Iris angiography in ADAMTS10 mutant dogs with open‐angle glaucoma (ADAMTS10‐OAG)

Abstract

ObjectiveTo evaluate anterior segment angiographic findings in hypertensive ADAMTS10‐open‐angle glaucoma (ADAMTS10‐OAG) eyes as compared to normotensive control eyes.Animals StudiedNine ADAMTS10‐OAG beagles and four wild‐type control dogs.ProceduresAnterior segment angiography was performed under general anesthesia following intravenous injection of indocyanine green (ICG; 1 mg/kg) and sodium fluorescein (SF; 20 mg/kg) using a Heidelberg Spectralis® confocal scanning laser ophthalmoscope. Time to onset of iridal angiographic phases and the presence/severity of dye leakage into the iris stromal and/or aqueous humor were recorded. Group findings were compared, and multiple linear regression analysis was performed to identify potential factor associations with disease status.ResultsTime to onset of all angiographic phases visualized using ICG was significantly prolonged while time to onset of SF leakage into the aqueous humor was significantly reduced in glaucomatous eyes compared to controls. Only glaucomatous eyes (n = 9) demonstrated evidence of SF stromal leakage. Mean intraocular pressure (IOP) and age were significantly higher, while mean cardiac pulse was significantly lower in glaucomatous eyes compared to controls. Blood pressure and ocular perfusion pressure were not significantly different between groups. Multiple linear regression analysis, controlling for age, IOP, and pulse demonstrated glaucoma, was not predictive of the time to onset of any angiographic phase, stromal, or aqueous humor leakage. However, pulse was a significant factor contributing to the severity of aqueous humor leakage.ConclusionsA compromised vascular supply to the anterior segment exists in dogs with ADAMTS10‐OAG. These observations warrant further exploration of what role altered perfusion and/or disruption to the blood–aqueous barrier may play.

Role of Inflammation in Canine Primary Glaucoma

“…Canine eyes with primary glaucoma have compromised vascular integrity within the anterior uvea as a consequence of elevated IOP [ 1 , 11 ]. When compared to healthy controls, iris angiography of canine eyes with POAG had significantly prolonged times to onset of arterial, capillary, and venous phases, as well as slower onset but greater severity in fluorescein leakage within the aqueous humor [ 11 ].…”

“…Canine eyes with primary glaucoma have compromised vascular integrity within the anterior uvea as a consequence of elevated IOP [ 1 , 11 ]. When compared to healthy controls, iris angiography of canine eyes with POAG had significantly prolonged times to onset of arterial, capillary, and venous phases, as well as slower onset but greater severity in fluorescein leakage within the aqueous humor [ 11 ]. Such delayed perfusion and disruption to the blood–aqueous barrier may indicate pressure-associated anterior-segment ischemia (ASI) in dogs with primary glaucoma, as mentioned in a recent review by Drs.…”

“…In chronically affected POAG or PACG eyes, intraocular inflammation can result in peripheral anterior synechiae [ 11 , 13 , 14 ], preiridal fibrovascular membranes [ 1 , 13 , 15 , 16 ], and potential damage to trabecular meshwork cells [ 16 , 17 ].…”