Faculty Bibliography

Ultraviolet corneal collagen cross-linking (CXL) has been shown to possibly delay, halt, or even reverse disease progression in keratoconus. Understanding of keratoconic progression in untreated eyes, however, is still incomplete and is hampered by the varying definitions and metrics used to evaluate corneal changes. As a result, the CXL literature varies widely in criteria for progression and parameters for successful outcomes. To date, there have been few long-term, well-controlled clinical trials supporting the efficacy of CXL to prevent progression in keratoconus. Review of our data on keratoconus suggests the course of corneal change is difficult to predict and that many keratoconic eyes appear stable once the eyes begin to exhibit frank changes in corneal curvature typical of keratoconus. Better-defined metrics for progression in keratoconus are needed. Larger, long-term randomized clinical trials may more clearly establish the efficacy and safety of CXL in the management of keratoconus and determine which patients are the best candidates for this procedure.

INTRODUCTION/BACKGROUND:Dry eye disease (DED) is a common, age-related ocular condition that in its mildest forms causes bothersome symptoms of ocular discomfort, fatigue, and visual disturbance that interfere with quality of life and in its more severe forms causes chronic pain and fluctuating vision. Though it is highly prevalent and costs billions of dollars to manage, current treatments have largely been inadequate, making it a frustrating condition, both for physicians and patients alike. AREAS COVERED/METHODS:This article will cover the recently discovered pathophysiology of DED that has prompted investigators to explore new molecules that target the core mechanisms that drive DED. These include anti-inflammatory/immune-modulatory drugs, secretagogues, lubricant, hormones, and autologous serum. Their potential mechanism of action and data from recent trials on efficacy/safety will be reviewed. EXPERT OPINION/CONCLUSIONS:The emerging drugs have a vast range of putative mechanisms of action that may not only provide symptomatic relief but may potentially break the vicious cycle of DED and provide long-lasting cure. Current and future research may change our perspective on DED and redefine its treatment algorithms.

Purpose/Aim: Corneal abrasions and nonhealing corneal epithelial defects are common conditions that cause pain and sometimes are slow to heal. Histatins, a family of histidine-rich peptides, have been implicated in oral and skin epithelial wound healing, and have been shown to be effective in vitro in human corneal epithelial cells. The objective of this study was to test the efficacy of histatin-1 on corneal epithelial wound healing in rabbits.

BACKGROUND:Diagnostic tests for dry eye disease (DED), including ocular surface disease index (OSDI), tear breakup time (TBUT), corneal fluorescein staining, and lissamine staining, have great deal of variability. We investigated whether fluorophotometry correlated with previously established DED diagnostic tests and whether it could serve as a novel objective metric to evaluate DED. METHODS:Dry eye patients who have had established signs or symptoms for at least 6 months were included in this observational study. Normal subjects with no symptoms of dry eyes served as controls. Each eye had a baseline fluorescein scan prior to any fluorescein dye. Fluorescein dye was then placed into both eyes, rinsed with saline solution, and scanned at 5, 10, 15, and 30 min. Patients were administered the following diagnostic tests to correlate with fluorophotometry: OSDI, TBUT, fluorescein, and lissamine. Standard protocols were used. P < 0.05 was considered significant. RESULTS:Fifty eyes from 25 patients (DED = 22 eyes, 11 patients; Normal = 28 eyes, 14 patients) were included. Baseline scans of the dry eye and control groups did not show any statistical difference (p = 0.84). Fluorescein concentration of DED and normal patients showed statistical significance at all time intervals (p < 10(-5), 0.001, 0.002, 0.049 for 5, 10, 15, & 30 min respectively). Fluorophotometry values converged towards baseline as time elapsed, but both groups were still statistically different at 30 min (p < 0.01). We used four fluorophotometry scoring methods and correlated them with OSDI, TBUT, fluorescein, and lissamine along with adjusted and aggregate scores. The four scoring schemes did not show any significant correlations with the other tests, except for correlations seen with lissamine and 10 (p = 0.045, 0.034) and 15 min (p = 0.013, 0.012), and with aggregate scores and 15 min (p = 0.042, 0.017). CONCLUSIONS:Fluorophotometry generally did not correlate with any other DED tests, even though it showed capability of differentiating between DED and normal eyes up to 30 min after fluorescein dye instillation. There may be an aspect of DED that is missed in the current regimen of DED tests and only captured with fluorophotometry. Adding fluorophotometry may be useful in screening, diagnosing, and monitoring patients with DED.

Abstract Purpose: The purpose of this study was to examine the inherent precision and accuracy of TearLab Osmolarity System using salt solutions, including solutions of very high osmolarity (>360 mOsm/L). MATERIALS AND METHODS: Ten salt solutions with osmolarity between 286 mOsm/L and 394 mOsm/L (increments of 12 mOsm/L) plus an additional solution of 400 mOsm/L were tested twice on both the TearLab osmometer and a freezing point depression osmometer. For precision, we compared the two repeated osmolarity measurements of 11 solutions obtained from TearLab. For accuracy, we compared the averaged osmolarity measurements obtained from TearLab to those from the freezing point depression osmometer. For both precision and accuracy, Bland-Altman test of agreement was used. RESULTS: For precision, the upper 95% limit of agreement was 4.7 mOsm/L, and the lower 95% limit of agreement was -7.1 mOsm/L. The repeatability coefficient was 5.9 mOsm/L. For accuracy, the upper 95% limit of agreement was 4.8 mOsm/L and the lower 95% limit of agreement was -5.3 mOsm/L. CONCLUSIONS: The present study is the first study to demonstrate that the TearLab in situ osmometer can precisely and accurately measure osmolarity of salt solutions, including those with very high osmolarity. Future studies to evaluate the precision and the accuracy of the machine in measuring complex fluids, such as tears, need to be done, and the clinical significance of measuring tear osmolarity in patients needs to be further determined.

PURPOSE/OBJECTIVE:To provide standard operating procedures (SOPs) for measuring tear inflammatory cytokine concentrations and to validate the resulting profile as a minimally invasive objective metric and biomarker of ocular surface inflammation for use in multicenter clinical trials on dry eye disease (DED). METHODS:Standard operating procedures were established and then validated with cytokine standards, quality controls, and masked tear samples collected from local and distant clinical sites. The concentrations of the inflammatory cytokines in tears were quantified using a high-sensitivity human cytokine multiplex kit. RESULTS:A panel of inflammatory cytokines was initially investigated, from which four key inflammatory cytokines (IL-1β, IL-6, INF-γ, and TNF-α) were chosen. Results with cytokine standards statistically satisfied the manufacturer's quality control criteria. Results with pooled tear samples were highly reproducible and reliable with tear volumes ranging from 4 to 10 μL. Incorporation of the SOPs into clinical trials was subsequently validated. Tear samples were collected at a distant clinical site, stored, and shipped to our Biomarker Laboratory, where a masked analysis of the four tear cytokines was successfully performed. Tear samples were also collected from a feasibility study on DED. Inflammatory cytokine concentrations were decreased in tears of subjects who received anti-inflammatory treatment. CONCLUSIONS:Standard operating procedures for human tear cytokine assessment suitable for multicenter clinical trials were established. Tear cytokine profiling using these SOPs may provide objective metrics useful for diagnosing, classifying, and analyzing treatment efficacy in inflammatory conditions of the ocular surface, which may further elucidate the mechanisms involved in the pathogenesis of ocular surface disease.

PURPOSE/OBJECTIVE:To evaluate pill counts and red blood cell (RBC) membrane fatty acid profiles as measures of compliance with oral omega3 polyunsaturated fatty acids (ω3 PUFAs) and to compare the two techniques. METHODS:Sixteen dry eye disease subjects were given oral ω3 PUFA or placebo for 3 months. Compliance was measured by pill counts and blood tests at baseline and 3 months. The Wilcoxon signed-rank tests and rank-sum tests were used to compare changes from baseline and the difference between the two groups; Spearman correlation coefficients were used to assess the relationship of pill counts to changes in blood FAs. RESULTS:Pill counts for the ω3 (n=7) and placebo (n=9) groups showed a mean consumption of 4.39 and 4.76 pills per day, respectively. In the ω3 group, the median change from baseline was +1.46% for eicosapentaenoic acid (EPA) (P=0.03), +1.49% for docosahexaenoic acid (DHA) (P=0.08), and -1.91% for arachidonic acids (AA) (P=0.02). In the placebo group, median changes in all measured FAs were small and not statistically significant. The difference in change in FA levels between the two groups was significantly greater for EPA (P=0.01) and AA (P=0.04). The correlations between pill counts and changes in EPA (r=0.36, P=0.43) and DHA (r=0.17, P=0.70) were not strong. CONCLUSIONS:RBC FA analysis can be used to measure compliance in the active group and also monitor the placebo group for nonstudy ω3 intake. Low correlation of pill counts with blood levels suggests that pill counts alone may be inaccurate and should be replaced or supplemented with objective measures.

There are currently no validated minimally invasive objective metrics for the classification and evaluation of ocular surface diseases and/or for evaluating treatment efficacy. We thus sought to establish a standardized methodology for determining the relative amount of the inflammatory biomarker HLA-DR on the ocular surface and to evaluate the precision, reliability and repeatability of its use for large multicenter clinical trials and translational research studies of ocular surface disease. Multiple studies were conducted to establish a Standard Operating Procedure (SOP) for utilizing HLA-DR expression as a minimally invasive, objective, ocular surface inflammatory biomarker. The established SOPs provide specific guidelines for HLA-DR collection and analysis, in order to incorporate it reliably into multicenter clinical trials and/or translational research. Duplicate cell samples from impression cytology (IC) samples of both normal and dry eye individuals were collected and split to assess repeatability (between the splits and between the duplicate samples). To determine storage capability, one duplicate was stained immediately and the other after 30 days cold storage. To demonstrate the feasibility of the use of the SOP for a multicenter clinical trial, clinicians out-of-state were trained to collect IC samples, and the samples shipped to our Biomarker Laboratory, logged, processed and analyzed. Demonstration of the ability to incorporate of IC into a randomized double masked clinical trial of dry eye disease (DED) was performed. In all cases, processing and analyses were performed by a masked independent observer. The validity/viability of the SOPs was established by demonstrating that: 1) sufficient numbers of cells can be collected via IC; 2) the precision/repeatability of the relative biomarker expression quantified in samples; 3) personnel at distant sites can be taught to collect, store and ship samples successfully; 4) samples can be stored for up to 30 days (refrigeration) before processing without affecting results; 5) IC can be incorporated into a double blind randomized clinical trial (RCT) of DED; and 6) the Biomarker Laboratory can track a large number of masked samples reliably. In conclusion, our standard operating procedure for impression cytology analysis of HLA-DR expression appears to be repeatable and reproducible for use in multicenter clinical trials, providing a minimally invasive objective biomarker of inflammation of the ocular surface.