In 2025, our understanding of eye health continues to evolve, and new research sheds light on lesser-known eye conditions that can affect people's vision. While many are familiar with common eye conditions like nearsightedness or cataracts, there are less common conditions that can have a significant impact on your sight. Here are five lesser-known eye conditions to be aware of.
1) Photophobia: Sensitivity to Light
Photophobia, or light sensitivity, is an eye condition where your eyes become excessively sensitive to light, causing discomfort or even pain. Photophobia can make normal, everyday exposure to light—whether sunlight, fluorescent lights, or even the light from a computer screen—feel overwhelming.
Photophobia is not necessarily a problem with the eyes themselves. The discomfort typically comes from how the brain processes light signals from the eyes. It can be linked to various underlying conditions, including migraines, dry eyes, and certain neurological conditions.
What are the symptoms of photophobia?
- Discomfort or pain when exposed to bright light
- Squinting, tearing, or a desire to cover the eyes when in well-lit environments
- Headaches or migraines triggered by light exposure
- Difficulty seeing clearly in bright environments
What is the treatment or ways to reduce symptoms of photophobia?
- Sunglasses: Wearing sunglasses with UV protection when outdoors can help reduce light sensitivity.
- Tinted lenses: Specialized lenses that filter light can provide relief.
- Adjust lighting: Using softer, dimmer lighting indoors can help lessen discomfort.
- Addressing underlying conditions: Treating associated conditions like migraines or dry eye may reduce photophobia.
How common is photophobia?
Photophobia is not rare and can occur in individuals with conditions such as migraines or concussion, but it’s often underreported.
Photophobia can develop at any age, but it’s commonly reported in adolescents and adults who suffer from conditions like migraines or eye strain. Photophobia can also be a temporary effect from conditions like pink eye or a scratched cornea.
2) Heterochromia: Two Different Colored Eyes
Heterochromia is a rare eye condition where an individual has two differently colored eyes or two different colored sections of the same eye. There are two types of heterochromia:
- Complete heterochromia (two different colored eyes)
- Sectoral (or partial) heterochromia (one eye has two different colors)
What are the symptoms of heterochromia?
- One eye is a different color from the other (in complete heterochromia).
- A section of one eye has a different color from the rest of the eye (in sectoral heterochromia).
Heterochromia is typically harmless and does not require treatment. However, if it develops suddenly or is associated with other symptoms like vision problems, an eye doctor may need to investigate further.
How common is heterochromia?
Heterochromia is extremely rare. It occurs in only about 1 in 1,000 people, with sectoral heterochromia being more common than complete heterochromia.
When does heterochromia typically appear?
The condition is often congenital (present at birth), but it can develop later in life due to trauma, disease, or medication side effects.
3) Kaleidoscope Vision: Seeing Through a Distorted Lens
Kaleidoscope vision refers to the visual distortion where a person sees their world as fragmented or colorful in odd patterns. Kaleidoscope vision often accompanies migraines or certain eye conditions, such as retinal disorders.
This eye condition doesn’t mean the person is seeing literal kaleidoscope patterns, but rather that the brain is misinterpreting visual signals due to a disruption in the visual system.
What are the symptoms of kaleidoscope vision?
- Distorted or fragmented vision, similar to looking through a kaleidoscope
- Seeing flashes of light or zigzag patterns
- Difficulty focusing
- Temporary blindness or visual impairment during episodes
What is the treatment or ways to reduce symptoms of kaleidoscope vision?
- Medication: For those whose kaleidoscope vision is associated with migraines, medications to prevent or treat migraines can help.
- Rest: Often, resting in a dark, quiet room can alleviate the visual disturbances.
- Avoiding triggers: Identifying and avoiding triggers, such as stress, certain foods, or bright lights, can help reduce the frequency of episodes.
Kaleidoscope vision is often associated with migraines and can affect up to 25% of people who experience migraines. It is relatively rare for those without a history of migraines. However, if kaleidoscope vision has suddenly appeared with no prior history, it could be a sign of something more serious like a brain injury or stroke.
Kaleidoscope vision most often appears in individuals between the ages of 18 and 45, particularly in those who have a history of migraines.
4) Polycoria: Multiple Pupils in One Eye
Polycoria is an extremely rare eye condition where an individual has more than one pupil in the same eye. Polycoria can cause blurry vision and sensitivity to light due to the irregular shape and function of the eye. The extra pupils often do not function properly, leading to distorted or impaired vision.
What are the symptoms of polycoria?
- Presence of more than one visible pupil in one eye
- Blurry or distorted vision
- Light sensitivity and difficulty adjusting to changes in light
What is the treatment or ways to reduce symptoms?
There is no direct treatment for polycoria, but individuals can manage the condition by:
- Using sunglasses: To reduce light sensitivity
- Eyeglasses: Prescription lenses can help improve visual acuity if polycoria affects vision clarity.
How common is polycoria?
Polycoria is an exceedingly rare condition—there are fewer than 100 documented instances worldwide.
Polycoria is usually present from birth. However, it can sometimes develop after trauma to the eye or as part of certain syndromes.
5) Achromatopsia: Severe Color Blindness
Achromatopsia is a rare genetic condition affecting the color-detecting cells (cones) in the eye. With achromatopsia, a person is unable to perceive any color and only sees in shades of gray, black, and white. It is different from typical color blindness in that it often involves sensitivity to light and reduced visual sharpness.
What are the symptoms of achromatopsia?
- Total color blindness
- Severe light sensitivity (photophobia)
- Reduced visual sharpness or acuity
- Nystagmus (involuntary eye movement)
What is the treatment or ways to reduce symptoms of achromatopsia?
There is no cure for achromatopsia, but management strategies include:
- Special tinted lenses: These can help manage light sensitivity.
- Low vision aids: Magnifiers and other devices can help individuals with reduced visual acuity.
How common is achromatopsia?
Achromatopsia is rare, affecting approximately 1 in 30,000 people globally, and is typically present from birth.
Conclusion
These lesser-known eye conditions may not be very common but they can have a significant impact on a person’s quality of life. Understanding their symptoms, causes, and available treatments is essential for better managing and living with these rare eye conditions.
If you or someone you know is experiencing any unusual changes in vision, it's always a good idea to consult an eye care professional for a comprehensive evaluation. Your eye health journey can be simpler with a vision insurance plan that offers comprehensive coverage. The VSP® Individual Plan Selector is a quick and easy way to find the right vision plan and connect you to their large network of vision providers.
Information received through VSP Vision Care’s social media channels is for informational purposes only and does not constitute medical advice, medical recommendations, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.
Reviewed by Dr. Valerie Sheety-Pilon:
Dr. Valerie Sheety-Pilon is Vice President of Clinical and Medical Affairs at VSP Vison Care where she helps drive strategic initiatives aimed at raising awareness about vision, eye health and its connection to overall wellness, while providing insight into medical advancements that seek to benefit patient care. She also provides oversight of VSP programs to address gaps in care for some of the most high-risk populations, including those living with diabetes.
With more than two decades of experience as a Doctor of Optometry, Dr. Sheety-Pilon has dedicated much of her time to clinical research across numerous ophthalmic subspecialties and has an established history of helping patients through novel therapeutic agents and clinical adoption of transformative technology in the areas of digital health, pharmaceuticals, and medical devices.
Prior to joining VSP Vision in 2019, Dr. Sheety-Pilon served as Adjunct Clinical Professor at Illinois College of Optometry, held various executive positions within the eye health industry, and has extensive experience managing and practicing within an ophthalmology and optometry practice.
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