A measure of the tendency of an eyeglass lens material to cause chromatic aberration, which is an optical distortion that causes colored halos or fringes around lights or blurred vision, especially when looking through the periphery of the lens. The lower the Abbe number, the more likely chromatic aberration will be noticeable.These are simple eye care definitions and general information for common eye-related terms that we often use in our office. Explanations are then expanded based on the individual circumstances for each patient. If you wish more extensive web-based eye terminology before or after your examination in our office, review these resources:
Glossary of Eye Care Terms

Eye Care Glossary of Terms

Glossary of All Eye & Vision Conditions

The fluid layer on the eye that helps keep the eye moist and nourished and provides a smooth surface for clear vision. The tears have three main components: a mucin layer is directly on the eye and helps smoothly spread the main watery layer over the eye, and a very thin lipid/fatty molecule layer on top to help slow evaporation.
Nearly clear, lens-shaped tissue behind the iris and pupil that is able to change shape to allow focusing from distance to near. The lens grows like an onion, layer by layer, getting thicker over time. The lens becomes a cataract when it becomes more cloudy or develops opacities.

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