The Royal College of Ophthalmologists is urging people planning to watch this week’s solar eclipse to protect their sight, warning that even brief exposure to the sun can cause lasting vision damage.
“The safest way to enjoy the eclipse is to observe it indirectly, such as by watching a live broadcast,” says College President Mohamed Elalfy, a consultant ophthalmologist.
He cautions: “Looking directly at the sun during a solar eclipse can cause damage to the retina, potentially damaging the cells responsible for sharp central vision. Crucially, the retina has no pain receptors, so people will not feel the damage as it happens.
“Symptoms may only become apparent several hours later and can include blurred vision, a central blind or dark spot, distorted vision, reduced colour perception and increased sensitivity to light. While some people recover over weeks or months, others can be left with permanent visual impairment.”
The College’s advice is simple: never look directly at the sun without appropriate protection. Ordinary sunglasses, even very dark ones, do not provide adequate protection. Neither do binoculars, telescopes or cameras unless the equipment has an appropriate, professionally fitted solar filter placed in front of the objective lens. Any device used for viewing the sun needs appropriate protection and should be verified and validated in line with strict industry standards.
Safe indirect methods of viewing a solar eclipse include pinhole projection and appropriately designed and certified solar-projection equipment such as eclipse glasses that meet ISO 12312-2, as well as television or online broadcasts.
The College also stresses that, even when only a small part of the sun remains visible during an eclipse, sufficient radiation can reach the retina to cause injury.
Anyone who notices a change in their vision after looking at the sun should seek prompt advice from an eye-care professional.
Following the total solar eclipse visible across parts of Europe in August 1999, College members contributed to research documenting the ophthalmic impact of unsafe viewing. They conducted a national survey that identified 70 patients with eclipse-related visual loss, with most cases resulting from direct viewing of the eclipse without appropriate eye protection. Although some recovered useful vision, others were left with persistent visual deficits, highlighting that retinal injury from eclipse viewing can be permanent.