Toric implantable collamer lens (ICL) devices display better astigmatism correction than conventional ICLs combined with a limbal relaxing incision (ICL-LRI), according to a study published in BMC Ophthalmology. The approaches are comparable in their myopia-correction capabilities, the report indicates.
Researchers analyzed records of 40 eyes of 28 participants that were fit with a toric implantable collamer lens, and 40 eyes of 27 patients who underwent the combined ICL-LRI procedure between September 2021 to September 2022.
Both approaches comparably affected manifest sphere and cylinder, visual acuity, and intraocular pressures (all P >.10). Using Alpins technique to evaluate corneal vectors, surgically-induced astigmatism (SIA) in the toric group largely persisted for 6 months (P =.420), compared with reduced SIA for ICL-LRI patients (P =.001).
Patients who received a toric implantable collamer lens demonstrated higher SIA after 1, 3, and 6 months than those who underwent the ICL-LRI procedure (1.68 vs 1.17 at month 6; P =.010)
At 6 months, both surgeries demonstrated that their intended effects are maintained at 6 months, although neither implantable collamer lens approach was able to achieve perfect astigmatism correction.
The researchers report that the results of their investigation confirm that the shape of the cornea and the degree of astigmatism are not changed immediately after LRI surgery.
“Although the cornea is relaxed quickly in the first several days after LRI surgery, the shape of the cornea takes at least a month to stabilize,” researchers wrote, adding that SIA decreasing with time may signal lessened long-term correction, or under-correction with LRI. Conversely, slight drawbacks of the implantable collamer lens can be a longer wait for lenses, 2% repositioning risk, and expense.
This study was limited in retrospective study design and single-center nature. It also focused on patients with regular astigmatism and less than 10° difference between the steepest meridian of astigmatism and the corneal K2 axis.
Disclosure: One study author declared affiliations with the biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Yang K, Li J, Zhang W, et al. Implanting toric implantable collamer lens displays better astigmatism correction than implantable collamer lens combined with manually limbal relaxing incision. BMC Ophthalmol. Published online May 5, 2023. doi:10.1186/s12886-023-0294-1