LPIp and LPI procedures
palpebral fissure, atrophy
ATROPHY
The enrolled patients were treated with LPIp combined with LPI after AS-OCT and Pentacam (70700, Oculus) scanning. One hour before the laser treatment, 2% pilocarpine nitrate eye drops (Bausch + Lomb, USA) and tobramycin dexamethasone eye drops (Alcon, USA) were alternately applied three times per eye drop with an interval of 5 min. Obucaine hydrochloride eye drops (Santen, Japan) were used for surface anaesthesia before treatment. First, LPI was carried out at the recess or the thinnest part of the iris, while avoiding the palpebral fissure area, using an Nd:YAG laser (Selecta Duet, LUMENIS) beam of about 0.2 mm in size. Then, LPIp was performed using an argon multi-wavelength fundus laser (Vision One, LUMENIS). Fixed parameters were a spot area of 500 μm and an exposure time of 0.7 s. The laser range comprised 16 points distributed over 360 degrees. Laser energy and spot location were variable parameters. Two levels of laser energy (high energy, dark grey indicating obvious atrophy; low energy, light grey indicating light atrophy) and two types of spot positions (far from the periphery, 2 spot diameters from the scleral spur; near the periphery, 1 spot diameter from the scleral spur) were randomly assigned to each patient through random envelope method, dividing the study population into four treatment groups. Group HEFP: high energy, far from the periphery; group HENP: high energy, near the periphery; group LEFP: low energy, far from the periphery; and group LENP: low energy, near the periphery. Postoperative medication included tobramycin dexamethasone eye drops (4 times/day for 1 week) and 2% pilocarpine (once per night for 3 weeks).