II. Indications

III. Techniques: Applanation Tonometry - Intraocular Pressure measurement

  1. Background
    1. Applanation devices measure the amount of pressure needed to flatten a small portion of the Cornea
    2. Apply Topical Eye Anesthetic to Cornea before testing
  2. Goldmann Tonometer
    1. Slit-lamp based device that offers most accurate Intraocular Pressure measurement
  3. Portable electronic Applanation Tonometers (e.g. Tono-Pen, Accupen)
    1. Accurate Tonometry alternative to the Goldmann Tonometer
  4. Non-contact Tonometers (air-puff)
    1. Least accurate Tonometry method, but no topical anesthetic needed
  5. Schiotz (older, manual method, rarely used in U.S.)
    1. Requires a skilled, practiced clinician to use accurately
    2. Scale <3.5 (5.5g plunger) recheck with 7.5g plunger
    3. Scale <6.0 (7.5g plunger) recheck with 10g plunger
    4. Scale <8.5 (10g plunger) recheck with 15g plunger
    5. Scale <11.0 (15g plunger)

IV. Interpretation

  1. Normal Intraocular Pressure
    1. Intraocular Pressure 8 to 21 mmHg
  2. Elevated Intraocular Pressure
    1. Intraocular Pressure > 21.5 mmHg

V. Exam: Less accurate methods to estimate Intraocular Pressure

  1. Eye pressure applied through upper Eyelid
    1. Firmer eye suggests a higher Intraocular Pressure
  2. Anterior Chamber Depth
    1. Penlight illumination of anterior chamber
    2. Normal
      1. Illumination from lateral side lights entire iris
    3. Abnormal (increased pressure)
      1. Iris is bowed forward and nasal side is in shadow
      2. Nasal iris is not illuminated

VI. References

  1. Trobe (2012) Physician's Guide to Eye Care, AAO, p. 28

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Ontology: Physiologic Intraocular Pressure (C0021888)

Definition (MSH) The pressure of the fluids in the eye.
Definition (CSP) pressure of the fluids of the eye against the tunics; produced by continual renewal of the fluids within the interior of the eye.
Concepts Organ or Tissue Function (T042)
MSH D007429
SnomedCT 363938006, 251737001, 41633001
LNC LP96294-1, MTHU034775
English Intraocular Pressure, Intraocular Pressures, Ocular Tension, Ocular Tensions, Pressure, Intraocular, Pressures, Intraocular, Tensions, Ocular, Tension, Ocular, intraocular pressure, Ocular tension, Physiologic Intraocular Pressure, ocular tension, pressure in eye, intraocular pressures, Ocular tension (observable entity), Intraocular pressure, IOP - Intraocular pressure, Intraocular pressure (observable entity), Intraocular pressure, NOS, Intraocular pressure (observable)-RETIRED
Swedish Ögontryck
Czech nitrooční tlak
Finnish Silmänpaine
Russian VNUTRIGLAZNOE DAVLENIE, GLAZNOE DAVLENIE, ВНУТРИГЛАЗНОЕ ДАВЛЕНИЕ, ГЛАЗНОЕ ДАВЛЕНИЕ
Japanese 眼圧, 眼内圧
Italian Tensione oculare, Pressione intraoculare
Croatian INTRAOKULARNI TLAK
Polish Ciśnienie śródoczne, Ciśnienie śródgałkowe, Ciśnienie wewnątrzgałkowe
Portuguese Pressão Intraocular, Tensão Ocular
Norwegian Øyetrykk, Intraokulært trykk
Spanish presión intraocular (entidad observable), presión intraocular, Tensión Ocular, Presión Intraocular
French Ophtalmotonus, Pression intra-oculaire, Tension oculaire, Tonus oculaire
German Augendruck, Intraokularer Druck
Dutch Druk, intraoculaire, Intraoculaire druk, Oogdruk

Ontology: Tonometry (C0040420)

Definition (MSH) Measurement of the pressure or tension of liquids or gases with a tonometer. It has been developed to measure pressure in the EYE; the BLOOD VESSELS; and the STOMACH.
Concepts Diagnostic Procedure (T060)
MSH D008365
ICD9 89.11
ICD10 92016-00
SnomedCT 164732007, 141903009, 164729009
LNC LP32273-2, LP76227-5
English Tonometry NOS, tonometry (procedure), tonometry, Tonometry NOS (procedure), Tonometry (procedure), Tonometry
Portuguese Tonometria
Spanish Tonometría, tonometría, SAI, tonometría, SAI (procedimiento), tonometría (procedimiento), tonometría
German Tonometrie, Augeninnendruck-Messung
French Tonométrie
Czech tonometrie
Italian Tonometria
Norwegian Tonometri, Måling av øyetrykket, Øyetrykksmåling
Dutch Tonometrie

Ontology: Tonometer (C0183969)

Definition (UMD) Measuring instruments designed to determine intraocular pressure. These instruments may use several different techniques: applanation, indentation, and noncontact (air puff) tonometry. Tonometers can be attached to a slit lamp, and portable and handheld devices are also available. Ophthalmic tonometers are mainly intended for assessing ocular hypertension (intraocular pressure between 10 and 24 mm Hg is considered normal), usually to screen patients for glaucoma.
Definition (NCI) A handheld instrument that provides a measurement of intraocular pressure.
Concepts Medical Device (T074)
SnomedCT 391932009
English Ophthalmodynamometers, Tonometers, Ophthalmic, Tonometers, Ophthalmic Tonometers, Ophthalmotonometers, tonometer, tonometered, tonometers, Tonometer, Ophthalmotonometer (physical object), Ophthalmotonometer
Spanish oftalmotonómetro (objeto físico), oftalmotonómetro

Ontology: Depth of anterior chamber of eye (C0429492)

Concepts Finding (T033)
SnomedCT 251690005, 363948008
English AC - Anterior chamber depth, Anterior chamber depth, depth of anterior chamber of eye (physical finding), anterior chamber depth, depth of anterior chamber of eye, Depth of anterior chamber of eye, of anterior chamber depth, ACD - Anterior chamber depth, Anterior chamber depth (observable entity), Depth of anterior chamber (observable entity), Depth of anterior chamber
Spanish Depth of anterior chamber, Depth of anterior chamber (observable entity), profundidad - cámara anterior, profundidad - cámara anterior (entidad observable), Anterior chamber depth, ACD - Anterior chamber depth, Anterior chamber depth (observable entity), profundidad de la cámara anterior (entidad observable), profundidad de la cámara anterior

Ontology: Applanation tonometry (C0430862)

Concepts Diagnostic Procedure (T060)
SnomedCT 252803002
English AT- Applanation tonometry, applanation tonometry, Applanation tonometry, Applanation tonometry (procedure)
Dutch applanatietonometrie
German Applanationstonometrie
Italian Tonometria da applanazione
Portuguese Tonometria de achatamento
Spanish Tonometría de aplanamiento, tonometría por aplanamiento (procedimiento), tonometría por aplanamiento
Japanese 圧平眼圧測定, アッペイガンアツソクテイ
French Tonométrie d'applanation
Czech Aplanační tonometrie
Hungarian Ellaposítás tonometria

Ontology: Digital tonometry (C0430865)

Concepts Diagnostic Procedure (T060)
SnomedCT 252805009
English Digital tonometry, Digital tonometry (procedure), Portable electronic applanation tonometry
Spanish tonometría digital (procedimiento), tonometría digital

Ontology: Schiotz tonometry (C0848285)

Concepts Diagnostic Procedure (T060)
SnomedCT 389149000
English Schiotz tonometry, Schiotz tonometry (procedure)
Spanish tonometría de Schiotz (procedimiento), tonometría de Schiotz

Ontology: Applanation tonometer (C1271524)

Definition (UMD) Ophthalmic tonometers designed to determine intraocular pressure by measuring the force required to flatten the cornea apex by a fixed amount. These instruments are typically small and reusable instruments and are attached to a slit lamp; the tonometer includes a tip to be applied to the cornea and a manually controlled spring that applies a variable force on the cornea through the tip. The application of the tonometer tip flattens the cornea, producing a thin circular outline that is split into two green semicircles when viewed through the slit lamp oculars; then the force applied is adjusted until both semicircles just overlap and the force value is shown in the instrument scale as pressure (typically in mm Hg). Handheld (electronic penlike devices) and pneumatic applanation tonometers (i.e., pneumatotonomers) are also available. Applanation ophthalmic tonometers (e.g., Goldman and Barraquer types) can measure the amount of force applied; they are intended mainly for assessing ocular hypertension (intraocular pressure between 10 and 24 mm Hg is considered normal), usually to screen patients for glaucoma.
Concepts Medical Device (T074)
SnomedCT 391933004
English Ophthalmic Tonometers, Applanation, Applanation Tonometers, Applanometers, Applanation tonometer (physical object), Applanation tonometer
Spanish tonómetro de aplanamiento (objeto físico), tonómetro de aplanamiento

Ontology: Non-contact tonometry (C1300249)

Concepts Diagnostic Procedure (T060)
SnomedCT 389150000
LNC LP32275-7
English Tonometry.non contact, Air-puff tonometry, Non-contact tonometry (procedure), Non-contact tonometry, Noncontact tonometry
Spanish tonometría sin contacto (procedimiento), tonometría sin contacto

Ontology: Goldmann applanation tonometry (C1300251)

Concepts Diagnostic Procedure (T060)
SnomedCT 389152008
English Goldmann applanation tonometry (procedure), Goldmann applanation tonometry
Spanish tonometría por aplanamiento de Goldmann (procedimiento), tonometría por aplanamiento de Goldmann