This case was reported in a literature article and described the occurrence of optic neuritis in a 27-year-old male patient who received DTPa-IPV (DTPa-IPV) for prophylaxis. Additional patient notes included the patient was a previously healthy and had no significant past medical history. On an unknown date, the patient received DTPa-IPV at an unknown dose. On an unknown date, 1 day after receiving DTPa-IPV, the patient experienced optic neuritis (serious criteria hospitalization and GSK medically significant), headache (serious criteria hospitalization), painful eye movement (serious criteria hospitalization), blurred vision (serious criteria hospitalization), hyperemia eye (serious criteria hospitalization), microaneurysms (serious criteria hospitalization), vision decreased (serious criteria hospitalization), relative afferent pupillary defect (serious criteria hospitalization), dyschromatopsia (serious criteria hospitalization) and optic nerve edema (serious criteria hospitalization and GSK medically significant). The patient was treated with SOLU-MEDROL and prednisone. On an unknown date, the outcome of the optic neuritis, headache, painful eye movement, blurred vision, hyperemia eye, microaneurysms, vision decreased, relative afferent pupillary defect and dyschromatopsia were recovered/resolved and the outcome of the optic nerve edema was unknown. The reporter considered the optic neuritis, headache, painful eye movement, blurred vision, hyperemia eye, microaneurysms, vision decreased, relative afferent pupillary defect, dyschromatopsia and optic nerve edema to be related to DTPa-IPV. Additional information was provided. This case was reported in a literature article and described the occurrence of Optic Neuritis in a 27-year-old patient who was vaccinated with unspecified diphtheria, tetanus, pertussis, and inactivated polio-virus combined vaccine (DTaP-IPV) vaccine (manufacturer unknown) for prophylaxis. The patient was a previously healthy man. He had no significant past medical history. No information on patient's family history or concomitant medication or concurrent condition was provided. On an unspecified date, the patient received unspecified DTaP-IPV vaccine (administration route and site unspecified; dosages unknown; batch number not provided). The patient was 26 or 27-year old at the time of vaccination. On an unspecified date in 2013, the patient presented to an emergency department with a 5-day history of headache, pain with ocular movements, and intermittent blurred vision starting 1 day after immunization. Magnetic resonance imaging and a magnetic resonance venogram of his brain were unremarkable. A lumbar puncture revealed a normal opening pressure and cerebrospinal fluid studies were positive for myelin basic protein but negative for oligoclonal bands and neuromyelitis optica autoantibody serology. On examination, his best corrected vision was 20/100 in his right eye and 20/70 in his left eye. Intraocular pressures, pupil examination, ocular alignment, and extraocular movements were normal. Confrontational visual fields were restricted in both eyes. Posterior segment examination showed optic nerve swelling and hyperaemia in both eyes and two microaneurysms in the mid periphery of his left eye. No evidence of vitritis, retinal vasculitis, or choroiditis was seen in either eye. Serum laboratory testing showed elevated glycated haemoglobin (A1C) at 6.9%, aspartate aminotransferase (AST), and alanine aminotransferase (ALT). Other liver tests including bilirubin, alkaline phosphatase, and hepatitis serologies were normal. Tests for infectious and inflammatory aetiologies including angiotensin-converting enzyme (ACE), lysozyme, antinuclear antibody (ANA), cytoplasmic antineutrophil cytoplasmic antibodies (c-ANCA), perinuclear antineutrophil cytoplasmic antibodies (p-ANCA), lupus panel, rapid plasma reagin (RPR), fluorescent treponemal antibody absorption (FTA-ABS), chest X-ray, and QuantiFERON Gold assay, which were normal. Over the next 5 days, his vision declined to counting fingers at 30.5 cm (1 foot) in both eyes. A relative afferent pupil defect and dyschromatopsia developed on the left. Automated Humphrey visual field (HVF) testing demonstrated global depression in both eyes. He was diagnosed as having DTaP-IPV vaccination-related optic neuritis and started on intravenously administered SOLU-MEDROL on 11 September 2013. 1 week later, his headache resolved, and vision improved to 20/20 in his right eye and 20/25 in his left eye with less optic nerve hyperaemia and swelling. He was discharged on a prednisone taper and an orally administered diabetic medication. One month later, his vision improved to 20/20 with resolution of the optic neuritis without residual visual field deficit in both eyes. This case has been considered serious due to hospitalization. The author considered the event of optic neuritis related to unspecified DTaP-IPV vaccine. The author concluded, "Although the association between immunizations and the onset of CNS demyelinating conditions is well documented, this report, to the best of our knowledge, is the first case of optic neuritis following DTaP-IPV vaccination. Inclusion of this case report in the medical community will allow for broader understanding of possible conditions that may present shortly after receipt of vaccination." Lab Comments: Laboratory tests were performed on unspecified dates in 2013. Magnetic resonance imaging and a magnetic resonance venogram of his brain were unremarkable. Cerebrospinal fluid studies were positive for myelin basic protein but negative for oligoclonal bands and neuromyelitis optica autoantibody serology. Corrected vision was 20/100 in his right eye and 20/70 in his left eye. Pupil examination, ocular alignment and extraocular movements were normal. Confrontational visual fields were restricted in both eyes. Posterior segment examination showed optic nerve swelling and hyperaemia in both eyes and two microaneurysms in the mid periphery of his left eye. Hepatitis serologies were normal. No evidence of vitritis, retinal vasculitis, or choroiditis was seen in either eye. Tests for infectious and inflammatory aetiologies including lupus panel, fluorescent treponemal antibody absorption, QuantiFERON Gold assay, were normal. Automated Humphrey visual field (HVF) testing demonstrated global depression in both eyes. Over the next 5 days, his vision declined to counting fingers at 30.5 cm (1 foot) in both eyes. A relative afferent pupil defect and dyschromatopsia developed on the left. Vision improved to 20/20 in his right eye and 20/25 in his left eye with less optic nerve hyperaemia and swelling. One month later, his vision improved to 20/20 with resolution of the optic neuritis without residual visual field deficit in both eyes.