Choroidal Thickness in Diabetic Eyes Using SD-OCT Enhanced Depth Imaging

Abstract

 

Purpose:

 

To measure choroidal thickness in the macular area in people with diabetes (PWD) using spectral-domain optical coherence tomography (SD-OCT) with an enhanced depth imaging (EDI) approach. To date, accurate choroidal thickness has not been reported in PWD.

 

Methods:

 

This was an observational study. Images were obtained from PWD by using EDI on SD- OCT (Spectralis OCT, Heidelberg, Germany). 7 sections, each comprised of 100 averaged scans (ART=100), were obtained within a 5×30 degree area. The choroidal thickness was measured between the outer edge of Bruch’s membrane and the inner edge of the presumed suprachoroidal space at 500-µm intervals of a horizontal section from 3 mm temporal to the fovea to the 3 mm nasal to the fovea, centred on the fovea. These interfaces were manually delineated independently by 2 clinicians (AS & JS) using ImageJ (NIH, US). A statistical analysis was performed on the SPSS 18 (SPSS Inc., Chicago, IL).

 

Results:

 

Scans were obtained from 28 eyes of 17 PWD (type 1= 4; type 2=13). Mean age was 53 years (range: 25-71). The mean thickness of the choroid at the fovea (±SD) was 245± 77µm, which was the thickest of the 13 positions measured (Table 1). There was decreased thickness with increasing distance from the foveal centre, especially in the nasal direction. The choroidal thickness negatively correlated with age (r=-0.347, p<0.01). Inter-observer correlation was statistically significant (r= 0.90, p<0.01).

 

Conclusions:

 

SD-OCT with an EDI approach allows the study, analysis and measurement of choroid in patients with diabetes. This technique can be useful to study the contributing role of the choroid in the pathophysiology of diabetic maculopathy.  

 

Keywords: diabetes • choroid • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)