If you live in a sunny, and/or dry and dusty area, you’d be no stranger to the sight of a whitish-pinkish triangle growing over the usually transparent cornea of the eye. This condition, known as a pterygium, is a common finding all over the world, but is more frequently noted in latitudes closer to the equator and in people who spend a lot of time outdoors. You can read more about the risk factors of developing a pterygium here.
What are the common symptoms of a pterygium?
In many cases, a pterygium is just along for the ride, and sits quietly on your eye without causing too much fuss. However, for some people having the pterygium there at all is cause for fuss in itself – it’s not the most aesthetic sight. If you can look past the cosmetic issue, pterygia can often be ignored except for in the situations where they might:
- Appear red
- Become inflamed
- Become irritated
- Affect your vision
Can a pterygium cause double vision?
Also known as diplopia, double vision is a visual disturbance where you see two distinct images of the one object. This is separate from ghosting or blur, where you might get a faint shadowing of the outline of an object repeated behind the true image of the object.
Typically, diplopia happens because your two eyes are not quite looking in the same direction at the same time. For example, if you’re able to deliberately make yourself cross-eyed, you’ll notice that much of your surroundings are suddenly doubled (and probably not very comfortable to look at).
Diplopia arising from just one eye – monocular diplopia – is much rarer. But it can happen with a pterygium.
How pterygia affect vision
The cornea is the clear dome of tissue over the colored iris. It’s the first surface that bends light as it enters the eye (the second surface being the crystalline lens behind the iris), and contributes to focusing light onto the retina for sharp sight. When the focal point of incoming light doesn’t quite hit the retina right, you get refractive error.
If a pterygium has grown to the point where it can distort the shape and curvature of the cornea, it may induce a specific type of refractive error known as irregular astigmatism. Symptoms of astigmatism include:
- Haloes around lights
- Shadowing and ghosting
- Monocular diplopia
- Glare sensitivity and a “starburst” pattern around lights
- Blurred vision when viewing both distant and near objects
While regular astigmatism can typically be easily corrected with eyeglasses or contact lenses, irregular astigmatism is much trickier and is more likely to need special custom-made hard contact lenses or surgery to fix.
Though not common, the double vision from a pterygium may arise from this irregular astigmatism, and may be more pronounced when you turn your eye to the side away from the pterygium. For example, if you have a pterygium developing on your right eye, on the side closest to your nose (the left side of your right eye), when you look to the right, you may be more likely to notice the diplopia.
If your pterygium is causing problems
If you have a pterygium that is not just along for the ride and is, in fact, intent on making itself known through being red and irritated or interfering with your vision, you may consider pterygium surgery.
There are several different techniques of pterygium excision, with differing pros and cons. One significant complication of all techniques is the potential for pterygium recurrence, that is, the pterygium regrows after having successfully been removed. However, with the right surgical technique – and the right surgeon – you can minimize this risk.
Still unsure about whether your pterygium needs specialist attention? Reading this may help to clear it up for you.