There are several paths an optometrist can take when determining the best visual correction for their patients. The best option depends on the patient’s individual goals. Some patient’s desire greater flexibility with their correction, in which case glasses or contact lenses may be the best option. Others desire a solution with greater permanence indicating that refractive surgery is best. It is important to keep in mind, however, that not all patients are good candidates for surgical treatment.
Certain pathological risks such as keratoconus, excessive refractive error, and dry eye can all be contraindications for surgery of all types. However, it is important to keep in mind there are alternatives to classic surgical options. Such options can lead to better outcomes and greater patient satisfaction when compared to traditional refractive surgery such as PRK or LASIK.
Implantable Collamer Lens (ICL)
Candidates of a standard ICL lens are those that are highly myopic with a prescription range of -3.00 D to -15.00 D, a safe vault size, and healthy endothelial cell density. This lens is also available in a toric version (TICL). Candidates for the TICL are those with a cylinder range from -1.00 D to -8.00 D. Benefits to ICL/TICL are sharper vision both morning and night in comparison to the LASIK. The vault is measured to accommodate variation in the intraocular anatomy, which is critical to the potential outcome of each patient. The implant also contains a UV filter made from an absorbent material blocking out harmful sunlight. This surgery has been shown to have less impact on the integrity of the cornea, and less dryness post surgery resulting in more stable visual outcomes. Research has shown that an ICL lens compared to photo-refractive keratectomy is superior in safety, effectiveness, consistency, and overall quality of life.
Anatomically, the implant is placed within the posterior chamber of the eye; behind the iris and in front of the crystalline lens. Equipment such as the Pentacam, Lenstar, and Visante are used measure the horizontal corneal diameter and anterior chamber depth to calculate the size of the implant. Once the data is collected, the surgeon determines the best plan for the patient to ensure the best possible outcome.
Post-operative care is delivered either by the refractive surgeon or the patient’s primary optometrist. Yearly dilated exams are recommended to monitor the results as well as the health of the eye, although complications are rare (less than two percent of cases result in complications). Complications may include pigment dispersion, premature cataracts, or glaucoma. In addition, there are rare instances where the lens rotates outside of a five degree tolerance and must be surgically manipulated.
With the advent of the latest advances in ICL and TICL technology, patients and their doctors have even more options to provide life changing refractive surgeries.
Caceres, Vanessa. “Making Room in the Toolbox for the Toric ICL.” EyeWorld, Ophthalmology News – EyeWorld Magazine 283 110, 5 Mar. 2019, eyeworld.org/making-room-toolbox-toric-icl.
Packer, Mark. “Meta-Analysis and Review: Effectiveness, Safety, and Central Port Design of the Intraocular Collamer Lens.” Clinical Opthalmology, Dove Press, 2016, www.dovepress.com/.