Farsightedness (hyperopia) is a common vision defect that makes it difficult to focus on near objects. People with severe hyperopia can only focus on objects far away, or they cannot focus at all.
People with farsightedness can see objects farther away better than closer objects. It occurs when the eyeball or the lens is too short or the cornea is too flat.
Also known as longsightedness or hyperopia, it affects
It can either develop as the muscles weaken from approximately 40 years of age onwards, also known as presbyopia, or be present from birth.
The most common signs and symptoms of farsightedness:
- objects nearby appear blurry
- the person needs to squint or strain their eyes to see clearly
- a headache or discomfort occurs after prolonged reading or writing
- eyestrain develops, which burns or aches in or around the eyes
- the person cannot perceive depth effectively
Two parts of the human eye make it possible to focus.
The cornea: The clear, front part of the eye that receives and focuses light into the eye.
The lens: A transparent structure inside the eye that focuses light rays onto the retina.
The retina is a layer of nerves at the back of the eye that senses light and sends impulses through the optic nerve to the brain.
The optic nerve connects the eye to the brain and carries these focused light signals formed by the retina to the brain. The brain then interprets them as images.
The optimal shape for an eye is a perfectly smooth curvature of the cornea and lens. The length and shape of the eyeball also need to be optimal for perfect vision.
The cornea and the lens refract — or bend — the incoming light rays. When this happens, an image is focused sharply on the retina.
Farsightedness occurs when light does not refract properly. Instead, the light refracts through an uneven, less smooth cornea or lens. It is a type of refractive error. Refractive errors can also cause myopia, or shortsightedness, and astigmatism.
The light rays focus at a point behind the retina but not onto it due to the imperfect shape. They travel to the back of the retina before they have been bent properly by the lens and cornea, resulting in blurred vision when objects are closer.
People who are born with hyperopia may be able to focus on distant objects during childhood. However, eventually, it may become more difficult to focus, and even distant objects may not be clear.
In rare cases, farsightedness may result from:
- fovea hypoplasia, or macular hypoplasia — a rare medical condition involving the underdevelopment of the macula, a small area on the retina
Experts often link macular hypoplasia with albinism. They also believe farsightedness may be hereditary.
An optometrist can perform a standard eye exam to diagnose farsightedness.
Optometrists can assess vision, prescribe corrective lenses, and diagnose common eye issues. Alternatively, an ophthalmologist, or eye specialist, may carry out the exam if a more complex issue is suspected.
A person should have an eye exam if they are experiencing any of the above symptoms or reach 40 years of age without symptoms of farsightedness.
Younger children should also have vision testing at the following stages:
- at birth
- during their first year of life
- around 3.5 years
- around 5 years
A person who already wears corrective lenses will need more frequent exams to ensure their lens prescription remains appropriate.
Most eye conditions can be corrected successfully, but there is a risk of further complications if left untreated.
A complete eye test should check the following:
- ability to focus on near objects
- general eye health, to determine whether there are any eye conditions or physical abnormalities
- visual acuity, or sharpness, using a Snellen chart of letters that decrease in size dilation, or widening, of pupils
- side vision
- ocular motility, or eye movement
- the front of the eye
- retina and optic nerve
If a person wears prescription eyeglasses or contact lenses, they may need to wear them during the exam.
The eye specialist also checks for signs of eye conditions by shining a light into the person’s eyes and observing their reaction. They will look for disorders such as glaucoma or diabetic retinopathy.
Hyperopia treatment aims to help light focus correctly on the retina. Corrective lenses or refractive surgery may achieve this.
Most younger people with hyperopia do not need corrective lenses because they can compensate by focusing on nearer objects.
However, by the age of 40, when the lenses are less flexible, most people with longsightedness need corrective lenses because their lenses are not able to compensate.
There are two primary types of corrective lenses:
- Eyeglasses: These may include bifocals, trifocals, and standard reading glasses.
- Contact lenses: Various types of contact lenses are available, with differing levels of softness and intended duration of wear.
Doctors normally use refractive surgery for nearsightedness, or myopia, but it can also treat hyperopia.
- Laser-assisted in situ keratomileusis (LASIK): A laser or microkeratome reshapes the center of the cornea into a steeper dome.
- Laser epithelial keratomileusis (LASEK): A laser reshapes the outer edges of the cornea into a steeper curvature.
- Photorefractive keratectomy (PRK): The surgeon removes the outer layer of the cornea and a similar procedure to the LASEK is carried out. The outer layer then grows back over about 10 days.
- Conductive keratoplasty (CK): Doctors reshape the cornea using a radiofrequency-emitting probe placed at its edge, which causes slight shrinkage to the peripheral collagen.
LASIK, LASEK, and PRK reshape the cornea to steepen the peripheral cornea. This increases the overall power of the cornea.
Both the LASIK and LASEK procedures create a flap made from the epithelium — the top-most layer of the eye — which can re-cover the treated eye tissue. LASIK creates this flap using a laser or microkeratome, whereas LASEK creates the flap using alcohol. PRK removes the flap using alcohol but does not re-cover the eye tissue with the flap.
PRK and LASIK are popular surgeries, while doctors rarely use LASEK or CK.
Laser surgery may not be suitable for those who:
- have a constantly changing corrective lens prescription
- have diabetes
- are pregnant or breastfeeding
- have a weakened immune system
- have other eye issues, such as glaucoma or cataracts
Risks of laser surgery
All surgical procedures have some risks.
The most common temporary side effects after LASIK include:
- hazy or blurry vision
- difficulty with night vision
- itchy or dry eyes
- halos or glares
- light sensitivity
- discomfort or pain
- small pink or red patches on the white of the eye
Rarely, laser surgery may result in the following complications:
- Worse post-operative vision: The vision may be worse than before if the surgeon misjudges how much tissue to remove from the cornea.
- Epithelial in-growth: The surface of the cornea starts growing into the cornea itself, leading to further vision problems. This may require additional surgery.
- Ectasia: The cornea becomes too thin, vision worsens, and there is a risk of total vision loss.
- Microbial keratitis: This is an infection of the cornea.
An older 2005 study found the risk of complication following LASIK surgery to be as follows:
- 0.6% chance of a correction error
- 1.3% chance of epithelial in-growth
- 0.2% chance of ectasia
- 0.16% chance of microbial keratitis
The risk factors may be similar in LASEK and PRK surgery.
Possible complications of hyperopia
Complications in adults are rare. The condition worsens with age, but stronger glasses usually enable the person to see properly.
Complications only tend to occur when hyperopia goes untreated in children.
Strabismus, or squint: The eyes are not properly aligned, and focus on different things. This may affect depth perception and make it difficult to determine how far away objects are. The other eye may become weakened, leading to amblyopia.
Amblyopia: One or both eyes becomes dominant, usually due to
Both complications are treatable.
Wearing a patch over the stronger eye can encourage the brain to take more notice of the weaker eye. This strengthens the eye muscles.
Prescription eyeglasses may help align the eyes and provide the clarity needed to correctly develop the visual pathway.
In severe cases, a person may need surgery to realign the eyes and strengthen the eye muscles.
Adults who develop hyperopia and do not get corrective lenses may find that their quality of life is undermined and may have an eye that never sees 20/20.
Longsightedness is thought to be hereditary, caused by misshapen eyes. Farsightedness may worsen after the age of 40, but it is easily treatable with corrective lenses or surgery.