Bi-radial Patient Interface for Ophthalmic Surgery
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Solution Overview
Problem
Existing ophthalmic surgical procedures face challenges due to corneal wrinkling caused by mismatched radii of curvature between patient interfaces and the eye, leading to distorted laser beams and reduced precision in procedures like cataract surgery.
Innovation Solution
A bi-radial patient interface with a contact element featuring a central portion with a smaller radius of curvature and a peripheral portion with a larger radius of curvature, closely matching the natural curvature of the cornea and sclera, reduces wrinkling by accommodating the complex shape of the eye surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a patient interface with a single radius of curvature is used to attach to the eye, then the device can be structurally simple and easy to manufacture, but it causes corneal wrinkling due to mismatch with the complex corneal surface geometry
Solution Approach 1:
The contact element employs different radii of curvature in different regions: a first radius of curvature in the central region matching the corneal curvature, and a second radius of curvature in the peripheral region matching the scleral curvature. This local differentiation allows each region to conform to the specific geometry it contacts, eliminating corneal wrinkling while maintaining manufacturing feasibility through modular design.
Solution Approach 2:
The contact element is divided into distinct central and peripheral portions with different geometric properties. The central portion with the first radius of curvature interfaces with the cornea, while the peripheral portion with the second radius of curvature interfaces with the sclera. This segmentation enables precise matching of each region to its target surface without requiring complex monolithic structures.
2Device complexity
If a patient interface with mismatched radius of curvature is used, then the device design is simpler, but it causes distorted laser beams and reduced surgical precision
Solution Approach 1:
By providing a first radius of curvature (R1) in the central region that closely matches the corneal radius (7.0-8.0mm) and a second radius of curvature (R2) in the peripheral region that matches the scleral radius (10.0-12.0mm), the contact element creates uniform optical coupling across the laser beam path. This eliminates corneal wrinkling that would otherwise distort the laser beam, thereby improving surgical precision without excessive complexity.
3Reliability
If a patient interface applies pressure to immobilize the eye, then the eye can be held steady for surgery, but it causes corneal deformation and wrinkling
Solution Approach 1:
The contact element applies immobilization pressure through a central region with radius R1 that matches the corneal curvature, allowing stable contact without deformation. The peripheral region with radius R2 matches the scleral curvature, providing additional stabilization. This localized geometric matching enables effective eye immobilization while distributing pressure to prevent corneal wrinkling.
Solution Approach 2:
The contact element is pre-formed with specific radii of curvature (R1 and R2) that match the natural curvatures of the cornea and sclera before contact. This preliminary geometric configuration ensures that when the patient interface is applied to immobilize the eye, the cornea maintains its natural shape without deformation, as the contact surfaces are already adapted to the eye's geometry.
Data Source
AI summary
To improve the precision of ophthalmic surgical procedures by reducing corneal wrinkling, a patient interface for an ophthalmic system can include an attachment portion, configured to attach the patient interface to a distal end of the ophthalmic system; a contact portion, configured to dock the patient interface to an eye; and a contact element, coupled to the contact portion, configured to contact a surface of a cornea of the eye as part of the docking of the patient interface to the eye, and having a central portion with a central radius of curvature Rc and a peripheral portion with a peripheral radius of curvature Rp, wherein Rc is smaller than Rp.