Hyper-reflective track as an imaging biomarker for clinical improvement in photic retinopathy

Manavi D Sindal; Bholesh Ratna; Kurian Jose

doi:10.4103/ijo.IJO_2357_21

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CASE REPORT

Year : 2022 | Volume : 2 | Issue : 2 | Page : 469-471

Hyper-reflective track as an imaging biomarker for clinical improvement in photic retinopathy

Manavi D Sindal, Bholesh Ratna, Kurian Jose
Vitreoretina Services, Aravind Eye Hospital and Postgraduate Institute of Ophthalmology, Puducherry, India

Date of Submission	09-Sep-2021
Date of Acceptance	09-Dec-2021
Date of Web Publication	13-Apr-2022

Correspondence Address:
Manavi D Sindal
Vitreoretina Services, Aravind Eye Hospital, Thavalakuppam, Cuddalore Main Road, Puducherry - 605 007
India

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijo.IJO_2357_21

Abstract

Photic damage occurs due to varied etiologies. In two cases presenting with acute onset symptoms, fundus exam in Case 1 (Welder's arc) showed foveal yellow spot in the left eye. In Case 2 (Solar eclipse), foveal yellow spot was noted bilaterally. Spectral domain Optical coherence tomography revealed disruption of ellipsoid zone and a hyperreflective track extending from outer to inner retina. This hyperreflective track resolved on follow-up and correlated with symptomatic improvement. The hyperreflective track possibly indicates acute photic damage to retina and can serve as a prognostic marker for clinical improvement.

Keywords: Hyperreflective track, photic retinopathy, solar retinopathy, welder's retinopathy

How to cite this article:
Sindal MD, Ratna B, Jose K. Hyper-reflective track as an imaging biomarker for clinical improvement in photic retinopathy. Indian J Ophthalmol Case Rep 2022;2:469-71

How to cite this URL:
Sindal MD, Ratna B, Jose K. Hyper-reflective track as an imaging biomarker for clinical improvement in photic retinopathy. Indian J Ophthalmol Case Rep [serial online] 2022 [cited 2023 Jun 2];2:469-71. Available from: https://www.ijoreports.in/text.asp?2022/2/2/469/342949

Photic retinopathy is caused by various etiologies like solar, welding arc, laser pointers, and operating microscope.^[1–4] The visible light rays, near infrared and intensive near ultraviolet, cross the natural defenses of cornea and lens to reach the retina causing damage. The classical presentation is with metamorphopsia or decreased vision soon after the insult. Clinically, fundus examination reveals a foveal yellow or red spot and spectral domain optical coherence tomography (SD-OCT) demonstrates a disruption of ellipsoid zone (EZ). We describe two cases of photic retinopathy of varied etiology, presenting with classical symptoms and clinical findings. Imaging revealed a hyperreflective track (HRT) in addition to EZ disruption. The track showed resolution with time and is a possible imaging biomarker for photic damage to the retina.

Case Reports

Case 1

A 28-year-old, male professional welder presented with left eye diminished vision, with chromatopsia and metamorphopsia in both eyes since 5 days. He occasionally did not use any standardized protective eyewear during welding. His best-corrected visual acuity (BCVA) was 6/6 and 6/6p respectively. Anterior segment examination was unremarkable. Fundus showed small parafoveal pigmentary changes with normal foveal reflex in the right eye and a foveal yellow spot in the left eye [Figure 1]a and [Figure 1]b. These changes were appreciated more prominently on infrared reflectance imaging [Figure 2]a and [Figure 2]b. SD-OCT [Figure 3]a and [Figure 3]b, revealed a HRT from outer to inner retina at fovea in both eyes, with disruption of EZ in the left eye. The external limiting membrane (ELM) was seen to be traversed by the HRT and appeared to be disrupted. A diagnosis of photic retinopathy secondary to welding arc exposure was made and a trial of oral steroid was given. (Dose of 1 mg/kg body weight, tapered every 5 days). On review 3 weeks later, vision had improved, metamorphopsia reduced with no chromatopsia, and patient was symptomatically better. There was resolution of HRT and an intact ELM [Figure 3]c and [Figure 3]d in both eyes on SD-OCT. The EZ disruption in the left eye was seen to persist.

Figure 1: Multicolour fundus photograph- Case 1- (a) Right eye with pigmentary changes at fovea. (b) Left eye of case 1 showing foveal yellow spot. Case 2 – (c) Right eye and (d) Left eye- both showing pigmentary changes as a dark spot

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Figure 2: Infrared reflectance imaging Case 1 – (a and b) Right and left eye, respectively, highlighting the pigmentary changes, which are more diffuse in the right eye. Case 2– (c and d) Right and left eye, respectively – highlighting circumscribed pigmentary changes

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Figure 3: Case 1 Top Row – At presentation – Right eye (a) and left eye (b), spectral domain optical coherence tomography showing hyperreflective track from outer to inner retinal layers at fovea in both eyes. Retinal pigment epithelial alterations are seen para foveally in the right eye. The left eye shows disruption of ellipsoid zone and the external limiting membrane at fovea. Bottom row – Three weeks later – SD-OCT Right eye (c) and Left eye (d) show appreciable resolution of hyperreflective tracks, intact ELM. The ellipsoid zone disruption in the left eye has reduced in size

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Case 2

A 14-year-male presented with right eye defective vision since 4 days, following viewing a solar eclipse without any protective measures. He also experienced metamorphopsia and chromatopsia. His BCVA was 6/6p bilaterally. Anterior segment was unremarkable. Fundus showed foveal pigmentary changes [Figure 1]c and [Figure 1]d. Infrared reflectance imaging showed well-circumscribed areas of hyperpigmentation. [Figure 2]c and [Figure 2]d. SD-OCT [Figure 4]a and [Figure 4]b showed foveal disruption of ELM, EZ, and HRT from outer to inner layers. A diagnosis of photic retinopathy secondary to solar eclipse viewing was made. Following a trial of oral steroid (Dose of 1 mg/kg body weight, tapered every 5 days) two months later, he was symptomatically better with improved vision and reduction of metamorphopsia and resolution of chromatopsia. The SD-OCT showed resolution of HRT, an intact ELM with persistent EZ disruption [Figure 4]c and [Figure 4]d in both eyes. At a review 10 months later, his ocular and SDOCT findings remained status quo.

Figure 4: Case 2 Top Row- At presentation – Right eye (a) and Left eye (b), spectral domain optical coherence tomography showing hyperreflective track from outer to inner layers, formation of degenerative space in outer nuclear layer and ellipsoid zone disruption at fovea in both eyes. External limiting membrane is traversed by the hyperreflective track. Bottom row – Two months later – S D-OCT Right eye (c) and Left eye (d) show resolution of hyperreflective tracks with persistent defect in ellipsoid zone. An intact external limiting membrane is noted

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Discussion

Photic retinopathy is usually seen in younger population^[2],[5] and can leave permanent changes in macula. The vision involvement can vary, with persisting symptoms or improvement over time.^[2] The usual presentation is with symptoms of blurred vision, a central or paracentral scotoma, chromatopsia, metamorphopsia, photophobia, and headache. Exposure to welding arc commonly causes photoelectric keratitis with some patients also developing maculopathy.^[3]

Photic damage to retina can be photomechanical, photothermal, or photochemical.^[4] Photomechanical damage occurs by rapid input of energy in melanosomes present in retinal pigment epithelium (RPE), with formation of microcavitation bubbles and resultant shock waves permanently damage the RPE. Photothermal damage occurs when irradiance raises temperature by more than 10° C than surrounding retina. In photochemical toxicity, the photic energy gets concentrated at RPE and photoreceptors and leads to production of free radicals, causing RPE cell disruption and photoreceptor outer segment damage.^[4]

Diagnosis of photic retinopathy is usually made with a temporal association of exposure to UV rays and onset of classical symptoms. The described foveal red or yellow spot, though a classic finding, is not necessarily always present.^[3] SD-OCT is a more sensitive tool in detecting photic damage to macula. The most commonly described SD-OCT finding in photic retinopathy is the defect in ELM and EZ.^{[2],[3],[5],[6]} In our cases described, the EZ disruption was evident in both eyes of case 2, but only in one eye of case 1. In acute phase of insult, we noted HRT extending from outer to inner retina and traversing the ELM in both eyes of both cases. This HRT resolved on follow-up, with restoration of ELM and symptomatic improvement in vision, even though the EZ defect persisted.

These HRTs have been previously described in literature with varied terminologies - Intraretinal nonreflective spaces and increased reflectiveness of inner layers in acute phases following solar eclipse-related damage. This hyperreflectivity resolved over time.^[5],[7] Abdellah et al.^[2] describe hyperreflective spot in inner retinal layers in a subset of eyes with acute onset symptoms of welding arc associated photic retinopathy. They note that these lesions disappeared over time with persistence of the EZ defect. When describing changes in acute to chronic photic retinopathy, Arora et al.^[6] describe increased hyperreflectivity on SD-OCT at fovea, extending from RPE to inner layers, which resolved over time with the resolution of symptoms. The cases in this series that presented late had only EZ disruption.

The sudden increased concentration of energy at the level of RPE and photoreceptors possibly leads to conduction of high-intensity microcurrents through retinal layers. The resultant structural alterations in cells from outer to inner retinal layers is appreciated as hyperreflective tracks on SD-OCT.^[7] Over time, the RPE and other neuroglial cells proliferate, their synapses are restored but photoreceptors leave degenerated spaces in outer layers. There is no established treatment modality for photic retinopathy, with some resolution of lesions with partial visual improvement noted spontaneously. The photic damage possibly induces subclinical inflammation, which systemic steroids can help resolve.^[7],[8] We used steroids in our cases so as to offer a treatment modality, but our data is insufficient to state if the improvement was spontaneous or the result of steroid use.

Conclusion

The hyperreflective tracks can be a possible imaging biomarker for acute photic damage with the resolution over time an indicator for improvement. As the EZ defect persists in most cases, it is the most commonly reported finding on SD-OCT in eyes with photic retinopathy. The use of standard protective eye wear while working with welding arc or viewing a solar eclipse is mandatory.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

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