Posted on October 25, 2017
There are several safe and effective surgical options available to eliminate dependence on spectacles. Despite that LASIK for high myopia remains a challenging task for even the most competent eye surgeon. Typically, traditional laser eye surgery is known to be effective in correcting prescriptions up to a maximum of between -10 and -12 dioptres.
However, the commonly held belief that laser eye surgery is not an option for those with very high prescriptions, is now proving to be false, with better technology being available for laser vision correction. Selecting the safest and most appropriate technique for each patient and customising solutions to best fit the requirements of the patient has made favorable outcomes possible even in patients who were earlier considered clinically unsuitable for LASIK.
The treatment possibilities are now expanding, and currently available technologies that have revolutionised the treatment of high myopia include:
1. Sub Bowman’s Keratomileusis, SBK with custom Q: It is a special type of LASIK in which the corneal flap is thinner. Femtosecond SBK employs an infrared beam of light to make an ultra-thin flap (much thinner than the flap created during conventional LASIK). A corneal flap can also be created with a microkeratome, the blade that is used in conventional LASIK. Since the flap is thinner, it means that a higher degree of myopia can be treated effectively and safely.
2. Femtosecond Laser: The femtosecond SBK/ LASIK flap is much thinner and more precisely made than the traditional LASIK flap, which means that laser correction takes place much closer to the surface, as in a surface ablation procedure like PRK. With a thinner flap, approximately 90 microns, versus 150 microns for standard LASIK, leaves sufficient stromal tissue to allow for safer excimer laser ablation, especially in patients with moderate and high myopia reducing the risk for causing complications after surgery.
3. ReLEx Laser Eye Surgery: This treatment has really expanded the group of patients who can undergo laser vision correction, with powers greater than -10 dioptres also being easy to treat. In this procedure no flap is made, but some corneal tissue is removed from the centre of the cornea through a tiny hole made at the side of the eye, leaving the corneal surface intact.
ReLEx SMILE laser eye surgery uses the precise laser beam to create micro-pulses beneath the surface of the cornea, which ablates the tissue. Because the technique does not require a corneal flap being made, the incidence of dry eye after the procedure is reduced significantly.
4. Contoura Vision Topography-Guided Laser Correction: Contoura Vision is a type of laser vision correction surgery that maps the unique topography of the eyes of each patient. Topography-guided ablation has revolutionised vision correction because it is the only procedure of all refractive surgeries that treats the problems being caused by corneal irregularities also. In the US FDA trial the treatment was reported reduced visual symptoms such as glare, halos and starburst. They actually improved the best corrected visual acuity; that is, about 33 percent of patients actually saw better than they did with their glasses before surgery.
In patients who are not eligible for even these procedures, there are still several surgical options available for freedom from glasses.
- Refractive Lens Exchange, RLE: RLE involves removal of the natural crystalline lens of the eye with phacoemulsification, as for cataract surgery, and replacing it with an IOL. This is a very effective option for the treatment of high myopia, especially in patients over 50, or those with early cataract.
- Phakic IOL: These are lenses implanted within the eye through a small cut on the surface of the eye. These lenses are called iris-claw lenses, and are clipped on the brown/black, blue part of the eye, called the iris. These remain a surgical option for younger patients who do not wish to have their natural lens removed.
- Implantable Collamer Lenses, ICL: The ICL is an artificial lens, which acts like a contact lens, and is implanted inside the ye like an intraocular lens. The ICL is implanted in front of the eye’s natural lens, in the space behind the iris, and is completely invisible to observers. The ICL procedure has been approved by regulatory authorities for the correction of moderate to severe myopia up to -20.0 dioptres.
With current advances in surgical and diagnostic technologies, many patients who were earlier considered unfit for LASIK can be offered laser vision correction now, which is safe and effective. In the small group of patients where ever these advanced surgical procedures are not advisable, the other surgical options available can still provide freedom from glasses safely and effectively. Each of these surgeries, of course, have to be customised to the needs of the individual patient, and the doctor’s proficiency with the available machines.