Association of raised intraocular pressure and its correlation to the energy used with raised versus normal intraocular pressure following Nd: YAG laser posterior capsulotomy in pseudophakes.

Abstract

To determine the frequency of raised intraocular pressure (IOP) after Nd: YAG laser posterior capsulotomy and its association with the energy used with raised versus normal intraocular pressure in pseudophakes. Comparative, cross-sectional study. Ophthalmology Department, PNS Shifa Hospital, Karachi, from August 2008 to February 2009. Pseudophakes having poor vision due to posterior capsular opacification (PCO) in an otherwise normal looking eye and intraocular pressure between 10-20 mmHg were included in the study. Patients with diabetic retinopathy, corneal diseases, inflammatory eye diseases, posterior segment surgery, glaucoma, trabeculectomy, maculopathy and any systemic disease were excluded from the study. Particulars of the eligible patients and pre-laser intraocular pressure were entered in specially designed proforma. Nd: YAG laser posterior capsulotomy was done. Laser energy used was noted and then their post-laser intraocular pressure was checked after 4 hours. Unpaired t-test was used for comparison of means of IOP and energy levels. Chi-square test was applied to compare the proportions of patients with raised and the normal IOP with YAG laser energy used during posterior capsulotomy. Raised intraocular pressure (IOP>or=5 mmHg from the baseline) after Nd: YAG laser posterior capsulotomy was noted in both the 'low energy' and the 'high energy' groups but it was more common in the 'high energy' group (p<0.001, r=0.512). Higher YAG laser energy has significantly higher chances of raising IOP. Hence, it was recommended that each patient undergoing Nd: YAG laser capsulotomy should receive minimum possible laser energy and must be followed up for raised intraocular pressure.