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Optical coherence tomography findings in early solar retinopathy
  1. MARTIN BECHMANN,
  2. OLIVER EHRT,
  3. MARTIN J THIEL,
  4. NADINE KRISTIN,
  5. MICHAEL W ULBIG,
  6. ANSELM KAMPIK
  1. Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany
  1. Martin Bechmann, Universitäts Augenklinik, Mathildenstrasse 8, 80336 München, Germany mbechman{at}ak-i.med.uni-muenchen.de

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Editor,—Visual deterioration caused by watching a solar eclipse has been recognised from the time of Plato. The aetiology of solar retinopathy has been attributed to photochemical effects, which may be enhanced by elevated tissue temperature.1Typically, a small yellow spot may be noted in the foveolar area immediately after exposure. Histopathological studies of solar retinal lesions revealed retinal pigment epithelium (RPE) and photoreceptor damage.1 2 We present two patients with acute, severe solar retinopathy after observation of the total eclipse on 11 August 1999. Funduscopic findings were accompanied by optical coherence tomography (OCT) investigation of the macula.

CASE REPORTS

Case 1

An 18 year old man presented 24 hours after watching the total eclipse without appropriate protection. Total exposure time was approximately 20 minutes. During direct viewing the patient kept his right eye closed. One hour after observation he noted blurred vision and a central scotoma on the left eye. Best corrected visual acuity was 0.8 in the right and 0.1 in the left eye. Fundus examination of the right eye did not show any pathology. Funduscopy of the left eye revealed a yellow lesion in the fovea, surrounded by a circular red area (Fig 1). OCT was performed 48 hours after exposure. OCT examination of the right eye showed no pathology. In the left eye, a hyperreflective area in the fovea was found (Fig 2A). All retinal layers in the fovea were affected. The hyperreflective area closely resembled the yellow spot seen funduscopically. There was no significant difference in retinal thickness between the right and the left eye (106 μm/110 μm). Nine days after exposure visual acuity was 0.8 in the right eye and 0.16 in the left eye. Funduscopy showed the yellow lesion of the left fovea resolving and its margins beginning to fade. An OCT scan revealed that the previously hyperreflective foveal area converted to a normal reflectivity (Fig2B).

Figure 1

Acute stage of solar retinopathy showing a yellow lesion surrounded by a circular red area (patient 1, left eye).

Figure 2

(A) OCT examination of the same eye 48 hours after exposure revealed a hyperreflective area in the fovea affecting all retinal layers. No increase in retinal thickness could be demonstrated. The location of the OCT scan is shown on the corresponding fundus photograph (Fig 1). (B) OCT examination 9 days after exposure. The hyperreflective area in the fovea was no longer visible, whereas an increasing alteration of the RPE and choriocapillary layer could be demonstrated. Visual acuity increased from 0.1 to 0.16. Still no change in retinal thickness occurred.

Case 2

A 26 year old woman complained of blurred vision and central scotoma after watching the eclipse without eye protection. Total exposure time was 5 minutes. Forty eight hours after exposure visual acuity was 1.0 in the right and 0.8 in the left eye. Fundus examination showed a small yellow round lesion in the fovea of both eyes. On OCT, a hyperreflective area in the centre of the fovea was demonstrated in both eyes. Similar to case 1, all layers of the fovea were affected. Retinal thickness (110 μm/118 μm) was within the normal range.

COMMENT

Solar retinopathy is characterised by a yellow foveolar dot and a central scotoma.3 For the first time we describe OCT findings of patients suffering from solar retinopathy. The main finding was a hyperreflective area involving all foveolar retinal layers without showing any sign of retinal oedema. It correlated in size and location with the characteristic funduscopically visible yellow dot. At present, the origin of this well delineated area of hyperreflectivity is unclear. Moreover, histopathological analysis1 2 of solar retinopathy has demonstrated that mainly the pigment epithelium and outer segments of the photoreceptor layer are damaged. The OCT scan however showed pathological appearance of all retinal layers. In one patient we have been able to repeat OCT investigation 9 days after solar exposure, revealing that the retinal changes were reversible, but delineating increasing pathology in the RPE and choriocapillaris layer.

In addition, macular oedema, which has been described in the literature before,4 5 could not be demonstrated by OCT. On OCT examination, no significant increase in retinal thickness could be observed when comparing the affected and unaffected eye (case 1) or absolute values of both affected eyes (case 2). To the best of our knowledge, none of these OCT findings have been published before by other investigators.

Acknowledgments

The authors do not have any commercial or proprietary interest in any of the products mentioned in this article

References

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