Long-range frequency-domain optical delay line based on a spinning tilted mirror for low-cost ocular biometry

Area of Science:

• Ophthalmic instrumentation
• Biomedical optics
• Medical device engineering

Background:

• Optical biometry is crucial for ophthalmic applications like cataract surgery planning and myopia monitoring.
• High cost and limited portability of current devices restrict access, particularly in low-resource settings.

Purpose of the Study:

• To develop a novel, low-cost frequency-domain optical delay line (FD-ODL) for improved accessibility of optical biometry.
• To integrate this FD-ODL into a compact time-domain (TD)-biometer suitable for diverse settings.

Main Methods:

• Designed a novel FD-ODL using an inexpensive stepper motor and a spinning tilted mirror to decouple axial scan range and A-scan rate.
• Characterized scanning performance for different mirror tilt angles.
• Integrated a prototype low-cost FD-ODL into an optical low-coherence reflectometry (OLCR) setup.

Main Results:

• Achieved an axial scan range of 6.61 mm and an A-scan rate of 10 Hz with a 1.5-degree tilt angle.
• Experimental measurements of intraocular distances in a model eye showed good agreement with a custom swept-source optical coherence tomography (SS-OCT) system and commercial biometers.

Conclusions:

• The novel low-cost FD-ODL design successfully enables accurate intraocular distance measurements.
• This technology has the potential to significantly increase patient access to essential ophthalmic diagnostic tools in underserved regions.