What is the optical defect in aphakia?

Having good eyesight without the need for additional devices or instruments is indeed a blessing. Having an eye helps humans to see the many beauties and wonders of the world. It also helps humans to survive and learn many things that could enrich their life both mentally and physically. However, there are health conditions or diseases that can affect the eye, causing visual disturbances ranging from mild to severe. Through this DoctorOnCall’s article, we will learn about an eye condition that can affect the eye vision known as aphakia and learn a bit about the optical defect associated with this condition.

Lens has an oval shape and a clear portion of the eye that’s normally seen in front of irises, but which can be colored as well. In order to change its shape and curvature, the lens is able to contract or relax. This helps the light to be directed and focused on the retina in a proper way. Think of it like a camera lens. With a camera lens in place, you can take clear images focusing on an object wherever it is or near to the camera.  As a matter of fact, if there’s no lens in the eye that is working well, it can cause problems with vision.

Aphakia is an eye condition where the person does not have a lens in their eyes. In other words, a person with aphakia is said to be missing the lens inside the eyes in one or both of the eyes. Simply said, without the lens, a person’s vision is usually disturbed. This shows that lenses play a great role in maintaining good eye vision.

Aphakia in most cases are caused by cataract surgery. In some cases, it may be from an accident or trauma that causes the lens to be misplaced or damaged. Some may even get aphakia since they are little as a result of genetic or congenital defect but this is considered rare. The term aphakia may be confused with pseudophakia when it is associated with cataract surgery. While aphakia is a condition of missing lens in the eyes, pseudophakia is referred to as the additional artificial lens called the intraocular lens (IOL) inserted in the eyes during cataract surgery.

It is necessary to spot aphakia signs. Knowing the signs can help a person get proper treatment to help improve their vision. This is especially important for babies and children as aphakia that goes untreated may lead to amblyopia (lazy eye) that leads to vision loss. Signs of aphakia includes:

Blurred vision

Inability to see objects close-up or farther away

Problems seeing brightness of colours as colours may seem faded

Iridodonesis, a condition where the iris is jiggly or trembles due to the lack of support caused by the missing lens or damaged one

Aphakia is treatable in both children and adults. A standard eye exam by optometrist can help detect this condition. You may be referred to an ophthalmologist for further investigation and examination before a treatment plan is laid out. The recommended treatment is usually a surgery by replacing the missing or damaged lens with an IOL. In some cases, special contact lenses may be recommended for babies that are too young for surgery. A child can go through surgery for lens replacement as young as 2 years old. For cases with both eyes with aphakia, aphakic glasses may be used but currently is rarely used as the lenses are thick and heavy making it uncomfortable.

Listed below are lenses used for treatment of aphakia:

IOL- Artisan lens that is made with Polymethylmethacrylate (PMMA). Other IOL materials are silicone and acrylic.

Contact lenses- Silicone elastomer and RGP (rigid gas permeable) contact lenses. Available as rigid or soft.

The question now is, what is the optical defect in aphakia? There are few optical defects that need to be known by both optometrist and ophthalmologist before treating them. This includes false depth vision due lens accommodation problems, change in colour vision, more chances for hypermetropia (far-sightedness) and image aberrations. It may also lead to inaccurate spectacle prescription due to the faulty measurement.

It can be concluded that aphakia is much more than just missing lenses. It can leave a person with vision problems when going untreated. Most people recover from aphakia following treatment with no significant complications. Note that aphakia in children may need to be periodically adjusted due to rapid changes in ocular shape and refractive error. Although it may not lead to life-threatening conditions, aphakia can certainly lead to poor quality of life especially in children and babies. It is important to get regular eye examination at least once a year by an optometrist or ophthalmologist.