It’s always difficult to select just a few abstracts from this topic area. We encourage you to sift through the remaining abstracts for the many clinical pearls contained in the proceedings.
Dry Eye and MGD
Sjögren’s syndrome (SS) can be missed when examining a patient with known dry eye. Researchers from Maryland and Turkey have found that some tests can increase the likelihood that a Sjögren’s patient can be identified within a larger pool of patients.3363/D949 In a retrospective review of 1,538 patients, 237 were selected based on their Schirmer test scores to undergo further testing. But, out of the 237 patients, only 89 were finally diagnosed with SS. Researchers point out other factors that this group had in common as highlights for practitioners to look at when examining dry eye patients: presence of dry mouth, Raynaud’s phenomenon, corneal staining and family history of systemic lupus erythematosus. These findings can guide practitioners when recommending a patient for further serologic testing, say researchers.
Gene expression in the meibomian gland accompany meibomian gland dysfunction and may even shed light on the pathogenesis of MGD, report researchers in Boston.3401/D987 After surgical procedures, researchers obtained six samples of eyelid tissue from both MGD patients and controls. They isolated the meibomian glands and processed them for RNA extraction. The findings? MGD is associated with significant alterations in the expression of nearly 400 genes in the human meibomian gland. Levels of 197 transcripts were significantly increased, while the expression of 184 genes was significantly decreased. Main effects of this expression include keratinization and inflammation, which researchers suggest could play a role in the pathogenesis of MGD.
Does the movement of the bulbar conjunctiva play a role in ocular dryness? It provides a good index for ocular dryness, say researchers from Japan.1922/D853 Using a high-speed camera, they tracked the size and location of superficial conjunctival blood vessels in control and dry eye patients. The dry eye patients demonstrated greater rates of blood vessel position change upon each blink, and this greater rate was also strongly associated with a poor tear film break-up time. But, after administration of lubricant in both eyes, the magnitude of change in the dry eye group became the same as that in the control group.
The long-term safety profile for patients who undergo intraductal meibomian gland probing for obstructive MGD seems good, say researchers in Florida.6283/D911 Out of the group of 25 patients who underwent treatment, seven needed retreatment about eight months after the procedure. Nearly one and a half years after first treatment, no long-term adverse effects have been noted. Very likely, devices to perform this procedure will be marketed in the near future.
Signs and symptoms aren’t necessarily equivalent when it comes to dry eye evaluation, report researchers.6246/D874 Researchers drew data from the RESTORE study and noted that OSDI scores and Schirmer test scores only agreed 28% of the time. And, practitioner-reported symptom severity differed significantly from OSDI severity for ocular discomfort, ocular fatigue and visual disturbance—agreement here averaged 27.6%. Bottom line: Make sure to fully assess both signs and symptoms when addressing a patient’s case.
Patients with moderate or severe MGD have a higher incidence of dyslipidemia than the general population, found researchers in Houston.6249/D877 What contributes to this increase in total cholesterol? Elevated serum high-density lipoprotein, which has not previously been associated with a disease state. Researchers suggest that patients with MGD should be screened for dyslipidemia.
What is the association between episcleritis and dry eye disease? Patients with episcleritis are 3.3 times more likely to be concurrently diagnosed with dry eye, report researchers in Birmingham, Ala.6252/D880 The retrospective study examined 64 known episcleritis patients and 3,327 dry eye patients. Of these, 0.33% were also diagnosed with episcleritis, but the episcleritis patients were much more likely to be concurrently diagnosed with dry eye.
Can Acupuncture Treat Dry Eye?
Acupuncture can improve the quality and quantity of the rabbit tear film, lessening dry eye, researchers in China found.6260/D888
Ten rabbits underwent 10 acupuncture sessions, and a tear sample was
collected before and after each session. Researchers found increased
tear quantities and several up-regulated proteins after acupuncture,
and note that these results indicate a positive effect—if not treatment
of dry eye, then another route for management. At least one large-scale
study in the U.S. is currently studying the effects of acupuncture on
dry eye, so stay tuned for results.
Contact Lenses
How likely are soft contact lens patients to experience a second corneal inflammatory event? Researchers in Australia followed 1,051 patients who were using various combinations of silicone hydrogel lenses and either hydrogen peroxide care systems or multipurpose solutions.1538/D829 Of these, 85 experienced a first corneal inflammatory event, 17 of which were discharged from the study. Fifteen of the remaining 68 experienced a second event, and nearly one-third of them were more severe than the first. So, the rate of incidence for the first event was 3.3% for hydrogen peroxide system users, and 10.3% for multipurpose solution users. If a patient experienced a first event, he or she had an 8.8% chance of a second, more severe event. Researchers note the lower likelihood of events with hydrogen peroxide systems.
But, organic material (e.g., tear film components) can lessen the efficacy of hydrogen peroxide against Serratia marcescens in prolonged storage situations.3410/D1027 Researchers based their study on previous findings in which similar results developed when S. marcescens and organic material was tested against several multipurpose solutions. In this study, researchers used five isolates with and without organic matter. Three lots of 3% hydrogen peroxide were assessed against each strain. At four, six and 24 hours, there were no significant differences among samples; however, at 48 hours and one week, significantly poorer efficacy was observed in the presence of organic soil vs. clean samples—the bacteria had regrown. Four of the five isolates showed significant growth after one week’s storage. Researchers stress that hydrogen peroxide should be changed every 24 hours, and extended storage should be avoided.
Pseudomonas aeruginosa adheres more strongly than Staphylococcus aureus to silicone hydrogels, regardless of material type, found researchers in Australia and Texas.3434/D1051 Within each bacterial type, however, there was a difference in rates of adhesion to each polymer. Three strains each of P. aeruginosa and S. aureus were tested against nine silicone hydrogel materials. For S. aureus, adhesion rates were highest with lotrafilcon A and lowest with asmofilcon A. P. aeruginosa adhered most strongly to comfilcon A and least to balafilcon A.
When it comes to lens cases, contamination is very common, and continues to be a topic of much research and interest. Contamination from such a source as the lens case can result in serious ocular infection. So, cleaning the case and using the proper case/solution combination can minimize contamination.
Researchers examined cases of patients who all wore lenses of the same material and a variety of lens care solutions.1511/D802 After one month, cases were collected and sampled for the presence of any microbes. Of the 160 cases, 86% were contaminated—most frequently with gram-positive bacteria, then with gram-negative bacteria, and least commonly with fungus. Cases used with Opti-Free Express solution (Alcon) were less contaminated (76% of these cases showed contamination) than those used with AQuify (CIBA Vision), ClearCare (CIBA) or Opti-Free RepleniSH (Alcon).
When you discuss frank risks with patients, they may seem willing to comply with their lens care regimen. However, researchers in Dallas have found that despite patient awareness of such risks and seeming compliance, many patients still exhibit risky behaviors regarding lens wear.1514/D805 In this three-month prospective study, 162 patients were questioned about their lens care practices and general knowledge on the use of contact lenses and potential risks associated with lens wear. Nearly 87% of patients perceived themselves as compliant with their prescribed lens care regimens, and 40.7% reported a positive history for some form of contact lens-related complication. Almost 80% reported an awareness of risk factors with lens wear, but 14.2% admitted to sleeping in lenses, 29% reported overwearing lenses, 24.1% said they replaced lenses less frequently than directed, 27.8% reported swimming in their lenses, and nearly 10% admitted topping off lens solution either regularly or occasionally. Researchers note that, when these numbers are extrapolated over the entire lens-wearing population, this may account somewhat for the persistent incidence of complications or infection associated with lens wear.
Mucin balls, which frequently present in patients who wear silicone hydrogel lenses, are associated with a significantly decreased incidence of corneal inflammatory events.1517/D808 For one year, researchers followed 205 patients with a continuous wear regimen of silicone hydrogel lenses. More than half of patients displayed mucin balls during at least one visit, and about one-third displayed repeated episodes. Risk of a corneal inflammatory event was 0.35 if a single event of mucin balls was detected, and it was only 0.17 if a patient had repeated episodes. Bottom line: Repeated presence of mucin balls was associated with an 84% decreased risk of experiencing a corneal inflammatory event. Researchers posit that the presence of the mucin balls may indicate a thicker, concentrated mucus layer that presents upregulation of the immune response system against bacterial antigens.
Extended wear is still a big factor in contact lens-related adverse events as is the use of multipurpose solution.1524/D815 This retrospective review of 3,549 patients between the ages of eight and 33 found that odds of infection peaked between the ages of 15 and 25, and that extended wear and multipurpose solution use were significant factors in these events. Patients between the ages of eight and 13 experienced very low risk of any event.
Corneal Infection Complicates EBMD
Corneal infection is a potential complication of epithelial basement dystrophy, found researchers in Philadelphia.2885/D1109 In this retrospective chart review, 10 patients with infectious keratitis due to underlying EBMD changes were identified. Pathogens included S. aureus, S. epidermidis, P. aeruginosa, and Candida. All patients demonstrated infiltrates; nine had an epithelial defect; seven had stromal edema; and three had hypopyon. Four patients required a treatment regimen of fortified antibiotics. Researchers suggest that eye care practitioners take infection into consideration when counseling patients about the prognosis and treatment of EBMD, as it may be a significant possibility and present more severe side effects.
Corneal Infections
Antimicrobial susceptibility patterns have remained relatively stable over the last five years, according to Ocular TRUST.2411/D959 While fluoroquinolones display nearly identical susceptibility profiles, trimethoprim achieved better success rates against staphylococcal infections that required culturing. Anywhere from 38% to 54% of S. aureus isolates, and from 57% to 68% of coagulase-negative staphylococci were methicillin-resistant. In these cases, trimethoprim was most consistently successful, with rates greater than 98% against MSSA and greater than 93% against MRSA. Tobramycin, on the other hand, was only 55% successful against MRSA. The fluoroquinolones all showed rates of roughly 80% against MRSA.
Nevertheless, while these rates are good, MRSA and methicillin-resistant S. epidermidis infections are still increasing in frequency.2412/D960 Researchers used data from The Surveillance Network, an electronic database of susceptibility data, to track rates of resistance to currently prescribed fluoroquinolones—specifically, oxacillin, ciprofloxacin, levofloxacin, gatifloxacin and moxifloxacin—over the last 10 years. MRSA rates of resistance against oxacillin have increased from 25% in 1999 to 45% in 2008. Against ciprofloxacin and levofloxacin, MRSA resistance rates increased 10% from 1999 to 2002 and fluctuated between 27% and 38% between 2002 and 2008. MRSE resistance to oxacillin ranged from 62% to 72% across the time period examined. Its resistance to ciprofloxacin and levofloxacin increased 20% between 2000 and 2004, and by 2008, MRSE resistance rates against ciprofloxacin were 37%, and against levofloxacin, 52%. Between 2006 and 2009, MRSA is 59% resistant to moxifloxacin, 64% resistant to ciprofloxacin, 69% resistant to levofloxacin and 72% resistant to gatifloxacin. MRSE is 53% resistant to ciprofloxacin, 57% resistant to moxifloxacin, 65% resistant to gatifloxacin and 75% resistant to levofloxacin.
Proper treatment can only stem from a correct diagnosis, however. Corneal specialists in a study out of California and India correctly differentiated images of bacterial vs. non-bacterial corneal ulcers less than 70% of the time.2880/D1104 Those who practice in areas with high incidence of fungal keratitis performed only marginally better. Eighty photographs with lab-confirmed diagnoses were given to practitioners, who were asked to predict culture results, gram stain results and to rank the traits they’d based their diagnosis on. Clinicians accurately distinguished bacterial vs. fungal etiology only 65.5% of the time. Gram stain, genus and species were accurately predicted 48.2%, 25.7% and 20.9% of the time, respectively. Traits most commonly used by doctors to identify the infection (correctly or not) were infiltrate border appearance, surrounding stromal haze and presence of hypopyon.
