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

Abstract

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.

Ocular residual and corneal astigmatism in a clinical population of high school students

“…Another potential limitation might be the lack of a cycloplegic procedure for the KR-1W measurement. Although cycloplegia provides more repeatable inter-visit results, this is mostly applicable for spherical power, and has only a subtle effect on cylindrical power [ 41 – 43 ]. However, the design of the study was not intended to compare values between visits, but rather to decompose the TA for each reading.…”

Higher-order aberrations and best-corrected visual acuity in Native American children with a high prevalence of astigmatism

“…At least 7 images were required for averaging within each subject. 14 The total root-mean-square (RMS) was calculated as the root of the sum of squared Zernike coefficients after scaling each observation to a 4 mm diameter pupil and averaging the coefficients within subjects. We also combined the individual Zernike coefficients related to coma (z07s and z08s) into a single unsigned RMS coma.…”

Comparison of Refractive Measures of Three Autorefractors in Children and Adolescents

“… 7 – 9 Since the invention of automated refractors, such devices have been increasing in popularity in clinical practice, as well as in epidemiological research, particularly for large-scale vision screening in children. 10 – 13 Noncycloplegic autorefraction was shown to have a tendency toward minus overcorrection in school-age children resulting in overdiagnosis of myopia, 14 , 15 whereas cycloplegic autorefraction is potentially more sensitive than subjective refraction and was recommended to be a necessity for precise measurement of refractive errors, especially in hyperopic eyes and in pediatric cases. 16 – 18 …”