title: Morphological Abnormalities of Schlemm's Canal in Primary Open-Angle Glaucoma From the Aspect of Aging.
abstract: OBJECTIVE
  To evaluate morphological abnormalities of Schlemm's canal (SC) among primary open-angle glaucoma (POAG) patients with a family history of POAG (group A), those without a family history of POAG (group B), and patients with normal-tension glaucoma (group C) from the aspect of aging.
  
  
  METHODS
  A total of 160 trabeculectomy specimens from 133 POAG patients were processed for light microscopy using immunohistochemical staining of thrombomodulin and transmission electron microscopy. The following parameters were statistically evaluated: SC length, the percentage of the thrombomodulin-negative area (PTNA) of SC, and the inner-wall SC endothelial cell density (SC-ECD/100 μm).
  
  
  RESULTS
  No significant differences in age were observed among the three groups (group A: 56.71 ± 14.83; group B: 58.13 ± 18.13; group C: 56.61 ± 9.78). Length of SC in the group A patients (198.70 ± 81.65 μm, n = 70 eyes) was significantly shorter than in group B (250.30 ± 70.83 μm, n = 67 eyes), and group C (277.70 ± 65.52 μm, n = 23 eyes) patients. A positive correlation of patient age and SC length was observed in group B (r = 0.45, P = 0.0013), but SC length in group A tended to decrease with aging (r = -0.22, P = 0.07). No significant difference in SC was found between group A and B patients before age 50 years (P = 0.30). Correlations between patient age and increase of PTNA (r = 0.38, P = 0.0013) and patient age and decrease of SC-ECD (r = -0.53, P = 3.95 × 10(-6)) were observed only in the group B cases.
  
  
  CONCLUSIONS
  Our findings suggest that SC in group A may easily collapse during middle age, while SC in group B remains open and SC endothelial cells drop out at around middle age.
authors.affiliation: Department of Ophthalmology Japanese Red Cross Medical Center, Tokyo, Japan.
authors.forename: Teruhiko
authors.initials: T
authors.lastname: Hamanaka
authors.affiliation: Laboratory of Ocular Atopic Diseases, Department of Ophthalmology, Juntendo University, Tokyo, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Matsuda
authors.affiliation: Department of Center of General Education, Tokyo University of Science, Suwa, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Sakurai
authors.affiliation: Department of Pathology, Japanese Red Cross Medical Center, Tokyo, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Kumasaka
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D002452:Cell Count; D018450:Disease Progression; D004727:Endothelium / Q000648:ultrastructure; D005260:Female; D005500:Follow-Up Studies; D005902:Glaucoma, Open-Angle / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D008297:Male; D046529:Microscopy, Electron, Transmission; D008875:Middle Aged; D012189:Retrospective Studies; D014129:Trabecular Meshwork / Q000648:ultrastructure*; D014130:Trabeculectomy; D055815:Young Adult