Objective measurement of vitreous inflammation using optical coherence tomography.
OBJECTIVE
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.


METHODS
Retrospective, observational case-control series.


METHODS
Thirty patients (30 eyes) with vitreous haze secondary to intermediate, posterior, or panuveitis; 12 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 were 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 with that of the retinal pigment epithelium (RPE), generating an optical density ratio with arbitrary units ("VIT/RPE-Relative Intensity").


METHODS
Correlation between clinical vitreous haze scores and OCT-derived measurements of vitreous signal intensity.


RESULTS
The 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). The 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), and AC flare (r = 0.385, P = 0.003). Measurement of VIT/RPE-Relative Intensity showed a good degree of intergrader 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 end point, 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, facilitate monitoring and re-treatment of patients with uveitis in clinical practice.
NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom.
Pearse A
PA
Keane
NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom; Hinchingbrooke Hospital, Hinchingbrooke Health Care NHS Trust, Huntingdon, United Kingdom.
Michael
M
Karampelas
NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom.
Dawn A
DA
Sim
Doheny Eye Institute and Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California.
Srinivas R
SR
Sadda
NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom.
Adnan
A
Tufail
National Eye Institute, National Institutes of Health, Bethesda, Maryland.
H Nida
HN
Sen
National Eye Institute, National Institutes of Health, Bethesda, Maryland.
Robert B
RB
Nussenblatt
Bristol Eye Hospital, University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom.
Andrew D
AD
Dick
Bristol Eye Hospital, University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom.
Richard W
RW
Lee
Academic Unit of Ophthalmology, University of Birmingham, Birmingham, United Kingdom; Birmingham & Midland Eye Centre, Sandwell and West Birmingham NHS Trust, Birmingham, United Kingdom.
Philip I
PI
Murray
NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom.
Carlos E
CE
Pavesio
Birmingham & Midland Eye Centre, Sandwell and West Birmingham NHS Trust, Birmingham, United Kingdom; Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom. Electronic address: a.denniston@bham.ac.uk.
Alastair K
AK
Denniston
D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012189:Retrospective Studies; D041623:Tomography, Optical Coherence; D014605:Uveitis / Q000473:pathology*; D014792:Visual Acuity; D014822:Vitreous Body / Q000473:pathology*