Loading…

Protocol - Intraocular Pressure

Add to My Toolkit
Description:

Intraocular pressure (IOP) is measured using the TONO-PEN® XL instrument. The cornea is prepared by introducing one drop of anesthetic onto the surface of the eye and the TONO-PEN® is used to obtain four valid IOP measurements. The instrument calculates an average and the examiner records the average. The instrument also provides the reliability level of the measurement. Only those readings that have a 5% variability level are recorded as they are considered to be accurate.

Protocol:

Measuring Intraocular Pressure Using the TONO-PEN® XL.

Patient Preparation

The Ocu-Film located on the tip of the TONO-PEN® XL contains natural rubber LATEX which may cause allergic reactions. Question patients about allergies to Latex before examining them with the TONO-PEN® XL.

To prepare a patient for an IOP measurement:

1. Instill a drop of topical anesthetic onto the eye to be examined.

2. Position the patient, seated or supine, in front of a fixation target; or have the patient fixate on a point of reference (i.e. ear, nose, distant object) to minimize eye movement.

Note: The TONO-PEN® XL will function in any stable position.

Patient Examination

To Perform an IOP measurement:

1. Instruct the patient to look straight ahead at the fixation target with his/her eyes fully open.

2. Hold the TONO-PEN® XL unit as you would a pencil.

3. Position yourself to facilitate viewing of the probe tip and patient's cornea where contact will be made. For normal corneas, central corneal contact is recommended.

4. Brace the heel of your hand on the patient's cheek for stability while holding the TONO-PEN® XL unit perpendicular to and within ½ inch of the patient's cornea.

5. To initiate an IOP measurement, depress the Operator's Button once, and only once.

  • Initially you will see a brief display of 18.8.8.81. This is a self-test of the LCD (Liquid Crystal Display). If any of the LCD segments are not displayed, the TONO-PEN® requires service.
  • If a momentary display of ICALI is seen, followed immediately by a single row of dashes [- - - ], it indicated that the TONO-PEN® requires calibration before it will measure.
  • If a double row of dashes is seen and a "beep" tone is heard, it indicates that the TONO-PEN® is ready to measure IOP. Proceed with applanation within 15 seconds.

6. Once active, after [ ==== ] is displayed and a "beep" tone is heard, touch the TONO-PEN® XL unit to the cornea lightly and briefly, then withdraw. Repeat several times. The corneal surface needs only to be momentarily contacted: indentation is not required and may lead to inaccurate readings.

TONO-PEN® XL
TONO-PEN® XL
Thumbnail: Click to open

7. A chirp will sound and a digital IOP measurement will be displayed each time a valid reading is obtained. The single horizontal bar at the bottom of the LCD, indicating statistical reliability, will not be displayed with each single IOP measurement.

8. After four (4) valid readings are obtained, a final beep will sound and the averaged measurement will appear on the LCD along with single bar denoting statistical reliability.

9. To take another measurement, reactivate the TONO-PEN® XL unit by pressing and releasing the activation switch as described in step 5.

10. Replace the Ocu-Film Tip Cover before using the TONO-PEN® XL unit on another patient and before storage.

Criteria for Emergency Referral

Any participant with intraocular pressure greater than 40 mm Hg should be referred immediately to a medical center. Notify the medical center by phone that the participant is on the way and that the patient has a high intraocular pressure and may need a laser iridotomy.

Criteria for Non-emergent Referral

Any participant with intraocular pressures between 21 mm Hg and 40 mm Hg or a potentially occludable angle should be referred to an ophthalmologist for a glaucoma-suspect work-up. The participant will be educated as to the seriousness of further testing and follow-up.

Protocol Name from Source:

The Expert Review Panel has not reviewed this measure yet.

Availability:

Publicly available

Personnel and Training Required

Trained ophthalmic technicians or ophthalmologists

Equipment Needs

TONO-PEN® XL Applanation Tonometer (Reichert Ophthalmic Instruments, Depew, NY)

TONO-PEN® is a registered trademark Reichert, Inc.

Note: This protocol uses TONO-PEN® to measure intraocular pressure. This instrument has the advantages of portability and is relatively easy to use. Other hand-held instruments can be used to measure intraocular pressure. If other instruments are used, the reproducibility of the measurements should be comparable to those acquired with this protocol. In addition, when other instruments are used to collect these measurements, the manufacturer and model of equipment should be recorded. These other devices may require some different steps than are described in this protocol. Investigators should follow the equipment manufacturer's instructions to ensure quality control.

Requirements
Requirement CategoryRequired
Major equipment Yes
Specialized training Yes
Specialized requirements for biospecimen collection No
Average time of greater than 15 minutes in an unaffected individual No
Mode of Administration

Clinical Measurement

Life Stage:

Child, Adolescent, Adult

Participants:

Adults aged ≥ 40 years*

*While this protocol was used in a study of adults aged ≥ 40 years, the Ocular Working Group suggests that the same methodology can be used for individuals below age 40 and for children who are old enough to be able to tolerate the exam (usually by age 5). The WG notes that this methodology can also be used in children younger than 5 years, but that general anesthesia may be necessary.

Specific Instructions:

This protocol uses TONO-PEN® to measure intraocular pressure. This instrument has the advantages of portability and is relatively easy to use. Other hand-held instruments can be used to measure intraocular pressure. If other instruments are used, the reproducibility of the measurements should be comparable to those acquired with this protocol. In addition, when other instruments are used to collect these measurements, the manufacturer and model of equipment should be recorded. These other devices may require some different steps than are described in this protocol. Investigators should follow the equipment manufacturer's instructions to ensure quality control.

Selection Rationale

The TONO-PEN® is an easy to use, portable hand-held electronic, digital pen-like instrument that determines IOP by making contact with the cornea, after use of topical anesthetic eye drops. This is especially useful for very young children and patients unable to reach a slit lamp due to disability. Measurement of intraocular pressure using this instrument does not require an office setting. It provides readings that correlate closely with Goldmann Tonometry, which was considered by the PhenX Working Group but was deemed to be of too high of burden for use by investigators who are not ocular experts.

Language

English

Standards
StandardNameIDSource
Common Data Elements (CDE) Eye Tonometer Intraocular Pressure Number 3008671 CDE Browser
Logical Observation Identifiers Names and Codes (LOINC) Intraocular pressure proto 62691-1 LOINC
Derived Variables

None

Process and Review

The Expert Review Panel has not reviewed this measure yet.

Source
University of Southern California, The Los Angeles Latino Eye Study (LALES). 2000-2003.
General References

Varma R, Paz SH, Azen SP, Klein R, Globe D, Torres M, Shufelt C, Preston-Martin S; Los Angeles Latino Eye Study Group. (2004). The Los Angeles Latino Eye Study: design, methods, and baseline data. Ophthalmology, 111(6):1121-31.

Protocol ID:

110701

Variables:
Export Variables
Variable NameVariable IDVariable DescriptionVersiondbGaP Mapping
PX110701_Intraocular_Pressure_Tono-Pen_Model PX110701010000 Intraocular Pressure Tono-Pen Model 4 N/A
PX110701_Left_Eye_Intraocular_Pressure_1 PX110701040100 Left Eye Intraocular Pressure measured, first measurement 4 N/A
PX110701_Left_Eye_Intraocular_Pressure_2 PX110701040200 Left Eye Intraocular Pressure measured, second measurement 4 N/A
PX110701_Left_Eye_Intraocular_Pressure_3 PX110701040300 Left Eye Intraocular Pressure measured, third measurement 4 N/A
PX110701_Left_Eye_Intraocular_Pressure_4 PX110701040400 Left Eye Intraocular Pressure measured, fourth measurement 4 N/A
PX110701_Left_Eye_Statistical_Reliability_Level1 PX110701050100 Left Eye Statistical Reliability Level measured, first measurement 4 N/A
PX110701_Left_Eye_Statistical_Reliability_Level2 PX110701050200 Left Eye Statistical Reliability Level measured, second measurement 4 N/A
PX110701_Left_Eye_Statistical_Reliability_Level3 PX110701050300 Left Eye Statistical Reliability Level measured, third measurement 4 N/A
PX110701_Left_Eye_Statistical_Reliability_Level4 PX110701050400 Left Eye Statistical Reliability Level measured, fourth measurement 4 N/A
PX110701_Right_Eye_Intraocular_Pressure_1 PX110701020100 Right Eye Intraocular Pressure measured, first measurement 4 N/A
PX110701_Right_Eye_Intraocular_Pressure_2 PX110701020200 Right Eye Intraocular Pressure measured, second measurement 4 N/A
PX110701_Right_Eye_Intraocular_Pressure_3 PX110701020300 Right Eye Intraocular Pressure measured, third measurement 4 N/A
PX110701_Right_Eye_Intraocular_Pressure_4 PX110701020400 Right Eye Intraocular Pressure measured, fourth measurement 4 N/A
PX110701_Right_Eye_Statistical_Reliability_Level1 PX110701030100 Right Eye Statistical Reliability Level measured, first measurement 4 N/A
PX110701_Right_Eye_Statistical_Reliability_Level2 PX110701030200 Right Eye Statistical Reliability Level measured, second measurement 4 N/A
PX110701_Right_Eye_Statistical_Reliability_Level3 PX110701030300 Right Eye Statistical Reliability Level measured, third measurement 4 N/A
PX110701_Right_Eye_Statistical_Reliability_Level4 PX110701030400 Right Eye Statistical Reliability Level measured, fourth measurement 4 N/A
Research Domain Information
Measure Name:

Intraocular Pressure

Release Date:

February 26, 2010

Definition

Procedure for the measurement of intraocular pressure (IOP) using the TONO-PEN® XL Applanation Tonometer.

TONO-PEN® is a registered trademark Reichert, Inc.

Purpose

This procedure is used to measure intraocular pressure (IOP). An elevated IOP can be dangerous because people with varying degrees of IOP elevation may develop damage to the optic nerve.

Keywords

Ocular, Eye, Intraocular pressure, IOP, Los Angeles Latino Eye Study, LALES