This years research focused on corneal infection prevention. But, other topics include dry eye management and surgical procedures. How will these findings affect the way that you practice?

 

Corneal Infection

Many presentations at this years meeting centered on the prevention and management of corneal infection. Some studies compared or measured drug efficacy, while others tested new delivery mechanisms.

Researchers in Japan set out to compare the delivery time and efficacy of a 0.3% ofloxacin drop vs. the thermosetting 0.3% ofloxacin-containing ophthalmic gel WP-0405.1984/D1055 Researchers developed an in vitro dynamic model to simulate the change of ofloxacin concentration on the cornea. The gel and drop were tested on five strains of methicillin-resistant Staphylococcus aureus (MRSA) and coagulase negative Staphylococcus (CNS), and time-dependent changes were measured regularly.

The study found that WP-0405 showed significantly more activity against four of the five MRSA strains for up to eight hours; neither drop was effective against the fifth strain. Against the five CNS strains, WP-0405 demonstrated greater efficacy. Results suggested that a thermosetting gel-based delivery method allowed for greater antibacterial activity than did a drop-based delivery system. Such ophthalmic gels may be used to enhance the efficacy of topical antimicrobial medications.

Another in vitro study focused on managing inflammation by inhibiting cytokine expression.2500/A26 The efficacy of besifloxacin, a new fluoroquinolone that works by inhibiting nuclear factor-kappa B, was compared to that of moxifloxacin, the control in this study. In a dose-dependent manner, besifloxacin performed at least as well as moxifloxacin. In inhibiting transforming growth factor a (TGF-a) and tumor necrosis factor a (TNF-a), besifloxacin outperformed moxifloxacin. Researchers note the need for further investigation.

Researchers from the Aravind Eye Hospital in India and the University of Texas Health Sciences Center tested the viability of anecdotal reports of antibiotic efficacy against Fusarium and Aspergillus strains.2496/A22 The susceptibility of 10 isolates of each fungus was tested in microbroth solution against amoxicillin, cefazolin, chloramphenicol, moxifloxacin, tobramycin and benzalkonium chloride (BAK).

Results showed that BAK had the lowest minimum inhibitory concentration (MIC) for both fungi overall. Chloramphenicol demonstrated some activity against both Fusarium and Aspergillus, while moxifloxacin and tobramycin showed some activity against Fusarium, but not Aspergillus. Researchers concluded that, while beneficial prior to definitive diagnosis, antibiotics lack the MIC range that antifungal treatments (e.g., amphotericin B, used in this study as a control) possess.

 

Dry Eye and Ocular Surface Disease

This years research may signal more comfortable days ahead for dry eye sufferers.

Researchers in Virginia and New York compared the effects of topical loteprednol 0.5% induction therapy prior to topical cyclosporine emulsion to artificial tear use prior to cyclosporine.99/A126 In the study, 118 patients received either artificial tears (control) or loteprednol etabonate 0.5% q.i.d. for two weeks. Then, each patient began cyclosporine b.i.d. and reduced the tears or loteprednol to b.i.d. for six weeks.

Acuity, staining, slit lamp exam and Ocular Surface Disease Index (OSDI) scores were used to measure results. Loteprednol was found to significantly improve the stinging associated with cyclosporine instillation. Also, both groups OSDI scores increased, but the group that used loteprednol improved more.

Researchers recommend that practitioners consider loteprednol use in patients with chronic dry eye disease. This study seems to substantiate the benefit of using a soft steroid, and validates the claim that the use of such steroids carries less risk with prolonged use when compared to other topical steroids.

Researchers in Italy found that autologous serum eye drops successfully relieved patients severe dry eye symptoms.103/A130 Forty-eight patients whose severe dry eye didnt respond to treatment with conventional lubricants were placed on a regimen of autologous serum drops q.i.d. to eight times per day. At three months, patients reported significant relief, and flourescein and lissamine green staining, Schirmer test scores, and tear film break-up time improved.

The researchers note that corneal confocal microscopy is an objective diagnostic tool in cases of tear film disorders. But, dont use autologous serum in patients with dry eye secondary to graft-versus-host disease following a bone marrow transplant, as the autologous serum may only exacerbate the situation.

A study of 630 patients led by researchers in Texas, New Jersey, South Carolina and Florida found that patients who use IOP-lowering medications are more likely to suffer from ocular surface disease.5335/D777 This survey-based study examined glaucoma patients who use topical IOP medications. Of the 630 patients, 305 had an OSDI score of mild, moderate or severe symptoms. Scores tended to be worse for patients who used more than one topical medication. Due to chronic use and preservatives, topical glaucoma medications can be a source of significant ocular toxicity. So, monitor and manage patients accordingly.

 

Researchers found that DSAEK results in slightly better post-op acuity than PK.

Surgery

Penetrating keratoplasty (PK) came under close scrutiny this year. Studies examined indications for it, measured its efficacy vs. that of deep anterior lamellar keratoplasty (DALK) or Descemets stripping automated endothelial keratoplasty (DSAEK), and looked at the likelihood of a rupture post-PK. There is often less chance of rejection with lamellar surgery, so surgeons may tend to opt for it.

St. Louis University researchers examined the indications for a PK referral between 2002 and 2007.1976/D947 In total, 94 PK procedures were performed, and of these, regraft (39.3%) was the most common indication for the procedure, followed by pseudophakic or aphakic bullous keratopathy (30.0%), corneal scar (11.6%), Fuchs dystrophy (8.5%) and ectasia (7.4%). Researchers note that their findings differ from those published by the Eye Bank Association, which examine the same time frame and point to bullous keratopathy as the most common indication for PK.

When performing PK, California researchers found, a femtosecond laser-generated zig-zag incision leads to a shorter recovery period and less induced astigmatism than does conventional trephination.1960/D931 This retrospective review compared two groups of PK patients30 eyes incised by a femtosecond laser (group A) vs. 14 eyes incised via trephination (group B). All PK procedures were closed with the same 24-bite running suture technique.

At three months, the average amount of astigmatism was -2.20D in group A and -4.45D in group B. Throughout follow-up, astigmatism remained less than -3.00D in group A, but more than -3.00D in group B. Of the patients who had normal macular function, 86% of group A and 11% of group B achieved a best-corrected acuity of 20/30 or better.

Two studies compared PK to other surgical procedures: DALK and DSAEK. Researchers in the United Kingdom and Australia compared mid-term outcomes of PK and DALK and found no statistically significant difference when comparing for post-op spherical equivalent, mean refractive cylinder or best-corrected acuity.1973/D944 But, researchers note, although the DALK procedure offered a slightly reduced best-corrected acuity, no DALK pro- cedure examined required regrafting, while two PK procedures failed.

When compared to DSAEK, researchers in Michigan found that PK resulted in a slightly worse post-op visual acuity, on average, and a slightly longer recovery period.1941/D912 Five of the seven patients followed (who all underwent PK originally, then DSAEK in their fellow eye) preferred the vision in their DSAEK eye.

Researchers in Seattle examined a cohort of 31 patients at the University of Washington who underwent PK between 1998 and 2008 and later experienced open-globe injuries.2311/D952 Prognosis was poor in these cases, and researchers noted that mostbut not allruptures occurred at the host-graft junction.

At the last follow-up of 18 cases, acuity was 20/200 or better in only three patients and hand motion or worse in eight patients; six eyes had been enucleated. Of those not enucleated, the graft opacified in eight and cleared in three. Researchers note that a history of trauma should serve as an indicator not to perform PK, but to opt for another procedure.

 

Contact Lenses

This years meeting offered new insights regarding age and ability to wear lenses, lens-related dry eye and the impact of solution on Pseudomonas ability to bind to the lens.

A large, multi-center study found that soft contact lens wear does not increase the progression of myopia in children.2021 Of the participants, 237 wore glasses and 247 wore contact lenses. All were measured annually during the three-year study. At final follow-up, axial growth of spectacle wearers and contact lens wearers only differed by 0.04mm. Spectacle wearers progressed -1.08D + 0.71D, while lens wearers progressed -1.27D + 0.72Da difference of 0.19D, which researchers say is not statistically significant.

Ohio researchers found that current contact lens-related dry eye treatments are not effective, judging by the use of common treatment modalities, including lens refitting and the use of artificial tears or lubricants.4862/D784 They found that ionic and non-ionic high water-content materials played a role in dry eye, while care solutions did not, and they note a need to find more effective treatments and better lens materials.

Researchers in Texas found that the risk for Pseudomonas keratitis is unchanged despite the use of silicone hydrogel daily or long-term lenses.4867/D789 In a 12-month study of 115 patients randomized to wear one of three lens types (lotrafilcon A, lotrafilcon B or galyfilcon A), all patients used Clear Care solution (CIBA Vision) for uniformity and underwent a prior 30-day washout. Researchers measured for Pseudomonas aeruginosa bound to exfoliated corneal cells, central epithelial thickness and surface cell desquamation. Extended lens wear caused a decrease in corneal thickness that recovered during one year. All lens wear decreased epithelial surface cell desquamation, which also adapted over a one-year period. There was no difference between extended or daily wear regarding Pseudomonas tendency to bind to corneal cells. So, researchers conclude, in the absence of a solution-based variable or related corneal damage, Pseudomonas keratitis rates should not change due to lens wear modality. Perhaps, they add, the preservative in the solution interacts with receptors on the corneal epithelial cells.

Dr. Shovlin is in group practice in Scranton, Pa. He edits Reviews Cornea and Contact Lens Q+A and is the clinical editor of Review of Cornea and Contact Lenses.

 

1984/D1055. Nakaya S, Kato A, Ohyama Y, et al. Enhancement and prolongation of antibacterial activity of ofloxacin delivery in a thermo-setting gel.

2500/A26. Cavet ME, Van Der Meid KR, Zhang J, Ward KW. Anti-inflammatory effects of besifloxacin, a novel fluoroquinolone, in primary human corneal epithelial cells.

2496/A22. Day S, Prajna L, Haug S, et al. Are antibiotics effective against Fusarium and Aspergillus?

99/A126. Sheppard JD, Donnenfeld ED. Topical loteprednol 0.5% induction therapy improves topical cyclosporine emulsion tolerability in chronic dry eye disease.

103/A130. Fregona I, Leonardi A, Violato D, et al. Autologous serum eye drops in severe dry eye syndrome: tear function, conjunctival cytology and corneal confocal microscopy investigations.

5335/D777. Godfrey DG, Fechtner RD, Budenz DL, et al. Increased prevalence of ocular surface disease symptoms in glaucoma patients using IOP-lowering medications.

1976/D947. Brothers WB, Hsu H. Trends in indications for penetrating keratoplasty in the academic setting (2002-2007).

1960/D931. Farid M, Chamberlain W, Lin A, Steinert RF. Comparison of visual recovery and astigmatism in 24-bite running penetrating keratoplasty performed with a femtosecond laser zig-zag incision versus conventional trephination.

1973/D944. Ball JL, Funnell CL, Pesudovs K, et al. Mid-term outcomes of penetrating keratoplasty and deep anterior lamellar keratoplasty.

1941/D912. Thompson GW, Spigelman AV. Clinical and subjective outcomes of penetrating keratoplasty vs. DSAEK in fellow eyes.

2311/D952. Brown JS, Slabaugh M, Wu M, Lee JJ. Open globe injuries following PK.

2021. Walline JJ, Joes LA, Sinnott LT, et al. Soft contact lenses do not increase myopia progression in children.

4862/D784. Pamamoorthy P, Sinnott LT, Nichols JJ. Treatment, material, care, and patient-factors in contact lens related dry eye.
4867/D789. Cavanagh HD, Robertson DM. The effect of contact lens care solutions on Pseudomonas binding following hyper-Dk silicone hydrogel contact lens wear.