Wednesday, November 2, 2011

Abstract: Meibum lipid composition in asians with DED

Meibum lipid composition in asians with dry eye disease.

Previous lipidomic analyses of the human meibum had largely focused on individuals from non-Asian populations, despite the higher prevalence of dysfunctional tear syndrome (DTS) observed across Asia. Information pertaining to the alterations in lipid profiles in relation to DTS onset and progression is also lacking and warrants comprehensive experimental analysis. METHODOLOGIES/

We examined the meibum lipidome of 27 DTS patients and 10 control subjects for a total of 256 lipid species from 12 major lipid classes, including cholesteryl ester (CE), wax ester (WE), triacylglyceride (TAG), (O-acyl)-ω-hydroxy fatty acid (OAHFA), glycerophospholipids (phosphatidylcholine, PC; phosphatidylethanolamine, PE; phosphatidylinositol, PI; phosphatidylglycerol, PG) and sphingolipids (sphingomyelin, SM; ceramide, Cer; glucosylceramide, GluCer; dihexosylceramide, DihexCer). Neutral lipids were analysed using high-performance liquid-chromatography coupled with mass spectrometry (HPLC/MS) and tandem mass spectrometry (MS/MS) was used for the qualitative and quantitative analysis of polar lipid species. DTS patients were classified into three severity groups (i.e. mild, moderate and severe) based on the ocular surface disease index (OSDI). A significantly lower level of TAG (p<0.05) was observed in patients under the moderate category compared to the mild category. Notably, a number of OAHFA species displayed consistently decreasing levels that correlate with increasing disease severity. An attempt was also made to investigate the changes in meibum lipid profiles of DTS patients compared to normal individuals classified based on OSDI score. Several unsaturated TAG and PC species were found at significantly higher levels (p<0.05) in patients than controls.

The current study presents, for the first time, a comprehensive lipidome of meibum from individuals of an Asian ethnicity, which can potentially offer new insights into the higher prevalence of DTS observed amongst Asian populations. This study also represents an attempt towards identification of lipid species in meibum which could serve as marker for DTS.

PLoS One. 2011;6(10):e24339. Epub 2011 Oct 17.
Lam SM, Tong L, Yong SS, Li B, Chaurasia SS, Shui G, Wenk MR.
Department of Biological Sciences, National University of Singapore, Singapore, Singapore.

Monday, October 31, 2011

Abstract: Once again, dry eye gets short shrift in LASIK studies

I guess I'm on the warpath this morning.

Refractive surgery research at its best.

This abstract...

1) Purports to assess dry eye amongst its outcome measures (after all, it's the #1 complication so they'd better pay it lip service)
2) Then it uses the most unreliable not to mention barbaric method to evaluate dry eye (Schirmer)
3) Then it doesn't tell us what the dry eye results were, because naturally, only vision matters.

Come on guys, surely you can do better than this.

A prospective, randomized, fellow eye comparison of WaveLight Allegretto Wave Eye-Q versus VISX CustomVue™ STAR S4 IR™ in laser in situ keratomileusis (LASIK): analysis of visual outcomes and higher order aberrations.

To compare outcomes in visual acuity, refractive error, higher-order aberrations (HOAs), contrast sensitivity, and dry eye in patients undergoing laser in situ keratomileusis (LASIK) using wavefront (WF) guided VISX CustomVue and WF optimized WaveLight Allegretto platforms.

In this randomized, prospective, single-masked, fellow eye study, LASIK was performed on 44 eyes (22 patients), with one eye randomized to WaveLight Allegretto, and the fellow eye receiving VISX CustomVue. Postoperative outcome measures at 3 months included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive error, root-mean-square (RMS) value of total and grouped HOAs, contrast sensitivity, and Schirmers testing.

Mean values for UDVA (logMAR) were -0.067 ± 0.087 and -0.073 ± 0.092 in the WF optimized and WF guided groups, respectively (P = 0.909). UDVA of 20/20 or better was achieved in 91% of eyes undergoing LASIK with both lasers while UDVA of 20/15 or better was achieved in 64% of eyes using the Allegretto platform, and 59% of eyes using VISX CustomVue (P = 1.000). In the WF optimized group, total HOA increased 4% (P = 0.012), coma increased 11% (P = 0.065), and spherical aberration increased 19% (P = 0.214), while trefoil decreased 5% (P = 0.490). In the WF guided group, total HOA RMS decreased 9% (P = 0.126), coma decreased 18% (P = 0.144), spherical aberration decreased 27% (P = 0.713) and trefoil decreased 19% (P = 0.660). One patient lost one line of CDVA secondary to residual irregular astigmatism.

Both the WaveLight Allegretto and the VISX CustomVue platforms had equal visual and safety outcomes. Most wavefront optimized HOA values trended upward, with a statistically significant increase in total HOA RMS. Eyes treated with the WF guided platform showed a decreasing trend in HOA values.

Clin Ophthalmol. 2011;5:1339-47. Epub 2011 Sep 20.
Moshirfar M, Betts BS, Churgin DS, Hsu M, Neuffer M, Sikder S, Church D, Mifflin MD.
John A Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA.

Abstract: Video TFBUT method versus classic method

This is an interesting discussion of ways to capture TBUT.

Measurement of ocular surface protection under natural blink conditions.

To evaluate a new method of measuring ocular exposure in the context of a natural blink pattern through analysis of the variables tear film breakup time (TFBUT), interblink interval (IBI), and tear film breakup area (BUA).

The traditional methodology (Forced-Stare [FS]) measures TFBUT and IBI separately. TFBUT is measured under forced-stare conditions by an examiner using a stopwatch, while IBI is measured as the subject watches television. The new methodology (video capture manual analysis [VCMA]) involves retrospective analysis of video data of fluorescein-stained eyes taken through a slit lamp while the subject watches television, and provides TFBUT and BUA for each IBI during the 1-minute video under natural blink conditions. The FS and VCMA methods were directly compared in the same set of dry-eye subjects. The VCMA method was evaluated for the ability to discriminate between dry-eye subjects and normal subjects. The VCMA method was further evaluated in the dry eye subjects for the ability to detect a treatment effect before, and 10 minutes after, bilateral instillation of an artificial tear solution.

Ten normal subjects and 17 dry-eye subjects were studied. In the dry-eye subjects, the two methods differed with respect to mean TFBUTs (5.82 seconds, FS; 3.98 seconds, VCMA; P = 0.002). The FS variables alone (TFBUT, IBI) were not able to successfully distinguish between the dry-eye and normal subjects, whereas the additional VCMA variables, both derived and observed (BUA, BUA/IBI, breakup rate), were able to successfully distinguish between the dry-eye and normal subjects in a statistically significant fashion. TFBUT (P = 0.034) and BUA/IBI (P = 0.001) were able to distinguish the treatment effect of artificial tears in dry-eye subjects.

The VCMA methodology provides a clinically relevant analysis of tear film stability measured in the context of a natural blink pattern.

Clin Ophthalmol. 2011;5:1349-57. Epub 2011 Sep 22.
Abelson R, Lane KJ, Angjeli E, Johnston P, Ousler G, Montgomery D.
Arizona State University, Tempe, AZ, USA.

A Monday morning rant on LASIK, ARSC and dry eye

The American Refractive Surgery Council Discusses How Advances in LASIK Open Door for Those Once Ineligible

DALLAS, TX -- (Marketwire) -- 10/28/11 -- LASIK was once off-limits to people with thin corneas, dry eye and prescriptions in higher ranges. But thanks to advances in technology and technique, many of those once ineligible for LASIK may now benefit from the popular vision correction procedure....


Classic propaganda on a Monday morning, before I've even had my first cup of coffee. Oops (slap) I forgot, back to green tea.

Fifteen plus years into LASIK, when we've had all this time to study what is well known to be its #1 long-term complication (dry eye), who gets it worst and why... you'd think we would acquire this knowledge and use it to narrow the candidate pool so as to exclude those at highest risk.

Nope. Been there, done that - after all, we kinda-sorta agreed years ago not to push symptomatic people with Sjogrens or RA into LASIK, and to offer PRK instead to a few other people that we think might be high risk, right? That oughta shut up the naysayers.

And we know people everywhere with dry eye are pining to get LASIK, and we want to serve the public well, right? So this is no time to be cautious! It's time to EXPAND the candidate pool. Those fancy new dry eye tests can all be used as part of a bold new marketing plan to show how much you care by identifying people with pre-existing dry eye , explaining how great your technology is at not inducing dry eye, and plying them with steroids and Restasis for awhile before surgery.

Viola. Dry eye? No problem. You Too can benefit from the delights of LASIK! After all, my fancy schmancy femtosecond laser is the latest and greatest and Studies Have Shown* that those don't create as much dry eye as microkeratomes.

Come on guys. You are so blooming predictable. LASIK revenues plummet in an economy like this, and everyone gets more aggressive with the marketing - at what cost?

*well okay maybe not this one.