images were graded for the presence of peripapillary atrophy (PPA), peripapillary pigment (PPP), drusen in the macula, and drusen elsewhere, whereas 3D-OCT scans were assessed for the presence of jPED, drusen in the macula, and drusen elsewhere. RESULTS: In all, 276 eyes from 138 participants were evaluated. Mean participant age was 37.6 years (range: 18-74 years; SD: 15.5 years). In all, 87 jPEDs were detected in 26.1% (36/138) of asymptomatic participants (25 bilateral and 11 unilateral) or 17.0% (47/276) of asymptomatic eyes (23 in the right eye and 24 in the left). The maximum height of jPED was 198.3 ± 53.8 (range: 101.8-376.0) µm. The minimum distance of jPED to the border of optic nerve head (OPN) was 2.6 ± 11.1 (range: 0-61.9) µm. The occurrence of jPEDs or drusen elsewhere by subjects increased statistically with increasing age (P < 0.001, respectively). CONCLUSIONS: In this study, definite jPEDs were observed by OCT in asymptomatic participants, which were not seen with fundus photography. jPEDs were seen more commonly with increasing age, although it is not known whether these lesions represent deposition of drusen-like material or aborted choroidal neovascularization adjacent to the natural break in Bruch's membrane at the optic disc.