An Investigation of the Visual Function in Maintenance Stage of Treatment with Methadone in Drug Addicted Individuals

Visual functions are one of the most important factors influencing daily activities of an individual life. Some medications, however, may affect visual function.Methadone is one of the medications used in drug withdrawal both in detoxification and maintenance stages. Evaluation of visual functions in response to continuous use of methadone is essential to increase our understanding of the methadone effects and improve visual care in these patients, which is the goal of the present study.
In this case control study, 30 drug addicts admitted to drug withdrawal clinicswith mean age of 40.97 (SD=9.90) years were divided into two groups. The case group (with methadone consumption of more than six months) contains 20 addicts and control group (with individuals who has just entered the maintenance stage of drug withdrawal) contains 10 addicts. Several visual function examinations performed: visual acuity, contrast sensitivity, visual field, and stereopsis.
In this study, no significant differences were found between groups in static visual acuity and visual field. Contrast sensitivity in 3(p=0.03), 6 (p=0.001), and 18(p=0.00003) cycle per degree frequencies were statistically significant between groups. Stereopsis also reduced in response to prolonged use of methadone (p=0.04). Also, refractive errors in control group were 1D more minus compared to the case group.
Because methadone is used for a long period of time in the maintenance stage of the drug withdrawal, problems caused by this medicine must be considered and necessary visual care in this field should be provided.