Risk factors for corneal infiltrative events during continuous wear of silicone hydrogel contact lenses.
OBJECTIVE
This study determined which microbiologic, clinical, demographic, and behavioral factors are associated with corneal infiltrative events (CIEs) during continuous wear of silicone hydrogel (SH) contact lenses.


METHODS
Subjects (n = 205) were fitted with lotrafilcon A lenses for continuous wear and observed for 1 year. The main exposures of interest were corneal staining and bacterial lens contamination. Kaplan-Meier (KM) plots were used to estimate the cumulative unadjusted probability of remaining CIE free, and Cox proportional hazards regression was used to model the hazard of having a CIE, as a function of key predictor variables.


RESULTS
The KM-unadjusted cumulative probability of remaining CIE free was 73.3%. Approximately 53% of subjects had repeated episodes of corneal staining (mild or greater), and 11.3% had repeated episodes of moderate or greater corneal staining. Corneal staining was not associated with the development of a CIE. The frequency of substantial bacterial bioburden on worn lenses at the time of a CIE was 64.7%, compared with only 12.2% during uncomplicated wear. The presence of substantial lens bacterial bioburden was associated with the development of a CIE (adjusted hazards ratio [HR], 8.66; 95% confidence interval [CI], 2.88-26.01). Smoking was also associated with a CIE (adjusted HR, 4.13; 95% CI, 1.27-13.45).


CONCLUSIONS
Corneal staining is common during continuous wear of SH lenses, but it is not associated with the development of a CIE. Smoking and substantial lens bacterial bioburden pose prominent risks of a CIE. In this study, more than 70% of the total risk of CIE in those with substantial lens bioburden is attributable to this exposure. (ClinicalTrials.gov number, NCT00727402).
Szczotka-Flynn
Loretta
L
Department of Ophthalmology and Visual Sciences, Case Western Reserve University and University Hospitals Eye Institute, Cleveland, Ohio 44106, USA. loretta.szczotka@uhhospitals.org
Lass
Jonathan H
JH
Sethi
Ajay
A
Debanne
Sara
S
Benetz
Beth Ann
BA
Albright
Matthew
M
Gillespie
Beth
B
Kuo
Jana
J
Jacobs
Michael R
MR
Rimm
Alfred
A
D000293:Adolescent; D000328:Adult; D001419:Bacteria / Q000302:isolation & purification* / Q000378:metabolism; D001422:Bacterial Adhesion / Q000502:physiology*; D003263:Contact Lenses, Hydrophilic / Q000382:microbiology*; D003320:Corneal Ulcer / Q000175:diagnosis / Q000382:microbiology*; D005260:Female; D015590:Fluorophotometry; D005500:Follow-Up Studies; D006801:Humans; D020100:Hydrogels; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011336:Probability; D011446:Prospective Studies; D012307:Risk Factors; D012828:Silicones; D013234:Stem Cells; D055815:Young Adult; D005466:Fluorocarbons
D020100:Hydrogels; D012828:Silicones; C481129:lotrafilcon A; D005466:Fluorocarbons