title: Differences in Corneal Parameters Between Affected and Normal Contralateral Eyes in Patients With Hemifacial Spasm Treated With Botulinum Toxin-A: Outcomes During One Complete Treatment Cycle.
abstract: OBJECTIVE
  To investigate possible temporary differences in corneal topographic parameters between affected and normal eyes in patients with hemifacial spasm (HFS) treated with botulinum toxin-A (BTX-A), over the course of 1 treatment cycle.
  
  
  METHODS
  This prospective study evaluated corneal topographic differences between affected and normal contralateral eyes during a 4-month period in patients with HFS treated with BTX-A (the duration of action of BTX-A for HFS ranges from 2 to 4 months). Corneal topographic analysis was performed using a conventional topographer (Atlas; Carl Zeiss Meditec, Dublin, CA). Steep K and astigmatism measurements were evaluated before BTX-A application and after 15 days and 2, 3, and 4 months.
  
  
  RESULTS
  Twenty-four patients (16 women and 8 men) were evaluated. Steep K [46.9 ± 3.6 diopters (D)] and astigmatism values (2.6 ± 2.5 D) were significantly higher in affected eyes of HFS patients than in nonaffected eyes (45.0 ± 1.4 D and 0.9 ± 0.6 D) before treatment (P = 0.001 for steep K and P = 0.0003 for astigmatism). Astigmatism values also showed significant differences between the affected eye (1.4 ± 0.8 D) and nonaffected eye (0.9 ± 0.6 D) at 4 months (P = 0.006), whereas steep K showed significant differences between both eyes at 15 days (affected eye: 45.6 ± 1.5 D, nonaffected eye: 45.0 ± 1.4 D, P = 0.008), 3 months (affected eye: 45.6 ± 1.8 D, nonaffected eye: 45.1 ± 1.3 D, P = 0.03) and 4 months (affected eye: 45.8 ± 1.2 D, nonaffected eye: 45.1 ± 1.4 D, P = 0.003) after treatment.
  
  
  CONCLUSIONS
  The differences in steep K, and especially in astigmatism values, between eyes tended to reduce during the period of action of BTX-A. At 4 months, when the BTX-A effect is considered to be over or very reduced, a significant difference between eyes for both parameters was noted again.
authors.affiliation: Department of Ophthalmology and Visual Sciences, Paulista School of Medicine, Federal University of Sao Paulo/UNIFESP, Sao Paulo, Brazil.
authors.forename: Teissy
authors.initials: T
authors.lastname: Osaki
authors.forename: Midori H
authors.initials: MH
authors.lastname: Osaki
authors.forename: Tammy H
authors.initials: TH
authors.lastname: Osaki
authors.forename: Flavio E
authors.initials: FE
authors.lastname: Hirai
authors.forename: Mauro
authors.initials: M
authors.lastname: Campos
mesh_terms: D065087:Acetylcholine Release Inhibitors / Q000627:therapeutic use*; D000368:Aged; D000369:Aged, 80 and over; D001251:Astigmatism / Q000503:physiopathology*; D019274:Botulinum Toxins, Type A / Q000627:therapeutic use*; D003315:Cornea / Q000503:physiopathology*; D019781:Corneal Topography; D005143:Eyelids / Q000503:physiopathology*; D005260:Female; D019569:Hemifacial Spasm / Q000188:drug therapy* / Q000503:physiopathology; D006801:Humans; D007273:Injections, Intramuscular; D008297:Male; D008875:Middle Aged; D009801:Oculomotor Muscles / Q000187:drug effects; D011446:Prospective Studies; D014792:Visual Acuity / Q000502:physiology
chemical_list: D065087:Acetylcholine Release Inhibitors; D019274:Botulinum Toxins, Type A