REFRACTIVE ERRORS
WHAT ARE REFRACTIVE ERRORS?
Refractive errors mean that the shape of an eye does not bend light correctly upon entering the eye resulting in blurred images. This can be easily addressed with either glasses or contacts. The main refractive errors are myopia, hyperopia, astigmatism, and presbyopia.
MYOPIA
Myopia or nearsightedness makes far objects look blurry. This happens either when there are problems with the shape of the cornea or the lens. It also happens when the eyeball grows too long from front to back. All these conditions make the light focus in front of the retina while the normal eye has light focusing on the retina.
Myopia usually starts at an early age between 6 and 14 years old. In case of severe myopia, the risk of other eye conditions increases.
HYPEROPIA
Hyperopia or farsightedness makes nearby objects look blurry. As opposite to myopia, hypertropia happens when the eyeball grows too short from front to back. It can also happen if there are problems with the shape of the cornea or lens. With all these issues, the light focuses behind the retina instead of on the retina.
Hyperopia appears most of the time at birth.
ASTIGMATISM
Astigmatism can make nearby or far away objects look blurry or distorted. Like myopia and hyperopia, this condition happens when the cornea or lens has a different shape than normal. It makes light going to a different position when it enters the eye.
Astigmatism is usually accompanied by another refractive error such as myopia or hyperopia. People are either born with it or develop it in their youth.
PRESBYOPIA
Presbyopia touches middle-aged and older adults. It makes it harder to see things nearby. Aging changes the lens in the eyes, it becomes less flexible, and light is not focusing properly on the retina.
Presbyopia touches everyone. It usually happens after 45 years old.
SYMPTOMS
- Blurry vision
- Double vision
- Hazy vision
- Seeing a glare or halo around bright lights
- Squinting
- Headaches
- Sore or tired eyes
- Trouble focusing when reading or looking at a computer
Sometimes patients do not notice the symptoms of a refractive error. That is why it is important to a get regular eye exam. It allows patients to have the best vision possible and fix symptoms such as not being able to focus. This kind of symptoms can feel natural.
When a patient is diagnosed with a refractive error, he or she should keep having regular eye exams as refractive errors evolve and prescriptions need to be updated.
DIAGNOSIS
Your eye doctor checks for refractive errors during a comprehensive eye exam. Your doctor simply asks you to read letter charts and measures the results to determine if corrective eyeglasses and contact lenses are needed.
TREATMENT
Treatment includes eyeglasses and contact lenses. Sometimes laser surgery (LASIK) can be performed to change the shape of the cornea and fix the refractive error.