Abstract
Purpose :
The Brillouin Optical Scanning System (BOSSTM) uses scattering of laser light to measure miniscule changes in the wavelength (frequency shift) of light reflected back from the cornea or crystalline lens. The measured frequency shift directly correlates with the tissue’s elastic property (i.e., stiffness). In this study, BOSS measurements from patients, in vivo, and porcine eyes, ex vivo, were performed to investigate the repeatability and reproducibility of the BOSS device.
Methods :
Thirty-three adults were tested at a clinical site, with 3 BOSS devices that were all operated by different personnel. Following a standard ophthalmic exam, 3 single-point axial lens scans were performed on the human participants on each of the devices. On a second visit, each subject underwent 3 cornea scans, using a 7-point corneal pattern. For the ex vivo portion of the study, 5 old and 5 young porcine eyes were mounted on a custom setup. In the lens experiment, 3 replicate scans were performed per lens. Three cornea exams were also performed on each porcine eye with the 7-point pattern. The coefficient of variation (95% CV) was calculated within and between eyes, and within devices.
Results :
No adverse effects occurred during the clinical trial. Lens measurements from 31 subjects (31 eyes) showed an average maximal stiffness of 3.33 GPa, with CV values from 1.1% to 2.1% across devices, and reproducibility CV of 2.1%. The average stiffness from cornea scans from 32 subjects (32 eyes) was 2.83 GPa; the CV values ranged from 0.5% to 1.4% for the 3 devices, and the reproducibility CV was 1.6%. The “old” porcine eyes were from animals over 4 months old versus the 8-week-old (“young”) eyes. The average maximal stiffness and CV values for the porcine eyes were 3.91 GPa and 1.0%, respectively, for the lenses from the old porcine eyes and 3.71 GPa and 1.1% from the young-eye lenses. For the cornea measurements, the CV values averaged 1.2% and 1.8% for the old and young eyes respectively, and the stiffness values averaged 2.73 and 2.78 GPa, respectively.
Conclusions :
The BOSS was shown to be safe and effective for measuring the longitudinal elastic modulus of the cornea and crystalline lens. Based on the measurement repeatability and reproducibility demonstrated in these tests, the BOSS has utility in measuring the stiffness of the anterior-segment tissues of the eye under in vivo and ex vivo conditions.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.