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Computational Modeling of Ophthalmic Procedures: Computational Modeling of Ophthalmic Procedures
William J Foster1, Brian W Berg2, Steven N Luminais2
1From the Department of Bioengineering (W.J.F.), Lewes Katz School of Medicine (B.W.B., S.N.L.), Temple University, Philadelphia, Pennsylvania, USA; Altasciences, Montréal, Québec, Canada (W.J.F.).
American Journal of Ophthalmology
|March 31, 2022
Summary
Finite-element calculations reveal that smaller needles increase retinal stress during intravitreal injections, potentially causing tears. Stress is concentrated at the edge of retinal pigment epithelial detachments, posing a significant risk.
Area of Science:
- Ophthalmology
- Vision Science
- Biomechanical Engineering
Background:
- Computational models offer critical insights into surgical procedure physics.
- Understanding biomechanics is crucial for surgical safety and efficacy.
Purpose of the Study:
- To model retinal stress during intravitreal injections using finite-element analysis.
- To investigate the impact of needle gauge on retinal force.
- To determine stress distribution on retinal pigment epithelial detachments.
Main Methods:
- Finite-element calculations performed using COMSOL Multiphysics.
- Comparison with monkey retinal adhesive force (18 Pa) to quantify stress.
- Simulation of intravitreal injection forces and stress concentrations.
Main Results:
- Current 30-gauge needles generate retinal stress near the threshold for tears.
- Smaller gauge needles significantly increase retinal stress.
- Stress on retinal pigment epithelial detachments localizes to the edge, sufficient to cause tears.
Conclusions:
- Physicians should be aware of increased retinal tear risk with smaller needles.
- Stress concentration at the edge of RPE detachments is a critical factor in tear formation.
- Findings can inform clinical practice and future research in intravitreal injections.
