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Measurement of ocular surface protection under natural blink conditions.

Abelson R, Lane KJ, Angjeli E, Johnston P, Ousler G, Montgomery D - Clin Ophthalmol (2011)

Bottom Line: The traditional methodology (Forced-Stare [FS]) measures TFBUT and IBI separately.TFBUT (P = 0.034) and BUA/IBI (P = 0.001) were able to distinguish the treatment effect of artificial tears in dry-eye subjects.The VCMA methodology provides a clinically relevant analysis of tear film stability measured in the context of a natural blink pattern.

View Article: PubMed Central - PubMed

Affiliation: Arizona State University, Tempe, AZ, USA. rabelson@sdcclinical.com

ABSTRACT

Purpose: To evaluate a new method of measuring ocular exposure in the context of a natural blink pattern through analysis of the variables tear film breakup time (TFBUT), interblink interval (IBI), and tear film breakup area (BUA).

Methods: The traditional methodology (Forced-Stare [FS]) measures TFBUT and IBI separately. TFBUT is measured under forced-stare conditions by an examiner using a stopwatch, while IBI is measured as the subject watches television. The new methodology (video capture manual analysis [VCMA]) involves retrospective analysis of video data of fluorescein-stained eyes taken through a slit lamp while the subject watches television, and provides TFBUT and BUA for each IBI during the 1-minute video under natural blink conditions. The FS and VCMA methods were directly compared in the same set of dry-eye subjects. The VCMA method was evaluated for the ability to discriminate between dry-eye subjects and normal subjects. The VCMA method was further evaluated in the dry eye subjects for the ability to detect a treatment effect before, and 10 minutes after, bilateral instillation of an artificial tear solution.

Results: Ten normal subjects and 17 dry-eye subjects were studied. In the dry-eye subjects, the two methods differed with respect to mean TFBUTs (5.82 seconds, FS; 3.98 seconds, VCMA; P = 0.002). The FS variables alone (TFBUT, IBI) were not able to successfully distinguish between the dry-eye and normal subjects, whereas the additional VCMA variables, both derived and observed (BUA, BUA/IBI, breakup rate), were able to successfully distinguish between the dry-eye and normal subjects in a statistically significant fashion. TFBUT (P = 0.034) and BUA/IBI (P = 0.001) were able to distinguish the treatment effect of artificial tears in dry-eye subjects.

Conclusion: The VCMA methodology provides a clinically relevant analysis of tear film stability measured in the context of a natural blink pattern.

No MeSH data available.


Related in: MedlinePlus

The parameter BUA/IBI represents the fraction of the corneal surface that is at risk (exposed); the units are % corneal surface exposed/second. The BUA/IBI data are represented for normal subjects (circles) and dry-eye subjects (crosses).Abbreviations: BUA, breakup area; IBI, interblink interval.
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f6-opth-5-1349: The parameter BUA/IBI represents the fraction of the corneal surface that is at risk (exposed); the units are % corneal surface exposed/second. The BUA/IBI data are represented for normal subjects (circles) and dry-eye subjects (crosses).Abbreviations: BUA, breakup area; IBI, interblink interval.

Mentions: Groups were compared with respect to two new derived outcomes: BUA/IBI and rate of increase in BUA. BUA/IBI (in units of % cornea exposed/second) represents the fraction of corneal surface at risk or exposed. For the dry-eye and normal groups, BUA/IBI means were 3.70 and 0.45, respectively, for a ratio of 8.22 (P < 0.001). Figure 6 shows the relationship between BUA and IBI. Values for normal subjects clustered in the center of the IBI axis, while dry eye subjects were distributed across a wider range of IBI values and displayed elevated BUA values. For the dry-eye and normal groups, the mean rate of increase in BUA was 7.67 and 2.37, respectively, for a ratio of 3.24 (P = 0.001).


Measurement of ocular surface protection under natural blink conditions.

Abelson R, Lane KJ, Angjeli E, Johnston P, Ousler G, Montgomery D - Clin Ophthalmol (2011)

The parameter BUA/IBI represents the fraction of the corneal surface that is at risk (exposed); the units are % corneal surface exposed/second. The BUA/IBI data are represented for normal subjects (circles) and dry-eye subjects (crosses).Abbreviations: BUA, breakup area; IBI, interblink interval.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3198408&req=5

f6-opth-5-1349: The parameter BUA/IBI represents the fraction of the corneal surface that is at risk (exposed); the units are % corneal surface exposed/second. The BUA/IBI data are represented for normal subjects (circles) and dry-eye subjects (crosses).Abbreviations: BUA, breakup area; IBI, interblink interval.
Mentions: Groups were compared with respect to two new derived outcomes: BUA/IBI and rate of increase in BUA. BUA/IBI (in units of % cornea exposed/second) represents the fraction of corneal surface at risk or exposed. For the dry-eye and normal groups, BUA/IBI means were 3.70 and 0.45, respectively, for a ratio of 8.22 (P < 0.001). Figure 6 shows the relationship between BUA and IBI. Values for normal subjects clustered in the center of the IBI axis, while dry eye subjects were distributed across a wider range of IBI values and displayed elevated BUA values. For the dry-eye and normal groups, the mean rate of increase in BUA was 7.67 and 2.37, respectively, for a ratio of 3.24 (P = 0.001).

Bottom Line: The traditional methodology (Forced-Stare [FS]) measures TFBUT and IBI separately.TFBUT (P = 0.034) and BUA/IBI (P = 0.001) were able to distinguish the treatment effect of artificial tears in dry-eye subjects.The VCMA methodology provides a clinically relevant analysis of tear film stability measured in the context of a natural blink pattern.

View Article: PubMed Central - PubMed

Affiliation: Arizona State University, Tempe, AZ, USA. rabelson@sdcclinical.com

ABSTRACT

Purpose: To evaluate a new method of measuring ocular exposure in the context of a natural blink pattern through analysis of the variables tear film breakup time (TFBUT), interblink interval (IBI), and tear film breakup area (BUA).

Methods: The traditional methodology (Forced-Stare [FS]) measures TFBUT and IBI separately. TFBUT is measured under forced-stare conditions by an examiner using a stopwatch, while IBI is measured as the subject watches television. The new methodology (video capture manual analysis [VCMA]) involves retrospective analysis of video data of fluorescein-stained eyes taken through a slit lamp while the subject watches television, and provides TFBUT and BUA for each IBI during the 1-minute video under natural blink conditions. The FS and VCMA methods were directly compared in the same set of dry-eye subjects. The VCMA method was evaluated for the ability to discriminate between dry-eye subjects and normal subjects. The VCMA method was further evaluated in the dry eye subjects for the ability to detect a treatment effect before, and 10 minutes after, bilateral instillation of an artificial tear solution.

Results: Ten normal subjects and 17 dry-eye subjects were studied. In the dry-eye subjects, the two methods differed with respect to mean TFBUTs (5.82 seconds, FS; 3.98 seconds, VCMA; P = 0.002). The FS variables alone (TFBUT, IBI) were not able to successfully distinguish between the dry-eye and normal subjects, whereas the additional VCMA variables, both derived and observed (BUA, BUA/IBI, breakup rate), were able to successfully distinguish between the dry-eye and normal subjects in a statistically significant fashion. TFBUT (P = 0.034) and BUA/IBI (P = 0.001) were able to distinguish the treatment effect of artificial tears in dry-eye subjects.

Conclusion: The VCMA methodology provides a clinically relevant analysis of tear film stability measured in the context of a natural blink pattern.

No MeSH data available.


Related in: MedlinePlus