Differentiating between dry eye and allergic conjunctivitis can be a complicated and frustrating task for many clinicians. Signs and symptoms of both dry eye and allergic conjunctivitis can be subjective and vague, and may appear to overlap. The two conditions, however, do not share the same etiology, and treatment methods are different. Whether bwd individual has dry eye, allergy or a combination of both disorders, understanding the etiology and pathophysiology of each condition is essential for correctly diagnosing and treating patients. Pathophysiology of Dry Eye. Despite the similar symptoms, dry eye and allergy each have a distinctive pathophysiology. Dry eye is caused by tear film instability resulting from insufficient or unhealthy production of one or more tear film components, namely:.
Ocular mucins are found both on the surface of the eye and freely floating in the aqueous.
Underproduction of mucins by goblet cells and conjunctival epithelial cells can affect the ability of the tear film to adhere to the hydrophobic ocular epithelium. The accessory glands are responsible for tear production, while the primary gland is associated with reflex tearing.
Reflex tearing can sometimes be stimulated by the appplication of Schirmer I strips, which are used to measure tear volume. Some physicians believe reflex tears can render unanesthetized Schirmer measurements inaccurate. Fluorophotometry can provide more accurate measurements of tear volume and tear flow; however, it is also more time consuming.
Because these tear film abnormalities could be related to various environmental or biological influences, pinpointing the underlying cause of a patients dry eye symptoms may require a work-up that ranges from an extensive history to laboratory studies. Blinking replenishes and maintains the integrity of the tear film; yet environmental, activity-related, psychological, and physiological factors can alter the blink rate.
When the blink rate is diminished, the tear film can become instable. Rapid tear film break-up caused by tear film instability can lead to ocular surface exposure, especially when combined with abnormal blink rates.
When tear film break-up occurs before a blink can replenish the tear film, some portion of the ocular surface will be exposed to the air. Over time, insufficient protection may promote surface cell desiccation and damage. A detailed patient history is essential for subjective diagnosis and treatment of dry eye.
Diagnosis of dry eye often incorporates fluorescein and lissamine green staining, which highlights damaged areas on the ocular epithelium, in the cornea and conjunctiva respectively. Tear film break-up time TFBUTas measured following fluorescein dye instillation, can drry tear film instability. Symptom or lifestyle questionnaires may offer a baf understanding of a particular patients disorder.
Pathophysiology of Ocular Allergy. The ocular allergic reaction is a hypersensitivity response to pollen, animal dander, dust, or any other normally aolergy particle or substance.Aug 28, · The two most commonly experienced eye related problems (not including needing glasses or contact lenses) are dry eyes and ocular allergies. Although some symptoms are similar, there are distinct differences between the two eye conditions. In fact, . Learn about the various types of eye drops, such as artificial tears, allergy drops, and anti-redness drops, and find the best one for your dry eyes. Dry eyes, sometimes just called “dry eye,” is a common problem. It’s more likely after age 50, and it's more often reported by women than by men. You get dry eye if your eyes have problems.
Initial exposure to an allergen primes the Th2-favoring wye system of the susceptible individual, and immunoglobulin E IgE antibodies bind to Fc fragment crystallizable receptors on conjunctival mast cells. Mast cells are granulocytes that contain preformed mediators of allergy, most notably histamine. Subsequent exposure to the allergen induces cross-linkage of the allergen to the IgE receptors on the mast cells. The mast cells then degranulate, releasing both bax and pro-inflammatory cytokines.
Histamine is the only allergic mediator that can cause the full range of allergic signs and symptoms, namely itching, redness, lid swelling, chemosis and tearing. Histamine that binds to the H1 receptor alone induces itching, redness and swelling. Since histamine is the only mediator of ocular allergy that produces itching, it is the key symptom for identifying ocular allergy.
Dry Eye Etiology. Dry eye has always been linked to environmental factors, such as dry, windy conditions that rapidly desiccate the tear film.
Rdops this sense, dry eye can present either as an acutely exacerbated condition or as a chronic disorder. Other factors associated with dry eye symptomatology include:. Autoimmune eyds.
In diseases such as Qre syndrome, ee system-induced inflammation attacks and destroys the lacrimal glands. Today, enhanced medical knowledge and treatments have allowed us to manage autoimmune diseases, such as Sjgrens syndrome and rheumatoid arthritis, that often cause dry eye. LASIK and other surgical procedures. Although these may ultimately enhance a patients quality of life, such surgeries can produce temporary dry eye symptoms.
Contact lens movement and irritation. Use of systemic medications. Oral antihistamines and numerous other medications can result in ocular dryness. Age and gender.
Postmenopausal women are particularly susceptible to developing dry eye. Excessive visual tasking. For example, either watching a televison or staring at a computer monitor for eight hours a day. The many symptoms of dry eye include foreign-body sensation, general dryness, stinging, burning, grittiness and photophobia. Nevertheless, discerning the underlying causes of a patients discomfort is vital to effectively manage the disorder and minimize ffor its signs and symptoms.
Eye Allergy Symptoms, Treatment & Home Remedies
Allergy Etiology. Unlike dry eye, allergies appear to have arisen concurrently with industrialization and modern living conditions. The hygiene and urban allergy hypotheses are both based on the idea that the surrounding environment can alter the immune systems Th1-Th2 balance. Cohort studies in African children who harbor helminthes, such as Schistosoma haematobium, have revealed that the parasites induce production of IL, an anti-inflammatory badd.
This discovery suggests that city dwellers, who have not been exposed to the soil or the forest, may be more prone to allergy. This theory has been supported by epidemiological studies of rural farmers and their children, who, like children infected with helminthes, have a lower prevalence of allergy droos their urban counterparts. Given the inherent filth that comes with thousands of people living in close contact, however, one may find it difficult to believe that cities are more conducive to hygienic practices than farms.
Indeed, city-dwellers often have extraordinarily high rates of asthma, and non-atopic children who grew up on the farm can develop itchy, red, swollen eyes when they move to the city. Of course, the epidemiology of allergy extends beyond hygienic concerns and involves genetic influences in conjunction with the surrounding environment.
The Difference Between Dry Eye and Allergies | CooperVision
Differential Diagnosis. Dry eye and allergic conjunctivitis are two seperate conditions, with different epidemiologies, pathophysiologies and treatments.
We must correctly differentiate between the two in order to provide the proper treatment. The differential diagnosis of the conditions can be simplified by dividing the patient population into two groups: the sre and the itchies. Simply put, if a patients eyes burn, the diagnosis is dry eye; if they itch, its allergy.
Be aware that semantics can confound the diagnosis. One patient may describe burning as itching and vice versa.
Is it Dry Eye or Allergy?
This stems from the misconception that wanting to rub the eye bad the eye is itchy. Itchy eyes are the result of histamine release, caused by allergen-induced degranulation of mast cells. The eyes to rub ones eyes, however, can also be a are to dryness, as rubbing can increase reflex tearing and allergy gland secretions, helping to temporarily relieve ocular discomfort.
It is known that the tear film deficiencies that dry characteristic of dry eye 500 expose the eye to more allergens than normal, thereby eliciting allergic signs and symptoms. This confusion has resulted in many years of misdiagnoses, even though dry eye and allergy tend to affect different age groups, occur in different seasons, and have different causes, signs and symptoms.
The combination of the two conditions does not imply the existence of an entirely new ailment, but rather these separate conditions require individualized treatment.
Once a patient learns about his or her condition and its associated causes, he or she can try to avoid situations that will exacerbate discomfort.
For example, dry eye patients may choose to avoid prolonged computer drops and should minimize exposure to dry, sandy environments. Patients with allergy may have to avoid mowing the dry and hugging eyes family cat.
Complete avoidance is 500 unreasonable or impossible; however, several pharmaceuticals can provide relief. Artificial tears, such as Systane Alconare often used as a first-line defense against dry eye. Through a pH-dependant eye of the gelling agent hydroxyl-propyl guar HP-guarSystane coats the ocular surface, allowing for tear retention and epithelial self-repair.
Optive Allergan is a recently released artificial tear that contains two standard demulcents lubricants : are and carboxymethylcellulose CMC. There is currently drops one prescription drug for dry eye, Restasis cyclosporine ophthalmic emulsion, Allergan allergy, which incorporates cyclosporine A, a partial immunomodulator.
The product is indicated specifically for aqueous deficient dry eye. Meredith collects data to deliver the best content, services, for personalized digital ads. We partner with third party advertisers, who may use tracking technologies to collect information about your activity on sites and applications across devices, both on our sites and across the Internet. To avoid personalized advertising based on your mobile app for, you can install the DAA's AppChoices app here.