Non-cycloplegic screening for refractive errors in children with the hand-held autorefractor Retinomax: final results and comparison with non-cycloplegic photoscreening

Photoscreening for amblyopia risk factors assessment in young children: A systematic review with meta-analysis

PURPOSE

Amblyopia is a leading cause of preventable and treatable vision loss in the pediatric population. Instrument-based screening of amblyopia-risk factors is being widely adopted but the audit of its results is still lacking. We sought to review the existing evidence regarding the outcomes of photoscreening applied to children under the age of three years.

METHODS

A three-database search (Pubmed, ISI Web of Science, and Scopus) was performed from inception to March 2021. A meta-analysis of proportions was conducted to summarize the referral rate, untestable rate and positive predictive value (PPV).

RESULTS

Thirteen studies were selected among 705 original abstracts. The quantitative analysis included twelve studies enrolling 64,041 children. Of these, 13% (95%CI: 7-19%) were referred for further confirmation of the screening result. Astigmatism was the most common diagnosis both after screening and after ophthalmologic assessment of referred children. The pooled untestable rate and PPV were 8% (95%CI: 3-15%) and 56% (95%CI: 40-71%), respectively.

CONCLUSION

There is no global consensus on the optimal age, frequency or what magnitude of refractive error must be considered an amblyopia-risk factor. Optimization of referral criteria is therefore warranted.

Comparison of Interpupillary Distance, Pupillary Diameter and Corneal Reflex Measured with Plusoptix A09 in Normally Developing Children and Autism

Aim: Autism Spectrum Disorder (ASD) is a developmental disorder that can present with an abnormality of the autonomic nervous system (ANS symptoms).Method: In this study, 38 eyes of 19 ASD were included with 19 healthy children (control group). Participants were analyzed according to their characteristics. Here, used the Plusoptix A09 devices to measure the difference in pupil size, corneal reflex, and interpupillary distance (IPD) between ASD and healthy children.Results: The mean age±standard deviation (SD) for the autism group was 4,6±2,5 years (range 2-11 years). In the group of normally developing children, the mean age was±SD 5,02±2,6 years (range 2-11 years). The size of the right pupil (p=0,006) and left pupil (p=0,007) was found to be significantly different in the control and experimental groups. IPD (p=0,000) was statistically significant between groups unlike the corneal reflex was not (p=0,173). The p-value is less than 0,05 in all statistical results.Conclusion: As a result, pupil diameter and IPD of children with autism were found to be larger than the control group, but there was no significant difference in corneal reflex. Pupillary measurements reveal differences between people with ASD.  

The Impact of Early Photoscreening on Medium-term Visual Acuity: A Population-Based Study

PURPOSE

To analyze the outcomes of an early ophthalmological intervention in children included in the pilot project of the "Rastreio de Saúde Visual Infantil" (RSVI) visual screening program in Portugal.

METHODS

This was a retrospective analysis of the medical records of all children included in the RSVI from April 1, 2016 to December 31, 2016, and who were referred to an ophthalmology appointment. Data of refractive errors, anisometropia, amblyopia, instituted treatments, and visual acuity at the end of the ophthalmological intervention were collected.

RESULTS

Two hundred sixty-seven (18.2%) 2-year-old children from the Centro Hospitalar Universitário do Porto reference area had a positive screening result and were subsequently referred to an ophthalmology appointment. Glasses were prescribed to 31.1% of the patients who attended. Presumed amblyopia was diagnosed in 2.5% and occlusion was prescribed. At the end of a median follow-up of 3 years, of those who wore glasses without occlusion, 94.3% had a visual acuity of 20/25 or better in both eyes with an asymmetry of two lines or less between eyes. Of the 4 children who wore glasses with occlusion, 3 of them had a visual acuity of 20/25 or better in both eyes with an asymmetry of two lines or less between eyes.

CONCLUSIONS

This study demonstrates the effectiveness of an early intervention in the prevention and treatment of amblyopia, because after a median follow-up of 3 years after treatment none of the referred children met criteria for amblyopia and 94.3% of the referred children who had an intervention had a normal visual acuity. [J Pediatr Ophthalmol Strabismus. 20XX;X(X):XX-XX.].

Light Intensity in Nursery Schools: A Possible Factor in Refractive Development

PURPOSE

Increased levels of outdoor light have been found to be associated causally with decreased rates of myopia. The goal of this study was to measure the effect of indoor nursery school light intensity on refraction of preschool children in Israel.

METHODS

A total of 1596 children aged 4 to 5 years from 27 nursery schools were examined. Light intensity was tested with a luxmeter device (Lux) inside and outside the nursery school. Noncycloplegic refractions were measured with the PlusOptix vision A09 screening device. Data analysis was performed using Pearson coefficients, chi-square tests for proportions and ANOVA tests by tertiles of illuminance.

RESULTS

This study included 1131 kindergarten children with a mean age of 4.87 ± 0.33 years, of which 571 were female (50.5%). The mean light intensity of the low, medium, and high intensity groups differed significantly (ANOVA P < 0.001) at 359 ± 2.64 lux (range 264-431), 490 ± 2.21 lux (range 432-574), and 670.76 ± 3.73 lux (range 578-804), respectively. Mean spherical equivalent (SE) was +0.56 ± 0.03D for the low-intensity group, +0.73 ± 0.03D for the medium-intensity group, and +0.89 ± 0.03D for the high-intensity group (ANOVA P < 0.001). The low-intensity group had 42.1% of children with zero refraction or less, while the high-intensity group had 19.3%.

CONCLUSIONS

In the nursery schools, lower amounts of illumination were associated with less hyperopic refractive error. As the low hyperopic reserve is a risk factor for developing myopia, this finding needs to be followed up to establish whether this association reflects a causal relationship, which could be modulated for the prevention of myopia.

Ellipsoid Spectacle Comparison of Plusoptix, Retinomax and 2WIN Autorefractors

BACKGROUND

Handheld devices can automatically give an estimate of refraction. The established method for refraction comparison using spherical equivalent (M) and J0, J45 vector transformations by Bland-Altman analysis is too complex for non-eye doctors involved with vision screening and remote vision clinics. Therefore, a simpler comparison technique was developed.

METHODS

Based on the spectacle limit to resolve grade A 1 logMAR, B 3 logMAR and C 6 logMAR blur, J0, J45, and M are combined into the Alaska Blind Child Discovery (ABCD) composite ellipsoid GRADE system. Pediatric eye patients had confirmatory examination after dry refraction with three portable autorefractors: Plusoptix, 2WIN and Retinomax. The refractions were then compared using both Bland-Altman and ABCD composite. Performance to detect AAPOS amblyopia risk factors was also assessed.

RESULTS

A total of 202 children, mean age seven years, 28% high spectacle need and 43% AAPOS 2013 amblyopia risk factors showed high correlation with cycloplegic refraction (intraclass correlation 0.49 to 0.90) for sphere, J0 and J45 spectacle components. Plusoptix had more (10%) inconclusives due to patients out-of-range. The Retinomax was unable to screen some younger children and was less reliable for sphere but gave more precise astigmatism estimates. The proportion of autorefractions expected to give GRADE A/B high-need patients acuity improvement to 20/40 would be 41% for Plusoptix, 39% for 2WIN and 65% for Retinomax. Sensitivity/specificity for amblyopia risk factor detection was 80%/83% for Plusoptix, 72%/88% for 2WIN and 84%/73% for Retinomax.

CONCLUSION

The simplified spectacle comparison resembled Bland-Altman and could assist lay vision screeners and non-eye doctors attempting remote spectacle donation worldwide.

Costs and effectiveness of two models of school-entry visual acuity screening in the UK

Cost effectiveness of different visual screening modalities cannot be calculated without long-term outcome data. This paper reports detailed outcomes from a gold-standard UK recommended orthoptist-delivered screening (ODS) at 4-5 years in school, compared to a neighboring school-nurse delivered screening (SNDS), both feeding into the same treatment pathway. The target condition was reduced visual acuity (VA) of worse than logMAR 0.2 in either eye.Available records from screening databases and hospital records were analyzed, comparing the two services wherever possible.More screening data was available from the ODS. ODS: 5706 screened, 3.5% referred. False positives 6.5%, PPV 91.4%, sensitivity 97.9%, and specificity 99.8% for reduced VA. Cost per child with reduced vision detected £195.22, and per amblyope detected £683.28. The mean treatment cost per child with reduced VA was £331.68 and for amblyopia treatment was £458.65.SNDS: 5630 screened and 3.8% referred (plus some referrals to local optometrists lost to follow up). False positives 34%, PPV 53.2%, sensitivity and specificity estimated as 89.3% and 98.67%. Costs to secondary services of false positives were seven times greater. The cost per child with confirmed reduced vision seen at the hospital was 46% more; and per amblyope detected was 39% more.Outcomes for treatment post referral in both groups were similar and excellent. 86% of genuine referrals improved to within normal limits with glasses alone. Of 221 genuine referrals with final outcome data, all now have better than 0.2logMAR acuity in the better eye and only two (0.9%) have residual amblyopia in one eye worse than 0.4logMAR.About 14-18% of children with reduced VA would have passed AAPOS photoscreening referral criteria.An orthoptist-delivered single VA screen at 4-5 years is highly cost effective with good outcomes. The main contributing factors to success appear to be training and experience in accurate VA testing, the opportunity to rescreen equivocal results, and monitoring, audit, and feedback of outcomes.

Comparison of keratometry data using handheld and table-mounted instruments in healthy adults

PURPOSE

To compare keratometry data between the handheld Retinomax K-plus 3 and the table-mounted IOLMaster 700.

METHODS

Healthy adult volunteers were prospectively recruited to the study. All participants underwent 3 consecutive keratometry measurements using the Retinomax K-plus 3 and a single biometry assessment using the IOLMaster 700. Differences between the Retinomax K-plus 3 and the IOLMaster 700 were assessed using Wilcoxon test for paired samples, Spearman correlation, Bland-Altman and mountain plots.

RESULT

Twenty-eight healthy subjects with a median age of 37 years (interquartile range (IQR) 28-44 years) were included in the study. The median mean keratometry (mean K) reading was higher using the Retinomax K-plus 3 (44.04D; IQR 42.96-45.61D) compared to the IOLMaster 700 (43.78D; IQR 43.22-44.90D, p < 0.01), with a mean difference of 0.18D (95% confidence interval (CI) 0.11-0.23D). Mean K readings were highly correlated between the 2 devices (r = 0.995, p < 0.01). Bland-Altman plots showed 95% limits of agreement between -0.14D and 0.49D. Frequency histogram of mean K reading differences between the Retinomax K-plus 3 and the IOLMaster 700 showed that 56% of cases were between ± 0.2D, 93% of cases were between ± 0.4D and all cases were between ± 0.5D. Mean corneal astigmatism measurement was higher using the Retinomax K-plus 3 (1.01 ± 0.40D) compared to the IOLMaster 700 (0.77 ± 0.36D), with a mean difference of 0.23 ± 0.37D (p < 0.01) between the devices.

CONCLUSIONS

A good agreement exists between the Retinomax K-plus 3 and the IOLMaster 700 regarding keratometry readings. This enables cataract surgeons to safely use the Retinomax K-plus 3 device when indicated.

Comparison between Plusoptix A09 and gold standard cycloplegic refraction in preschool children and agreement to detect refractive amblyogenic risk factors

BACKGROUND:

The preschool children hardly complain about their vision problems. It is of paramount importance to screen them with an objective tool and compare with the gold standard technique.

AIM:

To compare the values obtained with Plusoptix A09 and cycloplegic refraction in 3–6 years children and agreement to detect refractive amblyogenic risk factors.

SUBJECTS AND METHODS:

A cross-sectional study was conducted in the Outpatient Department of Ophthalmology in a tertiary care hospital. Informed consent from parents and verbal assent from children were obtained. Each subject had monocular vision assessment with Lea symbol chart, stereo acuity measurement with Frisby, refractive screening with Plusoptix A09, squint assessment, and anterior segment evaluation before administering Homatropine hydrobromide (homide) 2% eye drops. Cycloplegic refraction and posterior segment evaluation were performed for final diagnosis.

STATISTICAL ANALYSIS:

Descriptive statistics were used to summarize the data. Spearman correlation coefficient and kappa statistics were also employed.

RESULTS:

In total, data of 94 children were analyzed. The correlation values obtained between plusoptix and cyclorefraction values for spherical, cylindrical, spherical equivalent were 0.508 (P < 0.0001), 0.779 (P < 0.0001), and 0.407 (P < 0.0001), respectively. Refractive errors were seen in 32% and amblyopia in 17% of eyes. Kappa value was κ = 0.974 in detecting refractive amblyogenic risk factors.

CONCLUSION:

Good correlation was found between the plusoptix and cyclorefraction values. Cylindrical values showed a better correlation. Refractive errors and amblyopia were the major ocular disorders observed. There was significant agreement between the refractive techniques in detecting amblyogenic risk factors.

Scope and costs of autorefraction and photoscreening for childhood amblyopia-a systematic narrative review in relation to the EUSCREEN project data

Background

Amblyopia screening can target reduced visual acuity (VA), its refractive risk factors, or both. VA testing is imprecise under 4 years of age, so automated risk-factor photoscreening appears an attractive option. This review considers photoscreening used in community services, focusing on costs, cost-effectiveness and scope of use, compared with EUSCREEN project Country Reports describing how photo- and automated screening is used internationally.

Methods

A systematic narrative review was carried out of all English language photoscreening literature to September 10th 2018, using publicly available search terms. Where costs were considered, a CASP economic evaluation checklist was used to assess data quality.

Results

Of 370 abstracts reviewed, 55 reported large-scale community photoscreening projects. Five addressed cost-effectiveness specifically, without original data. Photoscreening was a stand-alone, single, test event in 71% of projects. In contrast, 25 of 45 EUSCREEN Country Reports showed that if adopted, photoscreening often supplements other tests in established programmes and is rarely used as a stand-alone test. Reported costs varied widely and evidence of cost-effectiveness was sparse in the literature, or in international practice. Only eight (13%) papers compared the diagnostic accuracy or cost-effectiveness of photoscreening and VA testing, and when they did, cost-effectiveness of photoscreening compared unfavourably.

Discussion

Evidence that photoscreening reduces amblyopia or strabismus prevalence or improves overall outcomes is weak, as is evidence of cost-effectiveness, compared to later VA screening. Currently, the most cost-effective option seems to be a later, expert VA screening with the opportunity for a re-test before referral.

Accuracy of the Hand-held Wavefront Aberrometer in Measurement of Refractive Error

Purpose

To compare refractive error measured by hand-held wavefront aberrometers with postcycloplegic autorefraction (AR) and cycloplegic refraction (CR).

Methods

The medical records of patients who received refractive measurements using the wavefront aberrometer, postcycloplegic AR, and CR between January 2014 and January 2016 were retrospectively analyzed. The mean differences, 95% confidence intervals, and limits of agreement (LOA) were calculated for the refractive vector components (M, J₀, and J₄₅).

Results

Fifty-one patients (9.0 ± 5.5 years, male 41.2%) were enrolled in this study, and only the right eye of each was included. Refractive errors ranged from −9.25 to +7.25 diopters (D) for spherical equivalent (median, 0.75 D). The M component was not significantly different among the three methods (p = 0.080). However, the J₀ vector component was significantly different (p < 0.001). After post hoc analysis, the wavefront aberrometer obtained more positive values for J₀ compared to the other methods. The J₄₅ component was not significantly different among the three methods (p = 0.143). The mean difference between the wavefront aberrometer and postcycloplegic AR was −0.115 D (LOA, −1.578 to 1.348 D) for M, 0.239 D (LOA, −0.371 to 0.850 D) for J₀, and −0.015 D (LOA, −0.768 to 0.738 D) for J₄₅. The mean difference between the wavefront aberrometer and CR was −0.220 D (LOA, −1.790 to 1.350 D) for M, 0.300 D (LOA, −0.526 to 1.127 D) for J₀, and −0.079 D (−0.662 to 0.504 D) for J₄₅.

Conclusions

The wavefront aberrometer showed good agreement with postcycloplegic AR and CR in spherical equivalents, but tended to produce slightly myopic results. The wavefront aberrometer also overestimated with-the-rule astigmatism. Therefore, we recommend that the device be used for estimations of refractive error, which may be useful for patients who have postural difficulties, live in undeveloped countries, or are bedridden.

Are the results of handheld auto-refractometer as valid as the result of table-mounted refractometer?

Purpose

To determine the agreement of table-mounted and handheld auto-refractometers and to evaluate the effect of age and different types of refractive errors on this comparison.

Methods

In this cross-sectional study conducted in 2015 using multi-stage cluster sampling, two underserved villages were selected randomly in the north and southwest of Iran. All the selected participants underwent optometric and ophthalmic examinations. Refraction was measured using handheld and table-mounted auto-refractometers in 652 subjects.

Results

The mean age of the subjects was 32.7 ± 18.72 years, and 58.3% of them were female. A significant difference was observed in the results of sphere, spherical equivalent (SE), and J45 vector between the two devices (P < 0.012), but there was no significant difference in J0 vector. There was a significant difference in the results of sphere between the two devices in all age groups under 50 years (P = 0.005), but there was no difference in age groups above 50 years. Correlation coefficients of the two devices were 0.989, 0.986, 0.908, and 0.951 for the results of sphere, SE, J0 vector, and J45 vector, respectively (P < 0.0001). The 95% limit of agreement (LOA) of the two devices was -0.31 to +0.53 for sphere, -0.27 to +0.63 for SE, -0.27 to +0.27 for J0 vector, and -0.16 to -0.17 for J45 vector.

Conclusions

According to our findings, the spherical error and cylindrical power measurements of the two devices have a significant correlation. Although there is a significant difference in the mean values between the two devices, this difference may be considered clinically insignificant, and considering the narrow 95% LOA between the two devices, the results may be used interchangeably.

Accuracy of PlusOptix A09 distance refraction in pediatric myopia and hyperopia

Background

The PlusOptix photoscreeners (PlusOptix GmbH, Nuremberg, Germany) is used in many vision screening programs. The purpose of the present study was to further explore the accuracy of the PlusOptix A09 photoscreener in children with ametropia (myopia or hyperopia).

Methods

A total of 70 eyes (35 children) were prospectively included. Before administration with the cycloplegia treatment 1 % cyclopentolate hydrochloride, children underwent refraction measurement with the PlusOptix A09. A refraction was then performed after cycloplegia with either Retinomax hand-held or Nidek autorefractor before and after 3 years old, respectively.

Results

The median (interquartile range) age was 58 (18 to 86) months. The mean (SD) spherical equivalent differed between PlusOptix A09 and cycloplegic autorefraction (+0.54 [1.82] D vs +1.06 [2.04] D, p = 0.04). PlusOptix A09 refraction was positively correlated with cycloplegic autorefraction (r = 0.81, p < 0.001) with higher coefficient in myopic than in hyperopic children (r = 0.91, p = 0.0002 and r = 0.52, p = 0.01, respectively). The mean (SD) difference between PlusOptix A09 and cycloplegic autorefraction was higher with hyperopia than myopia (0.73 [1.34] vs 0.05 [0.66], p = 0.01). The proportion of children with < 1-D difference between cycloplegic and PlusOptix A09 refraction was 68.8 %, higher with myopia than hyperopia (90 % vs 54.5 %, p = 0.01).

Conclusion

The spherical equivalent value with non-cycloplegic PlusOptix A09 refraction is closer to that with cycloplegic autorefraction than non-cycloplegic autorefraction. The PlusOptix A09 photoscreener underestimated the hyperopia of 0.73 D and slightly overestimated myopia of 0.05 D. The PlusOptix A09 could be used for screening with higher accuracy in myopic than hyperopic children.

A Comparison of Refraction Defects in Childhood Measured Using Plusoptix S09, 2WIN Photorefractometer, Benchtop Autorefractometer, and Cycloplegic Retinoscopy

PURPOSE

To compare Plusoptix (Gmbh, Nuremberg, Germany), 2WIN (Adaptica, Padua, Italy), the benchtop refractometer (Auto-Kerato-Refractometer KR-8900; Topcon Co, Tokyo, Japan), and retinoscopy with regard to the consistencies.

MATERIALS AND METHODS

In our prospective study, 200 eyes of 100 patients were included. We analyzed the demographics and characteristics of the patients, the percentage of patients from whom measurements could not be obtained, the measurements from both patients' eyes of pupil diameter, spherical, cylindrical, axis, and spherical equivalence.

RESULTS

The mean age ± SD was 7.8±4.5 years (range, 1-18 years). Pupil diameter measurements were found to be consistent (Cronbach's alpha value >0.8). The sphere and spherical equivalence measurements for both eyes were found to be consistent with each other in all apparatus (Cronbach's alpha value >0.8). However, consistency was found to be lower in cylindrical values and the Jackson cross-cylinder measurements at 0° and 45° axis were found to be inconsistent with each other (Cronbach's alpha value <0.8).

CONCLUSIONS

While consistency was observed in all methods in terms of sphere and spherical equivalence, consistency dropped in cylindrical values and no consistency was observed in axis values. It is important to take this point into consideration, especially in axis measurements.

Performance of the Plusoptix A09 photoscreener in detecting amblyopia risk factors in Chinese children attending an eye clinic

Purpose

To assess the accuracy of the Plusoptix A09 photoscreener in detecting amblyopia risk factors in children and determine referral criteria when using Plusoptix A09 for a large-scale vision screening.

Methods

Pediatric patients attending our eye clinic underwent a comprehensive ophthalmic examination that included photorefraction, orthoptic examination, anterior segment assessment, fundus examination and cycloplegic retinoscopy. The measurements were collected for statistical analyses.

Results

One hundred and seventy-eight children (mean age ± SD: 6.2±2.4 years, range: 2.2 to 14.1 years) were included in the study. The mean spherical equivalent (SE) obtained using Plusoptix A09 (P_SE) was 0.57 D lower than that obtained from cycloplegic retinoscopy (CR_SE) (P = 0.00). However, there was no statistically significant difference of Jackson cross cylinder J₀ and J₄₅ between Plusoptix A09 (P_J) and cycloplegic retinoscopy (CR_J) (P = 0.14, P = 0.26). The relationship of SE obtained from Plusoptix A09 and SE obtained from cycloplegic retinoscopy was presented as the equation: CR_SE = 0.358 + 0.776 P_SE + 0.064 P_SE² + 0.011 P_SE³. Based on the Receiver Operating Characteristic (ROC) curve, the Plusoptix A09 had an overall sensitivity of 94.9% and specificity of 67.5% for detecting refractive amblyopia risk factors. The sensitivity and specificity of the Plusoptix A09 for detection of strabismus were 40.7% and 98.3%, respectively; detection of amblyopia and/or strabismus was 84.7% and 63.2%, respectively.

Conclusions

The Plusoptix A09 photoscreener underestimated hyperopia and overestimated myopia according to SE when compared with cycloplegic retinoscopy. The accuracy of the Plusoptix A09 in detecting amblyopia risk factors in children could be improved by the regression equation and optimized criteria for refractive amblyopia risk factors developed in the present study. Moreover, the Plusoptix A09 photoscreener is not suitable for a large-scale strabismus screening when it is applied solely.

Efficient referral thresholds in autorefraction-based preschool screening

PURPOSE

To determine economically efficient referral criteria for a preschool vision-screening program using autorefraction.

DESIGN

Retrospective economic evaluation of a screening protocol.

METHODS

Preschoolers in 2 cities received preschool-based Retinomax screening with a standard referral protocol and as-needed comprehensive eye examinations in 2012-2013. Positive predictive values and referral criteria that minimized cost per case detected were derived using data from San Francisco. These modeled referral criteria were then retrospectively tested for cost-effectiveness against other common criteria in Oakland with sensitivity analysis. Cases were defined by American Association for Pediatric Ophthalmology and Strabismus (AAPOS) criteria for amblyopia risk factors. The perspective was a third-party payer. Costs were obtained from a regional insurance provider.

RESULTS

In San Francisco, 3974 children were screened, 631 referred, and 412 examined. Forty-eight percent of referrals, 301 children, met more than 1 of the referral criteria. Positive predictive values ranged from 7% for myopia to 56% for astigmatism. In Oakland, 2359 children were screened and 269 were examined. When applying the modeled referral criteria derived from San Francisco to the population of Oakland, the cost per case detected was $258. When compared in Oakland, the original referral criteria and criteria based on Vision in Preschoolers study cost, respectively, $424 and $371 per additional case detected. The modeled referral criteria had a lower cost per case detected across sensitivity analysis.

CONCLUSIONS

More stringent referral criteria may reduce the cost per case detected in vision screening and allow more at-risk children to be detected with the same financial resources.

Comparison of the refractive measurements with hand-held autorefractometer, table-mounted autorefractometer and cycloplegic retinoscopy in children

Purpose

To evaluate the performance of the hand-held and table-top autorefractokeratometer in measuring refractive errors by comparing them with cycloplegic retinoscopy.

Methods

Included in the study were 112 eyes of 112 pediatric patients whose mean age was 6.78 ± 2.61 years (range, 2 to 12 years). The refractive errors of all the eyes were measured with and without cycloplegia using a hand held autorefractokeratometer (Retinomax K-plus 3), table top autorefractokeratometer (Canon RK-F1) and performing cycloplegic retinoscopy. The spherical equivalent, cylindrical axis and keratometer values were statistically compared.

Results

The mean spherical equivalent obtained from the Retinomax K-plus 3 was significantly less hyperopic than that of Canon RK-F1 (p = 0.004) before cycloplegia. When the Bland Altman analysis was performed in comparisons of spherical equivalent values measured with the Retinomax K-plus 3, Canon RK-F1 and cycloplegic retinoscopy, it was seen that almost all of the differences between the measurements remained within the range of ±2 standard deviation. Good agreement was found between Retinomax K-plus 3 and Canon RK-F1 for the Jackson cross-cylinder values at axis 0° and 45°; keratometer values respectively.

Conclusions

The refractive error components were highly correlated between the two instruments and cycloplegic retinoscopy.

Accuracy of the Retinomax K-plus3 in measuring refractive error in a pediatric population

PURPOSE

To compare the Retinomax K-plus3 handheld autorefractor to a retinscopically based refraction performed by a pediatric ophthalmologist.

METHODS

The medical records of 311 children aged 5 months to 17 years who underwent cycloplegic refraction by both autorefractor and a pediatric ophthalmologist on the same day were retrospectively reviewed. Spherical equivalent, vector dioptric distance (VDD) values, and t tests were performed for each metric with an accompanying age-group comparison (<5 years, 5-7 years, 8-10 years, and ≥11 years). Bland-Altman plots were generated to evaluate the agreement between methods.

RESULTS

Overall, the refraction provided by the Retinomax autorefractor was not significantly different in regard to cylinder power and axis. An age-group comparison showed statistically similar readings for all measures of refractive error in children 8-10 years of age. Statistically similar readings were obtained for cylinder power and axis except in children aged 5-7 years. The VDD was statistically different between the two methods for every age group. Bland-Altman plots suggested agreement between the two approaches for the entire cohort with respect to sphere, cylinder, axis, and spherical equivalent.

CONCLUSIONS

In children <18 years of age, there was no clinical difference in the cycloplegic refraction determined by the Retinomax autorefractor when compared to retinoscopy by a pediatric ophthalmologist.

Accuracy of noncycloplegic retinoscopy, retinomax autorefractor, and SureSight vision screener for detecting significant refractive errors

PURPOSE

To evaluate, by receiver operating characteristic (ROC) analysis, the ability of noncycloplegic retinoscopy (NCR), Retinomax Autorefractor (Retinomax), and SureSight Vision Screener (SureSight) to detect significant refractive errors (RE) among preschoolers.

METHODS

Refraction results of eye care professionals using NCR, Retinomax, and SureSight (n = 2588) and of nurse and lay screeners using Retinomax and SureSight (n = 1452) were compared with masked cycloplegic retinoscopy results. Significant RE was defined as hyperopia greater than +3.25 diopters (D), myopia greater than 2.00 D, astigmatism greater than 1.50 D, and anisometropia greater than 1.00 D interocular difference in hyperopia, greater than 3.00 D interocular difference in myopia, or greater than 1.50 D interocular difference in astigmatism. The ability of each screening test to identify presence, type, and/or severity of significant RE was summarized by the area under the ROC curve (AUC) and calculated from weighted logistic regression models.

RESULTS

For detection of each type of significant RE, AUC of each test was high; AUC was better for detecting the most severe levels of RE than for all REs considered important to detect (AUC 0.97-1.00 vs. 0.92-0.93). The area under the curve of each screening test was high for myopia (AUC 0.97-0.99). Noncycloplegic retinoscopy and Retinomax performed better than SureSight for hyperopia (AUC 0.92-0.99 and 0.90-0.98 vs. 0.85-0.94, P ≤ 0.02), Retinomax performed better than NCR for astigmatism greater than 1.50 D (AUC 0.95 vs. 0.90, P = 0.01), and SureSight performed better than Retinomax for anisometropia (AUC 0.85-1.00 vs. 0.76-0.96, P ≤ 0.07). Performance was similar for nurse and lay screeners in detecting any significant RE (AUC 0.92-1.00 vs. 0.92-0.99).

CONCLUSIONS

Each test had a very high discriminatory power for detecting children with any significant RE.

Myopia screening: combining visual acuity and noncycloplegic autorefraction

PURPOSE

To explore the effectiveness of combining uncorrected visual acuity (UCVA) and noncycloplegic autorefraction (NCAR) for large-scale myopia screening in schoolchildren with a high prevalence of myopia.

METHODS

A total of 1687 children aged between 6 and 12 years, from five primary schools in the Baoshan district of Shanghai participated in the study. We measured UCVA and autorefraction before and after cycloplegia by a Topcon KR-8800. We drew receiver operating characteristic curves to achieve the best cutoff points and their corresponding sensitivities and specificities for the UCVA and NCAR, respectively. We then combined the UCVA and NCAR in serial order to explore the optimal criterion and its effectiveness. A specificity of 90% was set to compare the sensitivities among the three tests. The children were divided into three age groups (aged 6 to 7, 8 to 10, 11 to 12 years) to further examine this new method.

RESULTS

A total of 1639 children with an average age of 9.35 (SD, 1.6) years were finally included, among which 428 (26.11%) children were diagnosed as being myopic (spherical equivalent refraction (SER) less than or equal to -0.5 diopters [D]). For the UCVA, the cutoff point is 0.2 logarithm of the minimum angle of resolution (20/32), with a sensitivity and specificity of 63.6% and 94.0%, respectively. For NCAR, the cutoff point is SER less than or equal to -0.75 D, with a sensitivity and specificity of 88.6% and 86.1%, respectively. When UCVA is combined with NCAR, the best cutoff point is UCVA less than or equal to 0 logarithm of the minimum angle of resolution (20/20) and SER less than or equal to -0.75 D, with a sensitivity and specificity of 84.4% and 90.5%, respectively. At a specificity of 90%, the sensitivities are 63.55%, 78.50%, and 84.35%, respectively, for UCVA, NCAR, and the combination test. In all age groups, the combination test had the highest sensitivities among the three tests.

CONCLUSIONS

In a population with a high prevalence of myopia, combining the UCVA and NCAR in serial order achieved higher sensitivity than either of the two tests alone, when specificity was set at 90%.

Utility of an open field Shack-Hartmann aberrometer for measurement of refractive error in infants and young children

PURPOSE

To assess the utility of an open-field Shack-Hartmann aberrometer for measurement of refractive error without cycloplegia in infants and young children.

METHOD

Data included 2698 subject encounters with Native American infants and children aged 6 months to <8 years. We attempted right eye measurements without cycloplegia using the pediatric wavefront evaluator (PeWE) on all participants while they viewed near (50 cm) and distant (2 m) fixation targets. Cycloplegic autorefraction (Rmax [Nikon Retinomax K-plus2]) measurements were obtained for children aged ≥ 3 years.

RESULTS

The success rates of noncycloplegic PeWE measurement for near (70%) and distant targets (56%) significantly improved with age. Significant differences in mean spherical equivalent (M) across near versus distant fixation target conditions were consistent with the difference in accommodative demand. Differences in astigmatism measurements for near versus distant target conditions were not clinically significant. Noncycloplegic PeWE and cycloplegic Rmax measurements of M and astigmatism were strongly correlated. Mean noncycloplegic PeWE M was significantly more myopic or less hyperopic and astigmatism measurements tended to be greater in magnitude compared with cycloplegic Rmax.

CONCLUSIONS

The PeWE tended to overestimate myopia and underestimate hyperopia when cycloplegia was not used. The PeWE is useful for measuring accommodation and astigmatism.

Uncorrected visual acuity and noncycloplegic autorefraction predict significant refractive errors in Taiwanese preschool children

PURPOSE

To investigate the accuracy of uncorrected visual acuity (UCVA), stereopsis, and noncycloplegic autorefraction (NCAR) tests performed by vision-screening technicians and to determine the best referral criteria when using these methods to screen for significant refractive errors in preschool children.

DESIGN

Retrospective, case-control, and cross-sectional study.

PARTICIPANTS

We reviewed 1000 records for a population-based preschool vision-screening program. The target conditions were defined as myopia ≤-3.0 diopters (D), hyperopia ≥ 4.5 D, astigmatism ≥ 2.0 D, and anisometropia ≥ 2.0 D.

METHODS

Receiver operating characteristic (ROC) curve was used to calculate optimal referral cutoff values. The examination results obtained by the vision-screening technicians were compared with those obtained by a pediatric ophthalmologist, which were considered the gold standard.

MAIN OUTCOME MEASURES

The efficacies (sensitivity, specificity, positive predictive value, and negative predictive value) of different tests were evaluated.

RESULTS

In 7.0% (95% confidence interval [CI], 5.3-8.7) of the children, at least 1 eye showed 1 of the target conditions. If only the right eyes were considered, the prevalence of target conditions was 4.2% (95% CI, 2.9-5.5). The ROC curve analysis indicated that the NCAR cylinder test (cutoff value ≥ 0.875 D) was the best test for screening target conditions. With regard to age groups, UCVA ≤ 0.75 (Snellen equivalent) and ≤ 0.85 were the best referral criteria for ages ≤ 4 years and ≥ 5 years, respectively. Combining the UCVA test with the NCAR test (the child was referred after failing both tests) increased specificity without significantly decreasing sensitivity.

CONCLUSIONS

The UCVA and NCAR tests performed by vision-screening technicians are adequately sensitive and specific for preschool vision screening. The ROC curve analysis was used for determining the appropriate screening criteria for these tests, and combining the tests increased their accuracy. The screening criteria should be age dependent. When analyzing the test accuracy in ophthalmic problems, if the disease of interest does not symmetrically (in terms of disease severity and prevalence) involve both eyes, the prevalence based on only 1 eye should be interpreted with caution.

Accuracy of Plusoptix S04 in children and teens

OBJECTIVE

To compare refraction measurements of young patients obtained using Plusoptix S04 with those obtained using cycloplegic retinoscopy.

DESIGN

Cohort study.

PARTICIPANTS

Data were collected from 64 patients (128 eyes), aged 2-19 years.

METHODS

All eyes underwent photorefraction using Plusoptix S04 with or without cycloplegia and cycloplegic retinoscopy. Eyes with a maximum spherical and cylinder range of 7.00 to +5.00 were excluded from the study.

RESULTS

The difference in spherical equivalents between Plusoptix S04 without cycloplegia and cycloplegic retinoscopy was more than ±0.50 D in 70.2% of the eyes. In 100 eyes (78.1%), photorefraction underestimated the hyperopic refractive error. The cylinder powers determined by Plusoptix S04 and cycloplegic retinoscopy were similar. The difference in the spherical equivalents between Plusoptix S04 with cycloplegia and cycloplegic retinoscopy was ±0.50 D in 89.8% of the eyes. In 96 eyes (75%), photorefraction with cycloplegia overestimated the hyperopic refractive error. The difference in cylindrical power determined using Plusoptix S04 with cycloplegia and cycloplegic retinoscopy was statistically significant (paired t test, p <0.009).

CONCLUSIONS

The statistically significant difference in spherical equivalent values obtained using Plusoptix S04 with or without cycloplegia and cycloplegic retinoscopy suggests that Plusoptix S04 is more in evaluating the cylinder power and axis in young patients. Our results also suggest that Plusoptix S04 is not an accurate tool to estimate the refraction in children.

Screening for refractive errors in children: the plusoptiX S08 and the Retinomax K-plus2 performed by a lay screener compared to cycloplegic retinoscopy

PURPOSE

To evaluate the performance of the autorefractor Retinomax K-plus2 and the photoscreener plusoptiX S08 in measuring refractive errors by comparing them with cycloplegic retinoscopy (CR) and to assess limitations associated with their use.

METHODS

Cross-sectional study to compare data from CR, performed by an orthoptist, to data from Retinomax K-plus2 and plusoptiX S08 performed by a lay screener. Sensitivity and specificity for the detection of significant refractive errors were determined according to American Academy of Pediatric Ophthalmology and Strabismus criteria.

RESULTS

Two hundred children were included, with a mean age of 5.2 ± 2.6 years (3 months to 11 years). Compared to CR, the plusoptiX S08 showed a mean difference of -1.13 ± 1.25 D (95% limits of agreement [LOA], -3.59 to +1.32) for spherical equivalent (SE) and -0.23 ± 0.53 D (LOA, -1.28 to +0.81) for the cylinder. Mean difference for the Retinomax K-plus2 before cycloplegia was -0.08 ± 0.58 D (LOA, -1.23 to +1.06) for SE and 0.03 ± 0.38 D (LOA, -0.72 to +0.78) for the cylinder; after cycloplegia -2.11 ± 1.64 D (LOA, -5.33 to +1.10) for SE and -0.06 ± 0.47 D (LOA, -0.98 to +0.86) for the cylinder. Sensitivity for detecting hyperopia >3.5 D with the plusoptiX S08 was 33.3%, the Retinomax before cycloplegia 31.0% and after cycloplegia 84.6% and high for detecting myopia, astigmatism, and anisometropia.

CONCLUSIONS

Retinomax K-plus2 and plusoptiX S08 have high sensitivity for the detection of myopia, astigmatism, and anisometropia compared to cycloplegic retinoscopy; however, when used without cycloplegia, hyperopia is underestimated.

Noncycloplegic Photorefractive Screening in Pre-School Children with the “PowerRefractor” in a Pediatric Practice

PURPOSE

To provide a framework for typical refractive development, as measured without cycloplegia with a commercial infrared photorefractor. To evaluate the usefulness of the screening for refractive errors, we retrospectively analyzed the data of a large number of unselected children of different ages in a pediatric practice in Tuebingen, Germany.

METHODS

During the standard regular preventive examinations that are performed in 80% to 90% of the young children in Germany by a pediatrician (the German "U1 to U9" system), 736 children were also measured with the first generation PowerRefractor (made by MCS, Reutlingen, Germany, but no longer available in this version). Of those, 172 were also measured with +3 D spectacles to find out whether this helps detect hyperopia. Children with more than +2 D of hyperopia or astigmatism, more than 1.5 D of anisometropia, or more than 1 D of myopia in the second year of life were referred to an eye care specialist. The actions taken by the eye care specialist were used to evaluate the merits of the screening.

RESULTS

The average noncycloplegic spherical refractive errors in the right eyes declined linearly from +0.93 to +0.62 D over the first 6 years (p < 0.001)-between 1.5 and 0.5 D less hyperopic than in published studies with cycloplegic retinoscopy. As expected, +3 D spectacle lenses moved the refractions into the myopic direction, but this shift was not smaller in hyperopic children. The average negative cylinder magnitudes declined from -0.89 to 0.48 D (linear regression: p < 0.001). The J0 components displayed high correlations in both eyes (p < 0.001) but the J45 components did not. The average absolute anisometropias (difference of spheres) declined from 0.37 to 0.23 (linear regression: p < 0.001). Of the 736 children, 85 (11.5%) were referred to an eye care specialist. Of these, 52 received spectacles (61.2%), 14 (16.4%) were identified as "at risk" and remained under observation, and 18 (21.2%) were considered "false-positive."

CONCLUSIONS

Non cycloplegic photorefraction provides considerably less hyperopic readings than retinoscopy under cycloplegia. Additional refractions performed through binocular +3-D lenses did not facilitate detection of hyperopia. With the referral criteria above, 11% of the children were referred to an eye care specialist, but with a 20% false-positive rate. The screening had some power to identify children at risk but the number of false-negatives remained uncertain.

A comparison of autorefraction and subjective refraction with and without cycloplegia in primary school children

PURPOSE

To evaluate the accuracy of autorefraction using three autorefractors comparing to subjective refraction in diagnosing refractive error in children.

DESIGN

A cross-sectional study.

METHODS

setting: Community based study. study population: 117 children sampled from primary schools. procedures: All subjects underwent autorefraction using three auto refractors and subjective refraction with and without cycloplegia. main outcome measures: Spherical power, cylindrical power, and spherical equivalence (SE).

RESULTS

Without cycloplegia, the mean SE were significantly different for Retinomax K plus 2 (-1.55 diopters, SD 2.37 diopters; 95% CI -1.98 to -1.12; P < .0001) and Canon RF10 (-1.11 diopters; SD 2.61 diopters; 95% CI -1.59 to -0.64; P = .0023) compared with monocular subjective refraction (-0.80 diopters; SD 2.25 diopters; 95% CI -1.21 to -0.35). Mean SE was significantly different for Grand Seiko WR5100K (-0.79 diopters; SD 2.40 diopters; 95% CI -1.23 to -0.35; P = .0002) compared with binocular subjective refraction (-0.62 diopters; SD 2.51 diopters; 95% CI -1.07 to -0.16). With cycloplegia, there was no significant difference in mean SE between refraction methods. Sensitivity and specificity results for the diagnosis of myopia: Without cycloplegia: Retinomax K plus 2 (sensitivity 1.0, specificity 0.51); Canon RF10 (sensitivity 0.92, specificity 0.81); and Grand Seiko WR5100K (sensitivity 0.91, specificity 0.98). With cycloplegia: Retinomax K plus 2 (sensitivity 0.97, specificity 0.99); Canon RF10 (sensitivity 0.97, specificity 0.96); and Grand Seiko WR5100K (sensitivity 1.0, specificity 0.97).

CONCLUSIONS

Under noncycloplegic conditions, all three autorefractors have a tendency towards minus over correction in children resulting in over diagnosis of myopia. However autorefractors were accurate under cycloplegic conditions.

Comparisons of the Handheld Autorefractor, Table-Mounted Autorefractor, and Subjective Refraction in Singapore Adults

PURPOSE

The purpose of this article was to compare the Retinomax with the table-mounted autorefractor and subjective refraction in Singapore adults.

METHODS

Adults (n = 100) attending a tertiary eye hospital clinic were examined by an optometrist. First, subjective refraction testing was performed using a trial lens set, followed by handheld autorefractor tests using the Nikon Retinomax and the table-mounted autorefractor (Topcon RM8000B). Spherical equivalent and vector components of astigmatism were analyzed: J0 (Cartesian astigmatism) and J45 (oblique astigmatism).

RESULTS

The Retinomax autorefractor readings (mean = -4.69 D) were more minus compared with the table-mounted autorefractor (mean = -4.05 D) and subjective refraction (mean = -3.90 D). There were significant differences in J0 and J45 for comparisons between subjective refraction and Retinomax autorefraction, and table-mounted autorefraction and Retinomax autorefraction.

CONCLUSION

The Retinomax autorefractor measures were more minus compared with the table-mounted autorefractor and subjective refraction. The Retinomax autorefractor is not recommended for research purposes, unless in remote inaccessible areas where a portable instrument is necessary and cycloplegia is not possible.

The influence of cycloplegia in objective refraction

The purpose of this study was to compare refractions measured with an autorefractor and by retinoscopy with and without cycloplegia. The objective refractions were performed in 199 right eyes from 199 healthy young adults with a mean age of 21.6 +/- 2.66 years. The measurements were performed first without cycloplegia and repeated 30 min later with cycloplegia. Data were analysed using Fourier decomposition of the power profile. More negative values of component M and J(0) were given by non-cycloplegic autorefraction compared with cycloplegic autorefraction (p < 0.0001). However more positive values for the J(45) vector were given by non-cycloplegic autorefraction, although this difference was not statistically significant (p = 0.233). By retinoscopy, more negative values of component M were obtained with non-cycloplegic retinoscopy (p < 0.0001); for the cylindrical vectors J(0) and J(45) the retinoscopy without cycloplegia yields more negative values (p = 0.234; p = 0.112, respectively). Accepting that differences between cycloplegic and non-cycloplegic retinoscopy are only due to the accommodative response, the present results confirm that when performed by an experienced clinician, retinoscopy is a more reliable method to obtain the objective starting point for refraction under non-cycloplegic conditions.

Screening for amblyogenic factors in preschool children with the retinomax hand-held refractor: do positive children have amblyopia and is treatment efficacious?

PURPOSE

To determine the visual acuity (VA) in a group of preschool children who were true positives for refractive screening (positive group) in order to compare it with the VA of a sample of children without any refractive anomaly (control group); also, to investigate if true-positive treated children can achieve the VA of the control group within what delay.

METHODS

Fifty seven children without any refractive anomaly were tested with the VA child chart if the Nidek SCP 670 projector; 47 children presenting with the refractive anomalies were tested with the same chart. A Kruskal Wallis exact test for singly ordered tables were used to compare VA between those groups and a non-parametric Wilcoxon test for paired samples was used to compare pre- and post-treatment VA in 27 children of the positive group. The mean time necessary to achieve the post-treatment VA was calculated.

RESULTS

Median VA: 20/20 in the control group, 20/33 in the positive group. The VA difference between the two pre- and post-treatment VA are highly significant. Among the 27 treated children, pre-treatment median VA was 20/50, post-treatment 20/20. The differences between the pre- and post-treatment VA was 9 months.

CONCLUSION

The positive group had a significantly lower VA than the control group. In the treated group, treatment initiated at a mean age of 4 years resulted in an increase in VA to that of the control group after an average time of 9 months, encouraging early screening and treatment before VA is measureable in order to shorten this delay.

Comparison between two hand-held autorefractors: the Sure-Sight and the Retinomax

PURPOSE

To compare the results of manifest refraction obtained with two different hand-held autorefractors (Sure-Sight, Welch Allyn Co. and Retinomax 1, Nikon Inc.) and with the Topcon RMA 6000 on-table autorefractor in order to estimate any potential bias between these refractometers and to compare the diagnostic performances of these two hand-held autorefractors as screening devices.

METHODS

Ninety-eight children were refracted under manifest conditions with the three above-mentioned refractometers and under cycloplegic conditions with the Topcon on-table autorefractor, or by means of retinoscopy. The agreement between the manifest measurements obtained with the three different autorefractors was studied using the method of Bland and Altman. The validity of several thresholds of manifest refractive anomalies as measured with the Sure-Sight and with the Retinomax was estimated by receiver operating characteristic (ROC) curves using cycloplegic measures as reference. results There is a spherical positive bias of 1 D between the Sure-Sight and the Retinomax and better agreement between the Topcon and the Retinomax. The surface area indexes of the ROC curves and the diagnostic performances in term of sensitivity and specificity are better with the Retinomax in cases of hyperopia, astigmatism and anisometropia. For myopia, the Sure-Sight has better performance.

CONCLUSIONS

The results suggest that either device may be sufficient for assessing refractive errors in children in a screening setting. However, because of a bias between both refractometers in measuring the sphere, distinctive referral criteria must be chosen for the detection of hyperopia and myopia. The diagnostic performance is slightly in favor of the Retinomax.

Examination of preschool children for ametropia: first experiences using a new hand-held autorefractor

INTRODUCTION

Over the last decades, various methods have been investigated for preschool screening for amblyogenic ametropia. The SureSight is a new hand-held wavefront-analyzing autorefractor designed for screening.

METHODS

A total of 338 children (3 1/2 - 4 1/2 years-old) were examined in their kindergartens without cycloplegia using the new instrument. Of these, 56 had a cycloplegic retinoscopy as a reference measurement. Hyperopia > or =3 dpt, myopia > or =1 dpt, astigmatism > or =1 dpt and anisometropia > or =1 dpt were considered amblyogenic ametropia.

RESULTS

Testability was 99.4%. Accuracy was high for cylinder power and axis but poor for the spherical equivalent. Sensitivity was 41% for the detection of amblyogenic hyperopia, 95% for astigmatism and 75% for anisometropia, with specificity values of 92, 79 and 73%.

CONCLUSION

The high testability and accuracy for cylinder power and axis are the strong points. The poor accuracy for the spherical equivalent is probably caused by the lack of cycloplegia. At present, non-cycloplegic autorefractor screening cannot be recommended due to the low specificity. Our findings support the advice that objective refraction in childhood must be performed with cycloplegia.

Corneal and lenticular components of total astigmatism in a preschool sample

PURPOSE

To examine the contribution of corneal and lenticular components to total astigmatism in preschool low and high astigmats to determine whether there was any compensation for high astigmatism by the lenticular component.

METHODS

Cycloplegic refractive and keratometric measures using the Retinomax K-Plus (Nikon Inc., Melville, NY) were conducted on 129 children (mean age, 51.1 +/- 8.4 mo) in Oxford County, Canada. We divided the sample into high astigmats (total cylinder > or =1 D; mean, 1.38 +/- 0.43 D; n = 29) and normal astigmats (total cylinder < or =0.75 D; mean, 0.22 +/- 0.20 D; n = 100). Measures of total and corneal cylinder were transposed into J0 and J45 components, where positive and negative J0 values quantified with-the-rule (WTR) and against-the-rule astigmatisms, respectively, and J45 quantified oblique astigmatism.

RESULTS

WTR astigmatism was dominant in both the high and normal astigmatic group. J0 and J45 components of corneal astigmatism were highly correlated with total astigmatism in high astigmats, whereas only J0 was significantly correlated with total astigmatism in normal astigmats. Although the magnitude of total and corneal cylinder was significantly greater in high astigmats, overall lenticular cylinder was similar in both groups. However, the Fourier transforms showed high astigmats to have significantly lower lenticular J0 and higher lenticular J45 than the normal astigmats.

CONCLUSIONS

Astigmatism in 3- to 5-year-old children is primarily corneal. In preschool children, the lens does not vary in response to high amounts of corneal WTR astigmatism, and in fact, it increases the oblique astigmatism component when the corneal component is high. In high astigmats, lenticular astigmatism contributes to both J0 and J45 components, whereas the corneal contribution is primarily J0.