http://www.medindia.net 


Presbyopia
 

General Info

The word presbyopia (Prez-bye-OH peeah) is based on a Greek word that means "aging eye". This is a vision condition in which the lens of a persons eye loses its flexibility and makes it difficult for them to focus on nearby objects. In order for us to see images clearly, light rays that allow us to see objects enter the eye, where the lens bends and focuses the rays on the retina. The lens changes shape to accommodate the differences in light coming from objects at different distances.The word presbyopia (Prez-bye-OH peeah) is based on a Greek word that means "aging eye". This is a vision condition in which the lens of a persons eye loses its flexibility and makes it difficult for them to focus on nearby objects. In order for us to see images clearly, light rays that allow us to see objects enter the eye, where the lens bends and focuses the rays on the retina. The lens changes shape to accommodate the differences in light coming from objects at different distances.

 
Causes
 
As we age, body tissues lose their elasticity, likewise the lenses in our eyes
   lose some of their elasticity, the eyes find it difficult to change its focus.
   Presbyopia may seem to occur suddenly, the actual decline takes place over
   the course of many years, it usually becomes noticeable in the early to
   mid-forties.
Presbyopia is a natural aging process of the eye. The lens becomes less
   flexible, more thickened and accommodation is gradually lost. Presbyopia can
   also be combined with short sight, long sight or astigmatism.
 
Symptoms
 

Some signs of presbyopia include the tendency to hold reading materials at
   arm's length, as the vision gets blurred. This is also known as the “short arm
   syndrome”. Most people first notice difficulty reading very fine print like the
   newspaper, prescription on medicine bottles etc., Their eyes become easily
   fatigued when reading a book or computer screen. Some people complain of
   headaches when doing close work and need brighter light to see clearly.

Presbyopia is sometimes confused with long-sightedness, (occurs when the
   cornea is too flat or eyeball too short than the normal eye), whereas
   presbyopia is due to loss of flexibility of the eye.

 
Diagnosis
 

Many people over age 40 self-diagnose presbyopia based on their inability to read clearly at a distance that used to be natural and comfortable. Presbyopia is diagnosed with a routine eye examination. A visual acuity test is performed to determine the focusing power of the eye at different distances. A process called refraction is used to measure the refractive error of the eye.
 
The effects of presbyopia constantly change the ability of the lens to focus properly. As a result, periodic changes in the eyewear are necessary to maintain correct vision. These changes will slow as a person grows older and will probably stop when he reaches his sixties.

 
Treatment
 
The treatment for presbyopia is entirely dependent on the individual’s age, health and interests. The treatment for presbyopia includes reading glasses, bifocals, trifocals, variable focus glasses, contact lenses and surgery.

Lenses: Bifocal contact lenses are designed to give good vision to people with presbyopia. They have two powers on one lens, one to correct distance vision, if that’s needed, and the other to correct near vision.
 
There are contact lenses for presbypopes, called multifocal lenses. It can be obtained in gas permeable or soft lens materials.

Surgical Operations: A special technic Monovision is also available. MonoVision is a painless, non-surgical technique using contact lenses that can help you to see distance and read up-close simultaneously. Contact lenses in which one contact lens has a power to correct distance vision and the other contact lens with a different power to correct near vision are given.

Refractive surgical operations to treat this condition are:

Radial Keratotomy (RK) a procedure which reduces the central corneal curvature sufficiently so as to move the cornea's focus back onto the retina and provide clear vision.
Automated Lamellar Keratoplasty (ALK) in which a thin layer of tissue is removed from the front surface of the corneato reshape it.
Other investigational procedures are Surgical Reverse Presbyopia (SRP) and Anterior Ciliary Sclerotomy (ACS).
At the present doctors recommend Surgical Reverse Presbyopia to healthy individuals between the ages of 40 and 65. The procedure is totally reversible and its effect could last for 10 years. The procedure could be repeated without apparent side effects. This is not performed in India but is being done in Western countries.
Anteror Ciliary Sclerotomy is a surgical incisional technique similar to Radial Keratotomy, it is used to correct up to +2.00 D of presbyopia. The procedure is based on the use of partial thickness radial incisions in the sclera, these incisions allow the sclera to expand, giving more room for the eye to accommodate to close objects for better vision. At present this technic is currently under study in the Foreign countries.
 
More Info
 
The word presbyopia (Prez-bye-OH peeah) is based on a Greek word that
   means "aging eye".
Presbyopia is a natural aging process of the eye.
The lens of a persons eye loses its flexibility and makes it difficult for them
   to focus on nearby objects.
Some signs of presbyopia include the tendency to hold reading materials at
   arm's length, as the vision gets blurred. This is also known as the “short arm
   syndrome”.
Many people over age 40 self-diagnose presbyopia.
The effects of presbyopia constantly change the ability of the lens to focus
   properly.
The treatment for presbyopia is entirely dependent on the individual’s age,
   health and interests.
Bifocal contact lenses have two powers on one lens, one to correct distance
   vision and one for correction of near vision.
A special technic Monovision which is a painless, non-surgical technique
   using contact lenses are available.
Radial Keratotomy (RK) and Automated Lamellar Keratoplasty (ALK) are some
   of the surgical procedures to treat Presbyopia
 
FAQ's
 
Will everyone get Presbyopia?
Yes, as we grow old the crystalline lens within our eye hardens and loses the elasticity that's required to focus on objects up close. This condition can develop as early as 40 or as late as 50.

Which specialist should I consult if I have Presbyopia?
You have to go to an opthalmologist.
 
Glossary
 
Presbyopia - The normal process of aging causes the lens of the eye to become less flexible and the loss of the ability to focus on near objects.
Contact lenses - Lenses which fit directly on the eyeball under the eyelids.
Cornea - The clear tissue in front of the eye resembling a crystal of a watch.
Diplopia - The seeing of one object as two.
Nystagmus - An involuntary, rhythmical movement of the eyeballs.
Opthalmoscope - Device for viewing the interior of the eye or the retina.
Optic nerve - The nerve which carries visual impulses from the retina to the brain.
Optician - A technician who designs, verifies and dispenses lenses, frames and other fabricated optical devices upon the prescription of an ophthalmologist or an optometrist.
Opthalmologist - A physician who is qualified and especially trained to diagnose and treat all eye and visual system problems, as well as diagnose general diseases of the body.
Photophobia - Abnormal sensitivity to light.
Refractive error - A defect in the eye that prevents light from being brought to a single focus exact on the retina.
Pupil - Apature allowing light to enter into the eye regulated by the iris and ciliary muscles.
Retina - Light sensitive membrane at the back of the eye. Light is focused onto this membrane and the retina then transmits this information to the brain as impulses which the brain interprets as sight.
Sclera - The firm white fibrous membrane that forms the white part of the eye.
Visual Acuity - Clarity of vision, with corrective glasses.
 
HIGHLIGHTS
Presbyopia is based on a Greek word that means "aging eye".
The lens becomes flexible, more thickened and accommodation is gradually lost. It is a natural aging process of the eye.
 

Back