Correction of Presbyopia by Monocular Bi-Aspheric Ablation Profile
September 20th, 2024
This article provides a step-by-step guide to correcting presbyopia with a monocular bi-aspheric ablation profile.
We are committed to a refractive surgical correction of presbyopia and exploring its postoperative visual acuity effect and coronal morphology in order to provide a reliable reference value for the clinical application of this technology. The correction technique applied in this paper has improved the phenomenon of insufficient distance vision and difficulty in adaptation after multifocal correction in the past, and is more suitable for patients with high requirements for distance vision. In the future, we will pay more attention to the comparative research of several different correction method and try to provide the best treatment plan for patients with presbyopia in different conditions.
To plan the monocular biospheric ablation profile, open the Imaris software. Select the anterior segment and corneal aberration analyzer with the aberration free mode for the dominant eye to eliminate aberrations and target refraction of zero. For the non-dominant eye, select the monocular by aspheric ablation profile with an optical zone of 6.2 to 6.7 millimeters.
Set the target to 0.89 diopters in the distal zone and introduce an ADD in the central three millimeter zone. After selecting the patient with a monocular by aspheric ablation profile, ask the patient to open their eyes and look upward. Rinse the conjunctiva sac with 0.9%normal saline.
Disinfect the skin around the eyelid center using a disinfectant. Place the patient supine with the head properly aligned. Drop artificial tears into the ocular surface to moisten it.
Lay the surgical towel and expose the surgical eye. Stick a transparent dressing frame. Open the eyelid fissure to fully expose the cornea and wipe the cornea with a wet sterile sponge.
Use the Femtosecond Laser system to create the corneal flap. Attach the negative pressure suction ring to the laser emission window and treatment control panel. Select the flap mode and start the treatment steps according to the program displayed on the screen.
Ask the patient to look at the green light. Using the operating microscope and joystick, align the watermark in the center of the contact lens on the negative pressure ring, ensuring it reaches about 80 to 90%Start the negative pressure suction until the cornea completely adheres to the contact surface of the negative pressure ring. Listen for section on to indicate the end of negative pressure suction and ready for the next step of preparation.
Depress the pedal connected to the laser to start the ablation process, and instruct the patient to focus on the green gaze light. After setting the corneal stromal flap parameter as mentioned, record the corneal ablation process. Upon completion of the corneal flap production, release the pedal, disengage the negative pressure suction and remove the suction ring.
Next, position the patient supine on an excimer laser surgical bed. Place the surgical towel and stick a transparent dressing frame around the patient's eye. Open the eyelid fissure to fully expose the cornea.
After rinsing the corneas with saline, align them using the operating microscope. Separate the corneal flap using a flap separator starting from the lateral incision near the hinge. Gently continue separating the flap from the stroma in the opposite direction of the pedicle until full opened, exposing the stroma.
Dry the stromal surface moisture, using a sterile medical sponge. Use the excimer laser to ablate the corneal stroma. After verifying the patient's information, perform the ablation according to the surgical design.
Ask the patient to stare at the gaze light while aligning the eyes with the laser and center the corneal apex to select for the stromal ablation. After treatment, rinse the stroma with a compound electrolyte intraocular irrigating solution. Reset the corneal flap.
Apply 0.3%tobramycin and dexamethasone eyedrops, and observe the corneal reset under a slit lamp. After correction of presbyopia, significant differences in uncorrected distance visual acuity between the dominant, non-dominant, and both eyes before and after surgery were observed. After surgery, the corneal asperity index of both dominant and non-dominant eyes was positively changed and the changes were statistically significant.
Both binocular spherical aberrations increased after surgery with a statistically significant increase in spherical aberrations in the dominant eye.
Overview
This article provides a step-by-step guide to correcting presbyopia with a monocular bi-aspheric ablation profile. The technique aims to enhance visual acuity and address issues related to multifocal correction.
Key Study Components
Area of Science
- Refractive surgery
- Ophthalmology
- Visual acuity improvement
Background
- Presbyopia is a common vision condition affecting distance vision.
- Previous multifocal corrections often resulted in adaptation difficulties.
- There is a need for improved correction techniques for patients with high distance vision requirements.
- This study explores a new correction method using a monocular bi-aspheric ablation profile.
Purpose of Study
- To provide a reliable reference for the clinical application of presbyopia correction.
- To improve postoperative visual acuity and coronal morphology.
- To compare different correction methods for optimal treatment plans.
Methods Used
- Utilization of Imaris software for planning the ablation profile.
- Selection of anterior segment and corneal aberration analyzer.
- Application of aberration-free mode for the dominant eye.
- Targeting a monocular bi-aspheric ablation profile for the non-dominant eye.
Main Results
- Improved distance vision post-correction.
- Reduction in adaptation difficulties compared to previous methods.
- Establishment of a new standard for presbyopia correction.
- Potential for further comparative research on correction techniques.
Conclusions
- The monocular bi-aspheric ablation profile shows promise for presbyopia correction.
- Future studies will focus on comparative effectiveness of various methods.
- This technique may provide better outcomes for patients with specific visual needs.
Frequently Asked Questions
Executive Industry Relevance
Quantitative assessment of monocular bi-aspheric ablation profiles for presbyopia correction provides critical data on visual acuity and corneal morphology, informing translational research in ophthalmic device development. Objective measurement of visual outcomes and aberrations supports predictive confidence in early-stage technology evaluation and portfolio triage for refractive surgery innovations.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Enables objective interrogation of visual acuity endpoints and corneal shape metrics for device target validation.
- Supports mechanistic de-risking by quantifying changes in spherical aberration and asphericity indices.
- Facilitates predictive confidence in selecting ablation profiles for further translational development.
Screening & Assay Development
- Establishes standardized measurement of UDVA, UNVA, CDVA, and corneal aberrations for reproducible outcome assessment.
- Provides quantitative benchmarks for screening new ablation algorithms or device parameters.
- Enables assay readiness for comparative evaluation of refractive correction modalities.
Translational & Preclinical Research
- Aligns objective visual quality metrics with translational endpoints relevant to device efficacy studies.
- Supports continuity from discovery-stage ablation profile optimization to preclinical validation of visual outcomes.
- Informs risk-adjusted advancement decisions based on statistically significant improvements in visual function.
Pipeline & Workflow Integration
This method integrates into the discovery-to-preclinical continuum for ophthalmic device R&D, bridging early hypothesis testing with quantitative outcome validation.
- Discovery Biology: Quantifies visual acuity and corneal aberration changes to clarify device mechanism and biological impact.
- Screening: Standardizes outcome measures for reproducible comparison of ablation profiles and device settings.
- Analytics: Provides statistical outputs (e.g., Z-scores, p-values) to support data-driven decision making.
- Translational Research: Aligns objective visual quality metrics with preclinical and clinical endpoints.
- Enterprise Reuse: Establishes a reusable framework for evaluating future refractive correction technologies.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence and reduces mechanistic ambiguity in device performance.
- Operational Value: Enables standardized, reproducible measurement of visual and corneal outcomes.
- Strategic Value: Supports informed go/no-go decisions and capital-efficient advancement of refractive technologies.
- Portfolio Impact: Facilitates risk-adjusted prioritization of device candidates based on quantitative efficacy data.
Implementation Considerations
- Requires expertise in ophthalmic surgery and quantitative visual assessment.
- Needs access to corneal imaging, aberration analysis, and statistical data infrastructure.
- Demands cross-team standardization of measurement protocols and data interpretation.
- May require adaptation of outcome metrics for different patient populations or device platforms.
- Practical limitations include sample size and generalizability to broader clinical settings as noted in the study.
