Abstract
Purpose::
To assess if there are changes on IOP and ocular rigidity (E) at 30, 90, 180 and 720 days in eyes that underwent Lasik surgery (LS).
Methods::
The ocular rigidity before and after LS was assessed by differential tonometry (the 5.5 and 10 gm. weights of Schioetz tonometer - ST) in 23 eyes. We also assessed the volume of corneal indentation (Vc) and IOP with the ST resting on the eye (Pt).
Results::
The IOP measurements by Goldmann tonometer (GT) after 180 and 720 days showed lower values than those at preoperative period. No difference was found between the IOP values at 180 and 720 days. Surprisingly, no difference was found among the IOP (except for RE at 30 days) measurements by ST at any period. The Vc variation was high with a statistically significant difference in all comparisons, including between 180 and 720 days. In relation to ocular rigidity (fundamentally dependent on Vc and Pt), we found that Pt was statistically different (except in LE at 180 days) in all comparisons. The IOP, Vc, Pt and E values were stabilized at 180 days, then, their values did not change at 720 days.
Conclusions::
The differential tonometry did not show differences on IOP measurements pre and post LS at 90, 180 and 720 days. The measurements with GT showed statistically significant lower values. LS significantly induced an increase of the Vc values and a decrease of Pt values and of the ocular rigidity but the Schiotz tonometry with the weights of 5.5 and 10 g perfectly corrected the determination of IOP. No statistically significant change was found in IOP parameters at 180 days. If our data are confirmed by subsequent papers the differential tonometry is reliable to measure the IOP in patients who underwent LS.
Keywords: refractive surgery • refractive surgery: LASIK • intraocular pressure