What is Cataract?
Cataract is opacification /clouding of the transparent crystalline lens of the eye. This opacification obstructs light from being transmitted to the retina causing blurring of vision .
What causes cataract?
Most cataracts occur as a result of increasing age. The normal process of aging causes the lens to harden and turn cloudy.
Other causes of cataract are:
Injuries, infections, certain medications, previous eye surgeries, long term exposure to UV light, diseases like diabetes and congenital(by birth) are amongst the common causes.
What are the symptoms?
Clouding of vision, distortion of images, double vision in one eye, frequent change of glasses, increased sensitivity of eye to light and glare and difficulty in night vision are commonly noted.
What is the Treatment for Cataract?
Surgery is the only way to treat a cataract. Following are the surgical techniques for cataract removal:
Intracapsular Cataract extraction: very rarely done nowadays.
Extracapsular Cataract extraction: entire lens physically removed leaving a capsule for supporting lens.
Phacoemulsification: lens broken into parts using ultrasonic energy and sucked out thro a special needle. Most cataract surgeries today are done by phacoemulsification.
Advantages of Phacoemulsification over other techniques:
Sutureless surgery, faster visual recovery, returns home within hrs of surgery, final spectacle number is smaller and more predictable with less astigmatism.
Surgery is combined with implantation of an intraocular lens.
IOL’s can be rigid (PMMA) or foldable. Foldable lenses which are preferred these days may be of different varieties. You may discuss the appropriate variety for you with your doctor. Newer lenses such as aspheric lenses, Toric lenses, Multifocal lenses
Kinds of IOL
There Are Basically 2 Kinds Of IOLs Used: FOLDABLE And NON-FOLDABLE
They are made of PMMA material. The oldest IOLs to be developed. Are still in use as are highly economical. Most commonly used in eye camp surgeries or in low budgeted patients. They are also used in some complex situations where FOLDABLE lenses are not indicated. The size of cataract wound has to be extended to 5.1 to 6.1 mm to be able to implant them.
They are made of either ACRYLIC or SILICONE material. These are modern day lenses. They have gained immense popularity since the time of introduction of PHACOEMULSIFICATION technique to remove cataract. In write up on cataract surgery, there is a mention on the incision size in PHACO of 2.8 to 1.8mm. These FOLDABLE IOLs can be implanted thru the same incision size. In our country ACRYLIC is more commonly used than SILICONE.
Properties Of An IOL
360 square edge design: this helps in prevention of formation of after cataract what we call as posterior capsular opacification or PCO.
ASPHERIC: the IOLs that are implanted do have a tendency of having a slight shift of micro mm from their original position in the first few months. ASPHERIC property takes care of that and retains the vision clarity.
ABERATION CONTROLLED: our cornea has a few micro irregularities that can be counter balanced by an IOL having this property.
This helps in sharper and crisp vision.
YELLOW IOL: some experts state that they block a particular range of U-V light there by helping to prevent degeneration of macula. Although this property is debatable, since implanting a yellow IOL has no negative effect on visual outcome, many doctors have accepted this technology.
All these properties in an iol help in a better vision outcome following cataract surgery. All these properties may or may not be available in all the iols. Please consult your ophthalmologist for more information.
New Generation Iols:
ACCOMMODATIVE/ MULTIFOCAL : The above IOLS provide clear vision for distance only. But these new generation IOL help in all distances i.e. distance, intermediate (like computer usage) and near. Although they may not be ideal for all, your consultant will be the best to judge for you.
TORIC IOLs :Some patients have a pre-existing cylinder number. If pre-existing cylindrical number is higher than 1 or 1.25 diopter than TORIC IOLs can nullify the number or else you may still be compelled to use glasses following the surgery.
When should one get operated?
Surgery should be considered when there is enough loss of vision to cause interference with routine day to day activities. It is myth that a cataract needs to be “ripe” to be operated. Based on individual needs patient and doctor should decide the timing of surgery.
What can happen if the cataract is not removed?
If not operated the cataract matures (becomes more cloudy) causing progressive and ultimately complete loss of vision. When fully advanced, lens material may cause increase in pressure of eye (glaucoma), and intraocular inflammation. The lens may lose its natural support and move from its position. This can cause permanent damage to the eye. Surgery in these cases is also difficult and complicated with unpredictable results.
What to expect after a cataract surgery?
Cataract surgery is a highly successful procedure. There is significant vision improvement unless there is problem with the cornea, retina, optic nerve or other intraocular structures. Sometimes it may be difficult to diagnose the abnormalities before surgery due to the cataract. We can know about it only after the surgery. In many people post cataract surgery, the natural capsule that supports the IOL becomes cloudy. This can be opened with a simple OPD laser procedure to restore vision.
Are glasses required after cataract surgery?
With the advent of multifocal and toric lenses and accommodating lenses are leading to increase independence from glasses after surgery. Your eye surgeon will guide you about your suitability for these IOLs depending on our visual requirements and the condition of the eye.
How much visual recovery to expect?
Cataract surgery has a very high success rate , over 95% cases are successful .However it is important to realize that even after a successful cataract surgery visual recovery depends on the condition of the eye i .e. retina, optic nerve,any preexisting disease,, amblyopia etc.