Adapted from the Guidelines of the Royal College of Ophthalmologists (UK) 1997

ABSOLUTE CONTRAINDICATIONS

Monocularity or severe amblyopia
Severe dry eye disease
Severe local infective or allergic conditions:
Blepharitis (should be treated before surgery)
Previous Herpes Simplex or Zoster keratitis
Allergic eye disease severe enough to require regular treatment
Cataract 

Corneal abnormalities:
    Absent or decreased sensation
    Unstable Keratoconus
    Irregular astigmatism (with present lasers)
    Corneal vascularisation

Systemic Conditions:
    Collagen diseases - Rheumatoid Arthritis, SLE
    Cytotoxic or steroid drugs
    Pregnancy

RELATIVE CONTRAINDICATIONS

Glaucoma (cf. Ophthalmology 104, 355-359, March 1997)
Diabetes Mellitus
Unstable refraction
Low myopes approaching presbyopia - need counselling. See monovision.
Inappropriate motivation or unreasonable expectation

PSYCHOLOGICAL PROBLEMS

Perfectionist or obsessive personality:
Unrealistic expectations:
    (Bigger the prescription the bigger the spread of results.
    Large cylinders less predictable than large sphere)