Effect of Leaking Foveal Microaneurysms on the Treatment of Center-Involving Diabetic Macular Edema: A Pilot Study

Abstract

Purpose: Evaluate the effect of foveal leaking microaneurysms (MAs) on the required number of intravitreal ranibiz­umab (IVR) injections in the treatment of center-involving diabetic macular edema (DME) when treated with focal/grid laser. Design: A pilot study of prospective, nonrandomized, multicenter clinical trial. Methods: This study enrolled 21 eyes with DME for which pro re nata IVR injections were combined with short-pulse focal/grid laser. At 12 months, best-corrected visual acuity (BCVA), central subfield macular thickness (CMT), and the required number of IVRs to maintain CMT < 300 µm were compared between eyes with or without foveal leaking MAs, termed the MA(+) and MA(–) groups, respectively. Results: Significant CMT improvements (p < 0.0001) and increased BCVA of 4.0 ± 8.5 letters were observed at 12 months. The MA(–) group required significantly fewer IVRs than did the MA(+) group (mean: 4.9 ± 3.0 vs. 8.6 ± 3.0; p = 0.0306). In the latter 6 months of the 1-year follow-up, 50% (4/8) of MA(–) eyes did not require any IVR administration to sustain CMT < 300 µm. Conclusions: A combination therapy of short-pulse focal/grid laser and reduced IVR injections appeared noninferior to previous reports of IVR monotherapy. Further large-scale investigations are warranted.

Comparison of multicolor scanning laser ophthalmoscopy and optical coherence tomography angiography for detection of microaneurysms in diabetic retinopathy

“…However, its detection rate is lower than that of FA (41–64% compared with that of FA) 17 – 20 . Moreover, in OCTA, MA is not always shown as a dot-like hyperfluorescence as in FA, but there are variations in the appearance, such as capillary loops, dilated capillary segments, and focal dilatation 10 . Thus, the specificity of MAs is 75% compared with that of FA, which is low probably because it is difficult to distinguish from normal capillaries 20 .…”

“…However, direct photocoagulation of MAs is sometimes effective in DME 8 – 14 . Because photocoagulation of MA can reduce the number of the anti-VEGF therapies 10 , 11 , it is beneficial for patients, the medical staff, and the medical economy.…”

“…Currently, fluorescein angiography (FA) is the gold standard of MA detection 7 , 10 , 11 . Although MAs could be clearly detected using FA, it has the major drawback of invasiveness 15 , 16 .…”

Regional Variety of Reduction in Retinal Thickness of Diabetic Macular Edema after Anti-VEGF Treatment

“…It has been reported that the therapeutic effect of anti-VEGF drugs tends to be less effective in focal DME than in diffuse DME [ 20 ]. Hirano et al showed that the number of ranibizumab injections required to achieve a stable improvement in edema was significantly higher when MA was present in the neighboring foveal avascular zone (FAZ) in the center of DME [ 17 , 21 ]. In addition, Lee et al reported that OCT angiographic analysis revealed that small vascular flow density in the deep capillary plexus, large FAZ area, and a large number of adjacent MAs are characteristics of cases with poor response to anti-VEGF therapy [ 22 ].…”

Role of Microaneurysms in the Pathogenesis and Therapy of Diabetic Macular Edema: A Descriptive Review

“…Pericyte loss occurs in both diabetic and galactose-fed dogs and is characterized by changes in retinal vessels, such as MAs, hemorrhage, and the formation of non-perfused areas, similar to those seen in human DR [ 36 , 37 , 38 ]. Experimental evidence suggests that these changes can be prevented by aldose reductase inhibitors (ARI) [ 36 , 39 , 40 ]. Excess sugar alcohol (polyol) accumulation, catalyzed by the enzyme aldose reductase (AR) during hyperglycemic conditions, has been implicated in the pathogenesis of DR. Immunohistochemical studies have demonstrated that there is abundant AR expression in pericytes isolated by trypsin digestion from human and dog retinas [ 41 ].…”