What Is Aphakia?

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Aphakia is when a person doesn't have the lens in one or both eyes. It can be congenital when people are born with it or acquired at any stage of life after a surgery or injury.

The lens is a transparent structure located behind the iris, and is vital for focusing on objects. Light enters the eye through the pupil, reaching the iris, which controls how much light enters the eye. It then reaches the lens, which will focus it on the retina. When the lens is absent, the person will have problems focusing and seeing things clearly.

aphakia
Paresh Padhi / EyeEm / Getty Image.

Aphakia Symptoms

When a person doesn't have a lens, they may experience the following:

  • Blurred vision
  • Farsightedness (hyperopia)
  • Difficult focusing objects
  • Decreasing focus when the distance from an object changes
  • Colors seem faded

Causes

Aphakia can occur due to injuries, cataracts, or genetics. Although it is rare, some infants can be born without lenses.

Genetics

The lens starts to develop in the third week of gestation. However, in some cases, it may not form or the body may absorb the lenses shortly after birth. Congenital aphakia is a rare anomaly, which can be associated with other ocular disorders. It can be subdivided into two forms: primary and secondary congenital aphakia:

  • Primary aphakia: Infants are born without a lens due to a mutation or problems during development. It can be associated with microphthalmia, absence of the iris, anterior segment aplasia, and sclerocornea (when the cornea blends with the sclera).
  • Secondary aphakia: This type of apakia occurs when the body absorbs the lens before birth. Some of those cases are associated with congenital rubella syndrome (caused by maternal infection with the rubella virus during pregnancy). 

Injury

Patients can also get aphakia after a globe injury or rupture. They may lose their lens during a severe injury, and this type of aphakia is known as traumatic aphakia.

Cataracts Surgery

Cataracts are the clouding of the lens of your eye. When a cataract clouds over the lens, your eye can’t focus light in the same way, leading to blurry vision or other vision loss. Most people wait until a cataract causes enough vision loss to be a problem to get surgery. Sometimes people need cataract surgery to see and treat other eye conditions, such as age-related changes in the retina or diabetic retinopathy. During the procedure the lens is removed and replaced with an artificial implant in most cases.

Although it is common in older adults, some infants can be born with congenital cataracts and will need surgery before the first month.

Diagnosis

In adults and older children, aphakia is diagnosed during a comprehensive eye exam. However, diagnosing congenital aphakia is often a challenge. The prenatal ultrasound diagnosis of aphakia is difficult and often requires a genetic study of the karyotype (a person's collection of chromosomes).

Treatment

Surgery is the most efficient way to treat aphakia in children and adults. Your doctor will insert an artificial intraocular lens (IOL) made of silicone, acrylic, or other plastic composition. They are also coated with a special material to help protect your eyes from the sun's ultraviolet (UV) rays.

Surgery for adults and infants may be different:

  • Surgery in adults: When the aphakia is caused by cataracts or an eye injury, the doctor will remove the damaged lens in surgery. The patient needs local anesthesia, and the surgery takes approximately one hour. If both eyes are damaged, the surgery is done in one eye at a time.
  • Surgery in babies: When infants are born with cataracts, the doctor often recommends surgery before the first month of life. The lens may not be replaced immediately, and the procedure to insert an artificial IOL is done after the first year of life. Children who undergo congenital cataract surgery need to schedule frequent eye exams during the first decade of life. After that, the eye exams should be done every one to two years throughout life.

Treatment of aphakia in children requires close attention. During the first years of life, the eye is still growing. Glasses or a contact lens must be fit quickly, so the visual pathway to the brain can start to form. An immature visual system in young children puts them at risk of developing amblyopia if visual input is defocused or unequal between the two eyes.

Glasses can cause image distortion, prismatic effects, anisometropia, and aniseikonia, resulting in a less than perfect vision. These effects are eliminated by using contact lenses, so contact lenses are preferred in treating aphakia in children.

Complications

It is uncommon, but patients may develop the following after surgery:

  • Aphakic glaucoma: Aphakia causes complex mechanical and biochemical changes in the vitreous (the clear gel that fills the space between the lens and the retina) and anterior segment structures, and the precise mechanism of glaucoma in aphakia is not fully understood. Those patients can develop aphakic glaucoma, a secondary type of condition that is more challenging to treat than primary glaucoma. People can also acquire glaucoma after cataract surgery, even years after the procedure. It happens due to changes in eye pressure, leading to damage to the optic nerve. 
  • Retinal detachment: After cataract surgery, retinal detachments occur in up to 3.6% of patients, and the risk is higher in young myopic patients. It happens when the retina detaches, causing eye floaters and a sensation that there is a curtain-like shadow over the eye.
  • Vitreous detachment: The vitreous is attached to the retina. Cataract surgery can lead to significant changes in the vitreous, including detaching it from the retina. 

Prognosis

The prognosis is hugely favorable if aphakia is fixed with surgery, especially when it happens due to cataracts. Most people with an IOL often don't have problems and don't need to change their lenses during their lifetime. However, it will also depend on an individual's ocular health. Therefore, it is crucial to have frequent eye exams. 

A Word From Verywell

Most aphakia cases are treated with surgery. However, patients should be aware that they will need regular eye exams to guarantee there are no other problems. When a child has congenital aphakia, parents play a crucial role in the treatment and vision development. They should be aware that successful treatment doesn't rely only on surgery but also regular eye exams and the correct use of eyeglasses and contact lenses. 

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