Pupillengröße und Durchmesser der optischen Zone

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Dr. med. Ron Lehnert
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Registriert: 18.03.2004, 12:50
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Pupillengröße und Durchmesser der optischen Zone

Beitrag von Dr. med. Ron Lehnert » 17.08.2007, 18:58

1: J Cataract Refract Surg. 2005 Dec;31(12):2272-80.

Influence of pupil and optical zone diameter on higher-order aberrations after
wavefront-guided myopic LASIK.

Bühren J, Kühne C, Kohnen T.

Department of Ophthalmology, Johann Wolfgang Goethe-University, Frankfurt am
Main, Germany.

PURPOSE: To investigate the influence of pupil and optical zone (OZ) diameter on
higher-order aberrations (HOAs) after myopic wavefront-guided laser in situ
keratomileusis (LASIK). METHODS: Twenty-seven myopic eyes of 19 patients were
included. The mean preoperative spherical equivalent was -6.86 diopters (D) +/-
1.24 (SD) (range -4.25 to -9.5 D); the mean planned OZ diameter was 6.26 +/- 0.45
mm (range 5.7 to 7.1 mm). All patients had uneventful wavefront-guided LASIK
(Zyoptix version 3.1, Bausch & Lomb) and an uncomplicated follow-up of 12 months.
Wavefront measurements were performed with a Hartmann-Shack sensor in maximum
mydriasis preoperatively and 12 months after LASIK. Wavefront errors were
computed for pupil diameters (PDs) of 3.0, 3.5, 4.0, 5.0, 6.0, and 7.0 mm for the
individual OZ diameter and for the individual mydriatic PD (7.93 +/- 0.46 mm).
The impact of the relationship between pupil diameter and OZ diameter (fractional
clearance [FC]) on HOA was described and quantified using curvilinear regression
with a 4th-order polynomial fit. RESULTS: There was a reproducible relationship
between FC and the amount of induced HOA. The change in HOA root mean square and
primary spherical aberration (Z(4)0) was significantly correlated with FC. If the
OZ was 16.5% larger than the pupil (FC = 1.17), only half the amount of HOA was
expected to be induced than if the OZ equaled the pupil. In contrast, an OZ that
was 9% smaller than the pupil (FC = 0.91) resulted in an HOA induction 50% higher
than at FC = 1. CONCLUSION: The OZ zone to pupil ratio (fractional clearance) had
a significant impact on HOA induction after wavefront-guided LASIK.

PMID: 16473217 [PubMed - indexed for MEDLINE]
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