What are Phakic Intraocular Lenses?
Phakic intraocular lenses are designed to correct a patient’s vision by inserting an intraocular lens inside the eye without removing the patient’s natural human lens. It is typically used in people who have moderate to high amounts of myopia. This is especially for people who are highly nearsighted and are not candidates for LASIK. There are phakic intraocular lenses being developed for astigmatism and hyperopia.
Most intraocular lenses are used during cataract surgery where the cloudy human lens is removed and replaced with an intraocular lens. There are many types of lenses and they can reduce and/or eliminate the need for glasses or contacts.
A new phakic intraocular lens called the Alcon AcrySof Cachet Lens is finishing Phase I and phase II five year clinical trials.
The Acrysof Cachet lens is designed to be placed inside the anterior chamber of the eye. The anterior chamber is the fluid-filled space between the iris (colored portion of the eye) and the cornea (clear front portion of the eye).
It has a four-point haptics design which allows the lens to rest in the angle of the eye. This is located where the cornea and the iris meet at the sclera (white portion of the eye). It is engineered so that it rests inside the eye in a safe manner. The lens comes in four different sizes in order to fit a variety of different sized eyes.
The vaulted design allows eye surgeons the freedom of not performing laser iridotomies or iridectomies.
The AcrySof Cachet lens has a power range from -6.00 diopters to -16.5 diopters in 0.5 diopter steps.
Clinical Trial Results from 2008
Raised IOP requiring treatment 2.8%
Cataract formation 1.9%
Corneal haze 0.3%
Best corrected vision loss 0.3%
No pupil ovalization greater than 1mm
No instances of intraocular lens dislocation
No retinal detachments or repairs
No pupillary block
Five patients were hospitalized for increased intraocular pressure due to retained viscoelastic used during surgery. This was not related to the intraocular lens.
One patient had the lens removed.
The average refractive error for patients was -10.4 diopters
Patients with 20/20 corrected pre-op had 20/25 or better uncorrected (vision without glasses or contacts) in over 86% of cases at three years.
The Alco AcrySof Cachet Intraocular Lens is a very promising phakic lens for use in patients of moderate to high myopia with few complications and excellent visual results