Cataracts

Useful Terms

Cataracts = clouding of the typically clear lens (es) of the eye (s)

Common Symptoms

  • Painless cloudy, dimmed, and / or blurred vision
  • Increased difficulty with seeing anything under low light or during nighttime
  • Increased sensitivity to light and glaring
  • Faded or yellowed coloring
  • A need to use brighter lights to be able to read and do other activities
  • Recurrent changes in prescriptions for eyeglasses or contact lenses
  • Double vision in one eye
  • Seeing “halos” around lights

Risk Factors

  • Hereditary = can be passed on to children and future descendants
  • Advanced or elderly age = by age 75, as many as 70% of people will have developed cataracts
  • Diabetes
  • Smoking
  • Obesity
  • High blood pressure
  • Long-term usage of steroids, especially a combination of oral and inhaled steroids
  • Excessive usage of alcohol
  • Extensive exposure of the eyes to sunlight
  • Extensive exposure to ionizing radiation from X-rays or cancer radiation therapy
  • History of eye injury, inflammation, or swelling
  • History of eye surgery

Causes

  • Advanced Age

    • The eye lens is mostly comprised of water and protein
    • Throughout the body’s natural aging process, additional layers form on the surface of the lens and hardens

      • As a result, the lens will lose transparency and flexibility and become thicker
    • The tissues within the lens degenerate and the protein will consequently clump together, resulting in cloudiness in some areas.

      • The lens is responsible for focusing light in such a way so as to produce clear and sharp images onto the retina, which lies behind the lens
      • The cloudiness scatters the light that the lens focuses and reduces the quality of the images that it transmits to the retina
      • Therefore, the vision becomes cloudy, dimmed, and/or blurred
      • This cloudiness is the cataract
  • Nuclear Cataracts

    • These cataracts affect the center of the lens
    • Initially, the vision problems may appear in the form of more nearsightedness, or conversely, a temporary improvement in the reading vision
    • Over time, the lens will gradually yellow in color and result in further cloudiness in the lens
    • Throughout further progression, the cataracts will turn the lens from yellow to brown. The denser yellow or brown colors of the lens will give the patient great difficulty in distinguishing between the different shades of color
  • Cortical Cataracts

    • These cataracts affect the edges of the lens
    • These initially appear as whitish, wedge-shaped streaks on the outer cortex of the lens
    • As the cataracts progress, the streaks will spread and extend to the center of the lens, directly interfering with the focusing of light on the center
    • These particular cataracts are usually responsible for those patients who experience increased sensitivity to glare
  • Posterior Subcapsular Cataracts

    • These cataracts impact the back or rear of the lens
    • At its onset, these start as a small and cloudy area at the back of the lens, which is right in the path that light is focused onto the retina
    • These are the cataracts responsible for impairing vision in bright light, reading vision, and causing glare or the appearance of halos around lights during the nighttime
  • Congenital Cataracts

    • These are the cataracts that are hereditary and passed onto a child or otherwise contracted during early childhood
    • They may also have come about as a result of a contraction of some infection during pregnancy
    • Additionally, they could be caused by other pre- and co-existing conditions, including:

      • Myotonic dystrophy = a type of and the most common form of muscular dystrophy in which the individual experiences progressive wasting and weakness in the muscles
      • Galactosemia = a rare genetic disorder that hampers a person’s ability to metabolize the simple sugar, galactose properly
      • Lowe syndrome = an almost exclusively male genetic disorder that affects the eyes, brain, and kidneys
      • Rubella = a contagious viral infection that is also called three-day measles and is marked by a distinctive red rash
    • They may not always affect vision, but even if they do manage to, they will usually be removed soon after diagnosis
  • Traumatic Cataracts

    • These are caused directly by a previous eye injury
    • They can appear as soon as immediately following the injury or may do so month to years afterward
  • Other Diseases or Surgery

    • Cataracts may also develop because of other afflictions affecting the eye or due to previous eye surgery
  • Cataracts may start in one eye, but can eventually develop in both eyes

    • The cataract in one eye can be more advanced in development than the cataract in the other eye

Diagnosis

  • Check for medical history of eye allergies in the parents
  • Usage of Eye Charts

    • The patient is asked to read letters off of a chart using one eye only while the other is covered as a way to test for visual acuity and clarity
  • Slit Lamp Microscope

    • As with previous eye conditions, a slit lamp microscope can be used to magnify the image of the lens, cornea, iris, and the space between the iris and the cornea
    • This allows for the examination of different parts of the eye in great detail, making it easier to find any abnormalities
  • Retinal Examination

    • The early stages of the disease can be found through the ophthalmologist’s examination of the lens
    • Eye drops are used to widen the pupil in order to allow the doctor to better and more clearly see the retina and the rest of the back of the eye
    • This can be done in conjunction with the usage of the slit lamp microscope or ophthalmoscope to examine the lens for signs of a cataract
    • This may be the only way to know for certain if one has cataract

Treatment

  • Cataracts are one of the most common causes of vision loss
  • A cataract may not need to be removed immediately if it doesn’t significantly affect the lifestyle and ability of the patient to perform certain activities

    • Changes in eyeglasses or prescriptions is all it takes to improve vision
  • A cataract has to be ripe in order to be eliminated = MYTH
  • Once cataracts have been diagnosed, it is recommended to do several things:

    • Come in for an eye exam annually if the patient is older than 65 and biannually if the patient is younger than 65
    • Protect the eyes from extensive exposure to sunlight with the usage of at least 99% UV protection sunglasses and a hat
    • If the patient smokes, then the patient has to quit immediately
    • Use brighter lights for reading and other activities if necessary
    • Severely limit driving at night if glare, halos around lights, or poor night vision are problems
    • Deal with and treat any other co-existing health problems, such as diabetes and high blood pressure
    • Measure the necessary strength of and obtain the eyeglasses or contact lenses that can correct vision

      • If the vision problems become significant enough that it becomes difficult to perform regular activities, then the patient is advised to seek cataracts surgery
  • There are no eyedrops or other medicinal treatments that can remove cataracts; surgery is the only way to get rid of the condition
  • Surgery

    • Prior to surgery, the eye will undergo two different procedures:

      • A-scan = measures the length of the eye
      • Keratometry = measures the curve of the cornea
    • These two measurements help inform the ophthalmologist what the proper intraocular lens implant for the eye should be
    • Previous laser vision correction procedures do not affect the patient’s ability to undergo cataract surgery

      • Previous refractive surgery makes it more difficult to ascertain the best fit intraocular lens (IOL) implant
      • It is recommended to inform the doctor of the patient’s vision prescription prior to any previous eye surgery in order to determine the best fit IOL implant
    • The ophthalmologist will prescribe antibiotic eyedrops to be used 1 – 2 days before surgery in order to decrease the risk of infection
    • With the procedure itself, a small incision is made in the cornea and a small instrument is inserted within

      • This instrument will use high frequency ultrasound to break up the center of the clouded lens, which is then carefully suctioned out
      • The removed clouded lens is replaced with the IOL implant, made of plastic, silicone, or acrylic

        • This IOL implant will allow light to be properly focused onto the retina
        • It becomes a permanent part of the eye
      • Once the IOL implant has been put in place, the incision is closed with or without stitches
    • A protective shield is placed on the eye after surgery
    • Follow the instructions of the doctor as to the proper usage of eyedrops and avoidance of strenuous activity for a certain period of time throughout the recovery period
    • Risks of Surgery

      • Bleeding within the eye
      • Increase of pressure within the eye = glaucoma
      • Swelling or the retina and/or the cornea
      • Detachment of the retina
      • Infection
      • Partial or total loss of vision
      • Secondary Cataract

        • The part of the lens that covers the IOL implant may become clouded anytime afterward in the range of several months to years after the removal of the cataract
        • This results in the secondary cataract
        • If it happens to the patient and blurs vision just as the first one did, then the doctor will use a laser to make another small opening in the center of the clouded lens to allow for light to be properly focused onto the retina again

          • This procedure, which is called posterior capsulotomy, takes only 5 minutes at most to do and requires no recovery period afterwards
    • Those who wear glasses of any kind to correct for near vision may require their usage after surgery for reading, and in some cases, for distance