Paper
2 March 2015 A wide angle low coherence interferometry based eye length optometer
Alexander Meadway, John Siegwart, Christine F. Wildsoet, Thomas T. Norton, Yuhua Zhang
Author Affiliations +
Abstract
Interest in eye growth regulation has burgeoned with the rise in myopia prevalence world-wide. Eye length and eye shape are fundamental metrics for related research, but current in vivo measurement techniques are generally limited to the optical axis of the eye. We describe a high resolution, time domain low coherence interferometry based optometer for measuring the eye length of small animals over a wide field of view. The system is based upon a Michelson interferometer using a superluminescent diode as a source, including a sample arm and a reference arm. The sample arm is split into two paths by a polarisation beam splitter; one focuses the light on the cornea and the other focuses the light on the retina. This method has a high efficiency of detection for reflections from both surfaces. The reference arm contains a custom high speed linear motor with 25 mm stroke and equipped with a precision displacement encoder. Light reflected from the cornea and the retina is combined with the reference beam to generate low coherence interferograms. Two galvo scanners are employed to steer the light to different angles so that the eye length over a field of view of 20° × 20° can be measured. The system has an axial resolution of 6.8 μm (in air) and the motor provides accurate movement, allowing for precise and repeatable measurement of coherence peak positions. Example scans from a tree shrew are presented.
© (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Alexander Meadway, John Siegwart, Christine F. Wildsoet, Thomas T. Norton, and Yuhua Zhang "A wide angle low coherence interferometry based eye length optometer", Proc. SPIE 9312, Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XIX, 93122J (2 March 2015); https://doi.org/10.1117/12.2082185
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KEYWORDS
Eye

Eye models

Cornea

Signal to noise ratio

Reflection

Retina

Beam splitters

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