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Background: The OA-1000 (Tomey, Japan) is a new optical biometer, which allows measurements of axial length (AL), anterior chamber depth (ACD) and corneal thickness (CT) due to partial coherence interferometry (PCI) technology. The aim of this study was to compare the OA-1000 results with those obtained with the IOLMaster and contact applanation A-scan ultrasonography., Methods: We examined 133 eyes of 75 patients with age related cataract. Mean age was 72.0 ± 9.5 years. Biometry measurements of AL and ACD were performed with the Tomey OA-1000 based on PCI, the IOLMaster based on PCI (AL) and slit projection (ACD), and the Tomey AL-3000 based on contact applanation A-scan ultrasonography., Results: Mean AL using the IOLMaster was 23.21 ± 1.08 mm, using the AL-3000 was 22.79 ± 1.04 mm, using the OA-1000 it was 22.97 ± 1.1 mm. Mean ACD using the IOLMaster was 2.99 ± 0.41 mm, using the OA-1000 3.40 ± 0.46 mm, using the Tomey AL-3000 it was 2.93 ± 0.43 mm. Mean difference between the AL and ACD measured with the OA-1000 and the IOLMaster was 0.22 ± 0.047 mm and 0.40 ± 0.33 mm, between OA-1000 and the AL-3000 it was 0.19 ± 0.23 mm and 0.47 ± 0.33 mm, and between IOLMaster and AL-3000 it was 0.42 ± 0.23 and 0.09 ± 0.36 mm. For AL the correlation coefficient R between IOLMaster and OA-1000 was 0.999, between IOLMaster and AL-3000 it was 0.976, between AL-3000 and OA-1000 it was 0.977. For ACD R between IOLMaster and OA-1000 was 0.735, between IOLMaster and AL-3000 it was 0.822, between AL-3000 and OA-1000 it was 0.716 (all p < 0.001)., Conclusions: Compared with other used clinical instruments the OA-1000 generates accurate results. Although differences were found, the OA-1000 provided results that correlated well with the values of IOLMaster and AL-3000.

Purpose: To evaluate the repeatability of corneal hysteresis (CH) and corneal resistance measurements as well as the consistency of the four shots within each measurement using the ocular response analyzer (ORA, Reichert Ophthalmic Instruments, Depew, NY) and to generate a pool of data of a normal population., Methods: A total of 45 eyes from 45 healthy volunteers without ocular pathologies and normal visual acuity were enrolled in this study. A sequence of five consecutive measurements was performed with each patient with the ORA. The biomechanical properties of the cornea in terms of CH and corneal resistance factor (CRF) were recorded, as well as the Goldmann-correlated IOP (IOPg) and cornea correlated IOP (IOPcc). The trend in each measurement sequence was analyzed and Cronbach's α was derived for the repeatability. The average of four shots within each measurement was compared with the best signal value (BSV) provided by the internal data processing of the ORA., Results: Mean value for CH was 11.58 and BSV was 11.55. For CRF, mean value was 11.21 and BSV was 11.28. No significant difference was found between the average value and the BSV of one measurement (p > 0.05). No significant difference was found between the average value and the BSV of the five consecutive measurements, only IOPg showed a significant difference (p = 0.017), average value of IOPg is higher than BSV. Within a sequence of five measurements for each individual, the average values of the four shots per measurement for IOPg and IOPcc are decreasing by 1.19 and 1.05 mmHg on average. The repeatability test revealed good results for CH and CRF (all α are higher than 0.9)., Conclusion: The ORA provides, beside intraocular pressure additional, information about the biomechanical properties of the cornea such as hysteresis and resistance. It proves to yield good repeatability for corneal hysteresis and resistance in normal subjects.