Validity of fluorexon disodium versus sodium fluorescein for use in Goldmann tonometry.
OBJECTIVE
To evaluate the safety, validity, and comfort of 0.35% fluorexon disodium and 0.4% benoxinate (Flura-Safe) compared with the gold standard of 0.25% sodium fluorescein and 0.4% benoxinate for Goldmann applanation tonometry (GAT).


METHODS
This was a double-masked, randomized, crossover clinical trial. Subjects received either the standard or study formulation for GAT on visit 1 and the other formulation 1 week later. At each visit, tonometer mire quality, adequacy of fluorescence, ease of intraocular pressure (IOP) measurements, the IOP value, and anesthetizing efficacy of the formulation were assessed. Subjects graded general comfort, soreness and irritation, and burning and stinging of each formulation at 1 and 5 minutes after drop instillation.


RESULTS
Sixty-seven subjects completed the study. The mean IOP was 13.9 +/- 2.7 with fluorexon and 13.9 +/- 2.8 mm Hg with fluorescein OD and 14.0 +/- 2.8 with fluorexon and 13.9 +/- 2.5 mm Hg with fluorescein OS. The measurements with the 2 formulations were highly correlated for OD and OS, and the differences between the 2 measurements were not clinically significant. There was also no significant difference between the 2 drops in mire clarity, adequacy of fluorescence, or corneal anesthesia. However, fluorexon was statistically more comfortable (P = 0.039) and caused less stinging and burning (P = 0.014) at 1 minute versus the fluorescein formulation.


CONCLUSIONS
Not only was the new fluorexon product accurate and effective in GAT, it was also statistically more comfortable and had a less stinging and burning effect at 1 minute after drop instillation than the traditional fluorescein formulation. Because fluorexon is less likely to stain soft contact lenses, this may be the dye-anesthetic formulation of choice for practices that routinely perform GAT.
Ng
Loretta T
LT
Southern California College of Optometry, Fullerton 92831, USA. lng@scco.edu
Tong
Judy W
JW
De Land
Paul N
PN
D000328:Adult; D003263:Contact Lenses, Hydrophilic; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D019793:Fluorescein / Q000008:administration & dosage* / Q000009:adverse effects; D005452:Fluoresceins / Q000008:administration & dosage* / Q000009:adverse effects; D005456:Fluorescent Dyes / Q000008:administration & dosage* / Q000009:adverse effects; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D014065:Tonometry, Ocular
D005452:Fluoresceins; D005456:Fluorescent Dyes; D019793:Fluorescein; C007740:fluorexon