Measurement of ocular surface protection under natural blink conditions

Abelson, Richard; Lane, Keith Jeffrey; Angjeli, Endri; Johnston, Patrick; Ousler, George W; Montgomery, Douglas C.

doi:10.2147/opth.s22017

Cited by 9 publications

(15 citation statements)

References 16 publications

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“…Video capture allows calculation of a mean corneal surface exposure (we abbreviate this as mean break-up area, MBA) as well as additional metrics, such as palpebral fissure width. In an initial paper, we showed that video capture of MBA and blink rates was superior to the combination of forced stare TFBUT and IBI in distinguishing normal subjects from those with signs and symptoms of dry eye 6. In a second paper, we demonstrated that our automated method provided accurate, reliable measures of corneal surface exposure, and again showed that these values could be used to distinguish between normal subjects and subjects with dry eye 7…”

Section: Introductionmentioning

confidence: 82%

“…This is a result of significant strides in ocular surface biology research, and improvements in clinical assessment techniques such as, corneal staining, blink pattern analysis, and various measures of tear film stability 4,5. In two recent papers we described the stepwise development of our improved method of tear film analysis, which we have designated the ocular tear film analysis protocol OPI 2.0 (Ora, Inc. Andover MA, USA; patent pending) system 6,7. This method combines a number of optimized parameters with automated video data capture and analysis, to generate a more objective, quantitative measure of tear film dynamics.…”

Section: Introductionmentioning

confidence: 99%

“…For example, it was found that reduction and standardization of the quantity of fluorescein used, led to a shift of the reference values for TFBUT (to a mean value of 7 seconds for normal subjects, and 2.5 seconds for those with dry eye) 5. Similarly, our goal in developing the OPI 2.0 system was to enhance and streamline dry eye metrics by measuring tear film stability under conditions of natural, rather than forced stare blinking 6,7. Furthermore, by capturing the natural dynamics of the tear film with automated methods, it is possible to expand upon previous studies of the interaction between blinking and tear film behavior 8–13…”

Section: Introductionmentioning

confidence: 99%

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A single-center study evaluating the effect of the controlled adverse environment (CAEsm) model on tear film stability

Abelson¹,

Lane²,

Rodriguez³

et al. 2012

OPTH

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PurposeTo investigate use of an improved ocular tear film analysis protocol (OPI 2.0) in the Controlled Adverse Environment (CAESM) model of dry eye disease, and to examine the utility of new metrics in the identification of subpopulations of dry eye patients.MethodsThirty-three dry eye subjects completed a single-center, single-visit, pilot CAE study. The primary endpoint was mean break-up area (MBA) as assessed by the OPI 2.0 system. Secondary endpoints included corneal fluorescein staining, tear film break-up time, and OPI 2.0 system measurements. Subjects were also asked to rate their ocular discomfort throughout the CAE. Dry eye endpoints were measured at baseline, immediately following a 90-minute CAE exposure, and again 30 minutes after exposure.ResultsThe post-CAE measurements of MBA showed a statistically significant decrease from the baseline measurements. The decrease was relatively specific to those patients with moderate to severe dry eye, as measured by baseline MBA. Secondary endpoints including palpebral fissure size, corneal staining, and redness, also showed significant changes when pre- and post-CAE measurements were compared. A correlation analysis identified specific associations between MBA, blink rate, and palpebral fissure size. Comparison of MBA responses allowed us to identify subpopulations of subjects who exhibited different compensatory mechanisms in response to CAE challenge. Of note, none of the measures of tear film break-up time showed statistically significant changes or correlations in pre-, versus post-CAE measures.ConclusionThis pilot study confirms that the tear film metric MBA can detect changes in the ocular surface induced by a CAE, and that these changes are correlated with other, established measures of dry eye disease. The observed decrease in MBA following CAE exposure demonstrates that compensatory mechanisms are initiated during the CAE exposure, and that this compensation may provide the means to identify and characterize clinically relevant subpopulations of dry eye patients.

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Section: Introductionmentioning

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A single-center study evaluating the effect of the controlled adverse environment (CAEsm) model on tear film stability

Abelson¹,

Lane²,

Rodriguez³

et al. 2012

OPTH

Self Cite

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“…Utilizing this method, the mean breakup area (MBA) and OPI 2.0, defined as MBA/IBI, are calculated and analyzed. Initially, a method of retrospective manual analysis of fluorescein staining video data was utilized with the OPI 2.0 System 13. In this method, which is referred to as video capture with manual analysis (VCMA), a panel of examiners evaluated the integrity of the tear film and determined IBI and TFBUT by manually stopping the video to note and confirm the time stamp, and record the time of each blink and the first appearance of a micelle within each IBI.…”

Section: Introductionmentioning

confidence: 99%

Validation and verification of the OPI 2.0 System

Abelson¹,

Lane²,

Rodriguez³

et al. 2012

OPTH

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PurposeThe Ocular Protection Index (OPI) 2.0 System was developed to evaluate ocular surface protection under a natural blink pattern and normal visual conditions. The OPI 2.0 System implements fully automated software algorithms which provide a real-time measurement of corneal exposure (breakup area) for each interblink interval during a 1-minute video. Utilizing this method, the mean breakup area (MBA) and OPI 2.0 (MBA/interblink interval) were calculated and analyzed. The purpose of this study was to verify and validate the OPI 2.0 System for its ability to distinguish between dry eye and normal subjects, and to accurately identify breakup area.MethodsIn order to verify and validate the OPI 2.0 System, a series of artificial images and a series of still image frames captured during an actual clinical session using fluorescein staining videography were analyzed. Finally, a clinical validation process was completed to determine the effectiveness and clinical relevance of the OPI 2.0 System to differentiate between dry eye and normal subjects.ResultsSoftware analysis verification conducted in a set of artificially constructed images and in actual videos both saw minimal error rates. MBA and OPI 2.0 calculations were able to distinguish between the qualifying eyes of dry eye and normal subjects in a statistically significant fashion (P < 0.001 for both outcomes). As expected, dry eye subjects had a higher MBA and OPI 2.0 than normal subjects (0.232, dry eye; 0.040, normal and 0.039, dry eye; 0.006, normal, respectively). Results for the worst eyes and all qualifying analyses based on staining, forced-stare tear film breakup time, and MBA were numerically similar.ConclusionThe OPI 2.0 System accurately identifies the degree of breakup area on the cornea and represents an efficient, clinically relevant measurement of the pathophysiology of the ocular surface.

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“…Tracking of natural blink patterns on video allows for accurate, noninvasive assessments that can easily be obtained, offering an advantage over more intensive and potentially inaccurate forced stare measures, such as fluorescein staining, mean breakup area, and tear film breakup time, or subjective measures such as symptomatic breakup time and potentially ambiguous ocular discomfort assessments 25,26. We chose documentary viewing as the visual task during our blink experiments because this gave greater repeatability compared with primary gaze, as well as more closely approximating a common everyday activity.…”

Section: Discussionmentioning

confidence: 99%

Investigation of extended blinks and interblink intervals in subjects with and without dry eye

Rodriguez

Ousler²,

Johnston³

et al. 2013

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BackgroundThe purpose of this study was to investigate the occurrence and duration of extended blinks ≥ 70 msec and their associated interblink intervals in normal subjects and in subjects with mild to moderate dry eye.MethodsThis single-center, prospective, double-blind study included 11 subjects with dry eye and eight subjects with normal eyes. Extended blinks were defined as lid closure in at least two successive video frames (≥70 msec). Digital video imaging of each subject’s eyes was recorded while the subject viewed a 10-minute documentary. The subjects did not know that blink was the outcome being measured. Following capture, the videos were manually analyzed in a masked fashion for the occurrence of extended blinks. The length of the interblink interval (ie, time between blinks) before and after these extended blinks (the interblink interval ratio) was calculated, as well as differences in lid contact times.ResultsThe dry eye group had a median extended blink duration which was 2.53 times longer than that of the normal group. For subjects with dry eye, interblink intervals post-extended blink were significantly longer than interblink intervals pre-extended blink (P < 0.001). Interblink intervals did not lengthen significantly in normal subjects. In both groups, the duration of the extended blink was significantly (P = 0.001) and positively correlated with interblink interval ratio (post-extended to pre-extended blink interblink interval), such that for each doubling of extended blink duration, the interblink interval ratio increased by 10%. Blinks longer than one second in duration occurred almost exclusively in subjects with dry eye.ConclusionThis study reports three central findings: blink duration tended to be longer in subjects with dry eye; a lengthening of the interblink interval after an extended blink occurred in subjects with dry eye but not in those without dry eye; and a longer blink duration was associated with a significantly increased interblink interval ratio in all subjects.

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Measurement of ocular surface protection under natural blink conditions

Cited by 9 publications

References 16 publications

A single-center study evaluating the effect of the controlled adverse environment (CAEsm) model on tear film stability

A single-center study evaluating the effect of the controlled adverse environment (CAEsm) model on tear film stability

Validation and verification of the OPI 2.0 System

Investigation of extended blinks and interblink intervals in subjects with and without dry eye

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