Mark Speaker, M.D., Ph.D. Coauthors Intraocular Lens Calculations After Refractive Surgery Article

Mark Speaker, M.D., Ph.D. is a Corneal Specialist and LASIK Surgeon in New York at Laser and Corneal Surgery Associates in Manhattan. He is widely recognized for his contributions to the fields of corneal and refractive surgery including LASIK and Corneal Transplantation through his efforts in patient care, research and ongoing physician education. Dr. Speaker, along with coauthors Drs. Chokshi, Latkany, Abramson, Soloway and Yu published the results of their study ” Intraocular Lens Calculations After Refractive Surgery” in the March 2005 Journal of Cataract and Refractive Surgery.

Abstract of Study and Publication

PURPOSE: To evaluate the effect of refractive surgery on intraocular lens (IOL) power calculation, compare methods of IOL power calculation after refractive surgery, evaluate the effect of pre-refractive surgery refractive error on IOL deviation, review the literature on determining IOL power after refractive surgery, and introduce a formula for IOL calculation for use after refractive surgery for myopia.

SETTING: Laser & Corneal Surgery Associates and Center for Ocular Tear Film Disorders, New York, New York, USA.

METHODS: This retrospective noncomparative case series comprised 21 patients who had uneventful cataract extraction and IOL implantation after previous uneventful myopic refractive surgery. Six methods of IOL calculation were used: clinical history (IOL(HisK)), clinical history at the spectacle plane (IOL(HisKs)), vertex (IOL(vertex)), back-calculated (IOL(BC)), calculation based on average keratometry (IOL(avgK)), and calculation based on flattest keratometry (IOL(flatK)). Each method result was compared to an "exact" IOL (IOL(exact)) that would have resulted in emmetropia and then compared to the pre-refractive surgery manifest refraction using linear regression. The paired t test was used to determine statistical significance.

RESULTS: The IOL(HisKs) was the most accurate method for IOL calculations, with a mean deviation from emmetropia of -0.56 diopter +/-1.59 (D), followed by the IOL(BC) (+1.06 +/- 1.51 D), IOL(vertex) (+1.51 +/- 1.95 D), IOL(flatK) (-1.72 +/- 2.19 D), IOL(HisK) (-1.76 +/- 1.76 D), and IOL(avgK) (-2.32 +/- 2.36 D). There was no statistical difference between IOL(HisKs) and IOL(exact) in myopic eyes. The power of IOL(flatK) would be inaccurate by -(0.47x+0.85), where x is the pre-refractive surgery myopic SE (SEQ(m)). Thus, without adjusting IOL(flatK), most patients would be left hyperopic. However, when IOL(flatK) is adjusted with this formula, it would not be statistically different from IOL(exact).

CONCLUSIONS: For IOL power selection in previously myopic patients, a predictive formula to calculate IOL power based only on the pre-refractive surgery SEQ(m) and current flattest keratometry readings was not statistically different from IOL(exact). The IOL(HisKs), which was also not statistically different from IOL(exact), requires pre-refractive surgery keratometry readings that are often not available to the cataract surgeon.

About Mark Speaker, M.D., Ph.D.

Mark Speaker, M.D. received his Doctor of Medicine (M.D.) and Doctor of Philosophy (Ph.D.) degrees from the Albert Einstein College of Medicine and completed his residency in Ophthalmology at The New York Eye and Ear Infirmary in Manhattan where he served as the Chief Resident. In addition he completed a Fellowship in Corneal and Refractive Surgery at Wills Eye Hospital in Philadelphia. He has served as the Director of the Cornea Service and Director of the Ophthalmology Residency Program at The New York Eye and Ear Infirmary. He has served on the Board of Directors of the Cornea Society, the Program Committee of the American Academy of Ophthalmology, and has received the Honor Award from the American Academy of Ophthalmology. He is currently Medical Director of TLC Laser Eye Centers Manhattan. In addition, he is the author of numerous articles and publications in the areas of Corneal Disease, Cornea Transplants, LASIK and Ocular Surface Disease including Dry Eyes and Dry Eye Syndrome.