Estimation of angle kappa and pupil barycentre configuration in myopic tilted disc syndrome

Abstract

Background To evaluate the angle kappa and pupil barycentre configuration in patients with myopic tilted disc syndrome (TDS). Methods Thirty‐five eyes of 35 patients with TDS were included in the study. Thirty‐five eyes of 35 age‐ and sex‐matched healthy subjects were enrolled in the control group. All measurements were performed with the Lenstar LS 900. Angle kappa was calculated according to Pythagorean theorem using the x and y co‐ordinates of the pupil centre. Pupil dx and pupil dy values (pupil dx: x co‐ordinate of pupil centre relative to corneal apex, pupil dy: y co‐ordinate of pupil centre relative to corneal apex) were used to evaluate the pupil barycentre configuration. Central corneal thickness, white to white (cornea diameter), pupil diameter, anterior chamber depth, lens thickness, and axial length were also measured. Results The calculated mean angle kappa distance was 0.27 ± 0.15 mm in the TDS group and 0.29 ± 0.23 mm in the control group (p = 0.42). The mean pupil dx was −0.01 ± 0.24 mm in the TDS group and −0.17 ± 0.14 mm in the control group (p = 0.006). The mean pupil dy was −0.02 ± 0.13 mm in the TDS group and −0.05 ± 0.22 mm in the control group (p = 0.65). Conclusions The pupil barycentre in TDS cases was statistically significantly closer to the corneal vertex on the horizontal plane compared to the control group. However, there was no statistically significant differences in terms of angle kappa and pupil dy values between the groups. According to our results, refractive surgery can be performed safely with respect to complications related to decentration of ablation zone and decentration of multifocal intraocular lenses in these groups of patients.

Oncoimmunology Meets Organs-on-Chip

“…As delineated by the two formula D and E in Figure 5, y and x represent the projections of the step lengths on Y and X axes, respectively. The two catheti y, x and the hypotenuse s constitute a right-angled triangle (Figure 5), where the angular variation α a is easily computable by the inverse tangent formula C in Figure 5 (Dummer et al, 2016;Lin, 2019;Cankaya et al, 2020;Zhang et al, 2020). Of note, each step length s of the immune cell track is indissolubly linked to its relative α value conventionally referred to the X axis, as evidenced in Figure 5.…”

Pupil barycenter configuration in patients with myopia and hyperopia

“…In refractive surgery, the kappa angle is a clinically important entity and may play a role in refractive results [6,7]. A wide kappa angle (0.6 mm) may cause misalignment errors during photoablation in laser refractive surgery and lens decentralization after multifocal lens implantation, leading to irregular astigmatism, photic phenomena (glare and halo), and decreased best-corrected visual acuity [8].…”

“…Although different methods are used to measure the kappa angle, the corneal re ection method, using a synoptophore or major amblyoscope, is used to measure the true kappa angle [8]. Orbscan II (Bausch & Lomb, Rochester, NY, USA), Galilei (Ziemer Ophthalmic Systems, Port, Switzerland), and OPD Scan II (Nidek, Gamagori, Japan) are the newer devices used to determine the kappa angle [9].…”

“…Lenstar does not directly determine the kappa angle. Instead, it measures the pupil barycenter [3] by measuring the distance (x and y Cartesian values) between the corneal vertex and the pupillary center, from which the kappa angle can be determined according to the Pythagorean theorem [8].…”

Comparison of Preoperative Angle Kappa Measurements in the Eyes of Cataract Patients Obtained from Pentacam Scheimpflug System, Optical Low-Coherence Reflectometry, and Ray-Tracing Aberrometry

“…Pentacam has been more and more popular in measuring angle kappa for the past few years [7]. In addition, some reports have shown that Lenstar and iTrace were also commonly used to estimate angle kappa [8,9]. However, no published data has reported a comparison in the angle kappa among three devices.…”