Renee du Toit

Prevalence and causes of blindness and low vision in Timor-Leste

Aim: To estimate the prevalence and causes of blindness and low vision in people aged ⩾40 years in Timor-Leste. Method: A population-based cross-sectional survey using multistage cluster random sampling to identify 50 clusters of 30 people. A cause of vision loss was determined for each eye presenting with visual acuity worse than 6/18. Results: Of 1470 people enumerated, 1414 (96.2%) were examined. The age, gender and domicile-adjusted prevalence of functional blindness (presenting vision worse than 6/60 in the better eye) was 7.4% (95% CI 6.1 to 8.8), and for blindness at 3/60 was 4.1% (95% CI 3.1 to 5.1). The adjusted prevalence for low vision (better eye presenting vision of 6/60 or better, but worse than 6/18) was 17.7% (95% CI 15.7 to 19.7). Gender was not a risk factor for blindness or low vision, but increasing age, illiteracy, subsistence farming, unemployment and rural domicile were risk factors for both. Cataract was the commonest cause of blindness (72.9%) and an important cause of low vision (17.8%). Uncorrected refractive error caused 81.3% of low vision. Conclusion: Strategies that make good-quality cataract and refractive error services available, affordable and accessible, especially in rural areas, will have the greatest impact on vision impairment.

Eye care in Timor-Leste: a population-based study of utilization and barriers

Background:  To determine utilization of Western‐style conventional health services for eye problems in Timor‐Leste, and barriers to seeking that care.

The Impact of Reduced Distance and Near Vision on the Quality of Life of Adults in Timor-Leste

PURPOSE To determine the independent, relative, and combined impact of reduced distance and near vision on the vision-specific quality of life (VS QOL) of adults in Timor-Leste. DESIGN A population-based cross-sectional eye health survey was conducted in urban and rural areas in Timor-Leste. PARTICIPANTS Participants were 40 years or older. Those with better eye presenting distance vision worse than 6/18, and every third participant with 6/18 or better vision, completed the VS QOL questionnaire: in total 704 of the 1414 participants. METHODS Distance and near visual acuities were measured and eye health was assessed. The VS QOL questionnaire administered by interview was analyzed using Rasch analysis, univariate analysis, and linear regression to determine associations between VS QOL, demographic factors, and levels of visual impairment. MAIN OUTCOME MEASURES The Timor-Leste VS QOL questionnaire results. RESULTS Rasch analysis confirmed that for participants both with and without visual impairment, the Timor-Leste VS QOL questionnaire provided a valid and reliable measure, was unidimensional, and had appropriate response categories. There was a consistent pattern of deterioration in VS QOL as vision worsened: for each category of distance- and near-vision impairment, there was an independent and significant change in Timor-Leste VS QOL scores between no visual impairment and either mild, moderate, or severe impairment (P < 0.05). Combined distance- and near-vision impairment was associated with a greater impact on VS QOL than categories separately, the impact of severe distance- and near-vision impairment being the greatest and clinically significant: -3.05 (95% confidence interval [CI], -3.60 to -2.49; P<0.05; and 95% CI, <-1.0). Distance vision (37.2%) contributed relatively more than near vision (4.7%) to the total variance in VS QOL (41.9%). Older people, those not married, not literate, and rural dwellers had significantly worse Timor-Leste VS QOL scores (P < 0.05). CONCLUSIONS This study provides evidence of independent dose-response relationships between distance- and near-vision impairment and poorer VS QOL. Distance-vision impairment had a relatively larger impact on VS QOL than near-vision impairment. Combined distance- and near-vision impairment was associated with a greater impact on VS QOL compared with the independent impact of distance- or near-vision impairment at similar levels.

Tolerance to prism induced by readymade spectacles: setting and using a standard.

Purpose. To determine first how much induced horizontal and vertical prism could be comfortably tolerated with readymade spectacle wear. Ultimately, the purpose is to develop a guide for dispensing decisions for blindness prevention programs in low-resource countries. Methods. Nine participants each wore plano spectacles with differing prism power for 8 h (plano control). If visual discomfort could not be tolerated, participants removed the spectacles, noting duration of wear and reason for discontinuation. Distance and near visual comfort were rated, and participants asked if they would be able to adapt to wearing the spectacles. Results. On average, half of the wearing time was spent on concentrated near viewing tasks. The highest prism powers (1&Dgr; BU, 2&Dgr; BO, 2&Dgr; BI) could not be worn for 8 h by the majority of participants. Comfort ratings at near (similar to those at distance) were statistically significantly different when the highest prism power was compared with each of the lower powers (vertical prism: both the control and 0.5 &Dgr; differed from 1 &Dgr;; horizontal prism: the control, 0.5 &Dgr; and 1 &Dgr; all differed from 2 &Dgr;). Conclusions. Most spectacle wearers would likely comfortably tolerate ≤0.5 &Dgr; vertical, ≤1.0 &Dgr; base out, or ≤1.0 &Dgr; base in induced prism. A guide to the maximum interpupillary distance/optical center distance disparities likely to be comfortably tolerated with varying spectacle powers was formulated. Powers up to ±1.50 DS are unlikely to have sufficient lens decentration to cause discomfort. This small study supports the feasibility of using readymade spectacles in low-resource settings even though optical center distance may be different to the interpupillary distance of the wearer. It would seem that fear of visual discomfort because of induced prism need not preclude the use of readymade spectacles, potentially correcting about 75% of refractive error and presbyopia, mostly with powers +3.00 to −3.00 DS. Further study is needed to more fully address these issues.

Eye disease and care at hospital clinics in Cook Islands, Fiji, Samoa and Tonga.

Purpose:  To obtain eye disease and care data to assist with service planning in Cook Islands, Fiji, Samoa and Tonga.

Affordable ready-made spectacles for use in blindness prevention programmes: setting standards of quality.

© 2006 Royal Australian and New Zealand College of Ophthalmologists course carefully followed for metastatic disease, and the patient described in our report continues to be followed at regular intervals and has not demonstrated clinical, radiographic or laboratory signs of metastatic disease. Finally, we are in agreement that other treatment modalities (such as plaque brachytherapy) would have been effective in this patient. However, as we pointed out in our Introduction, the treatment of choroidal melanoma involves a delicate balance between preventing metastasis and preserving vision, and in this case, after an extensive informed consent process, the patient decided to try an experimental treatment in an effort to preserve visual acuity. Fortunately in this case an excellent outcome was achieved, with completion regression of the lesion and preservation of 6/6 visual acuity.

Applying standards to readymade spectacles used in low-resource countries.

Purpose. To test the applicability of standards of appearance, construction, optical quality and performance, and durability proposed for readymade spectacles to be used by eye care programs in low-resource countries. Methods. Orders of readymade spectacles were procured from three suppliers by an eye care program in Timor-Leste. Feedback regarding quality was given to one supplier before placing subsequent orders. Spectacles were randomly selected from each order: 250 for powers +3.00 to −3.00 diopter sphere (DS), being of most interest to eye care programs, and 100 from ±3.50 DS and ±4.00 DS powers combined. An additional 100 spectacles of infrequently dispensed higher powers were sourced and tested. Every appliance was assessed by a single investigator against items of the proposed standards. A pass or fail was determined for each appliance for each standard. Based on this experience, the utility of application of the proposed standards was appraised. Results. With the exception of impact resistance, it was possible to test spectacles against all proposed standards. Cost was no predictor of quality. Of a sample of high power spectacles, 65% failed at least one standard. For low power samples, as few as 2.8% failed. Quality improved with feedback to the supplier. Conclusions. Standards testing can be accommodated with a combination of manufacturer/supplier batch testing and program evaluation of spectacle units. With limited skill and equipment (lensmeter, pupillary distance rule, and caliper), and an ongoing interaction with its supplier, an eye care program can apply the proposed standards and influence the quality of spectacles supplied.

Spectacles in Fiji: need, acquisition, use and willingness to pay

Background:  Little information is available regarding the perceived need, previous acquisition, use and willingness to pay for spectacles in Fiji, on which to base spectacle provision services.

Management of refractive errors

Uncorrected refractive error accounts for half of the global burden of avoidable vision impairment and nearly a third of the global burden of avoidable blindness.1 2 Globally, 153 million people have visual impairment or are blind due to uncorrected refractive error and the majority live in low income countries.1 Additionally, 410 million people have difficulty with near tasks because they lack reading glasses.2 Interventions to treat refractive error, such as spectacles, are cost-effective and in high income settings are readily accessible, but refractive errors are often not diagnosed or referred and barriers to the use of services exist.1 Under-corrected refractive error can account for as much as 75% of all impairment of vision in high income countries 1 3 4 5 and it may markedly affect quality of life.5 Minor reduction in vision (<6/12 or just below the driving standard) has been associated with an increased risk of death and physical, social, and psychological problems in people older than 50 years (box 1).6 w1-7 The global economic impact of uncorrected refractive error is an estimated 268.8 billion international dollars, based on population and economic data combined with a meta-analysis of prevalence studies.7 We provide an overview of the public health significance of refractive error, its management, and referral strategies for primary care practitioners. #### Box 1 Consequences of minor vision impairment (<6/12) in people older than 50 years ##### Increased social isolation ##### Increased morbidity ##### Increased mortality #### Sources and selection criteria In October 2008 and May 2009 we searched the Cochrane Collaboration database for reviews and clinicaltrials.gov for current trials, returning 420 studies. We also searched Medline and PubMed for articles published between 1 January 2000 and 1 May 2009, using MESH terms and combinations including …

Stated and Actual Willingness to Pay for Spectacles in Timor-Leste

ABSTRACT Purpose: To conduct a survey of willingness to pay for ready-made spectacles in the low-resource country of Timor-Leste, and, uniquely, subsequent validation with actual payment information. Methods: A systematic random sampling strategy was used to apply a binary with follow-up stated willingness to pay methodology. Findings were validated by comparing the amount declared willing to pay with the actual price paid at a subsequent visit. Results: Of the 152 participants (96.2%; mean age 50.9 ± 13.2 years; 50.0% female) agreeable to wearing spectacles if required, 84.9% were willing to pay for them, with 82.9% of these willing to pay at least United States dollars (USD) 0.10. By multivariate analysis, increasing age and owning fewer animals were significantly and independently associated with unwillingness to pay at least USD 0.10. Of the survey participants agreeable to wearing spectacles who attended a later visit (113/152; 74.3%; 53.1% female), the 80.5% who would benefit were offered spectacles, first for USD 1.00. If declined, this was revised to USD 0.10. If this was declined, the spectacles were dispensed, unknown to subsequent attendees, at no charge. The predictive value of stated willingness to pay at least USD 0.10 was 96.3%. Conclusions: Binary with follow-up stated willingness to pay with validation against actual payment was successfully applied to spectacles in Timor-Leste.