What is the best course of treatment for a patient with cystic fibrosis who presents with ocular hypertension?

Management of Ocular Hypertension (28 mmHg) in Cystic Fibrosis Patients

For a cystic fibrosis patient presenting with ocular hypertension of 28 mmHg, initiate IOP-lowering therapy immediately with topical medications, as this IOP level represents a significant risk factor for progression to glaucoma, particularly given the baseline ocular complications associated with CF.

Risk Assessment and Treatment Threshold

The decision to treat ocular hypertension at 28 mmHg is straightforward based on established risk stratification:

• Patients with baseline IOP of 26 mmHg or above have a 36% risk of developing optic nerve damage during long-term follow-up if untreated, compared to only 2% risk for those with IOP less than 24 mmHg 1
• The Ocular Hypertension Treatment Study (OHTS) demonstrated that treatment reduced progression from 9.5% to 4.5% over 5 years, though more than 90% of untreated patients did not progress 1
• At 28 mmHg, the risk-benefit analysis strongly favors treatment initiation given the substantial reduction in conversion risk 1

CF-Specific Ocular Considerations

Before initiating therapy, recognize that CF patients have unique baseline ocular characteristics that may influence management:

• CF patients demonstrate significantly decreased inferior-quadrant peripapillary retinal nerve fiber layer thickness compared to controls, suggesting potential baseline vulnerability of retinal ganglion cells 2
• Hypoxia from pulmonary disease may affect retinal ganglion cells, with correlations between visual field parameters and FEV1%, FVC%, and oxygen saturation 3
• No significant differences in baseline IOP or gonioscopic findings have been documented between CF patients and controls, indicating standard glaucoma management principles apply 2
• CF patients commonly have ocular surface disease including decreased tear break-up time and blepharitis, which may affect medication tolerance 2, 4

First-Line Pharmacologic Management

Initiate topical IOP-lowering therapy with prostaglandin analogs as first-line treatment, as these are the most effective single agents with once-daily dosing:

• Prostaglandin analogs provide superior IOP reduction and have the advantage of once-daily administration, improving adherence 1
• If prostaglandin analogs are contraindicated or not tolerated, combination therapy with brimonidine/timolol is an effective alternative 5
• Brimonidine/timolol combination provides 1-3 mmHg additional IOP reduction over brimonidine alone and 1-2 mmHg over timolol alone 5

Critical Contraindication Screening for CF Patients

Before prescribing beta-blockers (including timolol), carefully assess pulmonary status, as many CF patients have contraindications:

• Patients with bronchial asthma, severe chronic obstructive pulmonary disease, sinus bradycardia, second or third degree atrioventricular block, or cardiac failure should NOT receive beta-blocker containing drops 5
• Given that CF is characterized by chronic obstructive pulmonary disease and bronchiectasis 4, beta-blockers may be contraindicated in many CF patients
• If beta-blockers are contraindicated, use prostaglandin analogs, alpha-agonists alone, or carbonic anhydrase inhibitors 1

Addressing Ocular Surface Disease

Optimize ocular surface health before and during IOP-lowering therapy, as CF patients have high rates of surface disease:

• 56% of CF patients have abnormal tear break-up time, with all affected patients having concurrent blepharitis 2
• Treat blepharitis and meibomian gland dysfunction aggressively with lid hygiene and warm compresses 4
• Consider preservative-free formulations if available, as benzalkonium chloride can exacerbate surface disease 5
• Remove contact lenses prior to medication administration and wait 15 minutes before reinsertion 5

Monitoring Protocol

Establish intensive monitoring given the elevated baseline IOP and CF-related ocular vulnerabilities:

• Measure IOP within 4-6 weeks of treatment initiation to assess response 1
• Perform baseline and serial optic nerve head photography and computerized imaging of RNFL and macula to detect subtle structural changes 1
• Conduct automated visual field testing (30-2 or 24-2) at baseline and regularly thereafter, with consideration of 10-2 testing for central defects 1
• Monitor for progression of inferior RNFL thinning, which may occur more readily in CF patients 2
• Assess adherence carefully, as fatigue and drowsiness from medications like brimonidine may affect compliance 5

Target IOP and Treatment Adjustment

Aim for at least 20% IOP reduction from baseline (target ≤22 mmHg from 28 mmHg) to meaningfully reduce glaucoma risk:

• The OHTS demonstrated benefit with IOP reduction in the ocular hypertension range 1
• If target IOP is not achieved with monotherapy, add a second agent from a different class 1
• Laser trabeculoplasty can be considered as primary or adjunctive therapy 1

Long-Term Considerations

Commit to lifelong monitoring regardless of treatment response, as risk persists:

• Even with treatment, continued surveillance for optic nerve deterioration is essential 1
• Any evidence of optic nerve deterioration, RNFL loss, or glaucomatous visual field changes indicates conversion to primary open-angle glaucoma requiring more aggressive management 1
• Coordinate care with the patient's CF pulmonary team, particularly regarding medication contraindications and systemic disease progression 4

Common Pitfalls to Avoid

• Do not prescribe beta-blocker containing drops without confirming absence of pulmonary contraindications 5
• Do not rely on IOP measurement alone; structural and functional assessment is mandatory 1
• Do not assume normal adherence; CF patients may have reduced mental alertness from medications affecting compliance 5
• Do not ignore ocular surface disease, which can worsen with preserved medications and reduce treatment efficacy 2, 4