Abstract
Purpose :
Fractal dimension (FD) analysis of optical coherence tomography angiography (OCTA) has been used to quantify retinal microvascular damage in several retinal vascular diseases. We aimed to evaluate the response to treatment of patients with syphilitic uveitis treated with intravenous penicillin for tertiary syphilis.
Methods :
This was a retrospective case series of patients with syphilitic uveitis who underwent OCTA at presentation and after treatment with intravenous penicillin. Patients were confirmed positive for syphilis with reactive syphilis IgG (>8.0), rapid plasma reagin (RPR) serological tests, and any form of syphilitic uveitis on fundus examination. All patients received intravenous penicillin G 4 million units q4h for 10–14 days. We performed OCTA using Spectralis HRA+OCT (Heidelberg Engineering, Heidelberg, Germany) at presentation before starting treatment and at follow up visit at least 4 weeks later. We excluded eyes that had a low-quality scan before and/or after treatment from the analysis. We processed the raw images initially using contrast limited adaptive histogram equalization (CLAHE) to enhance regional contrasts, followed by a binarization algorithm and fractal analysis using ImageJ (NIH, Bethesda, MD). We performed statistical analysis using IBM SPSS Statistics 26 (IBM Corporation, Armonk, NY). We used the Wilcoxon signed-rank test to compare values before and after treatment.
Results :
We included a total of 14 eyes from 8 patients in this study. FD of the superficial capillary plexus before and after treatment was similar but it was close to statistical significance (p=0.054). After treatment FD of the deep capillary plexus increased in 11 out of 14 eyes from an average of 1.668 to an average of 1.747 (p=0.299). After treatment FD of the choriocapillaris increased in 12 out of 14 eyes improving from an average of 1.763 to an average of 1.869 (p=0.020).
Conclusions :
Fractal analysis of OCTA in patients with syphilitic uveitis showed substantial improvement in the FDs of the choriocapillaris and deep capillary plexus, but not of the superficial capillary plexus, after successful treatment with IV penicillin. This might provide an objective tool for evaluating disease progression and treatment response.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.