Charlotte E. Joslin

Between-Eye Asymmetry in Keratoconus

Purpose. To report baseline differences between eyes on key variables in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study cohort compared with a retrospectively assembled group of myopic contact lens wearers without ocular disease. Methods. A total of 1,079 keratoconus patients who had not undergone a penetrating keratoplasty in either eye before their baseline visit were enrolled and examined at baseline. Records from 330 contact lens-wearing myopes were reviewed. Corneal curvature (keratometry), visual acuity, refractive error (manifest refraction), and corneal scarring were measured. Results. The mean differences between keratoconic eyes are as follows (better eye–worse eye for each variable, separately). Flat keratometry: −3.59 ±4.46 D and steep keratometry: −4.35 ±4.41 D; high-contrast best-corrected visual acuity: 7.30 ±6.83 letters; low-contrast best-corrected visual acuity: 8.53 ±7.51 letters; high-contrast entrance visual acuity: 9.03 ±8.40 letters; low-contrast entrance visual acuity: 9.43 ±7.88 letters; spherical equivalent refractive error: 3.15 ±3.84 D; and refractive cylinder power 1.55 ±1.42 D. Twenty-one percent of the keratoconus patients had corneal scarring in only one eye. There is an association between patient-reported unilateral eye rubbing and greater asymmetry in corneal curvature, and between a history of unilateral eye trauma and greater asymmetry in corneal curvature and refractive error, with the rubbed/traumatized eye being the steeper eye most of the time. Conclusions. Keratoconus is asymmetric in the CLEK Study sample.

Higher-order wavefront aberrations in corneal refractive therapy.

Purpose. To assess the changes in higher-order (third through sixth) ocular wavefront aberrations produced by Corneal Refractive Therapy (CRT; Paragon Vision Sciences, Mesa, AZ). Methods. Eighteen eyes of nine myopic subjects were fit with CRT contact lenses. Baseline subjective spherical refraction ranged from −2.25 to −6.00 D (mean ± SD, −3.33 ± 1.26 D), and baseline logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuity was −0.13 ± 0.06 (20/15 Snellen equivalent). Whole-eye ocular wavefront aberrations were measured using a previously validated Shack-Hartmann aberrometer. Measurements were taken at baseline and 1 month after treatment initiation. Nine measurements per dilated subject were taken and averaged. Zernike coefficients were used to calculate the third-, fourth-, fifth-, and sixth-order root-mean-square values for each eye for both 3- and 6-mm pupil sizes, and aberrations were averaged and compared with prior baseline readings. Results. The mean (±SD) myopia reduction was 3.08 ± 0.93 D, resulting in a subjective refraction of −0.22 ± 0.38 D after 1 month of lens wear. Both logMAR uncorrected visual acuity (−0.07 ± 0.18; 20/15− Snellen equivalent) and best-corrected visual acuity (−0.14 ± 0.09) after CRT wear were not significantly different from baseline logMAR best-corrected visual acuity (paired two-tailed t-test; p = 0.41 and 0.65, respectively). Whole-eye aberrations showed a statistically significant increase in higher-order aberrations for both 3-mm (factor of 2.66; p = 0.01) and 6-mm pupils (factor of 2.50; p = 0.005). Each individual higher-order aberration also increased, ranging from a factor of 2.01 to 3.20 for 3-mm pupil sizes and 2.52 to 2.98 for 6-mm pupil sizes. Spherical-like aberrations (S4 and S6) increased by a factor of 1.79 for 3-mm pupil sizes and 2.42 for 6-mm pupil sizes. The Zernike coefficient most affected by CRT was spherical aberration (Z40), which increased from 0.084 ± 0.16 to 0.39 ± 0.16 &mgr;m (p = 0.0002) for 6-mm pupils. Conclusions. Use of current CRT lenses for the reduction of myopia increased higher-order wavefront aberrations and spherical aberration (Z40) in particular.

The relative value of confocal microscopy and superficial corneal scrapings in the diagnosis of Acanthamoeba keratitis.

Purpose: To compare the relative diagnostic value of confocal microscopy and superficial corneal cultures in the diagnosis of Acanthamoeba keratitis by using clinical and microbiologic definitions of disease. Methods: Results of confocal microscopy, superficial corneal smear, and superficial corneal culture were analyzed for validity against 2 different microbiologic and a clinical composite standard for Acanthamoeba keratitis. Results: In patients with both clinical characteristics and objective evidence of Acanthamoeba keratitis, confocal microscopy exhibited a sensitivity of 90.6% (95% confidence interval [CI]: 79.3%-96.9%) and a specificity of 100% (95% CI: 95.0%-100%). In patients with either positive culture or smear evidence of Acanthamoeba keratitis, confocal microscopy showed a sensitivity of 90.9% (95% CI: 78.3%-97.5%) and specificity of 90.1% (95% CI: 81.5%-95.6%). In strictly culture-positive patients, confocal microscopy showed a sensitivity of 92.9% (95% CI: 76.5%-99.1%) and a specificity of 77.3% (95% CI: 67.7%-85.2%). Of the 53 patients with Acanthamoeba keratitis, confocal microscopy was positive in 48 patients, whereas corneal smears and cultures were positive in 30 of 41 and 23 of 42 patients, respectively. Sensitivity of Acanthamoeba culture was 52.8% (95% CI: 38.6%-66.7%) in patients with a clinical diagnosis of Acanthamoeba keratitis. Simultaneous testing of smear and superficial corneal scraping resulted in a sensitivity of 83.0% (95% CI: 70.2%-91.9%), independent of the results of confocal microscopy. Conclusions: As confocal microscopy comes into wider clinical use, it remains in need of clinical and pathologic correlation. When performed and interpreted by an experienced operator, confocal microscopy is both sensitive and specific in the diagnosis of Acanthamoeba keratitis. Contemporaneous corneal scrapings are independently sensitive in the detection of Acanthamoeba keratitis, and a combination of both diagnostic modalities offers the highest likelihood of rapidly and accurately diagnosing Acanthamoeba keratitis in patients with atypical keratitis.

CHARACTERISTICS OF CORNEAL ECTASIA AFTER LASIK FOR MYOPIA

Purpose: There are numerous reports of corneal ectasia after laser in situ keratomileusis (LASIK) for myopia without a consistent definition of this condition or a definitive etiology. We conducted a retrospective analysis of published case reports to describe common characteristics of this postoperative event and compared them with findings from a group of successful LASIK patients. Methods: A MEDLINE search for “LASIK” and “ectasia” yielded 21 relevant articles published before May 2003 (n = 86 eyes, 59 patients). A comparison group (n = 103 eyes, 63 patients) was selected from a clinic-based sample of successful LASIK patients with 12 months of follow-up after treatment. Descriptive statistics are reported as median and interquartile range. Comparisons were performed using the Wilcoxon rank sum, Wilcoxon signed rank, and chi-square tests. Results: Time to diagnosis of ectasia after LASIK was 13 months (6 to 20 months). Residual myopia in the ectasia group was −3.69 D (−6.00 to −2.13 D) and was significantly greater than the comparison group, −0.38 D (−0.75 to 0.00 D), P < 0.001. After surgery, eyes with ectasia had increased corneal toricity 2.87 D (2.00 to 4.9 D) with increased oblique astigmatism 1.3 D (0.23 to 2.89 D) relative to eyes in the comparison group 0.00 D (0.00 to 0.08 D), and a loss of 2 lines (−0.5 to −6 lines) of best spectacle-corrected visual acuity (all P < 0.001). Thirty-five percent of reported cases resulted in subsequent corneal transplantation. Conclusions: Preoperative characteristics of corneal ectasia include worse visual acuity, less corneal thickness, greater residual myopia, and greater corneal toricity than nonectatic eyes. Treatment factors associated with corneal ectasia after LASIK are greater stromal ablation and less residual stromal bed thickness. Postoperative characteristics of corneal ectasia are myopic refractive error with increased astigmatism, worse spectacle-corrected visual acuity, increased corneal toricity with topographic abnormality, and progressive corneal thinning.

Prognostic Factors Affecting Visual Outcome in Acanthamoeba Keratitis

OBJECTIVE To identify clinical and demographic factors associated with a worse visual outcome in Acanthamoeba keratitis (AK). DESIGN Retrospective, case control study. PARTICIPANTS A total of 72 eyes of 65 patients with AK who were diagnosed at the University of Illinois Eye and Ear Infirmary between May of 2003 and May of 2007 with treatment complete by October of 2007. The first affected eye was analyzed in bilateral disease. METHODS Patient demographic, clinical characteristics, treatment methods, and final visual outcome data were collected through medical record reviews for all patients diagnosed with AK. Cases were defined as patients with AK with a visual outcome worse than 20/25 or those requiring penetrating keratoplasty (PKP). Controls were defined as patients with AK with a visual outcome of 20/25 or better. Logistic regression was used to estimate the odds ratio (OR) identifying prognostic factors associated with a worse visual outcome. MAIN OUTCOME MEASURES Final visual outcome worse than 20/25. RESULTS AK was confirmed through microbiologic evidence in 48 of 65 eyes (73.8%) or with confocal microscopy in 62 of 65 eyes (95.4%). Final visual acuity data were available in 61 of 65 eyes (93.8%); of these 61 eyes, 40 (65.6%) achieved a final visual acuity of 20/25 or better. In multivariable analysis, deep stromal involvement or the presence of a ring infiltrate at presentation was independently associated with worse visual outcomes (OR, 10.27; 95% confidence interval [CI], 2.91-36.17). Symptom duration before diagnosis was statistically predictive of disease stage at presentation (OR, 4.43; 95% CI, 0.99-19.83; multivariable analysis) but not final visual outcome (OR, 2.55; 95% CI, 0.83-7.88; univariate analysis). PKP was performed in 11 of 12 eyes with active disease. CONCLUSIONS Corneal disease staging at presentation with slit-lamp examination was highly predictive of worse outcomes, allowing the identification of patients who might benefit from more aggressive medical or surgical intervention. Unlike in previous reports, patient-reported duration of symptoms before treatment was not reliable in predicting the final visual result in our series.

Acanthamoeba keratitis: The Persistence of Cases Following a Multistate Outbreak

Purpose: To describe the trend of Acanthamoeba keratitis case reports following an outbreak and the recall of a multipurpose contact lens disinfection solution. Acanthamoeba keratitis is a serious eye infection caused by the free-living amoeba Acanthamoeba that primarily affects contact lens users. Methods: A convenience sample of 13 ophthalmology centers and laboratories in the USA, provided annual numbers of Acanthamoeba keratitis cases diagnosed between 1999–2009 and monthly numbers of cases diagnosed between 2007–2009. Data on ophthalmic preparations of anti-Acanthamoeba therapies were collected from a national compounding pharmacy. Results: Data from sentinel site ophthalmology centers and laboratories revealed that the yearly number of cases gradually increased from 22 in 1999 to 43 in 2003, with a marked increase beginning in 2004 (93 cases) that continued through 2007 (170 cases; p < 0.0001). The outbreak identified from these sentinel sites resulted in the recall of a contact lens disinfecting solution. There was a statistically significant (p ≤ 0.0001) decrease in monthly cases reported from 28 cases in June 2007 (following the recall) to seven cases in June 2008, followed by an increase (p = 0.0004) in reported cases thereafter; cases have remained higher than pre-outbreak levels. A similar trend was seen in prescriptions for Acanthamoeba keratitis chemotherapy. Cases were significantly more likely to be reported during summer than during other seasons. Conclusion: The persistently elevated number of reported cases supports the need to understand the risk factors and environmental exposures associated with Acanthamoeba keratitis. Further prevention efforts are needed to reduce the number of cases occurring among contact lens wearers.

Gender and glaucoma: what we know and what we need to know

Purpose of review With growing aging populations and an increase in cases of glaucoma and glaucoma blindness worldwide, aging populations are particularly at higher risk of glaucoma and glaucoma blindness. Awareness of the gender differences might increase attention toward populations at risk. Recent findings Women not only outlive men, but also outnumber men in glaucoma cases worldwide. Women are at higher risks for angle closure glaucoma, but there is no clear gender predilection for open angle glaucoma. Of interest, there is some evidence suggesting that female sex hormones might be protective of the optic nerve. In addition, it is hypothesized that decreased estrogen exposure is associated with increased risk for open angle glaucoma, yet population-based studies present inconsistent results. Presently, there is insufficient evidence to support hormonal replacement therapy use in glaucoma prevention. In addition, it appears that women carry a larger burden of glaucoma blindness due to longevity and disadvantages in socioeconomic/health beliefs. Summary Current evidence suggests that older women are at risk for glaucoma and glaucoma blindness. Further interdisciplinary research involving investigators, specialized in glaucoma, womens health and health disparities, will lead to better understanding of gender health disparities in glaucoma and better targeting populations at risk.

Microbial keratitis and the role of rub and rinsing.

Recent outbreaks of microbial keratitis in contact lens wearers have involved various pathogens, including Acanthamoeba and Fusarium species. Specific reasons for the marked increase in microbial keratitis, particularly those involving species typically rarely involved in contact lens infection, remain unknown. Possible contributing factors include inadequacies of various multipurpose solutions against certain pathogens; inadequate lens care hygiene, including elimination of the digital rubbing step; poor contact lens storage case hygiene; and the introduction of new soft contact lens materials that may promote adherence of certain pathogens, particularly when a digital rubbing step is eliminated. Although there is some conflict of opinion in the literature regarding the necessity for a mechanical rub during lens cleaning and disinfection, growing evidence supports the reestablishment of a digital rub component to multipurpose solution lens care systems. This article reviews the literature on whether such a process should be recommended to contact lens wearers.

Prediagnosis Food Patterns Are Associated with Length of Survival from Epithelial Ovarian Cancer

BACKGROUND Dietary factors have been the focus of many studies on the etiology of ovarian cancer and may potentially affect survival. Indeed, three recent studies outside the United States have suggested that diet plays a role in ovarian cancer survival. OBJECTIVE The study purpose was to evaluate the hypothesis that women diagnosed with ovarian cancer whose reported prediagnosis food patterns more closely reflect recommendations for optimal health experience a survival advantage compared with those reporting poorer diets. DESIGN A longitudinal follow-up study design was used to examine prediagnosis usual diet effects on survival among 341 Cook County, Illinois, residents diagnosed with epithelial ovarian cancer during 1994-1998. These women participated in a previous case-control study where diet was assessed using a validated food frequency questionnaire. This diet information was categorized utilizing the Dietary Guidelines for Americans 2005. Deaths through 2005 were ascertained using a national death index search. STATISTICAL ANALYSIS Hazard ratios (HR) and 95% confidence intervals (CI) adjusting for important covariables were obtained from proportional hazards regression models to evaluate diet effects on survival from ovarian cancer. RESULTS Comparisons of high to low food group or subgroup intakes demonstrated statistically significant prediagnosis food pattern associations with survival time. Longer survival was associated with total fruits and vegetables (HR 0.61, 95% CI 0.38 to 0.98, P for trend=0.10) and vegetables separately (HR 0.66, 95% CI 0.43 to 1.01, P for trend <0.05). Subgroup analyses showed only yellow and cruciferous vegetables to significantly favor survival. Conversely, a survival disadvantage was shown for meats, not generally recommended (HR 2.28, 95% CI 1.34 to 3.89, P for trend <0.01), and specifically the red and cured/processed meats subgroups. An increased HR was also observed for the milk (all types) subgroup (HR 2.15, 95% CI 1.20 to 3.84, P for trend <0.05). CONCLUSIONS Prediagnosis adherence to diets that reflect recommendations for optimal nutrition and cancer prevention may have benefits that continue even after an ovarian cancer diagnosis.

Successful Treatment of Chronic Stromal Acanthamoeba Keratitis with Oral Voriconazole Monotherapy

Purpose: To describe the treatment of chronic stromal Acanthamoeba keratitis (AK) with oral voriconazole monotherapy. Methods: All cases of chronic stromal AK recalcitrant to traditional therapy subsequently treated with systemic voriconazole seen at the University of Illinois Eye and Ear Infirmary between June 2003 and July 2009 were reviewed for clinical presentation, clinical course, and outcome. Results: Three eyes of 2 patients were identified with culture-confirmed chronic stromal AK unresponsive to traditional antiacanthamoebal therapies, requiring topical corticosteroids to maintain corneal clarity. Oral voriconazole 200 mg twice daily achieved a rapid but transient reduction of inflammation and elimination of corticosteroid dependency but, in both patients, recrudesced approximately 6 weeks after its discontinuation. Subsequent repeated and/or extended use of oral voriconazole alone resulted in complete resolution ranging from 7 to 11 months off all medications with final best-corrected visual acuity ranging from 20/20 to 20/25. Conclusions: Recalcitrant chronic Acanthamoeba stromal keratitis was successfully treated with extended systemic voriconazole administration with good preservation of vision. The clinical resolution of chronic stromal keratitis in our 2 cases suggests that voriconazole may have a larger role in the treatment of AK.