Tonometry measures intraocular pressure using a contact or non-contact method. The result informs eye assessment but does not by itself confirm or exclude glaucoma.
Patients having a routine eye examination; those with suspected glaucoma or ocular hypertension; people with established glaucoma who need IOP monitoring; and selected patients after ophthalmic procedures as advised by a clinician.
Tonometry may form part of assessment for eye pain, halos, blurred vision, marked redness or other complaints. These symptoms are not specific to high IOP, and acute symptoms require medical assessment.
Glaucoma, glaucoma suspect status, ocular hypertension, family history of glaucoma, corticosteroid exposure and selected postoperative states. The clinician determines the monitoring interval.
Corneal thickness and biomechanics, refractive or corneal surgery, the specific tonometer, measurement technique and diurnal IOP variation can affect the result. Contact testing may be temporarily unsuitable with epithelial defects or active corneal inflammation. Corneal thickness matters, but should not be used for a simplistic formula-based correction of IOP.
A single high or normal reading does not establish the diagnosis.
Do not apply one universal “normal range” without considering the method and clinical context. For monitoring, compare results obtained with comparable methods and conditions where possible.
After LASIK, PRK or other corneal procedures, some methods may underestimate or otherwise alter the reading.
Routine tonometry does not require pupil dilation, although dilation may be needed for other tests during a comprehensive examination.
No special preparation is usually needed. Remove contact lenses, report medications and previous surgery, relax during the measurement and avoid squeezing the eyelids.
Bring previous intraocular-pressure results, particularly if followed for glaucoma or ocular hypertension. Contact lenses are usually removed before testing; bring a case and glasses.
Tell the specialist about glaucoma drops, systemic steroids, corneal operations and laser vision correction.
Do not rub the eyes immediately before testing.
Report any eye injury, severe pain or marked inflammation before the procedure.
Sudden severe eye pain, abrupt vision loss, marked redness, nausea or vomiting with eye symptoms, eye trauma or other acute changes.
A routine tonometry appointment does not replace urgent medical assessment.
The tonometer does not diagnose glaucoma automatically.
Book a consultation
The specialist reviews the goal, lenses, drops, operations, injuries and factors affecting method selection.
Takes: 1 min
Non-contact testing needs no special anaesthesia.
Takes: 1 min
The patient fixates and avoids squeezing the lids.
Takes: 1 min
The specialist checks reproducibility and repeats the measurement if needed.
Takes: 1 min
The ophthalmologist compares pressure with other findings to decide on repeat checks, pachymetry, gonioscopy, OCT, perimetry or other tests.
Takes: 2 min
Tonometry provides an intraocular-pressure reading for diagnosis and follow-up.
Pressure measurements complement optic nerve and visual field assessment when glaucoma is suspected.
Changes in measurements help determine whether treatment is sufficient or needs review.
The doctor selects a suitable tonometry method and considers corneal characteristics when interpreting results.
Book an intraocular pressure measurement if your clinician has recommended IOP monitoring or you are undergoing an eye examination. If the result is unusual, the ophthalmologist can determine what testing is needed next.
A team of experienced doctors across specialties.
Candidate of Medical Sciences; Highest-category ophthalmologist
Highest-category ophthalmologist
Highest-category ophthalmologist
Highest-category ophthalmologist
Highest-category ophthalmologist
Highest-category ophthalmologist
Highest-category ophthalmologist
Highest-category ophthalmologist
Second-category ophthalmologist
Second-category ophthalmologist
Intraocular pressure reflects the balance between aqueous humour production and outflow.
Tonometry provides a quantitative IOP measurement, but a single number is not a diagnosis. High IOP does not always mean glaucoma, and glaucoma can develop with IOP values within the statistical normal range.
The reading is therefore interpreted together with optic nerve findings, OCT, visual fields, gonioscopy, pachymetry and other tests as indicated. For follow-up, the measurement method, corneal properties and timing of the test matter.
Eye and instrument preparation
Non-contact testing requires no special anaesthesia. Contact-method preparation follows the protocol and may include a local anaesthetic.
Intraocular-pressure measurement
The patient fixates without squeezing the lids. The device takes one or more measurements per eye.
Measurement quality check
The specialist checks reproducibility and repeats if needed. An unusual result must be interpreted in its clinical context.
The clinician still considers risk factors and optic nerve findings. Normal IOP does not exclude glaucoma.
Repeat measurement, corneal thickness assessment, gonioscopy, OCT and visual fields may be needed. Treatment is not based on a single reading alone.
The difference may reflect device principles and corneal properties. The clinician selects the method to use as the main reference for future follow-up.
Altered corneal biomechanics and preoperative measurements, if available, should be considered.
IOP is compared with the individual target set by the treating clinician, together with structural and functional change over time.
Why one IOP number is not enough to assess glaucoma
Glaucoma is an optic neuropathy, while IOP is a major risk factor and the main modifiable treatment target. A clinician therefore does not make the diagnosis from tonometry alone. Optic nerve evaluation, OCT of the retinal nerve fibre and ganglion cell layers, visual fields, gonioscopy and pachymetry may be required.
This approach helps distinguish ocular hypertension from glaucoma and avoids missing glaucoma when IOP appears “normal”.
Kazakhstan’s first specialized ophthalmology institute, operating since 1933.
Modern diagnostics and surgery using world-class equipment.
Leading ophthalmologists in Kazakhstan, scientists and experienced surgeons.
More than 30,000 operations and around 270,000 consultations annually.
Kazakhstan’s first specialized ophthalmology institute, operating since 1933.
Modern diagnostics and surgery using world-class equipment.
Leading ophthalmologists in Kazakhstan, scientists and experienced surgeons.
More than 30,000 operations and around 270,000 consultations annually.
Kazakhstan’s first specialized ophthalmology institute, operating since 1933.
Modern diagnostics and surgery using world-class equipment.
Leading ophthalmologists in Kazakhstan, scientists and experienced surgeons.
More than 30,000 operations and around 270,000 consultations annually.
