Evaluation of Nonperfused Retinal Vessels in Ischemic Retinopathy.
OBJECTIVE
Retinal ischemia has been traditionally assessed by fluorescein angiography, visualizing perfused vessels. However, this method does not provide any information about nonperfused vessels, and although it is often assumed that vessels in ischemic areas regress, we know little about how nonperfused retinal vessels change over time. Here, we aim to learn more about the long-term fate of nonperfused vessels in the retinal vasculature.


METHODS
Optical coherence tomography (OCT) was used to visualize perfusion as well as structural properties of the retinal vasculature in patients suffering from retinal vascular occlusions. In addition, postmortem tissue from a patient with long standing (6 years) central retinal vein occlusion (CRVO) was investigated, using immunohistochemistry on whole-mount retina and paraffin sections to visualize blood vessel components.


RESULTS
Comparing OCT angiography with enface OCT images revealed that in ischemic areas of the retina, nonperfused, larger vessels could be detected as hyperreflective structures in enface OCT images. Furthermore, analysis of a postmortem tissue sample from a CRVO patient with a large nonperfused region in the macula, revealed preservation of the basement membrane from all retinal vessels, including nonperfused, acellular vessels of all calibers.


CONCLUSIONS
Our data suggests long-term preservation of vascular basement membrane in ischemic retina. This has implications for therapeutic approaches aiming to alleviate retinal ischemia via the regeneration of damaged vessels.
UCL Institute of Ophthalmology, University College London, London, United Kingdom 2Division of Optometry and Visual Science, School of Health Sciences, City University London, London, United Kingdom.
Michael B
MB
Powner
UCL Institute of Ophthalmology, University College London, London, United Kingdom 3Moorfields Eye Hospital, London, United Kingdom.
Dawn A
DA
Sim
Save Sight Institute, University of Sydney, Sydney, Australia 5Lions New South Wales Eye Bank, Sydney and Sydney Eye Hospital, Sydney, Australia.
Meidong
M
Zhu
Moorfields Eye Hospital, London, United Kingdom.
João
J
Nobre-Cardoso
UCL Institute of Ophthalmology, University College London, London, United Kingdom.
Ryan
R
Jones
Save Sight Institute, University of Sydney, Sydney, Australia 6Sydney Institute of Vision Science, Sydney, Australia.
Adil
A
Syed
Save Sight Institute, University of Sydney, Sydney, Australia 6Sydney Institute of Vision Science, Sydney, Australia.
Andrew A
AA
Chang
UCL Institute of Ophthalmology, University College London, London, United Kingdom 3Moorfields Eye Hospital, London, United Kingdom.
Pearse A
PA
Keane
UCL Institute of Ophthalmology, University College London, London, United Kingdom 3Moorfields Eye Hospital, London, United Kingdom.
Adnan
A
Tufail
UCL Institute of Ophthalmology, University College London, London, United Kingdom 3Moorfields Eye Hospital, London, United Kingdom.
Catherine A
CA
Egan
UCL Institute of Ophthalmology, University College London, London, United Kingdom.
Marcus
M
Fruttiger