Automated Applanation Tonometry - Updated

NCT ID: NCT07298356

Last Updated: 2025-12-23

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

NOT_YET_RECRUITING

Clinical Phase

NA

Total Enrollment

200 participants

Study Classification

INTERVENTIONAL

Study Start Date

2025-12-29

Study Completion Date

2026-12-29

Brief Summary

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Goldmann Applanation Tonometry (GAT) is considered the clinical gold standard for eye pressure measurements and yet it is known to be a subjective measurement with limited repeatability and limited portability. Another clinical standard for checking eye pressure is known as the pneumotonometer. This method is more objective but not portable. The purpose of this study is to develop new methods of measuring eye pressure that are more objective, reproducible and portable. In this study, we will be comparing the eye pressure measurements using 2 investigational methods to GAT and pneuumotonometer.

Detailed Description

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This is a prospective study. Patients presenting for their scheduled eye appointments will be recruited by verbal communication. Following informed consent, intraocular pressure (IOP) measurements will be made by the following methods:

Standard Goldmann Applanation Tonometry (GAT): this is the standard method for IOP measurement in clinical practice. The eye is given topical fluorescein/anesthetic, the GAT prism contacts the eye while the observer looks through the slit lamp machine ocular using blue light illumination to visual the applanation mires. The GAT dial is adjusted until mire alignment is achieved and the IOP measurement is read off the GAT dial.

Pneumotonometer: This is what is done in routine eye care. You will receive a topical anesthetic (numbing agent). A probe will touch the front of the eye while the machine measures the eye pressure.

Fixed force GAT: From the patient perspective, this method will feel identical to the standard GAT. The eye is given topical fluorescein/anesthetic. The GAT dial is set at 1.8 or 2.0, a complementary metal oxide semiconductor (C-MOS) camera is connected to one of the oculars of the slit lamp machine and under blue light illumination, the GAT prism contacts the eye while the CMOS camera makes a video of the mire appearance through the ocular. The diameters of the recorded mire images are measured and the IOP is calculated based on the mire diameter. A similar method using an iPod touch camera has been previously published by this PI.

Upright applanating prototype: With this prototype, an applanating prism (custom manufactured with medical grade acrylic in an ISO-13485 certified facility) is attached to a fixed-force spring that creates a force equivalent to 1.8 or 2.0 on the GAT dial. Blue LED lights on the prototype are used to create the blue illumination similar to the blue light used in clinical practice on the slit lamp or Perkins tonometer. A C-MOS camera is aligned with the GAT prism to image the applanation mires. The eye is given topical fluorescein/anesthetic. Like fixed-force GAT, the GAT prism contacts the eye while the CMOS camera makes a video of the mire appearance. The diameters of the recorded mire images are measured and the IOP is calculated based on the mire diameter.

The order of the above 4 measurements will be randomized.

Conditions

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Glaucoma Glaucoma, Suspect

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

In this 2 investigational methods (Fixed-force GAT and handheld tonometer) will be compared to the 2 standard methods (Standard GAT and pneumotonometer).
Primary Study Purpose

DIAGNOSTIC

Blinding Strategy

NONE

Study Groups

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Standard GAT

This is the gold-standard method for IOP measurement in clinical practice

Group Type ACTIVE_COMPARATOR

Standard GAT

Intervention Type DEVICE

Standard Goldmann Applanation Tonometry (GAT): this is the standard method for IOP measurement in clinical practice

Fixed-force GAT

From the patient perspective, this method will feel identical to the standard GAT. The eye is given topical fluorescein/anesthetic. The GAT dial is set at 1.8 or 2.0, a C-MOS camera is connected to one of the oculars of the slit lamp machine and under blue light illumination, the GAT prism contacts the eye while the CMOS camera makes a video of the mire appearance through the ocular. The diameters of the recorded mire images are measured and the IOP is calculated based on the mire diameter

Group Type EXPERIMENTAL

Fixed force GAT

Intervention Type DEVICE

An investigational device similar to standard GAT

Upright applanating prototype

With this prototype, an applanating prism (custom manufactured with medical grade acrylic in an ISO-13485 certified facility) is attached to a fixed-force spring that creates a force equivalent to 1.8 or 2.0 on the GAT dial. Blue LED lights on the prototype are used to create the blue illumination similar to the blue light used in clinical practice on the slit lamp or Perkins tonometer. A C-MOS camera is aligned with the GAT prism to image the applanation mires. The eye is given topical fluorescein/anesthetic. Like fixed-force GAT, the GAT prism contacts the eye while the CMOS camera makes a video of the mire appearance. The diameters of the recorded mire images are measured and the IOP is calculated based on the mire diameter

Group Type EXPERIMENTAL

Upright applanating prototype

Intervention Type DEVICE

An investigational device, prism used in standard and fixed-force GAT is attached to a portable device

Pneumotonometer

This is another standard method for IOP measurement in clinical practice

Group Type ACTIVE_COMPARATOR

Pneumotonometer

Intervention Type DEVICE

This is a standard for checking eye pressure. A topical anesthetic (numbing agent). A probe will touch the front of the eye while the machine measures the eye pressure

Interventions

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Standard GAT

Standard Goldmann Applanation Tonometry (GAT): this is the standard method for IOP measurement in clinical practice

Intervention Type DEVICE

Fixed force GAT

An investigational device similar to standard GAT

Intervention Type DEVICE

Upright applanating prototype

An investigational device, prism used in standard and fixed-force GAT is attached to a portable device

Intervention Type DEVICE

Pneumotonometer

This is a standard for checking eye pressure. A topical anesthetic (numbing agent). A probe will touch the front of the eye while the machine measures the eye pressure

Intervention Type DEVICE

Eligibility Criteria

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Inclusion Criteria

* Presenting for a routine eye exam
* ≥ 18 years of age
* Able and willing to give consent

Exclusion Criteria

* History of corneal scarring
* Active infection of the eye
* Ocular surface trauma or infection
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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Duke University

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Joanne Wen, MD

Role: PRINCIPAL_INVESTIGATOR

Duke Eye Center

Locations

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Duke Eye Center

Durham, North Carolina, United States

Site Status

Countries

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United States

Central Contacts

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Sarah Jones

Role: CONTACT

Phone: 919 681 6584

Email: [email protected]

Facility Contacts

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Joanne Wen, MD

Role: primary

Other Identifiers

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Pro00106111_1

Identifier Type: -

Identifier Source: org_study_id