Intraocular pressure variations after diode laser photocoagulation for threshold retinopathy of prematurity*1

Abstract

<h2>Abstract</h2><h3>Purpose</h3> To investigate the intraocular pressure (IOP) variations occurring after indirect diode laser photocoagulation for threshold retinopathy of prematurity. <h3>Design</h3> Prospective, nonrandomized, comparative study. <h3>Participants</h3> A study group—21 consecutive premature babies (42 eyes) undergoing diode laser photocoagulation for retinopathy of prematurity—and control groups—32 premature babies (64 eyes) undergoing retinal examination with or without scleral indentation. <h3>Intervention</h3> Intraocular pressure was measured with a portable electronic tonometer before, immediately after, and 1, 2, and 3 days after diode laser photocoagulation in the study group; before retinal examination in control group 1; and before and after retinal examination with scleral indentation in control group 2. <h3>Main outcome measure</h3> Intraocular pressure after diode laser photocoagulation for threshold retinopathy of prematurity. <h3>Results</h3> Mean IOP in the study group rose from 15 mmHg (standard deviation [SD] = 4.1) before coagulation to 33.2 mmHg (SD = 7.8; range, 20–50) immediately after, and then dropped to 22.2 (SD = 5.2), 16.5 (SD = 3), and 14.5 mmHg (SD = 2.1) 1, 2, and 3 days later, respectively. All the changes were statistically significant at <i>P</i><0.0001, except for the difference between days 2 and 3 (<i>P</i> = 0.096). Mean baseline IOPs were 16.3 mmHg (SD = 3.7) in control group 1 and 15.7 mmHg (SD = 2.3) in control group 2 (<i>P</i> = 0.84 between control group 1 and study group, and <i>P</i> = 0.32 between control group 2 and the study group). At termination of the retinal examination with scleral indentation (control group 2), IOP measured 15.1 mmHg (SD = 2.2) (<i>P</i> = 0.49 compared with baseline). <h3>Conclusions</h3> Intraocular pressure may be significantly elevated after diode laser photocoagulation for retinopathy of prematurity. The mechanism and long-term clinical implications of this observation should be investigated.