What is Aphakia?
Eye contains a crystalline transparent biconvex lens which focuses the image on the retina. It is this lens which offers vision of the world around us. Aphakia is a medical condition where the lens is removed from an eye due to cataract operation or during an injury. A person with aphakia has problems in focusing on the object and has difficulty in seeing. (Aphakia means a=without; phakos= lens). Aphakia is mainly observed in adults after the age of 40 years and is rarely seen in the newborns.
Characteristics of Aphakia
- People with aphakia have problems with vision. They suffer from hypermetropia (long sightedness).
- Loss of accommodation of vision. In this case, the eye is not able to focus on the object when the object changes its position far and near.
- Deep anterior chamber due to absence of lens.
- Changes in color vision:
- The colors become very strong as the lens is absent which allows more sunlight to enter the eye.
- Both erythropsia and cyanopsia symptoms can occur in people after cataract operation but these are temporary. Erythropsia is a condition in which the objects appear reddish in colour. Cyanopsia happens where everything appears to have a blue tint. Both these condition occur since there is entry of infrared and ultraviolet rays due to absence of the lens.
Causes and Risk Factors of Aphakia
The causes and risk factors for aphakia include:
The presence of cataract makes the lens cloudy due to which it cannot refract light and the affected person cannot see. The lens becomes milky in appearance due to clumping of the proteins because of the increased age. In rare cases, babies are born with cataract which is either a genetic defect or caused due to diseases such as chickenpox. Such lens is removed surgically resulting in aphakia. Aphakia due to cataract is most common.
It is a very rare condition where babies are born without lens in their eyes. This is called as congential aphakia and is of two types: primary aphakia and secondary aphakia.
Primary aphakia is of severe form where babies with developmental problems or genetic mutation are born without lenses. While secondary aphakia is of less severe form where, babies have lens however it gets absorbed or detached before birth. This type of aphakia also results due to infection with rubella virus.
Posterior dislocation of lens in vitreous causes optical aphakia
Aphakia due to Injury:
If injuries or trauma occur to the face, then they can damage lens or cause it to get detached and push it inside the eye.
Absorption of Lens Matter occurs rarely after trauma in children
Heredity Causes of Aphakia:
There are few heritable disorders which cause dislocation of lens:
- Marfan’s syndrome
- Weill-marchesani syndrome
Diagnosis of Aphakia
An ophthalmologist examines the eye for presence of cataract in the eye lens. The doctor also examines the iris, cornea, fundus and retina. The distance, near vision and refraction are determined.
The doctor looks for different signs such as:
- Jet black pupil
- The black ring around the iris
- Iridodonesis where the iris appears loose since it lacks the support of the lens
- The presence of small hypermetropic fundus.
For a person with no lens, it further confirms aphakia.
Treatment of Aphakia
The absence of the lens makes the vision farsighted. Although, spectacles and contact lens can be used, they have a number of disadvantages. Hence they are not preferred. The treatment method includes:
- Intraocular lens (IOL) implantation is popular and a preferred method where an artificial lens is used. It is also called as pseudophakia. These lens help to adjust the focus of vision to different lengths. The patient gets advantage of normal vision. There are fewer disadvantages and generally outcome is good.
- Another method of treatment is refractive surgery. This is a comparatively recent method for treatment for aphakia. This includes:
- Hyperopic Lasik
- Keratophakia is a procedure where corneal tissue from a donor is frozen, shaped and placed into the cornea of the patient.
- Epikeratophakia is the refractive surgical correction procedure of aphakia. It involves transplantation of donor’s cornea to the anterior surface of patient’s cornea.
- In case of babies with aphakia, treatment involves use of special contact lenses which are safe for baby since they sleep wearing it and can be used for extended duration. In addition, babies may need eye drops or eye patch or both so that they get used to these lens. It is advised to get childhood cataracts treated immediately to avoid amblyopia.
Complications of Aphakia
Person suffering from aphakia should take treatment to avoid these complications:
- Detachment of vitreous chamber
- In case of infants, if aphakia is not treated, it leads to amblyopia (or lazy eye). It is a disorder of eye where eye and brain do not work together. The eye fails to attain normal vision.
Aphakia is an ophthalmic problem which needs to be treated. Opting for recent methods such as use of artificial lens and refractive surgery will improve the life of an aphakia patient.
- “Aphakia: Causes, Symptoms, Diagnosis, and Treatment.” American Academy of Ophthalmology. https://www.aao.org/eye-health/diseases/what-is-aphakia
- “Aphakia.” National Center for Biotechnology Information. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5477024/