Abstract
Abstract: :
Purpose:To investigate the role of pigment dispersion and acute inflammation in the pathogenesis of breed–related goniodysgenesis associated glaucoma. Methods:Records from 2,905 pathology submissions from dogs with glaucoma were reviewed. Cases with a diagnosis of goniodysgenesis were selected only when the duration of the disease was specified. Cases were subdivided into breeds, and only breeds having more than three samples were included in the study. The total number of cases included was 100. Slides were evaluated for the following: presence of pigment cells in the trabecular meshwork; the ability to identify the dependent side of the eye based on the distribution of pigment; the segmental absence of pigment epithelial cells from the posterior iris; evidence of stripping of pigmented cells from the posterior iris epithelium; and free pigmented cells in the iridocorneal angle. Globes were evaluated further for the presence or absence of inflammatory cell infiltration in the trabecular meshwork. Neutrophilic and lymphoplasmacytic infiltration was quantified independently. Changes were compared at different intervals from the clinical onset of disease. Results:Of 100 cases evaluated, there were 62 Cocker Spaniels, 14 Bassett Hounds, 10 Labrador Retrievers , 7 Chow Chows and 7 Huskies. Sex distribution was approximately 2 females to 1 male. 14 were 0–3d in duration, 20 were 4–7d and 66 were >7d. 93% of 0–3d glaucomas and 95% of 4–7d glaucomas had free pigment. 79% of >7d cases had free pigment. 43% of 0–3d, 75% of 4–7d and 55% of >7d glaucomas had pigment epithelium missing from the posterior iris surface. 21% of 0–3d, 45% of 4–7d, and 21% of >7d cases had evidence of cell stripping from the posterior iris surface. 64% of 0–3d, 95% of 4–7d, and 50% of >7d had pigmented cells in the iridocorneal angle. 86% of 0–3d, 50% of 4–7d, and 14% of >7d glaucomas had neutrophils. 64% of 0–3d, 80% of 4–7d, and 48% of >7d cases had lymphoplasmacytic inflammation. 57% of 0–3d, 35% of 4–7d and 12% of >7d cases had evidence of both types of inflammation. Conclusions:Both acute inflammation and pigment dispersion are more likely to be seen within the first three days from the onset of clinical disease. The correlation is much stronger for neutrophilic inflammation. Lymphoplasmacytic inflammation was not seen more frequently in acute glaucoma. The finding of iris pigment epithelial loss or stripping away of the iris epithelium supports the theory that pupillary block associated with touching of the parapupillary iris to the lens is important in the pathogenesis of canine glaucoma associated with goniodysgenesis.
Keywords: pathobiology • inflammation • microscopy: light/fluorescence/immunohistochemistry