Ophthalmological Laser System for Corneal Shape Measurement
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Solution Overview
Problem
Current ophthalmological laser systems face challenges in accurately determining the shape of the cornea during keratoplasty, leading to inaccuracies in refractive correction and transplant placement, and the formation of optically opaque bubbles during femtosecond laser incisions, which complicates tissue detachment and prolongs surgery.
Innovation Solution
An ophthalmological laser system with a detection beam path and confocal aperture diaphragm to map detection light from the cornea, allowing for three-dimensional scanning and precise measurement of the posterior boundary layer, which serves as a reference for keratoplastic incisions, and an immobilization device to maintain the cornea's shape during measurement and treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the cornea is measured outside of actual surgery using contactless methods (Scheimpflug camera, OCT), then the measurement process is non-invasive, but the corneal shape parameters become inaccurate due to applanation during surgery
Solution Approach 1:
The system performs preliminary measurement of the posterior boundary layer using confocal scanning before the laser treatment. This allows the corneal shape to be captured in its natural state without applanation, providing accurate parameters for subsequent keratoplasty while avoiding the need for contactless measurements that may not reflect the actual surgical condition
Solution Approach 2:
The confocal scanning system acts as an intermediary between the laser treatment and the corneal measurement. It provides a reference system that can measure the posterior boundary layer with high precision without requiring contactless measurement methods, thus eliminating the applanation problem while maintaining measurement accuracy during surgery
2Device complexity
If femtosecond laser incisions are made for lamellar keratoplasty, then only one laser system is required, but optically opaque bubbles form during the procedure
Solution Approach 1:
The confocal scanning system provides real-time feedback about the corneal structure and bubble formation during the laser procedure. This allows the system to detect and monitor opaque bubble formation, enabling adjustments to treatment parameters or intervention to eliminate bubbles that would otherwise complicate tissue detachment
Solution Approach 2:
The system replaces mechanical bubble removal methods with optical detection and monitoring through confocal scanning. Instead of relying on mechanical intervention to address bubble formation, the system uses optical fields to detect, monitor, and provide feedback for managing bubble formation throughout the procedure
3Stability of the object's composition
If the cornea is held on the laser through contact glass and suctioning, then the cornea is immobilized for treatment, but the corneal shape is altered (applanation)
Solution Approach 1:
The system performs the confocal measurement of the posterior boundary layer before the cornea is applanated by contact glass and suctioning. This preliminary action captures the corneal shape in its natural state, allowing accurate measurement without the distorting effects of immobilization, while still enabling stable treatment during surgery
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 enables highly accurate determination and treatment of the cornea's shape during surgery, reducing treatment risks and improving the chances of successful refractive correction by allowing precise placement of incisions and minimizing the formation of opaque bubbles.
Implementation Method 1
a detection beam path with a confocal aperture diaphragm and a detector for mapping of detection light from the focused part of the examination region
Implementation Method 2
which scans the cornea three-dimensionally through irradiating said cornea at illumination laser power by means of the scanner unit at several spots
Implementation Method 3
a photodisruption is produced in the focus, which leads to a minimal formation of bubbles in the stromal tissue
Implementation Method 4
The ablation of the stromal tissue, necessary for a refractive correction, is subsequently executed conservatively by means of an excimer laser
Implementation Method 5
the cornea is held on the femtosecond laser through the application of a contact glass and suctioning of the eye
Implementation Method 6
suctioning of the eye, whereby, as a rule, the shape of the cornea is altered (applanation)
Data Source
AI summary
An ophthalmological laser system and operating method wherein laser-supported operative interventions can be achieved with higher accuracy. The cornea is irradiated with an ophthalmological laser and a detection light confocally recorded, the cornea being scanned in three-dimensions by irradiation with an illuminating laser power using a scanner unit along several directions at several points. Using the simultaneously recorded detection light the position and/or shape of a posterior boundary surface of the cornea is determined. A lamella parallel to the posterior boundary surface can then be cut.