Purpose:
To compare the clinical findings and morphological differences of Schemm’s canal (SC) in trabeculectomy (TLE) specimens of eyes with primary open angle glaucoma (POAG, IOP >21mmHg) between patients with a family history (group A) and those without a family history of POAG (IOP >21mmHg) or ocular hypertension (OH) (group B).
Methods:
Thirty patients in each group were questioned about the family history of glaucoma in the routine post-operative examination and retrospectively reviewed for age at TLE, visual field (Aurhorn-Greve cassfication), cup/disc ratio, maximum pre-operative IOP, and spherical equivalent power. All affected family members with glaucoma in group A were examined for whether they had normal tension glaucoma, angle closure glaucoma, pseudoexfoliation or other types of secondary glaucoma. Patients who have other than POAG (IOP >21mmHg) or OH in the family history were excluded from this study. Seventy-four TLE specimens (40 eyes in group A, and 34 eyes in group B) of 30 patients in each group were embedded in paraffin and processed for immunohistochemical staining of thrombomodulin to detect the endothelium of SC, and the meridional length of SC was measured.
Results:
Maximum pre-operative IOP, spherical equivalent power and the length of SC showed a significant difference between the two groups (Table). The thrombomodulin staining pattern of SC in most of the eyes in group A tended to be very strong and was similar to that of Sondermann’s canal.
Conclusions:
Higher myopia and IOP in the eyes of group A suggested that POAG may have occurred at a younger age. The developmental abnormality of SC may be very important for causing POAG in hereditary POAG.
Keywords: outflow: trabecular meshwork • development • pathology: human