Thanks to the flexibility of new laser technology it is possible to intervene and treat visual defects on the entire surface of the cornea. We spoke to Professor Paolo Vinciguerra, Head of the Ophthalmology Center at Humanitas.
Refractive surgery flexibility of laser
A sophisticated laser has the ability to treat the entire surface of the cornea. When we want to treat a visual defect it is good to involve the entire surface of the cornea. If only part of the cornea is treated it may cause impaired vision at night. This is because the pupil widens in darker light and may reach the surface area not treated by laser.
To give an example. A patient who has had the corneal surface treated for myopia will have great vision during the daytime. As evening arrives, the pupil will enlarge and be behind parts of the cornea that have not been treated. Parts of the cornea that are still myopic. In this case, the patient will find himself with two images on the retina. One in sharp focus and a blurred vision from the myopic part.
This is because some lasers have an optical zone that varies from 5 to 6.5 mm width at the maximum. It would be appropriate, instead, to have an ablation that reaches 10 mm and that can reach the full width of a pupil in all cases.
From a recent research carried out it was found that it was difficult even for experts to recognize which eyes had been operated on and which had not. This is because the whole cornea was reshaped. The laser’s flexibility allows you to successfully correct defects which are very complex. In the past many conditions could not be treated, such as high astigmatism.
When these defects are treated with a laser on a small optical zone, they do not have as good stability over time. In fact, results obtained only last in the short term because the problem tends to recur over time.
Refractive Surgery Reprocessing
Sometimes a patient who has undergone a treatment in past years may not be seeing as well as he would like. The laser has a specific program dedicated to repeating the treatment to correct these possible defects.
It is not always possible for re-treatment to completely eliminate defects from previous interventions and at the same time eliminate the use of glasses. Despite this, patients observe a significant improvement in visual quality.