A new ultrafast laser method that reshapes a small part of the cornea may be effective in treating presbyopia, the blurry near vision that people develop around age 40.
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Surgical treatments for presbyopia are gaining popularity with recent FDA approvals of two types of corneal inlays, tiny lenses or optical devices that are inserted into the cornea to improve reading vision. However, one of the potential drawbacks of synthetic inlays is the patient's eye rejecting the artificial material. Recognizing this, a researcher at Dr. Agarwal's Refractive and Cornea Foundation (Chennai, India) has developed an approach that uses a femtosecond laser to extract a disc of corneal tissue, which is then sculpted. This treatment may offer safety advantages over synthetic corneal inlays for presbyopia, as it uses the person's own more biologically compatible corneal tissue.
The PrEsbyopic Allogenic Refractive Lenticule (PEARL) technique to correct presbyopia involves the use of femtosecond lasers, which provides the ability to shape cornea with high precision. The PEARL procedure uses the laser to make a small cut in the cornea, the clear round dome at the front of the eye. A disc of corneal tissue, called a lenticule, is removed through this cut, using a technique called small incision lenticule extraction (SMILE). The SMILE technique permanently removes this tissue to reshape the eye and correct vision. In PEARL, the SMILE lenticule is cut to 1 mm and reshaped. This newly created inlay is placed into a pocket in the cornea of the presbyopic patient to improve near vision without significantly compromising distance vision.
Unlike current treatments for presbyopia that involve using a synthetic inlay to improve near vision, PEARL uses human corneal tissue. This reduces complications, including potential inflammation. In comparison to synthetic inlays, the PEARL inlay is expected to allow better oxygen and nutrient flow through the patient's cornea. A similar technique using human corneal tissue has already been used to treat other eye conditions, such as farsightedness.
In the study, researchers implanted inlays in the eyes of six patients. Recipients were tested within one week of having the procedure. Near visual acuity was measured using the Jaeger Eye Chart, a handheld card with lines of type that get increasingly smaller. When holding the chart 33 cm away, all showed improvement in uncorrected near vision of three to five lines. The researchers followed all of the patients for at least four months, and found that their vision remained stable. They also noted that, in those with reduced distance vision, LASIK can be performed at the same time as PEARL.
"The PEARL inlay changes the shape of the cornea to improve near vision," says Soosan Jacob, MD, FRCS, DNB, lead author and creator of the procedure who is also director and chief of Dr. Agarwal's Refractive and Cornea Foundation, and senior consultant of Cataract and Glaucoma Services at Dr. Agarwal's Group of Eye Hospitals. "Because it's made of human corneal tissue, the inlay remains stable. Our preliminary findings have been very promising."
Results of the work were presented at AAO 2016, the 120th annual meeting of the American Academy of Ophthalmology (October 15-18, 2016, in Chicago, IL). For more information, please visit www.aao.org.