A patient with symptoms of poor tear exchange needs to adjust what aspect of their lens?

When a patient is experiencing symptoms of poor tear exchange, adjusting the optical zone of their lens can be key in enhancing comfort and lens performance. Decreasing the optical zone effectively reduces the total area of the lens that comes into contact with the tear film. This modification can help alleviate some of the issues associated with inadequate tear exchange by facilitating better tear movement beneath the lens and promoting a more effective tear film underneath.

Additionally, a smaller optical zone can lead to an increased curvature of the lens margins. This change can enhance the interaction with the natural tears, potentially leading to an improved exchange rate. It enhances the lens fit and improves comfort, allowing tears to flow more freely beneath the lens.

The other choices do not directly address the issue of tear exchange. While switching to a different lens material or multi-purpose solutions may help some patients experiencing dryness, they do not necessarily address the mechanics of tear exchange governed by the shape and surface area of the lens. Increasing the optical zone could further complicate tear exchange by reducing the amount of space for the tears to flow under the lens. Hence, adjusting the optical zone downwards is the most effective approach for improving tear exchange in this scenario.