What causes Dry Eye Syndrome?
Dry eye syndrome can occur when basal tear production decreases, tear evaporation increases, or tear composition is imbalanced. The lipid layer overlays a mucoaqueous layer. TFOS DEWS II recommends using one of two validated questionnaires for evaluating the symptoms component of a dry eye diagnosis: the Ocular Surface Disease Index
Women are more likely to develop the condition due to hormonal changes during pregnancy and after menopause. This syndrome is evidenced in up to 50 per cent of the population and can occur at any age. The basis for all inflammatory, painful of feverish reactions is usually an irritation of or damage to single cells. This can be triggered by mechanical, thermal or chemical stimuli. Also by medications such as (cold and allergy) antihistamines, decongestants, blood pressure, diuretics, beta-blockers, sleeping pills, anxiety medications, hormone replacement therapy,rocutane. Dry eye syndrome through extended computer and phone use is effecting younger adults now in addition to the typical age-related groups.
DRY EYE SYNDROME EXAMINATION
The OCULUS Keratograph 5M is not only an advanced corneal topographer useful in contact lens design but also in dry eye diagnosis. Its unique features and camera allow examining the meibomian glands, non-invasive tear film break-up time and the tear meniscus height measurement and evaluating the lipid layer.
Corneal topography produces a detailed, visual description of the shape and power of the cornea. This type of analysis of the corneal surface, enables diagnosis and management of various eye conditions.
Keratoconjunctivitis sicca is chronic, bilateral desiccation of the conjunctiva and cornea due to an inadequate tear film.
The blink rate can point to some tear anomalies. The oily lipid layer can be graded by interferometry, the aqueous layer by tear meniscus height and the mucin layer by the non-invasive tear break up time. Even chronic cases may require topical corticosteroids, tetracyclines, and cyclosporine A as anti-inflammatory therapy. A band of superior lid frictional damage stained by lissamine green sometimes can be evidence of lid wiper epitheliopathy a hallmark of dry eye.
Dye eye treatment
Natural treatments include:
Bilberry, paprika, Chamomile.
Omega 3 supplements containing retinols can improve skin by shrinking the oil-producing glands without diminishing the oil-producing meibomian glands of the eyelids required to stop evaporation. Warm and cold compresses and humidifiers can be considered -the tear film has a direct influence on focusing and aberrations.
Dry eye and Blephasteam
Blephasteam melts via comfortable, effective and safe moist heat technology the commonly blocked meibomian glands, which cannot be safely achieved with conventional heat packs.
However, omega 3 supplements greater than 1200mg/day and blinking exercises are becoming increasingly important. Humidifiers can be beneficial, as can eyelid massage but need to minimise pressure on the globe; hence the merit of blephasteam.
After 10 minutes of treatment where vision is not adversely affected, the blocked essential evaporation reducing lipid oils are naturally released through normal blinking. Blephasteam heats your eyelids to 40°C, which has been demonstrated to be sufficient to melt the obstructing meibum with no risk to your eyes and eyelids.
Combined with the treatment’s length, this temperature and moisture level is safe and comfortable for use. A stye is a red and painful lump on the eyelid that occurs when a tiny gland on the edge of the eyelid becomes infected or inflamed, and heat can certainly help.
Blephasteam has shown tear film evaporation reduction. It is better than a warm compress. Serial IPL can restore the MG morphology, restore some function and reverse anatomical changes in the rosacea and the abnormal blood vessels, which release pro-inflammatory agents.
Those inflammatory agents propagate to the eyelids via the orbital vasculature. IPL targets chromophores and destroys abnormal blood vessels, removing a significant source of inflammation. By contrast, Lipiflow(vectored thermal pulsation (VTPTM) technology) heats and massages for a continuous 12min. Serial Blephasteams every week for 4-5 weeks can achieve a similar outcome.
Blephasteam is applied before Meibomian Gland Expression as it provides optimal conditions (such as consistent temperature and duration of heat) to prepare the glands and oils for unblocking. The safety and efficacy of Blephasteam have been evaluated in many clinical studies at this temperature. Blephasteam is a natural therapy and can be supplemented with Blephex debridement to increase tear breakup time.
Meibomian Gland Dysfunction MGD
Ocular Surface Society [TFOS] DEWS II (International Dry Eye Workshop ) referenced more than 1,000 publications for an evidence-based review of eye therapies.
The ocular surface disease index OSDI confirms the possibility of DED requiring diagnostic tests of non-invasive tear break-up time, osmolarity and ocular surface staining to determine if cause predominantly evaporative or aqueous deficiency.
In this eye disease, reduced tear secretion leads to inflammation and eye nerve damage which can be assessed.
We can avoid people making the mistake of self-diagnosing eg eye drops for their allergens, or swollen eyes with cucumber slices or tea bags or use the wrong eye ointments based on their waking symptoms. Warm compresses often preceded by cold can reduce inflammation and help lipid flow.
Tears are complex, being hundreds of different protein, fatty oil, water, mucus types
In the first 6 postnatal months, the tear film’s lipid layer is much thicker than in adults. The NIBUT in newborns is prolonged compared with adult values. This thick lipid layer in infants provides the stability that may help prevent the thin aqueous layer from evaporating.
Eyelid warming is crucial as it melts the solid or blocked lipids into a more viscous oil again. This allows the natural oils in your tear film to flow freely again and form the tears’ oily layer, which reduces evaporation. In Meibomian Gland Dysfunction, the oily secretions become more substantial, ultimately blocking the glands. This can lead to atrophy of the glands and produce the symptoms of this eye syndrome.
If acne rosacea is likely to be a factor in your blepharitis, an oral antibiotic called doxycycline may be prescribed for several months to improve your meibomian gland function from the inside out.
A nutritional supplement containing omega 3 oils and micro-nutrients may also be prescribed.
Treatment can take weeks to several months. During this time, you will be advised not to wear contact lenses and refrain from using eye makeup.
Meibomian Gland Grading
Fully atrophied or blocked
Congealed or semi-solid discharge
Coloured liquid discharge
Clear liquid oil discharge
The Ocular Surface Disease Index and scoring algorithm include 12 questions, which are subdivided into three groups. Namely visual symptoms of DES, the ocular symptoms while watching television or reading a book, and ocular symptoms induced by environmental factors.
The OSDI questionnaire is graded on a scale from 0 to 4, where 0 indicates none of the time; 1, some of the time; 2, half of the time; 3, most of the time; 4, all of the time. The total score of OSDI is calculated on the basis of the following formula: OSDI = [(sum of scores for all questions answered) × 100] / [(total number of questions answered) × 4].
Although there is no internationally accepted criterion for the diagnosis of DES, the OSDI is a standardised instrument to evaluate symptoms. It can easily be performed and used to support the diagnosis of DES.
The correct frequency of blinking milks your meibomian gland oils, which are very temperature sensitive.
Specific heat is defined by the amount of heat needed to raise 1 gram of a substance 1 degree Celsius (°C). Water has a high specific heat capacity. It takes higher energy to increase the temperature. The moist heat transfer within the blephasteam to the eyelids a lower temperature than otherwise be needed to melt the obstructed meibomian oil can be applied. This difference is achieved by the latent heat condensing as water from vapour releasing heat energy.
A reduced frequency of blinking, which can happen quickly, deteriorates the tear film leading in severe cases to such conditions as keratoconjunctivitis sicca. A quality tear film can reduce optical aberrations as light can scatter from the highly powered corneal surface. In computer vision syndrome, the blink rate is decreased rather than complete and frequent blinks.
Air conditioning, low humidity, can exacerbate the condition, as can preservatives in some overused OTC drops, eyelid makeup, or even refractive surgery. Other options include topical steroids, punctal plugs, Suitable artificial tears -mimicking standard mucin layer, blinking efficiency exercises.
Also, Surgery/laser to lids or eye surfaces, wrap sunglasses and minimising exposure to heaters /airconditioning. Windy, smoky, or low humidity environments increase tear evaporation.
Treatment can include probiotics, autologous serum eye drops, face and sun creams containing tea tree oil, eyelid hygiene for rows of tiny oil-secreting glands.
Pain from excessive evaporation can be caused by tear hyperosmolarity, loss of lubrication, inflammatory mediators and neurosensory factors, while visual symptoms arise from tear and ocular surface irregularity.
Also advancing age and conditions such as Rosacea, Blepharitis, Sjögren’s syndrome, Lupus, Scleroderma, Rheumatoid Arthritis, Diabetes, Thyroid disorders, Parkinson’s Disease and Vitamin A deficiency, Eyelid health, e.g. bacterial films, oil gland congestion.
Meibomian gland dysfunction
Certain medications such as antihistamines and HRT
Allergies (contact lens solution, makeup, certain eye drops or ointments)
Seborrheic dermatitis (dandruff of the scalp and eyebrows)
Changes in oestrogen levels eg menopause, pregnancy.
|Common signs and symptoms include: |
Redness of the eyes and eyelids. Watery sticky eyes
Flaking or crusting of skin on the eyelids on waking
Crusting at the eyelid margins (base of the eyelashes), generally worse on waking
Gritty sensation of the eye or foreign-body sensation
Foreign body sensation
Excessive or frothy tears
Sensitivity to light
BLEPHEX debridement is the removal of the biofilm and debris from the eyelids. This can effectively offer relief while removing excess oils and debris that may cause symptoms. Demodex parasite mites (that live on humans) can be found on the eyelashes. If mite populations increase they can cause itching or inflammation
The meibomian glands – situated along the eyelids can be gently compressed to examine their discharge. Healthy meibomian glands produce a thin, oily secretion, whereas dysfunctioning glands will have a thicker, waxy secretion, or, in worse cases, no secretion at all due to complete blockage
CORNEAL DYSTROPHY, Dry eye, HYLO PRODUCTS, eyelid hygiene, MANUKA HONEY, I-LID 'N'LASH,OCUSOFT, LACRITEC,I-CHEK
Persistent epithelial defects are prolonged healing of corneal wounds. Neurotrophic or recurrent keratitis or ulcers are significant healing difficulties caused by loss of corneal sensitivity, potentially resulting in corneal perforation.
Cacicol drops can help with corneal wound healing.
Apart from observing with high in office magnification, using an illuminated self-examination mirror such as Ichek help identify the debris and crusting you may have on your eyelids and eyelashes before effectively cleaning and gently scrubbing.
OCuSOFT Lid Scrub Original is recommended for routine daily eyelid hygiene. At the same time, OCuSOFT Lid Scrub PLUS is an extra-strength, “leave-on” ( can be used twice a day for several hours and rinsed off) formula recommended for moderate to severe conditions. To use pre Moistened new Pad, fold over your index finger onto the closed eye and gently scrub over your eyelid using side-to-side strokes with the index finger for approximately 30 seconds.
Regular use of OCuSOFT eyelid cleansers to gently remove oil and debris from your eyelids will help control these symptoms. To reduce ocular surface inflammation, anti-inflammatory therapies such as oral doxycycline may be prescribed. Many people routinely use often expired Visine or “clear eyes ” that constrict the eye’s superficial blood vessels. Your eyes can develop a tolerance to the whitening effect of these drops, and even greater redness (called rebound hyperemia) can indeed occur.
How to use I-Lid’N Lash and I-Lid’N Lash Plus
1. Apply a moist, warm compress to the eyelid to loosen encrusted debris and secretions Gently rub eyelid and eyelash roots with the pre-moistened pad in a circular motion
2. Do not rinse. Any remaining product will continue to disinfect and hydrate the skin. Repeat as needed for the second eye using a clean wipe
Leptospermum sp honey (Manuka) can aid in this condition and meibomian gland dysfunction, Blepharitis Sore, irritated eyes, and eyelids. The only adverse effects noted with Optimel Manuka+ Eye Drops in the eye are stinging and redness. While the conventional treatment of eye hygiene and lubricants also significantly improved symptoms, the long utilised honey products improved the condition more.
Punctal plugs can be used without issues commonly, but with optimel (Manuka Honey) the sting may be prolonged (and occasional allergy/sensitivity to honey ( Patients with marked blepharitis may not be the best candidates for punctal plugs due to the risk of creating a sequestered environment from which tears cannot easily drain.)
Optimel gel once a day (sometimes x2) for nearly all patients in the target group. Usually, 2-3 mths duration as an increasing reaction to Optimel can occur past three mths use but can be quite variable. Warm compresses followed by lid massage or lid scrub, then Optimel is the standard procedure, mainly when reactions to cyclosporine occur. A course of steroids until the eye settles somewhat sometimes is undertaken before Optimel.
Many dietary influences can bear on conditions such as dry eye disease.
The antioxidant resveratrol (found in chocolate, grapes, peanuts, mulberries and red wine ) can regenerate human corneal epithelial cells
Hylo products are for mild, severe or persistent cases or post-surgery use, being preservative-free eye drops in a unique bottle. They are citrate buffered – completely phosphate-free.
They precisely deliver at least 300 sterile drops per pack through the patented COMOD multi-dose application system at 60% less cost per drop. Whilst honey products have an antibacterial effect, lowering Staphylococcus epidermis counts, there is a short sting on the installation of drops during the day or gel before bed though good eyelid hygiene, clean eyes and eyelid margins is good initial therapy. Honey products can supplement dry eye therapy, as can anti-inflammatory Hycor 1% ointment to the eyelid rim. Honey Products do have an antibacterial effect, as they lower the Staphylococcus epidermis count, there is a short sting on the installation of drops during the day or gel before bed. Good eyelid hygiene is the aim. Honey products can supplement dry eye therapy, as can anti-inflammatory Hycor 1% ointment to the eyelid rim. DRYEYE FORTE is manufactured in Australia and audited for compliance by the Therapeutic Goods Administration (TGA). If you are already eating a healthy diet and still experiencing dry eye symptoms, that may suggest your diet is not providing enough of the nutrients recommended to help relieve dry eye symptoms.
DEMODEX treatment routine needs to be convenient enough to be continued for life to avoid relapses as blepharitis is often a chronic condition.
OCUSOFT allows you to employ your daily regime by cleansing your eyelids and eyelashes by
• Ocusoft lid scrub swabstix
• OCuSOFT Oust Demodex Cleanser Extra Strength Foam
• Blephex debridement can be used for more severe cases or by lid spud as dry eye can be worse in the morning as the lids have been closed at night and often toxic meibum is along the lid margins, which needs to be flushed away and tear equilibrium restored. To use the pre-lathered Ocusoft foam formula, make sure your hands are clean pump the Lid Scrub foam onto a clean, lint-free washcloth or fingertip.
LACRITEC is a formulation that works from the inside out to provide continuous dry eye relief.
•Lacritec delivers a proprietary blend of omega fatty acids sourced from Flax Seed, Fish Oil, and Borage Oil.
•Australian developed, patented formulation works to support a healthy tear film, thereby increasing Tear Film Breakup Time and reduce inflammation in tear glands.
•Much more potent than flaxseed oil or fish oil alone, it also provides the unique omega fatty acid, GLA, from Borage Oil that cannot be easily obtained from diet independently.
I-LID ’N LASH
The convenient, one-step lid and lash cleanser to disinfect and hydrate
Formulated with sodium hyaluronate, I-LID ‘N LASH cleans and removes ocular debris while hydrating sensitive skin.
Daily use helps to maintain lid and lash health for patients with dry eyes, sensitive skin or Meibomian Gland Dysfunction.
I-LID ’N LASH PRO
This is a stronger hydrating cleansing gel with 20% Tea Tree Oil, an essential oil derived mainly from Melaleuca alternifolia, to disinfect lids and lashes requiring advanced cleansing.
DRYeye Forte features GLA from plant-based Borage Oil, as well as high quality, mercury-tested fish oil. When fish omegas EPA and DHA team up with GLA, inflammation is reduced in a complementary fashion.
DRYeye Forte is a blend of concentrated omega-3 EPA & DHA from Fish Oil, omega-6 GLA from Borage Oil, Vitamin D3 and antioxidants that increase tear production and quality can reduce inflammation.
Ingredients include mercury tested, sustainably sourced omega-3 fish oil, providing high strength EPA & DHA. Some essential fatty acids are not easily obtained from a typical diet, such as gamma-Linolenic acid GLA from Borage Oil
Combined with other essential nutrients such as anti-inflammatory Vitamin D and the rich antioxidants of mixed tocopherols, DRYeye Forte’s patented formula helps fight inflammation and support the three layers of the tear film.
Results are typically experienced within 6 to 8 weeks. The dosage may vary according to your weight and the severity of your dry eye symptoms. As symptoms recede, dosage may then be reduced to a maintenance level.
DRYeye Forte is a patented oral formulation in a soft gel capsule that works from the inside out to target the dry eye’s root causes.
DRYeye Forte may be combined with artificial tears, drop or sprays. Because it is an oral formulation that targets dry eye syndrome from within, it works by a complementary mode of action to these topical products.
Certain individuals can be intolerant of individual ingredients. High doses of Omega-3, Omega-6, and Vitamin E may increase bleeding risk if you are taking blood-thinning medications.
It is generally recommended that you take your DRYeye Forte capsules with or after food in the morning.
DRY EYE FORTE DOSAGE Three caps per day for the first two packets (6 weeks), then reduce dose to 2 per day for the 3rd packet and then usually 1 per day for the 4th packet onwards yields the best therapeutic result for the patient.
ADVANCED DRY EYE DISEASE TREATMENTS AND REPORTING
Intense pulse light (IPL) of 500nm light in a series of calibrated pulses stimulates the Meibomian glands to return their normal function by closing the blood vessels that secrete inflammatory mediators. The 20-25 glands in both top and bottom lids decline with age. Over 40, we have between 10-12 on each. The Inferior glands tend to dysfunction first, though. The minimum required is 3-4 each lid for comfortable eyes in most people.
In rosacea, abnormal blood vessels release pro-inflammatory agents
Those inflammatory agents propagate to the eyelids via the orbital vasculature.
IPL targets chromophores (the chemical responsible for its colour) and destroys abnormal blood vessels, removing a significant source of inflammation.
Lipiflow treats dry eye symptoms but not the root cause, which in the majority of cases is MGD caused by skin and ocular inflammation. This inflammation or rosacea can be treated quite successfully with IPL therapy. Peer review and clinical studies have some variance in the preferred modality.
IPL reduces inflammation and telangiectatic vessels around the eyelid margins, whereas Lipiflow unblocks meibomian glands.
The lipiscan only images the Meibomian glands, whereas the Lipiview also measures the lipid content in the tear film and shows the quality and the frequency of the blinking pattern.
Large randomised controlled trials are difficult to set up as they are so expensive to run – independent granting agencies don’t tend to fund dry eye research as they devote their attention to more sight or life-threatening disease. The industry is interested in clinical efficacy data for shaping their future direction. Investigator-initiated trials where possible are carried out, but cross comparative studies tend not to occur with potential conflict and perceived bias.
Some IPL manufacturers include
Diamond Q4 (Dermamed)
Other mechanisms in play for IPL :
. Temporary increase of temperature at the eyelids and liquefaction of the meibum
. Reduction of rosacea and turnover of dead skin cells, therefore decreasing the risk of clogging the glands
. Eradication of Demodex mites (which carry B. Oleronius bacteria), thus reduces bacterial load
. IPL increases the expression of anti-inflammatory agents. Rejuvenation of the Meibomian glands by photo modulation
Clinical efficacy can be gleaned by analysing cytokine levels in tears as an inflammatory marker pre/post-IPL.
• All MGD/IPL studies to date use gel.
• Coupling gel aids with the transmission of energy into the skin.
• The first law of photobiology (the Grotthus-Draper law) states that light must be absorbed to produce a chemical or physical change, which results in a biological response.
No gel would result in a lower biological response due to reflection, and reflections have increased the potential for surface skin burns.
Some patient’s quality of life can continue even with high MGD drop out but not generally.
Many studies show a reduction in symptoms and improved meibum quality and gland function for patients suffering from dry eye disease caused by meibomian gland dysfunction treated with intense pulsed light therapy. However, sufficient control populations for comparison are not commonplace, as are evidence-based guidelines.
LipiScan can image both eyes in about a minute, whereas the more thorough LipiView II utilises Dynamic Meibomian Imaging (DMI) to reflect meibomian gland structure distinctively. In addition, the interferometer features patented technology analysing over one billion data points to isolate the lipid layer of the tear film, measuring the thickness to sub-micron levels to evaluate the lipids’ dynamic response to blinking.
IPL is an entirely different mechanism and has additional benefits beyond just heating the Meibum. Photothermolysis of the abnormal vasculature and stimulation of mitochondria put this device as superior arguably.
Rexon-Eye treatment to stimulate metabolism and natural regeneration of cells, by Quantum Molecular Resonance behind a worn mask consists of 4 20 minute treatments, then a 1-week break, often employing Lavender, Sandal, Jasmine, Chamomile aromatherapy.
Cequa (cyclosporin 0.9 mg/mL) is an aqueous immunosuppressant indicated for treating moderate-to-severe dry eye (keratoconjunctivitis sicca). Cequa works by reducing inflammation and increasing tear production so the eyes are better lubricated. One drop is administered twice daily (about 12 hours apart) into each eye. Precautions should be taken when using it in patients who have a potential for eye injury or contamination, patients with infections, severe keratitis and patients who use contact lenses.
Lifitegrast (Xiidra) was approved by the Therapeutic Goods Administration in 2019 for the treatment of moderate-to-severe dry eye disease in adults for whom prior use of artificial tears has not been sufficient. Xiidra eye drops contain lifitegrast 50 ng/ml (5%) solution. One drop of Xiidra is administered to affected eye(s) using a single-use container per administration, twice a day.Contact lenses should be removed prior to administration of Xiidra and may be reinserted 15 minutes later. Studies suggest that in moderate-to-severe dry eye disease, lifitegrast improved the dry eye symptoms of itching, foreign body sensation and discomfort by day 42 and often after 2 weeks. Dry eye affects more than seven per cent of the Australian population and is one of the most common reasons for seeking medical eye care
About one in five patients with dry eye are dissatisfied with their overall treatment due to lack of symptom relief and the time taken to relieve symptoms and treatment side-effects. The condition can significantly compromise vision, quality of life and work-related productivity. Symptoms include discomfort, visual disturbance, burning, stinging, grittiness, foreign body sensation, tearing, ocular fatigue, redness, light sensitivity and dryness.
Dry eye is becoming increasingly common, especially in younger people, due to increased digital screen time. Exposure to air conditioning, ceiling fans, and forced-air heating systems in indoor environments can all lower humidity and exacerbate tear evaporation, causing dry eye symptoms.
Report use of eye drops for lubrication or other treatments and medications in case of dry eye side effects.
Report the type of SYMPTOMS you experience and when they occur: e.g. dryness, grittiness, scratchiness, soreness, irritation, burning, watering or eye fatigue. Objective assessment can still be carried out.
Report the FREQUENCY of your symptoms and SEVERITY using a rating system/diary, eg
0 = No Problems
1 = Tolerable – not perfect, but not uncomfortable
2 = Uncomfortable – irritating, but does not interfere with my day
3 = Bothersome – irritating and interferes with my day
4 = Intolerable – unable to perform my daily tasks
Establishing the cause is fundamental. Even a stomach infection can be connected. Eg Helicobacter pylori (Hp) infection associated with dry eyes, glaucoma and other eye diseases has been reported.
1. Non-invasive tear film stability assessment (using reflected mires)
2. Osmolarity testing
3. Fluorescein and lissamine green staining of cornea, conjunctiva and lid margin
Testing for aqueous deficiency
Tear meniscus height (slit lamp estimate)
Phenol red thread (moderately invasive)
Schirmer test (useful when applied without anesthetic only for confirming severe aqueous deficiency, as a highly invasive test)
Tear meniscus height quantified digitally from infrared imaging (IR minimises the risk of reflex tearing)
Testing for evaporative dry eye
1. Lid margin assessment thickening, rounding, notching, telangiectasia, capped orifices
2. Lash assessment for madarosis, poliosis, misdirection, crusting, and cylindrical collarettes
3. Diagnostic gland expression performed digitally to evaluate meibum expressibility and quality
1. Lid margin assessment (as for necessary testing, plus infrared meibography)
2. Lash assessment ( epilation for Demodex evaluation under 100x light microscopy)
3. Diagnostic gland expression for meibum expressibility
4. Lipid layer interferometry
Dry eye diagnosis is based on traditional and emerging technologies such as
• Functional Visual Acuity tests ( quantifies vision quality between blinks as worse in dry eye conditions).
• Tear volume Schirmer test ( application of a filter paper test strip in the inferior temporal conjunctival sac of both eyes- length of the tear wetting is measured in millimetres
• Phenol red thread test( The alkaline pH of the tears causes the dye to turn from yellow to red, and then the length of the tear wetting is measured in millimetres)
• Tear meniscus height measurement by anterior OCT.
• Fluorophotometry ( records the fluorescein concentration of different parts of the eye, including the cornea and vitreous.)
• Tear film stability Invasive Tear Break up time ( The time (in seconds) between a blink and the appearance of a dark spot in the fluorescein is the TBUT) . The Non-invasive tear break up time uses rings captured as they are reflected off the precorneal tear film. The time between the blink and the first sign of ring distortion is the NI-TBUT
• Tear turnover rate/tear clearance Fluorescein clearance, TFI, fluorophotometry (Tear Function Index (TFI) and fluorescein clearance test (FCT) measure tear clearance and are performed by instilling fluorescein and a testing strip in the lower cul-de-sac. Serial measurements are taken, and the amount of residual dye present on a ribbon is compared with a standard colour scale)
• Tear film composition Osmolarity Biomarkers: MMP-9, lysozyme (Specific biomarkers for dry eye may be present in the tear film to aid in diagnosis)
• Corneal evaluation Fluorescein staining Epithelial thickness, confocal microscopy, thermography (infrared measure of the temperature of the cornea normally higher in dry eyes.
• Conjunctival evaluation Lissamine green, rose bengal Biopsy, impression cytology, confocal microscopy ( Confocal microscopy examines the in the epithelial and stromal layers, as well as the corneal nerves in dry eyes)
• Lid evaluation Slit lamp evaluation of lid morphology, expression of meibomian glands,meibomoscopy, blink rate, Meibography,
• Lid wiper epitheliopathy ( alteration of the epithelium of that portion of the marginal conjunctiva that wipes the ocular surface, diagnosed by staining with fluorescein and rose bengal, is a frequent finding with wearers of soft contact lenses.
• Sjögren’s syndrome testing by serological tests, and a combination of signs and symptoms, biopsies.