Refractive surgery for presbyopia

Refractive surgery for presbyopia, still under trial,
includes :

• Monovision LASIK, i.e., one eye is corrected for distance and other is made slightly near sighted.
• Monovision conductive keratoplasty (CK) is being considered increasingly to correct presbyopia in one eye. Principle is same as for correction of hypermetropia.
• Scleral expansion procedures are being tried, but results are controversial.
• LASIK-PARM i.e., LASIK by Presbyopia Avalos Rozakis Method is a technique undertrial in which the shape of the

Refractive surgery for hyperopia

In general, refractive surgery for hyperopia is not as
effective or reliable as for myopia. However, following
procedures are used:

1. Holmium laser thermoplasty has been used for
low degree of hyperopia. In this technique, laser spots
are applied in a ring at the periphery to produce central
steepening. Regression effect and induced
astigmatism are the main problems.

2. Hyperopic PRK using excimer laser has also been
tried. Regression effect and prolonged epithelial
healing are the  

Complications & Treatment of myopia

Complications
(i) Retinal detachment; (ii) complicated cataract; (iii) vitreous haemorrhage; (iv) choroidal haemorrhage (v) Strabismus fixus convergence.


Treatment of myopiageneral measures of treatment of myopia
1. Optical treatment of myopia constitutes
prescription of appropriate concave lenses, so
that clear image is formed on the retina (Fig. 1).

Refraction in a myopic eye
corrected with concave lens.

The basic rule of correcting myopia is converse of that in 

Treatment of hypermetropia

Treatment
A. Optical treatment. Basic principle of treatment is to prescribe convex (plus) lenses, so that the light rays are brought to focus on the retina (Fig. 1). Fundamental rules for prescribing glasses in hypermetropia include:
 
1. Total amount of hypermetropia should always be discovered by performing refraction under
complete cycloplegia.

2. The spherical correction given should be comfortably acceptable to the

Complications of HYPERMETROPIA

If hypermetropia is not corrected for a long time the following complications may occur:
1. Recurrent styes, blepharitis or chalazia may occur, probably due to infection introduced by repeated rubbing of the eyes, which is often done to get relief from

HYPERMETROPIA

Hypermetropia (hyperopia) or long-sightedness is the refractive state of the eye wherein parallel rays of light coming from infinity are focused behind the retina with accommodation being at rest (Fig. 1). Thus, the posterior focal point is behind the retina, which therefore receives a blurred image.

Fig. 1. Refraction in a hypermetropic eye.

Etiology
Hypermetropia may be axial, curvatural, index, positional and due to absence of lens.
1. Axial hypermetropia is by far the commonest form. In this condition the total refractive power of eye is normal but there is an axial shortening of eyeball. About 1–mm shortening of the anteroposterior diameter of the eye results in 3 dioptres of hypermetropia.

2. Curvatural hypermetropia is the condition in which the curvature of cornea, lens or both is
flatter than the normal resulting in a decrease in the refractive power of eye. About 1 mm increase in radius of curvature results in 6 dioptres of hypermetropia.

3. Index hypermetropia occurs due to