TEARS: ARE THEY IMPORTANT?
Dry eye is a really common condition troubling more than five million Americans. A lot of individuals suffer from dry eyes without recognizing the issue. For many decades it was neglected and also was sort of a trash bin medical diagnosis. Even medical doctors were not comfortable in managing it. The majority of prescribed over-the-counter drops which provided temporary alleviation did not relieve the problem. Short-term procedures like taking the red out gave birth to a whole industry without relieving the condition. It is only in the last few years that there has been development in the management of dry eyes. Technological innovations have produced new diagnostic treatment methods. Today, the management of dry eyes is a multibillion-dollar industry. For your information, dry eye is not one problem but multiple diseases put together under one term, as there was no genuine treatment available until a few years back.
The reason dry eyes have sparked such a big interest in the market is due to the realization of the importance of tears. Tears are necessary for the functioning and health of the eye. Lasik triggers dry eyes and consequently, patients, especially over forty may notice a progression of dry eye. Tears are essential for sharp and clear vision This has been brought into focus with presbyopic implants, where dry eyes can play mayhem with the outcome. That is why patients with severe dry eyes like those suffering from Sjogren’s syndrome are not good candidates for presbyopic implants. Tears also carry lysozymes which fight microbes so a drop in tear production can lead to vulnerability to infections.
Importance of Tears
Nutrition: Tears wash the cornea and also the conjunctiva tissue lining the eye and also the eyelids. In the rest of the body, vessels, and cells of blood offer nourishment and protection. Tears take up this role in the eyes, as the presence of vessels would obscure vision.
Vision: The air-tear interface is where the tears covering the cornea can be found in contact with the air in the atmosphere. At this point of contact, the light changes direction so that it can be more focused by the natural lens
Lubrication: The tears develop a thin interface between the cornea and also the eyelids to prevent injury to the cornea.
Protection: The lysozymes attack microorganisms which might try to enter the body through the eyes.
Allergen removal: Every day a lot of dirt and allergens reach our eyes. The tear film entraps them as well as sends them away into the nose and also beyond.
Composition of Tears
The three main components of the tear film are Lipid (or the fatty part), Aqueous (or watery part), and Mucin (the rubbery component). These 3 parts interact with each other in a complicated, physical interaction to produce the tear film. The ratio is as crucial as the quantity.
The watery element is created by the primary lacrimal gland as well as some assistant or accessory lacrimal glands located in the eyelids. The lipid part is from the meibomian glands which lie in the cartilage material of the eyelid and also open up near the origin of the lashes. Mucin is produced by the little glands called goblet cells, located in the conjunctiva, cornea, and also lacrimal gland. Oil floats on water and consequently the lipid and aqueous layer cannot blend. The mucin layer helps the oily layer to blend with the watery layer. Each part plays a specific role and together, their performance is exponential.
There are also minerals, lysozymes, and antibodies. Minerals are essential for the nourishment of the cornea. Lysozymes as well as antibodies are the natural defense reaction of the eye. The proportion, as well as interaction of these 3 elements, are as vital as the total volume.
The tears are spread out throughout the front surface of the eye by the blinking action of the eyelids. The eyelids blink about 16 times per minute. The lower lid holds the tear reservoir. With each blink, the eyelid muscles pump liquid out of various glands, helps blend them and also cause circulation. The top lid layers the cornea with a thin layer of the tear film by its windshield wiper action. In a couple of seconds, this film breaks up, to be restored with the following blink.
Production and drainage
The tears are produced by the lacrimal gland located on the top outer part of the upper eyelid. They flow throughout the eyeball to the minute openings in the internal part of the lids. They are joined on this journey by other components secreted from the glands in the lid margin. The direction of tear flow is due to gravity and also the shape of the eye. It is aided by the pumping force produced when eyelids blink. They then flow down the special tubes to the nose, which in turn is connected to the mouth. That is why when you put drops in the eye you might get strange taste sensations in your mouth.
Definition of Dry Eye
According to the Definition and Category Subcommittee of the International Dry Eye Workshop, “Dry eye is a multifactorial illness of the ocular surface characterized by a loss of homeostasis of the tear film, and accompanied by eye symptoms, in which tear film instability and hyperosmolarity, ocular surface inflammation and damage, as well as neurosensory irregularities, play etiological roles.” In easier terms, dry eye can be defined as when the number of tears in the eye is not enough to execute the functions credited to tears. Vision is affected because the light is unable to refract at the tear cornea junction. There is a delicate balance between the number of tears created, the amount which evaporates into the environment, and also the quantity which is drained through special tubes into the nose. Whenever there is decreased production of tears, increased evaporation or drainage, or a mix of these, the balance is upset and results in dry eyes.
Symptoms of Dry Eye
Usual symptoms of dry eye can be quickly identified once we have recognized the significance of the tear film. Tears play the duty of blood vessels and blood parts, in addition to a lot more. If tears are deficient, the lubrication outcome is lost. With each blink, lids scrape the cornea and conjunctiva damaging the surface tissue. These cells are abandoned and also scrub against the membrane layers generating the feeling of grittiness. There is additionally release of histamines which causes burning, itching, discomfort, and light sensitivity. Air, as well as atmospheric temperature level, stimulate the exposed corneal nerves, creating reflex tearing or watering and pain. Many people question how they can have dry eyes if their eyes are watering. There is 2 type of tearing – basal as well as a reflex. Basic tearing is continuous tear production, regardless of the weather conditions. This production is what’s truly essential for the nourishment and functioning of the eyes. Reflex tearing is generated in response to exterior stimulations and is more to wash away allergens.
The lids attempt to revert the situation by blinking frequently. This can materialize as heavy eyelids as well as result in tiredness. As you may have understood, poor tear film can cause blurs in vision, such as blurriness or rise and falling vision, interfering with reading, computer vision, seeing television, driving, or playing video games. When tears reduce, nourishment to the cornea and also conjunctiva is endangered, causing reflex mechanisms. Capillaries dilate and grow larger to bring nutrition and therefore redness is caused by the red blood in the vessels.
When an individual dream, there is rapid eye movement sleep, hence that phase of sleep is termed as REM sleep. In an individual with dry eyes, that suggests there is even more friction between the cornea, conjunctiva, and also eyelids. The resultant excess watering overnight can dry up to cause the release or perhaps matting of the eyelids.
Survey taking is an art. In the developing area of dry eye management, it is important to detect the proper symptoms. To reduce confusion in terminology and avoid memory lapses, various sets of questionnaires have been developed. They document a person’s subjective dry eye experiences as well as symptoms to transform them into a more unbiased and reproducible data set, which can be compared with others or oneself over time. There are many sets of questionnaires to assess dry eye patients, however, one of the most preferred are the National Eye Institute Visual Feature Questionnaire-25 and the Eye Surface Illness Index.
National Eye Institute Visual Function Questionnaire-25 (NEI-VFQ25)
National Eye Institute developed this 25-item survey to evaluate the irritation from dry eyes as well as document their result on activities of daily living as well as the health-related lifestyle. The questionnaire evaluates general wellness, general vision, a problem with near vision, trouble with distance vision, limitations in social function as a result of the vision, role limitations because of vision, dependency on others as a result of the vision, mental health symptoms due to vision, future assumptions for vision, driving issues, as well as pain and as discomfort around the eyes. Zero is the lowest rating while a hundred is the greatest.
Fig. 1: Closeup of irritated, infected, red, bloodshot eyes
We have seen in the definition that the different sources of dry eye disease lead to tearing film instability, hyperosmolarity, ocular surface inflammation, and damage. It would certainly be prudent to determine these various components to detect dry eye disease.
Tear Film Safety is identified by the following techniques:
Fluorescein TBUT, or Tear Break Up Time: Fluorescein color is instilled in the eye and the person is seated at the slit lamp. The patient is asked to blink and the cornea is observed under the cobalt blue light, which highlights the fluorescein. The moment from when the patient blinks till seeing a spot of the cornea that is no more covered with fluorescein-colored tears is counted in seconds. This is the tear break-up time. A TBUT of more than 8-10 seconds is generally considered standard, whereas under 5 seconds indicates dry eyes.
Non-Invasive TBUT (NITBUT): An image is projected on the cornea and changes are observed in a computer software. Computer software gauges the time to distortion in particular sections of the image.
Ocular Surface Staining
The very same fluorescein color made use of for TBUT is generally applied to spot abnormal or missing epithelial tissue. Under the cobalt blue light, spaces in epithelium show up bright green. Lissamine green and Rose bengal are 2 other dyes that spot harmed cells on the conjunctiva. Lissamine green is less hazardous and also better endured than Rose bengal.
Tear Quantity Assessment
Schirmer’s Test: This uncomfortable test is little used nowadays. A tiny paper strip is placed over the temporal one-third of the lower lid margin before any kind of drops is instilled. After 5 minutes the size of the strip that is damp is measured. This provides reflex tearing. The examination is once again done with anesthetic drops having numbed the eye. This is the basal secretion. Less than 10mm of tear production in 5 minutes, or a significant distinction between 2 eyes, is symptomatic of dry eye.
Tear Meniscus Assessment: Fluorescein dye under the cobalt blue filter can likewise identify the tear meniscus. The height above the lower lid can be measured and relevant inferences drawn. Anterior section OCT can likewise be utilized to measure the tear meniscus height.
Tear Osmolarity: This pain-free examination utilizes a card installed on a tool as well as put over the lower tear meniscus. It can even be used in severely dry eyes as it requires less than 100 nanolitres of tears. Osmolarity < 300 mOsm/L in both eyes and a difference between eyes of < 8 mOsm/L are considered normal.
Matrix Metalloproteinase-9 Test: The tears of patients with a dry eye where their ocular surface barrier function has been compromised have elevated matrix metalloproteinases (MMP). This shows anti-inflammatory treatment may be beneficial. Allergic conjunctivitis and infection may generate a false positive.
Lactoferrin Test: The protein lactoferrin, generated by the acinar cells of the lacrimal gland, has antimicrobial as well as anti-inflammatory properties. Dry eye due to reduced aqueous tear production has a lower concentration of lactoferrin.
Meibography: Digital imaging making use of black-and-white photography, infrared electronic camera, or near-infrared charge-coupled device (CCD) camera of a brightened everted eyelid can describe the silhouette of the meibomian gland. Computer software can do a quantitative analysis of the morphology as well as the structure of meibomian glands.
Interferometry: Lipiview utilizes interferometry and can be used to determine the thickness of the lipid layer.
The Sjo ® Test: In the Sjo test, performed to identify Sjogren’s syndrome, a finger prick sample of blood fills a specimen filter paper to detect 4 SS antibodies (anti-SS-A/Ro, anti-SS-B/La, rheumatoid factor [RF], as well as antinuclear antibody [ANA] together with 3 unique, proprietary early biomarkers, antibodies to SP-1, PSP, and CA-6. Anti-SSA antibody is the only serological marker for Sjogren’s Disorder.
Causes of dry eyes
Allow us to consider an example of a pool, where we desire an optimum degree of water to be constantly present so we can swim comfortably. The inlet faucet produces water at a predetermined rate and the water drainage controls the departure of water from the swimming pool. Additionally, there is dissipation from the surface area of the pool. In hot, dry weather conditions, there will be increased evaporation. While on rainy days the water dissipating into the environment will certainly be markedly less. The level of water may lower in times of dry spells when there is a limitation on the water supply. Ultimately, if there is a leak in the pool there will be greater loss causing reduced water level.
Classification of Etiology of DEDD (Dry Eye Disease)
– Atrophy of tear-producing cells
– Hormonal agent imbalance associated with aging
– A thyroid eye disease
– Diabetes mellitus
– Vitamin A deficiency (unusual in the United States)
– Inflammation – Allergic Reactions, Eyelid swelling (blepharitis), Inflammatory eye problems, including Herpes virus infections as well as uveitis/ iritis
– Suppression by medicines – Medication/supplement usage, including psychiatric medicines, OTC cold medications, antihistamines, beta-blockers, pain relievers, sleeping pills, diuretics, Hormonal substitutes, as well as oral contraceptive pills
– Congenital lack of lacrimal gland
– Surgical excision of tear creating glands
– Post refractive surgical treatment (LASIK or PRK) – dry eye may usually last three to six months, or longer
– Eye surgery of many types, especially lid surgery such as chalazion removal
– Contact lens usage
– Sjogren’s disorder (completely dry mucous membrane layers throughout the body)
– Other autoimmune disorders consisting of Lupus and/or Rheumatoid Joint Inflammation
– Chemical watering/ injuries to the eyes
– Warm in a cold climate
– Outdoors exposure to the sun
– Environmental (dirty, windy, hot/dry)
– Irregular blinking or Poor Blinking, Associated with staring at a computer or video displays
– Lid growths
– Exposure keratitis, in which the eyelids do not close completely during sleep, such as lagophthalmos
– Neurologic problems, consisting of stroke, Bell’s palsy, Parkinson’s, trigeminal nerve disease
If the tear punctum is too large then tears may flow down fast. Rarely, there can be an anatomic variance, and also the tear duct is duplicated. This can again result in an increased flow.
The volume is excellent yet there is a mismatch between the oily and water layers. This is the most challenging issue to resolve.
Treatment of dry eyes
Once a clinician recognizes the cause of the dry eye, it becomes relatively much easier to treat the dryness. The older shotgun method of throwing artificial tears at everyone benefited some but did not treat the cause, and also caused harm in a few. Considering that we have been so thorough in identifying dry eye disease, our treatment methods will be based on that.
There are some general lifestyle changes all people can make before resorting to medications. Eating healthy and balanced green veggies with a lot of water consumption is a great first step. Protecting eyes from smoke, dirt, wind, and sunlight with a good set of sunglasses, especially wraparound types is one more easy choice. A large brim cap or hat can increase protection from these elements.
Exercising regularly, specifically in the fresh air, and also lowering stress and anxiety through meditation will certainly help in reducing systemic disease and also medications required to regulate them. Correct sleeping habits, along with restricting screen time on computers, television as well as phones will also help. Adhere to the 20/20/2 rule – every 20 minutes look away from your book or screen for 20 secs and blink 2 times.
Stay clear of sitting in front of a fan or air conditioning system. While driving, have the windows up and point the a/c vents away from your eyes. A humidifier at work as well as while sleeping will dampen the air. Simple humidifiers increase the dampness in dry areas and are a more natural and useful way to keep eyes moist. Get enough sleep – about 7 to 8 hours a night.
Foods rich in omega-3 fats are of value in improving tear film. Flaxseeds or flaxseed oil, salmon, and sardines have high omega 3 material. They are additionally readily available as supplements, also in artificial tears.
Blepharitis, or lid margin inflammation, which advances to non-infectious inflammation of the eyelids called a chalazion, or even infection of the eyelid called a hordeolum, can be dealt with by a basic warm compress and also lid scrubs. A clean washcloth soaked in cozy (not hot) water is applied over the shut eyelids for a few minutes. This might be repeated 2 or 3 times.
The heat enables the oily gland secretions to thaw. A thermal pulsation device is a costly approach to accomplish the same objective. Lid scrubs, which are created for eyes can then be delicately scrubbed along the base of the eyelashes as well as the lid margin itself to loosen any particles and open the pores.
Lid scrubs are also offered as a foam which can be applied at the time of taking a shower. Lid scrubs are superior to another method where child shampoo is massaged with fingers or Q pointers on the base of the lashes.
Drops to minimize eyelid inflammation. Anti-biotics may be utilized alone to take on any kind of infection that exists. They are typically integrated with steroids momentarily to reduce swelling which might be protecting against various glands from carrying out their work.
Systemic Prescription antibiotics to improve the quality of tears. An antibiotic known as Doxycycline comes with a twin effect. It battles any type of infection present along with making gland secretions a lot more fluid. It is administered in a reduced dosage over many weeks. It may trigger some bowel disturbances; however, it is otherwise well-tolerated. It must not be given to pregnant women nor teenagers, as it can trigger staining of teeth and bones.
Eyedrops to control inflammation of lacrimal glands. In the last few years, there has been commercial advancement of immune-suppressing medicine cyclosporine (Restasis or Xiidra). This decreases the inflammatory cells in tear glands, especially the lacrimal gland. The reductions of inflammatory cells prompt the lacrimal gland to start once again.
Eye drops made from your blood. They are the last resort when various other treatments fall short. To produce these eye drops, blood is drawn and centrifuged to eliminate red cells. The remaining fluid is combined with a salt solution.
Making use of light therapy and eyelid massage therapy. A technique called intense-pulsed light treatment followed by a massage of the eyelids has been shown to help patients with severe dry eyes.
Acupuncture. Some therapists assert acupuncture treatment can increase tear production.
Artificial Tears – These drops are available with chemicals or without preservatives. Chemicals are added to prevent detonation from outside stimuli. They can therefore be packaged in multi-use bottles which can last weeks. These drops can be made use of one to four times a day. Preservatives are hazardous to the epithelium as well as any type of additional rise in frequency of usage can damage the epithelial cells. Non-preservative eye drops, on the other hand, have no preservatives and also have a limited-service life. They are packaged as single-use clear vials. They can be put as frequently as every half hour, unlike artificial tears which contain preservatives or chemicals.
Drops vs. Ointments – Lubricating eye ointments are much better than drops. They stick and layer the surface of the eyes. They provide longer relief from dry eyes. The eye lotion is thicker and can make vision blurry. They are as a consequence best-made use of in a small quantity at bedtime. In the morning, water from the shower can be made to fall on the closed eyes to get rid of excess ointment. Ointments are a good choice for those who are too busy to administer eye drops. Eye drops can be used at any time and also will not hinder your vision. This is especially useful for patients who have had recent eye surgery, whose eyelids open during sleep, or patients making use of CPAP machines.
There is an intermediary product, somewhere in between drops and lotions, available called gel drops. These are thicker eye drops which last much longer.
Eye inserts that function like man-made tears – These inserts, made from hydroxypropyl cellulose (Lacrisert), are inserted daily between the lower eyelid and the eyeball. As they liquify, they release elements similar to eye drops.
Drops that take the red out – These temporary options function by restricting the tiny capillaries on the surface of the eye. As we have gone over above, the blood vessels provide nourishment for the eyes and body. By removing this source of nutrition there is more stimulation for capillary production. That means with time these very drops cause increased redness.
Some sunglasses spray moisture at regular intervals. These glasses also obstruct wind or dirt from getting to the eye. Eyeshades for sleeping stop direct exposure as well as dissipation without touching the eye itself. Making use of special contact lenses called scleral contact lenses to safeguard the surface of the eyes by trapping moisture between the cornea and the lens. They keep the severe dry eye bathed in fluid. Castor oil eye drops may increase symptoms by minimizing tear dissipation. This is not a recommended alternative nowadays.