Dr.Ram Nath, MD. (AIIMS)
Senior Consultant Consultant Surgeon and Medical Director,
Advance Laser Eye Cure Centre, Dwarka
Cataract is the disease of human crystalline lens, the primary focusing mechanism of the eye. In normal eye crystalline lens is clear and transparent. As age advances, the lens becomes discolored, cloudy and finally opaque, there by hampering clear vision. Any opacity in crystalline lens is called "Cataract" or "Safed Motia". It is a primarily a disease of old age of 65 years have some form of the congenital cataract. It is estimated that more than 95% of population over the age of 65 years have some form of cataract Other causes of cataract are trauma, metabolic (e.g. Diabetes Mellitus), complicated (e.g.Uveitis), Post-Steroid use etc.
Cataract is the leading cause of blindness worldwide. In India, it accounts for more than 80% of blind persons whose vision is not correctable with the glasses. With progression of cataract, patient vision gets diminished progressively both in quantity and quality. Finally, patients become dependent on others for even routine personal works like going to the toilet or changing their clothes. Depending on degree, type and location of cataract, presentation of cataract varies from minimal awareness of disturbance of vision to a total failure of vision, Patient's both near & distance vision changes, although, in variable proportion. Some patients may notice improvement in vision, albeit temporarily. There could be diminution of vision both in bright and dim light. Patient may find themselves temporarily blind while driving, lead to major accident jeopardizing the lives of patients and others. Patients other complaints include change on perception of color, color halo, polypia etc.
In the absence of proven medical therapy, surgery is the only hope for millions of the cataract patients to regain their vision Cataract is one of the most successfully treated condition by surgery which, with the help of optical aids, usually leads to complete visual rehabilitation, One patient question, which is generally asked by the patients, is "When to get himself / herself operated." Its answer depends on many variables like profession of the patient and his/her visual requirements etc. One can wait for surgery as in the case of sedentary house wife but definitely not in the case of Air-pilot whose slight impairment of vision can cost lives of many co-air-travelers.
Moreover, one should not wait to get his/her cataract to mature. Delay in surgery makes surgical procedures difficult with poor visual outcome. There is risk of developing serious vision threatening conditions like lens induced glaucoma and uveitis too. In general, when cataract begins to affect your vision to the extent where one’s daily life style is disturbed and/ or one's profession suffers, one should now opt for surgery without undue delay.
There are many surgical methods available to deal with cataract. Each method has its own merits and demerits. In earlier days, it was performed by surgeons who used to dislodge the cataractous lens in the vitreous cavity by mechanical means, thus clearing the visual axis (couching: a method full of hazards and complications). Then came the era of Intra capsular cataract extraction (ICCE) where in whole lens was removed by various techniques in one piece, leaving behind no remnants of lens. Initially, it was done without sutures. With the arrival of good quality of sutures, suturing of wound became routine procedure along with the cataract extraction. All these procedures, although very useful as far as visual gain was concerned, were associated either longer stay in the hospitals, immobilization of patients, delayed wound healing and poor visual rehabilitation(due to use of high plus glasses.)
Moreover, there were high risk of developing serious post operative complications like retinal detachment and macular edema- all can lead to permanent visual loss. To minimize these serious complications, Surgeon started extra capsular cataract extraction(ECCE) in which whole posterior capsule along with part of anterior capsule were left intact in the eye at the time of cataract extraction. It was a very good improvement over intracapsular cataract extraction. Patient, however, was not satisfied lot they were having no option, but to use high plus glasses for their visual rehabilitation. The high lens can produce a lot of distortions of image and bizarre visual sensation due to inherent drawbacks. With the advent of microsurgical procedures and arrival of good quality of intra ocular lens (IOL), scenario had drastically changed for good. Now near normal vision is possible, after cataract extraction and posterior-chamber (P/C) IOL implantation.
With the better understanding of wound healing wound construction & design and simultaneous development in the field of machine and Intra-Ocular lens, an era of phacoemulsification with foldable in-bag IOL has come to stay. This is the most modern for cataract removal and visual rehabilitation. This technique in Common man language is also called stitch-less cataract surgery. Some may refer it to laser cataract surgery, although, no laser energy is progressively fragmented in microscopic pieces, emulsified and sucked out by ultrasonic prone enables surgeon to perform cataract surgery ,although, no laser energy is being used. In phacoemulsification cataract lens is progressively fragmented in microscopic pieces, emulsified and sucked out by ultrasonic probe which tip vibrates 40,000 per sec. or more at frequency of wound. Smaller dimension of ultrasonic probe enables surgeon to perform cataract surgery with minimal width of wound incision.
Previous Intra-Ocular Lenses (IOL) is made up of PMMA, a non-foldable plastic, where in a minimum of 6.5 mm corneo-scleral incision is required. Such a large conventional Corneo-scieral incision was not self sealing wound thus necessitating suturing. Same time development in IOL design, its material and its insertion techniques has made possible to implant foldable IOL in eye through an incision size as low as 2.0 mm width. Foldable IOL are usually made up of silicone and acrylic which are being inserted through with the help of either special kind of forceps or injectors. Last, although foremost, important development in the field of stitch less cataract surgery is evolution in marvellous architectural design of wound construction which is called "Self-sealing tunneled incision" thus eliminating the need of suturing. Term Phacoemulsification and stitch less cataract surgery, although, are used interchangeably both are not the same. One can perform a stitch less cataract surgery without using phaco-emulsification. One contrary, a surgeon, where in a self sealing wound is in-doubt may use one or two stitches following phacoemulsification to ensure safety to patient's eye.
Extraction of cataract by phaco-emulsification technique with implantation of foldable IOL has many benefits to offer, both to the surgeons and patient. This has prompted many surgeons worldwide to shift from conventional way of dealing cataract to phaco-emulsification. In U.S.A. more than 95% of surgeons prefer to operate cataract by phaco-emulsification, where as in India it is mainly performed in big cities .