Astigmatism Research Today is a free monthly online journal that collates and summarizes the latest research about Astigmatism, including details on cornea, retina, treatment, types, signs, tests.

Long-term follow-up of orthokeratology corneal reshaping using wavefront aberrometry and contrast sensitivity.

Stillitano I, Schor P, Lipener C, Hofling-Lima AL

Contact Lens and Refractive Surgery Sectors, Department of Ophthalmology, Paulista School of Medicine UNIFESP/EPM, Federal University of São Paulo, São Paulo, Brazil. ianestillitano@oftalmo.epm.br

PURPOSE: To evaluate changes in ocular wavefront aberrations and contrast sensitivity during 1-year follow-up of overnight orthokeratology. METHODS: Prospective study of 26 eyes that underwent orthokeratology with the BE lens design. Wavefront measurements were analyzed at baseline and after 1, 8, 30, 90, 180, and 365 nights of orthokeratology for a 6.5-mm pupil diameter. Contrast sensitivity 1 year after orthokeratology was compared to the baseline value under photopic conditions and mesopic conditions, with and without glare, in the spatial frequencies of 1.5, 3, 6, 12, and 18 cycles/degree. A P value of less than 0.05 was statistically significant. RESULTS: Higher-order aberration root-mean-square (HOA-RMS) increased statistically significantly from 0.41 +/- 0.12 microm to 1.04 +/- 0.32 microm up to night 8. Defocus (Z4) decreased until night 8 and then stabilized. Astigmatism (Z3 + Z5) did not change. There was a sevenfold increase in spherical aberration (Z12) until night 8, which subsequently remained unchanged (P<0.001). Coma (Z7 + Z8) increased until night 90 and then stabilized (P<0.001). Other Zernike modes showed stability at night 1, with the exception of quadrafoil (Z14) (P=0.048). Mesopic contrast sensitivity, with and without glare, at 18 cycles/degree, decreased but failed to reach statistical significance (P=0.922 and P=0.827, respectively). CONCLUSIONS: Most optical aberrations stabilized within the first week after beginning orthokeratology with BE lens. There was not a statistically significant reduction in contrast sensitivity 1 year after treatment.

Published 8 May 2008 in Eye Contact Lens, 34(3): 140-5.
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