Repeatability and agreement in optical biometry of a new swept-source optical coherence tomography-based biometer versus partial coherence interferometry and optical low-coherence reflectometry.

PURPOSE: To estimate the repeatability of biometric parameters obtained with a new swept-source biometer and to compare the agreement with that of partial coherence interferometry (PCI) and optical low-coherence reflectometry (OLCR). SETTING: Department of Ophthalmology, Helios Hospital Erfurt, Erfurt, Julius-Maximilians University, Würzburg, and Philipps University, Marburg, Germany. DESIGN: Prospective comparative multicenter clinical study. METHODS: Biometry was taken with the use of 3 different biometers: the IOLMaster 700 swept-source biometer, the PCI-based IOLMaster 500, and the OCLR-based Lenstar LS 900. Axial length (AL), anterior chamber depth (ACD), and spherical equivalent (SE) were compared between swept-source and PCI biometry and central corneal thickness (CCT) and lens thickness (LT) between swept-source and OLCR biometry. The repeatability of swept-source biometry was evaluated on the basis of 3 measurements captured for each patient. RESULTS: One hundred twenty cataract eyes were included in the study. The mean difference between swept-source and PCI biometry for AL, ACD, and SE measurements was 4 µm ± 25 (SD), 17 ± 122 µm, and -0.001 ± 0.19 diopter (D), respectively. The mean difference between swept-source and OLCR biometry for LT and CCT measurements was 21 ± 122 µm and 0.15 ± 4.51 µm, respectively. Differences between swept-source biometry and the other devices distributed around zero without statistical significance. The standard deviation of repeatability for AL, ACD, LT, CCT, and SE was 8.8 µm, 9.8 µm, 2.3 µm, 19.5 µm, and 0.1 D, respectively. CONCLUSIONS: Swept-source biometry showed high repeatability performance for all biometric parameters. The agreement of AL, ACD, and SE between swept-source and PCI biometry as well as that of LT and CCT between swept-source and OLCR biometry was excellent. It remains to be validated whether high repeatability shown by swept-source biometry will result in better postoperative refractive outcomes. FINANCIAL DISCLOSURE: Drs. Blum and Sekundo are members of the Scientific Advisory Board of Carl Zeiss Meditec AG. Drs. Peter and Bühren are employees of Carl Zeiss Meditec AG.

Foveal pit morphology evaluation during optical biometry measurements using a full-eye-length swept-source OCT scan biometer prototype.

PURPOSE: To assess the scan quality of foveal pit morphology (FPM) and to quantify central retinal thickness (CRT) during routine optical biometry measurements with a full-eye-length swept-source optical coherence tomography (SS-OCT) scan biometer prototype (IOLMaster700) and to compare these results with standard examinations using spectral-domain optical coherence tomography (SD-OCT) technique (Cirrus4000 SD-OCT). METHODS: As part of a SS-OCT scan protocol to measure biometric parameters for intraocular lens power calculation, central horizontal 1 mm retinal B scans were taken from phakic (group I) and pseudophakic (group II) nonvitrectomized eyes. To evaluate FPM, macular scans of either examination technique were subjectively analyzed and compared. Repeated CRT measurements were performed to analyze repeatability and consistency of IOLMaster700 recordings. These results were compared with CRT evaluations using SD-OCT. RESULTS: Overall, 146 eyes of 146 patients were included in this series. The subjective assessments of FPM are illustrated. Repeated CRT measurements (repeatability) with the IOLMaster700 disclosed an overall intraclass correlation of 0.57 (group I: 0.48; group II: 0.89). Overall coefficient of variation (accuracy) was calculated to be 12.43% (group I: 14.21%; group II: 5.66%). The comparison of CRT measurements between both devices showed significant differences in group I (p = 0.006). CONCLUSIONS: Compared with SD-OCT, resolution of the 1 mm retinal B scan of SS-OCT scan biometry was lower. However, advanced pathologic characteristics were clearly discernible. Repeatability and accuracy of CRT measurements were acceptable though lower than with the standard SD-OCT technique. The CRT differed significantly in eyes of particular interest (group I) between both devices. The new scan could provide useful information for subsequent patient examination and further treatment planning for cataract surgery.

Analysis of optical side-effects of fs-laser therapy in human presbyopic lens simulated with modified contact lenses.

BACKGROUND: In a single-blinded study, optical side-effects of a potential femtosecond (fs)-laser therapy in presbyopic human lenses were tested. Simulation of this therapy was carried out by applying fs-laser patterns into standard contact lenses (CL). METHODS: In the first part of the study, the influence of the numerical aperture on optical side-effects was investigated by comparing a typical fs-LASIK configuration to a fs-presbyopia treatment (n = 11). The second part focused on a possible improvement of visual performance by comparing a regular grid pattern to a randomly chosen spacing of the laser spots (n = 16). Visual acuity was measured with ETDRS charts, contrast sensitivity with F.A.C.T. charts and mesopic vision with Mesotest II. Forward scattered light was measured with the C-Quant (both instruments: Oculus Optikgeräte GmbH, Germany). A questionnaire detected subjective quality of vision. Differences between laser-treated and untreated CL and among the modifications were analyzed. RESULTS: The laser-treated and standard CL indicated no significant difference in visual acuity, contrast sensitivity and mesopic vision without glare. While wearing modified lenses with a regular grid, quality of vision decreased significantly by means of mesopic vision with glare and subjective straylight. These modifications also caused an impairment of subjective quality of vision. In contrast, there was no significant difference between the random pattern and standard CL. CONCLUSION: The increase of optical side-effects was reproducibly dependent on the geometry of the laser-structure. A randomized grid induced the least limitation. The study results are useful for planning possible laser-patterns in fs-laser therapy of the presbyopic lens.