Cycloplegic Subjective Refraction Research Articles

Method comparison and overview of refractive measurements in children: implications for myopia management

ObjectiveThis study investigated the agreement between objective wavefront-based refraction and subjective refraction in myopic children. It also assessed the impact of cyclopentolate and refraction levels on the agreement.MethodsA total of...

The Impact of Vergence Dysfunction on Myopia Control in Children Wearing Defocus Spectacle Lenses.

To investigate the impact of vergence dysfunction on myopia progression in children with Defocus incorporated multiple segments (DIMS) spectacle lenses. We retrospectively enrolled children prescribed DIMS spectacle lenses to slow myopic progression. Baseline vergence dysfunction was determined according to phoria at distance and near. Axial length (AL) measurement and cycloplegic subjective refraction were performed before fitting the lenses and at six-month and one-year follow-ups. The six-month and one-year AL and spherical equivalent (SE) change from baseline were calculated and compared in subgroups stratified with the type of vergence dysfunction. Two hundred and ninety-two myopic children were included. Significant AL elongation and SE progression were observed at six months and one year (P < 0.05 for all comparisons). Multiple regression demonstrated that AL elongation at six months (P < 0.001) and one year (P < 0.001) was negatively correlated with age, and SE progression at six months was associated with age (P = 0.002). The AL elongation at six months in children with convergence excess was significantly greater than in normal myopic subjects (P = 0.011) and subjects with convergence insufficiency (P = 0.008), divergence excess (P = 0.007), divergence insufficiency (P = 0.024) and basic esophoria (P = 0.048) at six months. The present research demonstrated that vergence dysfunction influences myopia progression for myopic children with DIMS, and the children with convergence excess suffer from the greatest myopia progression among different types of vergence dysfunction.

The impact of accommodation function on the difference between noncycloplegic and cycloplegic refraction in adult myopes.

To investigate the impact of accommodation function on the difference between cycloplegic and noncycloplegic subjective and automatic refraction in adult myopes. Myopic patients between 18 and 50 years old evaluated at Peking University Third Hospital who underwent cycloplegic and noncycloplegic automatic and subjective refraction were enrolled. Accommodation function, including negative and positive relative accommodation (PRA/NRA) and accommodation response (binocular cross cylinder, BCC) was examined. Of the 3268 individuals enrolled, the mean age was 27.3 ± 6.9 years, and 34.8% of participants were male. The noncycloplegic spherical equivalent (SE) was 0.23 ± 0.29 D and 0.64 ± 0.61 D more myopic than cycloplegic subjective and automatic refraction. Adjusting for associated factors, participants with at least 0.50 D of more myopia SE refraction by noncycloplegic subjective refraction were more likely to be older (odds ratio [OR], 1.029; 95% confidence interval [CI], 1.013-1.045) and with insufficient (OR, 1.514; 95% CI, 1.093-2.096) and excessive (OR, 2.196; 95% CI, 1.538-3.137) NRA value. The automatic refraction SE difference of at least 1.00 D more myopia was more likely to be found in individuals with older age (OR, 1.036; 95% CI, 1.022-1.050) and accommodative lead (OR, 1.255; 95% CI, 1.004-1.568). A quarter of adult myopes had at least 0.50 and 1.00 D of subjective and automatic SE difference with cycloplegia. The accommodation function significantly affects the difference between cycloplegic and noncycloplegic refraction. Investigating the differences in refraction measurement guarantees the proper use of cycloplegia in adults for myopia correction.

Axial length shortening in myopic children with Stickler syndrome after repeated low-level red-light therapy.

To report the myopia-controlling effect of repeated low-level red-light (RLRL) therapy in patients with Stickler syndrome (STL), an inherited collagenic disease typically presenting with early onset myopia. Three STL children, aged 3, 7, and 11y, received RLRL therapy throughout the follow-up period of 17, 3, and 6mo, respectively after exclusion of fundus anomalies. Data on best-corrected visual acuity (BCVA), intraocular pressure, cycloplegic subjective refraction, ocular biometrics, scanning laser ophthalmoscope, optical coherence tomography, genetic testing, systemic disease history, and family history were recorded. At the initiation of the RLRL therapy, the spherical equivalent (SE) of 6 eyes from 3 patients ranged from -3.75 to -20.38 D, axial length (AL) were from 23.88 to 30.68 mm, and BCVA were from 0.4 to 1.0 (decimal notation). Myopia progression of all six eyes slowed down after RLRL therapy. AL in five out of the six eyes shortened -0.07 to -0.63 mm. No side effects were observed. Three cases of STL whose progression of myopic shift and AL elongation are successfully reduced and even reversed after RLRL therapy.

Refractive error correction among urban and rural school children using two self-adjustable spectacles

ObjectiveSelf-refracting spectacles (SRSs) have different optical and mechanical designs, which may affect the refractive outcome, depending on the experience of the end user. This study compared the performance of two...

Binocular Dynamic Visual Acuity in Eyeglass-Corrected Myopic Patients

Current clinical visual assessment mainly focuses on static vision. However, static vision may not sufficiently reflect real-life visual function as moving optotypes are frequently observed daily. Dynamic visual acuity (DVA) might reflect real-life situations better, especially when objects are moving at high speeds. Myopia impacts static uncorrected distance visual acuity, conveniently corrected with eyeglasses. However, due to peripheral defocus and prism effects, eyeglass correction might affect DVA. The present research demonstrates a standard method to examine eyeglass-corrected DVA in myopia patients, and aimed to explore the influence of eyeglass correction on DVA. Initially, standard subjective refraction was performed to provide the eyeglass prescription to correct the refractive error. Then, binocular distance vision-corrected DVA was examined using the object-moving DVA protocol. Software was designed to display the moving optotypes according to the preset velocity and size on a screen. The optotype was the standard logarithmic visual chart letter E and moves from the middle of the left to the right side horizontally during the test. Moving optotypes with randomized opening direction for each size are displayed. The subjects were required to identify the opening direction of the optotype, and the DVA is defined as the minimum optotype that subjects could recognize, calculated according to the algorithm of logarithmic visual acuity. Then, the method was applied in 181 young myopic subjects with eyeglass-corrected-to-normal static visual acuity. Dominant eye, cycloplegic subjective refraction (sphere and cylinder), accommodation function (negative and positive relative accommodation, binocular cross-cylinder), and binocular DVA at 40 and 80 degrees per second (dps) were examined. The results showed that with increasing age, DVA first increased and then decreased. When myopia was fully corrected with eyeglasses, a worse binocular DVA was associated with more significant myopic refractive error. There was no correlation between the dominant eye, accommodation function, and binocular DVA.

Binocular Dynamic Visual Acuity in Eyeglass-corrected Myopic Patients.

Current clinical visual assessment mainly focuses on static vision. However, static vision may not sufficiently reflect real-life visual function as moving optotypes are frequently observed daily. Dynamic visual acuity (DVA) might reflect real-life situations better, especially when objects are moving at high speeds. Myopia impacts static uncorrected distance visual acuity, conveniently corrected with eyeglasses. However, due to peripheral defocus and prism effects, eyeglass correction might affect DVA. The present research demonstrates a standard method to examine eyeglass-corrected DVA in myopia patients, and aimed to explore the influence of eyeglass correction on DVA. Initially, standard subjective refraction was performed to provide the eyeglass prescription to correct the refractive error. Then, binocular distance vision-corrected DVA was examined using the object-moving DVA protocol. Software was designed to display the moving optotypes according to the preset velocity and size on a screen. The optotype was the standard logarithmic visual chart letter E and moves from the middle of the left to the right side horizontally during the test. Moving optotypes with randomized opening direction for each size are displayed. The subjects were required to identify the opening direction of the optotype, and the DVA is defined as the minimum optotype that subjects could recognize, calculated according to the algorithm of logarithmic visual acuity. Then, the method was applied in 181 young myopic subjects with eyeglass-corrected-to-normal static visual acuity. Dominant eye, cycloplegic subjective refraction (sphere and cylinder), accommodation function (negative and positive relative accommodation, binocular cross-cylinder), and binocular DVA at 40 and 80 degrees per second (dps) were examined. The results showed that with increasing age, DVA first increased and then decreased. When myopia was fully corrected with eyeglasses, a worse binocular DVA was associated with more significant myopic refractive error. There was no correlation between the dominant eye, accommodation function, and binocular DVA.

Accuracy of Noncycloplegic Refraction for Detecting Refractive Errors in School-aged African Children.

Cycloplegia is often restricted in screening settings. Previous studies have evaluated noncycloplegic refraction for screening, but their data are not fully applicable to school-aged African children. This article adds to the literature by investigating this in school-aged African children. The purpose of this study was to evaluate the ability of noncycloplegic autorefraction (NCA) and noncycloplegic retinoscopy (NCR) to detect refractive errors in school-aged African children and quantify differences between noncycloplegic and cycloplegic refraction measures. Autorefraction and retinoscopy were performed on 150 children aged 6 to 15 years before and after cyclopentolate cycloplegia. Subjective refraction was performed by the same examiner after cycloplegia. Noncycloplegic and cycloplegic measurements were compared, and the data were assessed with receiver operating characteristic curves and Bland-Altman plots. With the exception of cylindrical vector J0 (P = .17) and J45 (P = .08) obtained with NCR, all mean measures of NCA and NCR significantly differed from mean cycloplegic subjective refraction measurements by -0.71 ± 0.67 (P ≤ .001; 95% confidence interval, -2.02 to +0.60) and -0.75 ± 0.68 (P ≤ .001; 95% confidence interval, -2.08 to +0.58), respectively. Mean spherical power between the two tests did not differ (NCA -NCR, mean bias of -0.037 ± 0.675 and 95% limits of agreement of -1.36 to 1.286; P = .51). The sensitivities for detecting any refractive error for NCR and NCA were 86.8 and 82.9%, respectively, and the specificities were 82.0% for NCR and 82.4% for NCA. Performance of both tests was excellent for myopia (area under the curve, >0.90; sensitivity, ≥90%) and similar (P = .13), but the specificities for detecting hyperopia were 78.0% for NCR and 80.0% for NCA. Noncycloplegic refraction may accurately detect astigmatism and myopia in this population but may elicit higher myopic values and lower hyperopic values than using cycloplegic refraction.

A randomized clinical trial using cyclopentolate and tropicamide to compare cycloplegic refraction in Chinese young adults with dark irises

BackgroundTo evaluate the necessity of cycloplegia for epidemiological studies of refraction in Chinese young adults (aged 17–22 years) with dark irises, and to compare the cycloplegic effects of 1% cyclopentolate and 0.5% tropicamide in them.MethodsA total of 300 young adults (108 males and 192 females) aged 17 to 22 years (mean 19.03 ± 1.01) were recruited from Tianjin Medical University from November 2019 to January 2020. Participants were randomly divided into two groups. In the cyclopentolate group, two drops of 1% cyclopentolate eye drop were administrated (one drop every 5 min), followed by autorefraction and subjective refraction 30 to 45 min later. In the tropicamide group, four drops of 1% Mydrin P (Tropicamide 0.5%, phenylephrine HCl 0.5%) eye drop were given (one drop every 5 min), followed by autorefraction and subjective refraction 20 to 30 min later. The participants and the examiners were masked to the medication. Distance visual acuity, intraocular pressure (IOP), non-cycloplegic and cycloplegic autorefraction (Topcon KR-800, Topcon Co. Tokyo, Japan), non-cycloplegic and cycloplegic subjective refraction and ocular biometry (Lenstar LS-900) were performed.ResultsThe values of spherical equivalent (SE) and sphere component were significantly different before and after cycloplegia in the cyclopentolate group and the tropicamide group (p < 0.05). The mean difference between noncycloplegic and cycloplegic autorefraction SE was 0.39 D (±0.66 D) in the cyclopentolate group and 0.39 D (±0.34 D) in the tropicamide group. There was no significant difference in the change of SE and sphere component after cycloplegia between the cyclopentolate group and the tropicamide group (p > 0.05). In each group, no significant difference was found between autorefraction and subjective refraction after cycloplegia (p > 0.05). We also found that more positive or less negative cycloplegic refraction was associated with the higher difference in SE in each group.ConclusionsCycloplegic refractions were generally more positive or less negative than non-cycloplegic refractions. It is necessary to perform cycloplegia for Chinese young adults with dark irises to obtain accurate refractive errors. We suggest that cycloplegic autorefraction using tropicamide may be considered as a reliable method for epidemiological studies of refraction in Chinese young adults with dark irises.Trial registrationThe study was registered on September 7, 2019 (Registration number: ChiCTR1900025774).

Prevalence and causes of visual impairment among hearing impaired students in Lagos, Nigeria

ObjectivesTo determine the prevalence and causes of visual impairment in hearing-impaired students in Lagos, Nigeria and to assess their level of ophthalmic care utilization. MethodsDescriptive cross sectional study carried out in a primary school for hearing impaired students in Lagos, Nigeria. Socio-demographic characteristics, medical and ocular history were obtained. Ocular examination comprised of distance and near visual acuity assessment; cover tests; anterior segment examination and direct fundoscopy. Visually impaired students had cycloplegic refraction, dilated fundoscopy and subjective refraction. In-depth interviews were carried out for parents of students requiring referral for further eye care. ResultsOne hundred and nine students participated in the study. The prevalence of visual impairment was 19%. The causes of visual impairment were refractive error (11%), amblyopia (6%), cataract (1%) and macular scarring (1%). A lower mean age (p = 0.020) and ocular misalignment (p = 0.037) were associated with visual impairment on multivariate analysis. The spectacle correction coverage was 11% and only 8% of the students had prior ophthalmic care utilization. Ignorance of ocular morbidity and perceived inaccessibility of eye care were cited by parents/guardians as reasons for poor utilization of eye-care services. ConclusionA high prevalence of visual impairment was found among the hearing impaired students; uncorrected refractive error and refractive amblyopia were the most prevalent causes. The level of prior ophthalmic service utilization was found to be low. It was recommended that ophthalmic services especially refractive services should be made available in schools for the hearing impaired.

Agreement of wavefront-based refraction, dry and cycloplegic autorefraction with subjective refraction

PurposeTo evaluate the agreement of dry, and cycloplegic autorefraction and wavefront-based refraction with subjective refraction. Method83 subjects aged 19–57 years were included in this cross-sectional study. Refractive status was determined using four methods including subjective refraction, wavefront-based refraction, dry and cycloplegic autorefraction. Refractive data were recorded as sphere, cylinder and spherical equivalent (SE). Power vector components were used to compare the astigmatism obtained using the different methods of refraction. ResultsThe more negative spherical, cylindrical and SE components were obtained using dry autorefraction, wavefront-based refraction and dry autorefraction, respectively. The less negative spherical, cylindrical and SE components were obtained using cycloplegic autorefraction, subjective refraction and cycloplegic autorefraction, respectively. Considering the spherical component, there was a statistically significant hyperopic shift (0.12 ± 0.29 D, p = 0.001) with cycloplegic autorefraction and a significant myopic shift (−0.17 ± 0.32 D, p < 0.001) with dry autorefraction compared to subjective refraction, while the difference between wavefront-based and subjective refraction was not significant statistically (p = 0.145). The calculated cylindrical component using subjective refraction showed statistically significant difference with dry auto-refraction (p < 0.001), cycloplegic auto-refraction (p = 0.041) and wavefront refraction (p < 0.001). The highest correlation with subjective refraction in sphere, cylinder and SE was observed for cycloplegic auto-refraction (rs = 0.967), dry auto-refraction (rs = 0.983) and cycloplegic auto-refraction (rs = 0.982), respectively. ConclusionsAs subjective refraction is gold standard in our study, sphere in cycloplegic auto-refraction and astigmatism in dry auto-refraction showed better agreement and correlation.

The Difference of Refraction Between the Cycloplegic Retinoscopy and Non-Cycloplegic Subjective Refraction in Children Aged 6 to 15 Years

Objective: To determine the difference of refraction measured by cycloplegic retinoscopy (CR) and non-cycloplegic subjective refraction (NS). Materials and Methods: The present descriptive study included normal children aged 6 to 15 years with refractive error. The refractive status was measured by CR and cycloplegic autorefractometer (CA) at the initial visit. At 2-week follow-up, the refraction was measured with non-cycloplegic autorefractometer (NA) and NS. The spherical equivalent (SE) from participants’ right eye was used in the data analyses. Results: Forty-four participants were included in this study with a mean age of 9±3 years and 22 (50%) were male. Overall, the median (Q₁, Q₃) of SE by CR, CA, NS, and NA were –1.00 (–2.50, 0.25), –1.63 (–2.63, –0.50), –1.63 (–2.50, –1.00), and –1.88 (–2.88, –1.13) diopters (D), respectively. The SE by CR was 0.56 D more than NS (p&lt;0.001), and 0.38 D more than CA (p&lt;0.001). The SE by NS was 0.25 D more than NA (p=0.008). By using the CR method, 11 (25%) participants were classified in the hyperopic group (positive SE) and 33 (75%) in the myopic group (negative SE). In the hyperopic group, the median (Q₁, Q₃) of SE by CR and NS were 0.75 (0.50, 1.75) and –0.63 (–1.00, 1.38) D, respectively. The refraction by CR was 1.50 D more than by NS (p=0.003). In the myopic group, the median (Q₁, Q₃) of SE by CR and NS were –1.50 (–2.50, –0.75) and –2.00 (–3.25, –1.50) D, respectively. The refraction by CR was 0.50 D more than NS (p&lt;0.001). Conclusion: The refraction in children aged 6 to 15 years measured by CR was significantly more than NS in the participants. The authors should decrease the number of refractions obtained from CR when prescribing glasses to hyperopic children. Keywords: Refractive error, Children, Cycloplegic retinoscopy, Subjective refraction, Cycloplegic autorefractor, Manifest autorefractor

Comparison of endpoint of subjective cycloplegic refraction with artificial aperture and post-mydriatic test among adults with refractive error.

PURPOSE:There is a need to understand the requirement for the post-mydriatic test (PMT) among adults for the final prescription of spectacles as this test increases the cost of eye care and causes inconvenience to the patient because of the additional visit to an eye care practitioner. We aim to compare the cycloplegic subjective refraction using apertures of various sizes and PMT in an adult population.METHODS:This prospective crossover study was conducted under standard settings in an eye clinic. Adult individuals between 18 and 35 years of with emmetropia and various degrees of ametropia participated in this study. Individuals with known ocular pathology were excluded. Non-cycloplegic objective refraction was performed followed by subjective refraction. Cycloplegic objective refraction was performed followed by subjective refraction with custom designed artificial apertures. After a washout period of cycloplegic, PMT was performed. The distribution of data was tested using the Kolmogorov–Smirnov test. Depending on the distribution of the data, either parametric or nonparametric test was done.RESULTS:Fifty-nine eyes of thirty individuals with a mean (±SD) age of 23(±4) years with a male: female ratio of 1:4 participated in this study. A comparison of measures of PMT and subjective refraction with 2, 3, 4, 5, and 6 mm aperture under cycloplegic effect using the Friedman test rendered a Chi square value (df = 5) of 1.92 which was not statistically different (P = 0.86).CONCLUSION:Performing subjective refraction with an appropriate spherical and cylindrical endpoint under cycloplegic effect with appropriate aperture overcomes the necessity of PMT.

Self-adjustable Spectacle Wearing Compliance and Associated Factors among Rural School Children in Ghana.

Self-adjustable spectacles are increasingly being used in refractive service delivery programs in developing countries. Despite the success of self-refraction as a refraction technique, compliance with actual wear of adjustable spectacles has not been evaluated. Findings in this study have significant programmatic implications for the effectiveness and sustainability of this mode of correction in developing countries. The purpose of this study was to assess compliance with wearing of adjustable spectacles and factors associated with compliance in pre-teen schoolchildren at 6 months after spectacles were dispensed. A cohort of 86 children aged 6 to 12 years with presenting vision worse than or equal to 6/12 in the better eye that could be improved to better than or equal to 6/7.5 by subjective refraction and who were identified from a randomized sample of 18 primary schools in the coastal areas of Cape Coast in Ghana received free FocusSpecs adjustable spectacles after successfully completing self-refraction and cycloplegic subjective refraction. Follow-up examination to assess compliance and to determine reasons for noncompliance was conducted at 6 months after spectacle provision. Logistic regression models assessed factors associated with spectacle wear compliance (95% confidence intervals [CIs]). Spectacle wear compliance was 33.7% (95% CI, 31.3 to 36.1%); an additional 29% had their spectacles with them but were not wearing them. The major reasons given by the children for noncompliance were "loss" (32%; 18/57) and "breakage" (23%; 13/57). Modest compliance (49%) was observed among the poorer children who attend public schools. Attending public school was the only predictor of compliance to spectacle wear (odds ratio, 3.096; 95% CI, 1.228 to 7.805; P = .02). Despite accurate self-refraction by most children, only a small proportion was compliant with actual wear of the spectacles. Loss and breakage were the major reasons for noncompliance. The poorer children who attend public schools, who stand to benefit most from the technology, were the ones more likely to be compliant with wear.

Role of corneal biomechanical properties in predicting of speed of myopic progression in children wearing orthokeratology lenses or single-vision spectacles

ObjectiveTo determine the characteristics of children who were likely to progress rapidly and gain the greatest benefit from orthokeratology (ortho-k) treatment.Methods and analysisThe files of 113 children who participated in...

Refractive Errors Progression in Brazilian Low-Income School Children

Purpose: To assess the progression of refractive error (RE) in low-income school children in Sao Paulo, Brazil. Methods: The study population consisted of a cohort of children (11-14 years of age) from 9 randomly chosen public schools from a study performed in 2004-2005, with refraction in those with visual impairment (uncorrected distance visual acuity ≤ 20/40 in either eye). Eligible participants were those identified in the baseline study as visually impaired. Three years later, follow-up recruitment consisted of invitation for a free ophthalmic exam in the school facilities. Cycloplegic auto-refraction, cycloplegic subjective refraction and fundus examination were performed in those refracted at baseline and follow-up. Risk factors for refractive errors were investigated by administering questionnaires on family demographics, parental glasses usage and near work/outdoor activities. Results: A cohort of 218 children was eligible for a 3-year follow-up, with 136 examined. Myopic progression of -0.50 to -1.49 spherical equivalent (SE) was found in both eyes of 64 (47.1%) children, in 22 (16.2%) firstly right eyes tested only and in 15 (11.0%) second eyes tested only. Both eyes of 14 (10.3%) children had progressed < -1.50 SE, with 11 (8.1%) progressing only in their second eyes tested and 6 (4.4%) in their first eye tested. In multiple regression analysis myopic progression was associated with both parents wearing glasses (p<0.05). Conclusions: Very mild refractive error progression was detected in a low-income urban Brazilian school children population, confirming the previous finding of low prevalence of refractive errors leading to visual impairment in this population.

Comparison of objective refraction in darkness to cycloplegic refraction: a pilot study

BackgroundThe aim was to assess non‐cycloplegic objective refraction in darkness using an open‐field auto‐refractor, and furthermore to compare it with distance cycloplegic subjective refraction and distance cycloplegic retinoscopy in the light, in children and young adults.MethodsTwenty‐three, visually‐normal, young‐adults (46 eyes) ages 23 to 31 years, and five children (10 eyes) ages five to 12 years, participated in the study. The spherical component of their refraction ranged from −2.25 D to +3.75 D with a mean of +1.80 D, and a mean cylinder of −0.70 D. Three techniques were used to assess refractive error. An objective measure of the non‐cycloplegic refractive state was obtained using an open‐field autorefractor (WAM‐5500) after five minutes in the dark to allow for dissipation of accommodative transients and relaxation of accommodation. In addition, both distance retinoscopy and subjective distance refraction were performed following cycloplegia (Cyclopentolate, 1%) using conventional clinical procedures. All measurements were obtained on the same day within a single session. The spherical component of the refraction was compared among the three techniques in both the children and adults.ResultsThere was no significant difference in spherical refraction among the three techniques: non‐cycloplegic objective refraction in the dark, distance cycloplegic retinoscopy and distance cycloplegic subjective refraction, in either the adults [F(2, 137) = 0.79, p = 0.45] or the children [F(2, 27) = 0.47, p = 0.62]. Mean difference in the spherical component between refraction in the dark and the cycloplegic distance retinoscopy was −0.34 D (r = 0.89) in the adults and +0.14 D (r = 0.96) in the children. The mean difference in spherical component between refraction in the dark and the cycloplegic distance subjective refraction was −0.25 D (r = 0.92) in the adults and −0.05 D (r = 0.95) in the children.ConclusionComparison of the spherical refractive component between the three techniques was not significantly different and furthermore, they were highly correlated in both the children and adults in this pilot study. Non‐cycloplegic refraction in the dark may provide a reliable adjunct or alternative to conventional cycloplegic refraction in both children and young adults.

Self-refraction accuracy with adjustable spectacles among children in Ghana.

To determine the accuracy of self-refraction (SR) in myopic teenagers, we compared visual and refractive outcomes of self-refracting spectacles (FocusSpecs) with those obtained using cycloplegic subjective refraction (CSR) as a gold standard. A total of 203 eligible schoolchildren (mean [±SD] age, 13.8 [±1.0] years; 59.1% were female) completed an examination consisting of SR with FocusSpecs adjustable spectacles, visual acuity with the logMAR (logarithm of the minimum angle of resolution) chart, cycloplegic retinoscopy, and CSR. Examiners were masked to the SR findings. Wilcoxon signed rank test and paired Student t test were used to compare measures across refraction methods (95% confidence intervals [CIs]). The mean (±SD) spherical equivalent refractive error measured by CSR and SR was -1.22 (±0.49) diopters (D) and -1.66 (±0.73) D, respectively, a statistically significant difference of -0.44 D (p < 0.001, t = 15.517). The greatest proportion of participants was correctable to visual acuity greater than or equal to 6/7.5 (logMAR 0.1) in the better eye by CSR (99.0%; 95% CI, 96.5 to 99.7%), followed by cycloplegic retinoscopy (94.1%; 95% CI, 90.0 to 96.6%) and SR (85.2%; 95% CI, 79.7 to 89.5%). These proportions differed significantly from each other (p < 0.001, Wilcoxon signed rank test). Myopic inaccuracy of greater than 0.50 D and greater than or equal to -1.00 D was present in 29 (15.3%) and 16 (8.4%) right eyes, respectively, with SR. In logistic regression models, failure to achieve visual acuity greater than or equal to 6/7.5 in right eyes with SR was significantly associated with age (odds ratio, 1.92; 95% CI, 1.12 to 3.28; p = 0.017) and spherical power (odds ratio, 0.017; 95% CI, 0.005 to 0.056; p < 0.001). Self-refraction offers acceptable visual and refractive results for young people in a rural setting in Ghana, although myopic inaccuracy in the more negative direction occurred in some children.

Prevalence of visual impairment and refractive errors among different ethnic groups in schoolchildren in Turpan, China.

There is currently limited information about ethnic differences in myopia prevalence within mainland China, especially in rural or semi-rural areas. We examined the prevalence of refractive errors, visual impairment and spectacle coverage in school children of varying ethnicity in Turpan, Xinjiang province. A community eye care service was provided for five schools. Presenting monocular distance and near visual acuity (VA), and ocular alignment were assessed. Retinoscopy and cycloplegic subjective refraction were performed for participants with presenting visual impairment (distance VA worse than 0.3 logMAR; Snellen 6/12 or 20/40) or abnormal binocular vision. Questionnaires administered prior to the eye examinations were used to collect information regarding personal lifestyle and parental myopia. A total of 646 out of 690 (94%) subjects aged four to 19 years (11.9 ± 2.6; mean ± S.D.) completed the eye examination. Three hundred and eighty-two (59%) of participants were of Uyghur ethnicity, followed by Han, 176 (27%) and Hui, 74 (12%). The mean age of Uyghur, Han and Hui students was 12.3 ± 2.7, 11.4 ± 2.6 and 11.4 ± 2.3 years respectively, in which the Uyghur students were significantly older than the Han and Hui students (F(3,631) = 5.58 p < 0.001). In total, 170 (27%) and 85 (13%) subjects failed the screening examination for one eye or both eyes, respectively. The prevalence of presenting visual impairment was not significantly different among the ethnic groups (p = 0.26). After cycloplegic refraction, most subjects' VA (98%) improved to better than 0.3 logMAR (Snellen 6/12 or 20/40). The prevalence of "clinically-significant myopia" (≤-0.50 dioptres) was 27%, 18% and 13% in Han, Hui and Uyghur children, respectively (p < 0.001). In contrast, Uyghur students had the highest prevalence of astigmatism (Uyghur 12%, Han 5%, Hui 4%). The overall spectacle coverage was 36%, while spectacle coverage among ethnic groups were similar (Han, 41%; Uyghur, 32%; Hui, 41%; χ(2) = 2.23, df = 2, p = 0.33). The prevalence of clinically significant myopia varied markedly with ethnicity in school children sampled from a semi-rural region of mainland China (Han > Hui > Uyghur). As reported previously, uncorrected/under-corrected refractive error was the main cause of presenting visual impairment.

Central and peripheral autorefraction repeatability in normal eyes.

To determine the between-visit repeatability of peripheral autorefraction measurements using the Grand Seiko WAM-5500 in normal eyes. Cycloplegic autorefraction of the right eye was measured on 25 myopic young adults using a modified Grand Seiko autorefractor. Measurements were made centrally (along the line of sight) and ±20, ±30, and ±40 degrees from the line of sight in the horizontal meridian at two visits separated by 1 to 15 days. Five autorefraction measurements at each location were converted to vector space and averaged. Relative peripheral refraction (RPR) was calculated as the difference between the peripheral and central spherical equivalent. Between-visit repeatability was evaluated by plotting the difference versus the mean of the measurements at the two visits (bias) and by calculating the 95% limits of agreement (LoA). The mean (±SD) age and spherical-equivalent refractive error centrally (at visit 1) were 24.0 ± 1.3 years and -3.45 ± 1.42 diopters (D), respectively. There was no significant between-visit bias for any refractive component evaluated (M, J0, J45, and RPR) at any location measured (all p > 0.05). The 95% LoA of defocus (M) was ±0.21 D centrally and increased with increasing eccentricity to ±0.73 and ±0.88 D at 40 degrees nasally and temporally on the retina, respectively. The 95% LoA of RPR increased with increasing eccentricity to ±0.67 and ±0.82 D at 40 degrees nasally and temporally on the retina, respectively. In normal eyes, the repeatability of cycloplegic autorefraction was best centrally and decreased as eccentricity increased; however, repeatability in the far periphery was still better than previously reported between-visit repeatability for foveal cycloplegic subjective refraction. With clear knowledge of the repeatability of on- and off-axis cycloplegic autorefraction with the Grand Seiko, peripheral measurements can be properly interpreted in longitudinal studies.