Cataract basics - Symptoms , Diagnosis , Treatment , Risks

What is a cataract?

A cataract is clouding of the natural lens in the eye. The normal lens is clear and helps focus light on the retina at the back of the eye. As the cataract develops , it blocks and scatters the light and can cause night vision loss.

 

Courtesy - Columbia Asia Hospitals

 

Symptoms

Cataract causes blurring of vision. This may be present in dim light conditions or in bright light depending upon the type of cataract. It may also lead to frequent changes in the glasses prescription.

Diagnosis

A Comprehensive eye exam is done to:

• Check how well you see things up close and far away
• Measure the pressure inside your eye (intra ocular pressure) using a special device
• Look into the back of your eyes using an ophthalmoscope to check the retina and signs of nerve damage

Treatment

The main treatment for cataract involves surgery to remove the cloudy lens and replace it with a clear artificial lens. This is called an intraocular lens implant, which is placed permanently in the eye. The lens is available in different sizes, power, material & design and the surgeon will suggest the one most suitable for you.

Type of intra ocular lenses available:

• Monofocal lenses: with a fixed focus for near, mid distance or distant focus. Usually needs mild correction of the residual visual deficiency with glasses.
• Multifocal lenses: to correct both the near and distant vision such that dependency on glasses is minimal
• Toric lenses: different from normal lenses in design and used in those with cataract and astigmatism. The patients will have a minimal power for distance and will need reading glasses
• Toric multifocal lenses: used in patients with cataract and astigmatism to correct both near and distant vision

Risks and complications

• Complete or partial loss of vision, which may be due to infection , scarring, hemorrhage and inflammation
• Occasional enlargement of the incision, requiring suturing
• Posterior capsular dehiscence. The posterior capsule  provides support to the intra ocular lens and is occasionally ruptured during surgery and requires a modified approach. In such cases the lens may or may not be implanted in the same sitting 
• The lens may drop into the surrounding cavity due to weak posterior capsule during surgery and in which case the surgery will be deferred
• Damage to the corneal endothelium beyond acceptable limits. In patients with a weak cornea this may necessitate another surgery
• Rarely intra-ocular bleed
• Post operative infection
• Retinal complications such as cystoid macular edema, retinal detachment causing decreased vision or total loss of vision
• Delayed post operative complications such as corneal clouding, posterior capsular opacification (which may need a laser) and glaucoma (increased intra-ocular pressure)
• Very rarely severe infection which may require removal of the eyeball to prevent systemic spread

During administration of local anesthetic rarely there may be an ocular perforation, optic nerve injury or hemorrhage, which may result in reduced or total loss of vision. Hemorrhage may require postponement of surgery by six weeks.

 

Courtesy -  An informative series issued in public interest by Columbia Asia Hospitals, Bangalore - is meant for informational purpose only , it is not a substitute for a valid opinion from a medical professional. For expert advise , consult medical profession by taking an appointment