Chronic dry eye is a disease of the surface of the eye that can happen when your eyes do not make enough tears or there is a problem with the tears that are made. Chronic dry eye may also be called dry eye syndrome (DES), dry eye disease (DED), or keratoconjunctivitis sicca.1
Those with dry eyes often report sensitivity to light, also known as photophobia. In a study of 236 people with dry eye disease, 3 out of 4 reported pain or discomfort when exposed to light. With an estimated 16.4 million people diagnosed in the United States, dry eye with light sensitivity can affect the quality of life for millions of Americans.2,3
What is light sensitivity?
Light sensitivity is an abnormal, painful, or uncomfortable sensation when exposed to light. Various sources of light can cause discomfort in those with dry eyes, including:4-8
- Sunlight – The sun emits visible light and ultraviolet (UV) light. UV light is a type of radiation that is responsible for causing sunburns. Eye exposure to direct UV light can damage the eyes.
- Fluorescent light – This type of light is produced when a chemical reaction occurs between gas and energy inside a glass tube. The glass in the tube glows with fluorescent light. This light is common in office buildings, grocery stores, and gyms.
- Incandescent light – This type of light is produced when a tiny coil inside the light bulb is heated by electricity, making it glow. This is found in the common home light bulb.
What is the cause?
A painful or uncomfortable reaction to light is not a disease itself. Rather, it can occur because of conditions of the eye that cause irritation.
The exact reason why dry eye syndrome can lead to light sensitivity is not well known. However, some experts believe that an irregular, dry ocular surface or abnormal tear film can cause light to scatter in many directions when it reaches the surface of the eye. This scattered light can cause significant discomfort in the eye. In contrast, a smooth tear film and healthy eye surface focus light without scattering.2,9
Inflammation related to chronic dry eye may also cause light sensitivity. In particular, light causes the pupil of the eye to constrict (get smaller). When bright light enters an inflamed eye, the rapid contraction of muscles that constrict the pupil may result in eye pain or discomfort. This discomfort may be worse at night time, such as with bright oncoming headlights while driving. This is because the pupil usually is in a dilated (larger) position at night.2,9
People with lighter-colored eyes may be more sensitive to light. Lighter eyes have less light-protecting pigmentation in the iris, or colored part of the eye, compared to those with darker eyes.4
How to manage
Even though a large number of people are affected, light sensitivity is still not well understood. The best way to manage light sensitivity is to find out what is causing it. Once the problem is found and treated, sensitivity to light may be managed.
Many different types of drugs can cause dry eyes and may lead to or worsen light sensitivity. Talking to your doctor about your symptoms and the drugs you are taking may be helpful to get to the bottom of your light sensitivity symptoms.
There are some methods you can take that may help you manage light sensitivity. Some of these may include:4,10
- Avoid bright sunlight and artificial light when possible
- Wear a wide-brimmed hat and sunglasses with UV protection when exposed to sunlight
- Choose photochromic lenses when possible. These are glasses with clear or nearly clear lenses indoors that automatically darken when exposed to sunlight.