Purpose
Post-mortem human retinal tissues are necessary for studies of macular disease. The lack of clinical information on eyes donated to research frequently limits the scope and accuracy in study of these tissues. Spectral Domain Optical Coherence Tomography (SD-OCT) has been previously used to screen post-mortem retinal changes including age-related macular degeneration (AMD). There are currently no known reports that correlate pre- and post-mortem macular anatomy using SD-OCT on the same eye. The purpose of this study was to describe the features of donated post-mortem retinas and correlate the findings with pre-mortem examination of the same eye using SD-OCT and scanning laser ophthalmoscopy.
Methods
Twelve donated eyes including AMD (n=8), diabetic macular edema (n=3) and normal control (n=1) were examined. All eyes were retrieved within 24 h of donor death. After corneal harvest for transplantation, eye cups were fixed in 4% Paraformaldehyde (PAF) for 72 hours before storage in 2% PAF. Prior to imaging, anterior segment was removed. Four trans-ora serrata sutures were placed to prevent retinal dialysis. During imaging, the eyes were mounted in a flat-topped glass jar filled with 0.9% NaCl or PBS to minimize optical distortions. A 30 diopter handheld indirect lens was used to replicate optical properties. Heidelberg SD-OCT and scanning laser ophthalmoscopy were performed with standard clinical protocols. Student t test was used to compare pre- and post-mortem foveal and macular thickness.
Results
Intra-retinal layers were clearly detected on post-mortem OCT scans. Pre-mortem pathological changes including pigment epithelial detachments, drusen, geographic atrophy and intra-retinal cysts were well correlated with post-mortem scans. Fixation-related retinal detachment and loss of sub-retinal fluid were identified in post-mortem images. Adjusting for the detachment, higher foveal thickness (FT) and central macular thickness (CMT) were noted in post-mortem scans compared with pre-mortem images (FT 247.6μm vs.165.8μm, p=0.23; CMT: 387.8μm vs. 229.0μm, p=0.01).
Conclusions
SD-OCT can effectively image fixed post-mortem retinal tissues. Correlation of pre- and post OCT images as well as multicolor fundus imaging may potentially add significant morphological information to the post-mortem retinal research.