The Effect of Compliance With Preoperative Posturing Advice and Head Movements on the Progression of Macula-On Retinal Detachment

Abstract

Purpose: The aim of this study was to explore the relationship between compliance with preoperative posturing advice and progression of macula-on retinal detachment (RD) and to evaluate whether head positioning or head motility contributes most to RD progression.

Methods: Sixteen patients with macula-on RD were enrolled, admitted to the ward, and instructed to posture preoperatively. The primary outcome parameter was compliance, which was defined as the average head orientation deviation from advised positioning. Secondary outcome parameters included the average rotational and linear head acceleration. The head orientation and acceleration were measured with a head-mounted inertial measurement unit (IMU). Optical coherence tomography (OCT) imaging was performed at baseline and during natural interruptions of posturing for meals and toilet visits to measure RD progression toward the fovea.

Results: The Spearman correlation coefficient with RD progression was 0.37 (P = 0.001, r _s ² = 0.13) for compliance, 0.52 (P < 0.001, r _s ² = 0.27) for rotational acceleration, and 0.49 (P < 0.001, r _s ² = 0.24) for linear acceleration. The correlation coefficient between RD progression and rotational acceleration was statistically significantly higher than the correlation coefficient between RD progression and compliance (P = 0.034).

Conclusion: The strength of the correlation between RD progression and compliance was moderate. However, the correlation between RD progression and rotational and linear acceleration was much stronger. Preoperative posturing is effective by reducing head movements rather than enforcing head positioning.

Translational relevance: Monitoring the efficacy of preoperative posturing in macula-on RD using OCT and IMU measurements shows that a new and combined application of these technologies leads to clinically relevant insights.

Keywords: compliance; head motility; preoperative posturing; progression; retinal detachment.

Figure 1

Schematic drawing of the position of the unit Z-vector (blue arrow) and gravity vector (red arrow) within the IMU coordinate system. When the patient is positioned supine with the IMU fixed on the forehead, the world Z-axis is aligned with the IMU Z′-axis (situation A). The coordinates of the unit Z-vector (blue arrow) on the IMU X′-, Y′- and Z′-axis will be 0, 0, and 1, respectively, in situation A. In situation B, a 30° rotation (θ) around the world X-axis has resulted in a 30° tilt of the IMU Y′- and Z′-axis and in a change of the coordinates of the unit Z-vector on the Y′-axis (this will be sin[θ]) and Z′-axis (cos [θ]). Rotation around the world Z-axis in either situation A or B will not change the coordinates of the unit Z-vector.

Figure 2

The optimal direction of gravity was defined as perpendicular to the detached retina closest to the fovea (red arrow).

Figure 3

Example of the course of progression and the IMU parameters of a 56-year-old patient. The patient had an RD in the superior temporal quadrant of the right eye and supine posturing. During the day, most intervals showed progression, while during the night, regression of 2591 μm was seen (A). The orientation deviation was lower during posturing intervals than during interruptions, especially during the night (B, interval 5).

Figure 4

Scatter plots of the four IMU parameters with RD progression. RD progression was defined as the average RD border displacement velocity (μm/h) and calculated for posturing intervals (circles) and interruptions (triangles) separately. The scatter plots display the nonlinear and negative relationship between the four IMU parameters and RD progression. The strength of the Spearman correlation (R_s) was moderate for the relationship between RD progression and average orientation deviation from advised positioning (A) and optimal positioning (B). The strength of the correlation between RD progression and rotational acceleration (C) and linear acceleration (D) was much stronger.