Fluorescein Dye Use in Corneal Tear Inspection

Primary Applications of Fluorescein Dye

The American Academy of Ophthalmology recommends fluorescein dye for corneal epithelial defect visualization, as it stains areas of the corneal epithelium where intercellular junctions are disrupted, allowing the dye to permeate into the tissue and highlight injuries 1, 3
Fluorescein dye is used in tear film stability assessment, specifically in tear break-up time (TBUT) testing, to evaluate the stability of the precorneal tear film 1, 2

The proper technique for fluorescein application involves using a saline-moistened strip to the inferior tarsal conjunctiva, and avoiding fluorescein-anesthetic combination drops as anesthetics may affect test results 1, 2, 4
After instillation, the ocular surface should be examined through a biomicroscope using a cobalt blue filter, and optimal visualization of corneal staining can be achieved by waiting approximately 2 minutes after application and using a yellow filter in conjunction with the cobalt blue light 1, 2, 3

Normal eyes may show mild fluorescein staining, particularly in the morning, while dry eye typically presents with exposure-zone punctate or blotchy fluorescein staining 1, 3, 4
Viral keratoconjunctivitis often shows diffuse corneal and conjunctival staining, and staphylococcal blepharitis/MGD typically shows staining of the inferior cornea and bulbar conjunctiva 1, 3, 4

Fluorescein is more easily visualized on the cornea than on the conjunctiva and causes less ocular irritation compared to rose bengal dye 1, 2, 3

Fluorescein staining should be performed before instillation of any other eyedrops, and manipulating eyelids before evaluation should be avoided to prevent false results 1, 2, 4
Recurrent tear break-up in the same area may indicate localized anterior basement-membrane abnormalities 1, 2