Abstract
Purpose: :
To assess the presence of premacular vitreous (PV) modifications in patients affected by non-exudative age-related macular degeneration (AMD) using high-resolution spectral domain (SD) - OCT
Methods: :
106 eyes of 53 patients with non-exudative AMD, mean age 75.74 ± 6.93 years, 36F and 17M, were studied. 53 eyes randomly selected in 53 healthy, age-matched, subjects were used as control eyes (CEs). All subjects had ametropia < 3D and underwent clinical examination including visual acuity evaluation using ETDRS chart and slit-lamp biomicroscopy with +90 D lens; in AMD patients fluorescein angiography was also performed. The macular morphology and the PV were studied with a SD - OCT Cirrus (Carl Zeiss Meditec, Inc Dublin, CA) using Macular Cube 512x128 test and high resolution 6 and 9 mm B-scans (HD line raster scan). The differences observed between groups were evaluated by 2-by-2 tables and chi-square test. Values are expressed as means ± 1 standard deviation. A level of p<0.05 was accepted as statistically significant.
Results: :
Prevalence of PV modifications was significantly higher in non-exudative AMD eyes compared to CEs: PV modifications were found in 49 of the 106 AMD eyes (46.2%) and in 10 of the 53 (18.8%) CEs (P=0.001). Modifications in CEs consisted in the presence of a premacular pocket filled with liquefied vitreous (PVP). The AMD eyes were divided into 4 groups according to the PV modifications detected by OCT: Group 1, no vitreous modifications (NVM); Group 2, presence of PVP; Group 3, presence of epiretinal membrane (ERM); Group 4, vitreo-macular traction (VMT). The prevalences of the different kinds of PV modifications for each group were as following: NVM 57/106 (53.7%), PVP 12/106 (11,3%), ERM 31/106 (29.2%) and VMT 6/106 (5.6%). PV modifications were found in 30 patients and were bilateral in 20 patients (66.6%), (P=0.02).
Conclusions: :
The presence of PV modifications even in non-exudative AMD supports the hypothesis of a correlation between external retina and premacular vitreous. PV modifications could be due to metabolic damages, leading to macular cells death and impairment of the internal limiting membrane (ILM) of Mueller cells, or to pathological changes occurring in degenerative age-related diseases that can compromise both retinal pigmented epithelium and adhesion between posterior vitreous cortex and ILM.
Keywords: age-related macular degeneration • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • vitreous