Visual function after correction of distance refractive error with ready-made and custom spectacles: a randomized clinical trial

Modelling ready-made spectacle coverage for children and adults using a large global database

BACKGROUND/AIMS

To model the suitability of conventional ready-made spectacles (RMS) and interchangeable-lens ready-made spectacles (IRMS) with reference to prescribing guidelines among children and adults using a large, global database and to introduce a web-based application for exploring the database with user-defined eligibility criteria.

METHODS

Using refractive power and interpupillary distance data for near and distance spectacles prescribed to children and adults during OneSight clinics in 27 countries, from 2 January 2016 to 19 November 2019, we modelled the expected suitability of RMS and IRMS spectacle designs, compared with custom-made spectacles, according to published prescribing guidelines.

RESULTS

Records of 18 782 presbyopic adult prescriptions, 70 619 distance adult prescriptions and 40 862 paediatric prescriptions were included. Globally, 58.7%-63.9% of adults could be corrected at distance with RMS, depending on the prescribing cut-off. For presbyopic adult prescriptions, coverage was 44.1%-60.9%. Among children, 51.8% were eligible for conventional RMS. Coverage for all groups was similar to the above for IRMS. The most common reason for ineligibility for RMS in all service groups was astigmatism, responsible for 27.2% of all ineligible adult distance prescriptions using the strictest cut-off, 31.4% of children's prescriptions and 28.0% of all adults near prescriptions globally.

CONCLUSION

Despite their advantages in cost and convenience, coverage delivered by RMS is limited under current prescribing guidelines, particularly for children and presbyopic adults. Interchangeable designs do little to remediate this, despite extending coverage for anisometropia. Our free application allows users to estimate RMS coverage in specific target populations.

V. SD, Nagaraj S, Wittberg DM, Stamper RL, Keenan JD. Accuracy of autorefraction in an adult Indian population

Purpose

Autorefractors allow non-specialists to quickly assess refractive error, and thus could be a useful component of large-scale vision screening programs. In order to better characterize the role of autorefraction for public health outreach programs in resource-limited settings, the diagnostic accuracy of two autorefractors was assessed relative to subjective refraction in an adult Indian population.

Methods

An optometrist refracted a series of patients aged ≥50 years at an eye clinic in Bangalore, India using the Nidek ARK-900 autorefractor first, followed by the 3nethra Royal autorefractor, and then subjective refraction. The diagnostic accuracy of each autorefractor for myopia, hyperopia, and astigmatism was assessed using subjective refraction as the reference standard, and measures of agreement between refractions were calculated.

Results

A total of 197 eyes in 104 individuals (mean age 63 ± 8 years, 52% female) were evaluated. Both autorefractors produced spherical equivalent estimates that were on average more hyperopic than subjective refraction, with a measurement bias of +0.16 D (95%CI +0.09 to +0.23D) for Nidek and +0.42 D (95%CI +0.28 to +0.54D) for 3nethra. When comparing pairs of measurements from autorefraction and subjective refraction, the limits of agreement were approximately ±1D for the Nidek autorefractor and ±1.75D for the 3Nethra autorefractor. The sensitivity and specificity of detecting ≥1 diopter of myopia were 94.6% (95%CI 86.8–100%) and 92.5% (95%CI 88.9–97.5%) for the Nidek, and 89.2% (95%CI 66.7–97.4) and 77.5% (95%CI 71.2–99.4%) for the 3Nethra. The accuracy of each autorefractor increased at greater levels of refractive error.

Conclusions

The sensitivity and specificity of the Nidek autorefractor for diagnosing refractive error among adults ≥50 years in an urban Indian clinic was sufficient for screening for visually significant refractive errors, although the relatively wide limits of agreement suggest that subjective refinement of the eyeglasses prescription would still be necessary.

Is an integrated model of school eye health delivery more cost-effective than a vertical model? An implementation research in Zanzibar

Objective

To review and compare the cost-effectiveness of the integrated model (IM) and vertical model (VM) of school eye health programme in Zanzibar.

Methods and analysis

This 6-month implementation research was conducted in four districts in Zanzibar. Nine and ten schools were recruited into the IM and VM, respectively. In the VM, teachers conducted eye health screening and education only while these eye health components were added to the existing school feeding programme (IM). The number of children aged 6–13 years old screened and identified was collected monthly. A review of project account records was conducted with 19 key informants. The actual costs were calculated for each cost categories, and costs per child screened and cost per child identified were compared between the two models.

Results

Screening coverage was 96% and 90% in the IM and VM with 297 children (69.5%) from the IM and 130 children (30.5%) from VM failed eye health screening. The 6-month eye health screening cost for VM and IM was US$6 728 and US$7 355. The cost per child screened for IM and VM was US$1.23 and US$1.31, and the cost per child identified was US$24.76 and US$51.75, respectively.

Conclusion

Both models achieved high coverage of eye health screening with the IM being a more cost-effective school eye health delivery screening compared with VM with great opportunities for cost savings.

Association of Visual Acuity Improvement With Uncorrected Refractive Error in Patients New to Low Vision Clinics

Importance

There is substantial socioeconomic and individual burden from uncorrected refractive error (URE) and chronic ocular disease. Understanding the association of visual acuity (VA) reduction with URE and the adults most likely to benefit from refraction may help support clinical decision-making in ophthalmologic care and maximize patient outcomes.

Objectives

To assess the magnitude of VA improvement associated with URE among adults under ophthalmic care who obtain low vision rehabilitation (LVR) services and identify the characteristics of the patients who are most likely to experience improvement.

Design, Setting, and Participants

This retrospective case series assessed patients 20 years or older who were new to the LVR clinics from August 1, 2013, to December 31, 2015, and who had habitual VA between 20/40 and counting fingers (not including) and underwent refraction. Data analysis was performed from April 4, 2018, to December 20, 2019.

Exposures

Patient demographics and clinical data, including habitual and refraction VA, refraction, and disease diagnosis. Habitual VA was categorized as mild (VA worse than 20/40 and at least 20/60), moderate (VA worse than 20/60 and better than 20/200), severe (VA 20/200 or worse and better than 20/500), and profound (VA 20/500 or worse) vision impairment (VI).

Main Outcomes and Measures

At least 2-line VA improvement and any VA improvement (≥1-line) by refraction.

Results

Among the 2923 patients new to LVR clinics, 1773 (mean [SD] age, 70 [18.2] years; 1069 [60.3%] female) were included in these analyses. The mean habitual VA was 20/100 (mean [SD], 0.67 [0.36] logMAR). At least 2-line improvement was observed in 493 patients (27.8%), and any VA improvement was seen in 1023 patients (57.7%). At least 2-line improvement was observed in 54 patients (34.8%) with corneal disorders and was more likely seen among patients aged 40 to <65 years compared with those aged 20 to <40 years (odds ratio [OR], 1.57; 95% CI, 1.02-2.41), African American patients compared with white patients (OR, 1.41; 95% CI, 1.08-1.85), or patients with moderate VI compared with mild VI (OR, 1.36; 95% CI, 1.07-1.72).

Conclusions and Relevance

The findings suggest that URE is prevalent among patients with ocular disease and accessing LVR and that refractive evaluation should be considered for patients with ocular disease and reduced VA, especially working-age adults aged 40 to <65 years, African American patients, and those with moderate VI.

Evaluation of vision screening of 5-15-year-old children in three Tongan schools: comparison of The Auckland Optotypes and Lea symbols

Background

Comprehensive vision screening programmes for children are an important part of public health strategy, but do not exist in many countries, including Tonga. This project set out to assess: (1) the functional vision of children attending primary schools in Tonga and (2) how a new recognition acuity test (The Auckland Optotypes displayed on a tablet computer) compares to use of a standardised eye chart in this setting.

Methods

Children from three Tongan primary schools were invited to participate. Acuity testing was conducted using a standardised recognition acuity chart (Lea symbols) and the tablet test displaying two formats of The Auckland Optotypes. Measures of ocular alignment, stereo acuity and non‐cycloplegic photorefraction were also taken.

Results

Parents of 249 children consented to participate. One child was untestable. Only 2.8 per cent of testable children achieved visual acuity worse than 0.3 logMAR in the weaker eye. Results from the Spot Photoscreener suggested that no children had myopia or hyperopia, but that some children had astigmatism. The tablet test was practical in a community setting, and showed ±0.2 logMAR limits of agreement with the Lea symbols chart.

Conclusion

The sample of children in Tongan primary schools had good functional vision. A modified version of the tablet acuity test is a promising option for vision screening in this context.

A Randomized Noninferiority Trial of Wearing Adjustable Glasses versus Standard and Ready-made Spectacles among Chinese Schoolchildren: Wearability and Evaluation of Adjustable Refraction III

PURPOSE

To compare wear of standard, adjustable, and ready-made glasses among children.

DESIGN

Randomized, controlled, open-label, noninferiority trial.

PARTICIPANTS

Students aged 11 to 16 years with presenting visual acuity (VA) ≤6/12 in both eyes, correctable to ≥6/7.5, subjective spherical equivalent refractive error (SER) ≤-1.0 diopters (D), astigmatism and anisometropia both <2.00 D, and no other ocular abnormalities.

METHODS

Participants were randomly allocated (1:1:1) to standard glasses, ready-made glasses, or adjustable glasses based on self-refraction. We recorded glasses wear on twice-weekly covert evaluation by head teachers (primary outcome), self-reported and investigator-observed wear, best-corrected visual acuity (BCVA) (not prespecified), children's satisfaction, and value attributed to glasses.

MAIN OUTCOME MEASURE

Proportion of glasses wear on twice-weekly covert evaluation by head teachers over 2 months.

RESULTS

Among 379 eligible participants, 127 were allocated to standard glasses (mean age, 13.7 years; standard deviation [SD], 1.0 years; 54.3% were male), 125 to ready-made (mean age, 13.6; SD, 0.83; 45.6%), and 127 to adjustable (mean age, 13.4 years; SD, 0.85; 54.3%). Mean wear proportion of adjustable glasses was significantly lower than for standard glasses (45% vs. 58%; P = 0.01), although the adjusted difference (90% confidence interval [CI], -19.0% to -3.0%) did not meet the prespecified inferiority threshold of 20%. Self-reported (90.2% vs. 84.8%, P = 0.64) and investigator-observed (44.1% vs. 33.9%, P = 0.89) wear did not differ between standard and adjustable glasses, nor did satisfaction with (P = 0.97) or value attributed to study glasses (P = 0.55) or increase in quality of life (5.53 [SD, 4.47] vs. 5.68 [SD, 4.34] on a 100-point scale, P > 0.30). Best-corrected visual acuity with adjustable glasses was better (P < 0.001) than with standard glasses. Change in power of study lenses at the end of the study (adjustable: 0.65 D, 95% CI, 0.52-0.79; standard, 0.01 D; 95% CI, -0.006 to 0.03, P < 0.001) was greater for adjustable glasses, although interobserver variation in power measurements may explain this. Lens scratches and frame damage were more common with adjustable glasses, whereas lens breakage was less common than for standard glasses.

CONCLUSIONS

Proportion of wear was lower with adjustable glasses, although VA was better and measures of satisfaction and quality of life were not inferior to standard glasses.

The use of patient-reported outcome research in modern ophthalmology: impact on clinical trials and routine clinical practice

This review article considers the rising demand for patient-reported outcome measures (PROMs) in modern ophthalmic research and clinical practice. We review what PROMs are, how they are developed and chosen for use, and how their quality can be critically appraised. We outline the progress made to develop PROMs in each clinical subspecialty. We highlight recent examples of the use of PROMs as secondary outcome measures in randomized controlled clinical trials and consider the impact they have had. With increasing interest in using PROMs as primary outcome measures, particularly where interventions have been found to be of equivalent efficacy by traditional outcome metrics, we highlight the importance of instrument precision in permitting smaller sample sizes to be recruited. Our review finds that while there has been considerable progress in PROM development, particularly in cataract, glaucoma, medical retina, and low vision, there is a paucity of useful tools for less common ophthalmic conditions. Development and validation of item banks, administered using computer adaptive testing, has been proposed as a solution to overcome many of the traditional limitations of PROMs, but further work will be needed to examine their acceptability to patients, clinicians, and investigators.

Evaluating Self-Refraction and Ready-Made Spectacles for Treatment of Uncorrected Refractive Error

PURPOSE

Uncorrected refractive error is the leading cause of visual impairment worldwide and has significant quality of life and economic implications. Treatment with subjective refraction and custom-made spectacles requires expensive equipment and highly trained personnel. We examine several alternatives.

METHODS

Patients were taught to self-refract using two devices: AdSpecs and the I-test Vision Screener. Ready-made spectacles were fit to the self-refraction and visual acuity (VA) was measured. Donated-spectacles were fit to subjective refraction and VA was measured. Self-refraction and donated spectacles spherical equivalent (SE) and VA were compared to subjective refraction SE and VA.

RESULTS

About 57 patients (102 eyes) were enrolled in the study. Patients accurately determined refractive power with self-refraction by both AdSpecs and the I-test (compared to subjective refraction SE, r² = 0.97 and r² = 0.94, respectively). SE of donated spectacles fit well with self-refraction SE (r² = 0.91). There was no significant difference between best-corrected VA by subjective refraction and VA treated by ready-made spectacles fit to self-refraction by either device (analysis of variance (ANOVA), p non-significant). Patients fit with donated spectacles had significantly worse VA than best-corrected VA by subjective refraction (ANOVA, p < 0.01), although 80% improved to >20/40.

CONCLUSION

Patients accurately self-refract using both devices and ready-made spectacles fit to self-refraction have excellent visual outcomes. Donated spectacles have worse visual outcomes but might be useful in a subset of patients. Ready-made spectacles fit to self-refraction may provide a treatment alternative to uncorrected refractive error.

Ready-made and custom-made eyeglasses in India: a cost-effectiveness analysis of a randomised controlled trial

Objective

Ready-made spectacles have been suggested as a less resource-intensive treatment for the millions of people living with uncorrected refractive error (URE) in low-income environments. In spite of this interest, there have been no published economic evaluations examining the cost-effectiveness of ready-made spectacles. This study aims to determine the relative cost-effectiveness of offering ready-made spectacles (RMS) relative to no intervention as well as the relative cost-effectiveness of custom-made spectacles (CS) relative to RMS to treat URE.

Methods and analysis

The relative cost-effectiveness of RMS relative to CS and no intervention was tested through a cost-effectiveness analysis from the health service provider perspective conducted alongside a double-masked randomised controlled trial in an urban hospital in Delhi, India. Participants were adults aged 18–45 years with ≥1 dioptre (D) of URE.

Results

There was no significant difference between the effectiveness of the CS and RMS interventions in improving visual acuity, but the CS was over four times the price of the RMS per patient (204 INR (US$2.42) and 792 INR (US$11.22)). The cost per unit improvement in logarithm of the minimum angle of resolution (logMAR) relative to baseline with the RMS intervention was 407 INR (US$4.35). Existing estimates of utility resulting from improvements in visual acuity result in incremental cost per quality-adjusted life years gained of between 212 INR and 1137 INR (US$0.44–US$23.74) depending on the source of the utility estimate and assumed expected life of the spectacles.

Conclusion

RMS represent a significantly cost-effective option for spectacle provision in low-resource settings. The RMS programme was substantially cheaper than an equivalent CS intervention while being effective in improving visual acuity for the majority of adults with refractive error in this setting. These findings provide further support for including RMS in programmes to address URE.

Trial registration number

NCT00657670, Results.

Patient-reported Outcomes for Assessment of Quality of Life in Refractive Error: A Systematic Review

SIGNIFICANCE

This review has identified the best existing patient-reported outcome (PRO) instruments in refractive error. The article highlights the limitations of the existing instruments and discusses the way forward.

PURPOSE

A systematic review was conducted to identify the types of PROs used in refractive error, to determine the quality of the existing PRO instruments in terms of their psychometric properties, and to determine the limitations in the content of the existing PRO instruments.

METHODS

Articles describing a PRO instrument measuring 1 or more domains of quality of life in people with refractive error were identified by electronic searches on the MEDLINE, PubMed, Scopus, Web of Science, and Cochrane databases. The information on content development, psychometric properties, validity, reliability, and responsiveness of those PRO instruments was extracted from the selected articles. The analysis was done based on a comprehensive set of assessment criteria.

RESULTS

One hundred forty-eight articles describing 47 PRO instruments in refractive error were included in the review. Most of the articles (99 [66.9%]) used refractive error-specific PRO instruments. The PRO instruments comprised 19 refractive, 12 vision but nonrefractive, and 16 generic PRO instruments. Only 17 PRO instruments were validated in refractive error populations; six of them were developed using Rasch analysis. None of the PRO instruments has items across all domains of quality of life. The Quality of Life Impact of Refractive Correction, the Quality of Vision, and the Contact Lens Impact on Quality of Life have comparatively better quality with some limitations, compared with the other PRO instruments.

CONCLUSIONS

This review describes the PRO instruments and informs the choice of an appropriate measure in refractive error. We identified need of a comprehensive and scientifically robust refractive error-specific PRO instrument. Item banking and computer-adaptive testing system can be the way to provide such an instrument.

Self-refraction, ready-made glasses and quality of life among rural myopic Chinese children: a non-inferiority randomized trial

PURPOSE

To study, for the first time, the effect of wearing ready-made glasses and glasses with power determined by self-refraction on children's quality of life.

METHODS

This is a randomized, double-masked non-inferiority trial. Children in grades 7 and 8 (age 12-15 years) in nine Chinese secondary schools, with presenting visual acuity (VA) ≤6/12 improved with refraction to ≥6/7.5 bilaterally, refractive error ≤-1.0 D and <2.0 D of anisometropia and astigmatism bilaterally, were randomized to receive ready-made spectacles (RM) or identical-appearing spectacles with power determined by: subjective cycloplegic retinoscopy by a university optometrist (U), a rural refractionist (R) or non-cycloplegic self-refraction (SR). Main study outcome was global score on the National Eye Institute Refractive Error Quality of Life-42 (NEI-RQL-42) after 2 months of wearing study glasses, comparing other groups with the U group, adjusting for baseline score.

RESULTS

Only one child (0.18%) was excluded for anisometropia or astigmatism. A total of 426 eligible subjects (mean age 14.2 years, 84.5% without glasses at baseline) were allocated to U [103 (24.2%)], RM [113 (26.5%)], R [108 (25.4%)] and SR [102 (23.9%)] groups, respectively. Baseline and endline score data were available for 398 (93.4%) of subjects. In multiple regression models adjusting for baseline score, older age (p = 0.003) and baseline spectacle wear (p = 0.016), but not study group assignment, were significantly associated with lower final score.

CONCLUSION

Quality of life wearing ready-mades or glasses based on self-refraction did not differ from that with cycloplegic refraction by an experienced optometrist in this non-inferiority trial.

Refractive error in underserved adults: causes and potential solutions

PURPOSE OF REVIEW

To evaluate the epidemiology of uncorrected refractive errors (URE) in adults both in the United States and globally, health outcomes impacted by URE, common barriers to treatment, and propose potential interventions.

RECENT FNDINGS

URE is the main cause of visual impairment and the second leading cause of blindness globally. Rates of URE are rising, and cause disability that reduces productivity, economic earnings, and the quality of life of affected individuals. Economic barriers, healthcare access, and sociocultural constraints are among the most fundamental barriers to correcting URE. However, innovative approaches are poised to lower rates of URE.

SUMMARY

URE is a leading cause of preventable visual impairment with serious health consequences. Numerous social and financial barriers are associated with the high prevalence of URE in low-income adults. Novel delivery programs for eyeglasses and programs to provide refractive surgery to correct refractive error could decrease rates of URE.

Do recycled spectacles meet the refractive needs of a developing country?

PURPOSE

The aim was to compare the power of spectacles donated to a recycled spectacle program to the custom-made spectacle refractive prescriptions dispensed in a developing country.

METHODS

Two hundred consecutive prescriptions were audited in an optical dispensary in Timor-Leste, a developing nation. These refractions were compared against measurements of 2,075 wearable donated spectacles. We determined how many of the 200 prescriptions could be matched to a donated spectacle measurement, how many donated spectacles could be tried for each prescription and how long it would take to find the matched spectacles.

RESULTS

There were 1,854 donated spectacles identified as being suitable for comparison with the 200 refractive prescriptions. Twenty-nine out of 200 prescriptions (14.5 per cent) were matched to at least one pair of donated spectacles.

CONCLUSION

Recycling all spectacles is not cost-effective in a developing country that has the ability to make custom-made spectacles and dispense ready-made spectacles.

Functional and visual acuity outcomes of cataract surgery in Timor-Leste (East Timor)

PURPOSE

To report functional outcomes following cataract surgery in Timor-Leste.

METHODS

Pre- and post-intervention study measuring visual function improvement following cataract surgery. Presenting visual acuity (VA) was measured and visual function documented using the Indian vision function questionnaire (IND-VFQ).

RESULTS

All 174 persons undergoing cataract surgery from November 2009 to January 2011 in Timor-Leste were included. Mean age was 65.4 years; 113 (64.9%) were male, 143 (82.1%) were from a rural background and 151 (86.8%) were illiterate. Pre-operatively, 77 of 174 patients (44.3%, 95% confidence interval, CI, 37.0-51.7%) were blind (VA ≤3/60), 77 (44.3%, 95% CI 37.0-51.7%) were visually impaired (VA <6/18->3/60), while 20 (11.5%, 95% CI 7.4-16.9%) had presenting acuity ≥6/18 in the better eye. Following surgery, significant improvement in visual function was demonstrated by an effect size of 2.8, 3.7 and 3.9 in the domains of general functioning, psychosocial impact and visual symptoms, respectively. Four weeks following surgery, 85 patients (48.9%, 95% CI 41.5-66.3%) had a presenting VA ≥6/18, 74 (42.5%, 95% CI 35.3-45.9%) were visually impaired and 15 (8.6%, 95% CI 5.0-13.6%) were blind. IND-VFQ improvement occurred even in patients remaining visually impaired or blind following surgery.

CONCLUSION

In this setting, cataract surgery led to a significant improvement in visual function but the VA results did not meet World Health Organization quality criteria. IND-VFQ results, although complementary to clinical VA outcomes did not, in isolation, reflect the need to improve program quality.

Self-adjustable glasses in the developing world

Uncorrected refractive errors are the single largest cause of visual impairment globally. Refractive errors are an avoidable cause of visual impairment that are easily correctable. Provision of spectacles is a cost-effective measure. Unfortunately, this simple solution becomes a public health challenge in low- and middle-income countries because of the paucity of human resources for refraction and optical services, lack of access to refraction services in rural areas, and the cost of spectacles. Low-cost approaches to provide affordable glasses in developing countries are critical. A number of approaches has been tried to surmount the challenge, including ready-made spectacles, the use of focometers and self-adjustable glasses, among other modalities. Recently, self-adjustable spectacles have been validated in studies in both children and adults in developed and developing countries. A high degree of agreement between self-adjustable spectacles and cycloplegic subjective refraction has been reported. Self-refraction has also been found to be less prone to accommodative inaccuracy compared with non-cycloplegic autorefraction. The benefits of self-adjusted spectacles include: the potential for correction of both distance and near vision, applicability for all ages, the empowerment of lay workers, the increased participation of clients, augmented awareness of the mechanism of refraction, reduced costs of optical and refraction units in low-resource settings, and a relative reduction in costs for refraction services. Concerns requiring attention include a need for the improved cosmetic appearance of the currently available self-adjustable spectacles, an increased range of correction (currently −6 to +6 diopters), compliance with international standards, quality and affordability, and the likely impact on health systems. Self-adjustable spectacles show poor agreement with conventional refraction methods for high myopia and are unable to correct astigmatism. A limitation of the fluid-filled adjustable spectacles (AdSpecs, Adaptive Eyecare Ltd, Oxford, UK) is that once the spectacles are self-adjusted and the power fixed, they become unalterable, just like conventional spectacles. Therefore, they will need to be changed as refractive power changes over time. Current costs of adjustable spectacles are high in developing countries and therefore not affordable to a large segment of the population. Self-adjustable spectacles have potential for “upscaling” if some of the concerns raised are addressed satisfactorily.

Clinical outcomes following the dispensing of ready-made and recycled spectacles: a systematic literature review

Uncorrected refractive error is the leading cause of global visual impairment. Given resource constraints in developing countries, the gold standard method of refractive error correction, custom-made spectacles, is unlikely to be available for some time. Therefore, ready-made and recycled spectacles are in wide use in the developing world. To ensure that refractive error interventions are successful, it is important that only appropriate modes of refractive error correction are used. As a basis for policy development, a systematic literature review was conducted of interventional studies analysing visual function, patient satisfaction and continued use outcomes of ready-made and recycled spectacles dispensed to individuals in developing countries with refractive errors or presbyopia. PubMed and CINAHL were searched by MESH terms and keywords related to ready-made and recycled spectacle interventions, yielding 185 non-duplicated papers. After applying exclusion criteria, eight papers describing seven studies of clinical outcomes of dispensing ready-made spectacles were retained for analysis. The two randomised controlled trials and five non-experimental studies suggest that ready-made spectacles can provide sufficient visual function for a large portion of the world's population with refractive error, including those with astigmatism and/or anisometropia. The follow-up period for many of the studies was too short to confidently comment on patient satisfaction and continued-use outcomes. No studies were found that met inclusion criteria and discussed recycled spectacles. The literature also notes concerns about quality and cost effectiveness of recycled spectacles, as well as their tendency to increase developing countries' reliance on outside sources of help. In light of the findings, the dispensing of ready-made spectacles should be favoured over the dispensing of recycled spectacles in developing countries.

A method for the prescription of inexpensive spectacles by non-specialist healthcare workers: S-Glasses

PURPOSE

Globally, 153 million people are visually impaired from uncorrected refractive error. The aim of this research was to verify a method whereby autorefractors could be used by non-specialist health-workers to prescribe spectacles, which used a small stock of preformed lenses that fit frames with standardised apertures. These spectacles were named S-Glasses (Smart Glasses).

PATIENTS AND METHODS

This prospective, single-cohort exploratory study enrolled 53 patients with 94 eligible eyes having uncorrected vision of 6/18 or worse. Eyes with best-corrected vision worse than 6/12 were excluded. An autorefractor was used to obtain refractions, which were adjusted so that eyes with astigmatism less than 2.00 dioptres (D) received spherical equivalent lenses, and eyes with more astigmatism received toric lenses with a 2.50 D cylindrical element set at one of four meridians. The primary outcome was to compare S-Glasses vision with the WHO definition of visual impairment (6/18). Where astigmatism was 2.00 D or greater, comparison with spherical equivalent was made. Mixed-model analysis with repeated effect was used to account for possible correlation between the vision of fellow eyes of the same individual.

RESULTS

S-Glasses corrected 100% of eyes with astigmatism less than 3.00 D and 69% of eyes with astigmatism of 3.00 D or greater. Spherical equivalent lenses corrected 25% of eyes with astigmatism of 2.00-2.99 D and 11% with astigmatism of at least 3.00 D.

DISCUSSION

S-Glasses could be beneficial to resource-poor populations without trained refractionists. This novel approach, using approximate toric lenses, results in superior vision for astigmatic patients compared with the practice of providing spherical equivalent alone.