title: Change in flash visual evoked potentials in New Zealand albino rabbits after sub-tenon's anesthesia.
abstract: BACKGROUND
  The occurrence of amaurosis during ophthalmic anesthesia is well known. The reason for this manifestation has not been studied.
  
  
  OBJECTIVE
  To investigate the effect of sub-tenon's anesthesia on visual conduction in rabbit eyes.
  
  
  METHODS
  Fifteen right eyes of 15 New Zealand albino rabbits were included. 2% lidocaine hydrochloride and 0.75% bupivacaine hydrochloride (1 ml, 1:1 mixture) was injected in the sub-tenon's space of 8 eyes while the control group (n = 7) was injected with 1 ml physiological saline. Flash visual evoked potentials (FVEP) were performed with Roland reti-scan system before and, 5 min, 15 min, and 5 days after injection. The natural pupillary diameter and minimal pupillary diameter with light reflex were recorded.
  
  
  RESULTS
  In the anesthesia group, N1 latency, P1 latency, and P1 amplitude were 17.13 ± 1.13 ms, 28.25 ± 1.83 ms, 13.45 ± 4.36 μv respectively before injection; 21.75 ± 3.06 ms, 29.63 ± 2.67 ms, 7.24 ± 4.64 μv at 5 min after injection; 22.25 ± 1.39 ms, 29.50 ± 2.51 ms, 7.54 ± 4.47 μv at 15 min after injection, and, 17.75 ± 0.71 ms, 28.13 ± 2.42 ms, 13.17 ± 4.08 μv 5 days after injection. When compared with baseline, N1 latency at 5 min and 15 min after injection showed prolongation (p = 0.019 and p = 0.001, respectively). Likewise, P1 amplitude decreased at 5 min and 15 min after injection (p < 0.001, p < 0.001, respectively). Both N1 latency and P1 amplitude recovered 5 days after the injection. Pupillary light reflex (PLR) constriction amplitude was 35.42% and 0.00% before and at 5 min after injection (p = 0.012). After 5 days it recovered to 33.33%. The FVEP and PLR constriction amplitude did not change significantly after injection in the control group.
  
  
  CONCLUSIONS
  Sub-tenon's anesthesia was associated with changes in the FVEP and pupullary light reflex in rabbit eyes in our study.
  
  
  CONCLUSIONS
  The data from this study suggested that sub-tenon's anesthesia could reversibly block visual conduction in rabbit's eyes.
authors.affiliation: a Joint Shantou International Eye Center, Shantou University & the Chinese University of Hong Kong , Shantou , China , and.
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Wu
authors.affiliation: b Department of Ophthalmology & Visual Sciences , The Chinese University of Hong Kong , Shatin , Hong Kong.
authors.forename: Vishal
authors.initials: V
authors.lastname: Jhanji
authors.affiliation: a Joint Shantou International Eye Center, Shantou University & the Chinese University of Hong Kong , Shantou , China , and.
authors.forename: Haoyu
authors.initials: H
authors.lastname: Chen
authors.affiliation: a Joint Shantou International Eye Center, Shantou University & the Chinese University of Hong Kong , Shantou , China , and.
authors.forename: Hongjie
authors.initials: H
authors.lastname: Lin
authors.affiliation: a Joint Shantou International Eye Center, Shantou University & the Chinese University of Hong Kong , Shantou , China , and.
authors.forename: Guihua
authors.initials: G
authors.lastname: Zhang
authors.affiliation: b Department of Ophthalmology & Visual Sciences , The Chinese University of Hong Kong , Shatin , Hong Kong.
authors.forename: Marten
authors.initials: M
authors.lastname: Brelen
authors.affiliation: a Joint Shantou International Eye Center, Shantou University & the Chinese University of Hong Kong , Shantou , China , and.
authors.forename: Weiqi
authors.initials: W
authors.lastname: Chen
mesh_terms: D000772:Anesthesia, Local / Q000009:adverse effects* / Q000379:methods; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000009:adverse effects*; D000818:Animals; D001766:Blindness / Q000139:chemically induced* / Q000503:physiopathology; D002045:Bupivacaine / Q000008:administration & dosage / Q000009:adverse effects; D005074:Evoked Potentials, Visual / Q000187:drug effects*; D005260:Female; D056965:Injections, Intraocular; D008012:Lidocaine / Q000008:administration & dosage / Q000009:adverse effects; D009407:Nerve Block / Q000009:adverse effects* / Q000379:methods; D011817:Rabbits; D012025:Reflex, Pupillary / Q000187:drug effects*; D058475:Tenon Capsule
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine; D002045:Bupivacaine
keywords: Ophthalmic anesthesia; sub-tenon’s anesthesia; visual potential