Individual retinochoroidal layer thickness/volume analysis of the macula: effect of diabetes mellitus

Abstract

Purpose : To provide comprehensive description of the volume and thickness of individual retinochoroidal layer of the macula and to assess the relationship between the layer thickness/volume and diabetes mellitus.

Methods : We recruited subjects from the Singapore Indian Eye Study 2 (SINDI-2). The data of 402 subjects which had spectral domain optical coherence tomography (SD-OCT) raster scan images were used. Using SD-OCT, the thickness map of the 10 retinal layers and 1 choroidal layer, i.e., the retinal layer, retinal nerve fiber layer, ganglion cell layer, inner pexiform layer, inner nuclear layer, outer pexiform layer, outer nuclear layer, retinal pigment epithelial layer, inner retina layer, photoreceptor layer and choroidal layer were generated. The total volume and mean thickness of 9 ETDRS grid sectors were calculated from each layer,. After excluding eyes with diabetic retinopathy (n=39), the measured parameters of 196 eyes with diabetes and 166 healthy control eyes were compared.

Results : The mean age of the subjects was 61.0 years (range, 49 - 80 years). The total volume of each layer [mean (SD), mm³] was calculated as follows; retinal layer 8.4 (0.43), retinal nerve fiber layer 0.91 (0.13), ganglion cell layer 1 (0.11), inner plexiform layer 0.83 (0.08), inner nuclear layer 1 (0.07), outer plexiform layer 0.76 (0.06) outer nuclear layer 1.62 (0.18), retinal pigment epithelial layer 0.45 (0.05), inner retinal layer 6.12 (0.41), photoreceptor layer 2.52 (0.97) and choroidal layer 8.14 (1.78). Mean retinochoroidal layer thickness measured from 9 ETDRS grid sectors are shown in Table. There was no significant differences in the measured parameters between eyes with diabetes and healthy control eyes (Figure, all P > 0.05).

Conclusions : We establish normative database on the volume and thickness database of the 11 retinochoroidal layers in eyes with normal macula. The current study does not show the change of the retinochoroidal layers in diabetic patients without retinopathy compared with healthy non-diabetic controls.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

 

ETDRS = Early Treatment Diabetic Retinopathy Study, SD = standard deviation,

 

Bar graphs showing the retinochoroidal thickness at different docations in diabetic subjects without retinopathy and healthy non-diabetic subjects. Error bars represent SD.