Purpose:
Proposed treatment for cocaine abuse may cause peripheral visual field disturbances. The aim of this study is to assess baseline PVF performance in cocaine abusers prior to initiation of treatment.
Methods:
Humphrey Field Analyzer (HFA) 60-4 program was performed in two independent populations (18 subjects in group 1 and 185 subjects in group 2) who actively abuse cocaine prior to enrolling in a therapeutic trial. Reliable PVF tests were included (fixation loss, false positive and negative <33%). The 60 test points were labeled with a NTSI (nasal/temporal/superior/inferior) coordinate system. Points were organized into inner, middle, and outer eccentricity rings and divided into 4 zones: superior, inferior, nasal, and temporal. The threshold visual sensitivity (TVS) was analyzed by points, rings and zones. One-way ANOVA followed by Tukey’s test was used for analyses.
Results:
All subjects had a normal visual acuity, slit lamp and fundus exam on comprehensive ophthalmic evaluation. Points with the highest TVS and least variability were detected in the inner ring and in the temporal area of the middle ring (Table). Points with the lowest TVS and highest standard deviation were located in the nasal area of the outer ring. The mean zone TVS decreased with increasing eccentricity. The superior zone of the middle ring also displayed high data variability.
Conclusions:
Data from two independent populations suggest that subjects abusing cocaine are able to perform reliable HFA 60-4 testing. Patterns of visual field sensitivities are similar to normal healthy volunteers in another study. Our data support the relevance of PVF testing during trials using medications with possible peripheral visual adverse effects.
Clinical Trial:
www.clinicaltrials.gov NCT00611130
Keywords: visual fields • clinical research methodology • drug toxicity/drug effects