Sight impairment registration in Trinidad: trend in causes and population coverage in comparison to the National Eye Survey of Trinidad and Tobago.

BACKGROUND: Little was known about the population coverage and causes of sight impairment (SI) registration within the Caribbean, or the extent to which register studies offer insights into population eye health. METHODS: We compared causes of SI registration in the Trinidad and Tobago Blind Welfare Association (TTBWA) register with findings from the 2014 National Eye Survey of Trinidad and Tobago (NESTT), and estimated registration coverage. Cross-sectional validation studies of registered clients included interviews, visual function and cause ascertainment in July 2013, and interviews and visual function in July 2016. RESULTS: The TTBWA register included 863 people (all ages, 48.1%(n = 415) male) registered between 1951 and 2015. The NESTT identified 1.1%(75/7158) people aged ≥5years eligible for partial or severe SI registration, of whom 49.3%(n = 37) were male. Registration coverage was approximately 7% of the eligible population of Trinidad. Nevertheless, there was close agreement in the causes of SI comparing the register and population-representative survey. Glaucoma was the leading cause in both the register (26.1%,n = 225) and population-based survey (26.1%, 18/69 adults), followed by cataract and diabetic retinopathy. In the validation studies combined, 62.6%(93/151) clients had severe SI, 28.5%(43/151) had partial SI and 9.9%(15/151) did not meet SI eligibility criteria. SI was potentially avoidable in at least 58%(n = 36/62) adults and 50%(n = 7/14) children. CONCLUSION: We report very low register coverage of the SI population, but close agreement in causes of SI to a contemporaneous national population-based eye survey, half of which resulted from preventable or treatable eye disease.

National Eye Survey of Trinidad and Tobago (NESTT): prevalence, causes and risk factors for presenting vision impairment in adults over 40 years.

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.

Health system dynamics analysis of eyecare services in Trinidad and Tobago and progress towards Vision 2020 Goals.

Avoidable blindness is an important global public health concern. This study aimed to assess Trinidad and Tobago's progress towards achieving the Pan American Health Organization, 'Strategic Framework for Vision 2020: The Right to Sight-Caribbean Region,' indicators through comprehensive review of the eyecare system, in order to facilitate health system priority setting. We administered structured surveys to six stakeholder groups, including eyecare providers, patients and older adult participants in the National Eye Survey of Trinidad and Tobago. We reviewed reports, registers and policy documents, and used a health system dynamics framework to synthesize data. In 2014, the population of 1.3 million were served by a pluralistic eyecare system, which had achieved 14 out of 27 Strategic Framework indicators. The Government provided free primary, secondary and emergency eyecare services, through 108 health centres and 5 hospitals (0.26 ophthalmologists and 1.32 ophthalmologists-in-training per 50 000 population). Private sector optometrists (4.37 per 50 000 population), and ophthalmologists (0.93 per 50 000 population) provided 80% of all eyecare. Only 19.3% of the adult population had private health insurance, revealing significant out-of-pocket expenditure. We identified potential weaknesses in the eyecare system where investment might reduce avoidable blindness. These included a need for more ophthalmic equipment and maintenance in the public sector, national screening programmes for diabetic retinopathy, retinopathy of prematurity and neonatal eye defects, and pathways to ensure timely and equitable access to subspecialized surgery. Eyecare for older adults was responsible for an estimated 9.5% (US$22.6 million) of annual health expenditure. This study used the health system dynamics framework and new data to identify priorities for eyecare system strengthening. We recommend this approach for exploring potential health system barriers to addressing avoidable blindness, and other important public health problems.

The National Eye Survey of Trinidad and Tobago (NESTT): Rationale, Objectives and Methodology.

PURPOSE: This paper describes the rationale, study design and procedures of the National Eye Survey of Trinidad and Tobago (NESTT). The main objective of this survey is to obtain prevalence estimates of vision impairment and blindness for planning and policy development. METHODS: A population-based, cross-sectional survey was undertaken using random multistage cluster sampling, with probability-proportionate-to-size methods. Eligible participants aged 5 years and older were sampled from the non-institutional population in each of 120 cluster segments. Presenting distance and near visual acuity were screened in their communities. People aged 40 years and older, and selected younger people, were invited for comprehensive clinic assessment. The interview included information on potential risk factors for vision loss, associated costs and quality of life. The examination included measurement of anthropometrics, blood glucose, refraction, ocular biometry, corneal hysteresis, and detailed assessment of the anterior and posterior segments, with photography and optical coherence tomography imaging. Adult participants were invited to donate saliva samples for DNA extraction and storage. RESULTS: The fieldwork was conducted over 13 months in 2013-2014. A representative sample of 10,651 individuals in 3410 households within 120 cluster segments identified 9913 people who were eligible for recruitment. CONCLUSION: The study methodology was robust and adequate to provide the first population-based estimates of the prevalence and causes of visual impairment and blindness in Trinidad and Tobago. Information was also gathered on risk factors, costs and quality of life associated with vision loss, and on normal ocular parameters for the population aged 40 years and older.