Mary Everett

Breast-Feeding and Optimal Visual Development

The goal of the present study was to determine whether dietary supply of omega-3 essential fatty acid (EFA) influences visual development in healthy pre-term and full-term infants. Visual status was examined in human milk-fed infants (ample dietary omega-3 EFA supply) and corn oil-based formula-fed infants (no dietary omega-3 EFA; standard formula prior to 1987). At 57 weeks postconception (4 months adjusted age), both pre-term and full-term human milk-fed infants had significantly better visual evoked potential (VEP) and forced-choice preferential-looking (FPL) acuity than formula-fed infants. Acuity was correlated with a dietary omega-3 sufficiency index from red blood cell membranes obtained at 57 weeks postconception. At 36 months, full-term human milk-fed children had significantly better random dot stereo acuity and letter matching ability than formula-fed children. Stereo acuity and performance on the letter matching test were correlated with a dietary omega-3 sufficiency index from red blood cell membranes obtained at 4 months. These results suggest that dietary omega-3 fatty acids play an important role in visual development.

Delayed consecutive exotropia following 7-millimeter bilateral medial rectus recession for congenital esotropia

The rate of delayed consecutive exotropia after bilateral 7-millimeter medial rectus recession for large angle congenital esotropia in 88 patients was 27% (24/88), larger than previously reported. The rate was 38% (8/21) in infants having surgery prior to 7 months of age, 20% (10/49) in infants undergoing surgery at 7 to 12 months of age, and 33% (6/18) in patients undergoing surgery at 13 months of age or later. The onset of consecutive exotropia averaged 26.8 months postoperatively, allowing a long period of good alignment for binocular vision to develop before exotropia surgery was required. Physicians and parents should be aware that delayed consecutive exotropia may develop several years postoperatively. Since delayed consecutive exotropia may be characteristic of the 7-millimeter recession procedure or characteristic of all patients who have had surgery for congenital esotropia, a prospective long-term study to compare the 7-millimeter procedure with the three- and four-muscle procedure would be helpful.

Random dot stereoacuity following surgical correction of infantile esotropia

Surgical correction of infantile esotropia prior to age 2 is associated with a higher prevalence of fusion and stereopsis than surgical correction after 2 years of age. The advantages and disadvantages of surgical intervention at the early or late end of this window have been debated in the literature. In the present study, random dot (RD) stereoacuity outcomes were evaluated in order to determine whether a binocular sensory benefit is associated with early or late surgery. Participants were 73 healthy children enrolled in a prospective study of visual development in infantile esotropia. All children had initial surgical correction at 5 to 16 months of age. RD stereoacuity was evaluated at approximately 5 years of age (59.7 +/- 14.9 months). Overall, 41.1% of children demonstrated RD stereopsis. The percentage of children demonstrating RD stereopsis was not significantly different among groups that were surgically corrected at 5 to 8 months (43.8%), 9 to 12 months (47.4%), and 13 to 16 months (31.8%). However, among those children who achieved RD stereopsis, the prevalence of foveal (< 60 sec) or macular (61 to 200 sec) stereoacuity was significantly higher among those who had surgery at 5 to 8 months (42.9%; Z = 2.06, p < 0.02) or 9 to 12 months (55.6%; Z = 2.38, p < 0.009) than among those who had surgery at 13 to 16 months (0.0%). Although surgical correction of infantile esotropia during the first year of life is not associated with a higher prevalence of RD stereopsis, it is associated with better RD stereoacuity among those children who achieve stereopsis following surgery.

Color Vision Screening of Young Children

Early detection of congenital color vision defects is desirable, but school screening studies have been stymied by lack of a suitable test. We evaluated a new color vision test, the APT-5, for use by volunteer screeners in schools and preschools. The screeners tested 1794 children, ages 3 to 13 years, and found the APT-5 easy to use with young children ages 5 years and up. Children who failed the screening were recruited for diagnostic color vision testing; for the children ages 5 to 13 years, 56% of those who failed the screening were successfully recruited. Data analysis indicated that the false-positive rate in this age group was 1% to 2%, and that for boys in this age group the positive predictive value was 71% to 81%. Retest data indicated that most false-positives were not due to the test itself, but to other factors in the school screening situation. Two thirds of all children scored as abnormal by anomaloscopy were simple deuteranomalous, indicating that the APT-5 effectively identified even mild color defects. The results of this trial indicate that the APT-5 is suitable for school color vision screening of children ages 5 years and up.

The importance of controlled illumination in color vision testing in a pediatric ophthalmology clinical practice.

The AO-HRR pseudoisochromatic plates are commonly used for color vision testing in pediatric ophthalmology; however, the recommended procedure for obtaining proper illumination (a completely darkened room and standard illuminant) is typically not followed. To evaluate the role of the illuminant in clinical testing with the AO-HRR, 132 children, ages 3 to 16 years, were tested with and without the recommended illuminant (MacBeth Easel Lamp) and with the self-illuminated APT-5 Color Vision Tester. Twenty-two failed the AO-HRR with the recommended illuminant; 28 failed the AO-HRR without the illuminant. Only 13 failed the APT-5. The Cochran Q test for three related samples showed that the differences among the three groups were significant (Q = 17.1, P < .001). Diagnostic evaluation following clinical screening indicated that the differences among the tests were primarily due to false alarms, which were greatest without the recommended illuminant and least with the APT-5. These results demonstrate the importance of controlled illumination in color vision testing, either by using the recommended illumination with the AO-HRR or a self-illuminated test such as the APT-5.