PSEUDOPHAKIA

S.ARYA DAS1st YR 2nd SEM

BACHELOR OF OPTOMETRYBHARTIMAIYA COLLEGE OF OPTOMETRY

INTRODUCTION

PHAKIA

APHAKIAPSEUDOPHAKIA

INTRODUCTION

PHAKIA :- The condition of the presence of natural lens .

APHAKIA :- The condition of absence of crystalline lens from the eye.

PSEUDOPHAKIA :- The word “pseudo” means false . Hence the condition of the presence of

a false or artificial lens is known as “pseudophakia”.

PSEUDOPHAKIA

The condition of aphakia when corrected with implantation of an

IOL is referred to as pseudophakia.

It is also known as artiphakia (as an artificial lens is

implanted).

INTRAOCULAR LENS

An intra ocular lens is a lens implanted in the eye used to treat cataract or aphakic eye. The most common IOL for cataract is known as pseudophakic IOLs which works by replacing the crystalline lens which have been clouded over by cataract.

CALCULATION OF IOL POWER

The power of an IOL to be implanted is calculated by taking in consideration the keratometric reading and axial length of the eye ball.

The most commonly used formula for the implantation of IOLS is based on the “SRK” (Sanders Retzlaff and Kraff).

SRK

The SRK formula is gives as:-

P = A-2.5L – 0.9K.

P = dioptric power of the implanted IOL,

A = constant specific for each lens,

L = axial length in mm

K = average keratometry in dioptres.

REFRACTIVE STATUS OF PSEUDOPHAKIC EYE

EMMETROPIA

CONSECUTIVE MYOPIA

CONSECUTIVE HYPERMETROPIA

ASTIGMATISM

EMMETROPIA

It is produced when the power of the IOL implanted is exact. It is the most ideal situation. Such patients require plus glasses for near vision.

CONSECUTIVE MYOPIA

Consecutive myopia occurs when the IOL implanted

overcorrects the refraction of eye. Such patients

require glasses to correct the myopia for distance

vision and may on may not need glasses for distance

vision and additional +2 to +3D for near vision.

CONSECUTIVE HYPERMETROPIA

Consecutive hypermetropiadevelops when the under power IOL is implanted.

Such patients requires plus glasses for distance vision

and additional +2 to +3D for near vision.

ASTIGMATISM

Varying degree of surgery induced astigmatism is also present in pseudophakia

SIGNS OF PSEUDOPHAKIA

Continue...........(for practical knowledge)

REFERENCE

Optics & refraction

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