Purpose. To evaluate the changes in thickness of individual inner and outer macular and peripapillary retinal layers in diabetes.Methods. 124 subjects (124 eyes) were enrolled: 74 diabetics and 50 controls. Macular edema, proliferative diabetic retinopathy (DR), any intraocular treatment and refractive error>6diopters were the main exclusion criteria. Full ophthalmic examination, stereoscopic fundus photography, and spectral domain-OCT were performed. After automatic retinal segmentation (layering) in 5 layers, the thickness of each layer was calculated, and values compared among groups.Results. Thirty patients had no DR, 44 patients had non proliferative DR. A significant increase of inner plexiform and nuclear layers was found in DR eyes versus controls (P<0.001). A significant decrease (P<0.01) of retinal nerve fiber layer (RNFL) and at specific sites of retinal ganglion cell layer (P=0.02) was documented in the macula. In the peripapillary area there were no differences between diabetics and controls.Conclusions. Decreased RNFL thickness and increased INL/OPL thickness in diabetics without DR or with initial DR suggest early alterations in the inner retina. On the contrary, the outer retina seems not to be affected at early stages of DM. Automatic intraretinal layering by SD-OCT may be a useful tool to diagnose and monitor early intraretinal changes in DR.

Background: Early age-related macular degeneration (AMD) has been correlated with different functional alterations, but the exact relationship between fundus lesions and overlying sensitivity is not well known. The aim of this study was to compare fundus-related sensitivity (microperimetry) and fundus autofluorescence (FAF) of the macular area with drusen and pigment abnormalities in early AMD. Methods: 13 consecutive patients with early AMD and visual acuity of 20/20 were studied by means of microperimetry, which automatically analyses macular light differential threshold and fixation patterns. Fundus colour photo and FAF of the macular area were recorded on the same day. Microperimetry was exactly (topographically) superimposed over FAF images. Results: Macular sensitivity significantly decreased over large drusen (11.2 ± 5.6 dB, p<0.0001) and over pigment abnormalities (13.1 ± 3.6 dB, p<0.0001). When both characteristics were present the reduction was greater if compared with its absence (9.6 ± 4.3 versus 15.0 ± 4.5 dB, p<0.0001). Sensitivitity reduction was significant in areas with altered FAF when compared with areas with normal FAF (p<0.0001). Conclusions: Increased FAF in early AMD has a functional correlate exactly quantified by microperimetry. In retinal areas affected by early AMD retinal sensitivity deteriorates, despite good visual acuity. Microperimetry may allow the early detection of functional impairment caused by these lesions. Both microperimetry and FAF may be useful to monitor AMD progression.

The purpose of this study was to evaluate and compare microperimetry and fundus autofluorescence (FAF) after subthreshold micropulse diode laser versus modified Early Treatment Diabetic Retinopathy Study photocoagulation for clinically significant diabetic macular edema. A prospective randomized clinical trial including 62 eyes (50 patients) with untreated, center-involving, clinically significant diabetic macular edema was performed. All patients underwent best-corrected visual acuity determination (logarithm of the minimum angle of resolution), slit-lamp biomicroscopy, FAF, optical coherence tomography, microperimetry (macular sensitivity), and fluorescein angiography before and after treatment. Best-corrected visual acuity, optical coherence tomography, microperimetry, and FAF were repeated at 1-, 3-, 6-, 9-, and 12-month follow-up examinations. Fluorescein angiography was performed at baseline and at 6 and 12 months. Before treatment, demographic and macular parameters were not different between the two treatment groups. At 12 months, best-corrected visual acuity remained stable in both groups (P = 0.41 and P = 0.82), mean central retinal thickness decreased in both groups (P = 0.0002 and P < 0.0001), and mean central 4 degrees and 12 degrees retinal sensitivity increased in the micropulse diode laser group (P = 0.02 and P = 0.0075) and decreased in the Early Treatment Diabetic Retinopathy Study group (P = 0.2 and P = 0.0026). There was no significant difference in either best-corrected visual acuity or central retinal thickness between the 2 treatment groups (P = 0.48 and P = 0.29), whereas there was a significant difference in 4 degrees and 12 degrees retinal sensitivity (P = 0.04 and P < 0.0001). Fundus autofluorescence never changed in the micropulse diode laser group even after retreatment. In the Early Treatment Diabetic Retinopathy Study group, FAF increased up to 9 months and decreased in 6 eyes (20%) at 12 months. Micropulse diode laser seems to be as effective as modified Early Treatment Diabetic Retinopathy Study laser photocoagulation in the treatment of clinically significant diabetic macular edema. Micropulse diode laser treatment does not determine any change on FAF showing (at least) nonclinically visible damage of the retinal pigment epithelium. Microperimetry data encourage the use of a new, less aggressive laser therapeutic approach in the treatment of clinically significant diabetic macular edema.

Purpose. To evaluate the presence of hyperreflective spots (HRS) in diabetic patients without clinically detectable retinopathy (no DR) or with nonproliferative mild to moderate retinopathy (DR) without macular edema, and compare the results to controls.Methods. 36 subjects were enrolled: 12 with no DR, 12 with DR, and 12 normal subjects who served as controls. All studied subjects underwent full ophthalmologic examination and spectral domain optical coherence tomography (SD-OCT). SD-OCT images were analyzed to measure and localize HRS. Each image was analyzed by two independent, masked examiners.Results. The number of HRS was significantly higher in both diabetics without and with retinopathy versus controls (P<0.05) and in diabetics with retinopathy versus diabetics without retinopathy (P<0.05). The HRS were mainly located in the inner retina layers (inner limiting membrane, ganglion cell layer, and inner nuclear layer). The intraobserver and interobserver agreement was almost perfect (κ>0.9).Conclusions. SD-OCT hyperreflective spots are present in diabetic eyes even when clinical retinopathy is undetectable. Their number increases with progressing retinopathy. Initially, HRS are mainly located in the inner retina, where the resident microglia is present. With progressing retinopathy, HRS reach the outer retinal layer. HRS may represent a surrogate of microglial activation in diabetic retina.

Purpose: To investigate macular and peripapillary choroidal thickness (CT) in diabetic patients with and without diabetic retinopathy (DR). Methods: One hundred and fifty subjects were enrolled: 102 diabetic patients (102 eyes) and 48 normals, as controls. Exclusion criteria were previously treated DR, refractive error higher than ±3 diopters, and treated or untreated glaucoma. All patients underwent full ophthalmic examination, stereoscopic color fundus photography, and spectral domain optical coherence tomography (RS-3000; Nidek). Spectral domain optical coherence tomography examination consisted of linear scans, 6 mm in length, centered onto the fovea, and circle scan positioned around the optic disk (3.46 mm in diameter). Choroidal thickness was measured manually at the fovea and at 1, 2, and 3 mm distance along all scans in the macula. Peripapillary CT was measured at eight points along the circle scan. All measurements were performed independently by 2 masked graders. Results: Mean age was not significantly different between patients with diabetes and controls. In the macular area, CT was significantly lower in the nasal quadrant versus all other quadrants (P < 0.0001), in both groups. In the peripapillary area, CT was significantly lower in the inferior quadrant versus all other quadrants (P < 0.05), in both groups. Mean macular and peripapillary CT progressively and significantly decreased with increasing level of DR (nonproliferative and proliferative DR vs. controls, P < 0.05). No significant CT difference was found between controls and diabetic eyes without detectable DR. Diabetic macular edema did not influence CT. Interobserver coefficient of repeatability was 28.8 (95% confidence interval, 24.8–32.8) for foveal measurements and 13.0 (95% confidence interval, 11.2–14.8) for peripapillary measurements. Pearson correlation coefficient was 0.99, and P <0.0001 for all measurements. Conclusion: Choroidal thickness is reduced in diabetic eyes and parallels appearance and evolution of DR. Spectral domain optical coherence tomography clearly confirms in vivo previously reported histopathologic observations. The role of choroid in the pathophysiology of DR needs to be adequately investigated.

Purpose. To compare the changes in macular sensitivity (microperimetry) and macular thickness with different degrees of diabetic macular edema. methods. Sixty-one eyes of 32 consecutive diabetic patients were included in this cross-sectional study. All included eyes underwent functional and morphologic examination of the macular area. Best corrected visual acuity (ETDRS charts), macular sensitivity, and macular thickness were quantified. Lesion-related macular sensitivity and retinal fixation were investigated with an advanced, automatic microperimeter. Optical coherence tomography (OCT) was used to quantify macular thickness. results. The 61 included eyes were graded, by two retinal specialists, for diabetic macular edema as follows: 16 were graded as no macular edema (NE), 30 as non–clinically significant macular edema (NCSME), and 15 as clinically significant macular edema (CSME). Macular thickness significantly increased from the NE to the CSME group (P < 0.0001), whereas macular sensitivity significantly decreased from the NE to the CSME group (P < 0.0021). A significant correlation coefficient was noted between retinal sensitivity and normalized macular thickness (r = −0.37, P < 0.0001). Linear regression analysis showed a decrease of 0.83 dB (P < 0.0001) for every 10% of deviation of retinal thickness from normal values. Visual acuity and central macular sensitivity correlated significantly in the NCSME group (r = −0.6, P = 0.0008), but not in the NE (r = −0.144, P = 0.6) or in the CSME (r = −0.46, P = 0.11) groups. conclusions. Macular edema may be better documented by adding macular sensitivity mapping by microperimetry to macular thickness measurement by OCT and visual acuity determination because macular sensitivity seems to be a relevant explanatory variable of visual function, independent of macular thickness data. Moreover, microperimetry may be of value in predicting the outcome of diabetic macular edema, because it incorporates a functional measure that may supplement the predictive value of OCT and visual acuity.