OCULUS Pentacam Interpretation Manual page 127

17 Holladay Report & Holladay EKR65 Detail Report
Figure 157: Holladay Report of a normal exam
The upper left box in
Figure 157 shows the general patient data.
The center upper box in [31]
Figure 157 shows the Equivalent K-Readings 65 (EKR65) for the 4.5 mm
zone along with mean EKR65, astigmatism, Q-value (6 mm zone) and total spherical aberration (SA)
[Z(4,0) + Z(6,0) + Z(8,0) for 6.0 mm zone]. The EKR65 values in this have been shown to be optimal
values to use in IOL power calculations for K-readings including the amount of corneal astigmatism
using the Holladay IOL consultant software. The values include front and back surface power and
astigmatism, so no additional adjustments are necessary for the back surface in toric IOL calculations.
The total SA is the sum of the 4th, 6
and 8 order Zernike SA terms and is the best value to use
th th
in the selection of aspheric IOLs [32]. Examples of aspheric IOLs are the Tecnis (Advances Medical
Optics, Santa Ana, Calif.), with a total SA of 0.27 μm, the Acrysof SN60WF (Alcon Inc., Fort Worth,
Texas), which is nominally -0.18 μm and varies with IOL power, and the SofPort AO (Bausch & Lomb,
Rochester, New York), which is 0.00 μm [33]. An ocular (corneal + IOL) SA of zero will result in the
best visual performance at the target refraction (usually emmetropia). A small amount of residual
ocular SA will cause the same amount of blur, whether positive or negative. However, since the pupil
constricts in response to near (accommodative) stimuli, negative residual ocular SA results in better
near vision, so if there must be a residual SA, slightly negative is preferable.
The upper right box in Figure 157 shows the ratio of front to back radii (normal 82.2% ± 2.1%),
quality specification QS (i.e. the examination QS of the 3D scan), pupil diameter, pachymetry
minimum, estimated k mean before refractive surgery and estimated refractive change due to
refractive surgery.
125