title: Tono-Pen determination of intraocular pressure in patients with band keratopathy or glued cornea.
abstract: OBJECTIVE
  To evaluate the intraocular pressure (IOP) measurements in patients with band keratopathy or glued corneas obtained from affected and non-affected areas.
  
  
  METHODS
  15 patients with band keratopathy or glued corneas were prospectively recruited. When both eyes were affected, only the right eye was analysed. Tono-Pen readings of IOP were obtained sequentially from the affected and non-affected corneal surface. Additionally, Goldmann applanation tonometry was attempted.
  
  
  RESULTS
  Determination of IOP with the Tono-Pen was possible in all cases, while Goldmann tonometry was not performed in three patients because of severe corneal irregularities. The average of the Tono-Pen readings obtained from the affected cornea (34.8 (SD 14.0) mm Hg) was consistently and significantly higher (p < 0.001) than mean IOP obtained by the Tono-Pen from the non-affected area (14.8 (4.3) mm Hg). The average of Goldmann tonometry readings (14.4 (6.1) mm Hg) did not differ significantly from the Tono-Pen values obtained from the non-affected corneal area (p = 0.47) but was significantly lower than the Tono-Pen measurements obtained from the affected area (p < 0.001).
  
  
  CONCLUSIONS
  In patients with band keratopathy or glued corneas determination of IOP by Tono-Pen tonometry varies from affected to non-affected area. The Tono-Pen overestimates the level of IOP when it is applied to areas with band keratopathy or with glue.
authors.affiliation: Department of Ophthalmology, University Hospital, Queen's Medical Centre, University of Nottingham.
authors.forename: A
authors.initials: A
authors.lastname: Azuara-Blanco
authors.forename: T K
authors.initials: TK
authors.lastname: Bhojani
authors.forename: A R
authors.initials: AR
authors.lastname: Sarhan
authors.forename: C T
authors.initials: CT
authors.lastname: Pillai
authors.forename: H S
authors.initials: HS
authors.lastname: Dua
mesh_terms: D003316:Corneal Diseases / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D011446:Prospective Studies; D014065:Tonometry, Ocular / Q000295:instrumentation* / Q000379:methods