Discover how to correct the most fastidious of visual defects with corneal refractive surgery
What it is
Refractive surgery with the excimer laser is a safe, effective and definitive surgical technique that corrects refractive defects such as myopia, hypermetropia and astigmatism. An eye examination is essential to verify the actual visual defect of the patient. During this examination a series of instrumental diagnostic exams are carried out, with the aim of verifying the suitability of the patient for the operation. The excimer laser, now it its fifth generation, emits an ultraviolet beam with very high energy but very low penetrating power in the biological cells, which allows for a vaporisation of the corneal tissue in a targeted manner. The laser action is entirely controlled by a computer, which executes in nanometric detail the data inputted by the surgeon. The correction techniques differentiate because of the preliminary preparation to the action of the laser.
An accurate evaluation of the patient is essential for a good result of the refractive treatment. During the pre-refractive visit, the surgeon investigates the motivations and the expectations towards the operation. In particular, specific professional and personal motivations are taken into account. By analysing the pathological and ocular case history it is possible to verify the general state of health of the patient, the existence of previous eye illnesses that could make a refractive operation impossible, as well as previous or ongoing pharmacological therapies or therapeutic treatments. After this phase, a thorough eye examination is carried out, which includes: the examination of the severity of the refractive defect (subjective refraction) and examination of the refraction in cycloplegia, to exclude the accommodative component of the crystalline lens that can affect a correct evaluation. The instrumental routine exams are: tonometry, pachymetry, corneal topography, pupillometry. Other examinations that can be carried out are: endothelial microscopy, biometry, aberrometry. After acquiring all this information, the surgeon explains which type of surgery is most suitable for every single case and clearly presents the aspects of the operation and answers the patients’ questions.
In the PRK technique the excimer laser acts on the corneal surface and reshapes the corneal curvature based on the type and seriousness of the visual defect. The operation is carried out on both eyes, lasts a few seconds and only some collyrium anaesthetic drops are required. After the treatment, the surgeon applies antibiotic collyrium drops and applies a soft contact lens to favour regular re-epithalisation. This lens will be removed once the scar tissue process has finished. In the post-operating phase it is very important that you adhere to the specialists’ indications. Straight after the operation, the eye is kept open and, despite some discomfort (due to light sensitivity) and some burning sensation, it is able to see. Optimal recovery is progressive and from the very first days you can take up your ordinary activities once again. Full recovery is subjective and is checked by the ophthalmologistz. It usually takes one or two months.
It is a variation of PRK. The epithelium is not removed, but is raised and refolded after being soaked in an alcoholic solution. After the laser's work, it is unfolded again and replaced with no sutures. This technique accelerates the growth of the epithelium, even if the post operating phase and the recovery time are similar to those of PRK.
In the LASIK technique the excimer laser works inside the cornea. It is nowadays the most common procedure in the world. The surgeon uses a femtoseconds laser to create a thin zip section of the cornea called “a corneal rim”. Once this rim is raised, the excimer laser is used to correct the refractive defect. At the end of the procedure the rim is replaced with no need for sutures. The patient can go home wearing dark glasses. FEMTOLASIK, apart from being a technically more complex operation, is different from PRK and LASEK, mostly in the post-operating phase, which is quick and almost always painless. Straight after the operation, the eye does not show particular disorders and this allows for a quick functional recovery from the very first hours. Vision keeps on improving and usually settles down into a stable state after a few weeks.
During the fist day one should not strain one’s eyes: it is not necessary to stay in the dark, but obviously one should avoid activities where the eyes are strained (computer, television). It is absolutely essential, however, to strictly follow the surgeon’s indications regarding both the post-operating therapy and the checks in the post-operating phase. Moreover, it is also advisable to protect the eyes with sunglasses in the months that follow.