Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India.
ASG Eye Hospital, Kolkata, West Bengal, India.
Eye (Lond). 2019 Oct;33(10):1547-1555. doi: 10.1038/s41433-019-0442-y. Epub 2019 Apr 24.
Although full-field electroretinogram (ffERG) is the gold standard test to detect physiological dysfunction in siderosis, it measures overall retinal function. This study aims to determine if multifocal electroretinogram (mfERG) can detect subclinical siderosis in eyes with an iron intraocular foreign body (IOFB).
Twenty eyes of 20 patients with retained iron IOFB, clear ocular media and good visual acuity (≥20/120) were enroled in this prospective case-control study. The fellow eyes served as control. These were evaluated with ffERG and mfERG at baseline. Serial mfERG was done till six months after pars plana vitrectomy with IOFB removal. Primary outcomes measures were amplitude and peak time of P1 and N1 wave of mfERG.
The median age was 25 years (range 18-55). Most patients (n = 14/20) presented within a month of trauma. Baseline ffERG showed no difference in either 'a' or 'b' wave amplitude or peak time between cases and controls. However, on mfERG, there was a significant decrease in P1 and N1 wave amplitude and delay in P1 wave peak time in <2° retinal ring in cases as compared to controls (p = 0.001, 0.001 and 0.02 respectively) despite variability in results. At 6 months, P1 amplitude showed significant improvement from baseline in cases (p = 0.010). However, P1 peak time did not show significant recovery (p = 0.65).
mfERG may reveal subclinical electrophysiological retinal dysfunction in eyes with iron IOFB in cases with normal ffERG. P1 peak time may serve as an electrophysiological marker for past retinal damage.
虽然全视野视网膜电流图（ffERG）是检测铁性沉着症生理功能障碍的金标准，但它测量的是整个视网膜的功能。本研究旨在确定多焦视网膜电流图（mfERG）是否可以检测到有铁眼内异物（IOFB）的眼睛中的亚临床铁性沉着症。
本前瞻性病例对照研究纳入了 20 名 20 名患者的 20 只眼，这些患者均有铁 IOFB 留存、清晰的眼内介质和良好的视力（≥20/120）。对侧眼作为对照。这些患者在基线时接受了 ffERG 和 mfERG 检查。在 IOFB 取出的玻璃体切除术（PPV）后，连续进行 mfERG 检查，直到 6 个月。主要结局指标为 mfERG 的 P1 和 N1 波的振幅和峰时。
中位年龄为 25 岁（范围 18-55 岁）。大多数患者（n=20/20）在创伤后 1 个月内就诊。基线 ffERG 显示病例组和对照组之间的“a”和“b”波振幅或峰时均无差异。然而，在 mfERG 中，与对照组相比，<2°视网膜环的 P1 和 N1 波振幅显著降低，P1 波峰时延迟（p=0.001、0.001 和 0.02），尽管结果存在差异。在 6 个月时，病例组的 P1 振幅与基线相比显著改善（p=0.010）。然而，P1 峰时没有明显的恢复（p=0.65）。
在 ffERG 正常的情况下，mfERG 可能会显示出铁性 IOFB 眼中的亚临床电生理视网膜功能障碍。P1 峰时可能是过去视网膜损伤的电生理标志物。
