Rapid Assessment of Avoidable Blindness in Son La Province, Viet Nam: Gender Differences

1. Anna-Lena Arnold¹
2. Dr Tran Huy Hoang²
3. Dr Dzung³
4. Dr Lucy Busija¹
5. Gail Ormsby⁴
6. Professor Jill Keeffe¹

¹Centre for Eye Research Australia, The University of Melbourne, The Royal Victorian Eye and Ear Hospital, Melbourne Vic, Australia
²Ho Chi Minh Eye Hospital, Ho Chi Minh, Viet Nam
³Vietnam Institute of Ophthalmology, Hanoi, Viet Nam
⁴CBM Australia and Vietnam

Purpose: To estimate the prevalence and causes of vision loss in people aged ≥50 years of age in 6 districts of Son La province and examine differences in socio-economic status and by gender.

Methods: Sixty three clusters of 50 people aged ≥50 years were selected. Households were selected by compact segment sampling. All participants underwent a standardized ophthalmic examination: visual acuity (VA) was assessed using a tumbling E chart. The lens status and cause of vision loss were assessed using direct ophthalmoscopy. The pupil was dilated where necessary.

Results: A response rate of 97.6% (3070/3146) was achieved. The age and sex adjusted prevalence of blindness (presenting VA <3/60 in the better eye) was 1.7% and 8.3% for vision impairment (presenting VA <6/18-3/60 in the better eye). A higher proportion of women were blind compared to men (2.1% vs 1.1%, OR 2.13 CI 1.17-3.88) and a higher proportion of women were vision impaired compared to men (9.7% vs 6.8%, OR 1.49 CI 1.15-1.94).
The causes of blindness were un-operated cataract (55.6%), glaucoma (8.9%), uncorrected aphakia (6.7%), corneal scar (4.4%), phthisis (2.2%), other (22.2%). The principal causes of vision impairment were uncorrected refractive error (54.9%), un-operated cataract (28.1%), surgical complications (3.4%), AMD (1.7), corneal scar (0.9%), diabetic retinopathy (0.9%), uncorrected aphakia (0.4%), trachoma (0.1%), other (9.4%).

Conclusion: Our results indicate there is a higher prevalence of vision loss for the women surveyed across the 6 districts of Son La province. Eighty five percent (238/280) of the causes of vision loss are avoidable.