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

SPECTACLES

The lenses fitted in a frame constitute the spectacles. It is a common, cheap and easy method of prescribing corrective lenses in patients with refractive errors and presbyopia. Some important aspects of the spectacles
are as follows:

Lens materials
1. Crown glass of refractive index 1.5223 is very commonly used for spectacles. It is ground to the appropriate curvature and then polished to await the final cutting that will enable it to

SPASM OF ACCOMMODATION

(continue  ACCOMMODATION ANOMALIES)

Spasm of accommodation refers to exertion of abnormally excessive accommodation.

Causes
1. Drug induced spasm of accommodation is known to occur after use of strong miotics such as echothiophate and DFP.

2. Spontaneous spasm of accommodation is occasionally found in

INSUFFICIENCY OF ACCOMMODATION

(continue  ACCOMMODATION ANOMALIES) Insufficiency of accommodation

The term insufficiency of accommodation is used when the accommodative power is significantly less than the normal physiological limits for the patient's
age. Therefore, it should not be confused with presbyopia in which the physiological insufficiency of accommodation is normal for the patient's age.

Causes
1. Premature sclerosis of lens.
2. Weakness of ciliary muscle due to

ANOMALIES OF ACCOMMODATION

Anomalies of accommodation are not uncommon.
These include: (1) Presbyopia, (2) Insufficiency of accommodation, (3) Paralysis of accommodation, and (4) Spasm of accommodation.(last three anomalies discussed in other posts)

PRESBYOPIA
Pathophysiology and causes:

Presbyopia (eye sight of old age) is not an error of refraction but a condition of physiological
insufficiency of accommodation leading to a progressive fall in near vision.

Pathophysiology. To understand the pathophysiology of presbyopia a working knowledge about
accommodation (as described in this post) is mandatory. As we know, in an emmetropic eye far point is infinity and near point varies with