Introduction
Tonometry is one of the most common procedures performed by an ophthalmologist to check the pressure of the eyes.
Definition
Tonometry is a diagnostic procedure performed to measure the intraocular pressure (IOP) of the eyes.
Purposes
- To identify the elevated IOP.
- To perform as a part of routine eye examination since elevated IOP may cause risk of developing glaucoma and optic neuritis.
Types
- Goldmann applanation tonometry test.
- Non-contact tonometry.
- Electronic tonometry.
- Schiotz tonometry.
Indications
- Patients aged between 18 and 50 years (eye checkup must be done at least once every 2 years).
- Family history of glaucoma.
- Near sightedness or far sightedness.
- Chronic eye conditions.
- Past history of eye injury.
- Diabetes mellitus and hypertension.
- Usage of corticosteroid medications for prolonged periods of time.
- Blurred vision and gradual loss of peripheral vision.
- Severe eye pain.
- Halos around lights.
- Reddening of eyes.
Contraindications
- Suspected or known ocular infection.
- Frequent blinking that cannot be controlled voluntarily.
- Sensitivity to topical anesthetic.
- Ruptured globe.
- Infection.
- Unhealed corneal abrasion.
Articles
1) Preparation of the Equipment
| Articles | Purpose |
| Applanation/Goldmann tonometry/non-contact tonometer | To measure intraocular pressure. |
| Ocular response analyzer | To evaluate the elasticity of the cornea. |
| Pneumotonometer | To determine irregular cornea surface. |
2) Preparation of the Patient
- Ask the patient to remove contact lens before the test.
- Determine whether there is any history of corneal ulcers or eye infections.
- Enquire about prescription or intake of any medication before the test.
- Ask about the family history of glaucoma.
Procedure
| Nursing Action | Rationale | |
| 1. | Explain the procedure to the patient. | Allays anxiety and gains cooperation from the patient. |
| 2. | Obtain informed consent from the patient. | Serves as legal evidence. Prevents litigation of the staff. |
| 3. | Goldmann tonometry test | |
| Instill the eye drops as per the physician’s order. | General preparation before the procedure. | |
| Position the patient sitting on a chair. | Provides comfort to the patient. | |
| Ask the patient to rest the chin and forehead on the support provided. | Provides clear visibility of the eye during examination. | |
| The lamp is moved toward the eye until the tip of the tonometer touches the cornea. | Helps to measure the pressure. | |
| 4. | Tonopen test | |
| Instill eye drops as per the physician’s order. | ||
| Position the patient sitting on a chair. | To enhance comfort. | |
| The device is used to touch the surface of the cornea. | To record eye pressure. | |
| 5. | Non-contact method | |
| Ask the patient to stare straight into the examining device. | To understand the changes and report promptly for seeking medical support. | |
| A tiny beam of light reflects into the cornea. | To detect pressure on the eye. | |
| Instruct the patient to look at the light; a puff of air blows into the patient’s eye. | The air bounces back to the tonometer and gives the reading of intraocular pressure. | |
| 6. | Document the procedure; Record the date, time, and patient’s response to the procedure.Monitor the intake and output. | Serves as legal evidence and prevents duplication of care. |
Special Considerations
- Remove lenses before testing to avoid inaccurate readings or contamination.
- Scarring, edema, or keratoconus can distort readings note these in documentation and consider alternative methods.
- Use non-contact or rebound tonometry for minimal discomfort. Distraction techniques or parental presence may help.
- Be mindful of dry eyes, tremors, or cognitive impairment. Provide extra time and clear instructions.
- Avoid pressure on healing corneas or recent grafts; consult ophthalmology before proceeding.
- Ensure the tonometer is calibrated regularly to maintain accuracy.
- Method Selection:
- Applanation (e.g., Goldmann): Most accurate but requires corneal contact and anesthetic drops.
- Non-contact (Air Puff): Useful for screening but less precise.
- Rebound Tonometry: Ideal for children or home monitoring.
- Take multiple readings and average them if results vary.
- Clean the tonometer tip between patients using manufacturer-approved methods.
- Essential before and after the procedure.
- Use when available, especially in high-risk or immunocompromised patients.
REFERENCES
- Annamma Jacob, Rekha, Jhadav Sonali Tarachand: Clinical Nursing Procedures: The Art of Nursing Practice, 5th Edition, March 2023, Jaypee Publishers, ISBN-13: 978-9356961845 ISBN-10: 9356961840
- Omayalachi CON, Manual of Nursing Procedures and Practice, Vol 1, 3 Edition 2023, Published by Wolters Kluwer’s, ISBN: 978-9393553294
- Sandra Nettina, Lippincott Manual of Nursing Practice, 11th Edition, January 2019, Published by Wolters Kluwers, ISBN-13:978-9388313285
- Adrianne Dill Linton, Medical-Surgical Nursing, 8th Edition, 2023, Elsevier Publications, ISBN: 978-0323826716
- Donna Ignatavicius, Medical-Surgical Nursing: Concepts for Clinical Judgment and Collaborative Care, 11th Edition ,2024, Elsevier Publications, ISBN: 978-0323878265
- Lewis’s Medical-Surgical Nursing, 12th Edition,2024, Elsevier Publications, ISBN: 978-0323789615
- AACN Essentials of Critical Care Nursing, 5th Ed. Sarah. Delgado, 2023, Published by American Association of Critical-Care Nurses ISBN: 978-1264269884
Stories are the threads that bind us; through them, we understand each other, grow, and heal.
JOHN NOORD
Connect with “Nurses Lab Editorial Team”
I hope you found this information helpful. Do you have any questions or comments? Kindly write in comments section. Subscribe the Blog with your email so you can stay updated on upcoming events and the latest articles.
