Although commonly considered safe and effective, the LASIK surgery still has its limits even when performed by an experienced LASIK surgeon. In Singapore, like many other countries, LASIK has become the most popular eye surgery; but that still does not mean that LASIK works well on all levels of Myopia.
LASIK is most effective when treating myopia from -1.00 dioptres to -8.00 dioptres (i.e. 100 to 800 degrees). Treatment above this power is associated with less predictable results and higher complication rates. This is because beyond -8.00 dioptres of correction, a greater amount of cornea tissue must be sculpted and this will begin to thin the cornea to its safety limits. Current treatment guidelines require that at least 250 microns or a quarter of a millimetre thickness of cornea must be preserved beneath the flap if cornea complications are to be avoided. For this reason, your doctor will measure your cornea thickness prior to the surgery to determine the safe limits of myopia correction.
A power of -12.00 dioptres (1,200 degrees) is usually taken as the upper limit of safe LASIK treatment by most doctors. Above this power, many eye surgeons will instead advise an Advanced Surface Ablation (ASA) procedure such as Safe TransPRK or intra-ocular lens implantation as the procedure of choice. In this case, a small wound is made at the side of the cornea and an artificial lens, made of plastic, silicone or acrylic material, implanted permanently inside the eye.
The artificial lens is placed either in front of the natural crystalline lens or in its place. Visual recovery is rapid and painless with the eye seeing well the next day.
The results of the LASIK surgery depend on your personal conditions and healing progress of the eye, managing your expectations prior to the surgery remains a critical part of the surgery preparation. Should the results turn out to be far from expectations, in some cases, your doctor may suggest a second “enhancement” surgery to fix the over or under-correction. The time between the two surgeries varies from person to person, once again, depends on the personal health condition and the healing progress of the eyes. It is important that you don’t rush into anything before having a proper discussion with your doctor and receiving the permission to undergo another eye surgery.