Pattern of Presentation and Outcome of Surgical Management of Primary Open Angle Glaucoma in Kano, Northern Nigeria

Abstract

Background: Primary open angle glaucoma (POAG) is one of the leading causes of avoidable blindness. Unlike blindness from cataracts, glaucomatous optic nerve damage is irreversible, and prevention of
glaucoma is one of the priorities of World Health Organization (WHO) Vision 2020 program. POAG is the commonest type of glaucoma and affects about 33.1 million people worldwide. This study is a five
year review of 71 eyes of 63 patients who had trabeculectomy. The study evaluates the pattern of presentation and modality of surgical treatment in our environment.
Methods: Records of all patients with primary open angle glaucoma operated over a five year period was retrieved. Information extracted included patients bio data, visual acuity, gonioscopic findings, intra
ocular pressure as measured with applanation tonometer before and after surgery, and recorded in mmHg. Perimetry was done with 2 m tangent screen and recorded in a perimetry chart. All the patients
had trabeculectomy with application of anti metabolite (5fluorouracil). Extra capsular cataract extraction with or, without posterior chamber intra ocular lens implantation was done on 13 patients. Biometry was
not done on patients with cataract. Surgery was done on better eye first in all patients.

Results: There were 71 eyes of 63 patients. The male to female ratio was 3:1. The age ranged between 18 to 75 years. 8 patients were below the age of 30 years. One third of the patients were between the ages of
50 to 59 years. At presentation 12 patients (19%) had normal vision (WHO vision category O), 26 patients (41%) were visually impaired, 12 patients (19%) were severely visually impaired and 13 patients
(21%) were blind (from co existing cataracts). The cup disc(c: d) ratio assessed before surgery was 0.5 in 9 eyes (13%), 31 eyes (53%) had c: d ratio 0.6 to 0.8 and 18 eyes had c: d ratio of 0.9. All the patients
had open anterior chamber angles (Schafer grade 3 and 4). Perimetric changes were; mild peripheral constriction in 5 eyes (8%), peripheral constriction with arcuate scotoma in 19 eyes (26%), constricted
fields of 30° or less in 34 eyes (48%), and in 13 eyes there was inability to fixate on target. IOP before surgery was 21 to 30 mm Hg in 12 eyes (17%), and above 31 mm Hg in 69 eyes (83%). Post operative
IOP of 10 to 15 mm Hg was obtained in 58 eyes (82%) and 11 eyes (15%) had IOP of 16 to 20 mm Hg. Only 2 eyes (3%) had IOP in the lower twenties.

Conclusion: Primary open angle glaucoma is characterized by late presentation. Trabeculectomy with application of 5FU is the surgical treatment of choice in our environment and give good intra ocular
pressure control. There is need to increase public awareness on glaucoma to limit this type of avoidable blindness