Tests Required Before LASIK: The Complete Work-Up

Why so many tests for a five-minute procedure?

LASIK permanently reshapes the cornea. The safety of that decision rests entirely on measurements taken beforehand — this work-up is where good refractive surgery actually happens.

The tests, one by one

Refraction (spectacle power)

Your exact prescription is measured, often in two ways (with and without dilating drops), and compared with previous records to confirm stability.

Pachymetry (corneal thickness)

Ultrasound or optical pachymetry measures corneal thickness at the centre and thinnest point. This determines how much tissue can safely be treated.

Corneal topography

Maps front-surface curvature to detect irregular astigmatism and early keratoconus. Read the topography guide.

Corneal tomography

Where used, tomography images the front and back corneal surfaces and maps thickness across the whole cornea — the most sensitive screening for ectatic (weakening) change.

Dry-eye evaluation

Tear break-up time, surface staining and gland assessment identify dry eye, which is treated before surgery to improve measurement accuracy and healing. About dry eye.

Pupil assessment

Pupil size in dim light is measured and considered in planning the treatment zone and counselling about night-vision effects.

Dilated retinal examination

Where indicated — especially for moderate-to-high myopia — the retinal periphery is examined for thinning or holes, which are treated before any refractive surgery. High power and eye health.

Complete eye-health check

Eye pressure, lens clarity, eyelids and general ocular examination complete the picture, along with your medical and medication history.

Preparing for the work-up

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• Stop soft contact lenses for the period advised (often several days to two weeks; longer for rigid lenses) so the cornea returns to its natural shape.
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• Bring old spectacle prescriptions if available — they help establish stability.
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• Expect dilating drops; near vision may blur for a few hours, so plan travel accordingly.
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After the work-up, your results are reviewed with you and a procedure recommendation — LASIK, PRK, ICL or no surgery — is made from the data. Book a refractive evaluation.

Information on this page is for general education and does not replace an examination, diagnosis or personalised medical advice from a qualified eye-care professional.

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