Study demonstrates improvement in reading vision after implantation of the Kamra Corneal Inlay. The pros and cons of this approach in comparison to blended monovision LASIK need further study in patients who need reading glasses. Presbyopia, or the need for reading glasses, clearly affects reading performance. One potentially helpful technology to address presbyopia is currently undergoing FDA clinical trials: the Kamra (Acufocus) corneal inlay. The Kamra inlay involves placing a very small aperature, similar to a “pinhole” in the center of the cornea to help focus light better for close vision and reading.

A recent study from Austria showed of 24 emmetropic presbyopic patients (patients who were neither nearsighted nor farsighted — but who just needed reading glasses) demonstrated significantly improved reading performance after implantation of the Kamra corneal inlay in their non-dominant eyes.

Two years after the corneal inlay was implanted, subjects were evaluated for reading visual acuity using both eyes without glasses, reading distance, average and maximum reading speed, and the smallest print size that could be read.

Results showed improvement in most of these parameters after the Kamra corneal inlay was implanted. Average reading distance improved from 46.7 cm to 39.5 cm. Average reading acuity improved from 0.33 to 0.22 logRAD. Smallest print sized improved from 1.5 mm to 1.0 mm. Improvements were more pronounced in bright light. Average reading speed and maximum reading speed were not changed, however.

These results are good, but they are not necessarily that different from what can be achieved with small degrees of monovision called “blended” monovision vision that can be achieved with LASIK, but without the corneal inlay. In blended monovision, the dominant eye is set for distance and the non-dominant eye is set for mid range focus. This is different from “full” or “classical” monovision in which the non-dominant eye is set for close vision, creating more of a disparity between the two eyes. The degree of near vision improvement with blended monovision vision, depending on the patient’s age, typically is at least as good as seen in these results of the Kamra corneal inlay. However, there is one difference. With the Kamra inlay, the distance vision in the non-dominant eye is better than the distance vision is in the mid range, non-dominant eye of blended monovision. This may or may not be an important real world difference as blended vision still allows the brain to “synthesize” both eyes and give excellent distance vision when both eyes are used together. Certainly, blended monovision works extremely well for many LASIK patients who otherwise would need reading glasses due to their age. Further studies will be necessary to determine the pros and cons of using the Kamra corneal inlay as an alternative to blended monovision LASIK.

See Also

Reading Performance and Patient Satisfaction after Corneal Inlay Implantation for Presbyopia Correction: Two Year Follow-up
A Study of Reading Distance and Reading Vision Improvement after Kamra Corneal Inlay Implantation

Reading Performance Improves After Implantation of Corneal Inlay
Reading parameters improved in emmetropic, presbyopic patients two years following Kamra corneal inlay implantation

The Acufocus Kamra
Company website for the Acufocus Kamra Corneal Inlay

Corneal Inlays and Onlays
Blog discussing corneal inlays and onlays.

Corneal Inlays Have Reached a Tipping Point
International Society of Refractive Surgery discussion of corneal inlay technologies

Presbyopia: Intracorneal Inlays May Be Preferred
EyeWorld (American Society of Cataract and Refractive Surgery) article about corneal inlays.

The Corneal Route for Treating Presbyopia
A discussion about using corneal inlays to correct presbyopia instead of using intraocular presbyopia correcting premium lenses

Presbyopia
A discussion of presbyopia, the age related loss of the ability to see up close.

Presbyopia
Mayo Clinic site on the need for reading glasses (presbyopia).

Presbyopia
National Institutes for Health (NIH) discussion of the need for reading glasses due to aging of the eye.