METHODS: Diurnal variation of intraocular pressure was measured in 202 eyes of suspected open-angle glaucoma patients and 100 control eyes, at 4-hourly intervals for 24 hours (phasing). Based on the phasing results, optic disc changes and visual field defects, the patients were diagnosed as primary open angle glaucoma (POAG), normal tension glaucoma (NTG), ocular hypertension (OHT), or physiologic cup (PC), or still remained as glaucoma suspects due to inconclusive diagnosis. The last group (glaucoma suspects) was then followed up 6-monthly for their eventual outcome.
RESULTS: The highest percentage of suspected glaucoma patients had peak (maximum) readings in the mid-morning (10-11 A.M.) and trough (minimum) readings after midnight (2-3 A.M.); the highest percentage of control group had peak readings in the late evening (6-7 P.M.) and trough readings after midnight (2-3 A.M.). The mean amplitude of variance was 6 mm Hg in suspected glaucoma group and 4 mm Hg in the control group. After 'phasing', 18.8% of the suspected glaucoma patients were diagnosed as POAG, 16.8% as NTG, 5% as OHT, and 28.7% as physiologic cup; 30.9% remained as glaucoma suspects. After 4 years follow-up, 70% of the glaucoma suspects still remained as glaucoma suspects, 6.7% developed NTG and another 6.7% POAG; 16.6% were normal.
CONCLUSIONS: Serial measurement of IOP ( phasing) in a 24-hour period is still needed, in order not to miss the peak and the trough IOP readings in suspected open-angle glaucoma patients, which helps in better management of glaucoma. Among 30.9% of patients who remained as glaucoma suspects after the initial phasing, 13.4% developed NTG/POAG over a period of 4 years.
METHODS: A stratified two stage cluster sampling design was used to randomly select primary and secondary sampling units. Interviews, visual acuity tests, and eye examinations on all individuals in the sampled households were performed. Estimates were weighted by factors adjusting for selection probability, non-response, and sampling coverage.
RESULTS: The overall response rate was 69% (that is, living quarters response rate was 72.8% and household response rate was 95.1%). The age adjusted prevalence of bilateral blindness and low vision was 0.29% (95% CI 0.19 to 0.39%), and 2.44% (95% CI 2.18 to 2.69%) respectively. Females had a higher age adjusted prevalence of low vision compared to males. There was no significant difference in the prevalence of bilateral low vision and blindness among the four ethnic groups, and urban and rural residents. Cataract was the leading cause of blindness (39%) followed by retinal diseases (24%). Uncorrected refractive errors (48%) and cataract (36%) were the major causes of low vision.
CONCLUSION: Malaysia has blindness and visual impairment rates that are comparable with other countries in the South East Asia region. However, cataract and uncorrected refractive errors, though readily treatable, are still the leading causes of blindness, suggesting the need for an evaluation on accessibility and availability of eye care services and barriers to eye care utilisation in the country.