Abstract
Purpose :
Grading of intraocular inflammation in uveitis is based on clinical signs which are highly susceptible to inter-observer variation. Laser flare photometry represents an objective analysis, however, it is available to few ophthalmic clinics. Optical coherence tomography (OCT), on the other hand, has become an indispensable part of routine ophthalmic examination. In the current study we investigated if standard OCT macular scans can be used to measure intraocular inflammation in patients with unilateral acute anterior uveitis (AAU).
Methods :
Ten adult patients (seven women and three men; age range: 22-63 years) diagnosed with unilateral AAU at the Department of Ophthalmology at Oslo University Hospital were included. Patients underwent a routine ophthalmic examination including fundoscopy and standard radial OCT scans of the macula. Anterior chamber inflammation was objectively quantified using laser flare photometry. Nidek OCT imaging software was used to define image lines corresponding to the internal limiting membrane, the IS/OS and the RPE/BM. ImageJ was then used to segment the OCT images into two regions of interest (ROI): 1) the area anterior to the internal limiting membrane represented by the vitreous body; and 2) the retinal area between the IS/OS and RPE/BM lines. A normalized image whiteness ratio (R) was defined by dividing the image whiteness scores obtained by ImageJ in ROI 1 by ROI 2.
Results :
Four of the ten patients had SUN criteria grade three or higher anterior chamber cells, whereas three patients had inflammatory cells in the anterior part of the vitreous body. Laser flare photometry values in the sick eye ranged from 5.5 to 455. The ratio R in the sick eyes ranged between 0.142 and 0.301, whereas in the healthy eyes it ranged between 0.117 and 0.228 (paired sample T-test p-value=0.045). In nine of the ten patients the ratio R was higher in the sick eye compared to the healthy eye. Upon follow-up during treatment, the ratio R showed a delayed response compared to the laser flare photometry measurements, with an initial worsening before improvement.
Conclusions :
Standard OCT macular radial scans can be used to indicate intraocular inflammation in unilateral anterior uveitis. It could represent an easily accessible method of objective grading of intraocular inflammation.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.