Laser Capsulorrhexis with Thermal Collagen Denaturing
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Solution Overview
Problem
Current methods for capsulorrhexis in cataract surgery face challenges such as errant tears, difficulty in visualizing the capsule, maintaining anterior chamber depth, and handling of weak or elastic capsules, leading to complications like posterior capsule tears and misalignment of intraocular lenses.
Innovation Solution
Laser-assisted ophthalmic surgery using a scanning treatment laser beam with a programmed scan profile to create a closed curve on the anterior lens capsule, causing thermal denaturing of collagen without ablating tissue, along with a visualization laser beam to aid in alignment and tissue separation, ensuring precise and controlled capsulorrhexis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual capsulorrhexis is performed using forceps or needle, then the procedure can be completed with simple equipment, but errant tears and radial rips may occur leading to posterior capsule tears
Solution Approach 1:
The patent replaces the manual mechanical system (forceps or needle) with a laser-based system. The laser creates a closed curve incision through photothermal effects, eliminating the need for mechanical grasping and tearing of the capsule. This substitution eliminates errant tears and radial rips while maintaining procedural simplicity through automated laser scanning patterns.
Solution Approach 2:
The laser system performs preliminary visualization by projecting the intended incision pattern onto the capsule before actual incision. This allows the surgeon to verify proper positioning and sizing of the capsulorrhexis opening before laser activation, preventing misalignment and ensuring the incision is centered and appropriately sized for the IOL.
2Manufacturing precision
If a symmetric circular capsulorrhexis is created centered about the visual axis, then proper alignment for IOL implantation is achieved, but difficulty arises in visualizing the capsule and maintaining anterior chamber depth
Solution Approach 1:
The laser system eliminates the need for manual capsule manipulation and visualization challenges. The automated laser scanning system projects the precise circular pattern directly onto the capsule surface, ensuring perfect centering on the visual axis without requiring manual alignment. The laser maintains anterior chamber depth through controlled energy delivery that prevents excessive heating or capsule contraction during the procedure.
Solution Approach 2:
The system creates an optical copy or projection of the desired capsulorrhexis pattern onto the capsule before incision. This visualization layer serves as a template that guides the laser incision, ensuring perfect geometric accuracy and centering without requiring the surgeon to manually measure or align the capsule.
3Strength
If high laser power is used to create thermal denaturing of collagen, then strong capsule rims and mechanical integrity are achieved, but risk of tissue ablation increases
Solution Approach 1:
The laser system uses periodic or pulsed energy delivery along the scanning path, creating controlled thermal zones that denature collagen without continuous high-power exposure. The scanning motion distributes energy temporally and spatially, allowing heat dissipation between pulses and preventing excessive temperature rise that would cause ablation, while still achieving sufficient collagen denaturation for strong capsule rims.
Solution Approach 2:
The laser system replaces mechanical cutting with controlled photothermal effects. By carefully controlling laser parameters (wavelength, power, scanning speed, spot size), the system achieves selective collagen denaturation at the capsule incision line. The thermal energy is confined to a narrow zone along the scanning path, creating strong capsule rims through controlled shrinkage and welding of collagen fibers without ablating surrounding tissue.
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
The laser-assisted method reduces the risk of tears and misalignment, enhances precision, and promotes stronger capsule rims, improving the mechanical integrity and long-term success of cataract surgery by creating a stable opening for intraocular lens implantation.
Implementation Method 1
a power selected to cause thermal denaturing of collagen in the anterior lens capsule resulting in thermal tissue separation along the closed curve without ablating anterior lens capsule tissue
Implementation Method 2
a wavelength selected to be strongly absorbed at the anterior lens capsule
Data Source
AI summary
Laser assisted cataract surgery methods and devices utilize one or more treatment laser beams to create a shaped opening in the anterior lens capsule of the eye when performing a capsulorrhexis procedure. A light absorbing agent may be applied to the anterior lens capsule to facilitate laser thermal separation of tissue along a treatment beam path on the lens capsule. Relative or absolute reflectance from the eye, and optionally from a surgical contact lens, may be measured to confirm and optionally quantify the presence of the light absorbing agent, before the treatment beam is applied. Such measurements may be used to determine that sufficient light absorbing agent is present in the lens capsule so that transmission of the treatment beam through the capsule will be below a predetermined threshold deemed safe for the retina and other interior portions of the eye, and may also be used to determine that sufficient light absorbing agent is present to result in complete laser thermal separation of the anterior capsule along the treatment beam path. Visualization patterns produced with one or more target laser beams may be projected onto the lens capsule tissue to aid in the capsulorrhexis procedure. In addition or alternatively, virtual visualization patterns may presented on a display integrated with a laser assisted cataract surgery device to aid in the procedure. The visual axis of the eye may be determined, during surgery for example, with a laser beam on which the patient is fixated. The orientation of a toric IOL may be assessed during or after placement by observing the reflection from the back of the eye of a laser beam on which the patient is fixated. The devices disclosed herein may be attached to or integrated with microscopes.