Relationships Among Retinal Nerve Fiber Layer Thickness, Vascular Endothelial Growth Factor, and Cognitive Impairment in Patients with Schizophrenia

Abstract

Background Studies have suggested retinal nerve fiber layer (RNFL) involvement in the pathogenesis of schizophrenia. Additionally, research has shown that vascular endothelial growth factor (VEGF) potentially contributes to the pathophysiology of psychiatric disorders. Therefore, this study aimed to investigate VEGF, RNFL, and correlations with cognitive impairments in schizophrenia patients. Methods Patients with schizophrenia (n = 138) were compared to healthy controls (n = 160). RNFLs were measured with optical coherence tomography (OCT). The Stroop color and word test (SCWT) was used to evaluate neurocognition. Blood samples were collected to measure VEGF. SPSS 20.0 was used to perform analysis of covariance, t-tests, partial correlation analysis, and linear regression. Results Thinner RNFLs were found in schizophrenia patients ( p < 0.001). RNFL showed a significant correlation with SCWT scores (all p < 0.05). Serum level of VEGF was lower in patients with schizophrenia ( p = 0.010). Total and inferior RNFL thicknesses of right eyes were positively correlated to VEGF level (RNFL total thickness p = 0.032, inferior thickness p = 0.014).Total RNFL thicknesses were shown to be reduced following a prolonged duration of illness (both p < 0.01). Conclusion These findings suggest that patients with schizophrenia have degeneration with RNFL thickness following illness duration, which may contribute to neurocognitive impairments observed in schizophrenia. VEGF is speculated to play some important role on RNFL degeneration with schizophrenia patients.

Neuropsychological and Clinical Correlations of Optical Coherence Tomography Findings in Patients with Schizophrenia

“…In contrast, not found any correlation between language, attention, delayed memory, and RNFL (31). The other study of the same group reported a significant correlation between RNFL thickness thinning and lower scores on the Stroop Color Word reading test (32). Finally, a recent study examined the correlations between executive functioning, attention, memory/learning and OCT results.…”

“…The authors noted that better cognitive performance was related to a thicker RNFL in only young individuals, but this association diminished in older age groups (30). In schizophrenia, a few studies assessed the cognitive correlations of retinal findings (17,31,32). One study found that lower scores of immediate memory and visuospatial functions of the RBANS (Repeatable Battery for the Assessment of Neuropsychological Status) were correlated with a decline in RNFL thickness.…”

Vascular-related biomarkers in psychosis: a systematic review and meta-analysis

“…In subgroup analysis, only drug-naïve patients displayed decreased NGF (SMD, −2.16; 95% CI, −4.02--0.31; p = 0.022; Table 2), while no significant differences were detected based on other treatment statuses (i.e., unmedicated or medicated), illness stages (i.e., FEP and non-FEP) or sample origins (i.e., plasma and serum). Blood vascular endothelial growth factor (VEGF) level also did not differ between all patients and controls (SMD, 0.11; 95% CI, −0.17-0.39; p = 0.447) (88,90,95,(110)(111)(112)(113)(114)(115)(116)(117). It was decreased in one study with drug-naïve patients (SMD, −0.77; 95% CI, −1.23--0.31; p = 0.001) (111), but not with other treatment statuses, illness stages, or sample origins.…”