Alignment Light Generator for Ophthalmic Examination
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Solution Overview
Problem
Current ophthalmic instruments face challenges in accurately aligning with the eye, particularly for examinations that require optical access behind the iris, leading to issues like dim or vignetted images and spurious reflections due to eye movements and lack of precise alignment verification.
Innovation Solution
The ophthalmic examination apparatus employs an alignment light generator that directs beams towards the cornea, using reflected beams to determine the correct alignment through sensors, providing guidance for the user or operator to adjust the alignment, and potentially utilizing automated mechanisms for precise spatial and rotational alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional ophthalmic instruments are used without alignment assistance, then the device complexity is low, but the alignment precision is poor leading to dim and vignetted images
Solution Approach 1:
The alignment light generator projects alignment lights onto the cornea before the actual examination, allowing the operator to adjust the instrument position in advance. This preliminary alignment action ensures the optical axis is correctly positioned before imaging begins, solving the alignment precision problem without requiring complex real-time adjustment mechanisms during examination.
Solution Approach 2:
Alignment lights serve as an intermediary visual indicator between the instrument's optical axis and the patient's eye. These visible light projections mediate the alignment process by providing a clear visual reference that the operator can use to adjust positioning, thereby improving alignment precision without adding complex sensor systems or automated mechanisms.
2Productivity
If manual alignment adjustment is used, then the device complexity is low, but the alignment time is long and productivity is reduced
Solution Approach 1:
The alignment light generator provides immediate visual feedback to the operator about the current alignment status. When the optical axis is correctly positioned, the alignment lights appear at specific locations on the cornea that indicate proper alignment. This real-time feedback mechanism enables rapid iterative adjustment, significantly reducing alignment time without requiring automated positioning systems.
3Reliability
If the optical axis is not precisely aligned with the eye, then the instrument structure can be simpler, but the image quality deteriorates with spurious reflections and vignetting
Solution Approach 1:
By projecting alignment lights onto the cornea before examination, the system enables preliminary verification of optical axis alignment. This allows the operator to ensure correct positioning before capturing images, preventing spurious reflections and vignetting without requiring complex real-time image correction algorithms or multiple camera systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves alignment accuracy, reduces alignment time, and enhances the usability of ophthalmic instruments, especially for instruments like fundus cameras, by ensuring proper eye alignment, resulting in clearer and more reliable images.
Implementation Method 1
employing an alignment light generator to direct beams of light towards the cornea, utilising reflections to indicate correct alignment
Data Source
AI summary
An ophthalmic examination apparatus comprises an alignment light generator, which directs beams of light from separate locations toward an image of an aperture stop of an imaging unit of the ophthalmic examination apparatus, and causes an envelope of the beams of light to converge to and diverge from a waist, which is within an alignment range of the ophthalmic examination apparatus. An eye is at an examination location with respect to the imaging unit when the waist of the envelope is located at least partly inside a pupil of the eye. The examination location of the ophthalmic examination apparatus is within the alignment range. The imaging unit receives reflections of the beams of light from a cornea of the eye within the alignment range, the eye being similar to a standard eye within standard tolerances. A user interface of the ophthalmic examination apparatus presents guidance information on a location of the eye with respect to the examination location based on locations of the reflections of the beams of light on a detecting surface of the imaging unit.