Medivena One-Care Opti Safety Pen Needles. ONE-CARE OPTI Safety Pen Needles offer simple handling in a similar way as major brands, therefore, no special training is required. ONE-CARE OPTI Safety Pen Needles have compact size and provide the nurses with visual indication when the needle is permanently locked - color coded inner shield disappears after safety mechanism engagement. Now you have a choice for patient comfort to encourage glucose testing and treatment, and ultimately drive compliance and reduce cost of diabetes management.