Mark Speaker, M.D., Ph.D. Coauthors Cataract Surgery & Lens Implant Calculation After Hyperopic Refractive Surgery Study

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 and Yu published the results of their study ” Intraocular Lens Calculation After Hyperopic Refractive Surgery” in the journal, Ophthalmology, November 2007.

Abstract of Study and Publication

PURPOSE: To evaluate the effect of hyperopic refractive surgery on intraocular lens (IOL) power calculation, compare published methods of IOL power calculation after refractive surgery, evaluate the effect of prerefractive surgery refractive error on IOL deviation, and introduce a new alternative formula for IOL calculation in patients who have had refractive surgery for hyperopia.

DESIGN: Retrospective noncomparative case series.

PARTICIPANTS: Twenty eyes from 13 patients who had undergone cataract surgery after previous hyperopic refractive surgery.

METHODS: Seven different methods of IOL calculation were performed retrospectively: clinical history (IOL(hisK)), clinical history method at spectacle plane (IOL(hisKs)), vertex (IOL(vertex)), back calculated (IOL(BC)), calculation based on average keratometry (IOL(avgK)), calculation based on steepest keratometry (IOL(steepK)), and calculation based on the double K formula (IOL(doubleK)). Each method's result was compared with an exact IOL (IOL(exact)), which would have resulted in emmetropia. Each method was then compared with change in spherical equivalent induced by refractive surgery (SE(h)). A paired t test was used to determine statistical significance.

MAIN OUTCOME MEASURE: Mean error in IOL power prediction for each method when compared to IOL(exact). RESULTS: When evaluating different methods of IOL calculations, IOL(vertex) was the most accurate, with a mean deviation from emmetropia of 0.42+/-1.75 diopters (D), followed by IOL(BC) (+0.54+/-1.86 D), IOL(hisK) (+1.56+/-2.35 D), IOL(hisKs) (+1.57+/-2.35 D), IOL(steepK) (+1.59+/-2.25 D), IOL(doubleK) (+1.65+/-2.56 D), and IOL(avgK) (+2.24+/-2.46 D). There was no statistical difference between IOL(vertex), IOL(BC), and IOL(exact). The power of IOL(avgK) would be inaccurate by 0.27x+1.53, where x = SE(h). Thus, most patients without the adjustment to IOL(avgK) would be left myopic. However, when IOL(avgK) is adjusted with this formula, there is no statistical difference to IOL(exact).

CONCLUSION: For IOL power selection in previously hyperopic patients, a predictive formula based only on SE(h) and current average keratometry readings was not found to statistically differ from IOL(exact). The IOL(vertex) and IOL(BC), which also did not statistically differ from IOL(exact), require prerefractive 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.