Clinical exam first step in dry eye diagnosis
LONDON — Innovative methods for diagnosing dry eye are emerging, but there is no ideal test, a speaker said here.
The first step to diagnosis is a thorough clinical exam.
“Do not go straight to the slit lamp, but look at the patient in general. Have a look at their hands, their joints, their parotid glands and thyroid, and then move on to slit lamp examination,” Christopher Liu, FRCOphth, said at the EuCornea Congress. Liu spoke in place of intended presenter, Vishal Jhanji, FRCOphth.
Tear film quality can be examined at the slit lamp, before or after staining, Liu said. The traditional methods of measuring tear breakup time and Schirmer’s tear test are fast and inexpensive, but have disadvantages.
Tear breakup time yields subjective results that do not account for tear osmolarity or the presence of inflammation, which are hallmarks of dry eye, Liu said. Schirmer’s tear test also does not account for tear osmolarity or the presence of inflammation and can be uncomfortable, with some clinicians choosing to anesthetize their patient’s eye first.
New, innovative diagnostics for dry eye can be done in the clinic, or samples may be obtained for laboratory examination, according to the presentation.
Recent innovations in measuring tear osmolarity include use of electrical impedance and measuring the freezing temperature of tear samples.
In vivo confocal microscopy is a minimally invasive, high-resolution assessment of the ocular surface that shows changes in epithelium, immune and inflammatory cells, corneal nerves, keratocytes and meibomian glands.
Tear film stability analysis is a quantitative analysis of dynamic changes in tear stability, whereas interferometry is a lipid layer analysis.
Samples of tear film may contain low protein content and proinflammatory markers; presence of matrix metalloproteinase 9 is a nonspecific inflammatory marker that is often sought because levels are often higher in dry eye, Liu said.
Finally, measuring the temperature of the ocular surface may be an indicator of the rate at which tears evaporate.
Disclosure: Jhanji has no relevant financial disclosures.