Abstract

Volume.124 Number.8

Original article : Clinical science

Investigation of Association between Macular Morphology and the Null Zone in Infantile Nystagmus Syndrome
Yoichi Okita, Akiko Kimura, Katsuhide Yamadera, Ayame Imai, Mana Okamoto, Fumi Gomi
Department of Ophthalmology, Hyogo College of Medicine

Purpose: To investigate an association between macular morphology and the null zone in infantile nystagmus syndrome (INS).
Subjects and methods: This study included a total of 34 patients with INS who visited the Department of Ophthalmology of the Hyogo College of Medicine Hospital with the chief complaint of ocular nystagmus in 6 years from 2013 (mean age 9.7 years: 5-15 years; mean follow-up period: 48 months: 8-91 months). Macular morphology was evaluated by optical coherence tomography (OCT) in terms of the presence or absence of foveal pits and the presence or absence of ellipsoid zone irregularity. Subjects with a normal central foveal structure were defined as the normal group, while other subjects fell into the hypoplasia group. Subjects were classified according to macular morphology and the presence or absence of a null zone. We then investigated visual acuity (logMAR), foveal macular thickness, astigmatism, stereopsis, and manifest strabismus in each group.
Results: There were 24 subjects in the normal group and 10 subjects in the hypoplasia group. In the normal group, a null zone was observed in 17/24 cases and was not in 7/24 cases. No patients in the hypoplasia group had a null zone. In the normal group, mean visual acuity was -0.028 for patients with a null zone and 0.181 for those without a null zone, while mean visual acuity was 0.476 in the hypoplasia group; the observed difference among the three groups was of significance (p<0.0001, one-way ANOVA). The rates of having astigmatism and strabismus as complications in the hypoplasia group were both significantly higher than the corresponding rates in the normal group (p<0.05).
Conclusions: Visual acuity prognosis was poor when macular hypoplasia was present, with no patients in the hypoplasia group exhibiting a null zone. Visual acuity outcome was relatively good for cases exhibiting central foveal structure on OCT even in cases of ocular nystagmus with no null zone.
Nippon Ganka Gakkai Zasshi (J Jpn Ophthalmol Soc) 124: 621-627, 2020.

Key words
Infantile nystagmus syndrome, Optical coherence tomography (OCT), Null zone, Foveal hypoplasia
Reprint requests to
Yoichi Okita, M. D. Department of Ophthalmology, Hyogo College of Medicine. 1-1 Mukogawa-cho, Nishinomiya-shi 663-8501, Japan