Abstract
Purpose :
To grade the severity of anterior uveitis using an enhanced custom-made ocular spot fluorometer for detection of the intensity of light scatter (ILS) from the anterior chamber (A/C) as an objective measure of aqueous flare.
Methods :
The fluorometer, equipped with a lock-in amplifier, was employed in the scatter mode to measure ILS (expressed in mV) from A/C. The instrument was enhanced for higher depth resolution (< 100 µm) and temporal resolution (in excess of 1 kHz). Healthy and pseudophakic eyes were employed as control subjects. ILS was recorded contemporaneously in two cohorts of patients: (a) patients who had undergone phacoemulsification (on postoperative days 1 and 4), and (b) patients diagnosed with uveitis.
Results :
The increased ILS acquisition speed combined with a reduced time constant of the lock-in amplifier (1 msec) led to the elimination of blink-induced artifacts. Increased sensitivity and depth resolution reduced the contribution to ILS from the adjacent intraocular structures. In healthy and pseudophakic eyes, with SUN score of 0, ILS was 0.0783 ± 0.0171 (n = 47) (denoted by S0) and 0.0821 ± 0.0206 (n = 16). In cataract patients, SUN scores rose to 1+ or 2+ after phaco during PO days 1 and 4 with a corresponding ILS of 0.1012 ± 0.0251 (n = 14) (denoted by S1) and 0.1300 ± 0.008 (denoted by S2), respectively. The ILS for anterior uveitis, intermediate uveitis, panuveitis and posterior uveitis were 0.1217 ± 0.0715 (n = 95), 0.1476 ± 0.1016 (n = 49), 0.1794 ± 0.0674 (n = 34) and 0.1600 ± 0.1517 (n = 10), respectively. The different levels of ILS observed with cataract patients, viz., S0, S1, and S2 were then employed to assign pseudo-SUN scores for scoring the severity of inflammation in the uveitis patients. Pseudo-SUN scores showed a better correlation with measured ILS for uveitis patients compared to conventional SUN scores assigned by the clinician.
Conclusions :
The ILS-dependent pseudo-SUN scores, classified based on the severity of inflammation in cataract patients, provided a firm reference to analyze the severity of inflammation in uveitis. Thus, our instrument, which is capable of rapid and sensitive measurements of ILS, can be used in the clinical management of uveitis as well as studies of drug development towards uveitis.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.