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

Abstract

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 populationbased 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.ARTICLE HISTORY

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

“…7 A recently conducted National Eye Study of Trinidad and Tobago (NESTT) reported blindness prevalence of 0.73% and moderate to severe visual impairment (MVI) of 5.34% in adults above 40 years of age. 8 , 9 The major causes of blindness were reported to be glaucoma (28.6%) and cataract (25.7%), followed by diabetic retinopathy (11.4%). The major causes of moderate to severe visual impairment were uncorrected refractive error (44.0%) and cataract (30.1%).…”

“…The major causes of moderate to severe visual impairment were uncorrected refractive error (44.0%) and cataract (30.1%). 8 , 9 …”

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

“…With aging, organ function deteriorates and the incidence of visual impairment among the older adults increases. 26 It has been reported that visual impairment has an impact on the physical and mental health of the older adults, 27 including depression and reduced life satisfaction, affecting participation in social activities and independent ADL. Interestingly, a previous study 8 on SA also explored the impact of visual ability, but the effect was not strong, possibly because of different evaluation criteria.…”

Impact of Vision Loss on Health-Related Quality of Life in Trinidad and Tobago

“…Finally, our sincere thanks to everyone in the National Eye Survey of Trinidad and Tobago Study Group. 2…”

“…Details are provided elsewhere. 2 Briefly, we sampled 9913 eligible people aged >5 years, including 4263 aged >40 years, residing in 3556 households (95.9% coverage) in 120 clusters, using multi-stage, random cluster sampling with probability-proportional-to-size methods. We measured presenting distance and near visual acuity outside households, using Logarithm of the Minimum Angle of Resolution (LogMAR) charts at 3m and 40cm, respectively, and standardized protocols (Stage 1).…”