Aim To estimate the prevalence, causes and risk factors for presenting distance and near vision impairment (VI) in Trinidad and Tobago.
Methods This is a national, population-based survey using multistage, cluster random sampling in 120 clusters with probability-proportionate-to-size methods. Stage 1 included standardised, community-based measurement of visual acuity. Stage 2 invited all 4263 people aged ≥40 years for comprehensive clinic-based assessment. The Moorfields Eye Hospital Reading Centre graded fundus photographs and optical coherence tomography images independently.
Results The response rates were 84.2% (n=3589) (stage 1) and 65.4% (n=2790) (stage 2), including 97.1% with VI. The mean age was 57.2 (SD 11.9) years, 54.5% were female, 42.6% were of African descent and 39.0% were of South Asian descent. 11.88% (95% CI 10.88 to 12.97, n=468) had distance VI (logarithm of the minimum angle of resolution [logMAR] >0.30), including blindness (logMAR >1.30) in 0.73% (95% CI 0.48 to 0.97, n=31), after adjustment for study design, non-response, age, sex and municipality. The leading causes of blindness included glaucoma (31.7%, 95% CI 18.7 to 44.8), cataract (28.8%, 95% CI 12.6 to 45.1) and diabetic retinopathy (19.1%, 95% CI 4.2 to 34.0). The leading cause of distance VI was uncorrected refractive error (47.4%, 95% CI 43.4 to 51.3). Potentially avoidable VI accounted for 86.1% (95% CI 82.88 to 88.81), an estimated 176 323 cases in the national population aged ≥40 years. 22.3% (95% CI 20.7 to 23.8, n=695) had uncorrected near VI (logMAR >0.30 at 40 cm with distance acuity <0.30). Significant independent associations with distance VI included increasing age, diagnosed diabetes and unemployment. Significant independent associations with near VI included male sex, no health insurance and unemployment.
Conclusions Trinidad and Tobago’s burden of avoidable VI exceeds that of other high-income countries. Population and health system priorities are identified to help close the gap.
- public health
- optics and refraction
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Collaborators Scientific Advisors: Prof R Allingham, Dr H Bailey, Prof C Carrington, Ms T Crowley, Prof A Gray, Prof M Hauser, Ms M Hingorani, Prof A Hingorani, Prof J Pablo-Casas, Prof S Pardhan, Prof K Pesudovs, Mr K McNally, Ms W Newsom, Dr A Roach, Dr A Sharma, Dr R Sharma, Dr V Tripathi, Prof S Teelucksingh.
Data collection: Ms K Badal, Mr R Ballah, Ms C Bridgemohan, Mr M Bruce, Ms K Carter, Ms A Cesair, Mr T Crowley, Ms A Fraser, Ms N Lynch, Ms V Maharaj, Ms E Marcellin, Mr M Narine, Ms A Pascall, Ms M Persad, Ms B Pulchan, Ms L Robinson. Deceased: Scientific Advisor, Professor Rand Allingham.
Contributors Conception and design of study: TB, NQV, TP, PB, SS, DS, SSR, RRAB. Acquisition of data: TB, DB, FD, PB. Analysis and/or interpretation of data: TB, NQV, AS, TP. Drafting the manuscript: TB. Revising the manuscript critically for important intellectual content: TB, NVQ, AS, TP, PB, SS, DS, SSR, RRAB, DB, FD. Approval of the final version: TB, NVQ, AS, TP, PB, SS, DS, SSR, RRAB, DB, FD, on behalf of the NESTT Study Group.
Funding The study was funded by the Ministry of Health of the Government of Trinidad and Tobago and Fight for Sight UK (Grant ref 1339/40). The sponsor or funding organisation had no role in the design or conduct of this research.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval We obtained ethics committee approval from the Ministry of Health of the Government of the Republic of Trinidad and Tobago, the University of the West Indies (Trinidad) and Anglia Ruskin University (UK). The study adhered to the tenets of the Declaration of Helsinki.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Further analyses on the unpublished data set are in progress with manuscripts in preparation. Data access is governed by the NESTT Steering Committee, chaired by a representative of the Faculty of Medical Science at the University of the West Indies (St Augustine, Trinidad) and academic partners in the Vision and Eye Research Unit at Anglia Ruskin University (Cambridge, UK).