Measures of Activity: Posterior Segment

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Outcome Measures for Intermediate, Posterior and Panuveitis

The current gold-standard is the NEI Vitreous Haze Score. In this scoring system the patient’s eye is examined with an indirect ophthalmoscope and the appearance compared to a series of photographs representing various degrees of fundal vitreous haze.

This gives rise to a number of limitations, notably that it is:

1) subjective, with only moderate inter-observer agreement;

2) non-continuous, leading to very large steps in disease activity between categories;

3) poorly discriminatory at lower levels of vitreous haze, with most cases of active uveitis being scored at 0.5+ or 1+; and

4) limiting of sensitivity in a clinical trial context (where a two point change is required to be counted as significant).2,3

 

EQUATΘR seeks to address these issues by using Optical Coherence Tomography (OCT) to provide quantitative assessment of the degree of vitreous activity. In 2014 EQUATΘR demonstrated that standard Spectral Domain OCT (SD-OCT) can be used to generate optical density/signal intensity within the vitreous. In a landmark study Objective Measurement of Vitreous Inflammation Using Optical Coherence Tomography of patients with uveitis with varying degrees of vitreous haze and non-uveitic patients, we showed that standard Spectral Domain-OCT images (Spectralis, Heidelberg) could be used to generate an objective measure of vitreous reflectivity, the vitreous:RPE-Relative intensity index, and that this correlated with clinical measures of disease activity but with higher repeatability than the NEI vitreous haze score.

Many forms of uveitis are not associated with significant levels of vitreous haze even when active, so EQUATΘR is also working towards developing novel imaging techniques and analytical protocols to provide objective quantitation of other manifestations of ocular inflammation in the posterior segment of the eye. This includes the major manifestations of inflammation defined by the FDA/NEI Working Group – retinal infiltrates, choroidal infiltrates and retinovascular leakage – and uveitic macular oedema.