What is a Cataract?

Cataract is clouding of the lens inside the eye which leads to a decrease in vision. It is the most common cause of blindness and is conventionally treated with surgery. Sight loss occurs because opacification of the lens obstructs light from passing and being focused on the retina at the back of the eye. Those with cataracts often experience difficulty in appreciating colours and changes in contrast, driving, reading, recognizing faces and coping with glare from bright lights. The causes are aging, trauma, ultraviolet-B rays, genetic abnormalities, skin diseases, smoking, metabolic diseases and medications.

Cataract and Refractive Lens Surgery

Special Types of Cataract:

Traumatic: Cataract may occur following injury to the eye, during an accident or the use of blunt force or while playing a sport like tennis or badminton. This kind of cataract may vary from minor type of opacification of the natural lens to a profound damage to the natural lens along with injury to outer layers of eye and the posterior part of the eye as well.

Posterior Polar Cataract: A posterior polar cataract is a round, discoid, opaque mass that is composed of malformed and distorted lens fibres located in the central posterior part of the lens and is often difficult to remove and may need a change in technique. Intraocular lenses of specific designs are needed in these cataracts.

Subluxated Cataract: This is a cataract where the lens has partial displacement from its natural position due to loss of support of the natural lens. Patient may complain of diminution of vision and/or doubling of images in one eye. This condition may be present since childhood due to a metabolic disease or may occur due to injury.

Post LASIK / Post RK Cataract surgery

For patients who have developed cataract but have earlier undergone surgeries like LASIK/RK to get rid of their glasses, we offer customized solutions for cataract surgery by performing calculations on “state of the art” systems and then offer the “Best Fit” intraocular lenses for their eyes. This involves analysis on highly specialized equipment like the Pentacam, iTrace, OPD-III and online calculation tools.

Cataract and Refractive Lens Surgery

Treatment for cataract:

Treatment of Cataract is done by doing eye surgery where the natural cataractous (opaque) lens is removed and replaced with a clear artificial intraocular lens (IOL). This procedure is done with the help of various instruments by the operating cataract surgeon. There are different techniques of doing this surgery.

Steps of Cataract Surgery

Anaesthetic drops– or jelly is applied over the eye /an anaesthetic injection is given around the eye to make it numb

Corneal incision– Two to three cuts are made through the clear cornea to allow insertion of instruments into the eye.

Capsulorhexis– A needle or small pair of forceps are used to create a circular opening in the capsule (cover) of the lens.

Lens removal- The lens consists of a hard part, the nucleus and a soft part, the cortex. The nucleus is removed by various means, either as a whole or after being cut into small bits.

Irrigation and aspiration– The cortex, which is the soft outer layer of the cataract, is aspirated or sucked away. The fluid removed is continually replaced with a special solution to prevent collapse of the eye.

Lens insertion– A plastic, foldable lens is inserted into the capsular bag that formerly contained the natural lens. The final step is to bring the eye to its normal pressure and seal the wounds that have been created. Stitches are usually not required, but may be needed in certain situations.

Types of Cataract Surgery

SICS-Small Incision cataract surgery

This is a cataract surgery wherein a 6-7 mm cut is made by the surgeon and the cataract is removed as a whole preserving the capsule of the lens. Then the new artificial intraocular lens is inserted into the lens capsule through the same wound to replace the old lens. Then the wound is sealed and usually stitches are not required.

Phaco/Phacoemulsification

Phacoemulsification refers to modern cataract surgery via a small 2-3 mm cut, in which a handheld probe is used to break up and emulsify the lens into liquid using ultrasound energy. The resulting’emulsion’ is sucked out. After these steps, the artificial intraocular lens is inserted inside the eye.

Femtosecond Laser Assisted Cataract Surgery Using TM LenSx , alcon platform and Catalys, AMO platform

The role of femtosecond laser in cataract surgery is to assist, replace and automate several aspects of cataract surgery. These include the creation of the initial surgical incisions in the cornea, the capsulotomy, and the fragmenting (breaking up) of the lens. The femtosecond laser may also produce incisions within the peripheral cornea to aid the correction of pre-existing astigmatism. The lens which has already been broken up into small bits is then removed by the surgeon and the intraocular lens is implanted. This kind of surgery is known to have lesser complications because of improved precision and repeatability of surgical steps and this could enhance the results and also is a safer option for complex cataracts.

Types of Intraocular Lenses

Monofocal IOLs are implantable lenses made of acrylic or silicone materials and placed permanently in the eye after removal of the eye’s natural lens. Monofocal lenses have a single zone of clear focus, usually set for excellent distance vision, but require the use of reading glasses for near tasks, like reading

Toric IOLs are intraocular lenses that reduce the effect of pre-existing corneal astigmatism by reducing the residual refractive cylinder and improve the quality of uncorrected distance vision.

Multifocal IOLs incorporate both distance and near powered segments in one lens. The base power bends light coming from distant objects to a single focal point on the retina. The higher power segments bend light from near objects to the same focal point on the retina. Multifocal IOLs greatly reduce the likelihood of wearing glasses or contact lenses after surgery.

Scleral Fixated IOLs (SFIOL) – Ideally, the lens is placed in the capsular cover (bag) of the lens using the support structure of the natural lens. However, there will always be instances where “in the bag” implantation isn’t possible, requiring that the IOL be sutured to the sclera with special permanent sutures. Trans-scleral suturing of Posterior Chamber IOL or Scleral Fixated Intraocular lens (SFIOL) is wellestablished and is a good option in patients with insufficient capsular support or zonular support, either as a primary or secondary implantation. The other options in these cases are Anterior Chamber IOLs and Iris Fixated IOLs. Each has its merits and demerits.

Cataract and Refractive Lens Surgery

General pre-operative Instructions

  1. You will be informed about your pre-operative laboratory examinations and cardiopulmonary clearance schedule. The pre-operative investigation includes some blood tests and examination by the physician to determine your fitness for surgery. It also includes specialized eye tests to find out the IOL which is most suitable for your eye. It takes between 1-2 hours for the entire testing.
  2. If you wish to have the examination performed elsewhere, kindly bring all the results with you on the day of your cardiopulmonary clearance with the physician.
  3. If you are diabetic, please discuss with the physician about the medication you should take before surgery.
  4. Please make arrangements for a responsible adult to be with you in the hospital on the day of the surgery.

Cataract and Refractive Lens Surgery

Potential complications with cataract surgery

  • Though cataract surgery is one of the most successful procedures in all of medicine, complications may still occur.
  • Over 98% of cataract surgeries are successfully completed without surgical complications, and more than 95% of patients have improved vision.
  • Most complications are minor, such as swelling of the cornea or retina, increased pressure in the eye, and droopy eyelid.
  • In general, the risk of severe visual loss is very rare, but may occur as a result of infection or bleeding inside the eye, or even retinal detachment, which may occur months or years after a perfectly successful cataract surgery.
  • Sometimes the vision after cataract surgery does not improve to the full extent due to other diseases that are present like age related macular degeneration (ARMD), diabetic retinopathy, glaucoma and other conditions.
    Your doctor would have checked for these conditions and if detected the surgery would have been performed under guarded visual prognosis ( GVP)