How is dry eye measured?
With a combination of a symptoms questionnaire, the time it takes your tears to break up after a blink, staining of the surface with dye, and an examination of the eyelid glands. There is no single number that defines dry eye, which is why the assessment is a set of findings rather than one result.
- Subject
- Surgery journey
- Topic
- Eye tests & scans
- Kind of question
- Other questions
- Last reviewed
- 22 September 2026
In more detail
The gland examination matters because a large share of dryness comes from the oil layer of the tear film rather than from its water content, and the treatment is different. A clinic that measures only tear quantity is measuring part of the problem.
What this answer depends on
- Whether the eyelids were examined as well as the tears
- Whether a questionnaire was used
- Whether the assessment was repeated on another day
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Where this answer sits
It is one of 483 answers in the vision and eye health knowledge base, filed under The surgery journey in Eye tests & scans . The subject page carries the answers either side of it, and the hub is searchable.
Subjects this question touches
The pages that answer the subject behind the question, rather than the question itself.
- Condition Dry eye
- Place Eye tests in Dubai
This information is for educational purposes and does not replace an examination by a qualified eye-care professional.
General answers cannot tell you what is happening in your own eyes. Only an examination by a qualified ophthalmologist can do that.
Sources & further reading
We prefer primary sources. Where a claim comes from a manufacturer, a single study or a regulator, it is labelled as such below.
- Dry Eye after Small Incision Lenticule Extraction (SMILE) versus Femtosecond Laser-Assisted In Situ Keratomileusis: A Meta-Analysis
A meta-analysis pooling several studies on dry eye after SMILE compared with femtosecond LASIK. It also documents where the included studies disagreed.
Used for The dry-eye discussion on the comparison and risks pages; Explaining that the evidence base is mixed rather than unanimous.
Link checked 22 September 2026
- Cataracts in adults: management (NG77)
Clinical guidance on when cataract surgery is indicated, what should be discussed before it, and what follow-up is expected.
Used for When cataract surgery is considered appropriate rather than cosmetic timing; What patients should be told before cataract surgery.
Link checked 23 September 2026