Grating Visual Acuity in phakic, aphakic, and pseudophakic Poodles

Abstract

Objective To compare the grating visual acuity (VA) measured by visual evoked potentials (VEP) in phakic, aphakic, and pseudophakic Poodles. Animals studied Thirty‐six Poodle dogs aged from 4 to 14 years. Procedures Animals were allocated into three different groups according to their lens status: phakic group (n = 12), aphakic group (n = 12), and pseudophakic group (n = 12). Grating VA was measured in cycles/degree (cpd) in all animals using the electrodiagnosis system Roland RETIport® in a dark room without using any mydriatic, sedative, or anesthetic drugs. Results The mean grating VA in the phakic, aphakic, and pseudophakic groups was 5.9 ± 1.0 cpd (20/102—Snellen equivalent), 2.6 ± 0.7 cpd (20/231), and 5.2 ± 1.1 cpd (20/116), respectively. The VA from aphakic eyes was significantly lower when compared to the phakic and pseudophakic eyes (P < .05). There was no significant difference in VA between phakic and pseudophakic eyes. Conclusions The VEP is a useful tool for the evaluation of grating visual acuity in canines. The study showed that IOL implantation following phacoemulsification results in improved VA as measured by VEP compared to that of the aphakic eye and resulted in VA that was similar to that of the normal eye.

Clinical usefulness of transient visual evoked potentials (TVEPs) and steady-state visual evoked potentials (SSVEPs) results in blind dogs

“…TVEP and SSVEP examinations were performed without sedation or anesthesia after ERG. TVEPS and SSVEPs were recorded using an electrophysiological test unit (RETIport-Scan 21; Roland Consult, Brandenburg, Germany) according to a method described previously by Strain and Safatle [16,41]. Three needle electrodes were used to measure VEPs [3].…”

Quantifying visual acuity of Terrapene carolina triunguis utilizing optokinetic response

“…VEP utilizes electrodes attached to the tectal surface to record electrical activity from the optic tectum when a stimulus is presented in order to quantify visual acuity 7 . This method often requires opening the cranium and retracting parts of the dura to attach the electrodes or implanting electrodes through the skull, 8,9 though a recent study with dogs, uses a much less invasive method 10 . On the contrary, OKR is a physiologic response to an object moving out of the field of vision and the eye returning back to its original position.…”

“…7 This method often requires opening the cranium and retracting parts of the dura to attach the electrodes or implanting electrodes through the skull, 8,9 though a recent study with dogs, uses a much less invasive method. 10 On the contrary, OKR is a physiologic response to an object moving out of the field of vision and the eye returning back to its original position. This is accomplished by a combination of smooth pursuit and rapid saccade eye movements.…”

>b<Mensuração da acuidade visual de cães da raça Cavalier King Charles Spaniel pelo potencial visual evocado de varredura (PVEV)>/b<

“…A escolha do PVEV para a determinação da acuidade visual dos animais avaliados no presente estudo baseou-se nos bons resultados obtidos pelo método eletrofisiológico em bebês e crianças, quando comparados aos métodos comportamentais, tanto com relação à confiabilidade dos resultados, quanto à menor necessidade de cooperação, além de exigir um menor tempo de fixação ao exame (SALOMÃO et al, 2008). A comprovação da aplicabilidade da técnica em cães, por outros autores (MORENO-CARMONA et al, 2006;SAFATLE et al, 2020) aplicabilidade clínica e que, atualmente, provavelmente não passaria pela aprovação de alguma comissão de ética em uso de animais para experimentação. Um estudo mais recente da aplicação da técnica do PVEPR em gatos reporta não ter usado nenhum tipo de contenção química, valendose exclusivamente de contenção mecânica discreta, concordando com a metodologia aplicada no presente estudo (FERREIRA et al, 2015).…”

“…No presente estudo, os animais avaliados não tiveram a midríase medicamentosa induzida, obedecendo às recomendações da ISCEV (ODOM et al, 2016), com o objetivo de se evitar as aberrações esféricas, que comprometem a capacidade de resolução e consequentemente, de diferenciação dos estímulos de grades. Outros estudos envolvendo PVE de estímulos estruturados concordaram com este princípio e não utilizaram midríase em sua metodologia (MORENO-CARMONA et al, 2006;FERREIRA et al, 2015;SAFATLE et al, 2020).…”