Corneal Sensitivity and Pupil Motility in Patients with Retinal Detachment Treated with Vitrectomy and Circumferential Laser Photocoagulation: Comparison Between 810 nm Diode and 523 nm Argon Lasers

Abstract

Purpose: Circumferential intra-ocular laser photocoagulation is indicated in few cases of retinal detachments. It can induce disorders in corneal sensitivity and pupil motility. The primary objective of this study is to quantify the rate and the severity of such complications. The secondary objective is to compare these side effects among the use of the 810 nm diode laser and the 532 nm argon laser.

Methods: In a retrospective study, 33 eyes of 28 patients with retinal detachment treated with vitrectomy and circumferential intra-ocular laser photocoagulation were included as well as 28 control patients, between 2009 and 2011. The treated patients were divided into two groups: argon and diode laser. All patients underwent measurement of corneal sensitivity using a Cochet-Bonnet esthesiometer, ocular surface and pupil examination including slit lamp examination, fluorescein test and anterior segment photography.

Results: Median central corneal sensitivity was 2.75 mm (IQR: 1.31, 4.50) in eyes treated with circumferential intra-ocular laser photocoagulation and 6.00 mm (IQR: 5.50, 6.00) in control eyes (p <0.001). In the diode laser group, corneal sensitivity was significantly lower than in the argon laser group and in the control group (p <0.0001). Superficial keratitis and pupillary abnormalities (anisocoria or altered pupillary reflex) were significantly more frequent in the diode laser group than in the argon laser group and in the control groups (p = 0.05 and p <0.0001 respectively). It seemed that the more recent were the surgeries the deeper were the corneal disorders. These corneal and pupil impairements can be explained by thermal injury induced by the laser at the level of the long and short ciliary nerves in their choroidal pathway. Anterior segment complications induced by the 810 nm diode laser seem more frequent and severe than the 532 nm argon laser. The former produces deeper impacts in the ocular tissu that would more likely damage the nerves.

Conclusions: Circumferential laser photocoagulation impairs corneal sensitivity and pupil motility mostly with the 810 nm diode laser. Using of the 532 nm argon laser, searching for minimal efficient laser power and preserving the ciliary nerves paths during photocoagulation may be useful to avoid these complications.

Keywords: 697 retinal detachment • 578 laser • 668 pupillary reflex