Abstract
Purpose: :
To evaluate the characteristics of retinal fixation in patients with clinically significant diabetic macular edema (CSME) using microperimetry
Methods: :
One hundred forty seven eyes from 75 patients with untreated CSME underwent visual acuity measurement with a standard Early Treatment Diabetic Retinopathy Study (ETDRS) procedure. Digital color stereoscopic fundus photos and fluorescein angiography (FA) were carried out by a certified photographer ( TOPCON TRC 50IA, Topcon, Tokyo, Japan) angiographer . Retinal thickness and intraretinal structure were assessed with Stratus OCT TM scanner (Zeiss Humphrey Instruments, Germany). Fixation and retinal thresholds were determined and classified with the automatic microperimeter (MP1, Nidek Technologies, Padova, Italy).
Results: :
Fixation was central in 99 (67.4%), poor central in 24 (16.3%) and predominantly eccentric in 24 (16.3%) eyes; stable in 106 (72.1%), relatively unstable in 37 (25.2%) and unstable in 4 (2.7%) eyes. Fixation location and stability were not significantly influenced by the characteristics of edema (diffuse, focal, cystoid, with or withouth subfoveal neuroretinal detachment), (p>0.05, both), whereas they were significantly influenced by the presence of subfoveal hard exudates, (p=0.004 and p=0.0046, respectively). There was a significant association between site and stability of fixation, (Fisher’s exact test, p<0.0001). The location of retinal pseudofovea would have been covered by laser photocoagulation in 47% of eyes with poorly central and predominantly eccentric fixation and in 63% of eyes with relatively unstable and unstable fixation.
Conclusions: :
Microperimetry shows that fixation location and stability in patients with CSME is preserved regardless of the characteristics of edema, except when subfoveal hard exudates are present. Location of pseudofovea may influence treatment strategy.
Keywords: diabetic retinopathy • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • perimetry