Corneal confocal microscopy (CCM) is a novel technique allows for the quantification of small fibers located near the center of the cornea. CCM is non-invasive and fast, and might be a useful method to confirm small nerve fiber pathology. Our objective was to assess corneal small nerve fiber morphology in patients with chronic pelvic pain (CPP) and to determine the prevalence of SFN in patients with chronic pelvic pain using CCM. 
Aims of the study:
To evaluate the morphology of corneal small nerve fibers in patients with chronic pelvic pain syndrome (CPPS) and to determine the prevalence of small fiber neuropathy (SFN) in this group.

This was a cross-sectional observational study aimed at evaluating corneal small nerve fiber morphology in patients with chronic pelvic pain (CPP) and determining the prevalence of small fiber neuropathy (SFN) in this population.
The study included 27 patients with CPP who were either unresponsive to initial treatment or had comorbid pain syndromes, along with 10 healthy controls.
All participants completed standardized questionnaires assessing symptoms of CPP, including a neuropathic pain questionnaire, to map clinical characteristics.
Corneal imaging was performed using in vivo confocal microscopy (IVCM). Measurements of corneal nerve thickness and dendritic cell density were conducted by a single ophthalmologist blinded to the clinical diagnosis.
Outcome Measures:
Corneal stromal nerve thickness (quantified in micrometers).
Dendritic cell density (cells per square millimeter).
Prevalence of SFN based on IVCM findings.
Additional Analysis:
Longitudinal data were analyzed to assess whether corneal microscopic changes (nerve thickness and dendritic cell density) varied over time in response to CPP treatment.
Statistical Methods:
Group comparisons between CPP patients and controls were performed using independent t-tests for continuous variables. A p-value < 0.05 was considered statistically significant.

In patients with CPPS, the mean stromal nerve thickness was 4.8 ± 1.0 micrometers, which was significantly lower than that of the control group (6.0 ± 1.3 micrometers, p = 0.01).
Dendritic cell density was significantly higher in patients with CPPS: 10 ± 2 vs. 3 ± 1 in controls (p = 0.01).
73% of patients with CPPS showed evidence of SFN as measured by CCM.
Comorbid conditions such as chronic prostatitis, irritable bowel syndrome, fibromyalgia and others were frequently observed in patients with CPPS.

Additional analysis showed that the microscopic pattern of the cornea (nerve thickness and dendritic cell density) did not change with treatment for chronic pelvic pain syndrome.
This supports the hypothesis that corneal changes may be a stable marker of the SFN, independent of current status or therapy for CPPS.

Small fiber neuropathy plays an important role in the pathogenesis of chronic pelvic pain.
Corneal confocal microscopy is a useful non-invasive method to diagnose SFN in patients with CPPS.
The results emphasize the potential of CCM as a tool for early diagnosis and monitoring of SFN, as well as for studying the pathophysiological mechanisms of chronic pain.
The lack of changes in the microscopic picture in the background of treatment indicates the need for further studies to identify possible pathogenetic links between SFN and CPPS.

Continence 15S (2025) 102046
DOI: 10.1016/j.cont.2025.102046