EVALUATION OF OPTICAL COHERENCE TOMOGRAPHY AND ULTRASOUND B-SCAN PARAMETERS IN VARIOUS STAGES OF RETINITIS PIGMENTOSA IN DIFFERENT AGE GROUPS

Abstract

Purpose – to investigate the diagnostic capabilities of optical coherence tomography (OCT) and ultrasound B-scan imaging for assessing structural changes at different stages of retinitis pigmentosa (RP) in various age groups.

Material and Methods
A total of 74 patients (148 eyes) diagnosed with RP were included in the study. The patients were divided into three age groups. According to the severity of the dystrophic process, three stages of RP were identified, and patients in each age group were further subdivided into three subgroups. Subgroup I consisted of patients with an early stage of the disease, subgroup II included patients with a moderately severe stage, and subgroup III comprised patients with a severe stage of RP. All patients underwent routine ophthalmological examinations as well as additional instrumental investigations. OCT was performed using the Topcon 3D OCT-1 Maestro2 system (Topcon Corporation, Japan). Ultrasound B-scan examination was carried out using a Quantel Medical Compact Touch A/B scanner (France) equipped with a 15-MHz probe.

Results
According to OCT findings, in all age groups at the early stage of RP, central retinal thickness (CRT) values were comparable to those of the control group. In patients of subgroups II and III, CRT values were significantly reduced, with the most pronounced decrease observed in subgroup III. Specifically, CRT values in subgroup III were 126 ± 11 μm in group I, 119 ± 7 μm in group II, and 101 ± 15 μm in group III (p < 0.001). In terms of qualitative changes, in all age groups, subgroup I demonstrated a normal retinal layer architecture with overall preservation of the ellipsoid zone (EZ). In subgroup II, moderate thinning of the retinal layers was observed, with partial preservation of the EZ. In subgroup III, marked thinning of the retinal layers was noted, with loss of most of the EZ.

Based on B-scan findings, various degrees of vitreous body (VB) alterations were detected. In all age groups, subgroup I patients demonstrated no echographic changes in the VB. In subgroup II patients, fine dispersed opacities of varying extent were observed within VB. Posterior hyaloid membrane detachment (PHMD) was visualized in 7 of 10 patients (70%) in group I, 10 of 12 patients (83.3%) in group II, and 8 of 10 patients (80%) in group III. Thickening of the posterior hyaloid membrane (PHM) was detected in 2 of 10 patients (20%) in group I, 2 of 12 patients (16.7%) in group II, and 3 of 10 patients (30%) in group III. In subgroup III patients, fine dispersed vitreous opacities were predominantly visualized in a diffuse pattern. PHMD was observed in all cases. Thickening of the PHM was detected in 4 of 7 patients (57.2%) in group I, 7 of 10 patients (70%) in group II, and 5 of 7 patients (71.4%) in group III.

Conclusion
In patients diagnosed with RP, the use of modern non-invasive imaging modalities such as OCT and ultrasound B-scan is valuable due to their high accuracy and informativeness in assessing disease progression and treatment effectiveness. These methods have significant diagnostic and prognostic value in the monitoring of RP. Thus, OCT and ultrasound B-scan imaging may be effectively applied to evaluate the severity of the dystrophic process, perform dynamic follow-up, and assess treatment outcomes in patients with RP.