Vidalista 5 mg contains tadalafil, a PDE-5 inhibitor used for erectile dysfunction and sometimes other conditions. In rare cases, tadalafil can affect vision because PDE-5 enzymes are also present in the retina (the light-sensing tissue at the back of the eye). Possible reasons include: Effect on retinal blood flow and signaling: Tadalafil can slightly affect related chemical pathways involved in vision, which may rarely cause temporary changes such as: blurred vision changes in color perception (for example, a bluish tint) increased sensitivity to Vidalista 5 mg  Interaction with PDE-6: PDE-6 is an enzyme in the retina involved in visual processing. Although tadalafil is much more selective for PDE-5 than PDE-6 (more so than some other PDE-5 inhibitors), very small effects on retinal pathways may occur in susceptible individuals. Seek urgent medical attention if you experience: Sudden loss of vision in one or both eyes Sudden major changes in vision Sudden hearing loss or severe dizziness People with certain eye conditions (especially a history of non-arteritic anterior ischemic optic neuropathy, or NAION) should discuss tadalafil use with an eye specialist or doctor before taking it.