Should Hypotensive Therapy Be Initiated for IOP of 26 mmHg?
The decision to initiate IOP-lowering therapy for a patient with IOP of 26 mmHg depends critically on the presence of additional risk factors, but given this elevated pressure level, treatment should be strongly considered, particularly if other risk factors are present. 1
Risk Stratification is Essential
An IOP of 26 mmHg places this patient in a higher-risk category that requires careful assessment:
- Patients with baseline IOP ≥26 mmHg AND thin central corneal thickness (CCT ≤555 μm) have a 36% risk of developing optic nerve damage during long-term follow-up 1
- In contrast, patients with IOP <24 mmHg and CCT >588 μm have only a 2% risk 1
- The Ocular Hypertension Treatment Study (OHTS) demonstrated that treatment reduced the 5-year risk of developing POAG from 9.5% to 4.4% 1, 2
Key Risk Factors That Should Prompt Treatment
Beyond the elevated IOP itself, assess for these established risk factors that would strengthen the indication for treatment: 1
- Older age
- Family history of glaucoma
- African-derived race or Latino/Hispanic ethnicity
- Thin central cornea (CCT <555 μm) - this is particularly important at IOP 26 mmHg
- Large cup-to-disc ratio
- Disc hemorrhage
- Diabetes mellitus
- Myopia
- Low ocular perfusion pressure
- Low systolic/diastolic blood pressure
- High pattern standard deviation on visual field testing
Use the OHTS Risk Calculator
Clinicians should utilize the validated OHTS risk calculator (available at https://ohts.wustl.edu/risk/) to determine the 5-year risk of progression to POAG 1. This calculator incorporates:
- Age
- Vertical cup-to-disc ratio
- Pattern standard deviation from visual field testing
- Central corneal thickness
- IOP level
Treatment Recommendations When Therapy is Indicated
If the decision is made to treat based on risk assessment, the target IOP should be at least 20% lower than baseline measurements 1. For an IOP of 26 mmHg, this means targeting approximately 21 mmHg or lower. However, if the starting pressure is markedly elevated (as 26 mmHg is), a 20% reduction may be insufficient, and a more aggressive target should be considered 1.
First-Line Medical Therapy
Prostaglandin analogs are the preferred initial medical therapy 1 because they:
- Provide the most efficacious IOP reduction (typically 6-8 mmHg) 3
- Are well-tolerated with minimal systemic side effects
- Require only once-daily dosing, improving adherence
- Demonstrated equivalent efficacy to timolol 0.5% twice daily in clinical trials 3
Alternative first-line options include: 1
- Topical beta-blockers (timolol 0.25-0.5%) - dosed once or twice daily, but avoid nighttime dosing due to nocturnal blood pressure reduction 4
- Alpha-2 adrenergic agonists (brimonidine) - though may cause fatigue/drowsiness 5
- Laser trabeculoplasty - should be considered as primary therapy, especially when medication adherence, cost, or side effects are concerns 1
Critical Caveats
Even if treatment is not initiated, long-term monitoring for development of glaucoma is absolutely essential 1. This includes:
- Serial optic nerve head and RNFL imaging 1
- Visual field testing to detect early functional changes 1
- Regular IOP measurements
Any evidence of optic nerve deterioration, RNFL loss, or visual field changes consistent with glaucomatous damage means the patient has converted to POAG and requires immediate treatment 1.
Shared Decision-Making
A thorough discussion must occur between physician and patient outlining the risks and benefits of treatment versus observation 1. This should include:
- The patient's individual risk profile
- Likelihood of long-term therapy if started
- Treatment side effects and costs
- Impact on quality of life over the patient's lifetime 1