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Tag: astigmatism

Posted on by Dr. Melody Tong

What does my eye prescription mean?

Photo by Josh Calabrese on Unsplash

Eyeglass and contact lenses prescriptions can contain components and abbreviations that may be harder to decipher. Here are some of the common abbreviations and what they mean:

  • OD: or oculus dexter refers to your right eye
  • OS: or oculus sinister refers to your left eye
  • SPH: is the sphere and refers to the lens power required to help correct your vision. A (-) negative
    indicates nearsightedness and (+) positive indicates farsightedness
  • CYL: is the cylinder and refers to how much astigmatism you have if any. Astigmatism is caused
    by a cornea or lens that has a different shape than normal and multiple focal points.
    Astigmatism is very common.
  • AXIS: a number between 1 and 180, indicates exactly where the astigmatism appears on your
    eye
  • ADD: stands for the additional lens power needed to make it easier for you to read. This is seen
    on prescriptions for reading glasses or the lower portion of bifocal/progressive lenses
  • BO, BI, BU, BD stand for base out, base in, base up, and base down. These refer to the position
    of the prism on eyeglasses that correct double vision

For contact lenses you may see additional information such as the brand, mode of wear, and BC +
DIA.

  • BC: The base curve is the measurement that indicates the curvature and shape of your contact
    lenses. This is taken when the steepness or flatness of your cornea is measured.
  • DIA: The diameter is the measurement of the length that your contacts need to be to
    completely cover your cornea.
Posted on by Dr. Sherman Tung

Interested in Refractive Eye Surgery?

Photo credit: iris.ca

In the case of nearsightedness, farsightedness, astigmatism, or presbyopia refractive surgery can help either reduce or eliminate the need for glasses/contacts and improve vision. Good candidates include:

  • Patients with stable unchanging refractive errors
  • Patients with thick healthy corneas and good overall ocular health
  • Patients whose lifestyle/expectations match the surgery they choose

Candidates may have limited options or should avoid refractive surgery if they have:

  • thin corneas
  • severe dry eye
  • extreme levels of myopia, hyperopia, or astigmatism
  • corneal scars
  • cataracts
  • history of eye infections or an active eye infection
  • diabetes
  • glaucoma

What to expect with refractive eye surgery

Before your surgery, your optometrist will:

  • Discuss options and expectations associated with the different types of refractive eye surgery
  • Test your vision
  • Measure the surface and thickness of your cornea
  • Double check if any other existing conditions may complicate or prevent a successful outcome

During your surgery, your doctor will:

  • Instill numbing eye drops
  • Instill devices around your eyelids to prevent blinking
  • Have the patient will stare at a target light to prevent from moving
  • Clicking sounds, duration, other details may vary between different types of surgeries

After your surgery, you will:

  • Use a see through shield to protect your eye while it heals for a few days
  • Apply eye drops to reduce dryness and promote healing
  • Experience varying amounts of scratchy/burning sensations temporarily

Be sure to discuss with your eye care provider about the varying types of refractive surgery options and if they are right for you. Some of these include: LASIK, PRK, ICL, LRI, SMILE etc.