Laser Capsulorrhexis with Dye Absorption for Tear Prevention
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Solution Overview
Problem
Current methods for capsulorrhexis in cataract surgery face challenges such as errant tears, difficulty in visualizing and grasping the capsule, maintaining anterior chamber depth, and issues with older patients or young children due to mechanical limitations, leading to complications like posterior capsule tears and IOL misalignment.
Innovation Solution
A laser-assisted ophthalmic surgery method using a pulsed treatment laser with a two-dimensional scanner to create a closed curve opening in the anterior lens capsule, employing a biocompatible dye to absorb the laser energy and induce thermal denaturing or ablation, thereby forming a stable capsulorrhexis with reduced risk of tears and enhanced mechanical integrity.
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 posterior capsule tears occur leading to complications
Solution Approach 1:
The patent replaces the manual mechanical technique of capsulorrhexis (using forceps or needle to tear the capsule) with a laser-based system. The laser creates a continuous circular incision through photothermal ablation, eliminating the need for mechanical grasping and tearing. This substitution eliminates errant tears associated with manual manipulation while maintaining procedural simplicity through automated laser scanning.
Solution Approach 2:
The patent introduces a biocompatible dye (such as trypan blue or indocyanine green) as an intermediary substance that enhances laser absorption by the lens capsule. The dye is applied to the capsule surface before laser treatment, allowing for precise and controlled incision creation. This intermediary enables the laser to create a clean, continuous circular opening without mechanical contact, thereby preventing errant tears while maintaining procedural feasibility.
2Ease of operation
If manual capsulorrhexis is performed, then the surgeon can adapt to different patient conditions, but visualization and grasping of the capsule become difficult leading to operational challenges
Solution Approach 1:
The biocompatible dye serves as a visualization intermediary that stains the lens capsule, making it clearly visible under the surgical microscope. This enhanced visualization allows the surgeon to precisely monitor the laser incision process without needing to mechanically grasp the capsule. The dye-stained capsule provides continuous visual feedback, improving ease of operation while eliminating the need for secure grasping.
Solution Approach 2:
The laser system replaces the need for mechanical grasping of the capsule entirely. The automated laser scanning system creates the incision based on pre-programmed parameters that can be adapted to different patient conditions (capsule thickness, elasticity, pupil size). This eliminates operational challenges related to grasping security while maintaining adaptability through programmable laser parameters.
3Adaptability or versatility
If mechanical capsulorrhexis is performed on older patients or young children, then the procedure can be attempted, but weak zonules and soft elastic capsules make mechanical rupture extremely difficult
Solution Approach 1:
The laser system replaces mechanical rupture techniques with photothermal ablation. The laser energy directly vaporizes or coagulates the capsule tissue along a predetermined circular path, creating a clean opening without requiring mechanical tearing. This approach works effectively on capsules with varying elasticity and strength, including the soft, elastic capsules of older patients and young children, thereby improving adaptability while maintaining ease of operation.
Solution Approach 2:
The laser parameters (power, pulse duration, scanning speed) can be adjusted to match the specific characteristics of different patient populations. For soft, elastic capsules in older patients or children, lower power and slower scanning speeds can be used to ensure complete incision without causing excessive thermal damage. This parameter adaptability enables successful capsulorrhexis across diverse patient conditions that would be difficult with mechanical techniques.
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 improves the precision and stability of capsulorrhexis, reducing complications like errant tears and misalignment, while allowing for better visualization and tissue separation, leading to improved long-term success in cataract surgery by creating a more elastic and resistant capsular rim.
Implementation Method 1
The treatment laser beam has a wavelength absorbed by a biocompatible dye
Implementation Method 2
Absorption of the treatment laser beam pulses by the biocompatible dye at the anterior lens capsule causes thermal denaturing of collagen in the anterior lens capsule resulting in thermal tissue separation along the closed curve
Implementation Method 3
Tissue separation along the closed curve to form the opening may alternatively, or additionally, result from other mechanisms (e.g., ablation of anterior lens capsule tissue) mediated by absorption of the treatment laser beam pulses by the biocompatible dye
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.