Sildenafil citrate, a selective oral phosphodiesterase 5 inhibitor, is a widely used drug for erectile dysfunction that acts by elevating cGMP levels and causing smooth muscle relaxation. It also has 10% activity against PDE6, a key enzyme in phototransduction cascade in the retina. Recent ocular imaging developments have further revealed the influence of sildenafil on ocular hemodynamics, particularly choroidal perfusion. Choroidal thickness is increased, and choroidal perfusion is also enhanced by autoregulatory mechanisms that are further dependent on age and microvascular abnormalities. Studies demonstrating high intraocular pressure via a “parallel pathway” from increased choroidal volume and blood flow to the ciliary body have challenged previous concepts. Another new observation is the effect of sildenafil on bipolar cells and cyclic-nucleotide gated channels. We discuss potential deleterious effects (central serous chorioretinopathy, glaucoma, ischemic optic neuropathy, and risks to recessive carriers of retinitis pigmentosa), potential beneficial effects (ameliorate choroidal ischemia, prevent thickening of Bruch membrane, and promote recovery of the ellipsoid zone) in macular degeneration, as well as potential drug interactions of sildenafil.

枸橼酸西地那非是一种选择性口服磷酸二酯酶 5 抑制剂，是一种广泛使用的勃起功能障碍药物，通过提高 cGMP 水平和引起平滑肌松弛起作用。它还对 PDE6 具有 10% 的活性，PDE6 是视网膜光转导级联中的关键酶。最近的眼部成像发展进一步揭示了西地那非对眼部血流动力学的影响，特别是脉络膜灌注。脉络膜厚度增加，并且脉络膜灌注也通过进一步依赖于年龄和微血管异常的自动调节机制而增强。研究表明，通过增加脉络膜体积和血液流向睫状体的“平行通路”产生高眼压，这对以前的概念提出了挑战。另一个新的观察结果是西地那非对双极细胞和环核苷酸门控通道的影响。我们讨论了黄斑部潜在的有害影响（中心性浆液性脉络膜视网膜病变、青光眼、缺血性视神经病变和隐性视网膜色素变性携带者的风险）、潜在的有益影响（改善脉络膜缺血、防止布鲁赫膜增厚和促进椭圆体区的恢复）变性，以及西地那非的潜在药物相互作用。