I.O.L. Master 700 Optical Biometry versus Conventional Ultrasound Biometry (Immersion Technique) in Intra Ocular Lens Power Calculation in High Myopia Patients

Author(s): Rinki Saha1 , Angana Sinharay2 , Jayanta Kuila3 , Purban Ganguly4

BACKGROUND IOL implantation has turned into a very significant part of modern-day cataract surgery. IOL implantation no longer only sub serves the purpose of better visual rehabilitation but is currently considered as a form of refractive surgery. Accurately predicted post-operative visual outcome has become the necessity of present times. In this regard, precise pre-operative biometric measurement is an essential pre-requisite. The aim of the study was to compare the accuracy of optical biometry and conventional ultrasound measurement of the preoperative intraocular lens power calculation formula (SRK/T) of highly myopic eye. METHODS This study included 58 eyes of 50 patients [(10 cases of bilateral and 48 cases of unilateral cataract) (20 female (45%) and 30 male (55%)] with extreme myopia and axial lengths ≥25.0 mm with cataract as the only ocular pathology. Patients were divided in two groups. Group 1 (the optical biometry group) included 25 patients and group 2 (the A-scan ultrasound group) included 25 patients. Those eyes were included in the present study which had visually significant lenticular opacity. Eyes which were not suitable for phacoemulsification and primary in-thebag posterior chamber IOL insertion were excluded for minimizing the confounding factors, all patients were operated by the same surgeon and implantation of single piece soft hydrophobic aspheric acrylic IOL from the same manufacturer was done. (power range ±12.0. D to ±16.0 D). RESULTS This study was carried out on 58 Eyes of 50 high myopia patients who had initially presented with visually significant cataract. Patients were randomly divided into two groups: First Group (Group 1 included 30 eyes all of which underwent Optical Biometry using a single machine from the same manufacturer (Zeiss 700 IOL master) and Second Group (Group 2) included 28 eyes all of which underwent conventional A Scan Ultrasound Biometry using a single machine from the same manufacturer (Sonomed PAC SCAN 300 AP). The proportion of eyes with postoperative spherical equivalent of ≤±0.5 D, ≤±0.75 D and ≤±1 D in the conventional ultrasound biometry group were significantly lower when compared with corresponding proportions in the IOL Master group (p<0.00) respectively. CONCLUSIONS Optical Biometry using partial coherence interferometry gives significantly better pre-operative IOL power prediction as compared to conventional ultrasound-based biometry in high myopia patients.