dry eye a common but still often-overlooked condition
Causes of Dry Eye in Risk Groups
Dry eye is caused by the change of the components in the tear film which is mainly induced by the change of the tear proteomic profile. The changes in tear protein happen before the symptoms appear. The earlier you detect the changes in tear protein, the sooner you can start a treatment.
In patients who use computers <3 hours/day, the lack of correlation between lactoferrin concentration in tears, Schirmer’s test results and clinical signs suggest that the tear protein electrophoresis could be an important tool in early diagnosis of DED and prevention of complications. Decreased levels of lactoferrin and lysozyme in those who use computers for >3 hours/day have been correlated with ocular discomfort, supporting the theory regarding the coexistence of ADDE and EDE in DE.
In a healthy eye, tears allow the contact lens to comfortably swim in the tear film above the cornea. A shortage of lacrimal fluid can lead to gaps in the tear film, causing the contact lens to irritate the surface of the eye. That, in turn, causes pain, redness, and itchiness. This effect can be further exacerbated if the lenses are low in quality or are poorly fitted to the eye. Such contacts absorb too much liquid from the tear film, causing the eye to lose vital moisture. This can also occur when traditional soft lenses are worn for an extended period of time
Surgical procedures, such as cataract surgery, along with their associated use of topical anaesthesia and use of antibiotics may result in reflex hyposecretion with a subsequent inflammation and/or aggravation of a pre-existing DED. The decrease of lactoferrin and lysozyme, as well as the increase of albumin reflect the presence of an inflammatory reaction with a severity that is statistically correlated with changes to other tear biomarker levels. The amplitude of these changes improves over time in a favorable post-surgery evolution. Moreover, topical antiglaucoma therapy (in particular benzalkonium chloride, used as preservative in topical medication and ocular hypotensive active molecule) can induce or exacerbate a pre-existing DED. Thus, in glaucoma patients receiving chronic therapy, tear protein electrophoresis could be an important tool not only for monitoring the pre-existing DED, but also for early diagnosis of a therapy-induced DED in patients without an apparent DED-related problem.
Diagnosis Steps
A comprehensive eye exam
An eye exam that includes a complete history of your overall health and your eye health can help your doctor diagnose the cause of your dry eyes.
A test to measure the volume of your tears.
Your doctor may measure your tear production using the Schirmer test. In this test, blotting strips of paper are placed under your lower eyelids. After five minutes your doctor measures the amount of strip soaked by your tears. Another option for measuring tear volume is the phenol red thread test. In this test, a thread filled with pH-sensitive dye (tears change the dye color) is placed over the lower eyelid, wetted with tears for 15 seconds and then measured for tear volume.
A test to determine the quality of your tears
Other tests use special dyes in eyedrops to determine the surface condition of your eyes. Your doctor looks for staining patterns on the corneas and measures how long it takes before your tears evaporate.
A tear osmolarity test
This type of test measures the composition of particles and water in your tears. With dry eye disease, there will be less water in your eyes
Tear samples to look for tear protein markers
Tear protein changes including elevated matrix metalloproteinase-9 or decreased lactoferrin
Screening for Dry Eye With Newly Developed TearPro
