| Glenn - USAEyes.org 2006-01-09, 1:02 am |
| The poster has now been published.
~~~~~~~~~~~~~~~~~~
AJO; Volume 140, Issue 6, Pages 1059-1064.e1 (December 2005)
Recovery of Corneal Subbasal Nerve Density After PRK and LASIK
Presented in part at the European Society of Cataract and Refractive
Surgery, Paris, France, September 18-22, 2004, and at the Association
for Research in Vision and Ophthalmology, Ft Lauderdale, Florida, May
1-5, 2005.
Jay C. Erie, MDa , Jay W. McLaren, PhDa, David O. Hodge, MSb,
William M. Bourne, MD
Purpose
To measure and compare the return of corneal innervation up to 5 years
after photorefractive keratectomy (PRK) and laser in situ
keratomileusis (LASIK).
Design
Prospective, nonrandomized clinical trial.
Methods
Eighteen eyes of 12 patients received PRK to correct a mean refractive
error of -3.73 ± 1.30 diopters, and 16 eyes of 11 patients received
LASIK to correct a mean refractive error of -6.56 ± 2.44 diopters.
Corneas were examined by confocal microscopy before and at 1, 2, 3,
and 5 years after the procedures. Subbasal nerve fiber bundles were
measured to determine density (visible length of nerve/frame area) and
expressed as micrometers per square millimeters. Differences were
compared by Friedman's test and adjusted for multiple comparisons by
the Student-Newman-Keuls procedure.
Results
After PRK, mean subbasal nerve density was reduced by 59% at 1 year
(2764 ± 1321 m/mm2 [±SD]) when compared with preoperative (6786 ± 1948
m/mm2; P < .001). By 2 years, subbasal nerve density (6242 ± 1763
m/mm2) was not significantly different from density before PRK and
remained unchanged to 5 years (5903 ± 3086 m/mm2). After LASIK,
subbasal nerve density was reduced by 51%, 35%, and 34% at 1, 2, and 3
years, respectively (P < .001). By 5 years, subbasal nerves had
returned to densities (4441 ± 2819 m/mm2) that were not significantly
different from densities before LASIK (5589 ± 2436 m/mm2).
Conclusion
Corneal subbasal nerve density does not recover to near preoperative
densities until 5 years after LASIK, as compared with 2 years after
PRK.
Glenn Hagele
Executive Director
USAEyes.org
"Consider and Choose With Confidence"
Email to glenn dot hagele at usaeyes dot org
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I am not a doctor.
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