Ocular functional optical zone following hyperopic LASIK/PRK: Analysis based on polychromatic retinal image quality Mitchell P. Weikert, MD Li Wang, MD, PhD Douglas D. Koch, MD Cullen Eye Institute Baylor College of Medicine Houston, TX Financial disclosure: none.

Background Traditionally, the functional optical zone (FOZ) is analyzed based on corneal topography* Wavefront-guided treatments correct ocular aberrations on anterior cornea Optical quality of the anterior corneal surface may not represent retinal image quality of the whole eye  Due to the effect of the internal optics * Holladay & Janes. JCRS 2002; Boxer Wachler et al. JCRS 2002; Racine, Wang & Koch. AJO 2006; Tabernero et al. IOVS 2007

Purpose To investigate the size of the ocular FOZ before and after wavefront-guided hyperopic LASIK/PRK  Based on optical image quality of the whole eye

Patients and Methods Consecutive cases who underwent AMO- CustomVue LASIK or PRK (CV- LASIK/PRK) for Hyperopia by one surgeon between 1/1/05 to 6/1/09 Inclusion criteria:  Available follow-up at 6 months post-op  CustomVue wavefront measurements ≥6 mm at both pre-op and 6 months post-op

Patients 30 eyes of 21 subjects included  Age: 51 ± 8.4 years (31to 66 years)  Pre-op CV SE: ± 0.82 D (+0.20 to +3.53D)  Post-op CV SE: ± 0.63 D (-0.53 to +2.10D)  Refractive correction: ± 0.57 D ( to D)

Methods Based on CustomVue wavefront measurements, ocular wavefront aberrations were calculated for simulated pupils from 2–6 mm in 0.1 mm intervals Assuming full correction of 2 nd order aberrations, optical image quality of higher-order aberrations (HOAs, 3 rd -6 th order) was evaluated

Methods Using ZernikeTool program (AMO), polychromatic modulation transfer function (MTF) at 9 cyc/deg with Stiles-Crawford effect calculated for 2-6 mm pupils FOZ defined as the size over which the MTF at 9 cyc/deg was ≥0.18  MTF ≥ 0.18 maintains visual acuity of ≥ 20/20   Tabernero J, Klyce SD, Sarver EJ, Artal P. IOVS 2007

Results: FOZ FOZ range: pre-op: mm post-op: mm ≥ 6≥ 5≥ 4≥ 3 FOZ (mm) % of eyes Preop Postop

FOZ Change Following Myopic CV-PRK Δ in FOZ (mm)% of eyes  0.6 –  0.1 –  0.1 –  0.6 –  1.1 –  1.6 – 2.0 3

FOZ vs. 4 th -Order Spherical Aberration (SA) Post-op FOZ  with  spherical aberration (r 2 = 0.33, P<0.001 )

FOZ vs. Higher Order Aberrations (HOAs) Post-op FOZ  with  HOAs (r 2 = 0.31, P<0.001 )

Change in FOZ vs. Change in SA FOZ  with  SA (r 2 = -0.31, P<0.001 )

Change in FOZ vs. Change in HOAs FOZ  with  HOAs (r 2 = 0.36, P<0.001 )

Change in FOZ vs. refractive correction FOZ stable with  refractive correction (r 2 = 0.01, P<0.001 )

Summary 26% of eyes had post-op FOZ < 6 mm 74% of eyes had post-op FOZ ≥ 6 mm Post-op FOZ positively correlated with  SA and negatively correlated with  HOAs Hyperopic FOZ:   with  SA   with  HOAs  No change with  amount of refractive correction

Limitations Results are not correlated with measures of visual function Analysis only done up to 6-mm zone

Conclusion FOZ following wavefront-guided hyperopic LASIK/PRK:  Increased to area > 6 mm in 17% of eyes  Decreased to area < 6 mm in 20% of eyes These results may lead to further refinement of treatment parameters Study investigating optical FOZ following myopic LASIK/PRK presented as additional poster.