Penny A. Asbell

Age-related cataract

Cataract, opacification of the lens, is one of the commonest causes of loss of useful vision, with an estimated 16 million people worldwide affected. Several risk factors have been identified in addition to increasing age--genetic composition, exposure to ultraviolet light, and diabetes. However, no method to halt the formation of a cataractous lens has been shown to be effective. Nevertheless, advances in surgical removal of cataracts, including small-incision surgery, use of viscoelastics, and the development of intraocular lenses, have made treatment very effective and visual recovery rapid in most cases. Despite these advances, cataract continues to be a leading public-health issue that will grow in importance as the population increases and life expectancy is extended worldwide.

Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study One Year After Surgery

The Prospective Evaluation of Radial Keratotomy (PERK) study is a nine-center, self-controlled clinical trial of a standardized technique of radial keratotomy in 435 patients who had physiologic myopia with a preoperative refraction between -2.00 and -8.00 diopters. The surgical technique consisted of eight incisions using a diamond micrometer knife with blade length determined by intraoperative ultrasonic pachymetry and the diameter of central clear zone determined by preoperative refraction. At one year after surgery, myopia was reduced in all eyes; 60% were within +/- 1.00 diopter of emmetropia; 30% were undercorrected and 10% were overcorrected by more than 1.00 diopter (range of refraction, -4.25 to +3.38 D). Uncorrected visual acuity was 20/40 or better in 78% of eyes. The operation was most effective in eyes with a refraction between -2.00 and -4.25 diopters. Thirteen percent of patients lost one or two Snellen lines of best corrected visual acuity. However, all but three eyes could be corrected to 20/20. Ten percent of patients increased astigmatism more than 1.00 diopter. Disabling glare was not detected with a clinical glare tester, but three patients reduced their driving at night because of glare. Between six months and one year, the refraction changed by greater than 0.50 diopters in 19% of eyes.

Minimal Clinically Important Difference for the Ocular Surface Disease Index

OBJECTIVE To assess the minimal clinically important difference (MCID) for the Ocular Surface Disease Index (OSDI; Allergan Inc, Irvine, California, holds the copyright), a 12-item patient-reported outcome questionnaire designed to quantify ocular disability due to dry eye disease. METHODS Study data were collected within the Restasis Review of Efficacy and Safety vs Tears in the Relief of Dry Eye (RESTORE), an observational registry. A clinician global impression (CGI) and a subject global assessment (SGA) served as anchors to estimate the MCID for the overall OSDI score (range, 0-100). The overall OSDI score defined the ocular surface as normal (0-12 points) or as having mild (13-22 points), moderate (23-32 points), or severe (33-100 points) disease. RESTORE patients were included if they completed the OSDI at the baseline visit and at a follow-up visit and had a global change rating (SGA or CGI). RESULTS Three hundred ten patients were included (82.3% white and 81.6% female [mean age, 57.8 years]). The CGI and SGA correlated with the OSDI score change for all OSDI categories except the normal category. The MCID ranged from 7.0 to 9.9 for all OSDI categories. The MCID ranged from 4.5 to 7.3 for mild or moderate disease and from 7.3 to 13.4 for severe disease. CONCLUSIONS Using observational data, we estimated the MCIDs for different baseline OSDI categories of dry eye disease. These results will assist clinicians and researchers when interpreting OSDI score changes.

Ocular TRUST: Nationwide Antimicrobial Susceptibility Patterns in Ocular Isolates

PURPOSE Ocular Tracking Resistance in U.S. Today (TRUST) annually evaluates in vitro antimicrobial susceptibility of Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae to ciprofloxacin, gatifloxacin, levofloxacin, moxifloxacin, penicillin, azithromycin, tobramycin, trimethoprim, and polymyxin B in national samples of ocular isolates. DESIGN Laboratory investigation. METHODS Prospectively collected ocular isolates (197 S. aureus, 49 S. pneumoniae, and 32 H. influenzae) from 35 institutions and archived ocular isolates (760 S. pneumoniae and 356 H. influenzae) from 34 institutions were tested by an independent, central laboratory. Mean minimum inhibitory concentrations that would inhibit growth of 90% of the tested isolates (MIC(90)) were interpreted as susceptible, intermediate, or resistant according to standardized breakpoints for systemic treatment. S. aureus isolates were classified as methicillin susceptible (MSSA) or methicillin resistant (MRSA). RESULTS MSSA or MRSA susceptibility patterns were virtually identical for the fluoroquinolones, that is, MSSA susceptibility was 79.9% to 81.1% and MRSA susceptibility was 15.2%. Trimethoprim was the only agent tested with high activity against MRSA. All S. pneumoniae isolates were susceptible to gatifloxacin, levofloxacin, and moxifloxacin; 89.8% were susceptible to ciprofloxacin. H. influenzae isolates were 100% susceptible to all tested agents but trimethoprim. Ocular TRUST 1 data were consistent with the eight-year longitudinal sample of archived ocular isolates. CONCLUSIONS The fluoroquinolones were consistently active in MSSA, S. pneumoniae, and H. influenzae. After more than a decade of intensive ciprofloxacin and levofloxacin use as systemic therapy, 100% of ocular S. pneumoniae isolates were susceptible to gatifloxacin, levofloxacin, and moxifloxacin; nonsusceptibility to ciprofloxacin was less than 15%. High-level in vitro MRSA resistance suggests the need to consider alternative therapy to fluoroquinolones when MRSA is a likely pathogen.

The Intrastromal Corneal Ring Segments: Phase II Results far the Correction of Myopia

OBJECTIVE The purpose of the study was to evaluate the safety and efficacy of the intrastromal corneal ring segments (ICRS) for the correction of myopia. DESIGN A 2-year phase II clinical trial of ICRS was initiated in May 1995. The investigational plan specifies that 150 patients with sighted eyes, requiring myopic corrections from -1.00 to -6.00 diopters (D), will each receive ICRS in 1 eye. The patient population will be divided into approximately five patients per ICRS thickness (0.25, 0.30, 0.35, 0.40, and 0.45 mm) per site. Six investigational sites are participating in the trial. PARTICIPANTS Fifty-nine men and 43 women requiring myopic corrections were enrolled at four U.S. investigational sites. These 102 patients each received the ICRS product in 1 eye. INTERVENTION Correction of myopia. MAIN OUTCOME MEASURES Efficacy of ICRS was assessed with respect to the trial endpoints of predictability of refractive effect, uncorrected visual acuity (UCVA), stability of UCVA, maintenance of best spectacle-corrected visual acuity and stability of refractive effect. RESULTS As shown by the available month-3 data (99 patients; all device thicknesses), 95 (96%) of 99 patients had a UCVA of 20/40 or better. Ninety-eight (99%) of 99 patients were within 2 lines of their preoperative best spectacle-corrected visual acuity. The average change (with standard error) in cycloplegic refraction (spherical equivalent) achieved by ICRS thickness was -1.27 +/- 0.09 D (0.25 mm), -2.13 +/- 0.16 D (0.30 mm), -2.56 +/- 0.15 D (0.35 mm), -3.77 +/- 0.37 D (0.40 mm) and -4.16 +/- 0.24 D (0.45 mm). Seventy-seven percent (76/99) of the patients were within +/-1.00 D of their intended correction. When the ICRS was removed in two cases, both patients returned to within 0.75 D of their preoperative manifest refraction. CONCLUSIONS The ICRS appears to be a viable and effective alternative for the treatment of myopia. Additionally, as indicated by the explant data, the ICRSs refractive effect may be reversible upon removal of the device.

Increasing prevalence of methicillin resistance in serious ocular infections caused by Staphylococcus aureus in the United States: 2000 to 2005

PURPOSE: To report the nationwide prevalence of methicillin resistance in serious ocular infections involving Staphylococcus aureus and profile in vitro antimicrobial susceptibility of S aureus from ocular isolates over time. SETTING: Proprietary electronic database. METHODS: Data on S aureus submitted to The Surveillance Network (TSN) by more than 200 laboratories in the United States from January 2000 to December 2005 were reviewed. The prevalence of methicillin resistance in S aureus ocular infections and in vitro susceptibility to antibiotic agents commonly used to treat or prevent ocular infections were determined. RESULTS: The proportion of S aureus infections culture‐positive for methicillin‐resistant S aureus (MRSA) increased from 29.5% in 2000 to 41.6% in 2005. The MRSA ocular isolates were multidrug resistant; that is, in vitro resistance to 3 antibiotic agents or more, including all fluoroquinolones tested. CONCLUSIONS: Multidrug‐resistant MRSA is increasing in serious ocular infections. Based on the rate of increase in the TSN database, MRSA cultures from serious ocular infections could be more common than methicillin‐susceptible S aureus within 2 to 3 years. Large‐scale national surveillance programs are needed to monitor in vitro antimicrobial resistance trends in ocular isolates.

Two-year outcomes of intrastromal corneal ring segments for the correction of myopia ☆

OBJECTIVE To evaluate the safety and efficacy of Intrastromal Corneal Ring Segments (ICRS) for the correction of myopia. DESIGN Nonrandomized, comparative trial. PARTICIPANTS Patients enrolled in the United States Food and Drug Administration phase II and phase III clinical trials of the ICRS had best spectacle-corrected visual acuity (BSCVA) of 20/20 or better, myopia of -1.00 to -3.50 diopters (D), and a cylindrical correction of 1.00 D or less as measured by manifest refraction. INTERVENTION Surgical correction of myopia with an ICRS. MAIN OUTCOME MEASURES Efficacy was assessed by predictability of refractive outcome (deviation from predicted cycloplegic refraction spherical equivalent), stability of refractive effect, and postoperative uncorrected visual acuity. Safety was assessed by adverse events, maintenance or loss of preoperative BSCVA, and induced manifest refraction cylinder. RESULTS Four hundred fifty-two patients were enrolled at 11 investigational sites in both studies. Of the 454 surgical attempts, 449 received an ICRS in one eye (0.25, 0.30, and 0.35 mm in 148, 151, and 150 eyes, respectively). First surgeries were attempted in 452 patients. An ICRS was successfully implanted in 447 initial eyes, and 5 surgeries were discontinued. Of the five discontinued surgeries, three patients subsequently exited from the study, and two patients went on to have the ICRS implanted in the second eye, bringing the total number of successful implants to 449 patient eyes. Month 24 postoperative follow-up was completed on 358 patients (80%). At month 24, 328 of 354 eyes (93%) were within +/-1.00 D of predicted refractive outcome. Refraction changed by 1 D or less in 97% of eyes (421/435) between 3 and 6 months after implantation and in 99% (343/348) between months 18 and 24. Before surgery, 87% of eyes (390/448) saw worse than 20/40 uncorrected; 24 months after surgery, 55% of eyes (196/358) saw 20/16 or better, 76% (271/358) saw 20/20 or better, and 97% (346/358) saw 20/40 or better. Although two eyes (2/358; 0.5%) lost two or more lines of BSCVA at 24 months; visual acuity in both was 20/20 or better. Intraoperative complications included anterior corneal surface perforation (three eyes) and anterior chamber perforations (two eyes, one during an attempted exchange procedure); all healed spontaneously without suturing and without loss of BSCVA. The ICRS was repositioned in five eyes to increase correction. Postoperative complications in one eye each were infectious keratitis, shallow segment placement, and loss of two lines of BSCVA at two or more consecutive examinations (subsequently regained). CONCLUSIONS The ICRS safely, predictably, and effectively reduced or eliminated myopia of -1.00 to -3.50 D. The refractive effect was stable over time.

Three-year Results of the Prospective Evaluation of Radial Keratotomy (PERK) Study

The Prospective Evaluation of Radial Keratotomy (PERK) study is a nine-center clinical trial of a standardized technique of radial keratotomy in 435 patients who had simple myopia with a preoperative refractive error between -2.00 and -8.00 diopters (D). We report results for one eye of each patient. The surgical technique consisted of eight incisions using a diamond micrometer knife with the blade length determined by intraoperative ultrasonic pachymetry and the diameter of the central clear zone determined by the preoperative refractive error. At three years after surgery, 58% of eyes had refractive error within one diopter of emmetropia; 26% were undercorrected, and 16% were overcorrected by more than one diopter. Uncorrected visual acuity was 20/40 or better in 76% of eyes. The operation was more effective in eyes with a preoperative refractive error between -2.00 and -4.37 diopters. Between one and three years after surgery, the refractive error changed by 1.00 diopter or more in 12% of eyes, indicating a lack of stability in some eyes.

Clinical Guidelines for Management of Dry Eye Associated with Sjögren Disease

PURPOSE To provide a consensus clinical guideline for management of dry eye disease associated with Sjögren disease by evaluating published treatments and recommending management options. DESIGN Consensus panel evaluation of reported treatments for dry eye disease. METHODS Using the 2007 Report of the International Workshop on Dry Eye (DEWS) as a starting point, a panel of eye care providers and consultants evaluated peer-reviewed publications and developed recommendations for evaluation and management of dry eye disease associated with Sjögren disease. Publications were graded according to the American Academy of Ophthalmology Preferred Practice Pattern guidelines for level of evidence. Strength of recommendation was according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidelines. RESULTS The recommendations of the panel are briefly summarized herein. Evaluation should include symptoms of both discomfort and visual disturbance as well as determination of the relative contribution of aqueous production deficiency and evaporative loss of tear volume. Objective parameters of tear film stability, tear osmolarity, degree of lid margin disease, and ocular surface damage should be used to stage severity of dry eye disease to assist in selecting appropriate treatment options. Patient education with regard to the nature of the problem, aggravating factors, and goals of treatment is critical to successful management. Tear supplementation and stabilization, control of inflammation of the lacrimal glands and ocular surface, and possible stimulation of tear production are treatment options that are used according to the character and severity of dry eye disease. SUMMARY Management guidelines for dry eye associated with Sjögrens disease are presented.

Essential Fatty Acids in the Treatment of Dry Eye

Essential fatty acids (EFAs) play many important roles in human biology, affecting organ systems and cellular and intracellular function. Omega-3 and omega-6 EFAs are the precursors of eicosanoids, locally acting hormones involved in mediating inflammatory processes. It is largely via the production of these eicosanoids that the essential fatty acids influence human health and disease. In general, the omega-3 derived eicosanoids are anti-inflammatory while the n-6 pathway eicosanoids promote inflammation. To date, EFAs have been primarily studied with regard to systemic diseases, particularly cardiovascular disease. Currently, no dietary recommendations of EFAs for the prevention or treatment of eye disease exist. The majority of studies concerning EFAs and eye disease have focused on diseases of the retina. This article provides an overview of the current literature regarding EFAs and dry eye disease (DED). Eight studies were identified, including six randomized controlled trials. All the studies preliminarily confirmed that there is a relationship between EFA supplementation and improvement in DED. However, strong conclusions cannot be made yet because of limitations in the research reported. The role of essential fatty acids is an important topic that would benefit from a large, multicenter, randomized clinical trial powered to reach a conclusion regarding the efficacy of essential fatty acids in the treatment of dry eye disease.