Safety of intraocular pressure measurement using air-puff tonometer after implantable collamer lens implantation

Abstract

To determine the safety of intraocular pressure (IOP) measurement using a noncontact tonometer in patients who have undergone implantable collamer lens (ICL) implantation. Eye, Ear, Nose, and Throat Hospital. Prospective study. 64 eyes of 33 patients (aged 28.4 ± 5.2 years) scheduled for ICL implantation were enrolled. The anterior segment parameters and vault were obtained using an anterior segment analyzer. A noncontact air-puff tonometer was used preoperatively and at 1 day and 1 week postoperatively to assess corneal biomechanical properties and IOP. The Corvis ST was used to evaluate the distance between the corneal endothelial layer and iris (E-Iris Dist) and the distance between the corneal endothelial layer and ICL (E-ICL Dist) when the cornea was deformed by the airflow. The mean anterior chamber depth (ACD), anterior chamber volume (ACV), and anterior chamber angle (ACA) decreased significantly postoperatively (all P values <.001). The E-ICL Dist values measured 1 day and 1 week postoperatively were similar ( P = .107). However, a contact between the corneal endothelium and ICL was detected in 2 eyes when the cornea was deformed to the highest concavity. The 1-day postoperative vault, ACV, ACA, and preoperative stress-strain index contributed significantly ( P = .001, P = .023, P = .010, and P = .019, respectively) to determine the distance. The mean E-iris Dist values decreased significantly at 1 day and 1 week postoperatively ( P < .001). The 1-week postoperative vault and ACD contributed significantly ( P = .025 and P = .039, respectively) to determine the E-Iris Dist value. Excessively high vault, shallow ACD, narrow ACA, low ACV, and soft cornea are associated with a lower E-ICL distance and thus may be risk factors for a contact between the corneal endothelium and ICL during IOP measurement. Although there is no proof that the contact may cause any risks to the endothelium, noncontact air-puff tonometry should be avoided in eyes predicted by the study model to be at risk of this occurring. Contact IOP measurements using Goldmann applanation tonometers or dynamic contour tonometers may be alternate methods of IOP measurements in extreme cases.