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

Self-reported Myopia in Trinidad and Tobago: A Cross-sectional Study

OBJECTIVE

The objective of this study was to determine the prevalence of self-reported myopia in Trinidad and Tobago.

MATERIALS AND METHODS

This study was a cross-sectional design, and data were collected using a validated structured questionnaire from January to April 2024. Systematic random sampling was used to select participants aged 15 and above to participate. Descriptive statistics were used to summarise the variables and the Chi-square test was used to assess for associations (P < 0.05).

RESULTS

A total of 350 participated in the study giving a response rate of 91.15%. Majority of the participants were female (n = 197, 56.3%), mixed race (n = 126, 36%), resided in urban areas (n = 172, 49.4%) and aged 18-35 years (n = 168, 48.3%). The prevalence of myopia was 40.9% and the prevalence was significantly associated with age group, ethnicity, level of education and religion (P < 0.05). Myopia was associated with family history, lifestyle, use of spectacles, daily use of computers, near work, outdoor activities, sleeping and having a father or mother with myopia (All P < 0.05). In addition, ocular diseases such as cataracts and glaucoma were among the most frequent reported conditions.

CONCLUSION

The myopia prevalence observed in our study validates age-related trends, offers estimates across diverse age groups, and reveals a significant association between myopia rates and family history, with a self-reported myopia rate higher than clinical testing surveys but in line with global prevalence reports.

The societal economic impact of vision impairment in adults 40 years and above: findings from the National Eye Survey of Trinidad and Tobago

BACKGROUND

Understanding and mitigating the societal economic impact of vision impairment (VI) is important for achieving the Sustainable Development Goals.

AIM

To estimate the prevalent societal economic impact of presenting VI in Trinidad and Tobago using bottom-up cost and utilisation data from the 2014 National Eye Survey of Trinidad and Tobago.

METHODS

We took a societal perspective to combine comprehensive, individual-level cost and utilisation data, with population-based prevalence estimates for VI, and additional data from a contemporaneous national eyecare system survey. We included direct (medical and non-medical) and indirect (productivity loss) costs, and intangible losses in total cost estimates, presented in 2014 Trinidad & Tobago (TT) dollars and UK sterling equivalent. We considered but excluded transfer payments and dead weight losses. Sensitivity analyses explored impact on total cost of parameter uncertainty and assumptions.

RESULTS

Individual utilisation and cost data were available for 65.5% (n = 2792/4263) and 59.0% (n = 2516/4263) eligible participants aged ≥40 years, respectively. Participant mean age was 58.4(SD 11.8, range 40-103) years, 56.3% were female. We estimated total societal cost of VI in 2014 at UK£365,650,241 (TT$3,842,324,655), equivalent to £675 per capita (population ≥40 years). Loss of wellbeing accounted for 73.3%. Excluding this, the economic cost was UK£97,547,222 (TT$1,025,045,399), of which indirect costs accounted for 70.5%, followed by direct medical costs (17.9%), and direct non-medical costs (11.6%).

CONCLUSION

This study provides a comprehensive estimate of the economic impact of vision loss in a Caribbean country, and highlights the extent to which affected individuals and their families bear the societal economic cost of vision impairment.

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.

A retrospective study of causes of visual impairment and use of low vision devices in the low vision clinic in Trinidad and Tobago

PURPOSE

To determine the causes of visual impairment and the use of low vision devices in patients attending the low vision clinic in Trinidad and Tobago.

METHODS

A retrospective study of the 222 patients attending the low vision clinic at the University of the West Indies, St Augustine Campus was conducted. The presenting visual acuity, causes of low vision and blindness, and prescribed low vision devices were recorded and analysed to determine the major causes of visual impairment and improvement in visual acuity with low vision aids.

RESULTS

Out of the total 222 participants, 66.66% (n = 148) had low vision while the rest (33.33%, n = 74) were legally blind. Glaucoma was the major cause of low vision (31.08%) and blindness (28.38%) followed by diabetic retinopathy (20.94%, low vision and 20.27%, blindness). A total of 193 low vision devices were prescribed, 79.79% (n = 154) near devices and 20.20% (n = 39) distance devices. The low vision devices were effective in improving both near visual acuity (120 participants reading 1M or 2M) and distance visual acuity (VA better than 3/60).

CONCLUSION

The major causes of vision impairment in Trinidad and Tobago were glaucoma and diabetic retinopathy and low vision devices are effective in improving visual acuity. A comprehensive approach to dealing with the causes of low vision and low vision services are required to mitigate the burden of visual impairment in the country.

Successful Aging Among Community-Dwelling Older Adults in Urban Areas of Liaoning Province: The Crucial Effect of Visual Ability

Purpose

Successful aging is an effective approach to coping with population aging; however, the definition and associated factors vary due to culture and demographic distribution differences. This study was designed to assess successful aging of the older adults in China and explore the associated factors.

Methods

A community-based cross-sectional study was performed in Liaoning, China. After double-cognitive function screening, 3558 older adults (1656 males and 1902 females) ≥65 years of age served as our subjects. Successful aging was assessed based on the following: physical disability; cognitive function; activities of daily living; and self-rated psychological/mood status.

Results

The rate of successful aging was 31.7% in males and 29.4% in females. After adjustment for age, multivariate logistic regression showed that successful aging was significantly associated with, in odds ratio sequence, visual ability, self-rated chronic disease, marital status, and filial piety in males, and with visual ability, self-rated chronic disease, watching television, and ethnicity in females.

Conclusion

The level of successful aging in China is lower than in other countries. Demographic characteristics, health status, individual behavior, and social-psychological factors are all associated with successful aging. Overall, visual ability had the most crucial role in successful aging for the older adults, whether males or females.

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.