Our eyes naturally provide us with a protective tinting, known as the pigmented epithelium. It wraps around our eye, similar to saran wrap around a ping-pong ball. But sometimes our pigmented epithelium isn’t enough to filter out the light.
Light sensitivity, also known as photophobia, tends to be a major reason patients seek eye care consultation.
The pigmented epithelium (protective tinting) in your eyes can be viewed when looking at the color part of your eye known as the iris. Differences in iris color can be related to experiencing more or less light sensitivity than someone else.
Generally speaking, patients with lighter color irises, such as blue or gray, experience more light sensitivity than someone with brown eyes. The density of pigment in light eyes is less than that of a darker colored iris. When light hits a dark-colored iris, the higher density in pigment blocks the light rays. This is similar to how a pair of sunglasses blocks light. When light hits a lighter colored iris, more light is transmitted through to the back of the eye resulting in more light sensitivity. Additionally, the pigment in the back of the eye (retina) may also be less dense in a patient with lighter colored eyes, thus resulting in even more light sensitivity.
Depending on the severity, light sensitivity could be relatively harmless or a symptom of an underlying ocular disease. Mild light sensitivity usually doesn’t affect one’s ability to do everyday tasks. Patients with lighter colored eyes usually go about their day just fine, by using sunglasses or protective tints to aid in relief of light sensitivity.
On the other hand, patients with ocular or oculocutaneous albinism have minimal to no pigment in the eye for protection, which can cause photophobia to be debilitating to daily activities such as reading, working on a computer, or viewing distance objects on a sunny day.
When light sensitivity occurs, the natural solution is to use tinted lenses. Sunglasses provide a protective layer to block and filter the amount of light entering the eye, thus providing patients with relief from light sensitivity.
In the past year or two, contact lenses have been developed to include transitional tinting, similar to activated tint of glasses when UV light hits the lens. These glasses or contact lenses are called transition lenses.
Although mild forms of light sensitivity may be normal, it can also suggest an underlying ocular disease. So it’s important to seek advice from an eye care professional.
The first ocular condition that comes to mind when I hear patients say their eyes are sensitive to light is uveitis. Uveitis may be idiopathic, from trauma, or as a result of an underlying autoimmune disease. It consists of underlying inflammation to the pigment layers in the eye (uvea/iris), and is typically treated with ocular steroid drops.
Light sensitivity may also suggest an underlying corneal disorder. Corneal conditions that may cause light sensitivity include dry eyes, superficial punctate keratitis (spk), herpes simplex keratitis (HSK), herpes zoster keratitis (HZK), corneal abrasion, recurrent corneal erosion (RCE), corneal ulcer, and contact lens acute red eye. Typically these conditions will also produce a foreign body sensation and tearing along with light sensitivity. There are various treatments involved in these conditions. If you feel that you may have light sensitivity related to these conditions you should seek eye care consultation as soon as possible.
The function of the pupil is to constrict and focus light on the retina. When the pupil constricts, it prevents light from entering the eye, thus preventing photophobia. Patients with irregular pupils may have a defective constrictor muscle, thus giving them more light sensitivity.
Dilating pupils with special eye drops allows your doctor to focus on the retina and look for diseases such as cataracts, glaucoma, macular degeneration, and retinal diseases. Once dilated, patients may experience light sensitivity, which should subside once the dilation times nears its end, typically in about 4-6 hours. Patients with lighter colored eyes tend to remain dilated longer than patients with darker colored eyes.
Patients also tend to experience light sensitivity following corneal surgery, cataract surgery, and conjunctival surgery. Light sensitivity early in the surgical period is normal, and typically subsides in 1-2 weeks. Patients are always treated with topical medication to help prevent and resolve light sensitivity during their post-op period.
As you can see, light sensitivity has many possible causes. If you’re experiencing symptoms, we encourage you to seek eye care consultation. At Milan Eye Center we see many patients with light sensitivity or photophobia and have extensive experience in treating patients to ensure it resolves in a timely manner. Please reach out to us if you are suffering from photophobia.