Physician perspective: ORA and my results with a glistening-free IOL

By P. Dee G. Stephenson, MD, FACS, Special to Ophthalmology Times

Glistenings-fluid-filled micro vacuoles that develop in some IOLs-are most common in hydrophobic acrylic IOLs and can cause backscatter and frontscatter.

They may have a negative effect on vision and contrast sensitivity, despite excellent Snellen acuity measurements.^1,2,3

In an attempt to eliminate glistening, I tried an aspheric glistening-free IOL (enVISTA, Bausch + Lomb) made of a highly cross-linked hydrophobic acrylic co-polymer with a high refractive index of 1.54. The IOL is pre-hydrated and packed in 0.9% saline and brought to equilibrium before packaging so that no fluid goes in or out of the lens and no glistenings will occur.

I use the ORA System (WaveTec Vision) intraoperatively during approximately 95% of my cataract surgical cases to ensure accuracy. The system only adds about 30 seconds to surgery time, improves my outcomes by more than 20%, and reduces the need for enhancements, so when I decided to try a new lens, I wanted to ensure I was hitting my refractive target at the very start.

I analyzed 50 cases (50 eyes) in an effort to optimize the a-constant for the glistening-free lens. My preoperative workup consisted of using the IOLMaster (Carl Zeiss Meditec) with several formulas, Atlas 9000 Corneal Topography System (Carl Zeiss Meditec), and a macular optical coherence tomography scan.

I began surgery after the patient had topical lidocaine PF gel. My surgical procedure began with a 1.8-mm clear-cornea, three-stepped incision. I performed coaxial micro-incisional cataract surgery) (MICS) and employed a divide and conquer technique for phacoemulsification. I repressurized the eye to 20 mm of mercury.

Then I performed intraoperative aberrometry in the aphakic state to acquire an IOL power, an astigmatic power, and the axis of astigmatism. I enlarged the wound to 2.5 mm for insertion of the glistening-free lens with the n100 inserter.

I then removed all viscoelastic as the lens slowly unfolded and again repressurized the eye to 20 mm mercury. I took a final ORA reading to reconfirm the IOL power or to evaluate any residual astigmatism left if LRI’s had been done.

Postoperatively, all of the data was entered in WaveTec’s AnalyzOR data bank so the refractive outcomes for these cases could be analyzed and the lens constant for this IOL model could be optimized. The AnalyzOR archives data through the optimization process, allows me to further refine my ORA IOL calculations.

In 12% of eyes my preoperative calculation was chosen instead of the ORA reading, in 34% of eyes ORA confirmed my choice, and in 54% of eyes ORA influenced my choice.

ORA reduces surgeons’ cataract enhancement rate two-fold, and five-fold on post-refractive patients. I have been using the system in my practice for the past 5 years. As the system has evolved my outcomes have continued to improve, decreasing my enhancement rate to almost nothing.

The success and accuracy of the system has allowed me to raise the bar for cataract outcomes to be even better than LASIK outcomes.

In this series, 100% of the cases with this model were within 0.50 D of ORA’s predicted postoperative outcome and 75% were within 0.25 D. The mean absolute prediction error in these cases was 0.17 ± 0.12. Ninety-nine percent of the UCVA were 20/40 or better and 99% BCVA were 20/20.

ORA provides consistent, reliable intraoperative guidance that enables surgeons to achieve improved patient outcomes and improve patient satisfaction. When educating my patients about the benefits of using the system, I explain to them that it allows me to make the prediction of their IOL more accurate, and it improves their surgical outcome, virtually eliminating the need of additional surgery.

If my target is to ensure that patients no longer have to wear glasses at distance or intermediate, ORA will assist me in achieving the targeted refraction for premium implants. If I did not have an intraoperative aberrometer like ORA, I would have to rely solely on three or four calculations based on preoperative measurements, and the risk of not achieving the desired postoperative outcome would be increased significantly.

In my practice ORA is invaluable, and I can’t imagine performing surgery without it. The technology has evolved greatly since the first-generation system was introduced, and its accuracy amazes me.

Now that the system has undergone another significant upgrade with the introduction of VerifEye, which provides critical feedback on eye stability, the bar will be raised even higher.

References

Tognetto D, Toto L, Sanguinetti G, Ravalico G. Glistenings in foldable intraocular lenses. J Cataract Refract Surg. 2002;28:1211-1216.

Moreno-Montanes J, Alvarez A, Rodriguez-Conde R, Fernandez-Hortelano A. Clinical factors related to the frequency and intensity of glistenings in AcrySof intraocular lenses. J Cataract Refract Surg. 2003; 29:1980-1984.

Behndig A, Mőnestam E. Quantification of glistenings in intraocular lenses using Scheimpflug photography. J Cataract Refract Surg. 2009;35:14-17.

P. Dee G. Stephenson, MD, FACS, is on the speakers’ bureau for Bausch + Lomb and WaveTec Vision and is a consultant to Aaren Scientific and WaveTec Visiom.