Characterization of microaneurysm closure after focal laser photocoagulation in diabetic macular edema

Abstract

Purpose: To characterize microaneurysm closure following focal laser photocoagulation in diabetic macular edema (DME) using simultaneous fluorescein angiography (FA) and spectral-domain optical coherence tomography (SD-OCT).

Design: Retrospective observational case series.

Methods: Leaking microaneurysms (n = 123) were analyzed in eyes (n = 29) with nonproliferative diabetic retinopathy (NPDR) that underwent navigated focal laser photocoagulation in DME and were followed at 3, 6, and 12 months. Closure of diabetic microaneurysms was characterized in detail following focal laser using SD-OCT.

Results: Closure rate of microaneurysms by both FA and SD-OCT was 69.9% (84/123), 79.7% (98/123), and 82.9% (102/123) at 3, 6, and 12 months, respectively. Microaneurysm closure rate increased at 6 and 12 months compared to 3 months (P < .003, P < .001). Over half of closed microaneurysms (45/86, 52.3%) left hyperreflective spots while the remaining half (41/86, 47.7%) disappeared without any hyperreflectivity by SD-OCT at 3 months. Hyperreflective spots decreased at 6 (36/99, 36.4%) and 12 months (17/102, 16.7%) with a concomitant increase in complete loss of reflectivity at 6 (63/99, 63.6%) and 12 months (85/102, 83.3%). Smaller outer and inner diameters and heterogeneous lumen reflectivity were positively associated with microaneurysm closure at 12 months (P < .0001, P < .001, P < .03).

Conclusions: Characterization of microaneurysms following focal laser photocoagulation resulted in hyperreflective spots and complete resolution of all reflectivity using SD-OCT. Smaller microaneurysms and those with heterogeneous lumen were positively associated with microaneurysm closure. These findings provide greater understanding of localized retinal changes following focal laser photocoagulation in DME treatment.

Figure 1

Lumens of leaking retinal microaneurysms characterized by simultaneous fluorescein angiography (FA) and spectral-domain optical coherence tomography (SD-OCT) Representative simultaneous FA (left) and SD-OCT images (right) of leaking microaneurysms (white and open arrow) are seen in the inner nuclear layer with adjacent intra-retinal cystic edema. The microaneurysm lumen with homogeneous reflectivity (top right, white arrow) has uniform reflectivity unlike the microaneurysm lumen with heterogeneous reflectivity (bottom right, open arrow) which contains irregular hyper-reflective spots.

Figure 2

Retinal microaneurysms characterized by spectral-domain optical coherence tomography following focal laser photocoagulation Leaking microaneurysms with a heterogeneous lumen (white and open arrows, top) in the inner nuclear layer with adjacent cystic edema were observed at baseline. At 6 months following navigated focal laser photocoagulation (bottom), a heterogeneous microaneurysm (white arrow) closed leaving hyper-reflective spots in its original location with resolution of adjacent cystic edema (bottom left). Another heterogeneous microaneurysm (open arrow) closed leaving an absence of any reflectivity following 6 months after laser photocoagulation (bottom right).

Figure 3

Progression of retinal microaneurysm closure characterized by spectral-domain optical coherence tomography following focal laser photocoagulation Microaneurysm with homogeneous lumen (white arrow) was observed in the inner nuclear layer with adjacent cystic fluid (top). At 3 months following focal laser photocoagulation, the microaneurysm has a persistently open lumen with cystic fluid (second row). At 6 months, the microaneurysm lumen has closed collapsing with decreased cystic fluid (third row). At 12 months (bottom), the lumen has been obliterated with leaving hyper-reflective spots in its original location with resolution of intra-retinal fluid.

Figure 4

Initially closed retinal microaneuryms may re-open following focal laser photocoagulation At baseline, a microaneurysm with a heterogeneous lumen (white circle) was observed in the inner nuclear layer with adjacent cystic fluid (top). At 3 months following focal laser photocoagulation, the microaneurysm has a persistently open lumen with decreased surrounding intra-retinal cystic fluid (second row). Disruption of the outer retina and retinal pigment epithelium by laser photocoagulation is also seen. At 6 months, the microaneurysm lumen has collapsed leaving hyper-reflective spots in its original location with resolution of adjacent intra-retinal fluid (third row). At 12 months, the microaneurysm has re-opened in the same location where hyper-reflective spots were seen previously (bottom).