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1 Eye Clinic Day Hospital 2 Federal University of São Paulo - UNIFESP São Paulo - Brazil

Analysis of Ocular Wavefront Aberrations in Post Penetrating Keratoplasty Eyes with Two Different Hartmann-Shack Aberrometers. Adriana S. Forseto 1 , MD; Telma Pereira 2 , MD; Vera Mascaro 2 , MD; Lucila Pinto 1 , MD; Walton Nos é 1,2 , MD. 1 Eye Clinic Day Hospital

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1 Eye Clinic Day Hospital 2 Federal University of São Paulo - UNIFESP São Paulo - Brazil

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  1. Analysis of Ocular Wavefront Aberrations in Post Penetrating Keratoplasty Eyes with Two Different Hartmann-Shack Aberrometers Adriana S. Forseto1, MD; Telma Pereira2, MD; Vera Mascaro2, MD; Lucila Pinto1, MD; Walton Nosé1,2, MD 1Eye Clinic Day Hospital 2Federal University of São Paulo - UNIFESP São Paulo - Brazil The authors have no financial interest in the subject matter of this poster

  2. Introduction • Penetrating keratoplasty (PKP) is still widely performed as a treatment option for the correction of advanced keratoconus. However, visual rehabilitation is so far influenced by the presence of different degrees of refractive errors. • Several surgical refractive treatments have already been proposed. Unfortunately, the amount of total higher-order aberrations (HOA) present in these eyes is faraway that observed in non operated eyes. This may influence the visual quality experienced by these patients. • Many wavefront sensors have more difficulty of measuring the ocular aberrations on eyes with highly irregular corneas. Inaccuracies in wavefront measurements may compromise clinical testing and the refractive correction procedures. • Another concern is the presence of possible discrepancies between the wavefront-derived refractions and the clinical measurements, since many customized ablation platforms use these data to treat the refractive error.

  3. Purpose To analyze ocular order aberrations derived from Ladarwave (Alcon) and Zywave (Bausch & Lomb) devices in eyes after penetrating keratoplasty (PKP) for keratoconus (KC) and to compare the clinical refraction with the lower order aberrations obtained from these two aberrometers

  4. Inclusion criteria Minimum age: 18 yo History of PKP for KC Clear corneal graft Previous removal of all keratoplasties sutures Exclusion criteria Other ocular pathology than KC Other previous surgery than PKP Contact lens wear Methods • Thirty eyes were evaluated with 2 wavefront (WF) sensors: • Ladarwave and Zywave

  5. Methods • The WF refractions were evaluated for 3.50mm pupil and compared with the clinical measurements (manifest and cycloplegic), after conversion to power vectors coordinates: spherical equivalent (M or Sph Eq), J0 and J45 (astigmatism)(1) • The WF aberrations (up to the 4th order) were compared between the 2 devices (6.00mm pupil size) • Parametric testing was used with a significant level of p < 0.05 (1)Thibos LN, Wheeler W, Horner DG. Power vectors: an application of Fourier analysis to the description and statistical analysis of refractive error. Optom Vis Sci 1997;74:367-375.

  6. Results • The mean time between PKP and WF examinations was: • 5.95±4.37 years (range, 1 to 15 years) • The Zywave aberrometer was unable to capture the images in 3 eyes and the Ladarwave in one of them • Centroids view and processed image in post PKP eye • Note the irregularities at the periphery

  7. Results Correlation between the manifest and the Ladarwave and the Zywave derived refraction Both wavefront devices derived refractions were highly correlated to clinical manifest refraction

  8. Results Correlation between the cycloplegic and the Ladarwave and the Zywave derived refraction Both wavefront devices derived refractions were highly correlated to clinical cycloplegic refraction

  9. Results Analysis of variance with repeated measurements of the clinical and the wavefront sensors-derived refractions • Statistically significant differences (p < 0.05) were found between: • LADARWave Sph Eq and Zywave Sph Eq • LADARWave J0 and Zywave J0 • Zywave SphEq and the manifest Sph Eq • LADARWave Sph Eq and the cycloplegic Sph Eq

  10. Results Mean values of total HOA, 3rd and 4th HOA (6.00mm pupil) • No statistically significant discrepancies in higher-order aberrations (HOA) measurements between the two Hartmann-Shack devices were observed. • Trefoil aberrations were dominant when compared to coma or spherical aberrations in post-PKP eyes.

  11. Conclusions • Eyes with PK have a great amount of ocular aberrations • The correction of these aberrations may be limited by the discrepancies among the wavefront refractions and the clinical measurements, since these customized ablation platforms use their own data to treat the refractive error

  12. References • Chalita, M. R. and R. R. Krueger (2004). "Wavefront aberrations associated with the Ferrara intrastromal corneal ring in a keratoconic eye." J Refract Surg20(6): 823-30. • Jafri, B., X. Li, et al. (2007). "Higher order wavefront aberrations and topography in early and suspected keratoconus." J Refract Surg23(8): 774-81. • Maeda, N., T. Fujikado, et al. (2002). "Wavefront aberrations measured with Hartmann-Shack sensor in patients with keratoconus." Ophthalmology109(11): 1996-2003. • McLaren, J. W., S. V. Patel, et al. (2009). "Corneal wavefront errors 24 months after deep lamellar endothelial keratoplasty and penetrating keratoplasty." Am J Ophthalmol147(6): 959-65, 965 e1-2. • Okamoto, C., F. Okamoto, et al. (2008). "Higher-order wavefront aberration and letter-contrast sensitivity in keratoconus." Eye22(12): 1488-92. • Pantanelli, S., S. MacRae, et al. (2007). "Characterizing the wave aberration in eyes with keratoconus or penetrating keratoplasty using a high-dynamic range wavefront sensor." Ophthalmology114(11): 2013-21. • Pesudovs, K. and D. J. Coster (2006). "Penetrating keratoplasty for keratoconus: the nexus between corneal wavefront aberrations and visual performance." J Refract Surg22(9): 926-31. • Reinstein, D. Z., T. J. Archer, et al. (2009). "Combined corneal topography and corneal wavefront data in the treatment of corneal irregularity and refractive error in LASIK or PRK using the Carl Zeiss Meditec MEL 80 and CRS-Master." J Refract Surg25(6): 503-15. • Shah, S., S. Naroo, et al. (2003). "Nidek OPD-scan analysis of normal, keratoconic, and penetrating keratoplasty eyes." J Refract Surg19(2 Suppl): S255-9. • Smolek, M. K. and S. D. Klyce (2003). "Zernike polynomial fitting fails to represent all visually significant corneal aberrations." Invest Ophthalmol Vis Sci44(11): 4676-81. • Thibos, L. N. and D. Horner (2001). "Power vector analysis of the optical outcome of refractive surgery." J Cataract Refract Surg27: 80-85. • Vinciguerra, P., E. Albe, et al. (2009). "Refractive, topographic, tomographic, and aberrometric analysis of keratoconic eyes undergoing corneal cross-linking." Ophthalmology116(3): 369-78. • Yoon, G., S. Pantanelli, et al. (2008). "Comparison of Zernike and Fourier wavefront reconstruction algorithms in representing corneal aberration of normal and abnormal eyes." J Refract Surg24(6): 582-90.

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