Prevention of bacterial colonization of contact lenses with covalently attached selenium and effects on the rabbit cornea.
OBJECTIVE
Although silicone hydrogel materials have produced many corneal health benefits to patients wearing contact lenses, bacteria that cause acute red eye or corneal ulcers are still a concern. A coating that inhibits bacterial colonization while not adversely affecting the cornea should improve the safety of contact lens wear. A covalent selenium (Se) coating on contact lenses was evaluated for safety using rabbits and prevention of bacterial colonization of the contact lenses in vitro.


METHODS
Contact lenses coated with Se were worn on an extended-wear schedule for up to 2 months by 10 New Zealand White rabbits. Corneal health was evaluated with slit-lamp biomicroscopy, pachymetry, electron microscopy, and histology. Lenses worn by the rabbits were analyzed for protein and lipid deposits. In addition, the ability of Se to block bacterial colonization was tested in vitro by incubating lenses in a Pseudomonas aeruginosa broth followed by scanning electron microscopy of the contact lens surface.


RESULTS
The covalent Se coating decreased bacterial colonization in vitro while not adversely affecting the corneal health of rabbits in vivo. The Se coating produced no noticeable negative effects as observed with slit-lamp biomicroscopy, pachymetry, electron microscopy, and histology. The Se coating did not affect protein or lipid deposition on the contact lenses.


CONCLUSIONS
The data from this pilot study suggest that a Se coating on contact lenses might reduce acute red eye and bacterial ulceration because of an inhibition of bacterial colonization. In addition, our safety tests suggest that this positive effect can be produced without an adverse effect on corneal health.
Mathews
Steven M
SM
Department of Ophthalmology and Visual Sciences, Texas Tech University Health Science Center, Lubbock, TX 79430, USA. steven.mathews@ttuhsc.edu
Spallholz
Julian E
JE
Grimson
Mark J
MJ
Dubielzig
Richard R
RR
Gray
Tracy
T
Reid
Ted W
TW
D000818:Animals; D020099:Coated Materials, Biocompatible; D015169:Colony Count, Microbial; D003262:Contact Lenses, Extended-Wear / Q000382:microbiology*; D003315:Cornea / Q000187:drug effects* / Q000382:microbiology / Q000648:ultrastructure; D004195:Disease Models, Animal; D015818:Eye Infections, Bacterial / Q000382:microbiology / Q000473:pathology / Q000517:prevention & control*; D005500:Follow-Up Studies; D007634:Keratitis / Q000382:microbiology / Q000473:pathology / Q000517:prevention & control*; D008855:Microscopy, Electron, Scanning; D011552:Pseudomonas Infections / Q000382:microbiology / Q000473:pathology / Q000517:prevention & control*; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000302:isolation & purification*; D011817:Rabbits; D012643:Selenium / Q000494:pharmacology*
D020099:Coated Materials, Biocompatible; D012643:Selenium