The main disadvantage of acrylic lenses compared to glass lenses is that glass lenses are generally considered to have higher optical quality, with better magnification abilities and resolution.
Acrylic lenses can be subject to yellowing and scratching over time, which can affect visual clarity and performance. Additionally, acrylic lenses can be more prone to distortion in some cases, and their material properties can make them more susceptible to environmental factors like high temperatures and humidity.
Ultimately, the choice between acrylic lenses and glass lenses depends on the specific application and desired properties, as both offer different performance, durability, and affordability benefits.