Correlation between central subfield thickness, visual acuity and structural changes in diabetic macular edema

Abstract

Purpose: To correlate the central subfield thickness (CST) measured by Cirrus TM SD-OCT with best-corrected visual acuity (BCVA) and structural changes in diabetic macular edema (DME). Methods: The transversal study evaluated 200 patients with non-proliferative dia betic retinopathy (NPDR) and selected 55 eyes with DME between January, 2010 and April, 2011. Spectral domain OCT was performed in patients with type 2 diabetes and DME. CST and BCVA were correlated with the edema morphology and the ELM (external limiting membrane) integrity. Statistical tests were applied to validate the results. Results: There was no difference between genders in the NPDR classification. 47.3% of the patients showed moderate NPDR. The CST average for male was of 393.58 µm and 434.16 µm for female, with no statistically significant difference. The patients with continuous ELM showed lower CST average (368.73 µm) than those with disrupted ELM (521.43 µm). There was a strong correlation between the macular volume and CST (59.63%), but poor correlation between age and CST (2.9%). Also, there was a significant difference between the average CST and the type of macular edema. Patients with serous detachment showed higher CST average (488.71 µm) than those with cystoid macular edema (CME) and diffuse edema. Patients with severe NPDR showed higher CST average (491.45 µm), if compared to mild and moderate NPDR. Cystoid macular edema was the most common type of edema (49.1%) and showed the worse VA. Patients with disrupted ELM showed worse BCVA. Patients with higher CST showed worse BCVA. There was a significant difference between the CST average of the case group (407.6 ± 113,1 µm) and the control group (diabetic patients without DME: 252 ± 12.5 µm). There was also a significant difference in the BCVA variables and macular volume between case and control groups. Conclusion: The study suggests that the CST of diabetic patients with edema is higher than the control group, the increase in CST of diabetic patients with edema leads to worsening of BCVA and macular volume. Continuous ELM showed lower CST average, and the serous detachment showed higher CST average. Cirrus TM proved to be an important tool in the DME evaluation.

Clinical and Anatomical Features of the Central Part of the Retina in Diabetic Macular Edema

“…According to the group of authors [14][15][16] there is a significant correlation between the average thickness of macular area (OCT data) and visual acuity in patients with diabetes and diabetic retinopathy in laser and/or intravitreal therapy over time. [17][18][19] However, other studies have shown no correlation or its presence in a moderate degree and there is still no consensus on this matter. 20 Yohannan et al, 21 report a correlation between a sensitivity of retina and photoreceptor state in patients with diabetic macular edema (DME).…”

Indicators of Visual Prognosis in Diabetic Macular Oedema

“…An important consideration with the growing literature regarding the EZ is how to objectively and consistently evaluate disruption. Few studies have analyzed the percentage disruption of each layer, few have classified the EZ disruption into less than or more than 200 microns, while others have merely comment on the integrity [ 42 , 43 , 44 , 45 ]. Considering all the evidence on the effect of outer retinal changes on OCT on visual outcome, it can be concluded that a visible sub-foveal loss of ellipsoid layer or ELM and the percentage disruption are definite poor visual prognostic indicators [ 46 , 47 , 48 , 49 , 50 ].…”

Clinical applications of optical coherence tomography in the posterior pole: the 2011 José Manuel Espino Lecture – Part II

“…In patients with diabetes and diabetic retinopathy, single measurements of central foveal thickness using OCT were shown to correlate with visual acuity and to be a successful means of monitoring macular thickening before and after laser therapy 1 , 2 and/or intravitreous therapies. 3 – 5 However, other studies report conflicting results; some studies have shown no correlation while others have shown a moderate correlation, and this issue is still in discussion. 5 – 7 …”

“… 3 – 5 However, other studies report conflicting results; some studies have shown no correlation while others have shown a moderate correlation, and this issue is still in discussion. 5 – 7 …”

“…In patients with diabetes and diabetic retinopathy, some studies have shown that single measurements of the central foveal thickness, using OCT, correlate with visual acuity and are a successful means of monitoring macular thickening before and after therapy. 1 – 5 However, other studies have reported conflicting results. 6 – 7 Changes in diabetic macular edema can be accurately and prospectively measured with OCT, in both clinical trials and clinical practice.…”