Correction of refractive error and presbyopia in Timor-Leste

AIM: To investigate the aspects of spectacle correction of vision-impairing refractive error and presbyopia in those aged >or=40 years in Timor-Leste. METHOD: A population-based cross-sectional survey with cluster random sampling was used to select 50 clusters of 30 people. Those who had uncorrected or undercorrected refractive error (presenting acuity worse than 6/18, but at least 6/18 with pinhole), uncorrected or undercorrected presbyopia (near vision worse than N8), and/or who were using or had used spectacles were identified. Dispensing history, willingness to wear and willingness to pay for spectacles were elicited. RESULTS: Of 1470 people enumerated, 1414 were examined (96.2%). The "met refractive error need" in the sample was 2.2%, and the "unmet refractive error need" was 11.7%. The "refractive error correction coverage" was 15.7%. The "met presbyopic need" was 11.5%, and the "unmet presbyopic need" was 32.3%. The "presbyopia correction coverage" was 26.2%. Lower correction coverage was associated with rural domicile, illiteracy and farming. Of the sample, 96.0% were willing to wear spectacles correcting impaired vision. Of these, 17.0% were willing to pay US$3 ( pound 1.52, euro 2.24) for spectacles, whereas 50.2% were unwilling to pay US$1 ( pound 0.51, euro 0.75). Women and rural dwellers were less likely to be willing to pay at least US$1 for spectacles. CONCLUSION: Refractive error and presbyopia correction coverage rates are low in Timor-Leste. There is a large need for spectacles, especially for elderly and illiterate people, farmers and rural dwellers: those least able to pay for them. An equitable cross-subsidisation spectacle system should be possible.     

徐州市中小学生近视筛查与矫正情况分析

目的:了解江苏省徐州市6～18岁中小学生近视筛查与矫正情况。方法:横断面随机整群抽样研究,于2020-09/12以学校为单位抽取徐州市70所中小学校进行近视筛查。参与抽样63 488人,剔除不合格记录后,最终纳入6～18岁中小学生58 149人,并分析其不同年龄、性别、地区、近视程度下的近视及矫正情况。结果:徐州市6～18岁中小学生筛查性近视率为49.26%,近视患病率随年龄增长呈增加的趋势(P<0.01),近视程度随年龄增加逐渐加深,女生近视患病率高于男生(53.70%vs 45.67%,P<0.01),城市中小学生近视患病率高于乡镇(55.40%vs 45.10%,P<0.01)。框架眼镜矫正率为31.11%,足矫率为60.23%,同时矫正率随着年龄的增长逐渐增高(P<0.01),女生矫正率高于男生(32.45%vs 29.84%,P<0.01),但女生足矫率却低于男生(56.60%vs 63.98%,P<0.01)。城市中小学生矫正率和足矫率均高于乡镇(46.50%vs 18.33%,62.20%vs 56.07%,P<0.01)。结论:...     

Prevalence of refractive error,presbyopia, and unmet need of spectacle coverage in a northern district of Bangladesh: Rapid Assessment of Refractive Error study

Purpose: To determine the prevalence of refractive error (RE), presbyopia, spectacle coverage, and barriers to uptake optical services in Bangladesh.

Method: Rapid assessment of refractive error (RARE) study following the RARE protocol was conducted in a northern district (i.e., Sirajganj) of Bangladesh (January 2010–December 2012). People aged 15–49 years were selected, and eligible participants had habitual distance and near visual acuity (VA) measured and ocular examinations were performed in those with VA<6/18. Those with phakic eyes with VA <6/18, but improving to ≥6/18 with pinhole or optical correction, were considered as RE and people aged ≥35 years with binocular unaided near vision of <N8 were considered presbyopic.

Result : A total of 3,043 people were examined, of which 143 had RE (4.7%, 95% CI: 3.9–5.5). Among people aged ≥35 years (n = 1402), 869 had presbyopia (62.0, 95% CI: 59.4–64.5). Spectacle coverage for RE and presbyopia were 13.3% (95% CI 7.7–18.9) and 3.2% (95% CI 2.2–4.6), respectively. “Unaware of the problem” was the main reason for not utilizing any optical services among the people with RE (92.8%) and presbyopia (89.5%). Extrapolating the survey findings to the 2011 national census data, the magnitude of RE among people aged 15–49 years in Bangladesh is estimated to be 3,493,980 people (95% CI 2,899,260–4,088,700), of whom 3,029,280 people do not use any spectacles.

Conclusion : The burden of RE and presbyopia is substantial in Bangladesh. Improving awareness and availability of refraction services is required to correct REs and presbyopia in Bangladesh.     

Addressing refractive error visual impairment: volunteer organisations' alignment with Vision 2020 and public health principles

Background: Eye care professionals have been making short visits to developing countries for decades in an effort to reduce visual impairment caused by refractive error. A 2006 survey revealed that volunteer organisations were not working within the Vision 2020 framework. Recommendations were made for volunteer organisations that would better align their work with accepted Vision 2020 and public health principles. Methods: This study re‐evaluates the alignment of volunteer organisations with Vision 2020 and public health principles. To determine their philosophies and methods, a web‐based survey was sent to 89 volunteer organisations identified from an internet search. Results: The response rate was 48 per cent. Many (70.7 per cent) organisations exclusively mention direct service provision in their statement of purpose, often provided by student volunteers (75.6 per cent). A few (19.5 per cent) provide short training in refraction, not necessarily following best principles. The majority (82.1 per cent) dispenses recycled spectacles and many use medications not on national essential drug lists. Few attempt to follow aid effectiveness principles with only 26.8 per cent stating they follow Vision 2020 country plans. Overall, as in 2006, the work of these organisations is largely not in alignment with Vision 2020 and public health principles. Conclusion: Organisations interested in decreasing visual impairment due to refractive error in the developing world are encouraged to transition to organisations that not only recognise but also implement public health principles. This should include reprioritisation of their work to developing human resources and infrastructure, determining the burden and causes of disease, assisting in the training of mid‐level personnel and providing professional and community education, collaborating via partnerships, discontinuing the use of recycled spectacles and inappropriate medications, and evaluating their outcomes. Following these recommendations as well as creating a better alignment with public health principles in general will increase the likelihood that their programs will be effective in decreasing visual impairment due to refractive error in the developing world.     

Uncorrected Refractive Error and Presbyopia among Junior High School Teachers in Jakarta,Indonesia

Abstract

Purpose: To report on the frequency of observed refractive and accommodative errors among junior high school teachers in Jakarta, Indonesia, who participated in a Helen Keller International screening, refraction and spectacle distribution program.

Methods: A total of 965 teachers from 19 schools were eligible for screening; those with uncorrected distance visual acuity (VA) ≤6/12-3 and teachers ≥35 years old with uncorrected end-point print size >Jaeger (J) 6 were referred. Autorefraction and subjective refraction were performed for teachers with confirmed decreased VA. Refractive error was considered present if sphere ≤?0.75 diopters (D), sphere ≥+0.25D or cylinder ≤?0.50D resulted in ≥2 lines of improvement in VA. Presbyopia was considered present if an end-point print size >J6 improved by ≥1 optotype with the use of a lens ≥+1.00D.

Results: Overall, 866 teachers were screened (89.7% of those eligible) with complete screening data available for 858 (99.0%), among whom 762 failed screening. Distance refraction data were available for 666 of 762 (87.4%) and near refraction data for 520 of 686 (75.8%) teachers who failed screening. Of those screened, 76.2?±?9.0% of teachers had refractive and/or accommodative error and 57.1?±?7.6% had uncorrected refractive and/or accommodative error. Overall and uncorrected distance refractive error affected 44.2?±?3.7% and 36.0?±?3.6%, respectively; overall and uncorrected presbyopia affected 66.4?±?8.1% and 41.0?±?6.6%, respectively.

Conclusion: As defined in this program, refractive and accommodative errors were common among teachers in Jakarta.     

儿童盲和低视力的病因与屈光状态及远用助视器康复研究

目的：分析儿童盲和低视力的病因、屈光状态、屈光矫正和配用光学远用助视器矫正后的视力情况。

方法：选取2015-12/2018-04我科门诊接诊及盲校筛查的6～16岁低视力儿童和盲童212例422眼,通过相关检查明确病因和屈光状态,对部分患儿进行屈光矫正和光学远用助视器验配矫正,分析矫正后视力情况。

结果：儿童盲和低视力病因以先天性和遗传性眼病为主,本组病例中先天性白内障是首位原因(19.3%),低视力屈光不正以轻中度远视和近视多见(65.3%),屈光矫正后脱盲率(26.4%)和脱残率(14.6%)均低于联合远用助视器验配矫正后的脱盲率(58.3%)和脱残率(91.1%),差异均有统计学意义(P<0.01)。

结论：儿童盲和低视力病因复杂,应加强预防和筛查工作,低视力儿童应常规进行屈光矫正并配合使用远用助视器矫正,以利获得满意的康复效果。     

Criteria for prescribing optometric interventions: literature review and practitioner survey

The core function of optometrists is the prescribing of refractive corrections, yet a literature review revealed a lack of evidence-based research on criteria for determining when a refractive correction is required. The reported criteria used by practising optometrists were investigated using a questionnaire to survey prescribing habits for borderline hypermetropia, presbyopia, astigmatism, and horizontal and vertical heterophoria. Thirty-eight questionnaires were returned and the results analysed. We calculated the 'cut off' point above which the anomaly would be corrected over 50% of the time that it was encountered. There was a large variation for each category, but it was clear that the presence or absence of symptoms was an important factor for most optometrists when deciding whether to correct a small error. It was found that for symptomatic patients, most optometrists would correct an anomaly if it reached: +1.00 D of hypermetropia, a reading addition of +0.75 D for presbyopia, -0.75 DC of astigmatism, 1.5 prism dioptres (Delta) of horizontal aligning prism, and 1 Delta of vertical dissociated heterophoria. For asymptomatic patients, optometrists would not correct any of the hypermetropic anomalies or heterophorias that were specified in our questionnaire. However most would correct a presbyopic error of +1.50 D or above, or an astigmatic error of -1.50 DC or above, even in the absence of symptoms. These results were compared with previously published guidelines.     

Public sector refraction and spectacle dispensing in low-resource countries of the Western Pacific

Background:  Given that uncorrected refractive error is a frequent cause of vision impairment, and that there is a high unmet need for spectacles, an appraisal of public sector arrangements for the correction of refractive error was conducted in eight Pacific Island countries.
Methods:  Mixed methods (questionnaire and semi-structured interviews) were used to collect information from eye care personnel (from Fiji, Papua New Guinea, Solomon Islands, Vanuatu, Cook Islands, Samoa, Tonga and Tuvalu) attending a regional eye health workshop in 2005.
Results:  Fiji, Tonga and Vanuatu had Vision 2020 eye care plans that included refraction services, but not spectacle provision. There was wide variation in public sector spectacle dispensing services, but, except in Samoa, ready-made spectacles and a full cost recovery pricing strategy were the mainstay. There were no systems for the registration of personnel, nor guidelines for clinical or systems management. The refraction staff to population ratio varied considerably. Solomon Islands, Tuvalu and Vanuatu had the best coverage by services, either fixed or outreach. Most services had little promotional activity or community engagement.
Conclusions:  To be successful, it would seem that public sector refraction services should answer a real and perceived need, fit within prevailing policy and legislation, value, train, retain and equip employees, be well managed, be accessible and affordable, be responsive to consumers, and provide ongoing good quality outcomes. To this end, a checklist to aid the initiation and maintenance of refraction and spectacle systems in low-resource countries has been constructed.     

Costs of Eye Care Services: Prospective Study from a Faith-based Hospital in Zambia

Abstract

Purpose: To estimate the mean costs of cataract surgery and refractive error correction at a faith-based eye hospital in Zambia.

Methods: Out-of-pocket expenses for user fees, drugs and transport were collected from 90 patient interviews; 47 received cataract surgery and 43 refractive error correction. Overhead and diagnosis-specific costs were determined from micro-costing of the hospital. Costs per patient were calculated as the sum of out-of-pocket expenses and hospital costs, excluding user fees to avoid double counting.

Results: From the perspective of the hospital, overhead costs amounted to US$31 per consultation and diagnosis-specific costs were US$57 for cataract surgery and US$36 for refractive error correction. When including out-of-pocket expenses, mean total costs amounted to US$128 (95% confidence interval [CI] US$96--168) per cataract surgery and US$86 (95% CI US$67--118) per refractive error correction. Costs of providing services corresponded well with the user fee levels established by the hospital.

Conclusion: This is the first paper to report on the costs of eye care services in an African setting. The methods used could be replicated in other countries and for other types of visual impairments. These estimates are crucial for determining resources needed to meet global goals for elimination of avoidable blindness.     

The refractive status and vision profile: a questionnaire to measure vision-related quality of life in persons with refractive error

OBJECTIVE/BACKGROUND: To describe the Refractive Status and Vision Profile (RSVP), a questionnaire that measures self-reported vision-related health status (symptoms, functioning, expectations, concern) in persons with refractive error. DESIGN: Cross-sectional study by survey. PARTICIPANTS: The RSVP was self-administered by 550 participants with refractive error (or history of refractive surgery) recruited from five refractive surgery practices and one optometric practice. Information on refraction, uncorrected and best-corrected visual acuity, and history of refractive surgery was obtained from physicians' records. METHODS: Internal consistency, test-retest reliability, agreement with global measures of vision (criterion validity), discriminant validity, content validity, and construct validity (associations of scale scores with patient status variables) were assessed using Cronbach's alpha, Spearman rank correlations, factor analysis, and multitrait analysis. OUTCOME MEASURES: Scores on the overall RSVP scale (S) and on eight RSVP subscales (functioning, driving, concern, expectations, symptoms, glare, optical problems, problems with corrective lenses) were calculated based on 42 items. RESULTS: Cronbach's alpha was 0.92 for S and ranged from 0.70 to 0.93 for RSVP subscales, indicating good internal consistency. Satisfaction with vision was more strongly associated with S than with refractive error or with visual acuity. Individuals with more refractive error had significantly lower (worse) scores for S and for subscales concern, functioning, driving, optical problems, and glare. Scores for S and for subscales concern, functioning, optical problems, and driving remained significantly associated with satisfaction with vision after adjustment for age, gender, corrective lens type, and refractive error. CONCLUSIONS: The RSVP measures a range of visual, functional, and psychologic impacts of refractive error that are likely to be important to patients. The RSVP would be a useful tool for evaluating interventions for correction of refractive error and may be useful for assessing refractive surgery candidates in clinical practice.     

Functional presbyopia in a rural Kenyan population: the unmet presbyopic need

Background: Presbyopia is the most common reason for requiring spectacles in low‐income regions, although the unmet need for presbyopic spectacles in these regions is very high. The aim of this study was to estimate the prevalence of presbyopia, and the functional impairment and spectacle use among persons with presbyopia in a rural Kenyan population. Methods: A cross‐sectional study was carried out in the Rift Valley, Kenya. Clusters were selected through probability‐proportionate to size sampling, and people aged ≥50 years within the clusters were identified through compact segment sampling. Within the context of this survey, 130 eligible participants were selected for interview and underwent near‐vision testing. Functional presbyopia was defined as requiring at least +1.00 dioptre in order to read the N8 optotype at a distance of 40 cm in the participant's usual visual state. Participants were corrected to the nearest 0.25 dioptre in order to see N8. Unmet and met presbyopic need, and presbyopic correction coverage were calculated. Results: Functional presbyopia was found in 111 participants (85.4%). Mean age was lower in those with presbyopia (64.1 years vs. 71.5 years, P = 0.004). Increasing degree of addition required to see N8 was significantly associated with increased difficulty with reading (P = 0.04), sewing (P = 0.03), recognizing small objects (P = 0.02) and harvesting grains (P = 0.05). Among participants with functional presbyopia, 5.4% wore reading glasses and 25.2% had prior contact with an eye care professional. The unmet presbyopic need was 80.0%, met presbyopic need was 5.4% and presbyopic correction coverage was 6.3%. Cost was cited as the main barrier to spectacle use in 62% of participants with presbyopia. Conclusion: In low‐income regions, there is a high prevalence of uncorrected presbyopia, which is associated with near‐vision functional impairment. Provision of spectacles for near vision remains a priority in low‐income regions.     

老视屈光手术的个体化途径

老视手术是矫治老视的有效方法之一。随着手术技术的不断提高,临床经验不断积累,老视屈光手术的有效性及安全性得到了明显提升,但远期稳定性仍需改善。目前,激光矫正术是老视屈光手术的主要途径,屈光晶状体植入术、Inlay植入术成为激光手术的重要补充。个体化的手术术式是今后的发展方向。     

What we know and understand about presbyopia

The major theories for presbyopia are reviewed. These date from the very earliest hypotheses to current ideas and encompass both rheological (mechanical or elastic) and optical factors. Experimental findings are presented to support or refute the theories. The onset and rate of progression of presbyopia is shown to have multifactorial influences and a substantial contribution comes from an age-related change in the refractive index gradient of the lens cortex. (Clin Exp Optom 1993; 76: 3: 83–90)     

Psychometric properties of the National Eye Institute-Refractive Error Quality of Life instrument

OBJECTIVE: To estimate the psychometric properties of a vision-targeted measure of health-related quality of life, the National Eye Institute-Refractive Error Quality of Life survey (NEI-RQL), which includes 13 scales designed to assess the impact of refractive error and its correction on day-to-day life. DESIGN: Cross-sectional survey. PARTICIPANTS: The NEI-RQL was self-administered by 667 myopes, 380 hyperopes, and 114 emmetropes recruited from the practices of 6 medical centers. All participants had near and distance visual acuity of 20/32 or better in the worse eye while benefiting from their current method for correction of refractive error (glasses, contact lens, refractive surgery). METHODS: Mean scores, standard deviations, internal consistency reliability, and test-retest intraclass correlations were estimated for the NEI-RQL scales. Item discrimination was assessed by item-scale correlations. Construct validity was evaluated by assessing the sensitivity of scale scores to type of refractive error, type of refractive error correction, and spherical equivalent. Construct validity of the NEI-RQL was compared to those of the Medical Outcomes Study 36-item short-form health survey (SF-36) and the National Eye Institute Vision Functioning Questionnaire (NEI VFQ-25) in a random subsample of respondents. MAIN OUTCOME MEASURES: The 13 NEI-RQL scales-clarity of vision, expectations, near vision, far vision, diurnal fluctuations, activity limitations, glare, symptoms, dependence on correction, worry, suboptimal correction, appearance, and satisfaction with correction. RESULTS: Emmetropes tended to score significantly better on the NEI-RQL scales than myopes and hyperopes. The method of refractive error correction was also associated with NEI-RQL scores. In addition, the NEI-RQL multi-item scales accounted for 29% of the variance in the NEI-RQL satisfaction with correction item beyond that explained by the SF-36 and the NEI VFQ-25. CONCLUSION: These results support the reliability and construct validity of the NEI-RQL. The instrument appears to be useful for comparisons of people with different types of correction for refractive error.     

Refractive cataract surgery

Cataract surgery is the most commonly performed refractive procedure in the world today. Improvements in the calculation of intraocular lens power and design have allowed complete spherical correction of preexisting refractive error with intraocular lens implantation. Advances in incision construction have improved the refractive results of cataract surgery by minimizing surgically induced astigmatism. Astigmatism and pseudophakic presbyopia continue as the primary indications for spectacle correction following cataract surgery. Improvements in the technique of correcting preexisting astigmatism with cataract surgery have improved the uncorrected visual outcome of cataract surgery. The application of these advances in technology over the past year has demonstrated that full refractive correction of the cataract patient is now possible.     

Current status of cataract blindness and Vision 2020: the right to sight initiative in India

Background:

India is a signatory to the World Health Organization resolution on Vision 2020: The right to sight. Efforts of all stakeholders have resulted in increased number of cataract surgeries performed in India, but the impact of these efforts on the elimination of avoidable blindness is unknown.

Aims:

Projection of performance of cataract surgery over the next 15 years to determine whether India is likely to eliminate cataract blindness by 2020.

Materials and Methods:

Data from three national level blindness surveys in India over three decades, and projected age-specific population till 2020 from US Census Bureau were used to develop a model to predict the magnitude of cataract blindness and impact of Vision 2020: the right to sight initiatives.

Results:

Using age-specific data for those aged 50+ years it was observed that prevalence of blindness at different age cohorts (above 50 years) reduced over three decades with a peak in 1989. Projections show that among those aged 50+ years, the quantum of cataract surgery would double (3.38 million in 2001 to 7.63 million in 2020) and cataract surgical rate would increase from 24025/million 50+ in 2001 to 27817/million 50+ in 2020. Though the prevalence of cataract blindness would decrease, the absolute number of cataract blind would increase from 7.75 million in 2001 to 8.25 million in 2020 due to a substantial increase in the population above 50 years in India over this period.

Conclusions:

Considering existing prevalence and projected incidence of cataract blindness over the period 2001-2020, visual outcomes after cataract surgery and sight restoration rate, elimination of cataract blindness may not be achieved by 2020 in India.