|Year : 2022 | Volume
| Issue : 2 | Page : 467-468
Commentary: Hyper-reflective spots in acute solar retinopathy
Naresh Babu, Piyush Kohli
Department of Vitreo-Retinal Services, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Madurai, Tamil Nadu, India
|Date of Web Publication||13-Apr-2022|
Department of Vitreo-Retinal services, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Madurai, Tamil Nadu
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Babu N, Kohli P. Commentary: Hyper-reflective spots in acute solar retinopathy. Indian J Ophthalmol Case Rep 2022;2:467-8
Solar retinopathy is defined as retinal injury secondary to prolonged exposure to solar radiation. It is also known as solar retinitis; eclipse blindness/ burn/ retinopathy; and photo retinopathy/ retinitis/ maculopathy. It occurs secondary to the photochemical and/or thermal damage caused by the ultraviolet (UV) rays., The UV radiations have been postulated to cause chemical damage via oxygen-dependent toxicity, which is mediated by free radicals. The incident radiations have been thought to excite the electrons to a higher state and dissipate energy upon returning to the ground state, subsequently leading to the production of reactive oxygen species. Histopathology studies have revealed swelling of the photoreceptor mitochondria as well as fragmentation of the outer segment of rods and cones.
Eclipse retinopathy is associated with diminution of visual acuity but usually carries a good prognosis. The severity of damage has been associated with the duration and number of exposure (s), the pupil diameter, the lenticular status, the clarity of the ocular media, the ocular pigmentation, the body temperature, and the use of medications that can act as photosensitizing agents (such as tricyclic antidepressants, psoralens, tetracyclines, allopurinol, and sulfonamides).
Multiple imaging modalities have been used for diagnosing, prognosticating, and monitoring the patients with photo retinopathy. Owing to its ease and speed of acquisition and excellent reproducibility, spectral-domain optical coherence tomography (SD-OCT) has become the investigation of choice. Eyes with acute injury show hyperreflective areas in the foveal layer, while eyes with chronic injury show a hyporeflective band at the level of the outer and inner photoreceptor layer and discontinuation of the ellipsoid zone (EZ). Jorge et al. reported three OCT patterns in the eyes with late solar retinopathy, that is, optically clear spaces within the entire photoreceptor band, optically clear spaces at the level of the outer segments of the photoreceptor layer with intact inner segments, and fragmentation of the reflective layer of the photoreceptor with loss of external limiting membrane (ELM) and EZ. They suggested that full-thickness involvement of the photoreceptors is associated with poor visual acuity. Similarly, Gulkilik et al. reported that decreased central foveal thickness (CFT) and full-thickness empty spaces beneath the fovea were associated with permanent visual loss in the eyes with late solar retinopathy, whereas defects in mere outer or inner segments of the photoreceptors were not. Kumar et al. proposed a novel index, which they named as photic retinopathy index (PRI), for prognostication. They defined it as the ratio between the maximum defect thickness in the foveal scan and the CFT. They found that the PRI and the maximum defect thickness can be used to predict visual morbidity.
Other imaging modalities have also been used to study the disease. Multifocal electroretinogram shows reduced amplitudes extending over an area (para- and perifovea region) larger than implicated on OCT, which improve with time. Confocal adaptive optics scanning light ophthalmoscopy (AOSLO) shows a large area with ambiguous reflectivity owing to abnormal and non-waveguiding photoreceptors, probably secondary to photoreceptor apoptosis and ensuing atrophy. The shape of this defect resembled the patient's scotoma on Amsler grid. However, the prognostic value of these findings has not been studied. Similarly, no study has evaluated the OCT-angiography findings in these eyes. It would definitely be valuable to understand if solar radiations can affect the retinal or choroidal blood supply also.
We congratulate the authors for reporting the presence of hyperreflective spots (HRS) in the vitreous of a 9-year-old girl who was exposed to solar eclipse for around 10 min just 4 h ago. The authors also reported that these HRS reduced with time as well as correlated with greater anatomic damage and poor visual outcome. Codenotti et al. had earlier reported a 170-micron-wide round hyperreflective formation in the vitreous (70 microns from the retinal surface) just in front of the fovea in a 29-year-old female who was exposed to solar eclipse for 2–3 min 2 days ago. They hypothesized that a rise in the retinal temperature led to thermal and photochemical damage, with consequent vacuolization of the RPE and glial cells with subsequent migration into the vitreous. These HRS are different from the hyperreflective foci (HRF) reported in eyes with diabetic macular edema (DME), age-related macular degeneration (ARMD), retinal vein occlusion (RVO), uveitis, retinitis pigmentosa (RP), and stargardt disease. HRF are focal hyperreflective dots <30 microns in size located in retinal layer(s) with reflectivity similar to the nerve fiber layer and no back shadowing on SD-OCT.
Just like Nakamura et al., the authors in this article have also hypothesized that inflammation may also play a role in the pathogenesis of eclipse retinopathy. Nakamura et al. reported anatomical recovery of the photoreceptor outer layers and significant visual improvement in a 45-year-old male following systemic steroid therapy which was administered 7 weeks after the exposure. Further studies are needed to study the prognostic role of HRS and therapeutic role of steroids in the eyes with solar retinopathy.
| References|| |
Klemencic S, McMahon J, Upadhyay S, Messner L. Spectral domain optical coherence tomography as a predictor of visual function in chronic solar maculopathy. Optom Vis Sci 2011;88:1014-9.
Begaj T, Schaal S. Sunlight and ultraviolet radiation-pertinent retinal implications and current management. Surv Ophthalmol 2018;63:174-92.
Jorge R, Costa RA, Quirino LS, Paques MW, Calucci D, Cardillo JA, et al
. Optical coherence tomography findings in patients with late solar retinopathy. Am J Ophthalmol 2004;137:1139-43.
Gulkilik G, Taskapili M, Kocabora S, Demirci G, Muftuoglu GI. Association between visual acuity loss and optical coherence tomography findings in patients with late solar retinopathy. Retina 2009;29:257-61.
Kumar K, Sen S, Anudeep K, Rajan RP, Kannan NB, Ramasamy K. Anatomical and functional features of photic retinopathy: A spectral domain optical coherence tomography-based longitudinal study. Graefes Arch Clin Exp Ophthalmol 2021. doi: 10.1007/s00417-021-05228-7.
Wu CY, Jansen ME, Andrade J, Chui TYP, Do AT, Rosen RB, et al
. Acute solar retinopathy imaged with adaptive optics, optical coherence tomography angiography, and en face optical coherence tomography. JAMA Ophthalmol 2018;136:82-5.
Kalita IR, Singh HV. Acute eclipse retinopathy: Significance of hyper-reflective foci on optical coherence tomography scan - A case report. Indian J Ophthalmol Case Rep 2022;2:465-7. [Full text]
Codenotti M, Patelli F, Brancato R. OCT findings in patients with retinopathy after watching a solar eclipse. Ophthalmologica 2002;216:463-6.
Fragiotta S, Abdolrahimzadeh S, Dolz-Marco R, Sakurada Y, Gal-Or O, Scuderi G. Significance of hyperreflective foci as an optical coherence tomography biomarker in retinal diseases: Characterization and clinical implications. J Ophthalmol 2021;2021:6096017. doi: 10.1155/2021/6096017.
Nakamura M, Komatsu K, Katagiri S, Hayashi T, Nakano T. Reconstruction of photoreceptor outer layers after steroid therapy in solar retinopathy. Case Rep Ophthalmol Med 2018;2018:7850467.