LASEK, PRK and Epi-LASIK techniques
The LASEK, PRK and Epi-LASIK laser techniques are methods of refractive vision correction surgery that are used to smooth the cornea on its surface. Because this type of surgery does not require a micro surgical incision in the cornea, the techniques are appropriate for those individuals who have a thinner cornea. PRK is a classic, 'first-used' laser method. The most up-to-date techniques are currently LASEK and Epi-LASIK. In all of the three methods, the upper layer of epithelial cells is removed prior to surface laser smoothing. The difference between the techniques lies only in the method of removal, which does not influence on the surgery itself or on its result. After laser corneal smoothing, the area is again covered with the previously removed layer of epithelium, which serves to protect the surface of the cornea and positively influence on its recovery after surgery.
Advantages and disadvantages
The advantages of techniques that use surface laser smoothing of the cornea are that they preserve the biomechanical shape of the cornea intact and are substantially less technically demanding due to there being no microsurgical incision in the cornea. Disadvantages are that the restoration of visual acuity is slower after surgery and that the patient often feels an unpleasant burning sensation on the first day after surgery. In some cases, the techniques of surface laser ablation also results in greater cornea scarring. After these procedures, three to four days are normally required to restore good visual acuity, while the final result of full visual acuity can be expected after one month.
Surgery and recovery
Surgery lasts from 10 to 15 minutes, is performed under local (eye drop) anaesthesia and is completely painless. Immediately upon returning home, it is obligatory to start infusing antibiotic and corticosteroid drops in prescribed dosages. During the first several days after surgery, it is recommended that the patient rest without placing major strain on the eyes – for example, avoiding reading for a long period of time, working on the computer or watching television. After surgery, it is possible to be a little more sensitive to strong light, the patient may experience glare and the operated eye may be more teary than usual. The patient must not rub his or her eyes or stay in dusty or smoke filled areas. He or she must also not drive until vision is completely restored.
It sounds complicated, and if we wanted to explain all the details, it is, but the basic principles of this technique can also be described in a relatively simple and comprehensive manner. The word Wavefront can literally be explained as a frontal wave, a principle that is well known in the field of optical physics, a science that is concerned with the bending of light. Wavefront analysis measures changes in the wavelength of light as it is sent through a type of medium.
Refractive vision correction with intraocular lens implantation is similarly as successful and reliable as laser surgical procedures but is due to its somewhat more limited indications not as widely used or as well known. This procedure of refractive vision correction is performed by implanting an artificial lens into the eye and is also successful in refractive vision correction in patients with a high dioptre as well as in patients whose cornea is too thin to be suitable for laser surgery.
Age-related farsightedness can successfully be treated with the insertion of a special, multifocal lens that enables good near and far visual acuity. The best results of this type of surgery are achieved in patients in which age-related farsightedness appears alongside an already present refractive error, regardless of whether this is nearsightedness or farsightedness.