The tear film function is a much greater player than just wetting the eyes. At every blink a micro layer of it is spread over the cornea which in turn lubricates the surface, supports clear vision, washes out irritants and helps in fighting off infection. Thus a stable tear film is very base for proper tears and eye health. When this protective mechanism breaks down the eyes may report dryness, grittiness, excess watering or temporary blur.
What Is the Tear Film Function?
The tear film which is that which covers the cornea and conjunctiva. Its primary functions are lubrication, optical clarity, protection and maintenance of a healthy ocular surface. Also it’s tear film function reduces friction between the eyes and lids which happens thousands of times each day. The National Eye Institute reports that tears keep the eyes wet and smooth and also play a role in focusing light which comes in. Also tears protect the surface of the eye from dust, dirt and infection.
Understanding the function of tear film also helps explain why seemingly minor tear abnormalities can cause noticeable visual discomfort.
| Tear component | Main source or feature | Main role |
| Lipid or oily component | Meibomian glands | Slows evaporation and improves stability |
| Aqueous or watery component | Lacrimal glands | Moistens, cleans and carries protective substances |
| Mucin component | Ocular surface and goblet cells | Helps tears spread and remain attached to the surface |
How Does the Tear Film Protect Healthy Eyes?
One important tear film function is to present a smooth optical surface over the cornea. Through this surface light enters the eye which in turn heads toward the retina. If at the time of blinking tears do not replenish evenly, light may scatter out of sync and what they often see may fluctuate.
Also a healthy tear film plays a role in washing out small particles and environmental irritants. Vasan eye care see research which reports that tears contain proteins, glycoproteins and other factors which in turn support antimicrobial defense, control of inflammation and surface repair. This relationship between tears and eye health which in part is what also causes persistent tear film issues to in turn affect comfort and visual quality.
The tear film is very thin. In the clinical literature it is reported that the precorneal tear film to be of a thickness of 2 5.5 micrometres which still is a very small scale but within this thin optical layer see great changes between blinks.
What Happens During Every Blink?
Blinking refreshes and distributes tears in the eye. The eyelids spread the tear film, play a role in removing debris and in the release of oils from the meibomian glands. This process which repeats itself during wakeful hours is what maintains tear film function. Vasan Eye Care have detailed out which role does blinking play in eye health which includes the fact that reduced or incomplete blinking does in fact disrupt this process.
Long time periods in front of screens reduces effective blinking. Fans and air conditioners also increase evaporation. While hydration and eye health it should be noted that drinking more water does not in fact treat all tear film disorders.
| Situation | Effect on the tear film | Possible experience |
| Normal complete blinking | Redistributes tears evenly | Comfortable, clearer vision |
| Prolonged screen use | Reduced or incomplete blinking | Dryness, burning or intermittent blur |
| Wind or air conditioning | Faster tear evaporation | Grittiness and irritation |
| Tear-film dysfunction | Unstable surface coating | Watering, discomfort or fluctuating vision |
Why Can Dry Eyes Sometimes Cause Excess Tears?
It may sound contrary but dry eyes do in fact produce what appears to be extra tears. What happens is that an unstable surface which in turn irritates the sensory nerves which in turn cause the lacrimal glands to produce reflex tears. These may in large quantity be produced yet do not correct the base issue of tear film quality.
People asking why tears come from eyes without any reason may in fact have dryness, allergy, irritation, or issues with their eyelids or blocked tear drainages put to them. For good tear film function health vasan eye care counts on a proper play of tear volume, composition, spread and drain. It is also true that tearing does not always indicate well-lubricated or healthy eyes..
What Can Disrupt Tear Film Function?
Ageing, long term use of screens, contact lenses, dry air, smoke and some medications may disrupt tear stability. Meibomian gland dysfunction which reduces the oily component of tears may also cause them to evaporate faster.
Alcohol is also a factor in dehydration and temporary visual changes. In terms of the relationship between alcohol and blurry vision it goes beyond the eye alcohol also plays a role in focus and eye teaming.
Persistent burning, foreign body sensation, redness or fluctuating vision shouldn’t be dismissed as a result of lifestyle. An ophthalmologist can determine what is at the root of the issue which may be related to tear film function, the cornea, eyelids or some other eye condition.
How Can the Tear Film Be Kept Healthy?
Regular full blink cycles, taking visual breaks, and also staying away from air directed at your eyes may support the health of your eyes. Use contact lenses as per professional advice which is especially true when dryness sets in.
Persistent issues of the eye do not improve with repeated self treatment of random lubricating drops. At Vasan Eye Care we have a lot of info on dry eye treatment which details that management should correspond to the cause and type of dryness. Also we have info on what are the common causes of persistent dry eyes and air conditioning related eye irritation which in turn play a role in disturbing tear film function.
When Should Tear or Eye Symptoms Be Checked?
Occasionally mild irritation may present after long screen use or environmental exposure. In the case of constant pain, large redness, light sensitivity, discharge or continuous visual changes a professional assessment is required. Sudden loss of vision, severe eye pain or large eye injury requires prompt medical evaluation. These symptoms should not be put forward that they result from tear film issues alone.
Eye Care at Vasan Eye Care
Vasan Eye Care provides assessment for issues like dryness, watering, irritation and other ocular surface problems. An ophthalmologist will look at the cornea, eyelids and tear film before they determine if in depth testing or treatment is needed. They also do well to understand the role of tears and eye health which in turn will help patients see that comfortable vision is a result of more than just eyesight.
Stable tear film function supports a smooth ocular surface and in turn daily visual quality. It is when symptoms persist or worsen that a visit to the eye doctor is in order instead of more of the same at home treatment.
Frequently Asked Questions
1. What is the main function of the tear film?
The primary tear film function is to maintain a smooth, moist and protected ocular surface. Also tears support vision clarity, they wash out debris, reduce the friction at the time of blinking and they contain elements which protect the eye from microorganisms.
2. Can an unhealthy tear film cause blurry vision?
Yes. An unstable tear film which in turn may produce an irregular optical surface over the cornea. Vision may become temporarily hazy or to fluctuate between blinks. Persistent blur requires evaluation which is true for refractive, corneal, retinal and other conditions that may cause similar symptoms.
3. Are watery eyes a sign of healthy eyes?
Not always. What is true is that for healthy eyes balanced tear production, distribution and drainage is key. Dryness which in turn causes the eye to water, and blocked drainage which in fact may also cause overflow of tears out of the eye which may seem paradoxical at first.
4. How are tears and eye health connected?
Tears and eye health which they do by lubricating the ocular surface, supporting clear vision and in removing irritants. Also they contain bio active substances that play a role in surface defense and repair. Thus persistent tear issues may require an ophthalmic evaluation.
References
- National Eye Institute — How Tears Work
https://www.nei.nih.gov/eye-health-information/healthy-vision/how-eyes-work/how-tears-work - Biological Functions of Tear Film — Experimental Eye Research / PubMed
https://pubmed.ncbi.nlm.nih.gov/32561483/