title: Subconjunctival lidocaine before laser treatment: a randomized trial.
abstract: OBJECTIVE
  The aim of the study was to determine whether subconjunctival anesthesia is effective at reducing pain associated with laser retinopexy.
  
  
  METHODS
  This was a single-center, prospective, patient-masked, randomized, controlled trial.
  
  
  METHODS
  In the primary study group, 65 patients were recruited. Thirty-two patients (32 eyes) received anesthetic injection, and 33 patients (33 eyes) received the sham injection. The crossover study group consisted of 28 patients (56 eyes).
  
  
  METHODS
  Between February 2008 and April 2008, all patients who were consecutively booked to undergo panretinal photocoagulation (PRP) or peripheral laser retinopexy (PLR) were invited to participate in the study. Patients were randomized to receive subconjunctival lidocaine injection or a sham injection before their intended laser retinal treatment. These patients were defined as our primary study group. Patients who required a second laser treatment received the opposite injection in a masked fashion before laser retinal treatment. These patients were defined as our crossover group. Patients in both the primary study group and the crossover group were masked to the treatment given. After the laser treatment, patients completed a pain questionnaire.
  
  
  METHODS
  The primary outcome was incidence of pain. The secondary outcome was severity of pain.
  
  
  RESULTS
  Primary study group: In the anesthetic treatment group, 19 patients (59%) experienced pain compared with 32 patients (97%) in the sham treatment group (P<0.001). Among the patients who did experience pain, the average pain score was 3.6 in the anesthetic treatment group and 4.1 in the sham treatment group (P=0.55). Crossover study group: In the anesthetic treatment group, 12 patients (43%) experienced pain compared with 28 patients (100%) in the sham treatment group (P<0.001). In patients who did experience pain, the average pain score was 3.3 in the anesthetic treatment group and 4.6 in the sham treatment group. Twenty patients (71%) preferred anesthetic to sham treatments, 1 patient (4%) preferred sham over anesthetic, and 7 patients (25%) thought both laser treatments were the same.
  
  
  CONCLUSIONS
  Subconjunctival 2% lidocaine significantly reduces the incidence of pain in patients who receive PRP or PLR.
authors.affiliation: Department of Ophthalmology, Lincoln County Hospital, Lincoln, UK.
authors.forename: Paul E
authors.initials: PE
authors.lastname: Tesha
authors.forename: Louis R
authors.initials: LR
authors.lastname: Giavedoni
authors.forename: Alan R
authors.initials: AR
authors.lastname: Berger
authors.forename: Filiberto
authors.initials: F
authors.lastname: Altomare
authors.forename: David R
authors.initials: DR
authors.lastname: Chow
authors.forename: Eduardo V
authors.initials: EV
authors.lastname: Navajas
authors.forename: Pradeepa
authors.initials: P
authors.lastname: Yoganathan
authors.forename: David T
authors.initials: DT
authors.lastname: Wong
authors.forename: Andre
authors.initials: A
authors.lastname: Principe
mesh_terms: D000698:Analgesia / Q000379:methods; D000772:Anesthesia, Local / Q000379:methods*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D003228:Conjunctiva; D018592:Cross-Over Studies; D017679:Cryotherapy; D003930:Diabetic Retinopathy / Q000601:surgery; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007267:Injections; D017075:Laser Coagulation; D008012:Lidocaine / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D010149:Postoperative Pain / Q000175:diagnosis / Q000517:prevention & control*; D011446:Prospective Studies; D012163:Retinal Detachment / Q000601:surgery; D012167:Retinal Perforations / Q000601:surgery; D011795:Surveys and Questionnaires
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine