Intraocular Pressure After Refractive Surgery
We read with great interest the article by Sales-Sanz et al1 comparing different devices to measure the intraocular pressure (IOP) in eyes that underwent laser in situ keratomileusis (LASIK).
We would like to congratulate the authors for their nice and interesting paper, because the topic of IOP measurement after refractive surgery is a very important one; several methods have been published to try to overcome this problem,2 but we would like to make some comments on this article, as in our opinion there is a point that needs to be clarified.
In the discussion the authors stated that to the best of their knowledge their paper was the first to evaluate Schiotz tonometry (ST) in eyes that underwent corneal refractive procedures.
May be this phrase should be corrected. It would be more appropriate if it were worded as “ST in eyes that underwent LASIK,” because in 2008 we reported the accuracy of ST in eyes that underwent photorefractive keratectomy (PRK).3 In this paper, we found that in PRK patients, ST with a 5.5 g load was more accurate than with a 10 g load or with the Friedenwald nomogram; however, although ST seems to be more accurate in measuring the true IOP in patients who have undergone PRK compared with the Goldmann technique, it cannot be considered to be accurate in a sufficient number of cases, concluding that IOP measurement after refractive surgery is still a problem, and further studies are needed to overcome it.
The difference between these 2 studies could be related to the different refractive procedures involved: PRK and LASIK.