Ophthalmic ranging instrument

JP2025148261A5Pending Publication Date: 2025-12-22OPTOS PLC
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Patent Information

Application Number
JP2025032844
Authority / Receiving Office
JP · JP
Patent Type
Applications
Current Assignee / Owner
Priority Date
2024-03-25
Filing Date
2025-03-03
Publication Date
2025-12-22

AI Technical Summary

Technical Problem

Conventional stereo distance measuring devices struggle with accurate distance measurement when the eye is out of focus or within a narrow range due to specular highlights obscuring pupil centers, leading to unreliable distance determination.

Method used

An ophthalmic device uses specular highlights from the eye's cornea to measure distance by varying spatial distribution, processed by a processor to determine distance indicators, adjusting the device's position to ensure accurate measurement within a predetermined range.

Benefits of technology

The method provides reliable distance measurement resilient to image blur and reduces hardware complexity by using specular highlights, complementing conventional stereoscopic techniques for precise alignment.

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Abstract

To provide a reliable ophthalmic ranging instrument.SOLUTION: An ophthalmic apparatus arranged to determine an indication of a distance between the ophthalmic apparatus and an eye of a subject comprises: an illumination device operable to illuminate the eye; an imaging device to acquire an image of the eye; where the illumination device and the imaging device are arranged such that the image of the eye comprises a specular highlight from the illumination device having a spatial distribution in the image which varies with the distance between the ophthalmic apparatus and the eye; and a processor. The processor is arranged to: process the image to determine a value of an indicator which is indicative of a property of the spatial distribution; and use the determined value of the indicator and a mapping which maps values of the indicator to corresponding values of the distance between the ophthalmic apparatus and the eye, so as to determine the distance between the ophthalmic apparatus and the eye.SELECTED DRAWING: Figure 2
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