Relationship of the change of macular thickness and microstructure with visual acuity in eye with idiopathic epiretinal membrane / 中华实验眼科杂志

ABSTRACT

Background Traction of epiretinal membrane results in macular morphologic change and visual functional impairment in eye with idiopathic epiretinal membrane (IERM),therefore figuring out their relationship is helpful for evaluation of disease prognosis.Objective This study was to observe the morphological change of macula and microstructure,and analyze the relationship between retina thickness,integrity of cone outer segment tips (COST) line in fovea and visual acuity.Methods This was a retrospective case-observational study.Fifty-six consecutive cases diagnosed as IERM in Zhongshan Ophthalmic Center from March 2011 to December 2011 were enrolled in this study,and all the patients showed unilateral IERM with the normal fellow eyes.Sixteen patients were males and 40 were females,with a mean age of (61.05 ± 6.58) years old.Spectral-domain optical coherence tomography (SD-OCT) examination was performed on the eyes,and Macular Cube (512×128) and HD 5 Line program were selected.Mean retinal thickness of central area (＜1 mm diameter),inner ring area (1-3 mm diameter) and outer ring area (＞3-6 mm diameter) of macula and the status of COST line (intact or fractured) was recorded.Mean thickness of whole macular areas and the difference of foveal microstructure were compared,and the correlation between retinal thickness and visual acuity was analyzed using Pearson linear correlation analysis.Related parameters including age,visual acuity,retinal thickness were also compared between the continuous COST lines group and the fractured COST lines group by independent sample t test.Results The flatted or disappeared fovea was seen in IERM eyes on the SD-OCT image.Retinal thicknesses were (446±89)μm,(418±64)μm and (328±34)ttm in the central area,inner ring area and outer ring area of macula in the IERM eyes,exhibiting significant increasing in comparison with (250±22) μm,(319±17) μm and (279±17) μm in the normal fellow eyes (t=13.370,9.523,7.769,all P =0.000).Significantly negative correlations were found between the visual acuity and the central macular thickness,inner ring thickness or outer ring thickness (r=-0.686,-0.653,-0.417,P＜0.05).In the IERM eyes,COST band was intact in 20 eyes and lack in 36 eyes.Compared with COST band intact group,aging,worse vision and increased retinal thickness were seen in the COST band absent group (t =2.109,P =0.039 ; t =-4.093,P =0.000 ; t =6.669,P=0.000;t=5.376,P=0.000;t=4.247,P=0.000).COST band was clear in all the normal fellow eyes on the SD-OCT image.Conclusions Increase of macular thickness and disruption of COST band reflect the visual function damage in IERM eye.Deficiency of COST band on OCT image seems to be an early indication of photoreceptor damage.Incomplete fovea COST band is often seen in older patients.