Aphakia Meaning: Causes, Symptoms, Treatment & Lens Options

Aphakia breaks down into the prefix ‘A’ and Latin root ‘Phako,’ where 

Prefix A means ‘without’ or ‘lack of,’ and

‘Phako’ translates to the ‘lens’ of the eye. 

Thereby Aphakia is an ocular manifestation that translates to “without the lens.” Individuals with aphakia have either one or both lenses missing since birth.  It can also manifest in the later half of the life when, 

• The lens is dislocated
• The lens is underdeveloped

Types of Aphakia 

Do you know? Around 6.1 million (5.1%) population in the world either have pseudophakia or aphakia. There is not only a single cause or type, as agents and factors for such may vary. So we begin with the types of aphakia. 

1. Congenital Aphakia  

This is a rare condition where an individual is born without a lens

• Primary congenital aphakia results from the failed induction of the lens placode is itself absent and therefore the lens is absent. 
• Secondary aphakia is a condition where the lens placode has developed but has been resorbed before birth. In such a case, the lens remnants such as the lens capsule are present. 

2. Surgical Aphakia: 

Aphakia is the absence of the lens on either or both eyes after one undergoes its surgical removal. It can happen post-cataract or removal of any perforating wound or ulcer via a congenital anomaly.

3. Optical aphakia 

Optical aphakia is also known as post-dislocation aphakia. In aphakia, this lens is gone. This can happen for several reasons:

• Birth defects: The lens might not form properly.
• Injury: The lens can get dislodged or damaged.

This condition can arise from trauma or underlying systemic diseases that weaken the zonules. The fibers that hold the lens in place are not functioning and thereby the lens is absent. 

What are the different types of Lens Dislocation?

In cases of optical aphakia, lens dislocation can be classified based on its severity and direction:

• Superior Temporal Dislocation: Commonly observed in conditions like Marfan syndrome, where the lens shifts upward and toward the temple side of the eye.
• Complete Subluxation: The lens may be partially or fully displaced from its normal position, which can occur in various genetic disorders or as a result of trauma.

Dislocation of the lens (Ectopia Lentis): Simplex vs. Et Pupillae

Common Genetic Mutations Associated with Aphakia

Aphakia can be genetic, due to pre-natal development issues of the lens in the mother's womb. It can also manifest as the repercussions of cataract surgery. We will discuss what will happen to our eyes, when our eyes lose the natural lens, for a better understanding of the topic.  

1. Marfan Syndrome: 

Marfan syndrome is a genetic disorder that causes dislocation of the lens (optical aphakia). Individuals born under this condition are muted in the fibrillin-1 gene, which causes the lens to shift and move in a superior-temporal direction. Research mentions that  65% of individuals with Marfan syndrome are already experiencing this problem with ectopia lentis (lens dislocation). 

2. Homocystinuria: 

This metabolic disorder can also lead to lens subluxation and progressive vision issues. It is associated with similar ocular manifestations as Marfan syndrome but may involve different mechanisms of lens dislocation.

3. Weill-Marchesani Syndrome: 

Weill-Marchesani Syndrome is a rare genetic disorder that can cause optical aphakia. It sounds similar to Marfan Syndrome but it is different. Though both impact the connective tissues, this Syndrome especially causes, 

• The lens is unusually small and round (microspherophakia).
• The structures holding the lens in place weaken.
• Propel the downward displacement of the lens.

4. FOXE3 Gene Mutations  

These aphakia are most prevalent in Hispanic populations (8.2%), 4.8% in African Descent, and 9.9% in Chinese Americans as the data suggests. It is also known as homozygous nonsense mutations. We might not be aware but children born from marriage between close relatives in consanguineous communities also tend to develop congenital primary aphakia. 

What are the optic complications in aphakic eyes? 

The lens no longer separates the aqueous humor from the vitreous humor if there is an aphakia condition diagnosed in an individual. The lens usually contributes +16 D power to the eyes and if there is no or damaged lens, then the dioptric apparatus of the eyes changes. 

Image by Insight Ophthalmology 

We only have the cornea left with the single refractive surfaces. Thereby handed operation of the eye, so the power of the eye now will be reduced.  Thereby, 

• Eyes will be highly hypermetropic 
• Loss of a significant amount of its focusing power 
• Vitreous loss and degeneration
• Visual Disturbances 
• Changes in Color Perception 

Not only the above symptoms but when the eye loses its natural lens, there is an increased risk of the eyes. It can suffer from other eye diseases with its progressive aphakia like, 

• Secondary glaucoma 
• Retinal detachment 
• Corneal decompensation (Damage to Corneal epithelium)
• Anisometropia (Unequal focus between two eyes)  
• Astigmatism
• posterior capsule opacification (PCO); secondary cataract. 

If a person has surgical aphakia, the chances of astigmatism are high. There are two conditions here, 

• A sutureless surgery incision will flatten the meridian causing “Against The Rule Astigmatism” of 1-1.5 Diopter.  
• A SICS/ECCE surgery uses a suture to steepen the meridian, which can cause “With the Rule Astigmatism” of up to 3 Diopters. 

Symptoms Aphakia

The symptoms are very obvious. Imagine what will happen to your eyes, if you don’t have the lens for refraction of image. The eyes are out of focus and you start to see blurred images, hues, or vision distortions.  

1. The patient has defective vision (both far and near) due to their high hypermetropia and defective accommodation. 
2. Erythropsia and Cyanopsia: Occurs due to excessive entry of UV and Infrared rays in the absence of the crystalline lens. You get different hues in the image, red hues (erythropsia) and bluish hues (cyanopsia). 
3. Limbal scar/Incision: based on surgery 
4. Anterior Chamber depth: Deep Anterior chamber 
5. Iridodonesis: tremulousness of the iris 
6. Changes in color perception, where colors may appear faded.

Signs of Examination in Aphakia

Pupil: Jet Black un color

Purkinje image test: Only 2 Purkinje images 

Fundus examination: Small Hypermetropic disc

In normal eyes, there are about 4 Purkinje images that come consecutively from the anterior and posterior surface of the cornea and lens. When the entire lens is gone, only 2 Purkinje images are perceived. 

How can I correct my aphakia? 

Aphakiac obstacles are the most common method of treating aphakia in the past. Today, when the surgery is not done and the patient cannot wear contact lenses, still there is the practice of using those spectacles. 

Image magnification in aphakia is a significant concern when correcting vision with spectacles. Aphakic spectacles can magnify images by approximately 30% to 33%.  (It is around 1/3rd more magnified) and enhanced performance is seen in the Snellen test. 

The Aphakic glasses prescription can vary from patient to patient. In most cases, diplopia may arise.  

Issues of aphakic spectacles

1. Optical aberrations

The design of aphakic lenses can introduce various optical aberrations, such as radial astigmatism, spherical aberration, and chromatic aberration.  

• Chromatic aberrations- the issues of the eyes focus all lights on a single point. Manifests itself as fringes of colors at the boundaries of images.   
• Spherical aberrations: Central rays (axial rays) are coming at focus at a point and par axial rays are bending at the usual focus point. Image distortions are common with this. 

Real life becomes much more challenging with spherical aberrations. Even straight lines seem to curve with these, and disturbing illusions like doors appearing curved inwards and narrow spaces to pass by occur. 

Aphakic patients can prevent this by always putting their heads straight and looking through the central point. 

2. Visual disturbances 

The Jack-in-the-Box phenomenon and roving ring scotoma are visual disturbances commonly experienced by individuals with aphakia. 

Whenever a patient is in the room the area with clear vision will be surrounded by fog and even the objects outside the peripheral vision appear blurry, thereby needing extra period for adjustments. 

Roving Ring Scotoma is when objects disappear and then reappear as they cross the edge of the lens. The unpredictable nature of visual distortions can also lead to anxiety.

3. Cosmetic Problems and Adaptation Issues

Aphakic glasses are quite heavy and keep on slipping down the lens.  This bulkiness can lead to aesthetic concerns, making patients reluctant to wear them consistently. Even patients wearing aphakic glasses have adaptation issues with the glass at first. 

"We Care, You See” - Vision Concern Clinic

Today we intend to educate people on conditions like aphakia which is often confused with pseudophakia. Watch out for the symptoms and signs in your and your loved one's eyes. 

If you have any prevailing issues in your eyes, book conveniently online or offline appointments with our experienced eye care professionals. You can also directly visit our clinics in Makal Bari, Lazimpat, and Boudha (Tushal). 

FAQs

Is aphakia a childhood cataract?

Aphakia and cataracts are two different cases, not to confuse it with childhood cataracts. When cataracts are surgically removed in infants without IOL then the chances of aphakia are seen. 

Also, children get affected by cataracts due to the abnormal lens development during pregnancy. Similarly, congenital and developmental cataracts are more viable and found in young infants.