GL.Lines only showing in one eye

using UnityEngine;
using System.Collections;
using System;
using System.Collections.Generic;

// Must be attached to the camera so that OnPostRender gets called
namespace BGE
{
    public class LineDrawer : MonoBehaviour
    {
        struct Line
        {
            public Vector3 start;
            public Vector3 end;
            public Color color;
            public bool isDebug;
            public Line(Vector3 start, Vector3 end, Color color, bool isDebug)
            {
                this.start = start;
                this.end = end;
                this.color = color;
                this.isDebug = isDebug;
            }
        }

        static List<Line> lines = new List<Line>();

        Material lineMaterial;

        // Use this for initialization
        void Start()
        {
        }

        void Awake()
        {
            DontDestroyOnLoad(this);
        }

        public static void DrawLine(Vector3 start, Vector3 end, Color colour)
        {
            lines.Add(new Line(start, end, colour, false));
        }

        public static void DrawTarget(Vector3 target, Color colour)
        {
            float dist = 1;
            DrawLine(new Vector3(target.x - dist, target.y, target.z), new Vector3(target.x + dist, target.y, target.z), colour);
            DrawLine(new Vector3(target.x, target.y - dist, target.z), new Vector3(target.x, target.y + dist, target.z), colour);
            DrawLine(new Vector3(target.x, target.y, target.z - dist), new Vector3(target.x, target.y, target.z + dist), colour);
        }

        public static void DrawSquare(Vector3 min, Vector3 max, Color colour)
        {
            Vector3 tl = new Vector3(min.x, min.y, max.z);
            Vector3 br = new Vector3(max.x, min.y, min.z);
                
            LineDrawer.DrawLine(min, tl, colour);
            LineDrawer.DrawLine(tl, max, colour);
            LineDrawer.DrawLine(max, br, colour);
            LineDrawer.DrawLine(br, min, colour);
        }

        public static void DrawCircle(Vector3 centre, float radius, int points, Color colour)
        {
            float thetaInc = (Mathf.PI * 2.0f) / (float)points;
            Vector3 lastPoint = centre + new Vector3(0, 0, radius);
            for (int i = 1; i <= points; i++)
            {
                float theta = thetaInc * i;
                Vector3 point = centre + 
                    (new Vector3((float) Math.Sin(theta), 0, (float) Math.Cos(theta)) * radius);
                DrawLine(lastPoint, point, colour);
                lastPoint = point;
            }
        }

        public static void DrawVectors(Transform transform)
        {
            float length = 20.0f;

            DrawArrowLine(transform.position, transform.position + transform.forward * length, Color.blue, transform.rotation);
            DrawArrowLine(transform.position, transform.position + transform.right * length, Color.red, transform.rotation * Quaternion.AngleAxis(90, Vector3.up));
            DrawArrowLine(transform.position, transform.position + transform.up * length, Color.green, transform.rotation * Quaternion.AngleAxis(-90, Vector3.right));
        }

        public static void DrawArrowLine(Vector3 start, Vector3 end, Color color, Quaternion rot)
        {
            lines.Add(new Line(start, end, color, false));

	        float side = 1;
	        float back = -5;
	        Vector3[] points = new Vector3[3];
            points[0] = new Vector3(-side, 0, back);
            points[1] = new Vector3(0, 0, 0);
            points[2] = new Vector3(side, 0, back);
	
	        for (int i = 0 ; i < 3 ; i ++)
	        {
		        points[i] = (rot * points[i]) + end;
	        }

            lines.Add(new Line(points[0], points[1], color, false));
            lines.Add(new Line(points[2], points[1], color, false));
        }

        void CreateLineMaterial()
        {
            if (!lineMaterial)
            {
                lineMaterial = new Material("Shader \"Lines/Colored Blended\" {" +
                    "SubShader { Pass { " +
                    "    Blend SrcAlpha OneMinusSrcAlpha " +
                    "    ZWrite Off Cull Off Fog { Mode Off } " +
                    "    BindChannels {" +
                    "      Bind \"vertex\", vertex Bind \"color\", color }" +
                    "} } }");
                lineMaterial.hideFlags = HideFlags.HideAndDontSave;
                lineMaterial.shader.hideFlags = HideFlags.HideAndDontSave;
            }
        }

        void OnGUI()
        {
            //Debug.Log("On post render called");
            CreateLineMaterial();
            // set the current material
            lineMaterial.SetPass(0);
            GL.Begin(GL.LINES);
            foreach (Line line in lines)
            {
                GL.Color(line.color);
                GL.Vertex3(line.start.x, line.start.y, line.start.z);
                GL.Vertex3(line.end.x, line.end.y, line.end.z);
            }
            GL.End();
            lines.Clear();
        }
    }
}