All about Hypermetropia, Hyperopia or Farsightedness: Definition, Causes, Symptoms, Diagnosis, Complications, and Treatment.
What is Hypermetropia (Farsightedness)?
Also known as hyperopia, hypermetropia or farsightedness is a type of refractive error in which a person can see distant objects easily, but have difficulty seeing objects that are up close. If the amount of hyperopia is high, it will be difficult to focus on far objects too. It is a common vision problem that has affected about 25% of the world population.
Children with mild to moderate hypermetropia can see both far and close objects clearly without refractive correction, but with the extra effort of ocular muscles and eye lenses. As a consequence, there will be a risk of squint and other ocular disorders.
Farsightedness Causes
Hypermetropia occurs when the cornea (clear window of the eye) is too flat or when the eye is shorter than normal size. Due to flat cornea or shorter eyeball, the rays of light entering the eye get focused outside the retina instead of on it. As a result, you can see distant objects somewhat clearly but near objects appear blurred.
Like in myopia, genetic factor plays an important role in hyperopia. But it is difficult to find out the exact amount of farsightedness in children as their flexible lenses are accommodating to a maximum extent to make a clear vision by refracting the light rays to focus on the retina.
Usually, most children are hyperopic of a small amount, yet they do not experience blurry vision. They become emmetropic (eye without refractive error) as the eye grows and become longer.
Sometimes hypermetropia is confused with presbyopia. Presbyopia also causes blurry vision for near but for different reasons.
Symptoms of Hyperopia
During childhood, the symptom of farsightedness is not prominent as the eyes are good at the accommodation. However, with growing age, the age-related changes in the lens make the process of accommodation less flexible, and the symptoms of hypermetropia eventually appear. The most common symptoms of hyperopia include:
- blurry vision for near objects (maybe for distance)
- squinting of eyes to see clearly (crossed eyes or an accommodative esotropia in children)
- headache
- eye strain
- eye fatigue when performing near tasks, such as reading, computer work for a prolonged interval
If you are experiencing any of these symptoms you may need an eye exam and hyperopia correction in the form of eyeglasses or contact lenses. Also, if you are wearing hyperopic correction and if you have these symptoms, you may need a new prescription.
Hypermetropia Diagnosis
Common vision screening tests, like those done in schools, usually don’t detect hyperopia. For proper diagnosis of the amount of hyperopia and the types of hypermetropia, a comprehensive optometric examination is necessary. The comprehensive tests include visual acuity tests both for near and distance and a refraction test.
Sometimes, it is necessary to perform wet refraction (cycloplegic refraction) to rule out the amount of latent hyperopia. If needed, your optometrist can explain to you the treatment options.
Complications of Hyperopia
If left untreated, hyperopia can be associated with severe problems, such as:
Lazy eye (amblyopia)
Hypermetropia is a major cause of refractive amblyopia in children. If farsightedness is not diagnosed and treated at an early age of life, it may lead to permanently reduced vision. So, proper refractive correction in combination with other lazy eye therapy help to regain and maintain good vision in hyperopic eyes.
Crossed eyes (esotropia)
When hyperopia is left untreated, the ocular muscles and eye lens continuously use extra force to make objects clear. This prolonged stress on ocular muscles and lens contributes to cross eyes ie. esotropia. Timely prescribed eyeglasses help to reduce the amount of esotropia and maintain a clear vision for all distances.
Reduced quality of life
Uncorrected farsightedness affects the quality of life in one way or another. It starts with difficulty in developing learning skills as the child can’t see letters clearly. So, the child starts to focus mostly on distance tasks and it limits the skill development and learning habit of the kid.
Treatment of Hypermetropia
Your eyes may be able to compensate for the mild cases of hypermetropia without correction. Similarly, treatment may not always be necessary for young children as the natural crystalline lenses inside the eyes are capable to compensate for the farsightedness of a small amount.
You may need prescription lenses to improve near vision as you age and the lenses inside the eyes become less flexible. Hyperopia is corrected with eyeglasses or contact lenses to focus the divergent beam of light on the retina.
Your need to wear a convex lens (plus lens) and contact lens of plus power to neutralize the effect of farsightedness. The wearing time duration might vary based on the amount and type of hypermetropia. You may need to wear corrected plus power when reading, working on a computer, or all the time as directed by your optometrist.
The available options to regain clear vision in hyperopia includes eyeglasses, contact lenses, and refractive surgeries.
Eyeglasses for hyperopia
Eyeglasses are the primary choice for farsightedness correction. The amount of hypermetropia will determine the type of lenses you need to wear. If you have a small amount of farsightedness, you wear eyeglasses for near activities, like reading, writing, using mobile phones, and a computer. If you are very farsighted, you have to use eyeglasses all the time.
Eyeglasses for hyperopia are available as single vision lenses, bifocal or progressive lenses based on the age and difficulty for near vision along with a blurry distant vision.
High index lenses (thinner, and lighter lenses) and lenses with anti-reflection coating are good choices for farsightedness. Likewise, photochromic lenses protect your eyes from UV rays if you have to spend time working outdoors.
Contact lenses
Contact lenses provide a clear vision with a wider field of view than eyeglasses. So, for those who are able to take proper care of contact lenses and who wish to get rid of eyeglasses, contacts are good options. You may opt for soft spherical lenses, soft toric contact lenses, or multifocal lenses according to the type of hyperopia in your eyes.
Consult your optometrist for the pros and cons of contact lenses for hypermetropia and what might be best for you.
Refractive surgery for hypermetropia
Hyperopia surgery removes the need for eyeglasses or contact lenses. A refractive surgeon uses an excimer laser to reshape the cornea (anterior transparent layer of the eye) and neutralize (or reduce) the amount of farsightedness.
In the majority of cases, you need not use eyeglasses or contacts after hypermetropic refractive surgery. In some cases, however, you may need to use eyeglasses and contact lenses of minimum plus power. The following types of refractive surgery are common in hypermetropia correction:
- Photorefractive keratectomy (PRK)
- Laser-assisted in situ keratomileusis (LASIK)
- Laser-assisted subepithelial keratectomy (LASEK)
Consult with your ophthalmologist to know about the possible side effects of this irreversible procedure.
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