The preferred shoe type opening for a patient with severe edema is:

For a patient with severe edema, the preferred shoe type opening is one that allows for easy adjustment and provides ample room for swelling. A lace-to-toe design offers the ability to loosen or tighten the shoe at various points along the instep, accommodating fluctuations in foot size due to edema. This flexibility is crucial as it enables the wearer to adjust the fit comfortably throughout the day, which is essential for those experiencing significant swelling.

While Velcro shoes can also be beneficial, they may not provide the same level of precision in fitting as lace-to-toe shoes. These shoes allow for more controlled tension across the top of the foot, which can be particularly important for achieving a customized fit. Balmoral shoes, typically having a more formal style with a closed lacing system, might not offer the same comfort and adjustability for a patient with edema, making them less suitable. Blucher styles, which feature an open lacing system, do provide some adjustability but may not accommodate the size variations as effectively as a lace-to-toe design.

Thus, the lace-to-toe shoe provides the best combination of adjustability and comfort for patients dealing with severe edema.