Dry Eye Syndrome
Dry eye syndrome (DES) or keratoconjunctivitis sicca (KCS) is a common disorder of the tear film caused by decreased tear production or increased evaporation and manifests with a wide variety of signs and symptoms. The present review from interpretation of the literature gives detailed information on the prevalence, definition, causes, diagnostic tests, and medical management of dry eye disease. A number of systems contribute to the physiological integrity of the ocular surface and disruption of system may or may not produce symptoms.
Due to the wide prevalence and number of factors involved, newer, more sensitive diagnostic techniques and novel therapeutic agents have been developed to provide ocular delivery systems with high therapeutic efficacy. The aim of this review is to provide awareness among the patients, health care professionals, and researchers about diagnosis and treatment of KCS and recent developments and future challenges in management of dry eye disease.
Diagnosis of Dry Eyes Syndrome
Diagnostic tests are used for different purposes such as assessing eligibility in a clinical trial and monitoring changes quantitatively, diagnosing in every day clinical practice by ophthalmologists, and characterizing dry eye as part of clinical syndrome such as Sjögren’s syndrome. Recently tests such as tear film breakup time (TBUT), epithelial staining, and ocular surface disease index (OSDI) are used to find correlation between ocular surface disorders, for example, meibomian gland dysfunction, dry eyes, and lifetime computer use/comfort levels .The diagnosis of keratoconjunctivitis sicca (KCS) is made by combining information obtained from the physical examination and performing diagnostic tests. Poor correlation between clinical signs and patient symptoms would require the use of multiple tests. Generally two or more tests are performed to permit an absolute diagnosis of DES. Symptom questionnaires can also be used to help establish a diagnosis of DES and to assess the effects of treatments or to grade disease severity.
The main symptom of dry eyes is dry and gritty feeling in the eyes. The additional symptoms include burning or itching in the eyes, foreign body sensation, excess tearing, pain and redness of the eyes, and photophobia in some cases. Sometimes it is also associated with a stringy discharge and blurred, changing vision. Symptoms are found to worsen in dry weathers, with low humidity and higher temperatures.
The treatments of keratoconjunctivitis are varied. The goals of treatment are to relieve the symptoms of dry eye, improve the patient’s comfort, return the ocular surface and tear film to the normal state, and, whenever possible, prevent corneal damage. Treatment may range from education, environmental or dietary modifications, artificial tear substitutes, punctal plugs, and topical and/or systemic anti-inflammatory medications to surgery.
Dry eye syndrome is the most common ophthalmic manifestation and untreated dry eye can cause increased risk of ocular infection, corneal ulcer, and blindness. The clinical diagnosis of dry eye is challenging due to extensive variety of signs and symptoms and the ambiguity in the etiology and pathophysiology of the disease. Unclear symptoms could confuse the clinician with symptoms of other condition, such as conjunctivochalasis (which can easily induce an unstable tear film) or delayed tear clearance (which is a frequent cause of ocular irritation)
Conventional tests for diagnosis include Schirmer test, TBUT, and ocular staining; as mentioned above, some of them have low degree of standardization and some are invasive. The invasive nature of some diagnostic tests can make interpretation challenging. A tear film is a dynamic, open system subject to numerous internal and environmental variations leading to misinterpretations of the obtained result. Recent studies have shown that less than 60% of subjects with other objective evidence of DED are symptomatic. The current treatment is based on the use of topically applied artificial tears: tear retention management, stimulation of tear secretion, and use of anti-inflammatory drugs. New therapeutic strategies and novel drug delivery systems using future pharmaceutical compounds designed to reduce key inflammatory pathways and restore healthy tear film along with incorporation of improved endpoints for clinical trials will lead to successful management of dry eyes or keratoconjunctivitis sicca in the future.
The overarching complexity of the dry eye disease makes it challenging to diagnose and manage accurately. With development of objective tests with precise diagnostic value and minimal disruption of physiological function, accurate diagnosis of disease is possible. Recent knowledge about causes, symptoms, and diagnostic tests of KCS provides better opportunities for improving medical management. Development of new potential drugs and different colloidal delivery systems definitely provides a ray of hope for more effective treatment of this widely prevalent and debilitating disease.