Most people with aphakia require some type of vision correction, although people who were extremely near-sighted prior to they ended up being aphakic in some cases need no correction for range or near vision. Find out about this condition and how it affects vision.
Aphakia, or absence of the lens, is an eye disease of congenital or acquired origin, which is accompanied by refractive pathology, decreased visual acuity and inability to accommodation. Congenital aphakia is one of the orphan diseases, and its incidence in the population has not been studied sufficiently. At the same time, the number of postoperative aphakias resulting from cataract extraction increases every year. The risk of developing an acquired form of the disease increases sharply at the age over 40. The number of acquired forms of the disease is predicted to increase in economically wealthy countries. The development of both congenital and acquired forms of the pathology is not affected by race and gender.
So, what is aphakia? The lack of the lens of the eye is referred to as aphakia. The lens is an almost transparent structure that sits behind the iris, which is the colored part of the eye that expands and contracts depending on the amount of light that reaches it.
The lens is biconvex, meaning that it curves external on both sides, and its sole function is to focus light rays onto the retina. People may have a lens surgically got rid of, for example, during cataract surgery.
Really hardly ever a person may be born without one or both lenses, a condition referred to as genetic aphakia. Aphakia can likewise arise from dislocation of one or both lenses as a result of injury. If you have aphakia, your capability to focus suffers and you will have trouble seeing.
Causes of Aphakia
There are three main causes of aphakia:
- Aphakia brought on by a genetic flaw: Congenital aphakia has two types – a primary from that causes severe eye malformations, and a less severe secondary kind. Anomalies in the FOXE3 gene have been recognized in families with aphakia.
- Aphakia after surgery: Aphakia is typically connected with the surgical elimination of a cataract.
- Aphakia after injury: Trauma can cause extrusion of the lens (when the lens is pushed or forced out of location), or dislocation of the lens.
The clinical classification includes two forms of the pathology – congenital aphakia and acquired. Congenital aphakia is an orphan (rare) disease with a poorly studied frequency of occurrence in the population. Acquired aphakia is usually a pathology occurring after surgical intervention, usually after cataract extraction. The risk of acquired aphakia increases dramatically in people after the age of 40. And in economically developed countries, this form of pathology is already predicted to increase. The occurrence of aphakia (congenital or acquired) has nothing to do with gender or race.
Specialists divide congenital aphakia into two varieties: primary, resulting from aplasia (absence) of the crystalline lens, and secondary, resulting from its resorption (resorption) in utero. According to the localization of the anomaly, the absence of the lens is unilateral (monocular) and bilateral (binocular).
The main reason for congenital aphakia is a disorder of the lens formation at the embryonic stage of development. For example, in aplasia of the crystalline lens, the crystalline vesicle does not separate from the outer ectoderm. Normally, PAX6 and BMP4 genes are responsible for this process. According to the degree of reduction in their expression, at certain stages of embryonic development, anterior lenticones, anterior capsular cataracts or Peters anomalies, which are combined with the absence of the lens, may occur. There is experimental evidence that the primary form of congenital aphakia may also be due to the delayed development of the structures of the eye at the stage of cornea-crustal contact.
The secondary form of the disease occurs in idiopathic spontaneous lens absorption. According to one hypothesis, it develops through a spontaneous mutation due to a disorder of the basal membrane structure that forms the lens capsule during embryogenesis.
The main cause of acquired aphakia is surgery, in particular cataract extraction, as well as dislocation and subluxation of the lens. In addition, the pathology may be caused by a penetrating wound or contusion of the eye.
Symptoms of aphakia
One of the typical signs of aphakia is iris trembling or iridodonesis, which can be detected by eye movement. Examination reveals a decrease in visual acuity and loss of accommodation ability. Unilateral form of aphakia is considered especially unfavorable in prognosis, because the pathology is complicated by aniseykonia (condition in which pupils of the healthy and affected eyes differ in size). Abnormality induced by an organic pathology manifests as different size of the images on the retina of one and the other eye causing sharp impairment of binocular vision.
Congenital aphakia is characterized by progressive visual impairment and relative stability of other clinical symptoms. Lack of timely treatment may lead the patient to blindness.
Postoperative aphakia differs in the stages of the underlying disease, which caused the surgery to remove the lens. In case of traumatic aphakia, the clinical picture is characterized by a progressive increase in the symptomatology. One of the early manifestations is a severe pain syndrome accompanied by the increase of local edema and gradual decrease of visual acuity.
Asthenopic complaints of patients with aphakia include: blurred vision, double vision, inability to fixate. Sometimes aphakia is accompanied by nonspecific manifestations. These may include headaches, high irritability, and general weakness.
Congenital aphakia, as well as removal of the lens at an early age can be complicated by microphthalmia. When the crystalline lens capsule is completely absent, only the borderline membrane limits the vitreous body, which provokes the development of vitreous hernia. If the borderline membrane ruptures, the contents of the vitreous body fills the front chamber of the eye. The use of contact correction in aphakia can provoke corneal scarring and keratitis.
People with aphakia have malfunctioning vision and suffer from hypermetropia, or long sightedness.
While the term long sightedness may appear like it indicates the ability to see cross countries, it does not. A person with “high” long sightedness – that is, somebody who is very long spotted – has a prescription or visual acuity of +4.00 or more and is likely to need glasses for both range and near vision.
Aphakia also causes loss of accommodation, suggesting that the eye can not preserve its focus on a things as that object moves better or further away.
Other vision modifications you may discover include erythropsia, where objects appear reddish, and cyanopsia, in which everything appears to have a blue tint. Either of these symptoms can take place after cataract surgery and are temporary.
The colors become magnified because the missing out on lens lets in a lot more sunshine, and the blue and red rays that were when taken in by the lens now reach the retina.
How Is Aphakia Diagnosed?
Your eye doctor can determine whether you have actually aphakia by analyzing you and taking a look at your medical history. There may be additional need to suspect aphakia if you have previously had cataract surgery.
There are several signs that can indicate a missing lens:
- A scar in the limbal ring (the black ring around the iris); this might appear in an individual who has actually gone through surgery
- Iridodonesis – the iris wiggles because it does not have the assistance of the lens
- The finding of a small hypermetropic fundus (the fundus is the interior surface of the eye, opposite the lens, and hypermetropic means that the eyeball is too short, so light doesn’t focus clearly on the retina, however rather behind it).
An eye evaluation is carried out to identify your visual acuity/prescription (distance, near vision, refraction). If you struggle with aphakia, this will validate the lack of the lens. The cornea, iris, anterior chamber, and fundus will be analyzed and your eye pressure will be evaluated.
In addition to a general eye examination, the diagnosis of aphakia requires a number of special eye examinations: eye biomicroscopy, visometry, gonioscopy, refractometry, ophthalmoscopy, and ultrasound.
Visometry is indicated for all patients, it reveals the degree of visual acuity deterioration, which is necessary before eye correction. Gonioscopy reveals the increase in the depth of the anterior chamber of the eye. Ophthalmoscopy allows to detect associated pathologies and choose the further treatment tactics. In addition to scarring of the retina and chorioidea, aphakia is often accompanied by chorioretinal dystrophy of the central retinal region, chorioretinal foci on the retinal periphery, and partial atrophy of the optic nerve.
In case of unilateral aphakia, refractometry technique allows to detect a decrease of refraction of 9.0-12.0D in the eye without the crystalline lens. In children after removal of congenital cataract, hyperopia occurs, averaging 10.0 to 13.0 D. In congenital aphakia, the occurrence of microphthalmos also contributes to farsightedness.
It is not possible to visualize the optical section of the lens by biomicroscopy. It is not often possible to detect only the remnants of the capsule. There is no reflection from the anterior and posterior surfaces of the lens in the Purkinje-Sanson figure test.
How Is Aphakia Treated?
Aphakia can be remedied with glasses, contacts, or surgery. Aphakic glasses can just be used if the condition impacts both eyes, and there are numerous disadvantages for those who use them, most notably a greater than normal zoom, a considerable decrease in visual field, and the cosmetically undesirable appearance of the thick lenses, which magnify the eyes.
There are two methods of correcting the problem – surgical and conservative (with glasses or contact correction). Glasses are prescribed in the bilateral form of the pathology. Two pairs may be needed. They will be equipped with very strong optical power, and the glasses themselves will be convex. Aphakia is often accompanied by astigmatism. Then a cylindrical component is added when selecting spectacle lenses. The glasses will be massive and uncomfortable. An alternative to glasses is contact optics. Lenses are convenient for unilateral and bilateral types.
Surgery is accompanied by the introduction of an artificial lens – an intraocular lens (IOL) – into the eye. This lens is fabricated according to the corresponding visual organ values, which are calculated on the computer.
It is important to start timely treatment of the pathological condition of the missing lens. If the disease is neglected, the person may lose his vision completely and irrevocably, and he will be given a disability. To avoid aphakia, it is necessary to take care of vision, avoid eye trauma and be systematically examined by an ophthalmologist.
Treatment of infants with aphakia might involve using specialized contact lenses. These contacts lenses are safe for the baby to sleep in and they can be used for a longer period than conventional contact lenses.
In addition to using contact lenses, infants with aphakia may need eye drops or an eye spot – or both – to encourage making use of the eye with aphakia. Treatment for aphakia in children and babies is crucial; if the condition goes without treatment it can result in amblyopia.
Inning accordance with the American Association for Pediatric Ophthalmology and Strabismus, both surgical and optical treatment must be supplied urgently for youth cataracts. After the cataracts are gotten rid of, the parents need to pick the type of optical correction that will be used.
The choices consist of aphakic (high power) contact lenses with bifocal glasses; aphakic (high power) glasses; and intraocular lenses with bifocal glasses. Aphakic contact lenses offer optimal optical correction.
Adults with cataracts go through cataract surgery with intraocular lens implantation. An artificial, synthetic lens is put inside the eye to changes the focusing power of a natural lens that is surgically gotten rid of.
This routine procedure results in couple of complications. Results of cataract surgery are normally great. The majority of have substantial enhancement in vision.
While implantation of an intraocular lens is routine in adults, it can cause substantial vision problems, such as myopia, in children. When to implant intraocular lenses in a child is questionable, and the procedure brings risks of complications at any age.
Children who go through intraocular lens implantation, in addition to those with high-power contact lenses, will also require bifocal glasses to fine-tune the refraction and allow vision at range and near.
Correction of aphakia
The refraction of the eye is drastically removed after removal of the lens. This leads to a high degree of hyperopia. Optical aids can compensate for the refractive power of the removed crystalline lens. In addition to optical aids, it can be compensated with an artificial lens.
This is corrected by contact or spectacle correction in rare cases. An emmetropic eye requires a spectacle dispenser with a power of +10.0 Dpc when correcting aphakia. The refractive power of the removed lens is much higher at 19 diopters. The spectacle lens has a different place in the optical system of the eye, which explains the significant difference. The glass lens is surrounded by air, while the crystalline lens is filled with fluid, which has almost the same index of light refraction.
With hyperopia the power of the glass is increased by a given power of dioptres, with myopia the glass must be of a lower optical power. With myopia of 19 diopters before surgery, the strong optic power after surgery can be neutralized by removing the lens, allowing you to do without glasses.
Accomodation is impossible for the aphakic eye. This necessitates the use of spectacles three diopters stronger for near vision than for far vision. Monocular aphakia does not allow for spectacle correction. This eye condition requires intraocular or contact correction.
Intraocular aphakia correction is nothing more than surgery. The lens that has become cloudy and dislocated is replaced with a lens with the appropriate optical power. The dioptric power is determined by the surgeon. He uses monograms, special charts and computer programs for this purpose.
Such parameters as refractive power, crystalline lens thickness, anterior chamber depth, and eyeball length are necessary for the calculation. General refraction is allowed with the patient’s own wish.
Emmetropia is recommended for those who drive a car, play sports, or simply prefer outdoor activities to passive ones. When the second eye is nearsighted, planning for low myopic refraction is allowed. Patients who are confronted with precise work and their workplace is a desk are also recommended for low grades of myopic refraction.
What Is the Prognosis for Aphakia?
The diagnosis for patients with aphakia is normally good unless there are complications. During youth, the size of the eye and the refractive error modification quickly. Optical correction in children needs frequent modifications to guarantee that ideal vision is kept. Failure to make these changes in a timely manner may result in permanent visual loss.
Concerns to Ask Your Doctor
- What treatment choice would be best for my aphakia?
- Do certain symptoms portend a worse diagnosis?
- What are the possibilities my other children will develop this condition?
- After surgery, will I still require optical correction with glasses or contacts?
- Which kinds of tests can we expect during the diagnosis?
- Will I continue to have vision issues even with correction?
Q&A
What do aphakic people see?
Even with the lens removed (a condition known as aphakia) the patient can still see, as the lens is only responsible for about 30% of the eyes’ focusing power. However, aphakic patients report that the procedure has an uncommon side effect: they can see ultraviolet light.
How can you tell the difference between aphakia and Pseudophakia?
is that aphakia is the absence of the lens of the eye while pseudophakia is the alternative of the natural crystalline lens of the eye with a synthetic lens.
Why is aphakia student black?
The student appears jet black in the lack of lens.
How does Aphakia cause glaucoma?
Ghost cells are released as a result of the chronic vitreous hemorrhage in the patients with aphakic eyes. The ghost cells are present in the anterior chamber and the vitreous humor and might settle and block the outflow through the trabecular meshwork. The obstruction then leads to the boost in IOP.
What is pseudo Aphakia?
A genetic condition in which the crystalline lens has deteriorated and been changed by mesodermal tissue.
What is aphakic eye?
Aphakia is a condition in which you’re missing out on the lens of one or both of your eyes. You can be born that way or lose the lens due to an injury. Or your doctor may remove it during an operation for cataracts. When you have aphakia, it’s tough to see things clearly with the impacted eye.
What is aphakic refraction?
Abstract. The refraction of aphakia depends mainly on the refraction prior to elimination of the lens; and also on the modifications of shape of the cornea after operation. The refraction and vision in the other eye influence what it is practical to do with fixing lenses.
