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.
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
86
Pentacam-AXL (Oculus, Wetzlar, Germany)
HD Analyzer (Visiometrics, Terassa, Spain, Keeler)
Corvis ST (Oculus, Germany)
2nd Department of Ophthalmology, Papageorgiou General Hospital
Thessaloniki, Greece
RECRUITINGCorneal optical density assessed by backscatter measurement
Corneal optical density assessed by backscatter measurement (COD, corneal optical density) using Pentacam AXL (Oculus, Wetzlar, Germany)
Time frame: 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)
Time frame: Baseline, during examination : approx. 1 hour
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.
Time frame: Baseline, during examination : approx. 1 hour
Optical quality measured by HD-analyzer : Strehl ratio
Specific measurement variable: Total score of Strehl ratio; Value \[no dimension\];
Time frame: 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 \[c/deg\];
Time frame: 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 \[m/s\]
Time frame: Baseline, during examination : approx. 1 hour
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OCT-A Angiovue (Optovue, Inc., Fremont, California, USA)
IOLMaster V.5.4 (Carl Zeiss., Meditec)
Topcon SP-1P (Topcon Medical Inc., Tokyo, Japan)
BCVA (ETDRS), Slit lamp examination, Goldmann Applanation Tonometry, Fundus Examination
Corneal biomechanics using Corvis Scheimpflug Technology : length
First and second applanation length (mm)
Time frame: Baseline, during examination : approx. 1 hour
Corneal biomechanics using Corvis Scheimpflug Technology : bIOP
Biomechanically corrected IOP (bIOP) (mmHg)
Time frame: Baseline, during examination : approx. 1 hour