Abstract
Purpose :
To assess the overall visual function losses in eyes with age-related macular degeneration (AMD) compared to normal controls and to correlate the pathological structural changes associated with AMD on optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) with microperimetry (MP).
Methods :
This was a prospective, observational study that involved 10 eyes with intermediate to advanced AMD and visual acuity worse than 6/15 compared to the right eye of 10 normal controls without disease recruited from a single tertiary center. OCT, OCTA and microperimetry were performed for all eyes. OCT and OCTA were graded for pathological lesions by 2 independent graders. A standardized algorithm was designed to superimpose enface OCT and OCTA images on MP fundus images, to correlate pathological structural changes to zonal functional changes detected on MP such as mean retinal sensitivity (MRS), fixation area and stability.
Results :
The mean age and gender of AMD patients compared to controls were 66.2 versus 70.9 years (p=0.21), 60% versus 20% male. The MRS of eyes with AMD was significantly worse than in normal controls (21.1db; SD=2.8 versus 25.9dB; SD=7.5 (p<0.0001)). The majority of eyes with AMD (70%) had unstable fixation, compared to normal eyes with only 1(10%) with unstable fixation (p<0.05). In the first test case, visual acuity (VA) 6/18 (Figure 1), the area of drusen (Figure 1) had MRS of 14.7dB (SD=3.3) that was similar to the surrounding retina (MRS=14.4dB; SD=3.1) (p=0.85). In second test case, VA 6/18 (Figure 2), retinal sensitivities were not able to be determined however, the fixation was centred on the area of subretinal fibrosis. Detailed structural and functional correlated results of a larger cohort are currently being analysed and will be presented.
Conclusions :
Eyes with advanced AMD have a significantly worse overall visual function as measured by lower MRS and more unstable fixation. Instead of using only VA as a measure of visual function, by studying how specific pathological changes seen on OCT/OCTA affect the visual function of the individual patient, we are able to differentiate structural changes associated with a poorer visual function. A detailed study of visual function provides an added outcome measure that may help guide treatment and accurately predict long term prognosis in eyes with advanced AMD.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.