Objective Measurement of Vitreous Inflammation Using Optical Coherence Tomography

Abstract

Purpose To obtain measurements of vitreous signal intensity from optical coherence tomography (OCT) image sets in patients with uveitis, with the aim of developing an objective, quantitative marker of inflammatory activity in patients with this disease. Design Retrospective, observational case-control series. Participants Thirty patients (30 eyes), with vitreous haze secondary to intermediate, posterior, or panuveitis; twelve patients (12 eyes) with uveitis but without evidence of vitreous haze; and 18 patients (18 eyes) without intraocular inflammation or vitreoretinal disease. Methods Clinical and demographic characteristics were recorded, including visual acuity (VA), diagnosis, and anatomic type of uveitis. In each eye, the anterior chamber (AC) was graded for cellular activity and flare according to standardized protocols. The presence and severity of vitreous haze was classified according to the National Eye Institute system. Spectral domain OCT images were analyzed using custom software. This software provided an “absolute” measurement of vitreous signal intensity, which was then compared to that of the retinal pigment epithelium (RPE), generating an optical density ratio with arbitrary units (“VIT/RPE-Relative Intensity”). Main Outcome Measures Correlation between clinical vitreous haze scores and OCT-derived measurements of vitreous signal intensity. Results VIT/RPE-Relative Intensity was significantly higher in uveitic eyes with known vitreous haze (0.150) than in uveitic eyes without haze or in healthy controls (0.0767, p=0.0001). VIT/RPE-Relative intensity showed a significant, positive correlation with clinical vitreous haze scores (r=0.566, p=0.0001). Other ocular characteristics significantly associated with VIT/RPE-Relative Intensity included VA (r=0.573, p=0.0001), AC cells (r=0.613, p=0.0001), AC flare (r=0.385, p=0.003). Measurement of VIT/RPE-Relative Intensity showed a good degree of inter-grader reproducibility (95% limits of agreement: −0.019 to 0.016). Conclusions These results provide preliminary evidence that OCT-derived measurements of vitreous signal intensity may be useful as an outcome measure in patients with uveitis. If validated in future studies, such measures may serve as an objective, quantitative disease activity endpoint, with the potential to improve the “signal:noise” ratio of clinical trials in this area, thus enabling smaller studies for the same power. The incorporation of automated vitreous analysis in commercial OCT systems may, in turn, greatly facilitate monitoring and retreatment of patients with uveitis in clinical practice.

A systematic review and economic evaluation of adalimumab and dexamethasone for treating non-infectious intermediate uveitis, posterior uveitis or panuveitis in adults

“…AC cell grade and VH grade). 36 The SUN system was a formalisation and adoption of the Nussenblatt scale. 8,37 Grading requires the examination of a patient's eye by an indirect ophthalmoscope followed by a comparison of the appearance with a series of photographs of varying grades of fundus VH.…”

“…8,37 Grading requires the examination of a patient's eye by an indirect ophthalmoscope followed by a comparison of the appearance with a series of photographs of varying grades of fundus VH. 37 Although the grading system is accepted by the US Food and Drug Administration and has been used in a number of recent studies of uveitis, 36 it is a subjective grading of cloudiness in the vitreous humour caused by inflammatory cells and cell debris on a non-continuous scale (0, 0.5+, 1, 2, 3 and 4+). 7,8,34,37 Its poor discriminatory property for detecting changes in the lower VH grades and extensive inter-rater variations have been reported to be limitations of this system.…”

“…7,8,34,37 Its poor discriminatory property for detecting changes in the lower VH grades and extensive inter-rater variations have been reported to be limitations of this system. 29,36,38 Inflammation in the AC is assessed on the basis of the number of cells per one field on standard slit-lamp examination or by high-speed optical coherence tomography. 8 Complications of structural changes in the eye as a result of uveitis are typically reported according to the type of complication.…”

Automated segmentation and quantification of airway mucus with endobronchial optical coherence tomography

“…Although pixel intensity has been used to characterize fluid particulate in other OCT applications [30], it is nevertheless not ideal in analyzing mucus due to the fact that dense and heterogeneous distributions of mucus can cause strong scattering effects that can impact the accuracy of the measurements. To compensate for this, we calculate a second-order statistic based on the occurrences of relationships between local pixel pairs using GLCM Contrast.…”

Structural changes of the choroid in sarcoid- and tuberculosis-related granulomatous uveitis

“…[15][16][17] Several early studies have indicated how OCT-derived choroidal images can be useful in uveitic disorders. For example, OCT has been used (1) to describe characteristic features of specific uveitis entities, including thinning of Haller's large vessel layer of the choroid in idiopathic panuveitis and extra-macular choroidal changes in birdshot chorioretinopathy; 18,19 (2) to identify distinct stages of a disease process as illustrated by punctate inner choroidopathy; 20,21 (3) objective measurement of vitreous inflammation; 22 and (4) to monitor response to therapy, exemplified by a reduction of subfoveal choroidal thickening with corticosteroid therapy in Vogt-KoyanagiHarada disease. 23 Additionally, the potential of OCT angiography in uveitic diseases has yet to be realised.…”