Powerful UV rays can cause temporary sun blindness on sunny days, especially when light reflects off of water or snow. Your eyes can sustain damage from excessive sun exposure.

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Temporary sun blindness occurs when exposure to bright sunlight interferes with your vision.

This can manifest as photokeratitis, painful eye inflammation caused by UV rays burning the cells covering the clear cornea. Swelling of the cornea reduces its transparency, resulting in a sudden loss of visual acuity.

If you experience temporary sun blindness and often have to squint or close your eyes, you’re not alone. While most people understand that UV rays can cause skin cancer, many are unaware of the effect of UV radiation on the eyes. When you’re outside on a sunny day without protective eyewear, your eyes may be at risk of damage.

People with lighter eyes may be more prone to temporary sun blindness. This is because their eyes have less melanin pigment to absorb UV radiation and protect their photoreceptor cells.

You may also experience sun blindness if you drive or travel often or regularly engage in activities like skiing and mountain climbing.

Symptoms you may experience with temporary sun blindness include:

  • an urge to squint or close your eyes
  • a painful burning sensation
  • tearing
  • temporary loss of vision
  • seeing bright spots or flashes
  • seeing dark spots or blotches
  • gritty sensation in the eyes
  • temporary color blindness

The following can cause or contribute to temporary sun blindness:

Exposure to the sun

About 95% of ultraviolet A (UVA) and 5% of ultraviolet B (UVB) from the sun reach the earth’s surface and can potentially damage the eyes, causing acute and chronic eye problems. The eyes are particularly sensitive to these rays; even short-term exposure can cause photokeratitis, also called sunburned eyes.

Also, staring directly at the sun (e.g., during a solar eclipse) can damage the retina (solar retinopathy), leading to temporary blindness. Over time, most people with solar retinopathy recover normal or near-normal vision.

UV rays reflected on surfaces

When sun rays hit surfaces like the shiny surface of a car, white sand, water, and snow, they get reflected off the surface and can cause sunburn in the eyes. Temporary blindness caused by the sun reflecting off the snow is called snow blindness.

Exposing the eyes to human-made sources of UV radiation

Sunlight is the natural source of UV radiation. But there are artificial sources like light from tanning booths and sun lamps, arc welding instruments, and laser light. Exposing your eyes to this light can damage structures in the eyes, leading to increased sensitivity to bright light from the sun.

Head trauma

Concussions and other head injuries can cause temporary blindness or sensitivity to light, including bright sunlight. According to a 2021 study, about 43% of participants experienced sensitivity to light after head trauma, including mild head trauma.

Underlying eye conditions

Having eye conditions like acute glaucoma, corneal abrasion, corneal inflammation (keratitis), or uveal tract inflammation (uveitis) can cause light sensitivity, contributing to temporary blindness when you go out in the sun.

Most cases of sun blindness are temporary and will pass with time. But, in rare cases, a person can experience permanent vision loss.

Sun blindness may also be associated with other eye conditions like cataracts, which can be attributed to too much sun exposure.

Other complications of chronic sun blindness include:

  • pain
  • eye irritation
  • anxiety around driving or going outside
  • increased risk of falls, injuries, and accidents
  • reduced quality of life

There is no standard treatment for sun blindness, as the symptoms usually improve within 24–72 hours. Your first step, if you experience sun blindness, should be to get out of the sun and remove contact lenses if you’re wearing any. Placing a cold cloth over your eyelids may provide some comfort.

A doctor may also recommend:

Talk with a doctor about your concerns. They may suggest you get screened for underlying eye conditions, like glaucoma, that could be contributing to the problem.

Here are some tips for preventing sun blindness:

  • Wear polarized sunglasses to block out the sun’s UV rays.
  • Wear hats or use umbrellas to supplement your sunglasses.
  • If you’re a welder, wear welding helmets and goggles when working.
  • Wear snow goggles designed to block UV rays when engaging in winter activities.
  • If you engage in water sports, consider using quality, wrap-around sunglasses with photochromic lenses.
  • Avoid indoor tanning beds.
  • If you want to watch a solar eclipse, ensure that you use approved eclipse glasses.
  • Avoid looking directly at the sun with regular sunglasses, binoculars, or the naked eye.

Why do I sometimes go temporarily blind?

Aside from sun exposure, there are several other reasons you may experience temporary loss of vision, including:

  • migraine
  • retinal tear
  • retinal detachment
  • blockage of the blood vessel supplying the retina

Can looking at the sun make you go blind?

Staring directly at the sun can cause severe damage to structures in your eyes, which can lead to blindness.

What is night blindness?

Night blindness, also called nyctalopia, is the inability to see at night or in a dimly lit room.

If you experience a vision issue like sensitivity to sunlight or loss of vision due to exposure to the sun, contact your eye doctor.

Aside from exposure to UV radiation from the sun, other things, like an underlying eye condition, can contribute to your symptoms. Your eye doctor will diagnose you properly and suggest ideal treatment options.