Document Detail

Seven-year changes in corneal power and aberrations after PRK or LASIK.
MedLine Citation:
PMID:  22879417     Owner:  NLM     Status:  MEDLINE    
PURPOSE: To examine long-term changes in corneal power and aberrations in myopic patients randomized to photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK).
METHODS: Forty-five patients with myopia from -6 to -8 diopters (spherical equivalent refraction) were randomized to PRK (n = 20) or LASIK (n = 25). Patients were examined preoperatively and for up to 7 years after surgery. Measurements included refraction, topography (TMS-1), and ultrasound pachymetry. By 3 years, 16 PRK and 15 LASIK patients were examined and by 7 years, 9 PRK and 7 LASIK subjects were available. Only patients who had not been reoperated and attended the two late controls were included in data analyses. Optical analysis of topographic data was used to calculate corneal power and wavefront aberrations.
RESULTS: PRK and LASIK caused a similar reduction in corneal power. During the first year after PRK, corneal power increased, but remained stable from 1 to 7 years. In contrast, corneal power continued to increase from 1 to 7 years after LASIK. Both PRK and LASIK caused an increase in coma-like and spherical aberrations that remained constant for 7 years. No significant changes in other higher-order aberrations were observed.
CONCLUSIONS: The cornea may not be stable even 7 years after LASIK, as indicated by the continuing increase in corneal power. In contrast, PRK appears stable from 1 year post surgery. Coma-like and spherical aberrations are permanently increased after PRK and LASIK. ( number, NCT00404105.).
Anders Ivarsen; Jesper Hjortdal
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Publication Detail:
Type:  Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't     Date:  2012-09-06
Journal Detail:
Title:  Investigative ophthalmology & visual science     Volume:  53     ISSN:  1552-5783     ISO Abbreviation:  Invest. Ophthalmol. Vis. Sci.     Publication Date:  2012 Sep 
Date Detail:
Created Date:  2012-09-07     Completed Date:  2012-12-03     Revised Date:  2013-01-09    
Medline Journal Info:
Nlm Unique ID:  7703701     Medline TA:  Invest Ophthalmol Vis Sci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  6011-6     Citation Subset:  IM    
Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark.
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MeSH Terms
Cornea / physiopathology*
Corneal Pachymetry
Corneal Topography
Corneal Wavefront Aberration / physiopathology*
Follow-Up Studies
Keratomileusis, Laser In Situ*
Lasers, Excimer / therapeutic use*
Middle Aged
Myopia / physiopathology,  surgery*
Photorefractive Keratectomy*
Refraction, Ocular / physiology
Time Factors
Visual Acuity / physiology
Young Adult

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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