What Is V-Toric ICL? A New Approach to Astigmatism Correction
Summary
V-Toric ICL is a specialized toric ICL approach for patients who need correction of both myopia and astigmatism. Unlike conventional toric ICL implantation, which generally positions the lens horizontally, V-Toric ICL uses vertical implantation based on the eye's internal anatomy.
Because astigmatism correction depends on precise lens alignment, this approach aims to improve rotational stability while maintaining an appropriate postoperative vault.
For patients with high myopia and astigmatism, achieving clear vision involves more than simply correcting nearsightedness. Surgeons must also accurately correct and maintain astigmatism orientation after surgery.
But why does ICL direction matter? To understand the purpose of V-Toric ICL, first understand astigmatism and how a toric ICL corrects it.
What Is Astigmatism?
Astigmatism is a common refractive error caused by the eye's optical surface not having perfectly symmetrical curvature. Instead of light focusing evenly at a single point, it may focus differently depending on its orientation. This can make objects appear blurred, stretched, doubled, or distorted at different distances.
Astigmatism also has a specific orientation, known as the axis of astigmatism. This matters when using a toric lens because its astigmatic correction must stay aligned with the patient's intended axis.
Why Do Patients with Astigmatism Need a Toric ICL?
Many patients with severe myopia also have significant astigmatism. High myopia can make laser refractive surgery such as LASIK, LASEK, or SMILE less suitable. For example, when the required correction would involve removing a relatively large amount of corneal tissue, an Implantable Collamer Lens (ICL) may be considered.
Unlike laser vision correction, ICL surgery does not reshape the cornea. Instead, a thin implantable lens is positioned inside the eye, between the iris and the natural crystalline lens.
For patients who need both myopia and astigmatism correction, a toric ICL can be used. The toric ICL provides cylindrical correction tailored to the patient's astigmatism, so its orientation inside the eye matters.
Why Is Toric ICL Rotation Important?
Think of it like wearing glasses crooked. Even if the prescription is correct, the lenses aren't properly aligned with your eyes, which can affect how clearly you see.
A similar principle applies to a toric ICL. The lens must remain aligned with the planned astigmatic axis to provide the intended correction. If it rotates significantly after surgery, its cylindrical correction becomes misaligned.
As a general optical principle, approximately 3% of the astigmatic correcting effect is lost for every 1° of toric lens misalignment. For example, a 10° misalignment can reduce the intended astigmatic correction by roughly 30%.
This is why rotational stability matters most for patients with higher degrees of astigmatism.
What Is V-Toric ICL?
V-Toric ICL is a surgical technique developed at Seoul | Busan BGSS Eye Clinic in which a toric ICL is implanted vertically rather than in the conventional horizontal orientation.
Traditionally, ICLs have generally been positioned horizontally inside the posterior chamber of the eye. However, the visible shape of the eye does not necessarily reflect the dimensions of the internal space where the ICL is positioned. Research on the posterior chamber has shown that its vertical dimensions can exceed its horizontal dimensions in many eyes.
Based on extensive experience with ICL surgery and research on postoperative lens positioning, we developed the V-Toric technique to account for these anatomical characteristics. Surgical planning accounts for the patient's internal ocular dimensions, lens size, expected vault, astigmatic correction, and intended lens orientation.
V-Toric ICL vs. Conventional Toric ICL
Both conventional toric ICL surgery and V-Toric ICL can correct myopia and astigmatism. The key difference is toric lens orientation: conventional implantation generally positions it horizontally, while V-Toric uses vertical implantation.
Although this difference may appear small, lens orientation can influence how the ICL fits within the posterior chamber and its resistance to postoperative rotation.
Clinical research evaluating vertically and horizontally implanted toric ICLs has examined factors including postoperative rotation, vault, refractive outcomes, and visual acuity. Research from BGSS Eye Clinic comparing the two orientations reported an average postoperative rotation of about 1° with vertically implanted toric ICLs, compared with about 3° with horizontally implanted toric ICLs.
Reducing postoperative rotation may therefore help maintain more predictable astigmatism correction.
How Does V-Toric ICL Improve Lens Stability?
One of the main goals of V-Toric ICL is to improve rotational stability without simply choosing an excessively large lens to restrict movement.
ICL sizing is also important because the implanted lens must maintain an appropriate distance from the natural crystalline lens. This distance is known as the vault. A vault that is too high or too low may increase the risk of complications, so careful preoperative measurements and lens-size selection are essential.
V-Toric planning therefore considers both rotational stability and postoperative vault. By evaluating the eye's internal dimensions and positioning the toric ICL vertically when appropriate, the technique aims to achieve a stable lens position while maintaining a suitable vault.
Who May Be a Candidate for V-Toric ICL?
V-Toric ICL may be considered for patients with both myopia and clinically significant astigmatism who are otherwise suitable candidates for ICL surgery.
It may be particularly relevant for patients with high myopia who are not ideal candidates for corneal laser vision correction because of their prescription, corneal characteristics, or other anatomical factors.
However, having myopia and astigmatism does not automatically mean that V-Toric ICL is appropriate. A comprehensive examination should evaluate:
Degree of myopia and astigmatism
Astigmatic axis
Corneal shape and thickness
Anterior chamber depth
Internal ocular dimensions
Endothelial cell density
Expected postoperative vault
Overall ocular health
These measurements help the ophthalmologist determine whether ICL surgery is appropriate and plan the lens size, power, and orientation for each individual eye.
Can a V-Toric ICL Still Rotate?
V-Toric ICL is designed to improve rotational stability, but no implanted lens can be guaranteed to remain completely motionless.
Patients should follow their ophthalmologist's postoperative instructions carefully, including avoiding eye rubbing and direct trauma, and following recommendations regarding exercise, swimming, contact sports, and other strenuous activities during recovery.
If vision becomes noticeably blurred or distorted after initially being clear, contact your ophthalmologist for an examination. Your ophthalmologist can check the ICL's position and axis to determine whether lens rotation or another postoperative issue is responsible.
Frequently Asked Questions About V-Toric ICL
What is V-Toric ICL?
V-Toric ICL is a toric ICL implantation technique that uses vertical lens positioning to improve rotational stability while correcting myopia and astigmatism.
What is the difference between V-Toric ICL and a regular toric ICL?
The primary difference is lens orientation. Conventional toric ICLs are generally implanted horizontally, while the V-Toric technique uses vertical implantation based on the eye's internal anatomy and surgical measurements.
Can V-Toric ICL correct both myopia and astigmatism?
Yes. The toric ICL corrects both myopia and astigmatism, while the V-Toric technique focuses on lens positioning and rotational stability.
Why is rotation important after toric ICL surgery?
A toric lens must remain aligned with the intended astigmatic axis. As it rotates away from this axis, its astigmatic correction becomes less effective.
What happens if a toric ICL rotates after surgery?
Significant rotation may cause residual astigmatism, blurred or distorted vision, or reduced visual quality. An ophthalmologist can evaluate the lens position and determine whether additional treatment or repositioning is necessary.
