{"id":"43e19949-99b9-5cdd-8865-f3c3ccc63c38","stable_key":"252872b9-233f-5692-b72b-c8930ba0cfb7:sil-transient-visual-disturbance","predicate":"causes","statement":"Sildenafil has a mild inhibitory effect on PDE6, which controls the level of cyclic guanosine monophosphate in the retina, and it may cause a perception of bluish haze or increased light sensitivity in some patients, with long-term retinal damage not reported although long-term electroretinographic studies have not been performed; the drug causes a mild lowering of blood pressure and is contraindicated in patients taking any form of nitrate medication.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"positive","is_public":true,"mechanism_event_id":"d7c9a9f6-6c31-5843-9359-05d47e2277ee","mechanism_event_label":"The colour disturbance some people notice is the same drug reaching the retinal version of the enzyme.","subject":{"id":"fe62cf8d-5f89-5e19-bc36-03ad3c9063b7","slug":"sildenafil","display_name":"Sildenafil","entity_type_key":"drug"},"object":{"id":"85705a0f-9bb4-52cd-abd2-c0a2dedf7d39","slug":"colour-vision-disturbance","display_name":"Transient colour vision disturbance and increased light sensitivity","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"d7c9a9f6-6c31-5843-9359-05d47e2277ee","stable_key":"252872b9-233f-5692-b72b-c8930ba0cfb7:sil-transient-visual-disturbance-event","event_type":"observed_intervention","label":"The colour disturbance some people notice is the same drug reaching the retinal version of the enzyme.","description":"Sildenafil has a mild inhibitory effect on PDE6, which controls the level of cyclic guanosine monophosphate in the retina, and it may cause a perception of bluish haze or increased light sensitivity in some patients, with long-term retinal damage not reported although long-term electroretinographic studies have not been performed; the drug causes a mild lowering of blood pressure and is contraindicated in patients taking any form of nitrate medication.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"3a7633ec-a265-5827-988d-eed442633b39","slug":"pde6-family","display_name":"Phosphodiesterase 6 family","entity_type_key":"protein_family"},"role":"off_target_enzyme","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"6d2f509b-3a5b-5a38-b3e7-b148581edec9","slug":"cgmp","display_name":"Cyclic guanosine monophosphate","entity_type_key":"small_molecule"},"role":"retinal_messenger","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"f95f0052-92da-554e-affc-e14186abfa98","slug":"electroretinogram","display_name":"The electroretinogram a-wave and b-wave","entity_type_key":"cellular_process"},"role":"unmeasured_long_term","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"fe62cf8d-5f89-5e19-bc36-03ad3c9063b7","slug":"sildenafil","display_name":"Sildenafil","entity_type_key":"drug"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"85705a0f-9bb4-52cd-abd2-c0a2dedf7d39","slug":"colour-vision-disturbance","display_name":"Transient colour vision disturbance and increased light sensitivity","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/sildenafil-research/10541153.abstract.txt\", \"locator\": \"Indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"8c5d3c6e9d606690e6cc997086ded515a4e9f785561a7fc58fdbfb75b3f0a79a\", \"start_char\": 0, \"end_char\": 1024, \"text_sha256\": \"8c5d3c6e9d606690e6cc997086ded515a4e9f785561a7fc58fdbfb75b3f0a79a\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Review of the ophthalmic profile shortly after marketing approval","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Reported visual effects at therapeutic doses","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"A short review written in the first year of marketing. It records explicitly that long-term electroretinographic studies had not been performed, which is the limitation that matters for the claim.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Sildenafil research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from its N-desmethyl metabolite and its target enzyme from the homologous retinal PDE6.","comparator":null,"unit":null,"notes":"","entity":{"slug":"sildenafil","display_name":"Sildenafil","entity_type_key":"drug"}},{"dimension":"organism","value_text":"Human","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"The colour disturbance some people notice is the same drug reaching the retinal version of the enzyme.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[sil-p10541153] Sildenafil (Viagra) and ophthalmology. (1999). https://pubmed.ncbi.nlm.nih.gov/10541153/ DOI: 10.1016/s0039-6257(99)00079-x","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Retina","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"3f0ccdc1-69fd-5c23-bb6e-9f8ac89247aa","evidence_kind":"source_excerpt","locator":"Lines 483-494","start_line":483,"end_line":494,"excerpt":"### sil-transient-visual-disturbance\nSildenafil has a mild inhibitory effect on PDE6, which controls the level of cyclic guanosine monophosphate in the retina, and it may cause a perception of bluish haze or increased light sensitivity in some patients, with long-term retinal damage not reported although long-term electroretinographic studies have not been performed; the drug causes a mild lowering of blood pressure and is contraindicated in patients taking any form of nitrate medication.\nCondition category: normal\nnutrient_topic: Sildenafil research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from its N-desmethyl metabolite and its target enzyme from the homologous retinal PDE6.\nplain_language: The colour disturbance some people notice is the same drug reaching the retinal version of the enzyme.\norganism: Human\ntissue_or_cell_type: Retina\nexperimental_model: Review of the ophthalmic profile shortly after marketing approval\nlimitations: A short review written in the first year of marketing. It records explicitly that long-term electroretinographic studies had not been performed, which is the limitation that matters for the claim.\nexposure: Reported visual effects at therapeutic doses\nevidence_span: {\"source_cache\": \"artifacts/sildenafil-research/10541153.abstract.txt\", \"locator\": \"Indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"8c5d3c6e9d606690e6cc997086ded515a4e9f785561a7fc58fdbfb75b3f0a79a\", \"start_char\": 0, \"end_char\": 1024, \"text_sha256\": \"8c5d3c6e9d606690e6cc997086ded515a4e9f785561a7fc58fdbfb75b3f0a79a\"}\n[sil-p10541153] Sildenafil (Viagra) and ophthalmology. (1999). https://pubmed.ncbi.nlm.nih.gov/10541153/ DOI: 10.1016/s0039-6257(99)00079-x","model_system":"Review of the ophthalmic profile shortly after marketing approval","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [sil-p10541153] Sildenafil (Viagra) and ophthalmology. (1999). https://pubmed.ncbi.nlm.nih.gov/10541153/ DOI: 10.1016/s0039-6257(99)00079-x","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"c6c2a590-1f8f-5fac-b2c7-3aae0440b9fd","stable_key":"import-252872b9-233f-5692-b72b-c8930ba0cfb7","title":"Sildenafil: the enzyme it occupies instead of the substrate, why it cannot start a signal it can only preserve, the organic nitrate interaction that follows from that, the homologous retinal enzyme ten-fold away, and the pulmonary circulation where the same mechanism became a second indication (2026-09-22)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text.","file_path":"","sha256":"bc81793d20d20d2eaad9cb530b70695d8d8778a3d7136e24715ac3369b939953","revision_id":"301732e1-2446-5b67-b3bd-580164b85b05","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}