One treatment for presbyopia that has garnered much attention is intraCOR, or intrastromal correction of presbyopia. At the 2008 Royal Hawaiian Eye meeting in Kona, Hawaii, Luis Antiono Ruiz, MD, of Columbia, announced his promising initial results with this procedure. His novel, noninvasive technique successfully reshaped the cornea and redistributed the biomechanical forces necessary for presbyopia correction. To date, he has treated more than 1,000 eyes with intraCOR. The University of Heidelberg is currently participating in a multicenter European study to further test the safety and stability of this treatment.
Until recently, laser procedures for presbyopia correction required the creation of an opening into the cornea and removal of the epithelium to apply treatment to the deeper stroma. However, the intraCOR presbyopia treatment with the Femtec femtosecond laser (20/10 Perfect Vision, Heidelberg, Germany) changes that. We now have the ability to focus the treatment directly into the stroma, without cutting the cornea or creating an intrastromal pocket. Additionally, this intrastromal correction does not require removal of the epithelium. Therefore, the structural integrity of the cornea is maintained. IntraCOR has a minimal rate of infection and promotes wound healing.
Another advantage to intraCOR is the quick procedure time; presbyopia correction lasts approximately 20 seconds. During intraCOR, gas bubbles initially form in the cornea, and the patient's vision is blurred for 2 to 3 hours. When the bubbles dissolve, the cornea clears, distance visual acuity returns, and the patient immediately notices the change in near visual acuity. By 1 day postoperative, the majority of patients experience a gain in near visual acuity.
Currently, we are participating in an ongoing multicenter study to confirm the initial results with intraCOR. At the University of Heidelberg, we currently have 3-month follow-up for 25 patients (age range, 48–66 years) treated since July 2008. All patients received the treatment in their nondominant eye, with a minimum near add of 2.00 D. Figure 1 depicts what the eye looks like 1 hour and 1 day after intraCOR treatment.
The mean preoperative spherical equivalent in these 25 eyes was 0.62 ±0.28 D, and the mean preoperative sphere and cylinder were 0.78 ±0.26 D and -0.33 ±0.19 D, respectively. Distance and near UCVA were 0.13 ±0.13 and 0.70 ±0.17 logMAR, respectively.
Postoperative results are good, with a mean gain of near visual acuity from 20/100 to 20/30. This confirms Dr. Ruiz's earlier results. In our center, patients gained up to six lines of near visual acuity, and no patient lost any lines of near visual acuity. All near reading tests were performed with charts.
Most patients achieved good near visual acuity and did not require the use of reading spectacles; however, patients confirmed that ideal lighting conditions are needed to read well. This is similar for other presbyopia correction methods, such as multifocal IOLs.
IntraCOR is a promising treatment option for presbyopic patients and for patients with lower amounts of myopia or hyperopia. In contrast to many other surgical procedures, the complete intrastromal ablation pattern is created without any need of cutting the corneal surface, which minimizes potential risks of infection.
Mike P. Holzer, MD, is a faculty member, Cataract, Cornea, and Refractive Surgery, at the International Vision Correction Research Centre, Department of Ophthalmology, University of Heidelberg, Germany. Dr. Holzer states that he is a clinical investigator for 20/10 Perfect Vision AG. He may be reached at e-mail: Mike.Holzer@med.uni.heidelberg.de.