Keep the IOP target in range

Clinically, prospective studies on glaucoma have enabled us to focus our efforts and, thus, help prevent the development of glaucoma and/or slow glaucomatous progression through IOP reduction.^1,2 However, with an estimated prevalence of nearly 80 million people worldwide having glaucoma this year, how do we personalize this treatment goal for each patient?³

ESTABLISH A RANGE

Each eye that needs treatment must have a personalized target IOP range prior to starting treatment, or an upper mean IOP limit that helps slow glaucomatous progression, while minimizing the effect on quality of life.

The reason: This first target IOP range acts as an initial guide to immediate treatment options, while representing a doctor-patient decision endpoint that takes into consideration potential adverse risks of medication and patient preferences. In short, the initial target IOP range is a balance between the likelihood of vision loss and the patient’s quality of life.

To arrive at a personalized target IOP range, we must take into account the patient’s:⁴

• Estimated life expectancy.
• Dilated optic nerve appearance. What is the amount, extent and location of the neuroretinal rim thinning, and are there any correlating glaucomatous disc hemorrhages and/or retinal nerve fiber layer defects?
• VF appearance after two reliable, repeatable tests. Does the VF correlate with the clinical exam, and what is the amount, extent and location (with respect to the central 10°) of the defect?
• Mean IOP readings after at least three readings at different times of the day.
• Appearance via gonioscopy. Is the glaucoma a primary or secondary form of open or closed angle glaucoma?
• Status of the fellow eye. Does the other eye have similar (or worse) damage; is it at risk for glaucomatous progression?

RE-EVALUATE THE RANGE

After subsequent structural and functional testing, target IOP range must be re-evaluated for each eye in each patient, based upon the patient’s:

• New test results.
• New ocular risk factors, such as narrowing of the angle in phakic patients.
• New systemic comorbidity risk factors, such as diabetes or systemic hypotension.
• Estimated rate of VF progression, based on previous test results.

Taking this list into account, the target IOP range should be lowered if the patient has:

• Longer residual life expectancy.
• Signs of advanced glaucomatous disease.
• Signs of reliable, rapid glaucomatous progression.
• Glaucomatous damage at lower IOPs.
• Thin corneas.
• Pseudoexfoliation glaucoma.

Of special consideration, the target IOP range may be sufficient (or may be adjusted upward) if systemic signs suggest poor health, increased frailty and decreased residual life expectancy.

STAY ON TARGET

Having an initial target guides our clinical decisions and treatment options. Staying on target helps preserve visual function for years to come, while maintaining quality of life. OM

REFERENCES

1. Kass MA, Heuer DK, Higginbotham EJ, et al. The ocular hypertension treatment study: a randomized trial determines that topical ocular hypotensive medication delays or prevents the onset of primary open-angle glaucoma. Arch Ophthalmol. 2002; 829: 701–13.
2. Heijl A, Leske MC, Bengtsson B, et al. Reduction of intraocular pressure and glaucoma progression: results from the Early Manifest Glaucoma Trial. Arch Ophthalmol. 2002; 10: 1268–1279.
3. Quigley HA. The number of people with glaucoma worldwide in 2010 and 2020. Br J Ophthalmol. 1996; 5: 389–393.
4. Sihota R, Angmo D, Ramaswamy D, Dada T. Simplifying “target” intraocular pressure for different stages of primary open-angle glaucoma and primary angle-closure glaucoma. Indian J Ophthalmol. 2018; 4: 495–505.

DR. LIFFERTH practices at Grossnickle Eye Center as a consultative optometrist with an emphasis in glaucoma management, and he is a member of the Optometric Glaucoma Society. For additional glaucoma cases, you can also follow Dr. Lifferth on his Instagram account: glaucomaqd. Disclosures: None. Email him at austinlifferth@yahoo.com.