Thursday, February 10, 2011

Abstract: Fresh dry eye after LASIK flap-lift retreatment

I have to confess I usually ignore the refractive journals & studies because they bother me. Doesn't matter anyway because, ironically enough, they rarely mention dry eye except in passing. But this one caught my eye. 8.3% of people who didn't get dry eye the first time got it in the retreatment. ... Though that kind of pales in comparison of a scary 23.3% incidence of epithelial ingrowth (shudder). Am I seriously expected to take comfort in the "reasonable visual and refractive outcomes"?

Retreatment of residual refractive errors with flap lift laser in situ keratomileusis.

To investigate the outcomes of flap lift laser-assisted in situ keratomileusis (LASIK) for residual refractive errors.

In this prospective study, 60 eyes of 48 patients (mean age 36 years; age range 23-53 years) underwent flap lift retreatment surgery following initial LASIK for the correction of residual refractive errors. All treatments were wavefront guided using the VISX S4 Star excimer laser. The main outcome measures were predictability, safety, efficacy, and stability.

Following retreatment, epithelial ingrowth occurred in 23.3% (n=14) of eyes, which required a flap lift and scrape procedure in 4 eyes and a second flap lift and scrape procedure in 2 eyes. De novo dry eye occurred in 8.3% (n=5) of eyes. At 6 months, the mean (±SD) post-retreatment Snellen decimal uncorrected visual acuity (UCVA), sphere, cylinder, spherical equivalent (SE), defocus equivalent (DE), and best corrected visual acuity (BCVA) was 1.03±0.23, 0.08±0.34 diopters (D) (range -0.75 to +1.25 D), -0.53±0.37 D (range 0 to -1.75 D), -0.04±0.34 D (range -1.11 to +1.04 D), 0.29±0.41 D (range 0 to 1.94 D), and 1.13±0.15 (range 0.5 to 1.5), respectively. Seventy-three percent (n=44) of eyes had an UCVA equal to or greater than 1 (6/6), 88.3% (n=53) and 98.3% (n=59) of eyes were within ±0.50 D and ±1.00 D of SE, respectively, and 3.3% (n=2) of eyes lost 1 line of BCVA.

A high incidence (23.3%, n=14) of epithelial ingrowth occurred following retreatment surgery and de novo dry eye occurred in 8.3% (n=5) of eyes. Despite this, reasonable visual and refractive outcomes were achieved at 6 months post-retreatment.

Eur J Ophthalmol. 2011 Jan-Feb;21(1):5-11.
McAlinden C, Moore JE.
School of Biomedical Sciences, University of Ulster, Coleraine - UK; and Cathedral Eye Clinic, University of Ulster, Belfast - UK.

Newsblurb... dry eye in the cold weather

With the kind of winter much of the country is experiencing it's not surprising to see more mention of dry eye in the press. This one caught my eye:

Cold Weather & Health: Fact, Fiction

Cold weather can also impact the eyes--Ron Chu has dry eye syndrome and last week's cold, dry air was brutal...

Fine, fair enough. But get a load of this:

"It actually worsened my dry eye condition so it felt like sand or grit in my eye so it makes it very difficult to wear contacts," Ron said. "It was just unbearable."

Ron had to use artificial tears every fifteen minutes.

Oh, my, word. Forget the weather factor. Who in their right mind is going to continue wearing contacts when they're putting in drops every fifteen bloomin' minutes? One hopes this gentleman will come to his senses, put on a pair of glasses and hightail it to his eye doctor. One also hopes his doctor is not the type to push every envelope to keep this patient in contacts, at least not until this dry eye thing is under FAR better control.

Abstract: Delivering glaucoma meds in PF dry eye drops

Comparison of the in vitro tolerance and in vivo efficacy of traditional timolol maleate eye drops versus new formulations with bioadhesive polymers.

To assess the in vitro tolerance and in vivo efficacy of new unpreserved formulations of timolol maleate (TM) in aqueous solutions of bioadhesive polymers used for dry eye treatment and to compare them with three traditional TM formulations: unpreserved Timabak®, BAK-preserved Timoftol® and BAK-preserved Timolol Sandoz®.

New formulations were composed of TM (0.5%) and carboxymethyl cellulose (0.5%), hyaluronic acid (0.2%) or hydroxypropylmethyl cellulose (0.3% or 0.5%). In vitro tolerance was determined in human corneal-limbal epithelial cells and normal human conjunctival cells. The ocular hypotensive effect was evaluated measuring IOP in rabbit eyes for 8 hours.

In all cases, cell survival following exposure to the formulations was greater in the new unpreserved TM formulations than in the traditional TM solutions (BAK-preserved and unpreserved). Additionally, the new formulations were demonstrated to maintain the hypotensive effect of TM in different magnitudes. The maximal hypotensive effect was reached by TM 0.5% in carboxymethyl cellulose 0.5% (32.37%).

We demonstrated that new unpreserved formulations of TM with bioadhesive polymers were able to decrease IOP in rabbits and reach values closer to traditional solutions. Furthermore, new formulations presented a significantly higher in vitro tolerance than the same compound in traditional formulations. Although unpreserved formulations are usually more expensive, preservative-free antiglaucoma eye drops should improve compliance and adherence in the medical treatment of glaucoma. Bioadhesive polymers could be proposed to be part of antiglaucoma formulations to reduce ocular toxicity, improve drug efficacy and protect the ocular surface in long term therapies.

Invest Ophthalmol Vis Sci. 2011 Feb 4. [Epub ahead of print]
Andrés-Guerrero V, Vicario-de-la-Torre M, Molina-Martínez IT, Benítez-Del-Castillo JM, García-Feijoo J, Herrero-Vanrell R.
Department of Pharmacy and Pharmaceutical Technology, School of Pharmacy, Complutense University, 28040 Madrid, Spain.

Abstract: Comparing 3 different artificial tears

Efficacy of 3 different artificial tears for the treatment of dry eye in frequent computer users and/or contact lens users.

To compare the efficacy of 3 different artificial tears (AT) acting primarily in one of the 3 tear film layers (Tears Again®, lipidic; Opticol®, aqueous; Optive®, mucin) in recovering the tear film changes in patients with dry eye symptoms due to external causes.

A total of 27 patients, with dry eye symptoms associated with extra hours of computer or contact lenses use, were randomized to 4 treatment groups: A received Tears Again®; B received Optive®; C received Opticol®; D received no treatment (control). Patients were observed in 3 visits: day 0, day 7, and day 30. Tear break-up time (TBUT) and Schirmer tests and the Ocular Surface Disease Index were performed. Data analysis was performed.

There were no significant differences between the groups. From day 0 to day 30, there was a decrease in the number of eyes with abnormal TBUT (not significant) and Schirmer (significant in A, B, D; p<0.031). There was an increase in the average TBUT for all groups (significant in A, C; p<0.001) and a decrease in the average Schirmer value in groups B, C, and D (not significant) and an increase in group A (p=0.002). There was a decrease in the average Ocular Surface Disease Index value in all groups (p<0.045).

All AT were efficient at recovering the tear film, but those acting primarily on the internal and intermediate layer led to a mild decline on lachrymal production. An association of different kinds of AT acting on each layer can be the best treatment for corneal surface diseases affecting eye lubrication.

Eur J Ophthalmol. 2011 Feb 4. pii: B27977C1-AD35-487C-9E0F-E71B087DAEE6. [Epub ahead of print]
Calvão-Santos G, Borges C, Nunes S, Salgado-Borges J, Duarte L.
Ophthalmology Department, Centro Hospitalar de Entre o Douro e Vouga-Unidade de Santa Maria da Feira, Santa Maria da Feira - Portugal.