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

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.

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