Background

Aniridia patients have poor visual acuity and iris malformation. The fovea in these patients is underdeveloped, but the relationship between structure and electrophysiologic function remains incompletely understood. This study correlates electrophysiology, visual acuity and optical coherence tomography (OCT) in patients with aniridia secondary to mutations in the PAX6 gene and compares with age-similar controls.

Methods

Patients were recruited from clinical practice. The mfERG protocol was a 4-min 103-hexagon protocol covering approximately 40° in diameter of central retina. Diagnosys full-field ERG (ffERG) and VERIS multifocal ERG (mfERG) were obtained using standard International Society for Clinical Electrophysiology of Vision protocols. OCT central thickness was recorded, and an OCT foveal score was calculated. Nonparametric permutation testing was utilized to determine the statistical significance.

Results

A total of 6 aniridia patients and 25 control patients were recruited. On mfERG, aniridia patients had significantly lower amplitudes in rings 1–3 (p = 0.0006, 0.0013, 0.0132), shorter latencies in ring 1 (p = 0.0312) and longer latencies in rings 5 and 6 (p = 0.0026, p = 0.0042) than controls. There was a significantly positive relationship in aniridia patients between logMAR visual acuity and mfERG amplitude in ring 4 (p = 0.0392) and ring 5 (p = 0.0489). On ffERG, there was no difference in amplitudes, though photopic 3.0 a- and b-wave latency, 30 Hz flicker latency and scotopic 0.01 b-wave latency were significantly longer in aniridia patients versus control (p = 0.0018, 0.0.0005, 1.00 x \(10^{{ - 4}}\), 0.0198). Thicker central macula on OCT correlated with lower mfERG amplitudes in rings 4–6 (p = 0.0369, 0.0292, 0.0255). There was no correlation between visual acuity and central macular thickness or foveal hypoplasia score as determined by OCT.

Conclusions

Higher amplitude on mfERG correlated with poorer visual acuity in rings 4 and 5 in patients with PAX6 mutations. The slope of the change in amplitude from central to peripheral rings on the mfERG is significantly different in aniridia patients compared to controls, with a slower drop-off of amplitude from center to periphery. Additionally, mfERG in aniridia showed lower amplitudes than controls in rings 1–3. These changes along with the lack of correlation between visual acuity and central macular thickness/OCT score suggest that changes in electrical topography may be important to visual deficits in patients with PAX6 gene mutations.

中文翻译：

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PAX6 突变导致无虹膜视网膜电图、中心凹解剖和视力的相关性

背景

无虹膜患者视力差，虹膜畸形。这些患者的中央凹发育不全，但结构与电生理功能之间的关系仍不完全清楚。本研究将继发于PAX6基因突变的无虹膜患者的电生理学、视力和光学相干断层扫描 (OCT) 相关联，并与年龄相似的对照组进行了比较。

方法

患者是从临床实践中招募的。mfERG 协议是一个 4 分钟的 103 六边形协议，覆盖中央视网膜直径约 40°。Diagnosys 全视野 ERG (ffERG) 和 VERIS 多焦 ERG (mfERG) 是使用标准的国际视觉临床电生理学会协议获得的。记录 OCT 中心厚度，并计算 OCT 中心凹评分。非参数置换检验用于确定统计显着性。

结果

共招募了 6 名无虹膜患者和 25 名对照患者。在 mfERG 上，无虹膜患者在第 1-3 环（p = 0.0006、0.0013、0.0132）中的振幅显着降低，在第 1 环中的潜伏期较短（p = 0.0312），在第 5 和第 6 环中的潜伏期较长（p = 0.0026，p = 0.0042 ) 比控制。在无虹膜症患者中，logMAR 视力与第 4 环 ( p = 0.0392) 和第 5 环 ( p = 0.0489) 中的 mfERG 振幅之间存在显着正相关。在 ffERG 上，幅度没有差异，尽管与对照组相比，无虹膜患者的明视 3.0 a 波和 b 波潜伏期、30 Hz 闪烁潜伏期和暗视 0.01 b 波潜伏期明显更长（p= 0.0018, 0.0.0005, 1.00 x \(10^{{ - 4}}\) , 0.0198)。OCT 上较厚的中央黄斑与第 4-6 环中较低的 mfERG 振幅相关（p = 0.0369、0.0292、0.0255）。OCT确定的视力与中央黄斑厚度或中心凹发育不全评分之间没有相关性。

结论

mfERG 的较高幅度与PAX6突变患者的第 4 环和第 5 环视力较差相关。无虹膜患者与对照组相比，mfERG 上从中心环到外围环的幅度变化斜率显着不同，从中心到外围的幅度下降较慢。此外，无虹膜中的 mfERG 显示出比环 1-3 中的对照更低的振幅。这些变化以及视力与中央黄斑厚度/OCT 评分之间缺乏相关性表明，电地形图的变化可能对PAX6基因突变患者的视力缺陷很重要。