The Interblink Interval I: The Relationship between Sensation Intensity and Tear Film Disruption

Varikooty, Jalaiah; Simpson, Trefford

doi:10.1167/iovs.08-1843

Cited by 27 publications

(28 citation statements)

References 57 publications

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“…The differences between groups reached statistical significance (Mann-Whitney U test, P < 0.05) for ''irritation'' and ''pricking.'' These results agree with our previous studies, which indicate that TBU in eye opening trials was associated with irritation, stinging, and burning, 15,20,22 but also suggest that diminishing corneal fluorescence over time without TBU is associated with an irritative affective response. The difference in discomfort experienced by subjects in the BU and BUmin groups is illustrated in Figures 2 and 3, which show individual data for the change in discomfort during trials reported by four of the subjects in this study.…”

Section: Resultssupporting

confidence: 93%

“…Both groups showed increasing discomfort as the median PI decreased, but the BUmin group progressed at a slower rate than the BU group. These data strongly support the hypothesis that the rate of increasing discomfort during extended eye opening trials 22 is highly correlated with the rate of diminishing fluorescence, whether associated with TBU or not.…”

Section: Sensory Measuressupporting

confidence: 85%

“…As in previous studies, subjects were asked to keep the tested eye open as long as possible 20,21 while they turned a knob (potentiometer) to indicate the level of discomfort in the tested eye on a 0 to 10 scale (0 ¼ no discomfort and 10 ¼ very uncomfortable). 22 Following each trial, subjects rated their overall discomfort on separate integer scale of 1 (no discomfort) to 10 (very uncomfortable) and then indicated the level of irritation, stinging, burning, pricking, and cooling on visual analogue scales (VAS). The fluorescent tear film was recorded digitally (30 frames/s) using a cobalt blue excitation filter over the light source and a Wratten no.…”

Section: Methodsmentioning

confidence: 99%

“…Previously, we have shown that tear film breakup (TBU) is associated with sensations of burning and stinging and results in increased symptoms of ocular irritation, implying that increased tear film hyperosmolarity or other adverse conditions may occur during TBU, stimulating ocular surface nerves. [20][21][22] In this study, we quantified global thinning and regional TBU by employing a pixel-based analysis of fluorescence and compared the concurrent sensory responses of TBU versus tear thinning during the interblink period. We hypothesize that changes in corneal fluorescence during the interblink period are due tear film thinning and/or TBU, and that both are associated with sensory stimulation to the cornea.…”

mentioning

confidence: 99%

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Quantitative Analysis of Tear Film Fluorescence and Discomfort During Tear Film Instability and Thinning

Begley

Simpson

Liu

et al. 2013

Invest. Ophthalmol. Vis. Sci.

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PURPOSE. The purpose of this study was to test the association between tear film fluorescence changes during tear break-up (TBU) or thinning and the concurrent ocular sensory response.METHODS. Sixteen subjects kept one eye open as long as possible (MBI), indicated their discomfort level continuously, and rated ocular sensations of irritation, stinging, burning, pricking, and cooling using visual analog scales (VAS). Fluorescence of the tear film was quantified by a pixel-based analysis of the median pixel intensity (PI), TBU, and percentage of dark pixels (DarkPix) over time. A cutoff of 5% TBU was used to divide subjects into either break-up (BU) or minimal break-up (BUmin) groups. RESULTS.Tear film fluorescence decreased (median PI) and the percentage of TBU and DarkPix increased in all trials, with the rate significantly greater in the BU than the BUmin group (Mann-Whitney U test, P < 0.05). The rate of increasing discomfort during trials was highly correlated with the rate of decrease in median PI and developing TBU (Spearman's, r ‡ 0.70). Significant correlations were found between corneal fluorescence, MBI, and sensory measures.CONCLUSIONS. Concentration quenching of fluorescein dye with tear film thinning best explains decreasing tear film fluorescence during trials. This was highly correlated with increasing ocular discomfort, suggesting that both tear film thinning and TBU stimulate underlying corneal nerves, although TBU produced more rapid stimulation. Slow increases in tear film hyperosmolarity may cause the gradual increase in discomfort during slow tear film thinning, whereas the sharp increases in discomfort during TBU suggest a more complex stimulus.Keywords: tear film instability, tear film break-up, tear film thinning, evaporation, fluorescein concentration quenching, corneal sensory nerves, nociception D ry eye is a common condition, affecting millions in the United States and elsewhere, 1-5 affecting quality of life, [6][7][8] and potentially engendering high health care costs now and in the future. 9 However, despite its prevalence and impact, the underlying etiology of the condition and the basis of dry eye symptoms remain subject to speculation. 10,11The recent international Dry Eye Workshop report identified the core mechanisms of dry eye as tear film hyperosmolarity and instability, which are thought to generate dry eye symptoms through repeated stress to the ocular surface, inflammation, and activation of corneal sensory nociceptors. 10In support of this hypothesis, tear hyperosmolarity has been shown to stress the surface and trigger ocular surface inflammation, 12,13 and recent reports have associated tear film hyperosmolarity with dry eye symptoms. 14 However, while tear film osmolarity is likely to fluctuate markedly or spike 15 in the interblink interval due to evaporation or other factors, [16][17][18] it cannot be measured directly over the cornea with current techniques of sampling the tears from the inferior meniscus. 19 Thus, changing conditions within the tear film during ins...

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Section: Resultssupporting

confidence: 93%

Section: Sensory Measuressupporting

confidence: 85%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Quantitative Analysis of Tear Film Fluorescence and Discomfort During Tear Film Instability and Thinning

Begley

Simpson

Liu

et al. 2013

Invest. Ophthalmol. Vis. Sci.

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“…16 Blinking is driven to a certain extent by ocular surface stimuli. 17 The nonYsoft lensYwearing cornea, which was exposed during a period of consciously not blinking, was found to become irritated with shorter tear breakup time associated with more rapid rates of increased irritation. 17 Innocuous ''cold'' corneal thermoreceptors are activated by drying of the ocular surface and hyperosmotic solutions, conditions which are consistent with a role in tear production.…”

Section: Causes Of Symptomsmentioning

confidence: 99%

Psychological and Other Mechanisms for End-of-Day Soft Lens Symptoms

McMonnies

2013

Optometry and Vision Science

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Rather than dry eye symptoms, end-of-day discomfort in CL wearers might be more appropriately described as dry lens symptoms. Apart from tear function, lens condition, compliance with lens care instructions, and symptom strength, lens awareness may also be determined by psychological factors such as motivation, high expectations for comfort, and sense of subjective well-being. For example, high levels of comfort experienced on lens insertion may increase expectations of the level of comfort to be experienced at the end of the day. In addition, patient management seems to require a thorough assessment of lens comfort, which may indicate the need to review a patient's understanding of the relation between compliance and other factors, which could influence CL performance negatively. For example, increased use of digital devices, especially in air conditioning, and any associated reduced blink efficiency seem likely to be important contributors to dry lens symptoms.

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Diagnostic Tools

Vasaiwala¹,

Kirk²,

Bouchard³

2021

Blepharitis

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The Interblink Interval I: The Relationship between Sensation Intensity and Tear Film Disruption

Abstract: The method provides novel information about the development of ocular sensation during ocular surface drying. As evidenced by the complex functions required to adequately describe the relationships, tear film drying and ocular surface sensations are associated in complex ways.

Cited by 27 publications

References 57 publications

Quantitative Analysis of Tear Film Fluorescence and Discomfort During Tear Film Instability and Thinning

Quantitative Analysis of Tear Film Fluorescence and Discomfort During Tear Film Instability and Thinning

Psychological and Other Mechanisms for End-of-Day Soft Lens Symptoms

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