Chan Wu， Rong-ping Dai*， Fang-tian Dong，Hong Du， and Hua Zhang

Department of Ophthalmology， Peking Union Medical College Hospital，Chinese Academy of Medical Sciences & Peking Union Medical College， Beijing 100730， China

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Bilateral Macular Lesions Following Electrical Injury

Chan Wu， Rong-ping Dai*， Fang-tian Dong，Hong Du， and Hua Zhang

Department of Ophthalmology， Peking Union Medical College Hospital，Chinese Academy of Medical Sciences & Peking Union Medical College， Beijing 100730， China

electrical injury； macular lesion； optical coherence tomography；multifocal electroretinogram

Chin Med Sci J 2016； 31（3）：196-199

H IGH-VOLTAGE electrical injuries can result in a variety of ocular complications. Cataract and macular edema are the most common injuries.1Other injuries include punctate keratopathy, uveitis, macular hole, subretinal macular haemorrhage, and choroidal atrophy.1-4We report a case that optical coherence tomography (OCT) and multifocal electroretinogram (mfERG) clearly demonstrated the bilateral macular lesions following electrical injury, while the fundus examination was nearly normal.

CASE DESCRIPTION

In October, 2013, a 47-year-old man presented with a 3-month history of visual decline in both eyes. Four months before the presentation, he had exposed to approximately 10 000 volts of electricity, which touched his head by accident. He lost consciousness for approximately 5 minutes after the injury, and had burns on the left hand and the left side of his waist. On presentation, the best-corrected visual acuity (BCVA) was 20/40 in both eyes. The slit lamp examination showed multiple, irregular, snowflake-like anterior subcapsular lenticular opacities (Fig. 1). Fundus examination showed bilateral loss of the foveal light reflex and a small yellow spot at the fovea in the right eye (Fig. 2A and B). OCT (3D OCT-2000, Topcon, Japan) revealed bilateral vertical hyper-reflective band extended from the outer segments of the photoreceptors to the inner layer of the retina, and slight interruption of the external limiting membrane and of the inner segment/ outer segment junction at the fovea (Fig. 2C and D). His mfERG (RetiPort ERG system; Roland Consult, Wiesbaden, Germany) demonstrated central reduction of retinal responses in both eyes (Fig. 3). Fundus autofluorescence (FAF, Spectralis-HRA, Heidelberg, Germany) showed no abnormality. He reported no previous history of cataract. Treatment with vitamin C and calcium dobesilate was administered.

During the follow-up visit, the patient reported vision deterioration of the left eye, while the right eye remaining the same. However, a significant increase in mfERG responses was observed two months later after the treatment (Fig. 3). At his last clinical examination, in June, 2014, BCVA was 20/40 in the right eye and 20/70 in the left eye. Slit lamp examination revealed the cataract progression. Fundusexamination was similar to the initial presentation. OCT (Spectralis OCT; Heidelberg, Germany) showed complete resolution of the vertical hyper-reflective band, while only a hyper-reflective spot of the internal limiting membrane could be seen at the fovea (Fig. 2E and F). Based on the examination we considered that the macular function was sufficient and cataract extraction could improve his vision. Phacoemulsification and posterior chamber intraocular lens implantation in the left eye were performed without complication. During postoperative follow-up, his visual acuity improved to 20/20.

DISCUSSION

With the social transformation and wide availability of eletricity, the epidemic of electrical burns is growing.5High-voltage electrical injuries can result in various ocular complications, such as punctate keratopathy, uveitis, cataract, macular edema, macular hole, subretinal macular haemorrhage, and choroidal atrophy, etc.1However, the macular damage clearly demonstrated by OCT in our case has not been described previously. The ocular manifestations may occur immediately or a few years later after injury.5,6The latency period and severity of the disorders vary according to differences in the voltage of the electrical source, the distance of the entry site from the eye, the direction of the current in the body, and the total burn surface area.7In our case, the patient had no subjective symptoms until one month later after the injury. Ophthalmologic examinations revealed both the lenticular and macular disorders of the left eye were more severe than the right eye, which is consistent with the current path.

The pathogenesis of electrical trauma to the eye could be multifactorial; however, coagulation of the proteins seems to be a key factor in this case. The neuronal cells of the retina are minimum resistance in the eye, which would generate less heat. The lack of overlying neurons at the fovea makes it the main resistance in the retina.4Moreover, the retinal pigment epithelium (RPE) cells in the macula contain the highest concentration of melanin, which also constitute the main obstacle to the current flow.7Then coagulation of the retina proteins would probably have occurred in the macula through a thermal mechanism, which appeared as the hyper-reflective band at OCT in our case. It resembles the OCT findings after pattern scanning laser therapy to some degree.8Thus, it may have a similar recovery course. Compared to the macular lesions reported before, the macular recovery of our patient is relatively better, which could be explained by the relatively intact RPE cells in this case. The healthy RPE cells maintain their critical function to phagocytose and degrade the outer segments of the photoreceptors, which improves the recovery of overlying retina. Both the OCT and mfERG findings demonstrated the restoration. Thus, macular lesions like this case may undergo spontaneous remission and improvement in visual acuity without aggressive treatment.

In summary, the combined use of OCT and mfERG inthis case was effective to establish the diagnosis of electrical retinopathy despite its relatively subtle manifestations. This case also contributes to the understanding of the pathogenesis of this condition.

REFERENCES

1. Bae EJ, Hong IH, Park SP, et al. Overview of ocular complications in patients with electrical burns: an analysis of 102 cases across a 7-year period. Burns 2013; 39:1380-5.

2. Rajagopal J, Shetty SB, Kamath AG, et al. Macular hole following electrical shock injury. Can J Ophthalmol 2010; 45:187-8.

3. Liyanage SE, Khemka S, de Alwis DV. Acute subretinal macular haemorrhage following an accidental electrical shock. Eye (Lond) 2006; 20:1422-4.

4. Zablocki GJ1, Hagedorn CL. Chorioretinal atrophy after electrical injury. Digit J Ophthalmol 2011; 17:40-2.

5. Grewal DS, Jain R, Brar GS, et al. Unilateral electric cataract: Scheimpflug imaging and review of the literature. J Cataract Refract Surg 2007; 33:1116-9.

6. Lakosha H, Tremblay F, De Becker I. High-voltage electrical trauma to the eye. Can J Ophthalmol 2009; 44:605-6.

7. Miller BK, Goldstein MH, Monshizadeh R, et al. Ocular manifestations of electrical injury: a case report and review of the literature. CLAO J 2002; 28:224-7.

8. Deák GG, Bolz M, Prager S, et al. Photoreceptor layer regeneration is detectable in the human retina imaged by SD-OCT after laser treatment using subthreshold laser power. Invest Ophthalmol Vis Sci 2012; 53:7019-25.

for publication December 18， 2015.

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