Corneacare Logo
  • CorneaCare Logo
  • Shop
    • Shop All
    • Eyelid Hygiene
    • Eye Vitamins
    • Eye Drops
    • Eyecare Bundles
  • Education
    • Dry Eye Disease
      • Dry Eye 101
      • Causes & Diagnosis
      • Lifestyle
      • Treatment
      • Why It Matters
    • Eye Health & Wellness
    • Eye Glossary
    • Take the Quiz
  • Community
  • App
  • Take the Quiz
  • Contact us
  • Login
  • My Account
Login
Cart Icon 0
Take the Quiz
  • Shop
  • Education
  • Our App
  • Take the Quiz
  • Shop
  • Education
  • Our App
  • Take the Quiz

A-Z Glossary

Table of Contents

Intraocular Pressure

Courtney Dryer, OD
Written byCourtney Dryer, OD
Courtney Dryer, OD
Courtney Dryer, ODOptometristCharlotte, NC

Bio

Dr. Courtney Dryer earned her doctorate from Southern College of Optometry, Memphis, Tennessee in 2011. She opened her own practice Autarchic Spec Shop in 2013 in Charlotte, NC. She has had the privilege of writing for numerous optometric publications and serving in various industry capacities. In 2015, Vision Monday named her a rising star and one of the most influential women in optometry. Her optometric passions include practice management, specialty contact lenses, and dry eye management.

  • Last updated November 4, 2022

What is Intraocular Pressure?

Intraocular pressure (IOP) is a measure of the pressure within the eye. Aqueous fluid is produced within the eye and should flow out through the trabecular meshwork. If there is a dysfunction, the IOP will increase resulting in damage to the optic nerve.  Lowering intraocular pressure is currently the main therapeutic measure to treat and manage glaucoma. All types of glaucoma demonstrate optic-nerve damage (cupping, pallor, or both) associated with peripheral visual field defects.

Key Takeaways

  • Intraocular pressure (IOP) is a measurement of aqueous production versus elimination from the eye.
  • Measuring IOP is the main way to manage and treat Glaucoma
  • Many internal and external factors affect IOP over time.
You brush your teeth,
moisturize your skin,
what about your eyes?
Take the quiz
Eyecare Quiz on Cellphone

Understanding Intraocular Pressure

Intraocular pressure (IOP), the pressure within the eyeball, is a function of the ciliary body’s aqueous production and elimination of aqueous humor through Schlemm’s canal. Normal IOP helps maintain the eyeball shape and allows the proper refraction of light in the anterior part of the eye. IOP is not a fixed measurement but changes over time with intrinsic circadian rhythm and can change in various lifestyle-related situations. Dietary habits and exercise can affect IOP.

Risk Factors for Intraocular Pressure

Studies report that percent body fat, systemic blood pressure, pulse rate, albumin, and HbA1c are correlated with high IOP while older age is correlated with low IOP.

Determining the target IOP in glaucoma patients is multi-faceted and requires attention to family history, glaucoma type, severity of disease, age, race, family history, corneal thickness, hysteresis, and initial IOP. Some patients will still have disease progression despite achieving target IOP. 

Intraocular Pressure Symptoms

Patients are unlikely to experience any symptoms of high intraocular pressure if it’s elevated chronically. However, an acute rise in intraocular pressure, such as in angle closure glaucoma, will present with pain, redness, photophobia, decreased vision and headache.

What is Normal Intraocular Pressure?

Normal intraocular pressure ranges from 11-21 mmHg. Ocular hypertension usually applies to eyes with an IOP greater than the statistical upper limit of normal (21 mmHg). A thicker cornea leads to an overestimate of the IOP, while a thinner cornea may lead to underestimation of IOP. Large diurnal IOP fluctuation is an independent risk factor for glaucoma progression besides elevated IOP. 

Diagnosing Intraocular Pressure

Intraocular pressure can be checked by your eye doctor. Tonometry can be performed using a variety of instruments including Goldman’s, iCARE, and tonopen.

Intraocular Pressure Treatment

Intraocular pressure is routinely checked by your eye doctor.  If glaucoma or ocular hypertension is suspected, you may be asked to have your pressure checked every 3-6 months. If your glaucoma medications have been changed, your doctor will want to assess the effect the medication is having on your IOP and will check your pressure more often.  In addition, if your doctor places you on a steroid eye drop for an ocular condition, they will have you return to have your IOP checked.

Bibliography

  1. Bhartiya S, Gangwani M, Kalra RB, Aggarwal A, Gagrani M, Sirish KN. 24-hour Intraocular pressure monitoring: the way ahead. Rom J Ophthalmol. 2019 Oct-Dec;63(4):315-320. PMID: 31915728; PMCID: PMC6943292.
  2. Feroze KB, Khazaeni L. Steroid Induced Glaucoma. [Updated 2022 Mar 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-.
  3. Kim YW, Park KH. Exogenous influences on intraocular pressure. Br J Ophthalmol. 2019 Sep;103(9):1209-1216. doi: 10.1136/bjophthalmol-2018-313381. Epub 2019 Mar 25. PMID: 30910873.
  4. Sit AJ, Pruet CM. Personalizing Intraocular Pressure: Target Intraocular Pressure in the Setting of 24-Hour Intraocular Pressure Monitoring. Asia Pac J Ophthalmol (Phila). 2016 Jan-Feb;5(1):17-22. doi: 10.1097/APO.0000000000000178. PMID: 26886115.

Related Terms

Loading...

Bowman’s Layer

is the second layer of the cornea, which is the clear outer covering of the eye

Schlemm’s Canal

is a cylindrical vessel that collects fluid (aqueous) inside the eye and drains it into blood vessels

Phacoemulsification

also called “small incision cataract surgery” is the most common type of cataract surgery

Uvea

is a highly vascular layer that lines the sclera, and its primary function is to provide nutrition to the eye

Meibomianitis

is chronic inflammation of the meibomian glands that can affect both your upper and lower eyelids

Epiretinal Membrane

is fibrous tissue (scar tissue) that forms on the top of the retina

Related Articles

Loading...
  • Eye Health & Wellness

Eye Bag Surgery Gone Wrong

7 min read

Understand the complications of eye bag surgery gone wrong and how it can damage the function and health of your eyes.
Heather Cottrell

Heather Cottrell

  • Eye Health & Wellness

Sharp Stabbing Pain in Eye that Comes and Goes

7 min read

Find out what’s causing that sharp stabbing pain in your eye that comes and goes. And when to see a doctor!
Heather Cottrell

Heather Cottrell

  • Eye Health & Wellness

A Black Spot in Vision of One Eye

7 min read

A black spot in the vision of one eye is probably a harmless floater, but there can be a more serious cause requiring treatment.
Heather Cottrell

Heather Cottrell

Logo_Corneacare_White

    • Shop
    • Wholesale
    • Education
    • Community
    • App
    • Eye Glossary
    Menu
    • Shop
    • Wholesale
    • Education
    • Community
    • App
    • Eye Glossary
    • Contact
    • Terms of service
    • Privacy policy
    • Shipping & Returns
    • Contact
    • Terms of service
    • Privacy policy
    • Shipping & Returns
    • Education
    • Shop
    • Wholesale
    • Contact
    • Terms of service
    • Privacy policy
    • Shipping & Returns
    • Education
    • Shop
    • Wholesale
    • Contact
    • Terms of service
    • Privacy policy
    • Shipping & Returns
    • Education
    • Shop
    • Wholesale
    • Contact
    • Terms of service
    • Privacy policy
    • Shipping & Returns
    • Education
    • Shop
    • Wholesale
    • Contact
    • Terms of service
    • Privacy policy
    • Shipping & Returns
    Instagram Facebook_Pink Youtube Twitter Tiktok
    Copyright – © 2023 CorneaCare, Inc. ⚡️ All rights reserved
    *These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease

    Wholesale inquiry

    Please fill out the form below, and we will be in touch shortly.

    20% OFF personalized, convenient and effective eyecare
    20% OFF personalized eyecare
    Take the quiz
    Take the quiz