Orlando, Fla. (May 6, 2014) — A new study from the Lions Eye Institute for Transplant & Research (LEITR) and the Eye Institute at the University of South Florida (USF) demonstrates that commonly used clinical techniques to image the anterior segment of the eye can be adapted to screen the posterior segment of postmortem eyes for preclinical research.
Investigators employed high frequency ultrasound to successfully image retinal structures in postmortem eyes. This additional technique can be used to screen postmortem eyes for disease-specific conditions. The findings were presented today at the 2014 Association for Research in Vision and Ophthalmology (ARVO) Annual Meeting.
“One of our goals at LEITR is to provide researchers with fresh, disease-specific ocular tissue that is best suited to their research efforts,” says Mitchell D. McCartney, Ph.D., Scientific Director, Lions Eye Institute for Transplant & Research. “The study findings demonstrate that new clinical imaging technologies such as UBM and OCT can be used postmortem to identify early stage eye disease and provide near-clinical histories of donors, maximizing the opportunity to utilize the tissue for critical ocular research.”
“With the aid of the UBM probe and OCT microscope, researchers can be more confident of a donor’s medical history and whether or not he or she had any retinal diseases,” says Peter R. Pavan, M.D., Professor and Chair, University of South Florida Eye Institute. “The more information that is known about the donor, the more validated the study results will be.”
About the Study
Postmortem globes procured by LEITR in Tampa, FL were enucleated by standard techniques and transported to USF Eye Institute laboratory in saline soaked gauze moist chamber on ice. Within 12 hours post mortem, the eyes received topical drops of 10 percent phelylephrine and 1 percent tropicamide, given in two rounds, three minutes apart. Investigators oriented and secured the globes with the corneas facing forward and, using a 32-gauge needle, injected a balanced salt solution into the vitreous cavity through a 4 mm site posterior to the limbus. Optical coherence tomography (OCT) raster line scanning images of the macula were obtained.
The eyes were then reoriented so that the posterior pole was facing forward. A high frequency (40 mHz) ultrasound biomicroscopy (UBM) probe covered with a water-filled ultrasound transducer cover was placed over the back of the eyes to obtain images of the macula and adjacent retina. Similar to previous studies1, the results show the pharmacologic agents increased the pupil diameter an average of 1.87 mm. OCT imaging of the macula identified much of the anatomy seen in an in vivo scan, although postmortem retinal changes imposed some limitations.
The UBM showed recognizable retinal landmarks in the posterior pole and correlated well with the pathology seen on the OCT images such as the epiretinal membranes causing macular puckering. Source: Pavan PR, McCartney MD, Saunders T, Gore P, Sprehe N, Saxan W, Margo CE, “Postmortem Ultrasound and OCT Imaging of the Posterior Segment.” Poster presented May 6, 2014 at the 2014 Association for Research in Vision and Ophthalmology (ARVO) Annual Meeting.
About the Lions Eye Institute for Transplant & Research (LEITR)
The Lions Eye Institute for Transplant & Research, Inc., (LEITR) is a nonprofit organization dedicated to the recovery, evaluation and distribution of eye tissue for transplantation, research and education. LEITR, located in Tampa, FL, is the only combined eye bank and ocular research center in the world. Since its inception, it has brought the “Gift of Sight” to more than 55,000 men, women and children worldwide. For more information, visit www.lionseyeinstitute.org.
References:
1. Golen JR, Saunder T, Sprehe N, Gore P, Malavade SS, Pavan PR, Margo CE, “Can Meaningful Pharmacological Dilation of Pupils Occur After Death?” Presented May 6, 2013 at the 2013 Association for Research in Vision and Ophthalmology (ARVO) Annual Meeting