Abstract
Purpose :
We performed a prospective cohort clinical study to compare the macular choroidal thickness and volume measured by a spectral-domain optical coherence tomography (SD-OCT) in patients with type 2 diabetes with absent or mild nonproliferative diabetic retinopathy without renal impairment (estimated glomerular rate, ≥60 ml/min per 1.73 m2).
Methods :
We studied 62 eyes of 33 patients with type 2 diabetes without clinically significant diabetic retinopathy divided into two groups based on the presence of normal urinary albumin excretion or microalbuminuria. All patients underwent complete ophthalmic examination after pupil dilatation: indirect ophthalmoscopy, digital retinography and ocular coherence tomography. Eyes with spherical equivalent between ± 3.0 diopters were included, and any subject with other retinal or choroidal pathology was excluded. Patients were imaged with a SD-OCT (Spectralis, Heidelberg Engineering, Germany) using the enhanced depth-imaging mode. Choroidal thickness was measured from the outer edge of the hyperreflective retinal pigment epithelium to the inner sclera at the fovea, 500 µm temporal and nasal to the fovea. Choroidal volume was mapped using the ETDRS grid (Fig. 1A and 1B). To reduce the effects of diurnal variations, all examinations were performed within 3 hours on the same daytime.
Results :
There were no differences in baseline characteristics between groups (P > 0.05). The choroid was significantly thinner in the group with microalbuminuria (284.03±12.56 µm vs. 228.87±14.44 µm, p<0.001). The average total choroidal volume of the entire ETDRS area was 7.63±2.24 mm3 in patients with diabetes and normal urinary albumin excretion, and 7.22±1.13 mm3 in those with diabetes and microalbuminuria (p=0.541). Although the choroidal volume of the patients with microalbuminuria was similar in all subfields compared to the other group, there was an evident hemisphere asymmetry between both groups when we analyze each volume distribution separately.
Conclusions :
Overall macular choroidal thickness in patients with diabetes and microalbuminuria was thinner than in those with diabetes and normal albumin excretion. Comparing the choroidal volume distribution map, there was a hemisphere asymmetry between groups.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.