Accuracy of IOL Power Calculation Using Intraoperative Aberrometry System Compared With Holladay 2 Formula

Tuesday, April 29, 2014: 10:01 AM
Room 151B (Boston Convention and Exhibition Center)
Nausheen Abbas, MD, Albany Medical College, Slingerlands, NY, USA
Mala Krishnamoorthy, BS, Albany Medical College, Albany, NY, USA
Robert L. Schultze, MD, Albany Medical College, Delmar, NY, USA

Narrative Responses:

Purpose
To evaluate the predictability of intraocular lens (IOL) power calculation using the Optiwave Refractive Analysis (ORA) compared with the Holladay 2 formula in order to optimize cataract surgery refractive outcomes.

Methods
In a retrospective chart review, 53 eyes met inclusion criteria.  Eyes with complicated cataract surgery and visual comorbidity limiting final visual acuity (<20/30) were excluded.  Data collected included type of intraocular lens implanted, prior refractive surgery, post-operative refraction and predicted results of the ORA and Holladay 2 for the implant chosen. The data was stratified into 4 recipient subgroups (post-refractive, ReSTOR, monofocal, and toric).  The main outcome measure was the absolute error, in diopters (D), between the predicated refractive goal of each formula and the measured spherical equivalent at the 1-month postoperative visit.

Results
The mean absolute error (MAE) was calculated for each formula and compared and analyzed using the paired t-test.  Overall, the MAE was smaller with the ORA (0.30D) compared with the Holladay 2 (0.44D) (p=0.004, n=53).  When broken down by subgroup, the MAE in the post-refractive, ReSTOR, monofocal and toric groups was 0.26D vs. 0.69D (p=0.002, n=13); 0.26D vs. 0.33D (p=0.146, n=24); 0.44D vs. 0.55D (p=0.088, n=3); and 0.40D vs. 0.39D (p=0.889, n=13), for the ORA and Holladay 2 respectively.

Conclusion
Overall the IOL power calculation using ORA was shown to be more precise than with Holladay 2. Only the post-refractive subgroup demonstrated statistically significant superiority of the ORA IOL power prediction.  This data suggests that the ORA could serve as useful adjunctive method for calculating IOL power in post-refractive patients.