The accommodative lag of the young hyperopic patient

Emmetropization in highly hyperopic infants: A randomized clinical trial of partial refractive correction

SIGNIFICANCE

Highly hyperopic infants are at greater risk for not undergoing emmetropization and later developing conditions such as strabismus, amblyopia, and early literacy and reading problems. An early intervention consisting of partial hyperopic correction and encouragement of accommodation may influence the rate of emmetropization in these high-risk infants.

PURPOSE

This study aimed to determine if moderate spectacle partial correction (3.00 D cut from cycloplegic) and visual exercises to promote accommodation enhance emmetropization (reaching ≤+3.00 D) in highly hyperopic (≥+5.00 D to ≤+7.00 D) 3-month-old infants compared with no treatment (observation).

METHODS

Thirty-five highly hyperopic 3-month-old infants (57% female) were randomized to observation or treatment (clinicaltrials.gov; NCT03669146). Primary analysis compared the mean hyperopia at 18 months of age in treated versus untreated participants. Data were also modeled using proportional hazards survival analysis (time to reach ≤+3.00 D).

RESULTS

There was no significant difference in refractive error at 18 months of age between infants in the treated (+1.6 ± 0.6 D) and observation groups (+1.2 ± 0.7 D; p = 0.23) but treatment affected the rate of emmetropization depending on baseline hyperopia (p = 0.01). At 12 months of age, treated infants had similar refractive errors regardless of baseline hyperopia but untreated infants at 12 months underwent faster emmetropization if their baseline hyperopia was <+5.50 D and slower emmetropization if it was >+5.50 D.

CONCLUSIONS

Partial hyperopic refractive correction with accommodative exercises in highly hyperopic infants did not affect average refractive error at 18 months. However, treatment affected the rate of emmetropization and how long it took to reach ≤+3.00 D. Treatment slowed the rate of emmetropization at lower levels of initial hyperopia but may enhance emmetropization at higher levels.

How Do Most Young Moderate Hyperopes Avoid Strabismus?

Purpose

Uncorrected hyperopic children must overcome an apparent conflict between accommodation and vergence demands to focus and align their retinal images. This study tested hypotheses about simultaneous accommodation and vergence performance of young hyperopes to gain insight into ocular motor strategies used to maintain eye alignment.

Methods

Simultaneous eccentric photorefraction and Purkinje image tracking were used to assess accommodative and vergence responses of 26 adult emmetropes (AE) and 94 children (0-13 years) viewing cartoons. Children were habitually uncorrected (CU) (spherical equivalent refractive error [SE] -0.5 to +4 D), corrected and aligned (CCA), or corrected with a history of refractive esotropia (CCS). Accommodative and vergence accuracy, dissociated heterophoria, and vergence/accommodation ratios in the absence of retinal disparity cues were measured for 33- and 80-cm viewing distances.

Results

In binocular viewing, median accommodative lags for 33 cm were 1.0 D (AE), 1.33 D (CU), 1.25 D (CCA), and 1.0 D (CCS). Median exophorias at 80 and 33 cm were 1.2 and 4.5 pd (AE), 0.8 and 2.5 pd (CU), and 0 and 1.2 pd (CCA), respectively. Without disparity cues, most response vergence/accommodation ratios were between 1 and 2 meter angle/D (∼5-10 pd/D) (69% of AE, 44% of CU, 60% of CCA, and 50% of CCS).

Conclusions

Despite apparent conflict in motor coupling, uncorrected hyperopes were typically exophoric and achieved adultlike accuracy of both vergence and accommodation simultaneously, indicating ability to compensate for conflicting demands rather than bias to accurate vergence while tolerating inaccurate accommodation. Large lags and esophoria are therefore atypical. This analysis provides normative guidelines for clinicians and a deeper mechanistic understanding of how hyperopes avoid strabismus.

Accuracy and stability of accommodation and vergence responses during sustained near tasks in uncorrected hyperopes

This study investigated the accuracy and stability of accommodative and vergence functions in children with and without hyperopia while engaged in two sustained near tasks. The sustained accommodative and vergence characteristics of participants without refractive correction (n = 92, aged 5-10 years) with and without hyperopia (defined as cycloplegic retinoscopy ≥  + 1.00D and less than + 5.00D) were measured using eccentric infrared photorefraction (PowerRef 3; PlusOptix, Germany). Binocular measures of accommodation and eye position were recorded while participants engaged in 2 tasks at 25 cm for 15 min each: (1) reading small print on an Amazon Kindle and (2) watching an animated movie on liquid crystal display screen. Comprehensive visual assessment, including measurement of presenting visual acuity, amplitude of accommodation, and stereoacuity was conducted. The magnitude of accommodative and vergence responses was not related to refractive error (P > 0.05). However, there were inter-task differences in the accuracy and stability of the accommodative responses across refractive groups (P < 0.05). The relationship between accommodation and vergence was not significant in both tasks (P > 0.05). However, increased accommodative and vergence instabilities were associated with total accommodative response (P < 0.05). Despite having greater accommodative demand, uncorrected hyperopes accommodate comparably to emmetropic controls. However, uncorrected hyperopes have increased instabilities in their accommodative and vergence responses, which may adversely impact their visual experience.

Validation of the PowerRef 3 for Measuring Accommodation: Comparison With the Grand Seiko WAM-5500A Autorefractor

Purpose

This validation study examines the PowerRef 3 as a method for measuring accommodation objectively. We assess agreement with refractive measurements obtained simultaneously by the Grand Seiko WAM-5500A autorefractor.

Methods

Refractive measurements were recorded simultaneously using the PowerRef 3 and WAM-5500A in 32 noncyclopleged participants aged 15 to 46 years. Accommodative states were recorded for 10 seconds at six accommodative demands (5 diopters [D], 4 D, 3 D, 2.5 D, 2 D, and 0 D) while participants fixated a high-contrast Maltese cross. WAM-5500A measurements were converted to power in the vertical meridian for comparison with PowerRef 3 data. Dioptric difference values were computed, and agreement was assessed using Bland-Altman plots with 95% limits of agreement (LOA) and intraclass correlation coefficient analyses.

Results

The mean absolute dioptric differences measured 0.14 D or less across accommodative demands. Analyses showed an excellent intraclass correlation coefficient across the tested demands (0.93). Bland-Altman plots indicated a bias of -0.02 D with 95% LOA of -1.03 D to 0.99 D. The 95% LOA was smallest for the 3 D demand (-0.71 D to 0.64 D), and largest at 5 D demand (-1.51 D to 1.30 D).

Conclusions

The mean dioptric differences between the PowerRef 3 and WAM-5500A autorefractor were small and not clinically significant. While some variability in agreement was observed depending on the tested demand, the PowerRef 3 demonstrated good agreement with the WAM-5500A.

Translational Relevance

The PowerRef 3 may be used to obtain objective measures of accommodation both monocularly and binocularly and provides a more flexible method, especially in pediatric populations.

The Impact of Hyperopia on Academic Performance Among Children: A Systematic Review

PURPOSE

To assess the impact of uncorrected hyperopia and hyperopic spectacle correction on children's academic performance.

DESIGN

Systematic review and meta-analysis.

METHODS

We searched 9 electronic databases from inception to July 26, 2021, for studies assessing associations between hyperopia and academic performance. There were no restrictions on language, publication date, or geographic location. A quality checklist was applied. Random-effects models estimated pooled effect size as a standardized mean difference (SMD) in 4 outcome domains: cognitive skills, educational performance, reading skills, and reading speed. (PROSPERO registration: CRD-42021268972).

RESULTS

Twenty-five studies (21 observational and 4 interventional) out of 3415 met the inclusion criteria. No full-scale randomized trials were identified. Meta-analyses of the 5 studies revealed a small but significant adverse effect on educational performance in uncorrected hyperopic compared to emmetropic children {SMD -0.18 [95% confidence interval (CI), -0.27 to -0.09]; P < 0.001, 4 studies} and a moderate negative effect on reading skills in uncorrected hyperopic compared to emmetropic children [SMD -0.46 (95% CI, -0.90 to -0.03); P = 0.036, 3 studies]. Reading skills were significantly worse in hyperopic than myopic children [SMD -0.29 (95% CI, -0.43 to -0.15); P < 0.001, 1 study]. Qualitative analysis on 10 (52.6%) of 19 studies excluded from meta-analysis found a significant (P < 0.05) association between uncorrected hyperopia and impaired academic performance. Two interventional studies found hyperopic spectacle correction significantly improved reading speed (P < 0.05).

CONCLUSIONS

Evidence indicates that uncorrected hyperopia is associated with poor academic performance. Given the limitations of current methodologies, further research is needed to evaluate the impact on academic performance of providing hyperopic correction.

Correction of Low-Moderate Hyperopia Improves Accommodative Function for Some Hyperopic Children During Sustained Near Work

Purpose

This study investigated whether refractive correction improved accommodative function of hyperopic children while engaged in two sustained near activities.

Methods

Sustained accommodative function of 63 participants (aged 5–10 years) with varying levels of uncorrected hyperopia (>/= +1.00 D and < + 5.00 D spherical equivalent in the least hyperopic eye) was measured using eccentric infrared photorefraction (PowerRef 3; PlusOptix, Germany). Binocular accommodation measures were recorded while participants engaged in 2 tasks at 25 cm for 15 minutes each: an “active” task (reading small print on an Amazon Kindle), and a “passive” task (watching an animated movie on liquid crystal display [LCD] screen). Participants also underwent a comprehensive visual assessment, including measurement of presenting visual acuity, prism cover test, and stereoacuity. Reading speed was assessed with and without hyperopic correction. Refractive error was determined by cycloplegic retinoscopy.

Results

Hyperopic refractive correction significantly improved accuracy of accommodative responses in both task (pairwise comparisons: t = −3.70, P = 0.001, and t = −4.93, P < 0.001 for reading and movie tasks, respectively). Accommodative microfluctuations increased with refractive correction in the reading task (F_(1,61) = 25.77, P < 0.001) but decreased in the movie task (F_(1,59) = 4.44, P = 0.04). Reading speed also significantly increased with refractive correction (F_(1,48) = 66.32, P < 0.001).

Conclusions

Correcting low-moderate levels of hyperopia has a positive impact on accommodative performance during sustained near activity in some schoolchildren. For these children, prescribing hyperopic correction may benefit performance in near vision tasks.

Accuracy of WASCA Aberrometer Refraction Compared to Manifest Refraction and Cycloplegic Refraction in Hyperopia Measurement

Purpose

To explore the agreement between the wavefront supported custom ablation (WASCA) aberrometer and manifest refraction (MR) and cycloplegic refraction (CR) in hyperopia testing.

Methods

Ninety eyes of 90 hyperopic patients (spherical equivalent ≥ +0.5 D) were evaluated; MR, CR, and WASCA refraction (WR) were performed consecutively. Analysis pupil size was 6.0 mm in WASCA measurement using the Seidel method. The conventional notation was transferred into vector components for analysis, i.e., spherical equivalent (M) and two cross-cylinders at axis 0° (J₀) and axis 45° (J₄₅). Bland-Altman plots were used to test the agreement between the two measurements.

Results

The mean Ms obtained with MR and CR were 3.23 ± 1.74 D and 4.04 ± 2.04 D, respectively (P < 0.001), and the correlation was high (r = 0.90, P < 0.001). The WR was highly correlated with MR and CR in terms of M (r = 0.89, 0.87), but not significantly correlated in J₀ and J₄₅. The total dioptric power vector error was 0.18 ± 1.00 D between WR and MR and −0.64 ± 1.03 D between WR and CR. The limits of agreement of all vector components were beyond ± 1.0 D. With hyperopia level increase, WR tended to overestimate MR (P = 0.04), whereas WR always underestimated CR.

Conclusions

WASCA could act as a reference of subjective refraction in hyperopia measurement, the exchangeability is not fully applicable.

Translational Relevance

WASCA can provide an alternative for objective refraction in hyperopia measurement.

Diagnosis of Accommodative Spasm Aided by Handheld Photoscreener

We report a case of accommodative spasm in an 8-year-old girl discovered by handheld photoscreener. The patient was found to have a Chiari I malformation, and managed with atropine drops and reading glasses, ultimately with improvement in her symptoms. We believe this to be the first case of accommodative spasm diagnosis aided by the use of a handheld photoscreener.

Accommodation and its role in myopia progression and control with soft contact lenses

PURPOSE

To examine the impact of contact lens optical design on accommodative behaviour of children and the correlation between myopia progression and the accommodative response of the eye while wearing a contact lens designed for myopia control.

METHODS

A post-hoc analysis was conducted on data from a previously published myopia control trial. A total of 109 subjects (aged 8 to 11 years, myopia: -0.75 to -4.00 D) wore either a Control (single-vision, n = 57) or a Test (with positive spherical aberration, +SA, n = 52) soft contact lens, binocularly for 1 year. Accommodative response was measured as the subject observed targets at -1.00 to -4.00 D vergence using the Grand Seiko WAM-5500 open-field autorefractor (www.grandseiko.com). Slope of accommodative response (SAR) as well as distance and near phoria and stimulus accommodative convergence/accommodation (AC/A) were compared between each group at baseline without study lenses and at 1-week and 1-year visits with study lenses. The SAR was also compared to changes in axial length (AL) and spherical equivalent cycloplegic auto refraction (SECAR).

RESULTS

At baseline, there was no significant difference in SAR between the two study groups (ΔSAR = -0.039, p = 0.84). At 1 week, mean SAR of the Test group was significantly less than for the Control group (ΔSAR = -0.203, p < 0.0001), an effect that persisted to 1 year (ΔSAR = -0.129, p < 0.0001). In the Test group, greater SAR was associated with less change in AL (regression coefficient: -0.59 mm, p < 0.0001) and SECAR (regression coefficient: 1.12 D, p = 0.006) at 1 year. In the Control group, associations between SAR and change in AL and SECAR were not statistically significant. Compared to the Control group, eyes of the Test group appeared to be more exophoric with study lenses, however, the difference between the two groups was only significant at 1 week for distance phoria and 1 year for near phoria.

CONCLUSION

The soft contact lens with +SA for controlling myopia progression resulted in an apparent decrease in mean accommodation. Within the Test group, reduced accommodative response correlated with greater myopia progression, suggesting some subjects in the Test group utilised the +SA for near viewing, inducing hyperopic defocus at the retina. Accordingly, the potential impact of a lens optics on accommodative function should be considered during design of myopia control lenses.

Validity of the Spot Vision Screener in detecting vision disorders in children 6 months to 36 months of age

PURPOSE

To evaluate the Spot Vision Screener in detecting targeted vision disorders compared to cycloplegic retinoscopy in children <3 years of age.

METHODS

Children, ages 6 months to 36 months underwent vision screening using the Spot Vision Screener. Results were compared to results of comprehensive eye examinations. Validity of the Spot was evaluated by calculating the area under the curve (AUC); the receiver operating characteristics (ROC) were used to determine optimal sensitivity and specificity for detection of targeted vision disorders.

RESULTS

A total of 249 children were included. The AUC for detecting targeted vision disorders as defined by the study specific criteria using the Spot was 0.790. Compared to cycloplegic retinoscopy, the Spot underestimated hyperopia by 1.02 D (95% CI, 0.86-1.17 D). For hyperopia ≥4.5 D spherical equivalent (n = 10), the mean difference between the Spot and cycloplegic retinoscopy was 3.46 D (95% CI, 1.95-4.98 D). In contrast, the Spot overestimated astigmatism compared to cycloplegic retinoscopy (-1.00 D vs -0.48 D; P < 0.001) by -0.52 D (95% CI, 0.43-0.62 D).

CONCLUSIONS

The Spot Vision Screener showed good overall validity in detecting targeted vision disorders. It was within 0.5 D and 1 D of cycloplegic retinoscopy with regard to low hyperopia and astigmatism. Higher hyperopic spherical equivalent refractive errors showed larger differences in mean values between the Spot and cycloplegic retinoscopy.

Impact of Cognitive Demand during Sustained Near Tasks in Children and Adults

SIGNIFICANCE

These results demonstrate that accommodation in children is more accurate and less variable when performing a sustained near task with increased cognitive demand. In addition, children with increased uncorrected hyperopia have less stable accommodative responses, which may have visual implications during sustained near tasks.

PURPOSE

This study investigated accommodative accuracy (lag) and variability during sustained viewing for passive and active tasks in children and adults with emmetropia and uncorrected hyperopia.

METHODS

Lag and variability (root mean square [RMS] and low-frequency component) were measured in 54 children aged 3 to younger than 10 years with mean spherical equivalent of +1.31 ± 1.05 diopters (D) (range, -0.37 to +4.58 D) and 8 adults aged 22 to 32 years with mean spherical equivalent +0.65 ± 0.62 D (range, -0.13 to +1.15 D). Subjects viewed 20/50 stimuli at 33 cm during both a 10-minute passive and active task. Group 1 (<6 years or nonreaders) viewed shapes; group 2 (≥6 years and reading) and adults read passages.

RESULTS

Groups 1 and 2 had larger lags, RMS, and low-frequency component for passive versus active tasks (P < .001). Lag and RMS did not differ between tasks in adults (P > .05), but low-frequency component was larger during passive viewing (P = .04). Group 1 had significantly higher RMS and low-frequency component than group 2 and the adults in the passive condition had greater low-frequency component in the active condition. In children, hyperopia was independently associated with RMS and low-frequency component under passive (RMS 95% confidence interval [CI], 0.04 to 0.15; low-frequency component 95% CI, 0.00011 to 0.00065) and active (RMS 95% CI, 0.001 to 0.06; 95% CI, 0.000014 to 0.00023) viewing.

CONCLUSIONS

Accommodation is more accurate and less variable when children are engaged in the task. Children also have more variable accommodation than adults. In addition, children with greater hyperopia have more variable accommodation during sustained near tasks.

Validity of the +1.50 plus lens screening test as a predictor of uncorrected moderate hyperopia

PURPOSE

Screening for uncorrected hyperopia in school children is important given its association with poorer visual function and academic performance. However, standard distance visual acuity screening may not detect low to moderate hyperopia. The plus lens test is used to screen for hyperopia in many school screening protocols, but has not been well validated. The current study investigated the effectiveness of the plus lens test to identify hyperopia in school children.

METHODS

Participants included Grade 2 school children. Monocular distance visual acuity (logMAR letter chart) was measured unaided, and then through a +1.50D lens, known as the plus lens test. Cycloplegic refraction was undertaken to classify moderate hyperopia (≥+2.00D). Sensitivity, specificity, positive predictive values (PPV) and negative predictive values (NPV) were calculated for commonly used cut-offs for the plus lens test: 6/6, 6/9 and less than two lines difference between unaided acuity and acuity through the plus lens test.

RESULTS

The sample included 59 children (mean age 7.2 ± 0.4 years). Fourteen (24%) children were classified as having uncorrected hyperopia. The sensitivity and specificity of the +1.50 plus lens test for identifying hyperopia were 0% and 98% respectively for a 6/6 cut-off, 29% and 91% for 6/9 cut-off, and 50% and 76% for a <2 line reduction between unaided acuity and acuity through the plus lens test. Receiver Operating Curve (ROC) analysis revealed area under curves of 0.69 based on acuity through the plus lens test, and 0.65 for a reduction in acuity through the plus lens test.

CONCLUSIONS

The plus lens test has low sensitivity for detecting uncorrected hyperopia using traditional cut-offs of 6/9 or better. This raises questions about the role of the plus lens test in school screening batteries.

HGF-rs12536657 and Ocular Biometric Parameters in Hyperopic Children, Emmetropic Adolescents, and Young Adults: A Multicenter Quantitative Trait Study

Introduction

Even though ocular refractive state is highly heritable and under strong genetic control, the identification of susceptibility genes remains a challenge. Several HGF (hepatocyte growth factor) gene variants have been associated with ocular refractive errors and corneal pathology.

Purpose

Here, we assess the association of an HGF gene variant, previously reported as associated with hyperopia, and ocular biometric parameters in a multicenter Spanish cohort.

Methods

An observational prospective multicenter cross-sectional study was designed, including a total of 403 unrelated subjects comprising 188 hyperopic children (5 to 17 years) and 2 control groups: 52 emmetropic adolescents (13 to 17 years) and 163 emmetropic young adults (18 to 28 years). Each individual underwent a comprehensive eye examination including cycloplegic refraction, and topographic and ocular biometric analysis. Genomic DNA was extracted from oral swabs. HGF single nucleotide polymorphism (SNP) rs12536657 was genotyped. Genotypic, allelic, and logistic regression analyses were performed comparing the different groups. A quantitative trait association test analyzing several biometric parameters was also performed using generalized estimating equations (GEEs) adjusting for age and gender.

Results

No association between rs12536657 and hyperopia was found through gender-adjusted logistic regression comparing the hyperopic children with either of the two control groups. Significant associations between mean topographic corneal curvature and rs12536657 for G/A (slope = +0.32; CI 95%: 0.04-0.60; p=0.023) and A/A (slope = +0.76; CI 95%: 0.12-1.40; p=0.020) genotypes were observed with the age- and gender-adjusted univariate GEE model. Both flat and steep corneal topographic meridians were also significantly associated with rs12536657 for the G/A and A/A genotypes. No association was found between rs12536657 and any other topographic or biometric measurements.

Conclusions

Our results support a possible role for HGF gene variant rs12536657 in corneal curvature in our population. To our knowledge, this is the first multicenter quantitative trait association study of HGF genotypes and ocular biometric parameters comprising a pediatric cohort.

Blur Detection, Depth of Field, and Accommodation in Emmetropic and Hyperopic Children

SIGNIFICANCE

Our results demonstrate that blur detection thresholds are elevated in young children compared with adults, and poorer blur detection thresholds are significantly correlated with the magnitude of accommodative microfluctuations. Given that accommodative microfluctuations are greater with greater accommodative responses, these findings may have implications for young uncorrected hyperopes.

PURPOSE

This study investigated the association between subjective blur detection thresholds and accommodative microfluctuations in children 3 years to younger than 10 years old and adults.

METHODS

Blur detection thresholds were determined in 49 children with habitually uncorrected refractive error (+0.06 to +4.91 diopters [D] spherical equivalent) and 10 habitually uncorrected adults (+0.08 to +1.51 D spherical equivalent) using a custom blur chart with 1° sized optotypes at 33 cm. Letters were blurred by convolution using a Gaussian kernel (SDs of 0.71 to 11.31 arc minutes in √2 steps). Subjective depth of field was determined in subjects 6 years or older and adults. Accommodative microfluctuations, pupils, and lag were measured using infrared photorefraction (25 Hz).

RESULTS

Children had greater blur detection thresholds (P < .001), accommodative microfluctuations (P = .001), and depth of field (P < .001) than adults. In children, increased blur detection thresholds were associated with increased accommodative microfluctuations (P < .001), increased uncorrected hyperopia (P = .01), decreased age (P < .001), and decreased pupil size (P = .01). In a multiple linear regression analysis, blur detection thresholds were associated with accommodative microfluctuations (P < .001) and age (P < .001). Increased accommodative microfluctuations were associated with increased uncorrected hyperopia (P = .004) and decreased pupil size (P = .003) and independently associated with uncorrected hyperopia (P = .001) and pupil size (P = .003) when controlling for age and lag.

CONCLUSIONS

Children did not have adult-like blur detection thresholds or depth of field. Increased accommodative microfluctuations and decreased age were independently associated with greater blur detection thresholds in children 3 years to younger than 10 years. Larger amounts of uncorrected hyperopia in children appear to increase blur detection thresholds because the greater accommodative demand and resulting response increase accommodative microfluctuations.

Attention and Visual Motor Integration in Young Children with Uncorrected Hyperopia

SIGNIFICANCE

Among 4- and 5-year-old children, deficits in measures of attention, visual-motor integration (VMI) and visual perception (VP) are associated with moderate, uncorrected hyperopia (3 to 6 diopters [D]) accompanied by reduced near visual function (near visual acuity worse than 20/40 or stereoacuity worse than 240 seconds of arc).

PURPOSE

To compare attention, visual motor, and visual perceptual skills in uncorrected hyperopes and emmetropes attending preschool or kindergarten and evaluate their associations with visual function.

METHODS

Participants were 4 and 5 years of age with either hyperopia (≥3 to ≤6 D, astigmatism ≤1.5 D, anisometropia ≤1 D) or emmetropia (hyperopia ≤1 D; astigmatism, anisometropia, and myopia each <1 D), without amblyopia or strabismus. Examiners masked to refractive status administered tests of attention (sustained, receptive, and expressive), VMI, and VP. Binocular visual acuity, stereoacuity, and accommodative accuracy were also assessed at near. Analyses were adjusted for age, sex, race/ethnicity, and parent's/caregiver's education.

RESULTS

Two hundred forty-four hyperopes (mean, +3.8 ± [SD] 0.8 D) and 248 emmetropes (+0.5 ± 0.5 D) completed testing. Mean sustained attention score was worse in hyperopes compared with emmetropes (mean difference, -4.1; P < .001 for 3 to 6 D). Mean Receptive Attention score was worse in 4 to 6 D hyperopes compared with emmetropes (by -2.6, P = .01). Hyperopes with reduced near visual acuity (20/40 or worse) had worse scores than emmetropes (-6.4, P < .001 for sustained attention; -3.0, P = .004 for Receptive Attention; -0.7, P = .006 for VMI; -1.3, P = .008 for VP). Hyperopes with stereoacuity of 240 seconds of arc or worse scored significantly worse than emmetropes (-6.7, P < .001 for sustained attention; -3.4, P = .03 for Expressive Attention; -2.2, P = .03 for Receptive Attention; -0.7, P = .01 for VMI; -1.7, P < .001 for VP). Overall, hyperopes with better near visual function generally performed similarly to emmetropes.

CONCLUSIONS

Moderately hyperopic children were found to have deficits in measures of attention. Hyperopic children with reduced near visual function also had lower scores on VMI and VP than emmetropic children.

Visual Function of Moderately Hyperopic 4- and 5-Year-Old Children in the Vision in Preschoolers - Hyperopia in Preschoolers Study

PURPOSE

To compare visual performance between emmetropic and uncorrected moderately hyperopic preschool-age children without strabismus or amblyopia.

DESIGN

Cross-sectional study.

METHODS

setting: Multicenter, institutional. patient or study population: Children aged 4 or 5 years. intervention or observation procedures: Visual functions were classified as normal or reduced for each child based on the 95% confidence interval for emmetropic individuals. Hyperopic (≥3.0 diopters [D] to ≤6.0 D in the most hyperopic meridian; astigmatism ≤1.50 D; anisometropia ≤1.0 D) and emmetropic status were determined by cycloplegic autorefraction.

MAIN OUTCOME MEASURES

Uncorrected monocular distance and binocular near visual acuity (VA); accommodative response; and near random dot stereoacuity.

RESULTS

Mean (± standard deviation) logMAR distance visual acuity (VA) among 248 emmetropic children was better than among 244 hyperopic children for the better (0.05 ± 0.10 vs 0.14 ± 0.11, P < .001) and worse eyes (0.10 ± 0.11 vs 0.19 ± 0.10, P < .001). Mean binocular logMAR near VA was better in emmetropic than in hyperopic children (0.13 ± 0.11 vs 0.21 ± 0.11, P < .001). Mean accommodative response for emmetropic children was lower than for hyperopic subjects for both Monocular Estimation Method (1.03 ± 0.51 D vs 2.03 ± 1.03 D, P < .001) and Grand Seiko (0.46 ± 0.45 D vs 0.99 ± 1.0 D, P < .001). Median near stereoacuity was better in emmetropic than in than hyperopic children (40 sec arc vs 120 sec arc, P < .001). The average number of reduced visual functions was lower in emmetropic than in hyperopic children (0.19 vs 1.0, P < .001).

CONCLUSIONS

VA, accommodative response, and stereoacuity were significantly reduced in moderate uncorrected hyperopic preschool children compared to emmetropic subjects. Those with higher hyperopia (≥4 D to ≤6 D) were at greatest risk, although more than half of children with lower magnitudes (≥3 D to <4 D) demonstrated 1 or more reductions in function.

Uncorrected Hyperopia and Preschool Early Literacy: Results of the Vision in Preschoolers-Hyperopia in Preschoolers (VIP-HIP) Study

PURPOSE

To compare early literacy of 4- and 5-year-old uncorrected hyperopic children with that of emmetropic children.

DESIGN

Cross-sectional.

PARTICIPANTS

Children attending preschool or kindergarten who had not previously worn refractive correction.

METHODS

Cycloplegic refraction was used to identify hyperopia (≥3.0 to ≤6.0 diopters [D] in most hyperopic meridian of at least 1 eye, astigmatism ≤1.5 D, anisometropia ≤1.0 D) or emmetropia (hyperopia ≤1.0 D; astigmatism, anisometropia, and myopia <1.0 D). Threshold visual acuity (VA) and cover testing ruled out amblyopia or strabismus. Accommodative response, binocular near VA, and near stereoacuity were measured.

MAIN OUTCOME MEASURES

Trained examiners administered the Test of Preschool Early Literacy (TOPEL), composed of Print Knowledge, Definitional Vocabulary, and Phonological Awareness subtests.

RESULTS

A total of 492 children (244 hyperopes and 248 emmetropes) participated (mean age, 58 months; mean ± standard deviation of the most hyperopic meridian, +3.78±0.81 D in hyperopes and +0.51±0.48 D in emmetropes). After adjustment for age, race/ethnicity, and parent/caregiver's education, the mean difference between hyperopes and emmetropes was -4.3 (P = 0.01) for TOPEL overall, -2.4 (P = 0.007) for Print Knowledge, -1.6 (P = 0.07) for Definitional Vocabulary, and -0.3 (P = 0.39) for Phonological Awareness. Greater deficits in TOPEL scores were observed in hyperopic children with ≥4.0 D than in emmetropes (-6.8, P = 0.01 for total score; -4.0, P = 0.003 for Print Knowledge). The largest deficits in TOPEL scores were observed in hyperopic children with binocular near VA of 20/40 or worse (-8.5, P = 0.002 for total score; -4.5, P = 0.001 for Print Knowledge; -3.1, P = 0.04 for Definitional Vocabulary) or near stereoacuity of 240 seconds of arc or worse (-8.6, P < 0.001 for total score; -5.3, P < 0.001 for Print Knowledge) compared with emmetropic children.

CONCLUSIONS

Uncorrected hyperopia ≥4.0 D or hyperopia ≥3.0 to ≤6.0 D associated with reduced binocular near VA (20/40 or worse) or reduced near stereoacuity (240 seconds of arc or worse) in 4- and 5-year-old children enrolled in preschool or kindergarten is associated with significantly worse performance on a test of early literacy.

Six Year Refractive Change among White Children and Young Adults: Evidence for Significant Increase in Myopia among White UK Children

Objective

To determine six-year spherical refractive error change among white children and young adults in the UK and evaluate differences in refractive profiles between contemporary Australian children and historical UK data.

Design

Population-based prospective study.

Participants

The Northern Ireland Childhood Errors of Refraction (NICER) study Phase 1 examined 1068 children in two cohorts aged 6–7 years and 12–13 years. Prospective data for six-year follow-up (Phase 3) are available for 212 12–13 year olds and 226 18–20 year olds in each cohort respectively.

Methods

Cycloplegic refractive error was determined using binocular open-field autorefraction (Shin-Nippon NVision-K 5001, cyclopentolate 1%). Participants were defined by spherical equivalent refraction (SER) as myopic SER ≤-0.50D, emmetropic -0.50D<SER<+2.00 or hyperopic SER≥+2.00D.

Main Outcome Measures

Proportion and incidence of myopia.

Results

The proportion of myopes significantly increased between 6–7 years (1.9%) and 12–13 years (14.6%) (p<0.001) but not between 12–13 and 18–20 years (16.4% to 18.6%, p = 0.51). The estimated annual incidence of myopia was 2.2% and 0.7% for the younger and older cohorts respectively. There were significantly more myopic children in the UK at age 12–13 years in the NICER study (16.4%) than reported in Australia (4.4%) (p<0.001). However by 17 years the proportion of myopia neared equivalence in the two populations (NICER 18.6%, Australia 17.7%, p = 0.75). The proportion of myopic children aged 12–13 years in the present study (2006–2008) was 16.4%, significantly greater than that reported for children aged 10–16 years in the 1960’s (7.2%, p = 0.01). The proportion of hyperopes in the younger NICER cohort decreased significantly over the six year period (from 21.7% to 14.2%, p = 0.04). Hyperopes with SER ≥+3.50D in both NICER age cohorts demonstrated persistent hyperopia.

Conclusions

The incidence and proportion of myopia are relatively low in this contemporary white UK population in comparison to other worldwide studies. The proportion of myopes in the UK has more than doubled over the last 50 years in children aged between 10–16 years and children are becoming myopic at a younger age. Differences between the proportion of myopes in the UK and in Australia apparent at 12–13 years were eliminated by 17 years of age.

Subjective versus objective accommodative amplitude: preschool to presbyopia

PURPOSE

This study compared subjective and objective accommodative amplitudes to characterize changes from preschool to presbyopia.

METHODS

Monocular accommodative amplitude was measured with three techniques in random order (subjective push-up, objective minus lens stimulated, and objective proximal stimulated) on 236 subjects aged 3 to 64 years using a 1.5-mm letter. Subjective push-up amplitudes were the dioptric distance at which the target first blurred along a near-point rod. Objective minus lens stimulated amplitudes were the greatest accommodative response obtained by Grand Seiko autorefraction as subjects viewed the stimulus at 33 cm through increasing minus lens powers. Objective proximal stimulated amplitudes were the greatest accommodative response obtained by Grand Seiko autorefraction as subjects viewed the stimulus at increasing proximity from 40 cm up to 3.33 cm.

RESULTS

In comparison with subjective push-up amplitudes, objective amplitudes were lower at all ages, with the most dramatic difference occurring in the 3- to 5-year group (subjective push-up, 16.00 ± 4.98 diopters [D] vs. objective proximal stimulated, 7.94 ± 2.37 D, and objective lens stimulated, 6.20 ± 1.99 D). Objective proximal and lens stimulated amplitudes were largest in the 6- to 10-year group (8.81 ± 1.24 D and 8.05 ± 1.82 D, respectively) and gradually decreased until the fourth decade of life when a rapid decline to presbyopia occurred. There was a significant linear relationship between objective techniques (y = 0.74 + 0.96x, R2 = 0.85, p < 0.001) with greater amplitudes measured for the proximal stimulated technique (mean difference, 0.55 D).

CONCLUSIONS

Objective measurements of accommodation demonstrate that accommodative amplitude is substantially less than that measured by the subjective push-up technique, particularly in young children. These findings have important clinical implications for the management of uncorrected hyperopia.

Associations between hyperopia and other vision and refractive error characteristics

PURPOSE

To investigate the association of hyperopia greater than +3.25 diopters (D) with amblyopia, strabismus, anisometropia, astigmatism, and reduced stereoacuity in preschoolers.

METHODS

Three- to five-year-old Head Start preschoolers (N = 4040) underwent vision examination including monocular visual acuity (VA), cover testing, and cycloplegic refraction during the Vision in Preschoolers Study. Visual acuity was tested with habitual correction and was retested with full cycloplegic correction when VA was reduced below age norms in the presence of significant refractive error. Stereoacuity testing (Stereo Smile II) was performed on 2898 children during study years 2 and 3. Hyperopia was classified into three levels of severity (based on the most positive meridian on cycloplegic refraction): group 1: greater than or equal to +5.00 D, group 2: greater than +3.25 D to less than +5.00 D with interocular difference in spherical equivalent greater than or equal to 0.50 D, and group 3: greater than +3.25 D to less than +5.00 D with interocular difference in spherical equivalent less than 0.50 D. "Without" hyperopia was defined as refractive error of +3.25 D or less in the most positive meridian in both eyes. Standard definitions were applied for amblyopia, strabismus, anisometropia, and astigmatism.

RESULTS

Relative to children without hyperopia, children with hyperopia greater than +3.25 D (n = 472, groups 1, 2, and 3) had a higher proportion of amblyopia (34.5 vs. 2.8%, p < 0.0001) and strabismus (17.0 vs. 2.2%, p < 0.0001). More severe levels of hyperopia were associated with higher proportions of amblyopia (51.5% in group 1 vs. 13.2% in group 3) and strabismus (32.9% in group 1 vs. 8.4% in group 3; trend p < 0.0001 for both). The presence of hyperopia greater than +3.25 D was also associated with a higher proportion of anisometropia (26.9 vs. 5.1%, p < 0.0001) and astigmatism (29.4 vs. 10.3%, p < 0.0001). Median stereoacuity of nonstrabismic, nonamblyopic children with hyperopia (n = 206) (120 arcsec) was worse than that of children without hyperopia (60 arcsec) (p < 0.0001), and more severe levels of hyperopia were associated with worse stereoacuity (480 arcsec for group 1 and 120 arcsec for groups 2 and 3, p < 0.0001).

CONCLUSIONS

The presence and magnitude of hyperopia among preschoolers were associated with higher proportions of amblyopia, strabismus, anisometropia, and astigmatism and with worse stereoacuity even among nonstrabismic, nonamblyopic children.

Accommodation and vergence response gains to different near cues characterize specific esotropias

AIM

To describe preliminary findings of how the profile of the use of blur, disparity, and proximal cues varies between non-strabismic groups and those with different types of esotropia.

DESIGN

This was a case control study.

METHODOLOGY

A remote haploscopic photorefractor measured simultaneous convergence and accommodation to a range of targets containing all combinations of binocular disparity, blur, and proximal (looming) cues. Thirteen constant esotropes, 16 fully accommodative esotropes, and 8 convergence excess esotropes were compared with age- and refractive error-matched controls and 27 young adult emmetropic controls. All wore full refractive correction if not emmetropic. Response AC/A and CA/C ratios were also assessed.

RESULTS

Cue use differed between the groups. Even esotropes with constant suppression and no binocular vision (BV) responded to disparity in cues. The constant esotropes with weak BV showed trends for more stable responses and better vergence and accommodation than those without any BV. The accommodative esotropes made less use of disparity cues to drive accommodation (p = 0.04) and more use of blur to drive vergence (p = 0.008) than controls. All esotropic groups failed to show the strong bias for better responses to disparity cues found in the controls, with convergence excess esotropes favoring blur cues. AC/A and CA/C ratios existed in an inverse relationship in the different groups. Accommodative lag of > 1.0 D at 33 cm was common (46%) in the pooled esotropia groups compared with 11% in typical children (p = 0.05).

CONCLUSION

Esotropic children use near cues differently from matched non-esotropic children in ways characteristic to their deviations. Relatively higher weighting for blur cues was found in accommodative esotropia compared to matched controls.

Why do only some hyperopes become strabismic?

Children with hyperopia greater than +3.5 diopters (D) are at increased risk for developing refractive esotropia. However, only approximately 20% of these hyperopes develop strabismus. This review provides a systematic theoretical analysis of the accommodation and vergence oculomotor systems with a view to understanding factors that could either protect a hyperopic individual or precipitate a strabismus. The goal is to consider factors that may predict refractive esotropia in an individual and therefore help identify the subset of hyperopes who are at the highest risk for this strabismus, warranting the most consideration in a preventive effort.

Changes in ciliary muscle thickness during accommodation in children

PURPOSE

To investigate the morphology of the ciliary muscle during the act of accommodation in a population of children.

METHODS

Thirty children aged 6 to 12 years were enrolled. Accommodative response was measured through habitual correction. Height was measured as a control variable. Central axial length was measured with the IOLMaster. Four images of the temporal ciliary muscle were taken with the Visante Optical Coherence Tomographer at three different stimulus levels (0, 4, and 6 D) while accommodative response was monitored concurrently with the PowerRefractor. Accommodative response monitoring was time-matched to ciliary muscle image capture, and the mean was calculated for 5 s surrounding this time point. Four cycloplegic images of the temporal ciliary muscle were also taken. Ciliary muscle thickness measurements were made at the point of maximum thickness (CMTMAX) and at 1 mm (CMT1), 2 mm (CMT2) and 3 mm (CMT3) posterior to the sclera spur.

RESULTS

Increasing accommodative response was correlated with increases in the thickness of CMTMAX (p = <0.001) and CMT1 (p = <0.001) and decreases in the thickness of CMT3 (p = <0.001). Thicker values of CMTMAX under cycloplegic conditions were significantly correlated with values of CMTMAX (p = <0.001) and CMT1 (p = 0.001) while accommodating and approached significance in modeling CMT3 (p = 0.06). Mean axial length was correlated with the amount of thinning at CMT3 with accommodation (p = 0.002). Axial length was not significantly correlated with thickness values at CMTMAX (p = 0.7) or CMT1 (p = 0.6).

CONCLUSIONS

In a manner similar to previous adult studies, ciliary muscle thickness at CMTMAX and CMT1 increased with accommodation and CMT3 thinned with accommodation. Further investigation is necessary to determine whether CMT2 is a "fulcrum" point along the length of the ciliary muscle where the net change with accommodation is always zero or whether that point varies across subjects or with varying levels of accommodative effort.