By Megan A. Mason, MPH, NRP, FFII
With thousands expected to watch the total solar eclipse on April 8, 2024, many of whom are traveling for an optimal review, it begs the question 鈥� is it all fun and games or can someone get hurt? Solar eclipses, while spectacular events, and for many, a once-in-a-lifetime event, are not without risks, especially if proper safety precautions are not taken.
What is solar retinopathy?
Solar (photic, eclipse) retinopathy is caused by exposure to intense light, which causes damage to the retina [1]. Specifically, the intense solar exposure causes burning of the macula, a light-sensitive part of the retina at the back of the eye [2]. This is the part of the eye that allows people to read and recognize faces. The damage, however, occurs primarily through a photo-oxidative pathway, as opposed to a direct thermal burn [3]. Even seconds of unprotected eclipse viewing can cause temporary or permanent macular damage, and once retinal tissue is destroyed, it cannot regenerate, potentially resulting in permanent central vision loss [2].
The normal anatomical structures of the eye absorb and filter the shortest wavelengths of UV light (UV-C, <280 nm), while the adult lens also absorbs UV light in the UV-B spectrum (280-320 nm) and part of the UV-A spectrum (315-440 nm), specifically, UV rays less than 365 nm [3]. The aqueous anterior chamber of the eye absorbs the longer wavelengths located in the infrared (IR) spectrum (IR B and C 1,400 鈥� 10,000 nm). Phototoxicity occurs primarily from the higher energy UV-A and shorter visible light waves. The absorption of these waves leads to generation of reactive oxygen species and subsequent damage to the epithelial cells and surrounding photoreceptors, resulting in retinal damage and central vision loss [3].
While eclipse viewing is one of the most common causes of solar retinopathy, it is not the only cause. Other causes include sun gazing, staring at a laser pointer, welding and staring at bright lights [1].
Solar retinopathy symptoms
As solar retinopathy is unlikely to cause any pain or discomfort, symptoms typically appear within 4 to 6 hours, although some people may notice symptoms after 12 hours or longer [4]. Symptoms include blurry vision, headache, blind spots (scotoma) in the central field of vision in one or both eyes, increased sensitivity to light, visual distortions (metamorphopsia), objects appearing smaller than they are (micropsia), and changes in the way color is seen (dyschromatopsia) [1,4].
Solar retinopathy diagnosis
Unfortunately, there are no outward signs of solar retinopathy that will be visible to the field provider. However, based on a thorough history and physical exam, a provider can maintain a high index of suspicion for ocular damage due to solar retinopathy.
Diagnosis is made through a history of light exposure and thorough examination by an ophthalmologist, during which the eyes are dilated to examine the retina. Additionally, a photograph of the retina or fundus may be taken to observe for damage. If the damage is moderate to severe, it should be visible during examination, however, minor damage may not be visible and may require additional testing. Additional diagnostic testing may include visual field testing, optical coherence tomography (OCT), fluorescein angiography (FA), fundus autofluorescence (FAF), and multifocal electroretinography (mfERG) [1,3].
Visual field testing is used to assess for blind spots in vision, while OCT is a specialized imaging test that shows microscopic cross-sectional images of the retina [1]. A change unique to solar retinopathy, involving damage to the outer layers of the retina responsible for central vision (fovea), can be seen on OCT, allowing for definitive diagnosis [1]. FA assesses blood flow in the retina, and can show damage known as a 鈥渨indow defect鈥� that can assist with diagnosis confirmation [1]. MfERG may show reduced function in the para-fovea and perifovea [3]. While this function typically improves over time, functional deficits may remain visible on mfERG in chronic cases and may be beneficial in the diagnosis [3].
As with any patient, a field provider should obtain a complete patient history, including any recent significant light exposure, such as eclipse viewing, and should determine whether the patient wore specialized 鈥渆clipse鈥� glasses during the potential exposure. Additionally, a complete physical exam, including neurological exam, should be completed to rule out other potential causes of visual symptoms, such as stroke. Anyone suspected of experiencing solar retinopathy should be evaluated as soon as possible by an ophthalmologist to determine the extent of the damage.
Solar retinopathy treatment and prognosis
Currently, there is no available treatment for solar retinopathy, though many symptoms often resolve on their own within 3-6 months. Vision changes present after 6 months are likely to be permanent, although many individuals improve to at least 20/40 vision within the first few months. Some individuals may experience permanent distortions or blind spots in their central vision, which cannot be corrected [1].
How to protect yourself during the solar eclipse
Providers, whether working the field or eclipse gazing on their own, should take appropriate precautions to protect themselves or their families from becoming the victim. Recommendations include:
- Do not view the eclipse with the naked eye.
- Do not view the eclipse through a camera (cell phone or regular), binoculars, telescope or while wearing standard sunglasses.
- Utilize shade no. 14 welder鈥檚 glasses or aluminized mylar plastic sheeting, or filters that meet the ISO 12312-2 standard for viewing.
- [2].
This year鈥檚 total solar eclipse promises to be an exciting event, with watch parties and other special events scheduled throughout the expected path. However, if the appropriate precautions are not taken, it may also result in missing other important moments in life because of vision loss due to solar retinopathy. As providers, we owe it to our patients to make sure we have the most up-to-date information and to make sure that we protect ourselves.
Stay safe out there everyone!
References
- Scott C. (2022, August 19). Solar retinopathy. 鈥淎merican Association for Pediatric Ophthalmology.鈥�
- Bressler NM, Kong J, Ar茅valo J. (2024, March 8). Safe viewing of solar eclipses. 鈥淛AMA Network.鈥�
- Chen KC, Jung JJ, Aizman A. (2013, October 1). Solar retinopathy: Etiology, diagnosis, and treatment. 鈥淩etinal Physician,鈥� 10(October 2013).
- Medeiros S. (2023, April 20). Think you hurt your eyes watching the eclipse?. 鈥淎merican Academy of Ophthalmology.鈥�
About the author
Megan A. Mason MPH, NRP, FFII, is a firefighter/paramedic and EMS educator in rural Western Pennsylvania. She holds a Bachelor of Arts in Health Science from La Roche University and a Master of Public Health from Kent State University, where she focused on the intersection of public health and paramedicine. Currently, her focus is on improving the quality of education available to rural EMS providers, as well as community education focusing on CPR, first aid, and Stop the Bleed in rural areas.