Situation analysis on the integration of refractive error services provided by optometrists into the national health services in Kenya.

INTRODUCTION: Even though the burden of uncorrected refractive error could potentially be addressed through innovative and cost-effective approaches, integration of the services into the National Health Services (NHS) is desirable. However, minimal information exists on the current situation warranting the need for evidence about the integration of refractive error service provided by optometrists into the national health services in Kenya. METHODS: A situation analysis of the Kenyan refractive error services provided by optometrists within the NHS was undertaken based on access to service delivery, service coverage, and human resource. A strengths, weaknesses, opportunities, and threats analysis was undertaken based on the existent evidence to identify the core factors that could potentially facilitate or hinder the integration of refractive error services provided by optometrists within the National Health Services. The proportion of optometrists to be integrated in the NHS was estimated based on the minimum ratios recommended by the World Health Organization. RESULTS: A section of tertiary and secondary healthcare facilities in Kenya have specific services to address refractive errors within the NHS with most facilities lacking such services. Treatment of refractive error occurs at the level of eye care general services. There are 11,547 health facilities offering primary care services in Kenya. However, none of them offers refractive error services and only a section of facilities offering county health referral services provides eye care services which is limited to refraction without provision of spectacles. The existing workforce comprises of ophthalmologists, optometrists and ophthalmic clinical officers, together with nurses and other general paramedical assistants. Optometrists, ophthalmologists and ophthalmic clinical officers are allowed to undertake refraction. However, optometrists majorly practices in the private sector. Centralization of eye care services in urban areas, weak referral systems, and a shortage in the workforce per population was observed. CONCLUSIONS: The Kenyan NHS should advocate for primary care and reorient the current hospital-based delivery approach for refractive error services. This is attributed to the fact that provision of refractive error services at primary care remains effective and efficient and could translate to early detection of other ocular conditions. The existing human resources in the eye health ecosystem in Kenya should maximize their efforts towards addressing uncorrected refractive error and optometrists should be integrated into the NHS.

Patterns in refractive error and treatment delay in keratoconus-An Australian study.

Keratoconus is the most common primary corneal ectasia and is associated with significant morbidity. In its early stages, keratoconus is often asymptomatic, making the identification of subclinical disease challenging. Refractive error is a parameter that is documented at most routine optometry visits, yet interestingly, changes in refraction of keratoconic patients over time have not yet been studied and compared with the general population. Early diagnosis of keratoconus facilitates timely referral for treatments such as corneal collagen cross-linking, which has been shown to slow disease progression. In this context, documenting delays between initial presentation to the optometrist and referral for collagen-cross-linking as well as comparing the trends in visual acuity and refractive error between keratoconic and non-keratoconic patients over time are particularly relevant.

Impact of Vision Impairment and Ocular Morbidity and Their Treatment on Quality of Life in Children: A Systematic Review.

TOPIC: This review summarizes existing evidence of the impact of vision impairment and ocular morbidity and their treatment on children's quality of life (QoL). CLINICAL RELEVANCE: Myopia and strabismus are associated with reduced QoL among children. Surgical treatment of strabismus significantly improves affected children's QoL. METHODS: We conducted a systematic review and meta-analysis by screening articles in any language in 9 databases published from inception through August 22, 2022, addressing the impact of vision impairment, ocular morbidity, and their treatment on QoL in children. We reported pooled standardized mean differences (SMDs) using random-effects meta-analysis models. Quality appraisal was performed using Joanna Briggs Institute and National Institutes of Health tools. This study was registered with the International Prospective Register of Systematic Reviews (identifier, CRD42021233323). RESULTS: Our search identified 29 118 articles, 44 studies (0.15%) of which were included for analysis that included 32 318 participants from 14 countries between 2005 and 2022. Seventeen observational and 4 interventional studies concerned vision impairment, whereas 10 observational and 13 interventional studies described strabismus and other ocular morbidities. Twenty-one studies were included in the meta-analysis. The QoL scores did not differ between children with and without vision impairment (SMD, -1.04; 95% confidence interval [CI], -2.11 to 0.03; P = 0.06; 9 studies). Myopic children demonstrated significantly lower QoL scores than those with normal vision (SMD, -0.60; 95% CI, -1.09 to -0.11; P = 0.02; 7 studies). Children with strabismus showed a significantly lower QoL score compared with those without (SMD, -1.19; 95% CI, -1.66 to -0.73; P < 0.001; 7 studies). Strabismus surgery significantly improved QoL in children (SMD, 1.36; 95% CI, 0.48-2.23; P < 0.001; 7 studies). No randomized controlled trials (RCTs) concerning refractive error and QoL were identified. Among all included studies, 35 (79.5%) were scored as low to moderate quality; the remaining met all quality appraisal tools criteria. DISCUSSION: Reduced QoL was identified in children with myopia and strabismus. Surgical correction of strabismus improves the QoL of affected children, which supports insurance coverage of strabismus surgery. Further studies, especially RCTs, investigating the impact of correction of myopia on QoL are needed. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Childhood Eye Examination in Primary Care.

Approximately 7% of children in the United States younger than 18 years have a diagnosed eye disorder, and 1 in 4 children between two and 17 years of age wears glasses. Routine eye examinations during childhood can identify abnormalities necessitating referral to ophthalmology, which optimizes children's vision through the early diagnosis and treatment of abnormalities. The U.S. Preventive Services Task Force recommends vision screening at least once in children three to five years of age to detect amblyopia or its risk factors to improve visual acuity. The American Academy of Family Physicians supports this recommendation. The American Academy of Pediatrics recommends screening starting at three years of age and at regular intervals in childhood, and that instrument-based screening (e.g., photoscreening, autorefraction) is an alternative to vision charts for testing visual acuity in patients three to five years of age. Eye examinations include visual acuity testing, external examinations, assessing ocular alignment and pupillary response, and assessing for opacities with the red reflex examination. Common abnormalities include refractive errors, amblyopia (reduction in visual acuity in one eye not attributable to structural abnormality), and strabismus (misalignment of the eye). Rare diagnoses include retinoblastoma (often detectable through loss of red reflex), cataracts (detectable by an abnormal red reflex), and glaucoma (often manifests as light sensitivity with corneal cloudiness and enlargement).

Distance spectacle-wearing habits in older patients in England.

PURPOSE: To report the proportion of older people in England who wear distance spectacles full time, part time and rarely, and to investigate factors that influence how much the distance vision (DV) correction is worn. METHODS: A two-part questionnaire investigating the spectacle-wearing habits of older people was developed and completed by 322 participants (age 72 years ±7.7, range 60-94). A subcohort of 209 DV correction wearers with a mean spherical equivalent (MSE) of <±4.00DS was selected for a logistic regression to investigate which factors influence how much the DV correction is used. RESULTS: In total, 43% of emmetropic, and 55% of pseudophakic, DV spectacle wearers wear their correction full time. Lens type, MSE and the age that participants first wore a DV correction significantly predicted DV correction wearing habit (adjusted R2 = 0.36), with lens type being the strongest predicting factor and progressive users wearing their spectacles 37% more than those using single vision lenses. CONCLUSIONS: Many patients appear to consider convenience more important than being spectacle independent at distance, with lens type the most significant influencing factor of how much those with low/moderate refractive error wear their distance correction. Many emmetropes and pseudophakes choose to wear their progressive or bifocal spectacles full time, and the emmetropia provided by cataract surgery does not provide independence from full-time spectacle wear for many patients. The optometrist has a key role in discussing both choice of spectacle lens correction and the refractive outcome options of cataract surgery with patients.

Refractive profile of children treated with intravitreal bevacizumab for retinopathy of prematurity.

Purpose: To study the refractive profile of children after they received intravitreal injection of bevacizumab for retinopathy of prematurity (ROP). Methods: The study was conducted at a tertiary eye care hospital in South India. ROP patients of more than 1 year of age, presenting to the Pediatric Ophthalmology Clinic and Retina Clinic and having history of treatment for type I ROP with intravitreal bevacizumab (IVB) or intravitreal bevacizumab and laser photocoagulation were included in the study. Cycloplegic refraction was done, and the refractive status was evaluated. The refractive status of age-matched, full-term children with uneventful perinatal and neonatal history was also recorded and compared to the study group. Results: Among 134 eyes of 67 study subjects, the major refractive error was myopia in 93 eyes (69.4%; spherical equivalent [SE] = -2.89 ± 3.1, range = -11.5 to -0.5 D). There were 75 eyes (56%) with low-to-moderate myopia; high myopia was seen in 13.4%, emmetropia in 18.7%, and hypermetropia in 11.9% of eyes. The majority of them (87%) had with-the-rule (WTR) astigmatism. In 134 eyes, the SE was -1.78 ± 3.2 (range = -11.5 to 4 D); the SE of the 75 eyes with low-to-moderate myopia was -1.53 ± 1.2 (range = -0.50 to -5 D). In the control group, the majority had emmetropia (91.8%). There was no significant association between the age at which IVB had been injected and the development of refractive errors (P = 0.078). The prevalence of low-to-moderate myopia was more than high myopia in patients with zone I and zone II ROP before treatment (60.0% and 54.5%, respectively). Conclusion: Myopia was the major refractive error seen in post-IVB pediatric patients. WTR astigmatism was more commonly seen. The age at which IVB injection had been given had no effect on the development of refractive errors.

[Enhancement Options after Lens and Corneal Refractive Surgery]. / Enhancement-Optionen nach Linsen- und refraktiver Hornhautchirurgie.

BACKGROUND: Modern preoperative diagnostics as well as current surgical techniques allow cataract and refractive surgery to deliver precise refractive results.Occasionally, unsatisfactory refractive and visual results occur despite all the care taken. In these cases, subsequent improvement is required to achieve the best final visual outcome. This article shows the therapeutic options for the treatment of residual refractive errors after lens and corneal refractive surgery. KEY MESSAGES: The causes of postoperative refractive errors after refractive laser- or lens-based procedures are very diverse and require extensive workup of the cause as well as an individual solution to achieve the desired result. Before any further surgical intervention, specific complications of the primary procedure as well as concomitant ocular diseases must be excluded or treated. The appropriate enhancement after keratorefractive surgery depends primarily on the type of primary surgery, residual stromal thickness, possible complications from the initial surgery, and the patient's personal preference. For enhancements using surface treatments, such as PRK, the use of mitomycin C is recommended for prophylaxis of haze formation. After lens surgery, for low-grade postoperative refractive errors (spherical and astigmatic), keratorefractive enhancements provide the most accurate results. For higher refractive errors, lens-based procedures can be used, with add-on IOLs being safer and more precise compared with one IOL exchange. Low astigmatisms can be successfully treated with LRI or keratorefractive surgery, but higher astigmatisms should be corrected with an IOL exchange in the early postoperative period and with an add-on IOL in the later postoperative period. IOL explantations should be performed very cautiously, especially in cases of pronounced capsular fibrosis, previous posterior capsulotomy, and existing weakness of the zonular apparatus.

Impact of an intervention for avoidable vision loss on visual function in the elderly-The Hyderabad Ocular Morbidity in Elderly Study (HOMES).

BACKGROUND/OBJECTIVES: To report the impact of interventions for avoidable vision impairment (VI) on the visual function of elderly residents in 'homes for the aged' in India. METHODS: Participants aged ≥60 years were recruited. A comprehensive eye examination was conducted by trained examiners and interventions were provided. Trained social investigators administered the Indian Vision Function questionnaire (INDVFQ) to assess visual function before and after the intervention (spectacles, cataract surgery or laser capsulotomy). Lower scores on IVFQ imply better visual function. VI was defined as presenting visual acuity worse than 6/18 in the better eye. VI due to cataract, uncorrected refractive errors, and posterior capsular opacification after cataract surgery were considered avoidable VI. RESULTS: The mean age of the participants (n = 613) was 73.8 years (standard deviation: 8.1 years) and 378 (62.2%) were women. 64/103 (62.1%) participants who had avoidable VI at baseline were evaluated after the intervention. Significant gains were observed in all four domains of visual function. There was a 14.9% improvement in mobility scores (33.8 versus 28.8; p = 0.03), a 19.9% improvement in the activity limitations score (36.8 versus 29.5; p < 0.01), a 10.9% improvement in the psychosocial impact score (41.1 versus 36.6; p < 0.01) and a 13.6% improvement in the visual symptoms score (49.2 versus 42.5 p < 0.01). Overall, the mean IVFQ score improved by 16.4% (47.6 versus 39.8; p < 0.01). CONCLUSION: Elderly individuals in residential care with avoidable VI had a significant improvement in visual function after relatively low-cost interventions such as spectacles and cataract surgery. Strategies are needed to provide these interventions for the elderly in 'homes for the aged' in India.

The contribution of intraocular lens calculation accuracy to the refractive error predicted at 10 years in the Infant Aphakia Treatment Study.

PURPOSE: To determine the relative contribution of intraocular lens (IOL) calculation accuracy and ocular growth variability to the long-term refractive error predicted following pediatric cataract surgery. METHODS: Pseudophakic eyes of children enrolled in the Infant Aphakia Treatment Study (IATS) were included in this study. Initial absolute prediction error (APE) and 10-year APE were calculated using the initial biometry, IOL parameters, postoperative refractions, and mean rate of refractive growth. The cohort was divided into children with a low-initial APE (≤1.0 D) and a high-initial APE ( >1.0 D). The 10-year APE was compared between the two groups using the Mann-Whitney U test. Linear regression was used to estimate the variability in prediction error explained by the initial IOL calculation accuracy. RESULTS: Forty-two children with IOL placement in infancy were included. Seventeen eyes had a low initial APE, and 25 eyes had a high initial APE. There was no significant difference in APE 10 years following surgery between individuals with a low initial APE (median, 2.67 D; IQR, 1.61-4.12 D) and a high initial APE (median, 3.45 D; IQR, 1.64-5.10 D) (P = 0.7). Initial prediction error could explain 12% of the variability in the prediction error 10 years following surgery. CONCLUSIONS: IOL calculation accuracy contributed minimally to the refractive error predicted 10 years after cataract surgery in the setting of high variability in the rate of refractive growth.

Effective lens position and pseudophakic refraction prediction error at 10½ years of age in the Infant Aphakia Treatment Study.

BACKGROUND: The refraction prediction error (PE) for infants with intraocular lens (IOL) implantation is large, possibly related to an effective lens position (ELP) that is different than in adult eyes. If these eyes still have nonadult ELPs as they age, this could result in persistently large PE. We aimed to determine whether ELP or biometry at age 10½ years correlated with PE in children enrolled in the Infant Aphakia Treatment Study (IATS). METHODS: We compared the measured refraction of eyes randomized to primary IOL implantation to the "predicted refraction" calculated by the Holladay 1 formula, based on biometry at age 10½ years. Eyes with incomplete data or IOL exchange were excluded. The PE (predicted - measured refraction) and absolute PE were calculated. Measured anterior chamber depth (ACD) was used to assess the effect of ELP on PE. Multiple regression analysis was performed on absolute PE versus axial length, corneal power, rate of refractive growth, refractive error, and best-corrected visual acuity. RESULTS: Forty-three eyes were included. The PE was 0.63 ± 1.68 D; median absolute PE, 0.85 D (IQR, 1.83 D). The median absolute PE was greater when the measured ACD was used to calculate predicted refraction instead of the standard A-constant (1.88 D [IQR, 1.72] D vs 0.85 D [IQR, 1.83], resp. [P = 0.03]). Absolute PE was not significantly correlated with any other parameter. CONCLUSIONS: Variations in ELP did not contribute significantly to PE 10 years after infant cataract surgery.

Dioptric power and refractive behaviour: a review of methods and applications.

Myopia is a global healthcare concern and effective analyses of dioptric power are important in evaluating potential treatments involving surgery, orthokeratology, drugs such as low-dose (0.05%) atropine and gene therapy. This paper considers issues of concern when analysing refractive state such as data normality, transformations, outliers and anisometropia. A brief review of methods for analysing and representing dioptric power is included but the emphasis is on the optimal approach to understanding refractive state (and its variation) in addressing pertinent clinical and research questions. Although there have been significant improvements in the analysis of refractive state, areas for critical consideration remain and the use of power matrices as opposed to power vectors is one such area. Another is effective identification of outliers in refractive data. The type of multivariate distribution present with samples of dioptric power is often not considered. Similarly, transformations of samples (of dioptric power) towards normality and the effects of such transformations are not thoroughly explored. These areas (outliers, normality and transformations) need further investigation for greater efficacy and proper inferences regarding refractive error. Although power vectors are better known, power matrices are accentuated herein due to potential advantages for statistical analyses of dioptric power such as greater simplicity, completeness, and improved facility for quantitative and graphical representation of refractive state.

Population-based assessment of prevalence of spectacle use and effective spectacle coverage for distance vision in Andhra Pradesh, India - Akividu Visual Impairment Study.

CLINICAL RELEVANCE: Effective spectacle coverage is a useful indicator to assess the coverage of refraction services in a given region. We found a low coverage in the Akividu region suggesting a need to develop effective refraction services. BACKGROUND: To assess the prevalence of spectacle use and effective spectacle coverage for distance vision among people aged 40 years and older in the Indian state of Andhra Pradesh. METHODS: A population-based cross-sectional survey was carried out in the Akividu region in West Godavari and Krishna districts. The study teams visited selected households and conducted eye examinations in the selected clusters. A structured questionnaire was used to collect information on spectacle use. 'Met Need' was defined as unaided VA worse than 6/12 but improved to 6/12 or better with their current spectacles. 'Unmet Need' was defined as unaided VA worse than 6/12 but improved to 6/12 with pinhole, among those not using spectacles. The 'Under-met Need' was defined as aided VA worse than 6/12 but improving with pinhole to 6/12 or better. Based on these definitions, Effective Refractive Error Coverage (e-REC) is calculated as: e-REC (%) s = ((met need)/(met need + under-met need + unmet need)) X100. RESULTS: Of 3,000 enumerated from 60 clusters, 2,587 (86.2%) participants were examined. The prevalence of current spectacle use was 43.1% (95% CI:41.2-45.0). The e-REC was 37.4%. It was also lower in men compared to women and among those without any education. Participants who had cataract surgery in either eye had similar e-REC compared to those who were not operated. CONCLUSION: Though spectacle use was found to be high, there is a still large unmet need for refractive correction for distance. Effective service delivery models to provide refraction and spectacle dispensing services are needed to achieve universal eye health coverage in the region.

Item banks for measurement of refractive error-specific quality of life.

PURPOSE: To evaluate the psychometric properties of refractive error-specific quality of life (QoL) item banks and assess their performance using computerised adaptive testing (CAT) simulations. METHODS: In this cross-sectional study a 392-item questionnaire, grouped under 11 QoL domains, was interviewer-administered to 305 people with refractive error [mean age ± S.D., 30.5 ± 14.1 (range (18 to 83) years; male, 50.5%; mean ± S.D. spherical equivalent refractive error -2.4 ± 2.9 (range: -15.0 to +11.0) Dioptres; spectacles (n = 257), contact lens (n = 37), refractive surgery (n = 25), uncorrected refractive error (n = 57)]. Rasch analysis was conducted on each QoL domain using the Andrich rating scale model to investigate parameters including response category functioning, person- and item-reliability, infit and outfit statistics, unidimensionality, targeting, differential item functioning and local item dependency. The resulting item banks underwent CAT simulations in 1,000 cases with 'high' and 'moderate' precision stopping rules. RESULTS: Rasch analysis iterations resulted in 13 refractive error-specific item banks (Convenience, Health concerns, Economic, Activity limitation, Mobility, Emotional, Social, Visual symptoms frequency, Visual symptoms severity, Visual symptoms bothersome, Comfort symptoms frequency, Comfort symptoms severity and Comfort symptoms bothersome), containing a total of 366 items. The item banks had good psychometric properties including satisfactory measurement precision, infit and outfit statistics and unidimensionality. In CAT simulations, the mean number of items required to achieve high and moderate measurement precision was 9.4 and 4.7, respectively. CONCLUSION: Overall, refractive error-specific QoL item banks show promise in their ability to comprehensively and precisely evaluate a range of quality of life parameters. These items banks when administered using a CAT system offer unique outcome tools for implementation in clinical trials, healthcare and research.

Femtosecond Lasers in Cornea & Refractive Surgery.

Since the introduction of femtosecond laser (FS) systems for corneal flap creation in laser-assisted in-situ keratomileusis there have been numerous applications for FS laser in corneal surgery. This manuscript details the utility of FS lasers in corneal surgical procedures including refractive laser surgeries, intracorneal ring segment tunnels, presbyopic treatments, and FS-assisted keratoplasty. We also review the role of FS lasers in diagnostic procedures such as two photon excitation fluorescence and second harmonic generation.

Barriers to treatment-seeking for impairment of vision among elderly persons in a resettlement colony of Delhi: A population-based cross-sectional study.

Background & objectives: Uncorrected refractive error and cataract are the two most common causes of impairment of vision among elderly persons, and both are treatable. Treatment-seeking in patients is driven by symptom (decreased vision) rather than any anatomical or physiological measurement. The objective of this study was to evaluate the treatment-seeking behavior and barriers to treatment-seeking among elderly persons with impairment of vision in an urban resettlement colony of New Delhi, India. Methods: This community-based, cross-sectional study was conducted among 604 persons aged ≥60 yr selected by the simple random sampling. House-to-house visit was done, and a self-developed pretested semi-structured interview schedule was used to collect socio-demographic information, treatment-seeking behaviour and barriers to treatment-seeking. Results: Majority of participants reported impairment of vision (84%); 16.5 per cent of them did not visit any healthcare facility for their vision problem. Lack of felt need (48.1%) was the most common barrier to visiting healthcare facility. Of the 401 participants who gave a history of being prescribed spectacles, 277 (69%) used spectacles. Discomfort, lack of improvement in vision and lack of felt need were the most common reasons cited for non-usage. Among 300 participants who gave a history of cataract, 61 (20.3%) had not undergone cataract surgery. Lack of felt need was the most common barrier to cataract surgery. Interpretation & conclusions: A substantial proportion of elderly persons in the urban community have impairment of vision. Lack of felt need was the main reason for not visiting healthcare facility. As quality of spectacles was an important reported deterrent to use of spectacles, provision of appropriate refraction services and low-cost, good quality spectacles would be important.

Intraocular Lens Power Calculations in Eyes with Previous Corneal Refractive Surgery: Review and Expert Opinion.

Intraocular lens (IOL) power calculations are less accurate in eyes that have undergone corneal refractive surgery. A wide range of methods have been proposed. We reviewed the methods and outcomes of IOL power calculations in eyes with previous LASIK, excimer laser photorefractive keratectomy (PRK), or radial keratotomy (RK). The PubMed database was searched for articles that (1) discuss methods and outcomes of IOL power calculation in eyes with previous corneal refractive surgery and (2) evaluate the outcomes of toric, multifocal, or extended depth-of-focus (EDOF) IOLs in these eyes. We excluded review articles, case reports or case studies, and non-English reports. Seventy full-text articles were included in this review. Three categories of methods exist based on whether and how they use historical data acquired before the corneal refractive surgery. The American Society of Cataract and Refractive Surgery (ASCRS) postrefractive IOL calculator incorporates many commonly used methods. In eyes with previous myopic LASIK or PRK, hyperopic LASIK or PRK, and RK, 0% to 85%, 38.1% to 71.9%, and 29% to 87.5% of eyes, respectively, showed refractive prediction errors within ±0.5 diopter (D); in eyes with toric IOL implantation that met certain inclusion criteria, 80%, 84%, and 69% of eyes, respectively, achieved postoperative astigmatism of 0.50 D or less. Intraocular lenses with negative spherical aberration (SA) will reduce the positive corneal spherical aberration induced in eyes by myopic LASIK or PRK or by RK. Intraocular lenses with 0 SA on average best match corneal SA in eyes with prior hyperopic LASIK or PRK. Studies have reported excellent outcomes of postrefractive eyes implanted with multifocal or EDOF IOLs; however, corneal topographic enrollment criteria were not specified. Despite availability of new measurement technologies and development of new IOL calculation formulas, further advances are needed to improve outcomes of cataract surgery in eyes that have undergone corneal refractive surgery. Tools like the ASCRS postrefractive IOL calculator are useful for the clinician by incorporating a variety of formulas. Toric, EDOF, and multifocal IOLs may provide excellent outcomes in selected cases that meet certain corneal topographic criteria.