title: Intraoperative eye position after sub-Tenon's anesthesia for cataract surgery.
abstract: BACKGROUND
  To evaluate the incidence and extent of ocular deviation associated with sub-Tenon's anesthesia.
  
  
  METHODS
  Seventy-five consecutive patients undergoing routine phacoemulsification with sub-Tenon's anesthesia at the Eye Unit, Royal Gwent Hospital, were prospectively enrolled in this observational case series. The exclusion criteria were patients taking warfarin, or patients with preexisting ocular motility disorders, allergy to local anesthetics, or previous surgery for squint or retinal detachment. Eleven patients were subsequently excluded from the study group as they required additional anesthesia blocks before measurements were taken for ocular deviation. We injected 5 mL of a local anesthetic mixture of 2% lignocaine and 7.5 mg/mL levobupivacaine in the sub-Tenon's space in the inferonasal quadrant. Ocular deviation was assessed objectively by means of the Krimsky test. Forced duction tests were performed before and after anesthesia.
  
  
  RESULTS
  Hyperdeviation was documented in 49 (77%) eyes, exodeviation in 62 (97%), and hypodeviation in 6 (9.4%). No esodeviations were documented. Only 2 patients were orthophoric after anesthesia. Mean vertical deviation was 4.4 prism dioptres (PD) (SD 4.7 PD, 95% CI 3.2-5.5 PD, range 0-14 PD). Mean horizontal deviation was 19.5 (SD 9.6, 95% CI 17-22, range 0-50) PD. Forced duction test revealed no mechanical restriction before or after anesthesia.
  
  
  CONCLUSIONS
  This study suggests that there is an appreciable ocular deviation with sub-Tenon's anesthesia. Intraoperative ocular deviation may make certain procedures more difficult; therefore, we recommend a low threshold for an additional corrective block administered before surgery to rectify the deviation.
authors.affiliation: Eye Unit, Royal Gwent Hospital, Newport, UK. nishant6377@aol.com
authors.forename: Nishant
authors.initials: N
authors.lastname: Kumar
authors.forename: Sharmila
authors.initials: S
authors.lastname: Jivan
authors.forename: Vidya
authors.initials: V
authors.lastname: Pulpa
authors.forename: John
authors.initials: J
authors.lastname: Butler
authors.forename: Mohammed Younis
authors.initials: MY
authors.lastname: Khan
mesh_terms: D000772:Anesthesia, Local / Q000009:adverse effects*; D019162:Anesthetics, Combined / Q000008:administration & dosage*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D002045:Bupivacaine / Q000008:administration & dosage / Q000031:analogs & derivatives; D005205:Fascia / Q000187:drug effects*; D006801:Humans; D007431:Intraoperative Complications; D019654:Lens Implantation, Intraocular; D000077554:Levobupivacaine; D008012:Lidocaine / Q000008:administration & dosage; D018918:Phacoemulsification; D011446:Prospective Studies; D013285:Strabismus / Q000209:etiology*
chemical_list: D019162:Anesthetics, Combined; D000779:Anesthetics, Local; D008012:Lidocaine; D000077554:Levobupivacaine; D002045:Bupivacaine