Evaluation of Visual Evoked Potential in Psoriasis Vulgaris Patients in a Tertiary Care Centre

Psoriasis is an immunologically mediated, inflammatory disease with increased risk of painful and destructive arthritis, cardiovascular morbidity and psychosocial challenges. Psoriasis vulgaris is the most common form of psoriasis, seen in approximately 90% of patients. Besides skin, other regions widely involved are bone, cardiovascular system and eye. Psoriatic eye manifestations involve many of the structures of eye; from eyelid till optic nerve. Recording of Visual evoked potential helps in studying the integrity of optic nerve and its abnormality signifies demyelination. The concept Brain skin axis proposed in literature shows involvement of nervous system with immune mediated inflammatory pathway in Psoriasis. During intense inflammatory course, highly dense sensory nerves in plaques trigger the release of neuropeptides, targeting keratinocytes and further nerve damage. With this background, the present study was aimed to assess Optic pathway integrity by Visual Evoked Potential in patients of Psoriasis vulgaris. Materials and Methods: A Case control study was done with Institutional Ethics Committee approval and written informed consent on 100 plaque type psoriatic cases and 50 apparently healthy subjects as controls. Cases were divided into 2 groups based on their disease duration as I – new cases (1 to 5 years), II – old cases (6 to 10 years). Psoriatic patients treated with UVB and Methotrexate and with relapse of both gender of 15 to 35 years were included in the study. Patients with Diabetes Mellitus, Hypertension, any other chronic illness and autoimmune disease, severe forms of psoriasis, patients on oral steroids, and with H /O ocular diseases, eye surgery and neurological illness were excluded from the study. The mean Psoriasis Area Severity Index (PASI) was 16.09 ± 11.11. According to PASI score, the cases were categorised as <10 – mild; >11-20 – moderate; and>21 – severe. Clinical and ophthalmological examination was done for study participants. After proper instructions to patients for VEP procedure, VEP was recorded using Physiopac –NEURO PERFECT EMG 2000 SYSTEM. P100 latency of controls and cases was taken for analysis and analysed using SPSS 21.0 version. Results: There was increase in P100 latency of cases when compared to controls. P100 latency progressively increases as the severity of disease increases. Conclusion: Increased latency of P100 is a sign for demyelination. As this is seen in the present study, in psoriatic patients, there is a probability of optic nerve involvement during active state of disease. Keywords: Psoriasis, VEP, P100, PASI.