Why is blinking useful

Not only does this keep the eye from drying out , it also brushes away any tiny particles of dust or dirt that can irritate the eyes and interfere with vision. Excess tears and contaminants drain out through the tear ducts into the nasal passages the reason we get runny noses when we cry!

Over time, that can add up to problems like eye strain and dry eye. Try these blinking exercises:. It is important to be sure that your blink is complete and therefore effective. So, then how can you, the newly reformed blinker, know you are doing it correctly? As you blink, the eyelashes on the upper eyelid will gently almost like a feather touch brush the finger when your eye is completely closed.

It irritates and rubs, but this will pass as good blinking-habits begin to settle in and you begin to feel the difference. Blink … to improve eye comfort! Find out the important science and art of blinking. Blink … to improve eye comfort Blinking cleans the ocular surface of debris and flushes fresh tears over the ocular surface.

Blinking plays an important role in the maintenance of the integrity of the ocular surface because it contributes to the maintenance of ocular surface humidity and favours tear drainage, with expression and dispersion of lipids from meibomian glands.

Reflex and voluntarily controlled blinking are the antithesis of spontaneous blinking but being able to confidently eliminate reflex and voluntary influences on BRs may sometimes not be possible. The rate and degree of tear film evaporation and cooling, or extent of tear film break up TFBU and the associated threshold level for increased osmolarity and dry eye symptom influence on BR, do not appear to be known. For example, threshold levels for symptoms due to hyperosmolarity to stimulate reflex blinking may vary with ocular surface sensitivity and the area of any TFBU for example.

Under most normal-range circumstances and conditions, BRs not only vary according to a wide variety of such factors but also in response to the methods used to measure them. The characteristics of the blink prior to a scan, and any effect it has on tear meniscus volume is uncertain and, as a result, repeated scans involving voluntary blinks may not represent normal-range values. Examples of instructions provided during clinical and experimental studies of tear functions which appear likely to induce voluntary blinking or other form of departure from normal-range spontaneous blink behaviour.

Compared to conditions for SBRs, other characteristics of blinks may vary widely under voluntary control. Accordingly, voluntary control could be invasive with respect to normal-range spontaneous blink performance; perhaps especially when effort is made to be sure that a full blink is achieved. For example, voluntary blinks may be more forceful than spontaneous blinks and so more likely to promote lipid secretion and increase tear layer thickness and tear meniscus volume.

Voluntary blinks involving greater force could also promote faster tear drainage or create tear surface irregularities. The evidence that BR increases as a function of time on task is compelling but apart from the effects of fatigue, for example, other environmental variables influencing BR include the complexity and associated acuity demands of concurrent visual activity as well as cognitive factors.

BR inhibition during visual tasks has been assumed to preserve input information processing, thus reflecting attentional engagement. Blink efficiency is a measure of the ocular surface protective functions of blinking and is determined by the degree that blinking supports tear functions and so contributes to the health of the ocular surface.

For example, both incomplete blinking and low rates of complete blinking reduce blink efficiency. Spontaneous blink efficiency is commonly assessed by only the measurement of BR, 13,14,17,18 but several other features of blink behaviour appear likely to also contribute to blink efficiency.

Variations in interblink intervals and different forms of incomplete blinking such as variations in blink amplitude or degree of closure , the frequency of partial closures such as twitch blinks involving a very minor aborted degree of closure, flurries which are a series of rapidly repeated twitches, as well as differences in the speed of closure and opening phases for example, 19,20 Variation in interblink intervals may be an indication of changing cognitive processing demands during assessment of BRs.

Knowledge about the control of spontaneous blinking is incomplete 3 with little known about its neural basis. In this way the findings are more likely to have relevance to typical levels of blink efficiency for example.

Similarly, the influence of an experimental intervention on blink activity would ideally be measured against normal-range baseline spontaneous blink performance. For example, assessment of tear film break up time TFBUT following voluntary complete blinking appears likely to thicken tear layers and give findings which are not representative of TFBUT during normal-range spontaneous blink activity.

PubMed searches 17th March using the terms spontaneous blink, voluntary blink, and reflex blink yielded , , and potentially useful publications respectively.

Selections of those which were found to be the most relevant and representative of a balanced account of this topic, as well as some selected reports referenced in those publications, were included in this review. Spontaneous blinks are entirely sub-cortical while voluntary blinks are preceded by pre-motor cortical readiness. The neural pathways involved in ocular surface controls over reflex blinking arise in ocular surface sensory input through the trigeminal nerve that projects to the motor neuron of the seventh cranial nerve.

The relationship between pneumatic stimulation and BR was linear suggesting a linear dose-related response relationship between ocular surface input and blinking. The input for triggering ocular surface-stimulated blinks depends on the integrity of the surface nerves. For the 37 who showed a reduction, the mean reduction in BR was It remains possible that increased BRs due to age-related DED could sometimes be moderated by concurrent reduced corneal sensitivity.

The possibility that any sensory message sent by ocular surface cold receptors during evaporation also contributes to the modulation of blinking, is a functional alternative that deserves experimental scrutiny. Such peripheral controls could occur in the absence of any apparent stimulus and could be independent of any central control mechanism. However, increased BR in DED 4,5 may be due to faster evaporation and an associated more rapid rate of tear cooling and osmolarity elevation with resulting greater stimulation of the ocular surface.

Drew reported that BR varied inversely with task difficulty for all subjects that were studied. For individual subjects, BRs are specific to the circumstances under which they are measured and their individual responses to them. For example, the BR for The conditions for resting were not specified in that study. The level of rest achieved may also vary with, for example, uncontrolled influences from visual activity and levels of body comfort.

Conditions such as subjects being completely rested before and during assessment and freedom from emotional stress, such as measurement-related apprehension, 31 may be important. For example, ideally subjects would be unaware that they were being filmed or videotaped during a study of blink behaviour 32 so that any related apprehension, anticipatory thoughts or other potential influences on BR, such as voluntary control of blinking, are avoided.

To the extent that spontaneous blinks occur in the absence of any apparent stimulus, 3 specification of measurement conditions would better inform baseline BR findings and their relationship to spontaneous-range BRs.

For example, estimates of BR by observation during a biomicroscopic examination, which includes a potentially uncomfortable unnatural posture and mental state as well as abnormal lighting conditions, appear unlikely to be relevant to most real-world conditions. Cruz and co-authors reviewed BR assessment methods which included procedures such as lever arms being attached to the lid to detect lid motion, electrooculography, electromyography, wearing lid movement detecting spectacles as well as evaluation of high-speed videotapes.

Dopamine is a hormone functioning as a neurotransmitter in several distinct systems within the brain. Blinks are only an indirect measure of dopamine level which appears to have an important role in cognitive control 34 which, in turn, has a reciprocal influence on BR. For example, difficulty seeing may cause frustration and an associated emotional response. Manipulation and monitoring of affective state are far from simple processes 36 and so appear to be outside the scope of attempts to control affective state during routine BR measurements.

For example, cognitive tasks given to subjects such as counting or detecting particular features in a target display may create confusion, frustration or even reward and satisfaction and might be best avoided during blink behaviour assessment. Ideally BR would be measured under conditions of a state of stable dopamine activity and neutral affect with the avoidance of assessment conditions which could increase apprehension for example.

It is possible that a neutral affective state with minimal cognitive loading may be approached during measurements of SBR by presenting subjects with a meaningless and visually undemanding colour kaleidoscopic film target which undergoes constant colour and pattern changes, as is described further below.

Al-Abdulmunem measured BR by direct observation and secretly counting of blinks for subjects who were attending a lecture. After subjects were informed that their voluntary blinking was going to be assessed and were asked to blink as normally as possible, Kwon and co-authors videotaped their blink behaviour. However, blink performance is commonly assessed by only measuring BR 1,14,16 although incomplete blinking can be another major factor in relation to blink efficiency.

Similarly, there are multiple potential influences on blinking which are altered with voluntary control, when BR, blink completeness, interval rate and regularity as well as force of closure may vary from those features which occur during spontaneous blinking.

In the same manner, operational memory and visual imagination may share components with the visual perceptual systems, and inhibition of blinking may be involved in the protection of these vulnerable processes. Apart from neutral ambient conditions to limit reflex blinking, another important factor determining the validity of blink assessment findings might be that the subject is unaware of their blink performance being assessed.

For example, sham advice that pupil reactions are being monitored could be helpful in avoiding awareness of blink behaviour. Ideally subjects would also not even be aware that they are being videotaped for example.

Such conditions could provide an indication of a baseline SBR against which other influences on blink efficiency might be more usefully compared. Assessment of SBR provides only a limited indication of blink efficiency. Ideally assessment of features of blink behaviour other than BR, such as the frequency and amplitude of incomplete blinking as well as the degree of variation in interblink intervals, which may also have a profound impact on blink efficiency, could also be achieved.

However, to the extent that such detailed analysis appears to be dependent on evaluation of videotape records, it does not appear to be suitable for clinical application. Lack of repeatability in clinical evaluations of tear functions 9 may at least partly be due to variable influences from blinking prior to or during those evaluations.

Providing subjects with the visual task of watching a kaleidoscopic colour pattern video on a television monitor during blink behaviour evaluation might create a minimally cognitive demand with neutral emotional content and influence on central dopamine activity.

For example, this type of task might not have a significant potential to provide a rewarding or emotional experience that could contribute to dopamine activity. Because the kaleidoscopic pattern changes are continuous, rather than periodic, there appears to be less chance that any associated recurring influences on blink regulation would occur with this type of target. The kaleidoscopic target also places low demand on visual clarity because the pattern and colour changes are still evident when blurred.

Normal-range symptom free spontaneous blink rates are more likely to be assessed in a comfortable ambient environment without subject awareness that blink behaviour is being assessed so that voluntary blinking is not involved.

Blink behaviour in such clinical or experimental conditions could provide a reference baseline performance against which the influence of particular interventions could be assessed. For example, any influences on blink behaviour due to symptoms of ocular discomfort, contact lens wear or treatment for dry eye disease may be detected.

Individuals who spend a lot of time on the computer or reading a lot tend to blink less often than they should. Therefore, if your eyes feel dry and irritated when using the computer or reading, then look away and do the following blinking exercises. Blinking Exercises for Dry and Irritated Eyes:. Besides keeping your eyes lubricated, the tear film also: Helps form an almost perfectly smooth front optical surface on the cornea helping light to focus properly.

Washes away debris. Transfers oxygen from the atmosphere to the cornea, since the cornea lacks blood vessels to deliver it directly. Prevents infection due to presence of lysozyme and other antibacterial enzymes. Squeeze your facial muscles around your eyes for three to five seconds.