From the Guidelines
The Double Dye test is not a recommended diagnostic procedure for evaluating tear drainage system function, as there is no evidence to support its use in current clinical practice. The test, which involves applying two different colored dyes to the eyes at different times, is not mentioned in the provided evidence as a diagnostic tool for tear drainage system function. Instead, the evidence focuses on the use of fluorescein, rose bengal, and lissamine green dyes to assess ocular surface staining and tear film quality 1.
Diagnostic Tests for Dry Eye
The provided evidence outlines various diagnostic tests for dry eye, including:
- Aqueous tear production (Schirmer test)
- Fluorescein dye disappearance test/tear function index
- Fluorescein tear break-up time
- Ocular surface dye staining (example: fluorescein, lissamine, rose bengal)
- Lacrimal gland function
- Tear osmolarity
- Matrix metalloproteinase-9
These tests are used to evaluate tear production, tear quality, and ocular surface health, but do not include the Double Dye test as a recommended diagnostic procedure 1.
Ocular Surface Dye Staining
Ocular surface dye staining is a diagnostic tool used to assess the health of the ocular surface. Fluorescein, rose bengal, and lissamine green dyes can be used to stain the ocular surface, with each dye having a different staining profile 1.
- Fluorescein dye stains areas of the corneal and conjunctival epithelium where there is sufficient disruption of intercellular junctions to allow the dye to permeate into the tissue.
- Rose bengal staining is more intense on the conjunctiva than on the cornea and stains ocular surface cells that lack a mucous coating as well as debris in the tear film.
- Lissamine green dye has a staining profile similar to that of rose bengal dye but causes less ocular irritation.
Clinical Implications
In clinical practice, the choice of diagnostic test depends on the patient's symptoms and clinical findings. The provided evidence suggests that a detailed review of systems and clinical findings should guide the selection of diagnostic tests for dry eye 1.
- Aqueous tear production (Schirmer test) can be used to diagnose aqueous tear deficiency.
- Fluorescein dye disappearance test/tear function index can be used to evaluate tear drainage.
- Ocular surface dye staining can be used to assess ocular surface health.
However, the Double Dye test is not a recommended diagnostic procedure for evaluating tear drainage system function, and its use is not supported by current evidence.
From the Research
Double Dye Test Overview
- The double dye test is a diagnostic tool used to evaluate dry eye syndrome, with studies comparing the effectiveness of different dyes such as rose bengal, lissamine green, and fluorescein 2, 3, 4.
- Research has shown that lissamine green and rose bengal have good clinical correlation, but lissamine green is better tolerated by patients 2.
- The use of a mixture of 1% fluorescein and 1% lissamine green has been found to be useful in diagnosing dry eye syndrome and assessing therapeutic effects 3.
Comparison of Dyes
- A study comparing rose bengal and lissamine green found that both dyes showed similar staining patterns, but rose bengal caused greater patient discomfort 2.
- Another study found that double vital staining with 1% fluorescein and 1% lissamine green correlated with symptoms and some ocular surface parameters in patients with dry eye 3.
- The use of sodium fluorescein staining of the cornea has also been compared with other eye solutions, with results showing that artificial tears with cyclosporine 0.05% emulsion and lipids containing omega-3 remain in the cornea for longer periods 5.
Grading and Interpretation of Staining
- The Oxford Scheme has been proposed for grading ocular surface staining in dry eye, using a series of panels to guide the grading of staining severity 4.
- Research has highlighted the importance of understanding the basic interactions between the ocular surface cells and fluorescein, as the clinical understanding and interpretation of corneal surface fluorescence is based on assumption and clinical intuition rather than solid evidence-based science 6.
- The use of vital dyes such as fluorescein, lissamine green, and rose bengal, in conjunction with appropriate absorption filters, is recommended for use in clinical trials 4.