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J.P. Kelly, A. Weiss; Development of Acuity in Infants With Motor vs Visual–Sensory Associated Nystagmus . Invest. Ophthalmol. Vis. Sci. 2005;46(13):2939.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Determine if there is differential post–natal development of acuity in patients with primary motor nystagmus versus patients with nystagmus associated with visual–sensory disturbances. Methods: The study included 66 infants, 23 with primary motor nystagmus, 15 with albinism, 9 with aniridia, and 19 with mild to moderate bilateral optic nerve hypoplasia (BONH). Motor nystagmus was confirmed by a normal fundus examination and full–field electroretinogram. Acuity was measured by Teller Acuity Cards (TAC) in patients younger than 3 years of age, and with Allen and Snellen optotypes in older patients. TAC cards were tested in both vertical and horizontal orientations and the best performance recorded from either the monocular or binocular test. Longitudinal data were obtained in 51 of these patients. To quantify age–related refinements, acuity for each group was binned into equal sample sizes. Two patients initially had had no tracking to the LV card (both < 4 months age) and were given an acuity of 0.1 cy/deg. Results: Average acuity for all groups was at or below the lower 95% limits of published norms and paralleled the normative curve up to 3 years of age. Although reduced average acuity remained within one octave of the lower limits. The slope of acuity development (in cy/deg per year) between the initial visit to 1 year of age was 1.3+/–0.2 for norms, 1.2 +/– 0.2 for primary motor nystagmus, 1.2 +/–0.3 for albinism, 0.7 +/–0.3 for aniridia, and 0.7 +/–0.3 for BONH. By comparison, visual acuities at 3 years of age (in Snellen equivalent) were 20/43, 20/52, 20/111, 20/92, 20/85, respectively. Conclusions: Post–natal visual development in patients with primary motor or visual–sensory associated nystagmus parallels the normative curve up to 1 year of age. Therefore, early post–natal visual development is limited more by visual immaturity than instability of gaze–holding or the associated visual sensory disorder. Neither nystagmus nor the visual–sensory disorder appears to limit acuity development until 1–3 years of age when refinements at higher spatial frequencies begin to emerge.
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