Visual acuity and perimetry as measures of visual function in diabetic macular oedema

Abstract

Aims/hypothesis: We examined to what extent visual acuity and perimetric sensitivity as measures of central and paracentral visual function would be useful for evaluating the presence and severity of diabetic macular oedema. Materials and methods: We evaluated 59 eyes of 59 diabetic patients by identifying the presence (n=20) or absence (n=39) of macular oedema on stereo fundus photographs. The area of oedema and its distance to the centre of the macula were measured. Ischaemic macular damage was quantified by measuring the foveal avascular zone and adjacent perifoveolar intercapillary areas on fluorescein angiograms. Visual function was assessed by visual acuity charts and by short-wavelength perimetry and standard white-on-white perimetry of the central 10°f ield. Results: Visual acuity did not differ between eyes with and without macular oedema. In eyes with oedema, visual acuity was correlated to the distance of the oedema from the centre of the macula (log of minimum angle of resolution {LogMar} score decreased by 0.15/mm; p=0.006) and to the thickness of the retina when the centre was affected (LogMar score decreased by 0.003/μm of thickness; p=0.0002). Multivariate analyses confirmed the results (R 2 =0.46 and 0.77, respectively). Short-wavelength perimetry sensitivity was more depressed in eyes with oedema (p=0.033) but was not significantly associated with the presence of oedema after correction for macular ischaemic damage. There was no correlation between these field defects and the severity of oedema. Conclusions/interpretation: Visual acuity was a useful measure of visual function in diabetic macular oedema involving the centre. Visual field defects were more common in eyes with macular oedema but reflected ischaemic damage of the macula rather than macular oedema itself.

Effects of focal/grid laser treatment on the central visual field in diabetic macular oedema: a 2‐year follow‐up study

“…; Agardh et al. ), we found that CSMO was associated with very few, if any, significantly depressed points. The laser treatment reduced the thickness of the retina and lateral expansion of the oedema, but did not increase the number of depressed points.…”

Visual Dysfunction Associated with Diabetic Retinopathy

“…A study of human donor retinas demonstrated a 21% reduction of S-cones compared with medium-and long-wavelength cones [41]. SWAP has also been found to be abnormal in patients with DME, but the impairment appears to be caused by capillary damage rather than retinal thickening [42].…”

Quantification of Visual Field Loss in Age-Related Macular Degeneration

“…SWAP had a greater capability in detecting differences between the AMD groups and differences from normal, than SAP. Previous studies of blue-on-yellow perimetry in AMD [5], [6] did not compare results to SAP, however in patients with diabetes, sensitivity loss in the 10–2 visual field, due to structural change, was better detected by SWAP than SAP [23], [35], [36], [37]. The SWS pathway is vulnerable to a variety of retinal disease implying that SWS pathway sensitivity loss occurs at multiple sites of damage [38].…”