Corneal sensitivity and burning sensation. Comparing topical ketorolac and diclofenac.
OBJECTIVE
To compare the effect of topical 0.5% ketorolac tromethamine and 0.1% diclofenac sodium on human corneal sensitivity and to assess the intensity of burning sensation at specific intervals after drop instillation.


METHODS
Double-masked parallel clinical study.


METHODS
Eleven women and 4 men (8 white, 4 Hispanic, 3 Asian), 22 to 60 years of age (mean [ +/- SD], 34 +/- 10 years).


METHODS
Repeated instillation of either ketorolac and placebo or diclofenac and placebo at 5-minute intervals.


METHODS
Assessment of corneal sensitivity before instillation, immediately after instillation, and after termination of drop application; and subjective evaluation of burning sensation by asking participants to rate burning on a scale ranging from 0 (none) to 3 (severe) after each drop application.


RESULTS
Both diclofenac (P < .01) and ketorolac (P < .01) decreased corneal sensitivity significantly, while the placebo had no measurable effect. After administration of additional drops over time, the effect of diclofenac and ketorolac increased. After termination of the drug instillation, corneal sensitivity returned to baseline significantly slower (P < .01) in participants receiving diclofenac than in those receiving ketorolac. Ketorolac (P = .01) and diclofenac (P < .05) were significantly more effective in whites than in nonwhites. Mean burning sensation was mild, and there was no statistically significant difference between the 2 drugs on this measure (P = .12).


CONCLUSIONS
The decrease in corneal sensitivity in normal human corneas is more pronounced and longer lasting with diclofenac than with ketorolac. Both drugs are well tolerated topically and may be useful for pain reduction after refractive corneal surgery.
Seitz
B
B
Doheny Eye Institute, University of Southern California School of Medicine, Los Angeles, USA.
Sorken
K
K
LaBree
L D
LD
Garbus
J J
JJ
McDonnell
P J
PJ
D000287:Administration, Topical; D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000009:adverse effects*; D002057:Burns, Chemical / Q000209:etiology* / Q000503:physiopathology; D003315:Cornea / Q000187:drug effects* / Q000502:physiology; D004008:Diclofenac / Q000008:administration & dosage / Q000009:adverse effects*; D004311:Double-Blind Method; D005126:Eye Burns / Q000139:chemically induced*; D005260:Female; D006801:Humans; D020911:Ketorolac Tromethamine; D008297:Male; D008875:Middle Aged; D009883:Ophthalmic Solutions; D012677:Sensation / Q000187:drug effects*; D014046:Tolmetin / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives*
D000894:Anti-Inflammatory Agents, Non-Steroidal; D009883:Ophthalmic Solutions; D004008:Diclofenac; D020911:Ketorolac Tromethamine; D014046:Tolmetin