The longitudinal follow-up of a newly proposed OCTA imaging finding (SSPiM) and the importance of it as a new biomarker for treatment response in diabetic macular edema.

PURPOSE: This study aimed to evaluate the frequency of SSPiM (suspended scattering particles in motion), systemic risk factors, ocular findings, progression characteristics, and treatment response in diabetic retinopathy (DR) patients.

METHODS: In this prospective study, a total of 109 eyes of 109 patients with diabetic macular edema (DME) were included. Demographic characteristics and systemic data of the patients were recorded. In addition to a detailed ophthalmological examination, optical coherence tomography (OCT) and OCT angiography (OCTA) imaging were performed. According to the OCTA images, the patients were divided into two categories: SSPiM detected (SSPiM +) and undetected (SSPiM -). The patients were followed up at 0, 3, and 6 months. Treatment responses at 6 months in treatment-administered patients with and without SSPiM were examined.

RESULTS: The frequency of SSPiM in DME cases was found to be 34.9%. No significant correlation was found between SSPiM and demographic characteristics, systemic, and biochemical parameters (p > 0.05). It was observed that SSPIM was most frequently localized in the outer nuclear layer adjacent to the outer plexiform (81.6%). SSPiM appearance disappeared in 7 (19.4%) of 36 patients with SSPiM who had regular follow-up for 6 months. In 4 (11.1%) of these seven patients, hard exudate plaques developed in the areas where SSPiM disappeared. Regarding treatment response at 6 months, the decrease in CMT was statistically significantly lower in the SSPiM group compared to cases without SSPiM.

CONCLUSION: SSPiM is a finding seen in approximately one-third of DME patients and may adversely affect the response to the treatment.