FINDING THE BEST #TONOMETER FOR YOUR PRACTICE – IOP IN #OPTOMETRY & #OPHTHALMOLOGY
It’s easy to get lost while looking for the #BestTonometer as there are a few #tonometry options: applanation, handheld, desktop, noncontact, #airpuff, rebound, indentation, non-corneal, through the #eyelid / #transpalpebral, #scleral, pen-like #tonometers.
There is also a list of manufactures to pick from: HAAG-STREIT, 66Vision, #Canon, Cso, #DIATON, Huvitz, #Essilor, #Icare, Luneau, Kangjie, Keeler, #Kowa, Macro, Nidek, Oculus, #Reichert, Rexxam, Rodenstock, Swowei, #Tomey, Accutome, #Topcon, Ziemer just to name a few.
Each tonometry device has its benefits, advantages & limitations.
Tonometry devices can be broken up to 2 Main Categories:
Corneal Tonometry – where intraocular pressure (IOP) is measured by either indenting or applanating the cornea. Contact with the cornea and numbing drops might be required with some corneal tonometers (ex: Goldmann, Tonopen) and not others, such as Airpuff.Non-Corneal or Scleral Tonometry – this innovative tonometry category is represented by a single brand the Transpalpebral DIATON tonometer. Diaton presents an innovation due to its technique and ballistic principle, which is based on Newton’s second law of motions:
Fnet = m • a Diaton tonometer allows to measure IOP through the upper eyelid and sclera. Unlike all other cornea dependent tonometry devices, IOP with Diaton is not influenced by known and still unknown biometric properties of the cornea. #Pachymetry is not required to adjust the readings for the central corneal thickness (CCT), as with Diaton device, the operating principle and the technique completely eliminates the influence of the cornea. IOP is measured above the edge of the limbus, with Diaton tonometers tip placed on the upper #eyelid at #tarsus and sclera
Goldmann applanation tonometry is the gold standard for measuring IOP & most probably will continue to be so into the near future. However, its limitations were obvious from the start and include the substantial effects of several eye variables such as axial length, curvature, rigidity & #corneal thickness. Also, in some #eyes, especially those with corneal problems