Glaucoma screening in Western Cameroon.

ABSTRACT

PURPOSE: To quantify glaucoma-related parameters in a rural African region. MATERIAL AND METHOD: In a population-based investigation, 635 persons in six villages underwent slit-lamp examination including investigation of the optic nerve head with a 90D lens and Goldmann applanation tonometry. The mean age of the persons was 49.4 +/- 19 years, minimum 5, maximum 90, median 52 years. The inferior, superior, nasal and temporal margin width of the optic nerve head (ONH) were estimated as fractions of the total disk diameter, thus allowing the evaluation of the horizontal and vertical cup-disk ratio (CDR), the ratio of the elliptical cup area to the total disk area (area CDR), and violations of the ISNT rule (Inferior>or=Superior>or=Nasal>or=Temporal ONH rim). RESULTS: Area CDR significantly increased with age, on average from 0.1 in the youngest to 0.47 in the oldest person, corresponding to an increase of linear CDR from 0.32 to 0.68. The total fraction of eyes exceeding an area CDR of 0.5 (i.e. linear 0.7) was 13.4%. In addition, the intraocular pressure (IOP) increased on average from 14 mmHg in the youngest to 20 mmHg in the oldest persons, but nevertheless many high CDR values were found in eyes with normal to moderately elevated IOP. Violations of the ISNT rule were found in approximately 25% of the eyes. Application of a combination of glaucoma criteria as commonly used in literature resulted in a total prevalence of 18.7% of the screened persons, corresponding to a prevalence of 8.2% after age correction for the--on average--very young Cameroonian population. CONCLUSION: Compared to Europe, glaucoma prevalence appears to be nearly an order of magnitude higher in this rural African population.