Nancy Carlson

A Survey of Clinical Prescribing Philosophies for Hyperopia

Background. Prescribing philosophies for hyperopic refractive error in symptom-free children vary widely because relatively little information is available regarding the natural history of hyperopic refractive error in children and because accommodation and binocular function closely related to hyperopic refractive error vary widely among children. We surveyed pediatric optometrists and ophthalmologists to evaluate typical prescribing philosophies for hyperopia. Methods. Practitioners were selected from the American Academy of Optometry Binocular Vision, Perception, and Pediatric Optometry Section; the College of Vision Development; the pediatric and binocular vision faculty members of the colleges of optometry; and the American Association for Pediatric Ophthalmology and Strabismus. Surveys were mailed to 314 participants: 212 optometrists and 102 ophthalmologists. Results. A total of 161 (75%) of the optometrists and 59 (57%) of the ophthalmologists responded. About one-third of optometrists surveyed prescribe optical correction for symptom-free 6-month-old infants with +3.00 D to +4.00 D hyperopia, but fewer than 5% of ophthalmologists prescribe at this level. Most eye care practitioners prescribe optical correction for symptom-free 2-year-old children with +5.00 D of hyperopia, and this criterion for hyperopia decreases with age. Most ophthalmologists (71.4%) prescribe the full amount of astigmatism and less than the full amount of cycloplegic spherical component, and most optometrists (71.6%) prescribe less than the full amount of both components. When prescribing less than the full amount of astigmatism, eye care practitioners do not tend to prescribe a specific proportion of the cycloplegic refractive error. Conclusion. Pediatric eye care providers show a lack of consensus on prescribing philosophies for hyperopic children.

Contrast sensitivity norms for the mentor B-VAT II-SG video acuity tester

The Mentor B-VAT II-SG video acuity tester is a high-resolution video system designed to present many of the targets used in standard vision examinations (Snellen optotypes, clock charts, etc.). The SG model also presents sinusoidal gratings at various spatial frequencies and contrasts, making it possible to measure contrast sensitivity functions (CSFs). Using this system, we measured CSFs in a group of 69 young observers with well corrected vision. Contrast sensitivity scores were obtained at each of five spatial frequencies. A total of 5710 trials was presented. The mean contrast sensitivity scores of our group agree well with norms of other available CSF measurement systems, provided that the low spatial frequency truncation effects of each system are taken into account. A random subset of the group was retested 1 month later; no significant differences were found, demonstrating the reliability of the measurements. The data of this study should aid the clinician in identifying visual disorders. The data may be used to determine quantitative deviations from the norms or as a rapid screening test.