ABSTRAK Rawatan konvensional laser argon menyebabkan ketebalan sementara pada lapisan saraf retina (RNFL). Tetapi kesan dari 'pattern scanning laser' (PASCAL) tidak banyak diketahui. Kajian ini dilakukan untuk membandingkan kesan selepas konvensional laser argon dibandingkan dengan & Health 2016;11(2): 199-208 Maimunah M. et al. The principle by which the laser exerts its therapeutic effects relies on the destruction of the outer retina. This reduces the oxygen demand while maintaining a constant oxygen input. Laser burns may also serve as physiological windows through which oxygen diffuses from the choroid, increasing vitreous oxygenation and induced vasoconstriction (VelezMontota et al. 2010). However, despite the efficacy for preventing severe visual loss, laser PRP is often associated with substantial ocular side effects, such as ABSTRACT Conventional argon laser causes transient thickening of retinal nerve fibre layer (RNFL). The effect of pattern scanning laser (PASCAL) has not been well described. We compared the immediate changes in peripapillary RNFL thickness post-panretinal photocoagulation between conventional argon lasers and PASCAL in patients with diabetic retinopathy changes. A total of 32 subjects were recruited. There were 16 patients in the argon group and 16 patients in PASCAL group. Diabetic patients were recruited from Ophthalmology Clinic, Universiti Kebangsaan Malaysia Medical Centre (UKMMC). Complete eye examinations and fundus photographs were performed at baseline prior to laser treatment, and post-laser treatment at two and four months. RNFL thickness was measured using time domain optical coherence tomography. Both groups were comparable with respect to clinical characteristics and demographics. There was no significant difference in average RNFL thickness between the two groups prior to treatment (p= 0.323). RNFL post-laser treatment for patients receiving conventional argon laser remained unchanged with no significant differences in all quadrants at any time-point (two and four months). However, for the PASCAL group, significant thickening occurred at four months for average RNFL and the inferior quadrant (p <0.05). The other quadrants similarly demonstrated increasing thickness at four months but this did not reach statistical significance. Transient RNFL thickening occurs in both conventional and PASCAL laser patients. The PASCAL laser induces a greater increase in RNFL thickness than the argon laser group. Important events, such as laser eye treatments and even type of laser used, are worthy of consideration when evaluating RNFL.