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PATIENT’S WITH VERY HIGH NUMBERS / VERY THIN CORNEA :
Patients cant undergo LASIK surgery if they have very high numbers (usually more than -10 or -11 or more than +5). If such patients still want to get freedom from glasses then the other option is a Refractive Lens Exchange. In this surgery the natural lens is removed by phaco surgery and it is replaced with an artificial lens of adequate power. The advantage is that special lenses such as toric lenses for cylindrical numbers or multifocal lenses for giving bifocal vision can be used. Any amount of spherical number can be corrected so the range of correction possible is vast. The cornea is untouched so the corneal thickness doesn’t matter and hence the chances of corneal complications are avoided. The disadvantages are that it is an intraocular surgery and needs intervention inside the eye. Some numbers (thin glasses) may be required for near work or for accurate work in some cases. However, the dependence on glass is greatly reduced and they would be required only in certain circumstances.
HIGHLY DESHAPED CORNEA :
In cases which have a disease affecting shape of the cornea a surgical procedure like lasik is completely not warranted and dangerous. Moreover such cases are not adequately corrected with either glasses or routine soft lenses. For such cases, the speciality lenses as scleral or mini scleral lenses are a boon. These are custom made lenses made to fit the irregularly shaped cornea. In many cases they also support the weak cornea. By fitting over the cornea, they replace the irregular surface of the cornea and form a new regular surface giving a good quality of vision to the patient.
These lenses can also be used in cases of badly damage cornea such as chemical injuries, severe dry eye, badly done previous Lasik surgery and other corneal defects. |
