Abstract
Purpose: :
To characterize Diabetic Macular Edema (DME) morphological patterns in responders and non-responders to anti-VEGF treatment using Spectral Domain OCT (HD-CirrusTM).
Methods: :
In a retrospective study, 20 patients with DME submitted to intravitreal injections of anti-VEGF Lucentis were selected according to their response to treatment after 6 months: 10 patients which had clear improvement of Best Corrected Visual Acuity (BCVA) (≥ 10 letters) and 10 patients with worsening or no improvement of BCVA. All patients performed BCVA measurements using ETDRS charts and HD-OCT at baseline, 3 and 6 months after initial injection. In each visit, the OCT scans were graded and classified in 5 types: type 1-diffuse DME without cystoid spaces, type 2-inner cystoid DME, type 3-outer cystoid DME, type 4-cystoid DME with cystoid spaces involving both inner and outer retina layers, and type 5-serous retinal detachment. Presence of epiretinal membrane (ERM) or retina traction was also evaluated. A decision and classification tree (CART) was used to identify OCT morphological patterns on both groups.
Results: :
At baseline the group with good response to treatment presented the following patterns: 7 cases (70%) of DME type 1; 3 cases (30%) of DME type 2; 10 cases (100%) of DME type 3 and 5 cases (50%) of DME type 4, while the group with poor response to treatment presented 4 cases (40%) of DME type 1; 7 cases (70%) of type 2; 10 cases (100%) of type 3 and 7 cases (70%) of type 4. Poor response to treatment appears to be predominantly associated with type 2 and type 4 DME (70% of cases on both types vs 30% and 50%, respectively in the group with good response) while DME type 1 is more frequent in the group showing good response to treatment (70% of cases vs 40% in the group with poor response) (CART classification error ≤ 0,250). DME type 5 was only observed in 2 eyes of the good responders group. ERM and retina traction were observed in 3 and 1 eyes in each group and showed no change during the 6 months of treatment.
Conclusions: :
Presence of cystoid spaces in the inner retina layers at baseline appears to be more frequent in non responders to treatment indicating that it may be a predictor of worse response to anti-VEGF treatment while diffuse macular edema without cystoid spaces appears to be associated with good response to anti-VEGF treatment. Assessment of morphological patterns of diabetic macular edema with OCT may give useful information about the expected outcome of anti-VEGF treatment.
Keywords: diabetic retinopathy • edema • visual acuity