Aplating Device with Liquid Interface for Refractive Surgery
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Solution Overview
Problem
Refractive surgical procedures using lasers face challenges in precise positioning of the laser focus due to the curvature of the eye's surface, which is exacerbated by mechanical stress and unpredictability when flattening the eye for accurate cuts.
Innovation Solution
A device with a transparent glass plate and an elastic foot area that forms a receiving space with a liquid of matching refractive index, allowing the laser beam to pass through with minimal refraction, and is held in place by negative pressure, enabling precise positioning and reduced mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a glass plate is pressed onto the corneal surface to flatten it, then the laser focus positioning is improved, but mechanical stress on the eye increases and comfort deteriorates
Solution Approach 1:
A liquid medium with refractive index matching the cornea is introduced between the corneal surface and the aplanating plate. This liquid intermediary reduces the mechanical stress transmitted to the eye while maintaining the optical correction function, as the refractive index matching minimizes additional refraction at the liquid-cornea interface.
Solution Approach 2:
The refractive index of the liquid medium is specifically selected to match that of the corneal tissue. This parameter change allows the liquid to optically blend with the cornea, reducing refraction at the interface and enabling effective aplanation with reduced mechanical stress.
2Stability of the object's composition
If the corneal surface is flattened by pressing, then the phase front deformation is reduced, but the mechanical properties become unpredictable
Solution Approach 1:
The liquid medium acts as a compliant intermediary layer between the rigid aplanating plate and the soft corneal tissue. This intermediary allows for controlled, uniform deformation of the cornea while distributing mechanical stress evenly, making the mechanical properties more predictable during the procedure.
3Measurement precision
If a rigid structure is used to maintain device stability, then positioning accuracy is improved, but adaptability to the curved eye surface deteriorates
Solution Approach 1:
The aplanating plate is designed with a flexible or adjustable mechanism that allows it to adapt to the curved corneal surface while maintaining a stable reference frame for positioning. The flexible nature enables conformal contact with the eye surface, improving both adaptability and positioning accuracy.
Solution Approach 2:
The device incorporates adjustable components that allow dynamic adaptation to different eye geometries. The aplanating plate can be positioned and adjusted during the procedure to optimize contact with the corneal surface, combining stability with adaptability.
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
Enables precise and accurate focusing of the laser beam at specific depths within the eye, enhancing the precision and comfort of refractive surgical interventions.
Implementation Method 1
When the device is placed on the eye and the receiving space is filled with a liquid that has a refractive index that is in the range of the refractive index of the eye or the glass plate - which is the case, for example, for water or saline solution - the refraction of the laser light is determined by the surface of the transparent plate and no longer by the corneal surface.
Implementation Method 2
The device is held to the cornea by negative pressure. This negative pressure can be formed by suction with a suitable device.
Data Source
AI summary
In refractive surgery, a laser beam strikes the curved surface (14) of the cornea of the eye (12). The curvature of the surface causes the laser beam to refract and the laser beam front to deform, making it difficult to precisely position the laser beam at a specific depth within the eye (12). This problem is eliminated by a device (10) according to the invention. The device (10) comprises a base body (16) that carries a plate (22) transparent for at least a predetermined wavelength range and has an elastic base (34, 36). When the device is placed on the corneal surface (14) of an eye (12), a receiving chamber (26) for a liquid is formed. Liquid is introduced into the receiving chamber (26) via an inlet (36).The laser beam is then guided through the liquid via the transparent plate to the corneal surface (14), so that the outward-facing surface of the transparent plate (22) determines the refractive properties. If this surface (52) is flat, the phase front of the laser beam is hardly shifted, thus enabling, as desired, improved focusing of the laser beam at a specific depth in the eye (12).