Corneal Refractive Therapy (CRT) 

Experience freedom from the hassles of glasses and daytime contacts, without surgery. 


What is Corneal Refractive Therapy?

Corneal Refractive Therapy ("CRT") is a non-surgical treatment that corrects myopia (nearsightedness) and astigmatism (out of round corneal surface) using the overnight wear of treatment lenses. The lenses gently reshape your corneas while asleep. Upon waking, and removing the lenses, you will experience clear and natural distance vision, without glasses or contact lenses throughout the day.

In a myopic (nearsighted) eye, light from a far away object is focused in front of the retina, resulting in blur. In essence, the eye is too strong for itself. Traditional spectacle lenses change the direction of light before it enters the eye, allowing for the image to be focus on the retina for clear vision.

Corneal refractive therapy works by altering the eye's power, allowing light to be precisely focused on the retina without the use of standard lens corrections. Unlike refractive surgery (LASIK), CRT is temporary, as continual use of nighttime treatment lenses is necessary to maintain its effect. We have found CRT to be an exciting new option for individuals seeking the freedom from the daytime use of eyeglasses or contact lenses. It is an especially attractive option for those that are either apprehensive about or not a candidate for refractive surgery.

Beyond a comprehensive eye examination, the following outlines the basic steps involved in the CRT process:


CRT Lens Design and Initial Fitting
A corneal topography will be performed to determine the shape of your cornea and assist in the selection of an initial diagnostic CRT lens. If necessary, additional diagnostic lenses will be tried until we obtain the ideal corneal-treatment lens fitting relationship. It is believed that the CRT effect occurs in the corneal epithelium, which is the top layer of the cornea. The treatment lens is specifically designed to alter the shape of this tissue. As illustrated in this cross section view to the right, the treatment lens is flatter than the cornea at its center and takes a plateau shape towards its periphery.

Lenses will either dispensed from our in-house inventory or ordered from the manufacturer and you will be scheduled for a progress evaluation following the first night of treatment lens wear.

CRT Lens Wear
While wearing the CRT lens, the surface differences, between the lens and the cornea, forces the cornea (epithelium) to take on a new shape. Research is underway to determine just how the new corneal shape is created. It is believed that with lens induced pressures the epithelium either migrates from the corneal center or that the epithelium becomes compressed. In either case, the corneal tissue begins to take on the shape of the treatment lens back surface, which is designed to correct for myopia and astigmatism.

CRT Lens Removal
Following overnight wear, the CRT lens is removed revealing a new corneal surface shape. It has been our experience that the first night of wear will correct approximately 50 to 60 % of the treatment goal. You should notice improved vision, however, the effect will fade quickly. Then, with every successive night of wear, the effect will become greater and will last longer. We expect that it will take between 7 to 14 days of treatment to obtain useful vision throughout your day. We have found that age and the degree of the pre-treatment refractive error are the primary factors controlling how quickly the treatment become effective.


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