Non-Funduscopic Slit Lamp Assessment of the Posterior Hyaloid Membrane - A Simpler and More Effective Way of Clinically Diagnosing Posterior Vitreous Detachments.

Abstract

Purpose: To assess the clinical utility of a simpler method of detecting a complete posterior vitreous detachment (PVD) - visualization of the posterior hyaloid membrane at the slit lamp - which does not require expert dilated fundus examination skills, special instrumentation (fundoscopy lenses), or imaging devices (OCT or B-scan).

Design: Cross-sectional case series PARTICIPANTS: All eligible patients presenting to the retina clinic during the study period were consecutively examined.

Methods: All patients were examined for the presence or absence of a PVD using the posterior hyaloid membrane assessment method, Weiss ring assessment method, and via optical coherence tomography (OCT) performed by three masked graders.

Main outcome measures: The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), receiver operator curves (ROC) and areas under the curve (AUC) were analyzed to assess the clinical utility of the two methods.

Results: A total of 206 eyes of 118 patients were included. The incidence of true posterior vitreous detachments based on OCT was 57.3%. The posterior hyaloid assessment method was more sensitive than the Weiss ring assessment method (89.8% vs 79.7%, p-value: 0.04), and had a higher NPV (87.5% vs 78.2%, p-value: <0.01). There was no significant difference in specificity between the posterior hyaloid membrane and Weiss ring methods (95.5% vs 97.4%, p-value: 0.5) or PPV (96.4% vs 97.3%, p-value: 0.2). The AUC for the posterior hyaloid assessment and Weiss Ring methods were 0.93 and 0.89, respectively (chi-squared=2.84, p-value: 0.09).

Conclusions: This study shows that this method of assessing the posterior hyaloid status is clinically meaningful and has a high sensitivity, specificity, positive predictive value, negative predictive value, and area under the curve. Compared to the Weiss ring method, the posterior hyaloid membrane assessment has a significantly higher sensitivity and negative predictive value and a similarly high specificity, positive predictive value, and area under the curve. Although trainees are not regularly taught this diagnostic skill, these results support that visualizing and assessing the posterior hyaloid membrane should be in every ophthalmologist's diagnostic skill repertoire.