Automated iris volume analysis and trabecular meshwork length using anterior segment optical coherence tomography - Application in pseudoexfoliation and pseudoexfoliation glaucoma

Investigation of 3D iris morphology early alteration after implantable collamer lens implantation by using SS-OCT

Purpose

Using a fully automated multitask deep learning method, which enabled simultaneous segmentation and quantification of all major anterior segment structures with swept-source optical coherence tomography (SS-OCT), we aimed to investigate the three-dimensional (3D) alterations in iris morphology before and after implantable collamer lens (ICL) surgery.

Methods

All enrolled patients underwent anterior segment SS-OCT (ANTERION) within one week before and after ICL surgery. A multitask network automatically performed iris SS-OCT image segmentation and quantitative measurements of 3D iris morphology (iris thickness and volume of the inner 1-mm annular area and the outer 1-2-mm annular area, iris curvature [I-Curve], and iris smooth index [SI]).

Results

Forty-six eyes of 27 patients (average age, 26.0 ± 5.3 years) were included in the final data analysis. The spherical equivalent ranged from -15.75 to -4.00 diopters (D). The mean ICL vault values were 537.92 ± 161.69 μm, which positively and significantly correlated with the pre- (r = 0.333, P = 0.024) and postoperative (r = 0.351, P = 0.017) anterior chamber depth (ACD). The mean pupil diameter significantly decreased, whereas both ACD and lens thickness significantly increased postoperatively. The iris thickness, iris volume of the inner 1-mm annular area and the outer 1-2-mm annular area, and SI decreased significantly within one week after ICL implantation. All mean values of the I-Curve increased dramatically postoperatively.

Conclusion

Iris morphology, ACD, and lens thickness were significantly altered after ICL implantation.

The Ocular Surface and the Anterior Segment of the Eye in the Pseudoexfoliation Syndrome: A Comprehensive Review

Pseudoexfoliation syndrome (PXS) is an age-related fibrillopathy where fibrillar exfoliation material accumulates and deposits in ocular and extra-ocular tissue. Within the eye, this substance accumulates on the ocular surface and in the anterior segment of the eye, impacting ocular structures such as the conjunctiva, Tenon's capsule, sclera, cornea, iris, ciliary body, trabecular meshwork, and lens. This review aims to collate the current literature on how each anatomical part of the eye is affected by PXS, with a strong focus on molecular changes. We also summarise the current understanding of the key genetic factors influencing the development of PXS.

Swept Source Optical Coherence Tomography Analysis of a Selected Eye's Anterior Segment Parameters in Patients with Pseudoexfoliation Syndrome

Background: Pseudoexfoliation syndrome (PEX) is a systemic, age-related disorder characterized by the production and accumulation of pseudoexfoliation material. To date, detailed characteristics have not been published regarding the iridocorneal angle and cornea in patients with pseudoexfoliation syndrome determined through swept source optical coherence tomography (SS-OCT). Methods: A total of 150 eyes of patients with pseudoexfoliation syndrome (ages 69–86 years) and 166 eyes in a control group (ages 54–79 years) were analyzed. Results: The central corneal thickness in the PEX group was 549.56 μm and was slightly (insignificantly) higher than that of the control group (540.56 µm). The anterior chamber of the eye was visibly shallower in patients with PEX syndrome than in those of the control group (2.49 mm vs. 3.07 mm; p < 0.001). The Fourier analysis parameters of the cornea showed multiple differences between the PEX and control groups. With respect to iris area, the parameters showed statistically significant differences between the PEX and control groups in all four quadrants of the eye. No statistical significance was found in the PEX group for the iridocorneal angle parameters, or corneal and lens parameters depending on gender and age. Conclusions: PEX syndrome is characterized by a significant impact on the anterior eye segment, including higher anterior and posterior keratometric values, lower anterior chamber depth, higher iris thickness, and narrower angle parameters. The characteristic anterior eye segment features of PEX syndrome can be detected using SS-OCT, which could potentially assist clinicians in properly managing the disease.