New non‐contact biometer

Abstract

Purpose To evaluate and compare axial length (AL), anterior chamber depth (ACD), lens thickness (LT), and central corneal thickness (CCT) measurements assessed by optical biometry (OB), ultrasound biometry (UB), optical low coherence reflectometry pachymetry (OLCR‐P), and by a new prototype applying optical low coherence reflectometry biometry (OLCR‐B). Methods OLCR‐B (Haag‐Streit), OLCR‐P (optical low coherence reflectometry pachymetry; Haag‐Streit), OB (IOLMaster, Zeiss), and UB (Tomey AL‐3000) were performed in 35 eyes of 20 patients with incipient cataract. Among the patients were 13 women (age 60‐88) and 7 men (age 53‐90). There were no exclusion criteria. Bland‐Altman analysis was performed to investigate agreement of AL, ACD, LT and CCT measurements between the devices. Correlation between the techniques was also determined using linear regression. All measurements were performed according to the manufacturers recommendations. Results The mean AL was for OLCR‐B 24.35 mm ± 2.32 (SD), OB 24.33 mm ± 2.41, and UB 24.03 mm ± 2.27; the mean ACD for OLCR‐B 3.10 mm ± 0.51, OB 3.15 mm ± 0.52, and UB 3.09 mm ± 0.47; the mean LT for OLCR‐B 4.71 mm ± 0.42, and UB 4.73 mm ± 0.49; the mean CCT for OLCR‐B 543 mm ± 44, OLCR‐P 536 mm ± 32, and UB 541 mm ± 41. Bland‐Altman analysis and linear regression showed high correlation between the devices. Conclusion OLCR‐B, OLCR‐P, OB and UB give comparable results in patients with incipient cataract. The advantages of the OLCR‐B prototype are the non contact method, the exact measurement of AL, ACD, LT and CCT on the same interferometry method and hence the short duration of the measurements. Commercial interest