Thursday, October 1, 2009

Abstract: Systane, Optive, and visual acuity

For your reading ease...

PEG/PG = Systane

CMC/glycerin = Optive

(at least I'm assuming so as those are the only products I know with the indicated active ingredients)


The effects of lubricant eye drops on visual function as measured by the Inter-blink interval Visual Acuity Decay test.
Clin Ophthalmol. 2009;3:501-6. Epub 2009 Sep 24.
Torkildsen G.
Andover Eye Associates, Andover, MA, USA.

OBJECTIVE: The purpose of the current study was to evaluate the effects of two marketed ocular lubricants on the visual decay in dry eye patients using the Inter-blink interval Visual Acuity Decay (IVAD) test.

METHODS: This controlled, randomized, double-masked crossover study compared the effects of a polyethylene glycol/propylene glycol-based (PEG/PG) tear and a carboxymethylcellulose sodium (CMC)/glycerin tear on the visual acuity decay between blinks of dry eye patients. At visit 1 (Day 0), baseline IVAD measurements were recorded prior to instillation of a single drop of randomized study medication. IVAD testing was repeated at 15-, 45-, and 90-minutes post-instillation. Reading rate and functional blink rate were also evaluated. At the second visit (Day 7 +/- 3), study procedures were repeated using crossover treatment.

RESULTS: Forty-eight (48) subjects with dry eye (61.1 +/- 14.8 years old, 79.2% female, 95.8% white) completed the study. Treatment with the PEG/PG-based tear demonstrated statistically significantly longer time to one-line loss of best-corrected visual acuity (BCVA) as determined by the IVAD test at 90 minutes post-instillation compared to the CMC/glycerin tear (P = 0.0365). Measurements of median time at BCVA, reading rate, and functional blink rate were similar for both treatments. Both formulations were well tolerated in the population studied.

CONCLUSIONS: Treatment with the PEG/PG-based tear demonstrated statistically significant improved maintenance of visual acuity between blinks at 90 minutes post-instillation compared to the CMC/glycerin tear. This is the first study to demonstrate the ability of an artificial tear to extend visual acuity maintenance between blinks, as measured by the IVAD test.

Monday, September 28, 2009

Drug update: Prolacria chances declining?

Wedbush Morgan Securities has downgraded Inspire in part because of analyst concerns over whether Prolacria is producing good enough clinical data to ever get approved.

UPDATE 1-RESEARCH ALERT-Wedbush cuts Inspire Pharma to neutral
9/23/2009, Forbes

...'That key early-stage data won't be released until medical conferences in 2010, suggest to us that management will take their time to evaluate the next steps and may even choose a back-up compound to test in early stage again,' analyst Liana Moussatos said.

Moussatos, who maintained her $15 fair value target, sees upcoming late-stage data on the company's experimental dry-eye treatment Prolacria as a 'high-risk catalyst' as the drug has had mixed data in the past.

'We give Prolacria a 30 percent or less likelihood of success,' she said in a note to clients.

Abstract: Improved tear meniscus measurements via OCT

Reproducibility of tear meniscus measurement by fourier-domain optical coherence tomography: a pilot study.
Ophthalmic Surg Lasers Imaging. 2009 Sep-Oct;40(5):442-7. doi: 10.3928/15428877-20090901-01.
Zhou S, Li Y, Lu AT, Liu P, Tang M, Yiu SC, Huang D.

BACKGROUND AND OBJECTIVE:To study the reproducibility of tear meniscus measurement with high-speed high-resolution Fourier-domain optical coherence tomography (FD-OCT).

PATIENTS AND METHODS:Twenty normal participants were enrolled in this prospective study. The lower tear meniscus in the right eye of each subject was imaged by vertical scans centered on the inferior cornea and the lower eyelid using an FD-OCT system (RTVue; Optovue, Inc., Fremont, CA) with a corneal adaptor. The system performs 26,000 axial scans per second and has a 5-micron axial resolution. Each subject was examined at two visits 30 to 60 days apart. Each eye was scanned twice on each visit. The scans were taken 2 seconds after a blink. The lower meniscus height, depth, and cornea-meniscus angle were measured with a computer caliper. The cross-sectional area was calculated using a two-triangle approximation.

RESULTS:The between-visits coefficient of variation was 17.5%, 18.0%, 35.5%, and 12.2% for meniscus height, depth, area, and angle, respectively. The intraclass correlations for these parameters were 0.605, 0.558, 0.567, and 0.367, respectively.

CONCLUSION:FD-OCT measures lower tear meniscus dimensions and area with higher between-visits reproducibility than previous OCT instruments. FD-OCT may be a useful way to measure dry eye severity and treatment effectiveness.