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Zvi A. Kresch, Lee Wiley, Anthony Realini; Measuring Post-Surgical Keratometry in Penetrating Keratoplasty Patients. Invest. Ophthalmol. Vis. Sci. 2012;53(14):121.
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There is an ongoing debate whether in patients with concurrent corneal and lenticular disease, it is better to proceed with a ‘triple’ procedure (penetrating keratoplasty (PK) + cataract extraction (CE) + intraocular lens (IOL) implantation) vs sequential surgeries (PK followed by CE and IOL implantation). This research project investigates the role of improved keratometric measuring devices to measure post-op corneal transplant keratometry (K) to improve IOL selection for future CE+IOL candidates.
Studied a cohort of patients who have undergone both PK and cataract surgery. Determined the final post-op spherical equivalent (SE). Based on post-op SE, determined what IOL would have produced SE of zero. This is the lens that should have been used to get to zero: the ideal IOL. Obtained keratometry readings on post-PK corneas using three different devices: Galelei simulated keratometry, Galelei total keratometry and IOL Master Keratometry. Determined what IOL to use, based on each of these Ks, to aim at SE of zero. Finally, used regression analysis to assess the relationship between model keratometry IOLs and ideal IOL.
Obtained data on 12 patients (3 male, 9 female). Average age was 59.7 years (range 44-77). Surgeries were performed between 1999 and 2010. Final BCVA was 20/70 or better. SE ranged from -3.75 to +2.25. Average Simulated K was 44.73 (41.15-47.95). Average Total K was 43.12 (38.94-45.84). Average IOL Master K was 45.37 (range 42.51-47.51). Regression analysis of each of the keratometric devices show a linear relationship with a r^2 (best fit) ranging from 81-85%. The slope of each relationship is equal showing that all three Ks have the same relationship with ideal IOL offset by the intercept which are explained by differences in keratometry techniques.
Based on results if you stage the surgical procedures (PK followed by CE+IOL), the postop Ks can help significantly in minimizing postop SE. Each of the three model Ks produced regression equations that predicted the ideal IOL. This suggests that optimal optical results are best obtained with staged procedures. Although this was a small sample size, the linear fits were very tight for all three model Ks. Future direction: a series of staged procedures with IOL selected based on post-op PK Ks to see if this predictive model holds up in prospective evaluation.
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