BackgroundInfantile nystagmus (IN) is an oculomotor disorder that is characterized by conjugate involuntary, rapid and repetitive movement of the eyes. To date, the pathogenesis of IN remains unclear. Many patients show an X-linked inheritance pattern. In this study, we explored the mutation in the FERM domain-containing 7 (FRMD7) gene in a Chinese family with X-linked infantile nystagmus.MethodsWe conducted comprehensive ocular examinations and collected 5 ml of blood samples from members of a family with X-linked IN and 100 normal controls. Mutations in FRMD7 were identified by sequencing PCR products.ResultsWe found a 7-bp deletion(c.823-829delACCCTAC) in the 9th exon of FRMD7 in a Chinese family with IN, which predicted a truncation of the protein.ConclusionsThis study reported a novel mutation of the FRMD7 gene occurred in a Chinese family with IN, thus expanding the spectrum of FRMD7 mutations causing IN, and further confirming that the mutations of FRMD7 are the underlying molecular cause of IN.

Clinical RelevanceA vergence formula may provide a simple and reliable calculation of the refractive status of aphakic eyes.BackgroundMeasuring the refractive error of pediatric eyes with aphakia is difficult. This study investigated the accuracy and applicability of a vergence formula for estimating the refractive status of such eyes.MethodsA retrospective review of the medical records, created between January 2016 and December 2018, of pediatric patients with aphakia was conducted. A vergence formula, based on axial length, was used to calculate the refractive status of the aphakic eyes. The refractive values determined using retinoscopy, an automatic refractometer, and the vergence formula were compared.ResultsA total of 72 eyes (47 patients) were analyzed. The spherical equivalents of the refractive errors (mean ± standard deviation) of the eyes were determined using retinoscopy (13.01 ± 3.27 D), automatic refractometry (12.90 ± 3.23 D), and the vergence formula (12.70 ± 3.4 D). The correlation coefficient between retinoscopy values determined using retinoscopy and the vergence formula, automatic refractometry and the vergence formula, and retinoscopy and automatic refractometry were 0.968, 0.987, and 0.979, respectively. The Bland-Altman consistency analysis revealed that the mean differences in the spherical equivalent values between retinoscopy and automatic refractometry, retinoscopy and the vergence formula, and automatic refractometry and the vergence formula were 0.11 D, 0.31 D, and 0.21 D, respectively, with 95% limits of agreement of−1.20 to 1.41 D,−1.37 to 2.00 D, and−0.90 to 1.31 D, respectively.ConclusionThe vergence formula was effective for evaluating the refractive status of aphakic eyes in pediatric patients.