Tonometry is the measurement of intraocular pressure (IOP), one of the main risk factors for glaucoma. Different instruments and techniques can be used to obtain this value.
Techniques
Goldmann applanation tonometry estimates pressure by flattening a small area of cornea, while non-contact methods use an air puff. Handheld devices are useful when the standard slit-lamp approach is not feasible.
- Corneal thickness and biomechanics influence measured IOP
- Single readings are less informative than a series over time
- High or fluctuating IOP increases the chance of optic nerve damage
- Tonometry is interpreted alongside nerve appearance and visual fields
