GlaucomaNCT05235321
Automated Applanation Tonometry
A study testing Standard GAT, Fixed force GAT and Upright applanating prototype in people with Glaucoma and Glaucoma, Suspect, run by Duke University at 1 site in United States.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Glaucoma, Glaucoma, Suspect
- What is being tested?
- Standard GAT, Fixed force GAT and Upright applanating prototype
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 118 participants
- Where
- 1 siteUnited States
- Study dates
- 21 Nov 2022to 31 May 2024
- Phase
- Interventional
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Presenting for a routine eye exam
- ≥ 18 years of age
- Able and willing to give consent
Who cannot join
- History of corneal scarring
- Active infection of the eye
Trial locations and contacts
1 site in 1 country.
About this study
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. The purpose of this study is to develop an automated and objective method for performing applanation tonometry using standard ophthalmic equipment as well as using 2 portable prototypes.
Read the detailed description
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 3 upright methods and 1 supine measurements:
- 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.
- 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 3 measurements will be randomized. The 4th measurement will be made with the patient in the supine position. Here, the subject will be reclined in our standard clinical exam chair until the iris plane is parallel to the ground.
- Supine applanating prototype: With this method, a 5 gram clear acrylic cylinder (custom manufactured with medical grade acrylic in an ISO-13485 certified facility) is aligned with the lens of the CMOS camera and the distal tip of the cylinder is illuminated with blue light using an LED similar to the blue light used in clinical practice on the slit lamp or Perkins tonometer. The eye is given topical fluorescein/anesthetic. While the CMOS camera is recording, the 5 gram weight will rest upon the eye and circular applanation mires are recorded. The diameters of the recorded mire images are measured and the IOP is calculated based on the mire diameter. A similar method using an iPhone 6 camera has been previously published by this PI. The clear cylinder in this study is the same as that used in this prior study.
- Conditions
- Glaucoma, Glaucoma, Suspect
- Being tested
- Standard GAT, Fixed force GAT, Upright applanating prototype, Supine Applanating Prototype
- Medical subject headings
- Glaucoma, Ocular Hypertension
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Standard GATDevice
Standard Goldmann Applanation Tonometry (GAT): this is the standard method for IOP measurement in clinical practice
Fixed force GATDevice
An investigational device similar to standard GAT
Upright applanating prototypeDevice
An investigational device, prism used in standard and fixed-force GAT is attached to a portable device
Supine Applanating PrototypeDevice
An investigational device, prism used in standard and fixed-force GAT is attached to a portable device performed in the supine position
| Study group | Role | What they receive |
|---|---|---|
| Standard GAT | Active comparator | This is the standard method for IOP measurement in clinical practice Receives: Device: Standard GAT |
| Fixed-force GAT | Experimental | 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 Receives: Device: Fixed force GAT |
| Upright applanating prototype | Experimental | 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 Receives: Device: Upright applanating prototype |
| Supine Applanating Prototype | Experimental | With this method, a 5 gram clear acrylic cylinder (custom manufactured with medical grade acrylic in an ISO-13485 certified facility) is aligned with the lens of the CMOS camera and the distal tip of the cylinder is illuminated with blue light using an LED similar to the blue light used in clinical practice on the slit lamp or Perkins tonometer. The eye is given topical fluorescein/anesthetic. While the CMOS camera is recording, the 5 gram weight will rest upon the eye and circular applanation mires are recorded. The diameters of the recorded mire images are measured and the IOP is calculated based on the mire diameter Receives: Device: Supine Applanating Prototype |
What is being measured
The primary outcome is the main question the study is designed to answer.
Intraocular Pressure (IOP)
Intraocular pressure (IOP) as measured by Standard GAT, Fixed-force GAT, and Upright Applanating Prototype.
Measured: Single study visit, approximately 20 minutes
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Feb 2022
- Study start21 Nov 2022
- Primary completion31 May 2024
- Study completion31 May 2024
Why it stopped: device updates needed
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for GlaucomaStudies of the same condition, open and under way.
- More trials run by Duke UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Diagnosis
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- In this study, 3 eye pressure measurements will be made in the upright position (standard GAT, fixed force GAT, upright applanating prototype) and 1 in the supine position (supine applanating prototype).
- Masking
- None (open label)
- Enrolment
- 118 participants (actual)
Sponsor and investigators
- Lead sponsor
- Duke University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Joanne Wen, MD, Principal investigator, Duke Eye Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05235321
- Sponsor's protocol ID
- Pro00106111
- Status last verified
- Aug 2026
- First submitted
- 2 Feb 2022
- Last updated
- 11 Sep 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- No: No Currently, there is no plan to share data with other researchers.
Study at a glance
From the registry record, last updated by the sponsor on 11 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Automated Applanation Tonometry
- ClinicalTrials.gov ID
- NCT05235321
- Acronym / sponsor ID
- Pro00106111
- Conditions
- Glaucoma, Glaucoma, Suspect
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: device updates needed
- Enrolment
- 118 participants (actual)
- Lead sponsor
- Duke UniversityUniversity, hospital or other
- Study start
- 21 Nov 2022 (actual)
- Primary completion
- 31 May 2024 (actual)
- Study completion
- 31 May 2024 (actual)
- First posted
- 11 Feb 2022 (actual)
- Results
- Posted 11 Sep 2026
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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. The purpose of this study is to develop an automated and objective method for performing applanation tonometry using standard ophthalmic equipment as well as using 2 portable prototypes.
Detailed description
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 3 upright methods and 1 supine measurements:
- 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.
- 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 3 measurements will be randomized. The 4th measurement will be made with the patient in the supine position. Here, the subject will be reclined in our standard clinical exam chair until the iris plane is parallel to the ground.
- Supine applanating prototype: With this method, a 5 gram clear acrylic cylinder (custom manufactured with medical grade acrylic in an ISO-13485 certified facility) is aligned with the lens of the CMOS camera and the distal tip of the cylinder is illuminated with blue light using an LED similar to the blue light used in clinical practice on the slit lamp or Perkins tonometer. The eye is given topical fluorescein/anesthetic. While the CMOS camera is recording, the 5 gram weight will rest upon the eye and circular applanation mires are recorded. The diameters of the recorded mire images are measured and the IOP is calculated based on the mire diameter. A similar method using an iPhone 6 camera has been previously published by this PI. The clear cylinder in this study is the same as that used in this prior study.
Study design
- Primary purpose
- Diagnosis
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 4
- Model description
- In this study, 3 eye pressure measurements will be made in the upright position (standard GAT, fixed force GAT, upright applanating prototype) and 1 in the supine position (supine applanating prototype).
| Arm | Type | Receives |
|---|---|---|
| Standard GAT | Active comparator | Device: Standard GATThis is the standard method for IOP measurement in clinical practice |
| Fixed-force GAT | Experimental | Device: Fixed force GATFrom 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 |
| Upright applanating prototype | Experimental | Device: Upright applanating prototypeWith 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 |
| Supine Applanating Prototype | Experimental | Device: Supine Applanating PrototypeWith this method, a 5 gram clear acrylic cylinder (custom manufactured with medical grade acrylic in an ISO-13485 certified facility) is aligned with the lens of the CMOS camera and the distal tip of the cylinder is illuminated with blue light using an LED similar to the blue light used in clinical practice on the slit lamp or Perkins tonometer. The eye is given topical fluorescein/anesthetic. While the CMOS camera is recording, the 5 gram weight will rest upon the eye and circular applanation mires are recorded. The diameters of the recorded mire images are measured and the IOP is calculated based on the mire diameter |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Presenting for a routine eye exam
- ≥ 18 years of age
- Able and willing to give consent
Key exclusion criteria (2 listed)
- History of corneal scarring
- Active infection of the eye
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Standard GATStandard Goldmann Applanation Tonometry (GAT): this is the standard method for IOP measurement in clinical practice | Device | Standard GAT |
| Fixed force GATAn investigational device similar to standard GAT | Device | Fixed-force GAT |
| Upright applanating prototypeAn investigational device, prism used in standard and fixed-force GAT is attached to a portable device | Device | Upright applanating prototype |
| Supine Applanating PrototypeAn investigational device, prism used in standard and fixed-force GAT is attached to a portable device performed in the supine position | Device | Supine Applanating Prototype |
Primary outcome
Intraocular Pressure (IOP)
Time frame: Single study visit, approximately 20 minutes
Intraocular pressure (IOP) as measured by Standard GAT, Fixed-force GAT, and Upright Applanating Prototype.
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 11 Sep 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Individual participant dataSharing planned: No. No Currently, there is no plan to share data with other researchers.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Joanne Wen, MD principal investigator
Duke Eye Center
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Standard GAT, Fixed force GAT and Upright applanating prototype in people with Glaucoma and Glaucoma, Suspect, run by Duke University at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: stopped early, as of the sponsor's last update on 11 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Yes. Results are posted in the registry (first posted 11 Sep 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Intraocular Pressure (IOP) (time frame: Single study visit, approximately 20 minutes). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 11 Sep 2026.