Cataract is the most common cause of blindness worldwide. It is fully correctable with complete recovery of vision on treatment in large majority of patients.
What is Cataract?
An eye acts like a camera. Light rays entering the eye are focused by cornea(the clear, dome-shaped surface that covers front of the eye) and the crystalline lens onto the light sensitive tissue, retina. The image created at level of retina is transferred to brain via optic nerve, where the image is analyzed.
In normal young individual, the crystalline lens is transparent. When the lens starts becoming opaque it is known as Cataract.
What causes Cataract?
In majority of people Cataract is an age related change. Exposure to ultraviolet radiations in sunlight increases risk of cataract formation. Age related cataracts are seen even in people in their 40s and 50s. Presence of diabetes mellitus and other systemic diseases increase risk of cataract formation.
Cataracts are also seen in certain congenital conditions; due to trauma; secondary to inflammation in the eye etc.
- Cloudy or blurry vision.
- Colors seem faded.
- Glare. Headlights, lamps, or sunlight may appear too bright. A halo may appear around lights.
- Poor night vision.
- Double vision or multiple images in one eye. (This symptom may clear as the cataract gets larger.)
- Frequent prescription changes in your eyeglasses or contact lenses.
- Often there is improvement in near vision in early stages of cataract known as ‘second-sight’.
What is the treatment available for cataract?
Surgical removal of cataractous lens and replacement with transparent artificial intraocular lens (IOL) is the only definitive treatment of cataract. In early stages of cataract vision may be better by increasing ambient light and change in glasses or contact lenses. But eventually surgery may have to be resorted to.
When is cataract surgery done?
There is a common misconcenception that cataract surgery should be done only after cataract has matured. This is not so. With advances in cataract surgery, it is very safe to remove immature but visually significant cataract.
- Whenever a particular patient feels that his vision poor and interferes with his day-today activity, he/she can undergo cataract surgery.
- Sometimes cataract surgery is performed as cataract interferes with treatment of retinal diseases like diabetic retinopathy or age related macular degeneration.
- In certain types of glaucoma (angle-closure glaucoma), when lens is very intumescent, cataract surgery is performed to open angle outflow pathway.
What tests are required prior to surgery?
- Detailed eye examination including visual acuity testing, intraocular pressure measurement, retinal examination after papillary dilatation, syringing is done to make sure that there are no other eye diseases and that it is safe to perform the surgery.
- If any other disease, other than cataract is suspected, additional tests like OCT, perimetry or fluorescein angiography etc might be performed.
- Calculation of intraocular lens power accurately in essential to get perfect spectacle free vision post operatively. ‘IOL Master’ by Zeiss inc is the based on laser technology that gives accurate IOL power. For certain other patients ultrasound based A-Scan machine (Axis-II by Quantel Technologies) is required. All these types of equipments are available at Dr. Bapaye Hospital.
- Every patient has to undergo detailed physical evaluation and blood tests by Physician to rule out any generalized disease or focus of infection.
What are different methods of cataract surgery?
Extracapsular surgery (ECCE): A longer incision on the side of the cornea and removes the cloudy core of the lens in one piece. The rest of the lens is removed by suction. Since the incision is very large it requires sutures for achieving closure. It may take upto 6 to 8 weeks for complete recovery.
Once the core of cataract is removed, a thin wraparound layer of original lens is left behind known as capsular bag. An artificial IOL is implanted in this , avoiding the need to wear thick glasses. Almost all patients getting operated at Dr.Bapaye Hospital receive foldable acrylic IOLs. The IOL is inserted in the eye in folded form. The lens opens inside the eye. Because of this the lens can be injected through very small incision of phaco and there is no need to enlarge or suture the wound. There are many advances in IOL technology as well.
Multifocal IOLs: These lenses are engineered in manner that the objects from different distances are brought to focus on retina. Hence a patient can see objects at different distance without use of glasses or use of very small number. Multifocal lenses are generally implanted in both eyes at a distance of 2 to 6 weeks. It may take upto 3 months for patient to enjoy their vision flawlessly after surgery of the second eye. This is known as neuro adaptation. In this period some patients experience halos of light, especially during evening time.
Toric IOLs: In majority of patients there is slight irregularity in curvature of cornea. This is known as astigmatism. Astigmatism more than 1 to 1.25 Diopter is visually significant to cause distortion of vision which require cylindrical lenses for correction in post operative period. Ordinary IOLs do not correct astigmatism, they only correct spherical component of refractive error. Toric IOLs with their design make to possible to neutralize corneal astigmatism and offer spectacle free vision in post operative period. Toric IOLs are available in monofocal as well as multifocal designs.