A window into the brain: An in vivo study of the retina in schizophrenia using optical coherence tomography

Abstract

Retinal nerve fibre layer (RNFL) thickness and macular volume (MV) can be measured in vivo using optical coherence tomography (OCT) providing a “window into the brain”. RNFL and MV are promising biomarkers in neurological diseases. This study explores the potential of RNFL and MV to detect axonal abnormalities in vivo in schizophrenia and their correlations with clinical features. OCT was performed in 49 patients (38 schizophrenia, 11 schizoaffective disorder) and 40 healthy controls matched for age and gender. Group comparisons were made between whole retina and quadrant RNFL thickness and MV using multi-level analyses. In patients, associations were sought between RNFL and MV with symptom severity (positive/negative). Patients and controls had similar whole retina RNFL thickness (p = 0.86) and MV (p = 0.64), but RNFL in the right nasal quadrant of the schizoaffective group was thinner than in the schizophrenia group (p = 0.02). In patients, positive symptom severity was associated with smaller MV (right β = − 0.54, p = 0.02; left β = − 0.49, p = 0.04). Normal MV and RNFL thickness suggests unmyelinated axons in patients with schizophrenia/schizoaffective disorder remain unaffected. Longitudinal studies using higher resolution OCT will clarify whether progressive RNFL and MV changes occur and whether they can be used as state or trait markers in schizophrenia.

Retinal nerve fiber layer and macular thickness in patients with schizophrenia: Influence of recent illness episodes

“…In the first study reported in the literature, our group found a decreased RNFL thickness as measured with OCT in patients with schizophrenia (Ascaso et al, 2010). Similar results have been later reported by Lee et al (2013), who additionally found a relationship between abnormal OCT parameters and illness duration, but not by Chu et al (2012), who did not find significant differences in retinal parameters between patients in the early stages of illness and controls.…”

Revisiting visual dysfunctions in schizophrenia from the retina to the cortical cells: A manifestation of defective neurodevelopment

“…Indeed, the volume of the macula was reduced, the thickness of both macula and RNFL was decreased and the thinning/reduction were correlated with the duration of the disease (Lee et al, 2013). Using the same technique, another team failed to replicate the thinning of the macular and the RNFL but found that the macular volume was negatively correlated with the severity of positive symptoms (Chu et al, 2012).…”

Decreases in retinal nerve fiber layer and ganglion cell-inner plexiform layer thickness in schizophrenia, relation to insight: a controlled study

“…Bu araştırmada kullanılan OKT aygıtının eski teknolojiye sahip olması, araştırmacılar tarafından da sınırlılık olarak belirtilmiştir. 7 Çalışmamızda kullanılan spektral OKT aygıtı, RSL ve GHIP tabakasını ölçebilmek-tedir. Bu aygıt son dönemde şizofrenide retina tabakalarını araştırmak için kullanılan OKT aygıtlarına benzer teknolojidedir, duyarlı ve iyi çözünürlükte sonuç verebilmektedir.…”

“…3,4 Optik sinirin merkezi sinir sistemi (MSS) ile ortak embriyolojik yapıdan (nöro-ektoderm) köken alması nedeni ile OKT ile ölçülen retina tabaka değişikliklerinin, beyinde oluşan nörodejenerasyonu doğrudan yansıtabi-leceği ileri sürülmüştür. [5][6][7] OKT, Parkinson, bunama, multipl skleroz (MS) gibi MSS hastalıklarının tanı ve izlemelerinde kullanılmaktadır. [8][9][10][11] Şizofreni hastalarında OKT, MSS'nin diğer hastalıklarına göre daha az sayıda araştırmada kullanılmıştır.…”