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Aphakia

Copy of Power Point presentation of

Undergraduate (MBBS-prefinal year) lecture

taken by

Dr Sanjay Shrivastava

Professor of Ophthalmology

Gandhi Medical College

Bhopal (M.P.)

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18 June 2014 Prof Sanjay Shrivastava 2

Aphakia

When the crystalline lens has been removed

condition is called aphakia. In this condition

the crystalline lens is absent from its normal

position.

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Causes of Aphakia

1. Congenital:

a. True absence of lens, is a rare congenitalcondition,

b. Posterior dislocation of lens (lens iscompletely out of pupillary area, in posterior

segment).

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Causes of Aphakia

2. Acquired:

a. Surgical removal of lens

b. Complete absorption of lens in children

following trauma (act like surgical

procedure, needling)

c. Posterior dislocation of lens (usually

traumatic)

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Symptoms of Aphakia

Marked diminution of vision (in previously

emmetropic individuals)

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Signs of Aphakia

1. Markedly reduced visual acuity

2. Conjunctival scar may or may not be

there

3. Corneo-scleral / corneal scar

4. Deep anterior chamber

5. Tremulousness of iris

6. Jet black pupil

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Signs of Aphakia

7. Absence of lens

8. High hypermetropic fundus

9. High hypermetropic refraction

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Optics in Aphakia

Eye becomes high hypermetropic due to

removal of lens. There is only one

converging structure i.e. Cornea, whichseparates two media of different refractive

indices, air and aqueous plus vitreous.

Anterior focal distance becomes 23 mm(from 15 mm) and posterior 31 mm (from

24 mm)

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Optics in Aphakia

If the aphakic eye is 31 mm long

(equivalent to -21 D axial myopia) the

parallel light rays falling on cornea willfocus on retina.

There is total loss of accommodation inaphakic eye.

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Optics in Aphakia

Astigmatism, against the rule in phaco

incision in upper sector , which is

minimum. With the rule astigmatism inconventional ECCE with sutures in place in

upper part and this astigmatism decreases

after removal of sutures.

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Treatment

Spectacle

Contact Lens

Intra-ocular lens implantation

a. Posterior Chamber IOL

b. Iris claw IO lensc. Anterior Chamber IOL

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Treatment

Spectacle :

Indications: Bilateral Aphakia, High myopic

patients (calculated IOL power less than 8

D) under going cataract surgery, and when

patient refuses IOL implantation surgery.

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Treatment

Spectacle: Patient who was emmetropic prior to

lens removal operation usually requires

For Distance: +10 D Sph and Astigmaticcorrection (usually +1 to +2 D Cyl at 180 deg in

case of against the rule astigmatism, wherein

vertical curvature of cornea is flatter than

horizontal, and at 90 deg in case of with the ruleastigmatism)

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Treatment

Spectacle Correction:

For Near: Addition of +3 D Sph to distancespherical correction.

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Disadvantages of Aphakic

SpectacleDisadvantages of aphakic spectacle:

1. Magnification of image (seen by patient) by

30%2. Lack of eye-hand coordination

3. Reduced visual field and poor peripheral /

eccentric acuity

4. Ring scotoma from prismatic effect of the edge

of the convex lens. Jack in the box phenomenon

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Disadvantages of Aphakic

Spectacle5. Physical discomfort of wearing heavy

spectacle and cosmetically intolerable thick

spectacle6. Wearing different optical correction for

different distances

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Contact Lens correction

Indications for use of Contact lens in aphakicpatients:

Young children, where IOL implantation is not

considered safe (usually below the age of 2 years)Other aphakic patients where IOL has not beenimplanted, and cornea is suitable for contact lensfitting.

With contact lens magnification is around 8% whichis tolerable, without causing binocular diplopiaeven in uniocular aphakics.

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Disadvantages of Contact

Lens1. Fitting and removal of contact lens is

cumbersome procedure for most of our patients

2. Contact lens requires proper hygiene andcleaning of contact lenses

3. It may be difficult for elderly patients with

tremors to manipulate contact lenses

4. Additional near (and sometimes intermediate

distance) correction is required

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Intra-ocular lens (IOL)

implantationBest tolerated, there are no optical aberrations,

magnification is negligible (usually 1-2%),

IOL can be implanted in almost all casesundergoing cataract surgery

Additional near (and sometimes intermediate

distance) correction is required (except inthose patients where multi-focal IOL is

implanted)

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Intra Ocular Lens Implantation

1. Done at the time of Cataract Surgery OR

2. Secondary IOL (IOL implantation done in an

aphakic eye). This may be posterior chamberIOL implantation, in case where posterior

capsule is intact/present. Iris claw or anterior

chamber IOL. Posterior chamber IOL

implantation is preferred over other two types asthere is minimum risk of complications.

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Posterior Chamber IOL

Implantation In the bag posterior chamber IOL

or

Sulcus fixated posterior chamber IOL

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Posterior Chamber IOL In the bag

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Posterior Chamber IOL Sulcus Fixated

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Anterior Chamber IOL

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Anterior chamber IOL

Complications:

There is higher risk of corneal endothelial

decompensation leading to corneal edema.

Uveitis, Haemorrhage and Glaucoma

(UGH) syndrome.

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