Amy L. Davis

Measurement of Refractive Error in Native American Preschoolers: Validity and Reproducibility of Autorefraction

Purpose To examine (1) reproducibility of cycloplegic retinoscopy (C-RNS), cycloplegic autorefraction (C-Autoref), and noncycloplegic autorefraction (NC-Autoref), and (2) validity of C-Autoref and NC-Autoref compared with C-RNS in preschoolers with astigmatism. Methods Subjects were 36 Native American preschoolers. Three measurements of right eye refractive error were obtained with each of three methods: C-RNS (by three different retinoscopists), C-Autoref, and NC-Autoref (Nikon Retinomax K+). Vector methods (vector dioptric distance, VDD) were used in the analyses. Results Mean reproducibility was 0.41 D (SD = 0.18) for C-RNS, 0.25 D (SD = 0.17) for C-Autoref, and 0.37 D (SD = 0.21) for NC-Autoref. Mean agreement between C-Autoref and C-RNS ranged from 0.51 to 0.61 VDD (SD = 0.24 to 0.35), and ranged from 1.66 to 1.74 VDD (SD = 1.11 to 1.25) for agreement between NC-Autoref and C-RNS. Mean bias was −0.07 +0.21 × 149 and −1.33 +0.34 × 178 for C-Autoref and NC-Autoref, respectively. Conclusions C-Autoref provided reliable and valid measurements of refractive error in young children. NC-Autoref measurements were reliable within subjects, but there was large variability in validity among subjects.

Accommodation in Astigmatic Children During Visual Task Performance

PURPOSE To determine the accuracy and stability of accommodation in uncorrected children during visual task performance. METHODS Subjects were second- to seventh-grade children from a highly astigmatic population. Measurements of noncycloplegic right eye spherical equivalent (Mnc) were obtained while uncorrected subjects performed three visual tasks at near (40 cm) and distance (2 m). Tasks included reading sentences with stimulus letter size near acuity threshold and an age-appropriate letter size (high task demands) and viewing a video (low task demand). Repeated measures ANOVA assessed the influence of astigmatism, task demand, and accommodative demand on accuracy (mean Mnc) and variability (mean SD of Mnc) of accommodation. RESULTS For near and distance analyses, respectively, sample size was 321 and 247, mean age was 10.37 (SD 1.77) and 10.30 (SD 1.74) years, mean cycloplegic M was 0.48 (SD 1.10) and 0.79 diopters (D) (SD 1.00), and mean astigmatism was 0.99 (SD 1.15) and 0.75 D (SD 0.96). Poor accommodative accuracy was associated with high astigmatism, low task demand (video viewing), and high accommodative demand. The negative effect of accommodative demand on accuracy increased with increasing astigmatism, with the poorest accommodative accuracy observed in high astigmats (≥3.00 D) with high accommodative demand/high hyperopia (1.53 D and 2.05 D of underaccommodation for near and distant stimuli, respectively). Accommodative variability was greatest in high astigmats and was uniformly high across task condition. No/low and moderate astigmats showed higher variability for the video task than the reading tasks. CONCLUSIONS Accuracy of accommodation is reduced in uncorrected children with high astigmatism and high accommodative demand/high hyperopia, but improves with increased visual task demand (reading). High astigmats showed the greatest variability in accommodation.

Convergence Insufficiency, Accommodative Insufficiency, Visual Symptoms, and Astigmatism in Tohono O’odham Students

Purpose. To determine rate of convergence insufficiency (CI) and accommodative insufficiency (AI) and assess the relation between CI, AI, visual symptoms, and astigmatism in school-age children. Methods. 3rd–8th-grade students completed the Convergence Insufficiency Symptom Survey (CISS) and binocular vision testing with correction if prescribed. Students were categorized by astigmatism magnitude (no/low: <1.00 D, moderate: 1.00 D to <3.00 D, and high: ≥3.00 D), presence/absence of clinical signs of CI and AI, and presence of symptoms. Analyses determine rate of clinical CI and AI and symptomatic CI and AI and assessed the relation between CI, AI, visual symptoms, and astigmatism. Results. In the sample of 484 students (11.67 ± 1.81 years of age), rate of symptomatic CI was 6.2% and symptomatic AI 18.2%. AI was more common in students with CI than without CI. Students with AI only (p = 0.02) and with CI and AI (p = 0.001) had higher symptom scores than students with neither CI nor AI. Moderate and high astigmats were not at increased risk for CI or AI. Conclusions. With-the-rule astigmats are not at increased risk for CI or AI. High comorbidity rates of CI and AI and higher symptoms scores with AI suggest that research is needed to determine symptomatology specific to CI.

Reading Fluency in School-Aged Children with Bilateral Astigmatism.

Purpose To compare oral reading fluency (ORF) in students with no/low astigmatism and moderate/high astigmatism and to assess the impact of spectacle correction on ORF in moderate and high astigmats. Methods Subjects were third- to eighth-grade students from a highly astigmatic population. Refractive error was determined through subjectively refined cycloplegic autorefraction. Data from students with ocular abnormalities, anisometropia, symptomatic binocular vision disorders, or refractive error that did not meet study criteria (no/low [cylinder < 1.00 both eyes, no significant myopia/hyperopia], moderate [cylinder ≥ 1.00 D both eyes, mean ≥ 1.00 D and < 3.00 D], or high astigmatism group [cylinder ≥ 1.00 D both eyes, mean ≥ 3.00 D]) were excluded. Oral reading fluency was tested with a modified version of the Dynamic Indicators of Basic Early Literacy Skills (DIBELS) Next test of ORF. No/low astigmats were tested without spectacles; astigmats were tested with and without spectacles. Mean ORF was compared in no/low astigmats and astigmats (with and without correction). Improvement in ORF with spectacles was compared between moderate and high astigmats. Results The sample included 130 no/low, 67 moderate, and 76 high astigmats. ORF was lower in uncorrected astigmats than in no/low astigmats (p = 0.011). ORF did not significantly differ in no/low astigmats and corrected astigmats (p = 0.10). ORF significantly improved with spectacle correction in high astigmats (p = 0.001; mean improvement, 6.55 words per minute) but not in moderate astigmats (p = 0.193; mean improvement, 1.87 words per minute). Effects of spectacle wear were observed in students who read smaller text stimuli (older grades). Conclusions ORF is significantly reduced in students with bilateral astigmatism (≥1.00D) when uncorrected but not when best-corrected compared with their nonastigmatic peers. Improvement in ORF with spectacle correction is seen in high astigmats but not in moderate astigmats. These data support the recommendation for full-time spectacle wear in astigmatic students, particularly those with high astigmatism.

Visual Motor and Perceptual Task Performance in Astigmatic Students

Purpose. To determine if spectacle corrected and uncorrected astigmats show reduced performance on visual motor and perceptual tasks. Methods. Third through 8th grade students were assigned to the low refractive error control group (astigmatism < 1.00 D, myopia < 0.75 D, hyperopia < 2.50 D, and anisometropia < 1.50 D) or bilateral astigmatism group (right and left eye ≥ 1.00 D) based on cycloplegic refraction. Students completed the Beery-Buktenica Developmental Test of Visual Motor Integration (VMI) and Visual Perception (VMIp). Astigmats were randomly assigned to testing with/without correction and control group was tested uncorrected. Analyses compared VMI and VMIp scores for corrected and uncorrected astigmats to the control group. Results. The sample included 333 students (control group 170, astigmats tested with correction 75, and astigmats tested uncorrected 88). Mean VMI score in corrected astigmats did not differ from the control group (p = 0.829). Uncorrected astigmats had lower VMI scores than the control group (p = 0.038) and corrected astigmats (p = 0.007). Mean VMIp scores for uncorrected (p = 0.209) and corrected astigmats (p = 0.124) did not differ from the control group. Uncorrected astigmats had lower mean scores than the corrected astigmats (p = 0.003). Conclusions. Uncorrected astigmatism influences visual motor and perceptual task performance. Previously spectacle treated astigmats do not show developmental deficits on visual motor or perceptual tasks when tested with correction.

A preliminary study of astigmatism and early childhood development

PURPOSE To determine whether uncorrected astigmatism in toddlers is associated with poorer performance on the Bayley Scales of Infant and Toddler Development, 3rd edition (BSITD-III). METHODS Subjects were 12- to 35-month-olds who failed an instrument-based vision screening at a well-child check. A cycloplegic eye examination was conducted. Full-term children with no known medical or developmental conditions were invited to participate in a BSITD-III assessment conducted by an examiner masked to the childs eye examination results. Independent samples t tests were used to compare Cognitive, Language (Receptive and Expressive), and Motor (Fine and Gross) scores for children with moderate/high astigmatism (>2.00 D) versus children with no/low refractive error (ie, children who had a false-positive vision screening). RESULTS The sample included 13 children in each group. The groups did not differ on sex or mean age. Children with moderate/high astigmatism had significantly poorer mean scores on the Cognitive and Language scales and the Receptive Communication Language subscale compared to children with no/low refractive error. Children with moderate/high astigmatism had poorer mean scores on the Motor scale, Fine and Gross Motor subscales, and the Expressive Communication subscale, but these differences were not statistically significant. CONCLUSIONS The results suggest that uncorrected astigmatism in toddlers may be associated with poorer performance on cognitive and language tasks. Further studies assessing the effects of uncorrected refractive error on developmental task performance and of spectacle correction of refractive error in toddlers on developmental outcomes are needed to support the development of evidence-based spectacle prescribing guidelines.

Interrater and test-retest reliability of the beery visual-motor integration in schoolchildren

PURPOSE To assess interrater and test-retest reliability of the 6th Edition Beery-Buktenica Developmental Test of Visual-Motor Integration (VMI) and test-retest reliability of the VMI Visual Perception Supplemental Test (VMIp) in school-age children. METHODS Subjects were 163 Native American third- to eighth-grade students with no significant refractive error (astigmatism <1.00 D, myopia <0.75 D, hyperopia <2.50 D, anisometropia <1.50 D) or ocular abnormalities. The VMI and VMIp were administered twice, on separate days. All VMI tests were scored by two trained scorers, and a subset of 50 tests was also scored by an experienced scorer. Scorers strictly applied objective scoring criteria. Analyses included interrater and test-retest assessments of bias, 95% limits of agreement, and intraclass correlation analysis. RESULTS Trained scorers had no significant scoring bias compared with the experienced scorer. One of the two trained scorers tended to provide higher scores than the other (mean difference in standardized scores = 1.54). Interrater correlations were strong (0.75 to 0.88). VMI and VMIp test-retest comparisons indicated no significant bias (subjects did not tend to score better on retest). Test-retest correlations were moderate (0.54 to 0.58). The 95% limits of agreement for the VMI were -24.14 to 24.67 (scorer 1) and -26.06 to 26.58 (scorer 2), and the 95% limits of agreement for the VMIp were -27.11 to 27.34. CONCLUSIONS The 95% limit of agreement for test-retest differences will be useful for determining if the VMI and VMIp have sufficient sensitivity for detecting change with treatment in both clinical and research settings. Further research on test-retest reliability reporting 95% limits of agreement for children across different age ranges is recommended, particularly if the test is to be used to detect changes due to intervention or treatment.

Assessment of grating acuity in infants and toddlers using an electronic acuity card: The Dobson Card

PURPOSE To determine if testing binocular visual acuity in infants and toddlers using the Acuity Card Procedure (ACP) with electronic grating stimuli yields clinically useful data. METHODS Participants were infants and toddlers ages 5 to 36.7 months referred by pediatricians due to failed automated vision screening. The ACP was used to test binocular grating acuity. Stimuli were presented on the Dobson Card. The Dobson Card consists of a handheld matte-black plexiglass frame with two flush-mounted tablet computers and is similar in size and form to commercially available printed grating acuity testing stimuli (Teller Acuity Cards II [TACII]; Stereo Optical, Inc., Chicago, IL). On each trial, one tablet displayed a square-wave grating and the other displayed a luminance-matched uniform gray patch. Stimuli were roughly equivalent to the stimuli available in the printed TACII stimuli. After acuity testing, each child received a cycloplegic eye examination. Based on cycloplegic retinoscopy, patients were categorized as having high or low refractive error per American Association for Pediatric Ophthalmology and Strabismus vision screening referral criteria. Mean acuities for high and low refractive error groups were compared using analysis of covariance, controlling for age. RESULTS Mean visual acuity was significantly poorer in children with high refractive error than in those with low refractive error (P = .015). CONCLUSIONS Electronic stimuli presented using the ACP can yield clinically useful measurements of grating acuity in infants and toddlers. Further research is needed to determine the optimal conditions and procedures for obtaining accurate and clinically useful automated measurements of visual acuity in infants and toddlers.