The Effects of Macular Ischemia on Visual Acuity in Diabetic Retinopathy

Abstract

PURPOSE.To investigate the impact of diabetic macular ischemia (DMI) on visual acuity (VA), through the analysis of novel fluorescein angiography (FA) parameters.METHODS. Data were retrospectively collected over a 6-month period. DMI severity was graded using Early Treatment Diabetic Retinopathy Study (ETDRS) protocols. Custom software was used to quantify areas of the foveal avascular zone (FAZ), and of capillary nonperfusion over the papillomacular nerve fiber layer bundle, and temporal macula, and associations tested with VA. RESULTS.A total of 488 patients with type 2 diabetes mellitus and FAs of sufficient quality to allow detailed quantitative analyses were included. ETDRS-DMI severity was graded as: none, 39.7%; questionable, 18.4%; mild, 25.2%; moderate, 11.0%; and severe, 5.6%. Median FAZ areas were 0.19 mm CONCLUSIONS. Diabetic macular ischemia is associated with reduced VA in eyes with moderate to severe ETDRS-DMI grades of ischemia but preserved in milder grades. In addition, we describe the independent association of papillomacular nerve fiber bundle ischemia with reduced VA. (Invest Ophthalmol Vis Sci.

Macular ischemia and outcome of vitrectomy for diabetic macular edema

“…Perifoveal capillary closure induces FAZ enlargement, which is one of the main signs of progression of diabetic retinopathy [33]. Diabetic macular ischemia is demonstrated by the enlargement of the FAZ and by the loss of retinal capillaries in the macula [34][35][36]. The enlarged FAZ and resultant macular ischemia may lead to macular edema [37].…”

Longitudinal comparison of visual acuity as measured by the ETDRS chart and by the potential acuity meter in eyes with macular edema, and its relationship with retinal thickness and sensitivity

“…The impact of edema on VA measured with the ETDRS chart has been reported previously. 16,17 Sim et al 16 reported a decrease in VA measured with the ETDRS chart in eyes with DME, whereas Taylor et al 17 investigated the association between ME and impaired VA measured with the ETDRS chart in those with UME. To the best of our knowledge, our report is the first to evaluate the relationship between retinal thickness and VA as measured by the PAM/Prevue.…”

“…A decrease in ETDRS-measured VA in eyes with diabetic ME (DME) and in those with uveitic ME (UME) has been reported. 16,17 The relationship between BCVA measured with the ETDRS chart and retinal sensitivity has been also reported. In previous studies, after adjustment for other factors such as retinal thickness, there has been no association between BCVA measured with the ETDRS chart and retinal sensitivity in eyes with DME and in those with UME.…”

Functional outcome of macular edema in different retinal disorders

“…Previous treatment for macular edema, including focal macular laser, as well as the development of secondary changes such as epiretinal membranes result in the development of scotomas, metamorphopsia and a progressive deterioration in visual function. In addition, development of macular ischemia may further reduce visual function as well as affect response to treatment (Douvali et al, 2014;Sim et al, 2013). The development of these changes can be gradual and similarly their effect on visual function may take many years before patients are aware of any change in their vision.…”