Corneal Biomechanics, Optical Properties and Anterior Segment Structural Features in Patients With Pseudoexfoliation (CorPEX)

A Comparative Study of Anterior Segment Structural Features, Biomechanical Behaviour and Optical Properties of the Cornea in Patients With and Without Pseudoexfoliation Syndrome.

The purpose of this study is to assess the effect of pseudoexfoliation syndrome on corneal biomechanics, optical clarity of the cornea, and anterior segment structural features.

Study Overview

• Status: Recruiting
• Conditions: Corneal Densitometry; Pseudoexfoliation Syndrome; Biomechanical Parameters
• Intervention / Treatment: Device: Pentacam-AXL; Device: HD Analyzer; Device: Corvis ST; Device: OCT-A Angiovue; Device: IOLMaster V.5.4; Device: Topcon SP-1P; Other: BCVA (ETDRS), Slit lamp examination, Goldmann Applanation Tonometry, Fundus examination

Detailed Description

A case group of patients with pseudoexfoliation syndrome will ungergo examinations to evaluate corneal optical properties (Pentacam-AXL, HD analyzer), biomechanics (Corvis ST) and anterior segment structural features (OCT-A Angiovue, Pentacam-AXL, IOLMaster V.5.4, Topcon SP-1P). The same examinations will be performed on a group of age-matched controls, and the results will be compared.

Corneal optical density will be assessed by backscatter measurement (COD, corneal optical density) using Pentacam AXL (Oculus, Wetzlar, Germany).

Corneal optical density will also be assessed by forward-scatter measurement (OSI, objective scatter index) using HD Analyzer (Visiometrics, Terassa, Spain, Keeler). The level of agreement between the two optical density indicators (OSI, COD) will be evaluated.

Corneal biomechanics measurements will be performed using Corvis Scheimpflug Technology. The main biomechanical parameter of the Corvis ST is DA (deformation amplitude). DA quantifies how the cornea deforms in response to an air puff and helps evaluate corneal stiffness and elasticity.

An additional objective is the study of structural parameters of the cornea as well as, more broadly, the anterior segment in pseudoexfoliation syndrome (PEX) patients, aiming to understand and describe the effects of PEX with the highest possible accuracy. Specifically, using the Pentacam-AXL (Oculus, Wetzlar, Germany), the IOLMaster V.5.4 (Carl Zeiss Meditec), the OCT-Angiography Angiovue (Optovue, Inc., Fremont, California, USA), and the specular microscope Topcon SP-1P (Topcon Medical Inc., Tokyo, Japan), a comparative study will be conducted across a range of variables and maps: corneal topographic data, keratometric measurements, curvature radius data, pachymetric data, anterior chamber depth and volume, angle width, axial length, pupil diameter, and endothelial cell density. Some of these data, such as central corneal thickness, can be measured by two of the aforementioned devices. In this case, we will also attempt to evaluate the level of agreement between the two devices.

• Study Type: Observational
• Enrollment (Estimated): 86

Contacts and Locations

• Study Contact: Name: Paraskevi Petridou, MD, MSc; Phone Number: 00306985565799; Email: evina_petridou@hotmail.com

Study Locations

• Greece
  • Thessaloniki, Greece, 56429
    • Recruiting
    • 2nd Department of Ophthalmology, Papageorgiou General Hospital
    • Contact: Paraskevi Petridou, MD, MSc; Phone Number: 00306985565799; Email: evina_petridou@hotmail.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Probability Sample

Study Population

Participants will be selected from patients who consult at the outpatient clinic of the 2nd Department of Ophthalmology, General Hospital Papageorgiou, Thessaloniki, Greece.

Description

Inclusion Criteria:

• age 60-80 years.
• unilateral or bilateral pseudophakia (cataract surgery undergone at Papageorgiou General Hospital, Thessaloniki, Greece).
• open anterior chamber angle (grade > 2, van Herick method).

Exclusion Criteria:

• History of intraocular surgery other than uncomplicated cataract surgery (phakoemulsification).
• Cataract surgery within the last 3 months.
• History of ocular trauma.
• Use of contact lenses.
• Corneal pathology.
• Use of anti-VEGF medications.
• History of uveitis or active uveitis.
• Hypertension (IOP > 21 mmHg) or glaucoma.
• Myopia or hyperopia greater than 3 diopters.
• Astigmatism greater than 1.5 diopters.
• Posterior capsular opacification grade 2, 3, or 4 based on the EPCO grading scale.
• Tear break-up time <10 sec

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
PEX group (patients WITH pseudoexfoliation syndrome); right or left eye of pseudophakic patients diagnosted with PEX syndrome pre-operatively (PEX positive, as recorded in the pre-operative medical file)	Device: Pentacam-AXL; Pentacam-AXL (Oculus, Wetzlar, Germany); Device: HD Analyzer; HD Analyzer (Visiometrics, Terassa, Spain, Keeler); Device: Corvis ST; Corvis ST (Oculus, Germany); Device: OCT-A Angiovue; OCT-A Angiovue (Optovue, Inc., Fremont, California, USA); Device: IOLMaster V.5.4; IOLMaster V.5.4 (Carl Zeiss., Meditec); Device: Topcon SP-1P; Topcon SP-1P (Topcon Medical Inc., Tokyo, Japan); Other: BCVA (ETDRS), Slit lamp examination, Goldmann Applanation Tonometry, Fundus examination; BCVA (ETDRS), Slit lamp examination, Goldmann Applanation Tonometry, Fundus Examination
Control group (patients WITHOUT pseudoexfoliation syndrome); right or left eye of pseudophakic patients without a pre-operative diagnosis of pseudoexfoliation syndrome (PEX negative, as recorded in the pre-operative medical file)	Device: Pentacam-AXL; Pentacam-AXL (Oculus, Wetzlar, Germany); Device: HD Analyzer; HD Analyzer (Visiometrics, Terassa, Spain, Keeler); Device: Corvis ST; Corvis ST (Oculus, Germany); Device: OCT-A Angiovue; OCT-A Angiovue (Optovue, Inc., Fremont, California, USA); Device: IOLMaster V.5.4; IOLMaster V.5.4 (Carl Zeiss., Meditec); Device: Topcon SP-1P; Topcon SP-1P (Topcon Medical Inc., Tokyo, Japan); Other: BCVA (ETDRS), Slit lamp examination, Goldmann Applanation Tonometry, Fundus examination; BCVA (ETDRS), Slit lamp examination, Goldmann Applanation Tonometry, Fundus Examination

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Corneal optical density assessed by backscatter measurement	Corneal optical density assessed by backscatter measurement (COD, corneal optical density) using Pentacam AXL (Oculus, Wetzlar, Germany)	Baseline, during examination : approx. 1 hour
Corneal optical density assessed by forward-scatter measurement	Corneal optical density assessed by forward-scatter measurement (OSI, objective scatter index) using HD Analyzer (Visiometrics, Terassa, Spain, Keeler)	Baseline, during examination : approx. 1 hour

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Corneal biomechanics using Corvis Scheimpflug Technology	The main biomechanical parameter of the Corvis ST : DA (deformation amplitude). DA quantifies how the cornea deforms in response to an air puff and helps evaluate corneal stiffness and elasticity.	Baseline, during examination : approx. 1 hour
Optical quality measured by HD-analyzer : Strehl ratio	Specific measurement variable: Total score of Strehl ratio; Value [no dimension];	Baseline, during examination : approx. 1 hour
Optical quality measured by HD-analyzer : MTF cut-off	Specific measurement variable: Total score of Modulation transfer function (MTF) cut-off; Value [c/deg];	Baseline, during examination : approx. 1 hour
Corneal biomechanics using Corvis Scheimpflug Technology : velocity	Velocity during the first and the second applanation of the cornea, measured using Corvis ST [m/s]	Baseline, during examination : approx. 1 hour
Corneal biomechanics using Corvis Scheimpflug Technology : length	First and second applanation length (mm)	Baseline, during examination : approx. 1 hour
Corneal biomechanics using Corvis Scheimpflug Technology : bIOP	Biomechanically corrected IOP (bIOP) (mmHg)	Baseline, during examination : approx. 1 hour

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
The level of agreement between the two optical density indicators (OSI, COD) after standardization	The level of agreement between the two optical density indicators : objective scatter index (OSI), corneal optical density (COD) after standardization. Value [no dimension]	Baseline, during examination : approx. 1 hour
Anterior chamber depth (mm)	Anterior chamber depth (mm)	Baseline, during examination : approx. 1 hour
Endothelial cell density (cells/mm2)	Endothelial cell density (cells/mm2)	Baseline, during examination : approx. 1 hour
Corneal topography (D)	Corneal topography (D)	Baseline, during examination : approx. 1 hour
Anterior chamber volume (mm3)	Anterior chamber volume (mm3)	Baseline, during examination : approx. 1 hour
Anterior chamber angle (°)	Anterior chamber angle (°)	Baseline, during examination : approx. 1 hour
Axial length (mm)	Axial length (mm)	Baseline, during examination : approx. 1 hour
Central corneal thickness (μm)	Central corneal thickness (μm)	Baseline, during examination : approx. 1 hour

Collaborators and Investigators

• Sponsor: Aristotle University Of Thessaloniki
• Collaborators: Papageorgiou General Hospital
• Investigators: Study Chair: Nikolaos Ziakas, Professor, Aristotle University Of Thessaloniki

Study record dates

Study Major Dates

• Study Start (Actual): December 13, 2024
• Primary Completion (Estimated): May 1, 2025
• Study Completion (Estimated): May 1, 2025

Study Registration Dates

• First Submitted: November 19, 2024
• First Submitted That Met QC Criteria: December 9, 2024
• First Posted (Actual): December 12, 2024

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: December 24, 2024
• Last Verified: December 1, 2024

More Information

Terms related to this study

• Keywords: pseudoexfoliation syndrome; biomechanical parameters; corneal transparency
• Additional Relevant MeSH Terms: Pathologic Processes; Disease; Eye Diseases; Uveal Diseases; Iris Diseases; Syndrome; Exfoliation Syndrome
• Other Study ID Numbers: 36661

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Deidentified Individual Participant Data (IPD) that underline published results, along with related data dictionaries, will be available only to researchers who will provide a methodologically sound proposal, after acceptance of the proposed protocol by our Institution's IRB. Data requestors will need to sign a data access agreement. The study protocol and statistical analysis plan will also be available, if needed.
• IPD Sharing Time Frame: Data requests can be submitted starting 9 months after article publication and the data will be made accessible for up to 24 months.
• IPD Sharing Access Criteria: Available only to researchers who will provide a methodologically sound proposal, after acceptance of the proposed protocol by our Institution's IRB. Data requestors will need to sign a data access agreement.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No