星期二, 九月 11, 2007

Are Phakic Lenses For You?

Are Phakic Lenses For You?


You are probably NOT a good candidate for phakic lenses if:


  • You are not an adult. There are no phakic lenses
    approved by the FDA for persons under the age of 21.
  • You are not a risk taker. Certain complications
    are unavoidable in a percentage of patients, and there are no long-term
    data available for phakic lenses.
  • You required a change in your contact lens or glasses prescription
    in the last 6 to 12 months in order to obtain the best possible vision
    for you.
    This is called refractive instability. Patients
    who are:
    • in their early 20s or younger,
    • whose hormones are fluctuating due to disease such as diabetes,
    • who are pregnant or breastfeeding, or
    • who are taking medications that may cause fluctuations in vision,

    are more likely to have refractive instability and should discuss the
    possible additional risks with their doctor.


  • You may jeopardize your career. Some jobs prohibit
    certain refractive procedures. Be sure to check with your employer/professional
    society/military service before undergoing any procedure.
  • Cost is an issue. Most medical insurance will not
    pay for refractive surgery.
  • You have a disease or are on medications that may affect
    wound healing.
    Certain conditions, such as autoimmune diseases
    (e.g., lupus, rheumatoid arthritis), immunodeficiency states (e.g.,
    HIV) and diabetes, and some medications (e.g., retinoic acid and steroids)
    may prevent proper healing after intraocular surgery.
  • You have a low endothelial cell count or abnormal endothelial
    cells.
    If the cells that pump the fluid out of your cornea,
    the endothelial cells, are low in number relative to your age, or
    if your endothelial cells are abnormal, you have a higher risk of
    developing a cloudy cornea and requiring a corneal transplant.
  • You actively participate in sports with a high risk of eye
    trauma.
    Your eye may be more susceptible to damage should
    you receive a blow to the face or eye, such as a blow to the head
    during boxing or hit in the eye by a ball during baseball. Your eye
    may be more susceptible to rupture or retinal detachment, and the
    phakic lens may dislocate.
  • You only have one eye with potentially good vision. If
    you only have one eye with good vision with glasses or contact lenses,
    due to disease, irreparable damage, or amblyopia (eye with poor vision
    since childhood that cannot be corrected with glasses or contact lenses),
    you and your doctor should consider the risk of possible damage and/or
    loss of vision to your better eye as a result phakic lens implantation.
  • You have large pupils. If your pupil dilates in
    low lighting conditions to a size that is larger than the size of
    the lens, you have a higher risk of experiencing visual disturbances
    after surgery that may affect your ability to function comfortably
    or normally under such conditions (e.g., while driving at night).
  • You have a shallow anterior chamber. If the space
    between the cornea and the iris, the anterior chamber, is narrow,
    you have a higher risk of developing complications, such as greater
    endothelial cell loss, due to implantation of the phakic lens.
  • You have an abnormal iris. If your pupil is irregularly
    shaped you have a higher risk of developing visual disturbances.
  • You have had uveitis. If you have had inflammation
    in your eye, you may have a recurrence or worsening of your disease
    and/or may develop additional complications, such as glaucoma, as
    a result of surgery.
  • You have had problems with the posterior part of your eye.
    If you have had any problems in the back part of your eye
    or are at risk for such problems, for example, proliferative diabetic
    retinopathy (growth of abnormal vessels in the back of the eye due
    to diabetes) or retinal detachment, you may not be a good candidate
    for phakic lens implantation. The phakic lens may not allow your eye
    doctor to get a clear view of the back part of your eye, preventing
    or delaying detection of a new or worsening problem, and/or the phakic
    lens may prevent or make treatment of a problem in the back of your
    eye more difficult.

The safety and effectiveness of phakic lenses have NOT been studied
in patients with certain conditions. If any of the following apply to
you, make sure you discuss them with your doctor:


  • You have glaucoma (damage to the nerve of the eye
    resulting in loss of peripheral and then central vision due to too
    high pressure inside the eye), ocular hypertension
    (high eye pressure), or glaucoma suspect (some indications,
    but not clear, that patient has glaucoma). You may have a higher risk
    of developing or worsening of glaucoma as a result of phakic lens
    implantation.
  • You have pseudoexfoliation syndrome (abnormal deposits
    of material in the eye visible on the structures in the front part
    of the eye, such as on the front of the natural lens and the back
    of the cornea). This syndrome is associated with glaucoma and weakness
    of the structures holding the natural lens in place (the zonules).
    You may have a higher risk of surgical complications and/or complications
    after surgery if you have this syndrome.
  • You have had an eye injury or previous eye surgery.
  • Your need for visual correction is outside the range for
    which the phakic lens has been approved.
    Ask your eye doctor
    if the phakic lens that he or she recommends for you has been approved
    to treat your refractive error and/or check FDA-Approved
    Phakic Lenses
    for the approved refractive range.
  • You are over the age of 45 years old. Some phakic
    lenses have not been studied in patients over the age of 45.

US FDA Are Phakic Lenses for You?

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