Refraction and electrophysiological visual evaluation in dogs undergoing phacoemulsification with intraocular lens implant

• Grant number: 14/19381-7
• Support Opportunities: Regular Research Grants
• Start date: August 01, 2015
• End date: July 31, 2017
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Clinics and Surgery
• Principal Investigator: Angélica de Mendonça Vaz Safatle
• Grantee: Angélica de Mendonça Vaz Safatle
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated researchers: Aline Adriana Bolzan ; Paula Yuri Sacai Munhoz

Abstract

Electrophysiological studies for visual acuity evaluation are often applied in human medicine for diagnostic and evaluation of numerous diseases. Sweep visual evoked potential (SVEP) is an objective method for visual acuity measurement that is nondependent of patient communication to perform. Therefore, the applicability in veterinary medicine became highly advantageous; however, still scarcely explored.The full field electroretinogram (ERG) is the only electrophysiological test commonly applied in clinical veterinary medicine at present. However, the vast existent breeds and species variability allows an immense future field of research and standardization. Additionally, others exams as ON and OFF electroretinogram (ON and OFF ERG), that measure the communication between photoreceptors and bipolar cells in the retina, have not yet been applied in veterinary medicine. A further understanding in animals exams is important not only to veterinary science, but also as a model to human medicine development.To standardize the ON and OFF ERG in dogs with cataract and to determinate the visual acuity in dogs undergoing cataract surgery with and without intraocular lens implant (IOL), twenty Poodle dogs, between 5 and 12 years old, will be selected and equally distributed in 2 groups: aphacic (without intraocular lens implant) and pseudophacic (with intraocular lens implant). Fifteen dogs of equal breed will be selected for the normal group, without any lens opacity. Full field ERG and ON and OFF ERG will be performed in the animals with cataracts and, 30 days after phacoemulsification surgery, the SVEP and ocular refractometry will be executed. The animals that belong to the normal group will perform the SVEP and ocular refractometry for comparison.The present study proposes to analyses the visual acuity difference, in an objective method, between phacic, aphacic and pseudophacic animals. The SVEP and ON and OFF ERG is an underexplored method in veterinary medicine and its application opens new opportunities to visual alterations diagnostic evolution in animals. (AU)