Many college students are planning vision correction surgery during summer break.
Most choose laser procedures such as SMILE LASIK or SMILE Pro, but some have no alternative other than implantable collamer lens (ICL) surgery because they have extremely high myopia or corneal conditions that are not suitable.
The key to phakic intraocular lens implantation, which is known to be safe because it does not remove corneal tissue, lies in the precise design of the space inside the eye. Long-term safety 10 or 20 years later depends on the distance the implanted lens maintains from surrounding tissues such as the crystalline lens and iris. For that reason, phakic intraocular lens implantation requires far more precise and complex preoperative tests than laser surgery.
The first is an endothelial cell test, which determines whether surgery is possible. The endothelial cells on the inner surface of the cornea do not regenerate once damaged, so surgery cannot proceed if the cell count falls below the standard. Even after surgery, lifelong regular monitoring is necessary for safety.
The second is a gonioscopy to check the aqueous humor drainage pathway. If the drainage angle where the iris and cornea meet is narrow, or closed-angle, inserting the lens can block the opening and trigger acute glaucoma. Therefore, the angle of the drainage pathway must be examined directly and precisely with a special mirror lens.
The third is a 3D anterior segment scan using Cassia 2. By creating a 360-degree stereoscopic model of the anterior segment, it predicts the space available for the lens and the flow of aqueous humor, helping to preempt potential complications such as glaucoma and cataracts.
Finally, a cycloplegic refraction test is used to find the eye's true prescription. In younger patients with strong accommodative power, a "false myopia" reading can appear under tension, so the lens power must be calculated accurately after medication temporarily paralyzes accommodation.
If a complete blueprint has been prepared through thorough testing, turning it into reality depends on the medical team's skilled technique. The clinic's proprietary SSVC ICL, a combined astigmatism-correction lens implantation procedure, can improve the accuracy of astigmatism correction.
In general, severe astigmatism is treated with a toric lens, but if the lens rotates slightly inside the eye, visual acuity can decline.
At the author's ophthalmology clinic, astigmatism is first corrected with a corneal microincision method, and myopia is then treated with a standard lens, eliminating rotation problems at the source.
In one actual case, a patient who had failed five reoperations at another hospital because of toric lens rotation regained stable vision in a single procedure through the SSVC method. Of course, if astigmatism is extremely high and exceeds a certain threshold, a toric lens must be used. In such cases, the optimal type is determined by analyzing the patient's ocular condition data and choosing either a vertical V-Toric or a horizontal H-Toric, achieving correction without error.
As a result, the clinic has secured the nation's first 10-year long-term follow-up clinical data on phakic intraocular lens implantation. This demonstrates how conservative and precise the safety standards for ICL surgery are. Based on tens of thousands of accumulated cases, the clinic determines the lens size and surgical position that best fit each patient's eye structure. This is why precious vision must be protected through a combination of scientific evidence and extensive clinical experience.
Courtesy of Director Kim Boogi of Onnuri Smile Ophthalmic Clinic
