The design and validation of an optical coherence tomography-based classification system for focal vitreomacular traction

Abstract

Purpose: To develop and validate a classification system for focal vitreomacular traction (VMT) with and without macular hole based on spectral domain optical coherence tomography (SD-OCT), intended to aid in decision-making and prognostication.

Methods: A panel of retinal specialists convened to develop this system. A literature review followed by discussion on a wide range of cases formed the basis for the proposed classification. Key features on OCT were identified and analysed for their utility in clinical practice. A final classification was devised based on two sequential, independent validation exercises to improve interobserver variability.

Results: This classification tool pertains to idiopathic focal VMT assessed by a horizontal line scan using SD-OCT. The system uses width (W), interface features (I), foveal shape (S), retinal pigment epithelial changes (P), elevation of vitreous attachment (E), and inner and outer retinal changes (R) to give the acronym WISPERR. Each category is scored hierarchically. Results from the second independent validation exercise indicated a high level of agreement between graders: intraclass correlation ranged from 0.84 to 0.99 for continuous variables and Fleiss' kappa values ranged from 0.76 to 0.95 for categorical variables.

Conclusions: We present an OCT-based classification system for focal VMT that allows anatomical detail to be scrutinised and scored qualitatively and quantitatively using a simple, pragmatic algorithm, which may be of value in clinical practice as well as in future research studies.

Conflict of interest statement

This study group was convened by Alcon, which distributes ocriplasmin in the UK on behalf of Thrombogenics. Neither Thrombogenics nor Alcon had input in the design of the study, manuscript preparation, or editorial review and neither were invited to review the manuscript prior to submission. Steel DHW is a consultant to Alcon and advisor to Novartis and Bayer. Jackson TL is a consultant to Thrombogenics and advisor to Alcon, Bausch & Lomb, and DORC. Yang Y is a consultant to Bayer and Alimera Sciences and advisor to Alcon, Thrombogenics, Allergan, and Novartis. Downey L, Laidlaw DAH, Koshy Z, Heimann H, Wickham L, and Greiner K have acted as advisors to Alcon and Thrombogenics regarding ocriplasmin.

Figures

Figure 1

Schematic representation of the focal VMT classification tool: WISPERR. (a) Width of vitreous attachment (W), interface features (I), and foveal shape (S). (b) Retinal pigment epithelial changes (P), elevation of vitreous attachment (E), and inner and outer retinal changes (R).

Figure 2

Horizontal SD-OCT of a normal fovea. *Note pre-macula bursa.

Figure 3

Examples of minimum linear diameter measurements using SD-OCT slice with maximum hole dimensions. In (a), the minimum linear diameter is on the inner side of the hole and in an eccentric slice without vitreomacular traction, while in (b) it is on the outer retinal side of the hole. (c) A case of apparent outer retinal dehiscence but with a tiny para-central full-thickness macular hole seen on one more eccentric OCT slice in (d). When measuring minimum linear diameter, the area of the retinal operculum should not be included (shown in (e) and (f)).