Characteristics and prognosis of visual field of G11778A mutation Leber hereditary optic neuropathy / 中华眼底病杂志

ABSTRACT

Objective:To analyze the characteristics and prognosis of visual field of Leber hereditary optic neuropathy (LHON) with G11778A mutation.Methods:A retrospective clinical study. Twenty-two (44 eyes) of LHON patients diagnosed with G11778A site mutation by mt-DNA examination from May 2008 to February 2018 in Ophthalmology Department of Dongfang Hospital of Beijing University of Chinese Medicine, were enrolled in this study. All patients underwent best corrected visual acuity (BCVA), visual field and optical coherence tomography (OCT). The BCVA examination was performed using the international standard visual acuity chart, which was converted into logarithm of the minimum angle of resolution (logMAR) BCVA for record. The thickness of the retinal nerve fiber layer (RNFL) in the 200μm×200μm annular region 1.73 mm outside the optic disc was measured by OCT. At least 7 visual field examinations were performed within one month before and after 2, 4, 8, 12, 18, 24 and 30 months of the course of disease by using Octopus 101 perimetry. Among 44 eyes, 27 eyes were detected with G2 procedure (G2 group) and 17 eyes were detected with LVC procedure (LVC group). The mean field defect (MD) and mean optical sensitivity (MS) were used as the main outcome indexes. According to the onset age, the patients were further divided into the ≤14 years old group and>14 years old group. There was a significant difference in initial logMAR BCVA between the G2 group and LVC group ( t=4.994, P=0.000), but there was no significant difference in gender ( χ2=1.896, P=0.169) and age ( t=0.337, P=0.708) between the two groups. Independent sample t test was used for comparison between groups, paired t test was used for comparison within groups, and one-way analysis of variance was used for comparison between groups. The statistical data were compared by χ2 test. Results:In the G2 group, the MD value of the subgroup of children (≤14 years old) decreased gradually during the follow-up period, and the MD value since 18 months after onset was significantly lower than the value of 2 months after onset ( t=3.813, 4.590, 5.033; P=0.002, 0.001, 0.000). No obvious visual field index changes were seen in other subgroups ( P>0.05). The central scotoma was the most common type of visual field defect in the early stage, and the diffuse defect was the most common type of visual field defect in the late stage. There was a significant difference in the types of visual field distribution between the early and late stage in G2 group ( χ2=17.414, P=0.015). There was no significant difference in the type of visual field distribution between the early and late stage in LVC group ( χ2=4.541, P=0.474). The MD value in the G2 group remained stable within 8 months after onset, but significantly improved after 18 months after onset ( t=2.100, 3.217, 3.566; P=0.046, 0.003, 0.001). The MS in the LVC group did not significantly improve during follow-up ( P>0.05). The average visual acuity of the G2 group was significantly improved from 12 months ( t=3.039, 3.678, 4.264, 5.078; P=0.008, 0.002, 0.001, 0.000). The visual acuity of the eyes in the G2 group was better than that of the LVC group during all follow-up periods ( P≤0.05). The RNFL thickness of all patients continued to decrease after onset, but the RNFL thickness was significantly higher at 4, 8, 18, 24, 30 months in the G2 group than those in the LVC group ( t=2.471, 2.269, 2.474, 2.509, 2.782; P=0.018, 0.028, 0.017, 0.016, 0.008). Conclusions:The main types of visual field defect of LHON with G11778A mutation are the central scotoma in the early stage, while the diffuse defect and central scotoma are both very common in the later stage. The visual field of LHON patients examined by G2 procedure is significantly improved during the follow-up, as well as the visual acuity improved significantly, and the visual field improvement in younger cases (≤14 years old) is better than that of older cases (>14 years old), but the visual field of the LVC procedure cases did not improve during follow-up.