Change in Choroidal Thickness Measurements in Diabetic Patients using Spectral Domain OCT

Abstract

Purpose: : To determine if the choroidal thickness in patients with diabetic retinopathy (DR) changes over time.

Methods: : A retrospective case review (2009 - present) identified 28 consecutive patients with DR, who underwent at least 2 foveal OCT scans, at least 6 months apart, using the Cirrus high definition OCT 1-line scanning protocol (Carl Zeiss Meditech Inc, Dublin, California, USA). The eye with the most advanced DR was selected as the study eye. DR was categorized into three groups based on clinical and OCT findings: non-proliferative DR (NPDR) (9 eyes), diabetic macula edema (DME) (10 eyes), or proliferative DR (PDR) (9 eyes). Subfoveal and parafoveal choroidal thickness measurements were manually calculated using the Cirrus linear measurement tool. In addition, choroidal thickness measurements from age-matched normal patients were used as controls. Differences between the respective DR groups at baseline and over time were analyzed and compared to age-matched controls.

Results: : No difference in choroidal thickness was detected between the NPDR patients and controls (p> 0.05). However, choroidal thickness was statistically significantly thinner in DME and PDR eyes compared to controls (p< 0.05 and p< 0.05, respectively). The average length of follow-up among all groups was 387 days. With a minimum of follow-up of 6 months, subfoveal choroidal thickness changed by -3.78 μm in the NPDR group (p = 0.747), -5.3 μm in the DME group (p = 0.739), and -12.44 μm in the PDR group (p = 0.339).

Conclusions: : Choroidal thickness appears to be decreased in patients with advanced diabetic retinopathy when compared to age-matched controls. Although reduced at baseline, choroidal thickness in diabetics does not appear to change appreciably over approximately one year. Longer term follow-up may be needed to better characterize the effect of advanced diabetic retinopathy on choroidal thickness.

Keywords: diabetes • choroid • imaging/image analysis: clinical