There are various types of eyeglass prescriptions. Other types of prescriptions include astigmatism and prism correction prescriptions. Warby Parker makes high-quality, stylish eyeglasses, sunglasses, and contacts. Their Home Try-On program lets you try 5 frames for free before ordering. All Vision Center content is medically reviewed and fact-checked by a licensed optometrist to ensure the information is factual and meets industry standards. We have strict sourcing guidelines and only cite from recent scientific research, scholarly articles, textbooks, government agencies, optometry websites, and medical journals.
Updated on October 27, What Is a "Normal" Eye Axis? Medically Reviewed by. Written by. Anthony Armenta. In this article. Vision Center Recommends Warby Parker Warby Parker lets you select 5 frames to test out for 5 days and ships them to you —for free! Learn more. Shop Warby Parker. Related Pages. Gilbert , Michael L. Porter, Daniel. Melody Huang, O. Melody Huang is an optometrist and freelance health writer.
Through her writing, Dr. Huang enjoys educating patients on how to lead healthier and happier lives. She also has an interest in Eastern medicine practices and learning about integrative medicine.
Huang loves reviewing new skin care products, trying interesting food recipes, or hanging with her adopted cats. This indicates the amount of lens power, measured in diopters D , prescribed to correct nearsightedness or farsightedness.
Cylinder CYL — This indicates the amount of lens power for astigmatism and represents the difference in the greatest and weakest powers of the eye, usually separated by 90 degrees. If nothing appears in this column, either you have no astigmatism, or your astigmatism is so slight that it is not necessary to correct it with your eyeglass lenses.
The number in the cylinder column may be preceded with a minus sign for the correction of nearsighted astigmatism or a plus sign for farsighted astigmatism. The degree meridian is the vertical meridian of the eye, and the degree meridian is the horizontal meridian. Axis describes the lens meridian that contains no cylinder power to correct astigmatism.
If an eyeglass prescription includes cylinder power, it also needs to include an axis value, which follows the cylinder power. The axis is the lens meridian that is 90 degrees away from the meridian that contains the cylinder power for astigmatism correction. This is the amount of prismatic power, measured in prism diopters "p.
When present, the amount of prism is indicated in either metric or fractional English units 0. Sphere power, cylinder power and add power always appear in diopters. They are in decimal form and generally are written in quarter-diopter 0. When prism diopters are indicated in decimal form, typically only one digit appears after the period e.
No cylinder power or axis , which means no astigmatism is present. This doctor chose to write "SPH," to confirm the right eye is being prescribed only spherical power. Some doctors will add "DS" for "diopters sphere" and others will leave it blank. A cylinder power with an axis at the meridian. This means that the horizontal degree meridian of the eye has no added power for astigmatism and the vertical degree meridian gets the added Prismatic correction of 0.
In the right eye, the prism is base down BD ; in the left eye, it's base up BU. Your eye doctor may also write specific lens recommendations on your eyeglass prescription.
0コメント