Treatment
Optical principle is to correct the error by convex lenses of appropriate power so that the image is formed on the retina (Fig. 1).
Modalities for correcting aphakia include:
(1) spectacles, (2) contact lens, (3) intraocular lens, and (4) refractive corneal surgery.
1. Spectacles prescription has been the most commonly employed method of correcting aphakia, especially in developing countries. Presently, use of aphakic spectacles is decreasing. Roughly, about +10 D with cylindrical lenses for surgically induced astigmatism are required to correct aphakia in previously emmetropic patients. However, exact number of glasses will differ in individual case and should be estimated by refraction. An addition of +3
to +4 D is required for near vision to compensate for loss of accommodation.
Advantages of spectacles. It is
a cheap, easy and safe method of correcting aphakia.
Disadvantages of spectacles. (i) Image is magnified by 30 percent, so not useful in unilateral aphakia (produce diplopia). (ii) Problem of spherical and chromatic aberrations of thick lenses. (iii) Field of vision is limited. (iv) Prismatic effect of thick glasses. (v) 'Roving ring Scotoma' (Jack in the box phenomenon). (vi) Cosmetic blemish especially in young aphakes.
2. Contact lenses. Advantages of contact lenses over spectacles include:
(i) Less magnification of image.
(ii) Elimination of aberrations and prismatic effect of thick glasses. (iii) Wider and better field of vision.
(iv) Cosmetically more acceptable. (v) Better suited for uniocular aphakia.
Disadvantages of contact lenses are:
(i) more cost;
(ii) cumbersome to wear, especially in old age and in childhood; and (iii) corneal complications may be associated.
3. Intraocular lens implantation is the best available method of correcting aphakia. Therefore, it is the commonest modality being employed now a days..
4. Refractive corneal surgery is under trial for correction of aphakia. It includes:
i. Keratophakia. In this procedure a lenticule prepared from the donor cornea is placed between the lamellae of patient's cornea.
ii. Epikeratophakia. In this procedure, the lenticule prepared from the donor cornea is stitched over the surface of cornea after removing the epithelium.
iii. Hyperopic Lasik
Optical principle is to correct the error by convex lenses of appropriate power so that the image is formed on the retina (Fig. 1).
Modalities for correcting aphakia include:
(1) spectacles, (2) contact lens, (3) intraocular lens, and (4) refractive corneal surgery.
1. Spectacles prescription has been the most commonly employed method of correcting aphakia, especially in developing countries. Presently, use of aphakic spectacles is decreasing. Roughly, about +10 D with cylindrical lenses for surgically induced astigmatism are required to correct aphakia in previously emmetropic patients. However, exact number of glasses will differ in individual case and should be estimated by refraction. An addition of +3
to +4 D is required for near vision to compensate for loss of accommodation.
Advantages of spectacles. It is
a cheap, easy and safe method of correcting aphakia.
Disadvantages of spectacles. (i) Image is magnified by 30 percent, so not useful in unilateral aphakia (produce diplopia). (ii) Problem of spherical and chromatic aberrations of thick lenses. (iii) Field of vision is limited. (iv) Prismatic effect of thick glasses. (v) 'Roving ring Scotoma' (Jack in the box phenomenon). (vi) Cosmetic blemish especially in young aphakes.
2. Contact lenses. Advantages of contact lenses over spectacles include:
(i) Less magnification of image.
(ii) Elimination of aberrations and prismatic effect of thick glasses. (iii) Wider and better field of vision.
(iv) Cosmetically more acceptable. (v) Better suited for uniocular aphakia.
Disadvantages of contact lenses are:
(i) more cost;
(ii) cumbersome to wear, especially in old age and in childhood; and (iii) corneal complications may be associated.
3. Intraocular lens implantation is the best available method of correcting aphakia. Therefore, it is the commonest modality being employed now a days..
4. Refractive corneal surgery is under trial for correction of aphakia. It includes:
i. Keratophakia. In this procedure a lenticule prepared from the donor cornea is placed between the lamellae of patient's cornea.
ii. Epikeratophakia. In this procedure, the lenticule prepared from the donor cornea is stitched over the surface of cornea after removing the epithelium.
iii. Hyperopic Lasik
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