At this year’s ARVO meeting, researchers present new insights on presbyopic contact lens wear, contact lens wearing comfort, ocular rosacea, corneal infections, drug resistance and dry eye.
One study investigated whether improved multifocal contact lens performance reported in the literature was actually reflected in clinical practice.6542/D1006 A total of 16,680 presbyopic lens fits in 38 countries were reviewed. Of the fits, 29% were fit with multifocals, 8% with monovision and 63% with single vision lenses. The evidence suggested that more multifocal lenses than monovision lenses were being fitted for presbyopes, compared to fits between 1988 and 1989. The researchers concluded that this increased usage was likely due to the improved visual performance of multifocal lenses.
Researchers also sought to quantify the multiple dimensions of ghosted images associated with presbyopic contact lens designs.6546/D1010 Ten best-corrected patients viewed several series of computationally-generated, simulated, ghosted images on a high-resolution monitor. Images were of 20/160 “R” letters, each containing a focused and a defocused component. Each series contained 40 to 50 images spanning a range of a single dimension of ghosting: direction of ghost, magnitude of offset of ghost from focused image, relative intensity of focused and blurred images and blur.
Regardless of ghost letter size and orientation, patients’ responses were within one rating unit of expected findings in more than 95% of trials for all dimensions when they were asked to directly match a single dimension of ghosting. Using a newly developed questionnaire, the patients could quantify ghosting into four dimensions with a very high degree of accuracy. The researchers concluded that improved quantification of the multiple dimensions of ghosting observed in presbyopic designs can drive changes in lens design and fitting.
Single Use and Comfort
Reports have indicated replacement of single-use hydrogel lenses during the day doesn’t improve end-of-day ocular comfort. A study assessed whether the same principle applied to silicone hydrogel lenses.6490/D954 Twenty-four participants were instructed to wear new SiHi contact lenses for 10 hours on three separate days. During two of the days, patients had their lenses removed, then either had new lenses or the same lenses reinserted. For the third day, lenses were worn uninterrupted for 10 hours.
Comfort decreased significantly after 10 hours of uninterrupted lens wear. These results confirmed that for this SiHi material lens, replacement doesn’t improve end-of-day ocular comfort. Taken with previous findings, this conclusion suggests that, irrespective of lens type, end-of-day discomfort is not primarily caused by lens-based deterioration. End-of-day discomfort is more likely due to changes within the eye or its adnexa.
Dry Eye and Lens Compliance
How much is dry eye associated with compliance factors in contact lens wear? To try to answer this question, researchers looked at data derived from a compliance survey in a cross-sectional study of contact lens wearers, including those who had dry eye and those who did not.6519/D983
Although perceived ease in lens care was rated lower by the dry eye group, their lens rub compliance was significantly better than the non-dry eye group. While this finding needs to be verified with a larger sample, the results indicate that factors other than compliance could play a larger role in contact lens-related dry eye.
In a related study, researchers compared comfort, adverse events and compliance in patients who were fitted in contact lenses as children (≤ 12 years of age) vs. those who were fitted as teenagers (≥ 13 years of age).6499/D963 A survey was completed by 175 respondents, 86 of whom had been fitted as children (71% female) and 89 of whom had been fitted as teenagers (63% female).
What were the results of the investigation? Fitting children at 12 years or younger was not associated with a greater frequency of poor comfort, prior adverse events or poorer compliance after 10 years of soft contact lens wear.
Infiltrative Events in Lens Wear
Researchers evaluated risk factors for corneal infiltrative events among soft contact lens wearers.6488/D952 In a 2010 case control study involving five academic eye centers, researchers considered the association of symptomatic soft contact lens-related corneal infiltrative events with lens material, lens care products and other risk factors.
Corneal infiltrative events were positively associated with younger patient age, extended wear and reusable soft contact lenses. The leading soft contact lens and lens care product brands were not significantly associated with development of these events in any model. Among daily wear users, the use of silicone hydrogels were also a significant risk factor for corneal infiltrative events. Use of daily disposable lenses was protective against these events. Improvements in soft contact lens storage case hygiene and environment were identified as possible mechanisms for reducing risk.
The ongoing issue of antibiotic resistance was revisited in a significant way when researchers compared the 2009 Antibiotic Resistance Monitoring in Ocular MicRorganisms (ARMOR) surveillance study to the 2010 ARMOR study.5844/D1129 Thirty-four sites were enrolled to submit ocular isolates of Streptococcus pneumoniae, Staphylococcus aureus, coagulase-negative Staphylococci (CNS), Pseudomonas aeruginosa and Haemophilus influenzae for antibiotic susceptibility testing. Broth microdilution minimum inhibitory concentrations were determined for 14 to 16 representative antibiotics against 274 isolates, per clinical and laboratory standards institute methods. Isolates were categorized as susceptible, intermediate or resistant, based on systemic breakpoints (where available).
Compared to the 2009 survey, the 2010 survey found that non-susceptibility to penicillin remained steady at 5% among S. pneumoniae isolates, although more strains were resistant in 2010 and fewer were intermediate. Azithromycin resistance rose to 29% in S. pneumoniae. An increase in resistance to azithromycin and oxacillin was noted for S. aureus and coagulase-negative Staphylococci isolates. Meanwhile, moxifloxacin resistance increased in S. aureus. Staphylococci non-susceptibility rates (representing isolates that were drug-resistant or intermediate) were identified as follows: 39% for moxifloxacin, 40% to 41% for gatifloxacin, 65% to 76% for azithromycin and 51% to 63% for oxacillin. Also, 22% of S. aureus isolates were resistant to clindamycin in 2010, showing an increase over the previous year. Imipenem resistance increased to 16% in P. aeruginosa, while tobramycin resistance fell. As in 2009, H. influenzae isolates from 2010 were generally susceptible to all test agents.
The 2010 ARMOR surveillance data showed a general increase in drug resistance, especially among the already problematic Staphylococcal isolates, which revealed an increase in resistance for three to four classes of antibiotics. These results indicate the continued need for judicious use of antibiotic therapy in the treatment of ocular infections and the importance of ongoing, prospective, multi-center surveillance studies of ocular pathogens.
Rosacea and Bacteria
One study found that meibomitis-related keratoconjunctivitis shares a similar clinical entity with ocular rosacea. Ocular rosacea is often seen in acne rosacea and is characterized by lid-margin inflammation and frequent corneal involvement.1504/D902
More than 80% of patients in the study were female in both meibomitis-related keratoconjunctivitis (88%) and ocular rosacea (81%) groups. A history of chalazia was distinctive in both conditions, which both involved meibomitis, corneal infiltrates and superficial corneal vascularization. For both diseases, treatment with antimicrobial agents was shown to be both beneficial and highly effective.
Meanwhile, a study of 500 patients was designed to determine if certain demographic factors and clinical characteristics were associated with types of organisms found in bacterial keratitis.5848/D1133 Baseline demographic factors and the clinical characteristics of culture-proven bacterial keratitis, collected as part of the Steroids for Corneal Ulcers Trial, were analyzed. Cases that involved multiple or unspeciable organisms were excluded. Characteristics included age, gender, duration of symptoms, visual acuity, infiltrate/scar size, depth of ulceration, presence of hypopyon, size of hypopyon, ulcer location and concurrent dacryocystitis.
The researchers concluded that certain demographic factors and clinical characteristics could aid in the differentiation of organisms in bacterial keratitis. P. aeruginosa appeared to be associated with more severe ulcers at presentation. Dacryocystitis had a 7.4-fold increase in odds of being associated with S. pneumoniae.
Solutions designed to protect against infection are being evaluated. Specifically, a study looked at the disinfectant efficacy of povidone-iodine, hydrogen peroxide and multipurpose solutions when used to safeguard against planktonic and adherent bacteria in contact lens storage cases.5838/D1123 The study focused on six commercial multipurpose solutions, a commercial hydrogen peroxide and povidone-iodine. Twelve clinical isolates (six strains of Pseudomonas aeruginosa, one strain of Pseudomonas fluorescens, one strain of Stenotrophomonas maltophilia, two strains of Serratia marcescens, one strain of Alcaligenes xylosoxidans and one strain of Chryseobacterum indologenes) were cultivated in Y culture medium and controlled to 107CFU/ml.
The 4ml of disinfectant and 40μl of the controlled liquid were added in the contact lens cases. After a stationary cultivation period of four hours, culture liquid was collected as planktonic bacteria. The conclusion was that povidone-iodine had an efficacy for disinfection of adherent bacteria to the contact lens storage cases as well as planktonic bacteria.
Researchers surveyed participants in the Cornea Society listserv via an internet-based questionnaire (SurveyMonkey) to assess primarily cornea specialists’ practices and opinions related to treatment of recurrent herpes zoster ophthalmicus.1503/D901 Of 75 respondents (85% of them cornea specialists), 67% said they treated these patients with a combination of oral antiviral and topical corticosteroid medications.
The survey revealed that many cornea specialists treated recurrent or chronic cases of herpes zoster ophthalmicus and that they pursued varying approaches in the use of topical corticosteroids and antivirals, particularly those related to the duration of oral antiviral therapy. Respondents were highly divided over the efficacy of prolonged antiviral therapy to reduce chronic or recurrent disease. Most ophthalmologists were not recommending the zoster vaccine to patients with a history of this disease. Respondents were uncertain if the vaccine could reduce recurrences.
Scleral Contact Lenses
A retrospective review of 860 eyes of 612 patients looked at the effects of scleral contact lenses in the management of keratoconus and corneal transplant patients.6522/D986 The researchers found that scleral contact lenses can lead to significant improvements in visual acuity and are useful in the management of these patients.
MGD and Lid Wiper Epitheliopathy
Researchers evaluated the grade of lid wiper epitheliopathy in individuals who had symptomatic dry eye and reduced meibomian gland function.3740/D873 A total of 24 eligible non-contact-lens-wearing patients (19 females and five males) were examined according to the tenets of the Declaration of Helsinki. Patients were required to report their symptoms by using the Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire. Patients with a SPEED score of greater than or equal to six (maximum score = 28) were considered symptomatic for dry eye. Meibomian gland expression—the only method to determine meibomian gland functionality—was performed using a standardized instrument that exerts ~0.3 PSI over the lower lid meibomian glands.
The researchers found that patients reporting dry eye symptoms were very likely to also have reduced meibomian gland function and lid wiper epitheliopathy. Reduced meibomian gland function indicated a treatment protocol aimed at improving meibomian gland function rather than simply increasing artificial lubrication, as might be indicated for isolated liper wiper epitheliopathy.
This small study suggested a need to perform standardized meibomian gland evaluation on all patients who have symptomatic dry eye. Evaluating meibomian gland function may optimize treatment plans.