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Evolution of Severe Lightning Maculopathy Visualized With Spectral Domain Optical Coherence Tomography Blair Armstrong Christopher Fecarotta, MD Allen C. Ho, MD Darrell E. Baskin, MD
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ABSTRACT
The authors report a case of lightning maculopathy with serial spectral domain optical coherence tomographs that, for the first time, elegantly illustrate the natural history of this uncommon, ominous condition. [Ophthalmic Surg Lasers Imaging 2010;41:S70-S73.] INTRODUCTION
Lightning is the second leading cause of weatherrelated death (after floods) in much of the world.1,2 Lightning has an estimated 10,000 to 200,000 amperes of current and voltage ranging from 20 million to 1 billion volts.3 Injuries are generally classified as direct strike (which is often fatal), contact injury, side flash, or ground strike.3,4 Eyelid burns, motility disturbances, ocular surface disease, pupillary abnormalities, cataracts, macular holes, macular edema, optic neuropathy, retinal detachment, central retinal artery occlusion, central retinal vein occlusion, and uveitis have been reported.4 We describe a case of lightning maculopathy with serial spectral domain optical coherence tomographs (SD-OCT) that elegantly illustrate the natural history of this pernicious condition.
B Figure 1. (A) This fundus photograph of the left eye taken at presentation demonstrates myopic conus and a blunted foveal light reflex. (B) This fundus photograph, taken 2 months later, demonstrates a focal area of mild hypopigmentation within the foveola.
CASE REPORT
A 29-year-old myopic woman was struck by the side flash of a lightning strike that initially hit a tree while she was hiking in the Pocono Mountains; she lost consciousness and hit the right side of her head on a rocky prominence. She had no memory of the event. Since the accident, she had noted occasional
From the Retina Service, Wills Eye Institute, Philadelphia, Pennsylvania. Originally submitted February 14, 2010. Accepted for publication April 14, 2010. The authors have no financial or proprietary interest in the materials presented herein. Address correspondence to Darrell E. Baskin, MD, Wills Eye Institute, Retina Service, 840 Walnut Street, Suite 1020, Philadelphia, PA 19107. E-mail:
[email protected] doi: 10.3928/15428877-20101031-02
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flashes in the right eye and blurry vision with a mild color desaturation in the left eye. Three days after the injury, she was referred to the Retina Service of Wills Eye Institute for ophthalmic evaluation. On initial examination, corrected visual acuities were 20/25 in the right eye and 20/60 in the left eye. Intraocular pressures were normal. Color plates were full in both eyes; however, subjective red desaturation was noted in the left eye. The visual field by confrontational examination was normal in the right eye, but was somewhat constricted temporally in the left eye. There was a mild afferent pupillary defect noted in the left eye. The right eye had a subconjunctival hemorrhage in the inferotemporal quadrant, but had an otherwise normal anterior segment. The conjunctiva of the left eye had mild temporal chemosis and the left pupil demonstrated exaggerated hippus iridis. The lenses were clear in both eyes. Dilated fundus examination revealed temporally tilted discs and peripapillary atrophy in both eyes. There was no Weiss ring in either eye, and an abnormal foveal light reflex was noted in the left eye (Fig. 1). Results of the Watzke–Allen test were negative. On further testing, the fluorescein angiogram revealed no significant abnormalities. SD-OCT of the right eye was normal; however, the left eye demonstrated a double “U” shape of the inner foveal contour and focal elevation of the foveolar photoreceptor inner segment/outer segment junction (Fig. 2). During the next 4 months, the patient was observed closely with serial SD-OCT and fundus photographs. Two weeks after initial presentation, some peripheral pigmentary changes were noted in the left eye (Fig. 3, photo-
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Figure 2. Each of these images are horizontal, transfoveal, oversampled spectral domain optical coherence tomographs of the left eye obtained with Spectralis (Heidelberg Engineering, Vista, CA). Figure 2A was acquired at initial presentation (3 days after injury). Inner foveal contour has central acute elevation (double-“U” shape); there is focal elevation of foveolar photoreceptor layers immediately beneath with a trace subfoveal blister of fluid. Figure 2B was acquired 3 weeks after injury. The inner foveal contour has straightened and it appears that the central foveolar photoreceptors have vanished, as implied by the large hyporeflective cystic changes within the foveola. Also, note the widespread disruption and loss of the inner segment/outer segment (IS/OS) junction between the fovea and the nerve. There is also increased reflectivity within the choroid beneath the center of the fovea, which suggests focal loss of the overlying retinal pigment epithelium. Figure 2C was acquired 5 weeks after injury. The inner foveal contour appears more normal in its depression. There is still a persistence of subfoveal fluid in a block-shaped area, which suggests a mechanical loss of tissue rather than an exudative etiology. The IS/OS junction is still largely disrupted in the fovea and nasal to it. Figure 2D was acquired two months after injury. The subfoveal fluid appears to be resolving. The nasal choroid appears more reflective than the temporal choroid, which suggests retinal pigment epithelium atrophy. Figure 2E was acquired 4 months after injury. There is complete resolution of the subfoveal fluid, and there is marked thinning of the neurosensory retina at the center of the fovea and relative thinning of the nasal retina compared to the temporal retina, especially when the nerve fiber layer is not included in the comparison. The IS/OS junction immediately nasal to the center of the fovea does appear more intact than the previous scan.
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Figure 3. Color fundus photograph of the periphery of the left eye taken 4 months after injury. This shows the hyperpigmented retinal pigment epithelium changes that were first noted 2 weeks after injury.
graph taken 4 months after presentation). Two months after initial presentation, a Humphrey visual field test was performed and confirmed the temporal visual field constriction noted at presentation (Fig. 4). Two months after initial presentation, it was also noted that there were some focal hypopigmented areas in the foveola (Fig. 1). Unfortunately, her fovea became atrophic (Fig. 2) and her vision ultimately declined to 20/200 in the left eye. DISCUSSION
Lightning damage to tissue occurs through direct electrolysis, resistance-induced heat, or mechanical disruption by the associated shock wave.5 Secondary damage from edema, ischemia, or reperfusion injury also occurs.3 The most common ocular sequelae are posterior subcapsular and/or anterior subcapsular cataract formation (in 1772, St. Yves reported the first ocular injury due to lightning: cataract)6; increased resistance through the lens capsule or iris pigment epithelium can cause denaturation of lens proteins.5,7,8 The pigment granules of the iris, pigment epithelium, and choroid act as resistors to electrical conduction.8 Within the retinal pigment epithelium, this resistance leads to heat production that places the overlying retina at risk of thermal injury; of note, the intracellular melanin content is highest within the macular retinal pigment epithelium and thus predisposes the fovea to lightning-related damage.5,9 Lightning maculopathy
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Figure 4. Humphrey visual field (SITA-Fast 24-2) of the left eye was performed 2 months after injury and demonstrates superior greater than inferior arcuate scotomas.
often manifests as cystoid macular edema resembling macular hole formation.10 Our patient presented with a severe, progressive maculopathy secondary to side flash lightning strike. Handa and Jaffe9 reported a case of side flash lightning strike that resulted in bilateral foveal cystic changes and unilateral changes that mimicked a full-thickness hole, but had negative results on Watzke–Allen tests bilaterally. After bilateral cataract extraction, both eyes regained 20/20 visual acuity. Moon et al. also reported a case of lightning maculopathy with macular edema, cystic changes, a fundus appearance similar to a macular hole, a negative result on Watzke–Allen test, and final visual acuity of 20/50.11 Their report and that of Rivas-Aguino et al.10 account for the only two published OCT findings of lightning maculopathy, and neither of them obtained OCT imaging before the retina had become atrophic. Additionally, their OCT images were obtained by earlier generation systems that were not able to visualize the photoreceptor layers as well as SD-OCT can. This report documents for the first time the initial focal elevation of the inner segment/outer segment junction, the accumulation of outer retinal cystic changes, obliteration of the nasal photoreceptor layer, and the eventual atrophy of the fovea in a pernicious case of lightning maculopathy as seen through the interferometer of SD-OCT.
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REFERENCES 1. Ritenour AE, Morton MJ, McManus JG, Barillo DJ, Cancio LC. Lightning injury: a review. Burns. 2008;34:585-594. 2. O’Keefe Gatewood M, Zane RD. Lightning injuries. Emerg Med Clin North Am. 2004;22:369-403. 3. Norman ME, Albertson D, Younge BR. Ophthalmic manifestations of lightning strike. Surv Ophthalmol. 2001;46:19-24. 4. Lee MS, Gunton KB, Fischer DH, Brucker AJ. Ocular manifestations of remote lightning strike. Retina. 2002;22:808-810. 5. Lagreze WD, Bomer TG, Aiello LP. Lightning-induced ocular injury. Arch Ophthalmol. 1995;113:1076-1077. 6. Noel LP, Clarke WN, Addison D. Ocular complications of lightning.
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J Pediatr Ophthalmol Strabismus. 1980;17:245-246. 7. Biro Z, Pamer Z. Electrical cataract and optic neuropathy. Int Ophthalmol. 1994;18:43-47. 8. Augustin AJ, Koch F, Boker T. Macular damage following lightning strikes. Ger J Ophthalmol. 1995;4:214-216. 9. Handa JT, Jaffe GJ. Lightning maculopathy: a case report. Retina. 1994;14:169-172. 10. Rivas-Aguiño PJ, Garcia RA, Arevalo JF. Bilateral macular cyst after lightning visualized with optical coherence tomography. Clin Experiment Ophthalmol. 2006;34:893-894. 11. Moon SJ, Kim JE, Han DP. Lightning-induced maculopathy. Retina. 2005;25:380-382.
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