11-Year Study of More Than 10,000 Patients Confirms the Safety of ICL Lens Exchange
Dr. Hannuy Choi, the representative director of B&VIIT Eye Center, presented a groundbreaking study at the 2026 American Society of Cataract and Refractive Surgery (ASCRS) Annual Meeting, one of the world’s most prestigious ophthalmology conferences.
The research analyzed corneal endothelial cell changes following Implantable Collamer Lens (ICL) exchange using data collected from approximately 10,779 patients over an 11-year period. Due to its scale and long-term follow-up, the study is considered one of the largest of its kind worldwide and provides valuable clinical evidence regarding the safety of ICL lens exchange procedures.
What Is ICL Surgery?
ICL (Implantable Collamer Lens) surgery is a vision correction procedure that improves eyesight by implanting a biocompatible lens between the iris and the eye’s natural lens without removing corneal tissue.
Because the cornea remains untouched, ICL surgery is often recommended for patients with:
- High myopia (severe nearsightedness)
- Thin corneas
- Patients who may not be suitable candidates for LASIK or LASEK
One of the unique advantages of ICL surgery is that the lens can be removed or exchanged if necessary, making it a reversible and manageable vision correction option.
When Is an ICL Exchange Needed?
Although ICL lens exchange is relatively uncommon, there are several situations where it may be recommended:
1. Vault-Related Issues
The vault refers to the space between the implanted lens and the eye’s natural lens. If the vault is too high or too low due to lens sizing or individual eye anatomy, lens exchange may be necessary.
2. Changes in Prescription
Some patients may experience vision changes over time and require a different lens power.
3. Upgrading to a More Suitable Lens
In certain cases, replacing the existing lens with a newer or more appropriate lens can improve visual outcomes.
Despite the benefits of lens exchange, concerns have long existed regarding potential damage to corneal endothelial cells during the removal and reinsertion process.
Corneal endothelial cells are essential for maintaining corneal clarity and transparency. Since these cells do not regenerate, preserving them is a critical consideration in any intraocular procedure.
What Did the 11-Year Study Find?
The study focused on patients who underwent bilateral ICL surgery but required lens exchange in only one eye.
Researchers compared changes in corneal endothelial cell density between:
- The eye that underwent lens exchange
- The fellow eye that retained the original lens
The results showed no statistically significant difference in endothelial cell changes between the two eyes.
These findings challenge the common concern that endothelial cell damage is unavoidable during ICL exchange procedures.
Surgical Expertise Matters
Commenting on the study, Dr. Choi explained:
“With careful surgical technique and sufficient experience, endothelial cell loss during lens exchange can be minimized. A thorough understanding of intraocular anatomy and precise surgical skills play a crucial role during both lens removal and reinsertion.”
The study highlights the importance of surgeon experience and meticulous surgical planning in maintaining safety during ICL exchange procedures.
Why Long-Term Clinical Data Matters
This presentation serves as a follow-up to Dr. Choi’s research presented at ASCRS 2025, marking the second consecutive year that B&VIIT Eye Center has demonstrated the safety of ICL surgery through data at the world’s largest refractive surgery conference.
The achievement reflects B&VIIT’s commitment to maintaining and analyzing one of Korea’s most extensive long-term databases of ICL patients, with more than 10,000 cases tracked over many years.
Continuing to Advance ICL Surgery
The success of ICL surgery depends not only on advanced technology but also on the surgeon’s experience and access to long-term clinical data.
Dr. Choi has performed more than 20,000 vision correction procedures, including SMILE Pro laser vision correction and EVO ICL surgery. She continues to conduct research aimed at improving patient safety and developing predictive guidelines that may help identify patients who could benefit from lens exchange in the future.
At B&VIIT Eye Center, ongoing research, AI-based precision analysis systems, and extensive clinical experience continue to drive innovation in vision correction surgery and improve outcomes for patients from around the world.