Retinal nerve fiber layer decrease and choroidal layer increase after four weeks of buprenorphine/naloxone maintenance treatment in opioid use disorder

Background and Objectives

Spectral-domain optical coherence tomography (SD-OCT) findings in substance use disorders have been investigated in recent years. In this study, we compared the retinal nerve fiber layer (RNFL), the ganglion cell layer (GCL), the inner plexiform layer (IPL), and the choroid thickness (CT) of OUD and control groups before and after buprenorphine/naloxone maintenance treatment (BN-MT).

Methods

The OUD group consisted of 46 male subjects and the control group consisted of 49 male subjects. Patients with chronic opioid use and opioid positivity in their urine during the initial SD-OCT application were included in the study. At the end of the fourth week of BN-MT, SD-OCT was repeated and BN positivity was detected in the urine of the patients at this time.

Results

There was a significant difference between OUD and control groups in terms of nasal superior and CT values of both eyes (p<0.05) before BN use. The values of RNFL sectors and CT of both eyes before and after BN-MT differed significantly (p<0.05); CT increased and RNFL sectors decreased. After BN-MT, psychometric scales differed significantly in favor of the patients (p<0.05). The SD-OCT values of the OUD group after BN-MT were compared with the control group: the right IPL (p=0.003), the left IPL (p=0.023), the right N (p=0.001) and the left N (p<0.001) values were significantly lower in the OUD group.

Conclusion

This is the first study to show the SD-OCT findings of patients with OUD before and after BN-MT. The findings of this study may indicate possible effects of chronic opioid use in patients and/or possible effects of exogenous opioid or BN present in the body during SD-OCT applications. However, based on our findings, it is not possible to distinguish between the two possible outcomes. The fact that the use of BN acting through opioid receptors has different effects from exogenous opioids may be due to different receptor profiles.