INTRODUCTION: Optical coherence tomography (OCT) is used to study retinal structure in schizophrenia. Changes in retinal structure, especially the retinal nerve fiber layer (RNFL) have been correlated with psychotic disorders. Along with a decrease in macular outer nuclear layer (ONL) thickness and an increase in macular outer plexiform layer (OPL). However, measurement variability is a concern for inner retinal layers since there are various generations of OCT devices resulting in differing measurements. We investigated the inter- and intra-device agreement of macular thickness between spectral domain (SD-OCT) and swept source-OCT (SS-OCT), and compared macula and peripapillary group differences in schizophrenia using SS-OCT for inner retinal layers.
Additionally, we expanded on our previous work and investigated whether baseline outer retinal layer data for macular ONL and OPL thickness predicted clinical and cognitive changes in individuals with schizophrenia.
METHODS: For the inter- and intra-scanner study, macular OCT thickness was obtained for schizophrenia (SZ, n=30) and healthy controls (HC, n= 22) subjects using SD-OCT (Heidelberg Spectralis) and SS-OCT (DRI Topcon Triton). Peripapillary thickness was obtained using SS-OCT. RNFL, ganglion cell-inner plexiform complex (GCL+), RNFL+ GCL+ (GCL++), and macular thickness were collected. For the longitudinal study, 7 participants diagnosed with either schizophrenia or schizoaffective baseline OCT measurements and clinical measures were obtained for all 7 participants from study 1, along with 6 months follow up clinical measures. OCT measurements for the macular OPL and ONL were gathered using the Heidelberg Spectralis Clinical and cognitive data was gathered. All statistical analyses were performed using R software.
RESULTS: There was excellent inter-scanner agreement for GCL+ and GCL++ with Interclass correlation coefficient (ICC) values between r =0.92-0.99. Good to excellent intra-scanner agreement was present except for macular RNFL in the SS-OCT device. No significant peripapillary group differences were identified. Poorer (Global Assessment of Functioning) GAF scores were correlated with thinner macular layers. Greater mania symptoms were associated with smaller peripapillary GCL+ thickness (r=-0.43, p=0.03). Poor overall cognition was associated with smaller peripapillary retinal thickness (r=0.36, p=0.02). For the longitudinal study, an increase in baseline OPL thickness was correlated with worse positive symptoms according to the Positive and Negative Symptom Severity(PANSS) at the 6 month follow up (r=0.77, p=0.04) with a trend level effect for PANSS total scores (r=0.71, p=0.08). There was no significant correlation between the change in clinical or cognitive outcomes for 6 months and baseline OPL and ONL thickness.
CONCLUSION: While there is RNFL variability, GCL+ and GCL++ are comparable between scanners SD-OCT and SS-OCT. Given that RNFL thinning is strongly implicated in psychotic disorders, the use of OCT scanners should not be interchanged due to increased RNFL measurement variability. Additionally, though further research is needed on investigating changes in clinical outcomes with changes in OCT measurements, OPL thickness might be a predictor of long-term clinical outcomes or changes in brain pathology for individuals with schizophrenia.
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/43372 |
| Date | 17 November 2021 |
| Creators | Gandu, Swetha |
| Contributors | McKnight, C. James, Lizano, Paulo |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
| Rights | Attribution-NonCommercial-NoDerivatives 4.0 International, http://creativecommons.org/licenses/by-nc-nd/4.0/ |
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