Phosphodiesterase Type-5 Inhibitors and Glaucoma

Area of Science:

• Ophthalmology
• Pharmacology
• Vascular Biology

Background:

• Phosphodiesterase type-5 (PDE5) inhibitors are used for erectile dysfunction and impact nitric oxide signaling, relevant to ocular vascular health.
• PDE5 is expressed in ocular tissues, prompting research into its effects on intraocular pressure (IOP), ocular blood flow, and glaucoma.
• Existing research on PDE5 inhibitors and ocular health necessitates a comprehensive review of their safety and potential therapeutic implications.

Purpose of the Study:

• To review clinical and experimental evidence on PDE5 inhibitors' effects on IOP, ocular perfusion, and glaucoma risk.
• To clarify the ophthalmic safety profile of PDE5 inhibitors.
• To explore potential therapeutic implications of PDE5 inhibitors in ocular conditions.

Main Methods:

• Systematic review of clinical trials and experimental studies.
• Analysis of data on intraocular pressure (IOP) changes.
• Evaluation of studies on ocular blood flow, including choroidal and retinal perfusion.
• Assessment of observational data and case reports related to glaucoma risk.

Main Results:

• Most studies show no clinically significant or sustained effect of PDE5 inhibitors on intraocular pressure (IOP).
• Evidence consistently indicates that PDE5 inhibition increases ocular blood flow, particularly in the choroid.
• Observational analyses suggest PDE5 inhibitor use may be associated with a reduced risk of glaucoma diagnosis.

Conclusions:

• PDE5 inhibitors have a neutral effect on IOP and enhance choroidal blood flow.
• PDE5 inhibitors may have a protective association with glaucoma.
• Further mechanistic and prospective studies are warranted to confirm these findings and explore therapeutic potential.