title: Randomised controlled trial on the effectiveness of lidocaine gel vs tetracaine drops as the sole topical anaesthetic agent for primary pterygium surgery.
abstract: OBJECTIVE
  To determine the effectiveness of lidocaine 2% gel vstetracaine 1% drops in primary pterygium surgery.
  
  
  METHODS
  This was a prospective, randomised controlled trial. Forty consecutive patients who had primary pterygium underwent surgical excision of primary pterygium and mitomycin C. Patients were randomised into two groups. Group 1 received tetracaine 1% drops and solcoseryl eye gel (Solco Basel AG, Switzerland). Group 2 received xylocaine 2% gel (lidocaine hydrochloride 2% gel, AstraZeneca, Sweden) topically and normal saline drops 0.9%. Additional tetracaine drops were given to patients who experienced pain preoperatively. The primary outcome was the pain experienced during and after surgery. Immediately after the operation, pain and discomfort scores were assessed by the patients and doctor using a 10-point linear analogue scale. The stages of the operation were divided into the following: stage 1-first incision, stage 2-pterygium body excision, stage 3-conjunctival suturing, and stage 4-immediate postoperative after patching.
  
  
  RESULTS
  There was no statistically significant difference in the mean pain scores experienced during pterygium excision (3.03+/-2.35 for the lidocaine group and 3.98+/-2.18 for the tetracaine group). However, for stage 3, there was a statistically significant difference in mean pain scores experienced during closure (P=0.03) (0.47+/-0.84 for the lidocaine gel group and 1.43+/-1.66 for the tetracaine group), with patients of group 2 experienced less pain. The mean number of additional drops required by the eyes in lidocaine gel group was also significantly (0.16+/-0.11) less than the tetracaine group (0.67+/-0.09, P=0.001).
  
  
  CONCLUSIONS
  Topical administration of lidocaine 2% gel or tetracaine 1 % drops are both effective anaesthetic agents for primary pterygium surgery and mitomycin C. However, lidocaine gel is superior to tetracaine eye drops and its application is more convenient with a less frequent application and a sustained duration of action.
authors.affiliation: Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, New Territories, Hong Kong. youngla@ha.org.hk
authors.forename: A L
authors.initials: AL
authors.lastname: Young
authors.forename: G Y S
authors.initials: GY
authors.lastname: Leung
authors.forename: L L
authors.initials: LL
authors.lastname: Cheng
authors.forename: T T Y
authors.initials: TT
authors.lastname: Lau
authors.forename: P T H
authors.initials: PT
authors.lastname: Lam
authors.forename: D S C
authors.initials: DS
authors.lastname: Lam
mesh_terms: D000287:Administration, Topical; D000328:Adult; D000368:Aged; D000779:Anesthetics, Local; D005260:Female; D005782:Gels; D006801:Humans; D008012:Lidocaine; D008297:Male; D008875:Middle Aged; D009883:Ophthalmic Solutions; D010146:Pain / Q000517:prevention & control*; D010147:Pain Measurement; D011446:Prospective Studies; D011625:Pterygium / Q000601:surgery*; D013748:Tetracaine
chemical_list: D000779:Anesthetics, Local; D005782:Gels; D009883:Ophthalmic Solutions; D013748:Tetracaine; D008012:Lidocaine