Background Accurate biometry is of vital importance in achieving predictable postoperative refraction following cataract surgery. Aim To evaluate the accuracy and consistency in biometry, achieved by the new generation laser biometric system in comparison with the ultrasound biometric system. Methods The study was randomized and prospective. Biometry was performed in 68 eyes of 39 patients by three groups of biometrists (expert, intermediate user, novice). Expert and intermediate users are compared as group A, and expert and novice are compared in group B. Axial length, anterior chamber depth (ACD), and keratometry results are compared by t-test analysis. Results Axial length measurement variation between expert and non experts was 10 times less using laser than ultrasound (Po0.001). ACD measurement variation was also significantly less when using laser compared to ultraound (P ¼ 0.003). Need for some level of user training is indicated in ACD measurement since group A achieved more consistent readings than group B. Keratometry measurements on the laser system were unreliable due to high range of results. Biometric failure was seen in 12% of eyes undergoing laser and 1% undergoing ultrasound biometry. Conclusion Axial length determination by laser biometry is more accurate and consistent at all levels of biometrist expertise, compared to ultrasound biometry. ACD and keratometry measurements on the laser systems need some degree of user training in order to produce consistent results.

Background Disposable devices are increasingly becoming the preferred choice where possible in contact medical equipment. Aim To evaluate the accuracy of the disposable applanation tonometer head as a potential substitute to the standard Goldmann applanation head. Methods The study was prospective. The intraocular pressure recordings in 80 eyes of 42 patients were compared using the disposable and standard Goldmann applanator heads. The Bland and Altman method of assessing agreement between two methods of clinical measurement was used in the analysis. Results The difference in the readings between the two types of tonometer heads was highly variable (mean difference ¼ 0.78 mm Hg, range ¼ À1 to 11 mm Hg). This was because of the distortions on the applanating surface of the disposable device. When the readings associated with the defective heads were excluded, very strong agreement was obtained (mean ¼ 0.07 mm Hg, range ¼ À1 to 2 mm Hg). Conclusion Good agreement with standard Goldmann applanation is achieved with the disposable heads except where surface distortions induce significant errors. Careful inspection to ensure well-structured disposable units is imperative in disposable applanation tonometry.

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