[Ocular surface investigations in dry eye].

Area of Science:

• Ophthalmology
• Tear Film Science
• Ocular Surface Disease

Background:

• Dry eye is a multifaceted condition affecting the tear film, lacrimal glands, eyelids, and ocular surface cells.
• Numerous diagnostic investigations exist, targeting tear film structure, function, and ocular surface integrity.

Purpose of the Study:

• To review and assess the diagnostic techniques for dry eye disease.
• To highlight the utility and limitations of various investigative methods.

Main Methods:

• Review of established and emerging diagnostic techniques for dry eye.
• Inclusion of methods assessing tear film (e.g., osmolarity, protein analysis), ocular surface morphology (e.g., videokeratography, confocal microscopy), and cellular alterations (e.g., impression cytology).

Main Results:

• A wide array of tests exist, including tear meniscus measurement, fluorophotometry, meibometry, tear osmolarity, and corneal imaging.
• Impression cytology, confocal microscopy, and molecular biology techniques aid in cellular assessment.
• Tear osmolarity, electrophoresis, and quantification of proteins like lysozyme and lactoferrin are considered most useful.
• Technical challenges in tear collection and lack of standardization are significant limitations.

Conclusions:

• Dry eye diagnosis relies on a spectrum of tests, with tear osmolarity and specific tear protein analysis being highly valuable.
• Despite limitations, these methods provide crucial insights into the pathophysiology of dry eye disease.
• Extraocular tests may aid in diagnosing associated conditions like Sjögren's syndrome.