LASIK surgery is used for astigmatic correction as well as simple myopia by the use of the excimer laser. An excimer laser corrects simple myopia by restructuring the Cornea. Greater laser energy is applied to the central cornea as compared to the peripheral cornea usually accomplished by closing or opening a circular aperture or alternatively by using a scanning laser to focus the pulses on the central region. The final result is a convex surface caused by the central stroma of the Cornea getting more laser energy than the peripheral region.
On the other hand Hyperopic correction is achieved by focusing more laser energy on the peripheral regions of the cornea as compared to the stromal region. This creates a concave surface caused by the central stroma of the Cornea getting less laser energy than the peripheral region. Myopic Astigmatism is corrected by applying the laser energy in an elliptical pattern in the central region of the flat meridian. This enables the flattening of the steep axis. In the same way hyperopic astigmatism is corrected by applying the laser beam in the peripheral region, thus steepening the flat axis.
The most common type of laser, which is used for effecting the restructuring process is one with a wavelength of 193 nm, which removes approximately 0.25 µm of stromal tissue with each pulse. If greater correction is needed more tissues are removed.
There are some basic differences between LASEK or laser epithelial keratomileusis and LASIK surgery. Even though the calculations and the ablation methods are the same, the main difference between the two techniques is the depth within the cornea where the laser energy is applied.
In LASIK surgery the Laser energy is sent in the midstromal layer after the LASIK flap is created and the stromal layers are exposed. In PRK, the removal of tissue occurs in the Bowman layer and anterior stroma rather than in the midstromal region. IN LASEK surgery the epithelium is retained as a sheet and then placed over the ablated area after the process has been completed.
The last few years has seen the development of quite a few advances in LASIK surgery. Techniques have been perfected to collect refractive data, which enables correction of not only myopia, hyperopia, and astigmatism but also higher order refractive anomalies. One such technology is the Wavescan Digital technology, which was originally developed for astrophysics to correct distortion of images by atmospheric interference. The same technique is now used to correct higher order spherical aberration, and astigmatism.
One of the most qualified and highly regarded Lasik Surgeons in the US is Dr. Kevin Niksarli who is synonymous with the Lasik Surgery techniques. Lasik Surgery is widely used today due to its innate benefits as compared to conventional forms of eye surgeries.
Dr Kevin Niksarli is an authority in Corneal and Refractive Surgery, and is also the Founder and Medical Director of Manhattan LASIK Center. Dr. Kevin Niksarli has successfully accomplished more than 70,000 successful LASIK eye surgeries, which he has completed in an ultra modern Manhattan Lasik Center, which he has carefully mentored and is now regarded as one of the finest eye hospitals in present times.