Randomised trial of sequential pretreatment for Nd:YAG laser iridotomy in dark irides
- 1Moorfields Eye Hospital, London, UK
- 2Division of Genetics & Epidemiology, University College London Institute of Ophthalmology, London, UK
- 3NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, UK
- Correspondence to Paul Foster, Division of Epidemiology and Genetics, UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK;
- Accepted 28 March 2011
- Published Online First 21 April 2011
Aims To compare iridotomy outcomes in dark irides by 1064 nm pulsed Nd:YAG laser with and without 532 nm continuous-wave Nd:YAG (frequency-doubled) green laser pretreatment.
Methods 30 patients with occludable anterior chamber angles underwent bilateral standard pulsed 1064 nm Nd:YAG laser iridotomy with one eye randomly assigned to sequential pretreatment with 532 nm continuous-wave Nd:YAG laser. Outcome measures were iridotomy patency and complications including haemorrhage and elevated intraocular pressure (IOP).
Results Median pulsed YAG power in the standard treatment group was 37.5 mJ (IQR 25–77) and 22.5 mJ (IQR 14–32) in the sequential treatment group (p=0.0079). Iris haemorrhage occurred in 43% of the standard treatment group and 13% of the sequential treatment group (p=0.0126). All iridotomies were patent at the end of the procedure in the sequential treatment group, while 2/30 in the standard treatment group were abandoned due to significant haemorrhage. Mean IOP at 1 h was significantly lower than pre-laser values in both groups (with magnitude of reduction significantly more in the sequential treatment group). There was no significant change in IOP at 1 week. All iridotomies were patent at last follow-up of median 38.5 months (IQR 32.0–42.3).
Conclusions This study provides evidence that iridotomy with pretreatment using a continuous-wave Nd:YAG laser is safer and more effective than pulsed Nd:YAG-only laser iridotomy for dark irides and should be considered as the preferred technique.
Competing interests None.
Ethics approval This study was approved by the Moorfields Eye Hospital Research Committee and the Moorfields/Whittington NHS Ethics Committee.
Provenance and peer review Not commissioned; externally peer reviewed.