Eye Disease - CATARACT

Cataract surgery is one of the safest, most effective types of surgery. It's also one of the most successful.

INTRODUCTION: The opacification of the normal transparent lens is called cataract. The latin word "cataracta" means waterfall imagine trying to peer through a sheet of falling water or through a frosted or fogged up window.

HISTORY: The earliest surgery treatment began in India known as couching. The sclera is incised & then the lens is dislocated backward into vitreous & out of optical axis. This procedure was performed for more than 2000 years until mid-eighteenth century. Great progress in cataract surgery has been made in recent years with the introduction of microsurgical instruments, microscope & modern surgical techniques like phacoemulsification.

In the early stages of cataract development all that is needed correct your vision with glasses is a change inprescription. As the cataract develops and begins to affect your lifestyle, the removal may be required. Cataract surgery the most commonly performed operation is safe and effective in 95% patients with enhancement in vision. During this procedure, the surgeon will first create a small incision with an advanced diamond cutting tool. The surgeon will then peel off the front layer of your lens capsule. Using ultrasound from small sophisticated instruments, the surgeon will break up your cataract into minute fragments. These fragments are then gently suctioned out of the eye through the instrument tool. An intra ocular lens is then implanted to replace your natural lens.

LENS:
The different parts of the Lens are:-

1. Capsule
2. Cortex
3. Nucleus

The primary function of the bi-convex lens is to refract & focus light on retina while remaining transparent. This transparency depends on maintenance of structural (anatomic) & functional (physiologic) integrity.

The lens is 66% H2O, the least hydrated organ of the body, the remaining bulk is composed mainly of mainly of protein. It is devoid of any blood supply & derives its nourishment from surrounding aqueous & vitreous.

CLASSIFICTION OF CATARACT:
a) Morphological: Types

1. Capsular-focal thickening of lens capsule
2. Sub capsular
3. Cortical -Opacification of cortical fibers
4. Nuclear

b) According to maturity:

1. Immature -scattered opacities are separated by clear zones
2. Mature - cortex and nucleus become totally opaque
3. Intumescent -the lens become swollen by absorbing water
4. Hypermature cataract- mature cataract, which has become smaller & has a wrinkled capsule as a result of leakage of H2O out of lens.
5. Morgagnian cataract -hypermature cataract in which total liquefaction of cortex allows the nucleus to sink inferiorly.

CAUSES OF CATARACT:

1. Age -related cataract: Senile -The cataract occurs as a result of natural aging process of lens fibres which become opaque over a period of time.
2. Traumatic cataract:
   1. Due to direct penetrating injury
   2. Concussion
   3. Electric shock & lightening
   4. lonizing radiation to ocular tumors
   5. Surgical trauma
3. Metabolic cataract- Defect in body metabolism
   1. Diabetes
   2. Galactosaemia -inborn error of metabolism
   3. Calcium disorders
4. Toxic cataract
   1. Steroid induced cataract -As a result of excess intake of oral steroid or putting steroid drops in eye.
   2. Drugs induced: chlorpromazine, Miotics, Busulphan, Amiodarone, gold
5. Secondary cataract: develops as a result of some other primary ocular disease such as chronic inflammation and glaucoma.

DEVELOPMENT OF CATARACT:
It varies from person to person but as a general rule, most cataracts develop slowly over a period of time. A cataract can take months or even years to reach a point where it adversely affects vision.

HOW DO CATARACTS AFFECT NORMAL LIFESTYLE:
One may not be aware a cataract is developing if the size and location of the cloudy areas in the lens are not in the pupillary area. As the cataract progresses, there is deterioration of distance and near vision. One may experience hazy, fuzzy and blurred vision. Double vision may also occur when a cataract is beginning to form. The eye may also be more also be more sensitive to light resulting in glare and making night driving difficult. There may be a need to change the eyeglass prescription in the early stages, which may help temporarily. As the cataract develops further stronger glasses would no longer improve the vision this can lead to imbalance between the two eyes, which may cause headaches. One may also experience poor night vision, poor depth perception, e.g. difficulty in getting downstairs.

METHODS OF EVALUATION OF CATARACT :

1. Visual acuity -checking vision of both eyes unaided & aided with glasses & pinhole vision to know the improvement & get the general idea about macular function of eyes. This will help in prognostic evaluation of visual recovery after cataract surgery.

2. Intra ocular pressure -if raised secondary to cataract, surgery is needed to prevent further complications related to raised IOP.

3. Slit lamp Examination - to know the type of cataract/ opacity / its morphology & etiology, any associated ocular pathology

4. Direct & indirect ophthalmoscopy -dense opacity ( cataract will prevent retinal evaluation)

5. A-scan biometry: to calculate the AL & IOL power for implantation

6. In case of mature cataract wherein posterior segment of the eye is evaluated.

TREATMENT OF CATARACT
There is presently no medical treatment that will prevent cataracts or reverse them once they develop. The only treatment for cataract is their surgical removal. The decision to operate is taken by the patient and the doctor together. This decision is based on the degree to which the cataract is impairing vision and the effect it has on patient's lifestyle. It is the decision only the patient and the doctor can make, as based on the individuals needs. With modern advances in cataract surgery, one does not require to wait till vision drops to finger counting. The sooner the operation is done the better are the results.

There are two treatment options available for cataract:

1. Extra capsular cataract extraction - ECCE-a conventional technique.

   Requires an incision of 10-12mm Clouded lens is removed in one piece A non-foldable lens is implanted Multiple stitches are required More chances of high post operative cylindrical number astigmatism.

   
   

2. Micro-incision cataract surgery - phacoemulsification-a modern technique.

Phacoemulsification is the latest technology in cataract surgery. It is a micro-incisional stitch less operation where cataract is emulsified by ultrasound energy, liquefied & sucked through the phacoemulsifier probe. Then a foldable intra-ocular lens is implanted in the eye permanently. It is least traumatic form of cataract surgery with early rehabilitation & recuperation. Vision restoration is possible in a short period of time. (pictures)

Phaco Handpiece

Advantages of Phacoemulsification:

The operation is atraumatic to the eye

Day care procedure without the requirement of hospitalization overnight.

• Operation is performed by putting local anaesthetic drops without giving any injection in most cases. Hence no patch is necessary after the surgery.
• Least chances of infection
• Quicker healing and recovery
• The patient gets good quality vision within 24-48 hours
• Minimum post-op precautions
• The patient can resume professional work in the shortest possible time.
• One may need to wear glasses only to fine tune one's vision. Although glasses will be necessary for clear near vision.
• One can reimburse the cost for the surgery through Mediclaim.

LENS IMPLANT
During cataract surgery, natural lens of the eye that has turned opaque is removed, resulting in loss of focusing power of the eye. This situation would be parallel to taking photograph without a camera lens - picture would be extremely blurred. When the natural lens of the eye is removed an artificial implant is placed in the eye.

Intraocular Lens (IOL)
IOL may be rigid or flexible. The flexible IOL's are made from either Silicone or Polydroxymethacrylate so that they can be folded to allow insertion through a much smaller incision than rigid IOLs.
Posterior Chamber -(PC) IOL s lie behind the iris & have flexible haptics. Anterior Chamber (AC) IOL s lie in front of iris & have flexible or semiflexible angle supported haptics. These are now mainly used if post capsule is accidentally ruptured during surgery.

INDICATIONS FOR CATARACT SURGERY:

1. Visual improvement
2. Medical indications are those in which the presence of a cataract is adversely affecting the health of the eye e.g lens induced glaucoma
3. Cosmetic indications -A mature cataract in an otherwise blind eye is removed to restore a black pupil.

HOW DO I DECIDE WHETHER TO HAVE A CATARACT SURGERY?
Tell your doctor how your cataract affects your vision & your life, you & your doctor can decide accordingly

1. I do not see well enough to do my best at work.
2. I do not see well enough to do things I need to do at home.
3. I do not see well enough to do things I like to do (e.g T.V; sew, play cards, go out with friends)
4. I am afraid I will bump into something or fall.
5. I am not as independent as I would like to be.
6. My glasses do not help me see well enough.
7. My eyesight bothers me a lot.
8. Driving is a problem - too much glare from sun, headlight.

BENEFITS & RISKS OF CATARACT SURGERY:

BENEFITS

Improvement in activities - driving /reading /working /social activities/ hobbies

RISKS
Some of the possible complications are:

1. High pressure in the eye
2. Blood collection in the eye
3. Infection
4. RD (Retinal detachment)
5. Swelling /clouding or cornea

REMEMBER:
Freedom from blurred vision gives you the freedom to enjoy your life to its fullest extent!!

What you should know / do before going for surgery
General health status should be known. Any active diseases should be treated before surgery. Preoperative investigations like blood tests, ECG, Glucose recorded.

Carry out the pre-operative instruction as per the scheduled date & time.

PRE-OPERATIVE INSTRUCTIONS:

1. To have light breakfast 4 hrs before arriving at the hospital.
2. To put the eye drops as instructed 3 day prior to the date of the surgery & in the morning of the day of surgery in the eye to be operated.
3. To take the dose of regular medication which you are already taking.
4. To take head bath and dress comfortably.
5. To be accompanied by not more than 2 persons.
6. To carry the operation file, reports, sunglasses and necessary medication.
7. To register at the reception counter for admission.
8. To read and sign the consent form for the operation and take instructions form the optometrist.
9. If for some reason you have any questions, the doctor or one of the optometrist would be able to answer them before the surgical treatment is begun.
10. To stop blood thinning or any anti-inflammatory medications including Aspirin 3 days prior to the surgery day.
11. Plan to have someone drive you home following surgery.
12. Plan to have a parent or legal guardian with a disabled person.
13. If any change in appointment, call up at the center & inform a day prior to the date of operation.
14. Wear comfortable clothes.
15. Do not apply make-up or wear jewellery.
16. Do not carry expensive goods with you.

Area of operation:
The assistant will take you to the area where you would be prepared for the surgery. You will change into surgical clothes, cap, etc.

Pre-operative medication will be administered by way of anaesthetic drops, injections or sedatives if necessary. One person will help you to enter the operating room and lie down on the operation table, you will always have someone by your side to assist and help you during the operation.

Surgical wash:
The two eyelids will be carefully cleaned with the anti bacterial solution and drops will be put to clean the eyes and to make the area sterile during the surgical procedure.

After surgery:
The assistant will help you to leave the operation theatre and go to the recovery room where you will need to rest for some time. After this, the person who has accompanied you, can take you home to rest.