Longitudinal observation of OCT imaging is a valuable tool to monitor primary vitreoretinal lymphoma treated with intravitreal injections of methotrexate

BACKGROUND: Developing objective and repeatable indicators to evaluate the efficacy of PVRL treatment is important. The quantification of vitreous cells is a traditional criterion; however slight changes are difficult to ascertain. Spectral domain optical coherence tomography (SD-OCT) is objective, repeatable, and easily explained. The purpose of this study is to provide a longitudinal observation of OCT in PVRL treated with intravitreal injections of methotrexate (MTX) and to evaluate the utility of OCT in monitoring responsiveness of PVRL to treatment. METHODS: The medical records of patients with biopsy-positive PVRL attending our hospital between January 2016 and September 2017 who received intravitreal injections of MTX were included in this study. Pre- and post-treatment OCT images were reviewed independently by two researchers. RESULTS: Of the 24 cases reviewed, 10 patients (18 eyes) were included. SD-OCT abnormalities at the initial visit included vitreous cells (18/18), OR (outer retina) fuzzy borders (12/18), PED (pigment epithelium detachments) (9/18), subretinal hyperreflective infiltration (3/18), intraretinal infiltration (8/18), and SRF (subretinal fluid) (4/18). Post induction treatment, SRF in cases with RD (retinal detachment) was absorbed, and subretinal fibrosis appeared. Other lesions were significantly reduced. Post consolidation treatment, OR fuzzy borders, PED and SRF disappeared in 2 eyes, intraretinal infiltration disappeared in 1 eye, and other abnormalities further improved. Additionally, retinal fibrosis was observed in 3 eyes. One month post maintenance treatment, all abnormalities observed at the first visit vanished. At the last visit, OCT showed subretinal fibrosis and in 3 eyes (16.7%), the disruption of outer retina in 9 eyes (50%) and thinning of the whole layer in 4 eyes (22.2%). CONCLUSIONS: Our observations reveal that characteristic OCT features in PVRL patients can reduce gradually and finally vanish with therapy. We propose that SD-OCT may be employed to monitor the responsiveness of PVRL to treatment, which may influence decision making in the management of this disease.