Hyperopia is a type of refractive error which causes people to experience blurred vision with objects close to them. However, they see distant objects clearly.
In hyperopia, the eye does not bend light appropriately to a single focus. Different people experience hyperopia differently. Some people will see both distant and close objects as blurred.
Children with mild or moderate hyperopia see both near and far objects. This is because they can squint very well as a result of the muscles and lenses in their eyes. As people grow older, they may not squint as well.
Also known as
- Structure (simple and pathologic) and functional
Simple hyperopia is due to the decreased converging power of cornea, lens, or media while pathologic may be caused by trauma or an eye disease such as cataracts.
Functional hyperopia is usually present at birth.
- Degree of refractive error
Range from low, moderate, and high.
- Role of accommodation to visual functioning
Includes facultative, absolute, and total.
- According to the outcome of non cycloplegic and cycloplegic refractions
Includes manifest and latent.
Causes and Risk Factors
Hyperopia is caused by the eyeball being too short. When the cornea has minimal curvature, farsightedness can result so that the light is not focused directly on the retina.
An individual is able to see when light rays bend as they travel through the cornea and the lens before focusing on the retina. Thus, the eye’s shape may prevent light from focusing on the retina.
The lens aging can also cause refractive errors.
Farsightedness affects both children and adults. It can also be inherited although some children outgrow it.
Drugs, such as cycloplegics, can also cause a transient hyperopia.
Signs & Symptoms
- Eye strain
- Blurry vision
- Aching eyes
- Trouble focusing on objects
Hyperopia is diagnosed by an eye care professional who does a comprehensive dilated examination. He will then prescribe treatment.
The eye care professional will conduct a standard vision test where the patient is required to read from a chart placed a little distance away. Once he/she determines that the patient is farsighted, he may conduct retinoscopy to see how light reflects off the retina.
This test can also determine whether a person is nearsighted or farsighted. The professional will use a phoropter to measure the amount of refractive error in the eyes.
Treatment is aimed at altering the way light enters the hyperopic eye. It is also directed towards permanently changing the shape of the cornea.
The most common medical treatment for hyperopia is the use of eyeglasses or contact lenses. The glasses and lenses alter how the light gains entry into the eyes. They allow patients to see objects that are close by. The glasses and lenses refocus light rays on the retina. They can also protect the patient's eyes from ultraviolet rays.
However, if the patient's vision is still not corrected by the prescribed glasses or lenses, they might need a new prescription. Hyperopia patients only need to wear glasses when they want to see objects that are near.
Hyperopia can be corrected through surgery. One popular surgical procedure is LASIK where the surgeon makes a flap on the top of the cornea. He then uses a laser to carve tissue inside the eye before moving the flap back into place.
Refractive surgery is however not recommended until the refractive error has stabilized and the eye has stopped growing. The stability and growth happens when people are in their 30s.
Young children with low to moderate hyperopia usually do not need intervention. An average person's eyes will change with age. Hyperopia patients aged 40 and above will need reading glasses.
If hyperopia is not treated, it may lead to esotropia (crossed eyes) or amblyopia (diminished vision in one or both eyes).