Certified Ophthalmic Medical Technologist (COMT) Practice Exam

What is the purpose of adding glycerin and salts to ophthalmic solutions?

1. To improve taste

2. To serve as tonicity agents

3. To enhance color

4. To provide antibacterial properties

The correct answer is: To serve as tonicity agents

The addition of glycerin and salts to ophthalmic solutions primarily serves as tonicity agents. Tonicity is crucial for maintaining the osmotic balance of the solution with that of physiological saline, which is important for ensuring that the solution does not irritate the ocular surface. Using tonicity agents helps to ensure that eye drops are similar in osmolarity to natural tears, promoting comfort and preventing potential damage to the epithelial cells of the cornea and conjunctiva upon application. While enhancing taste, color, or providing antibacterial properties may be beneficial in some contexts, they do not represent the primary role of glycerin and salts in ophthalmic solutions. The primary focus of these components is to ensure that the solution is isotonic, which is vital for patient comfort and the efficacy of the treatment. Ensuring appropriate tonicity facilitates optimal absorption and reduces the risk of adverse effects that could arise from introducing a hypertonic or hypotonic solution to the ocular environment.