In the practice I work in, I only use a Perkins tonometer
, but after a few attempts, it became easy.
Intra ocular pressure was recorded using Perkins tonometer
. Posterior segment evaluation was done after dilating with tropicamide- phenylephrine eye drops using indirect ophthalmoscope (Keeler), 90D panfundoscopy lens and goldmann 3 mirror examinations.
First, the Tono-Pen XL tonometer (Medtronic Solan, Jacksonville, FL, USA) was used, and the mean was calculated (MAGGS, 2008); then, the Perkins tonometer
(Clement Clarke, Harlow, UK) was used, and the mean was calculated and multiplied by 10 (ANDRADE et al., 2009; ANDRADE et al., 2011).
The best method is to employ an Alcon pneumatic or Perkins tonometer
for measuring IOP in subjects either sitting or lying down4.
'For instance it misinterprets the guidelines on the use of the Perkins tonometer
. The clarification states "Where GAT is not practicable for whatever reason then the guidelines suggest Perkins hand-held tonometry as an acceptable alternative", while the guidelines themselves are quite specific about the circumstances when Perkins can be used: "Hand-held methods of tonometry such as Perkins may be useful in a case finding/screening scenario where a person may have difficulty being examined on a slit lamp (for example with curvature of the spine)".'
Obviously many optometrists use a Perkins tonometer
, and we asked specifically that the Perkins tonometer
be included in the guidelines."
(8) For the purposes of this discussion, the Perkins tonometer
will be considered equivalent to GAT.
Compared to GAT, Perkins tonometers
have lower magnification and dimmer illumination; both of these factors could considerably reduce the visibility of the inner edge of the mires, thus causing an underestimation of IOP measurements.
are essentially hand-held versions of the gold-standard Goldmann applanation devices, but require topical anaesthetic and fluorescein instillation, along with appropriate disposal or sterilisation of probes.
Lots of practices have Perkins tonometers
but not Goldmann and to exclude them would reduce the effectiveness of a refinement scheme.