The term “permanent contact lenses” refers to two distinct options: external lenses worn for extended periods, and internal lenses surgically implanted for lasting vision correction. This article explores both the non-surgical option, which offers extended wear, and the surgical alternative, which provides decades of clear vision without daily maintenance.
The Misconception: Extended Wear Lenses
The most common interpretation of “permanent contact lenses” involves external lenses designed for extended wear, which can be worn continuously for multiple days or weeks. These lenses are made from highly breathable silicone hydrogel materials that allow greater oxygen transmission to the cornea. However, these are not permanent solutions and must be removed periodically for cleaning and disinfection, typically on a weekly or monthly schedule.
The primary risk associated with extended wear lenses is a significantly increased chance of developing microbial keratitis, a serious corneal infection. Wearing any contact lens overnight can increase the risk of this infection by 10 to 15 times compared to wearing daily disposable lenses. The warm, moist environment under the lens allows bacteria like Pseudomonas aeruginosa to thrive and multiply. Microbial keratitis can lead to severe pain, vision impairment, and, in the most serious cases, permanent sight loss or the need for a corneal transplant.
True Permanent Correction: Implantable Lenses
True permanent vision correction is achieved through a surgical option known as Phakic Intraocular Lenses (PIOLs), often called Implantable Collamer Lenses (ICLs). These devices are thin, biocompatible lenses surgically placed inside the eye, typically between the iris and the eye’s natural lens. PIOLs do not replace the natural lens, which is why they are called “phakic” lenses.
The ICL procedure is designed to provide stable, high-definition vision correction that is intended to last a lifetime. This technology is particularly beneficial for individuals with high degrees of myopia (nearsightedness) or those with thin corneas. The lens material, often a flexible collagen copolymer, is designed to work harmoniously with the eye’s internal structures. By adding a corrective lens internally, PIOLs function much like an invisible, maintenance-free contact lens, providing a permanent focus adjustment.
Comparison to Laser Vision Correction
Implantable Collamer Lenses offer distinct advantages when compared to laser vision correction procedures, such as LASIK and PRK. The most significant difference is that the ICL procedure does not involve the permanent removal or reshaping of corneal tissue. LASIK and PRK use an excimer laser to ablate precise amounts of tissue from the cornea to correct the refractive error.
ICLs are generally considered reversible, meaning the lens can be surgically removed or replaced if a patient’s vision changes significantly. Laser procedures, however, are irreversible because the corneal tissue has been permanently altered. This distinction makes ICLs a suitable option for individuals with thin corneas who may not be candidates for LASIK. While LASIK and PRK are typically less expensive, the upfront cost of an ICL procedure is higher, reflecting the advanced technology and the custom-manufactured implant.
Suitability, Procedure, and Long-Term Care
Candidacy for ICL surgery requires a thorough eye examination to ensure the patient meets specific health and anatomical criteria. Patients must typically be between 21 and 45 years old with a stable prescription for at least a year, and have sufficient anterior chamber depth. The natural lens must also be healthy, as the presence of the ICL can, in rare cases, increase the risk of early cataract formation over time.
The ICL implantation is a quick, outpatient procedure, often taking less than 30 minutes per eye. The lens is carefully folded and inserted through a small micro-incision. Recovery is generally rapid, with many patients noticing significant vision improvement within the first day. While the lens is designed to be permanent, long-term monitoring is required, including regular check-ups to measure intraocular pressure and confirm the proper positioning of the lens. Potential long-term risks include increased eye pressure (glaucoma) and visual artifacts like halos or glare around lights.