Presbyopia

Useful Terms

Presbyopia = age-related condition in which it becomes very difficult to see objects and people very close by; also called aging eye, which is the literal translation of presbyopia; becomes conspicuous when in the 40s, age-wise, and will progressively become worse up until the age of 65 or so

Common Symptoms

  • Blurred or inhibited vision at normal reading distances
  • A need to hold reading materials farther away in order to focus in on and see them more clearly
  • Fatigue, eyestrain, and/or headaches resulting from doing close work or reading
  • These symptoms necessitate an immediate response:

    • Sudden vision loss in one of the eyes
    • Sudden hazy, dimmed, or blurred vision
    • Seeing black spots, flashes, or halos around lights

Risk Factors

  • Advanced Age

    • This is the greatest risk factor since just about everyone will experience one form or another of presbyopia after reaching the age of 40 years
  • Co-Occurring Conditions

    • Having other co-occurring conditions such as hyperopia (farsightedness), diabetes, multiple sclerosis, or even other cardiovascular diseases can increase the chances of prematurely contracting presbyopia before the age of 40 years
  • Drugs

    • The usage of some antidepressants, antihistamines, and diuretics makes the development of presbyopia all the more likely

Causes

  • Advanced Age

    • During the youthful years of life, the lens within the eye is flexible, able to adapt its shape very easily with the aid of an adjacent circular muscle

      • Looking at something or someone in the distance (nearby) causes this muscle to loosen (constrict), which gives the lens its elasticity and ability to curve and change its light focusing power as needed
    • As the body ages, the proteins within the lens change in such a way that the lens becomes more rigid, reducing its elasticity and thus its ability to curve and modify its power of light focusing for the purpose of seeing images of things or people close-up
    • Consequently, these close-up images appear to be blurred and out of focus, which leads to the need for people to hold their reading materials farther away in order to see them better
  • Co-Occurring Conditions

    • Those who currently also have myopia, hyperopia, or astigmatism in addition to presbyopia can experience a combination of symptoms from them
    • Interestingly enough, it seems that the co-occurring condition of presbyopia may mitigate the problems that plague those who also have myopia

Diagnosis

  • Comprehensive Eye Examination

    • Presbyopia can be detected in the routine eye examination
    • Letter Charts

      • The patient reads off letters at a certain distance away from the eyes in order to measure visual acuity and clarity
    • Phoropter

      • This is that device in which the patient looks through different sets of lenses and identifies which of the two pairs of lenses in each set offers clearer vision
      • The Phoropter thus helps measure the visual acuity and clarity of both close-up and distance vision
    • Ophthalmoscopy

      • The pupils are dilated with the use of eyedrops so as to allow the effective usage of the ophthalmoscope to magnify and more thoroughly examine the various structures within the eyes
    • It is recommended for adults to have a comprehensive eye examination every:

      • 1) 5 – 10 years for those under the age of 40 years
      • 2) 2 – 4 years for those between the ages of 40 and 54 years
      • 3) 1 – 3 years for those between the ages of 55 and 64 years
      • 4) 1 – 2 years for those at and over the age of 65 years

Treatment

  • The goal is to offset the inability of the eye (s) to properly focus on close-by objects
  • Eyeglasses

    • This is a simple and safe method of treatment
    • Over-the-counter reading glasses may be used for those patients who had good and uncorrected vision before they developed presbyopia

      • Most of these reading glasses range in power from +1 – +3 D (D for diopters, unit of measurement of optical power of lenses)
      • Start at the lower powers and work the way up to and through the higher ones until the patient finds one power that allows him/her the ability to read comfortably
      • Test each pair of reading glasses that are tried on reading materials that are held at a comfortable enough distance
    • Prescription eyeglasses are needed in those cases in which over-the-counter, nonprescription eyeglasses are insufficient or the patient requires the usage of prescription eyeglasses for other co-occurring conditions

      • There may be prescription eyeglasses exclusively for usage when reading
      • Bifocals

        • There are two styles of bifocals:

          • 1) Bifocals with a visible horizontal line
          • 2) Bifocals without a visible horizontal line (also known as progressive lenses)

            • These correct distance vision when looked through at eye level
            • The correction progressively changes into reading correction at the bottom
      • Trifocals

        • These eyeglasses provide improvement for close work, middle-distance vision, for those who work at computers, and distance vision
        • There are two types of trifocals:

          • 1) Trifocals with a visible horizontal line
          • 2) Trifocals without a visible horizontal line (also known as progressive lenses)
  • Contact Lenses

    • These are a viable alternative to eyeglasses, but don’t work for those people who have any eye conditions related to the eyelids, tear ducts, or the surfaces of the eyes
    • There are numerous varieties of contact lenses:

      • 1) Bifocal Contact Lenses

        • Both of the contacts provide correction for close-up and distance vision
        • One type of these particular lenses keeps the bottom, reading portion of the lens weighted so as to keep it properly positioned on the eye

          • These could be difficult to fit, and even if they did, they usually don’t yield any adequate results
        • Newer models may improve distance vision (close-up vision) through the edges of each lens (center of each lens), or vice versa
      • 2) Monovision Contact Lenses

        • The dominant eye gets a contact lens to correct for distance vision, while the other eye gets one to improve close-up vision

          • The dominant eye is that eye that is used when aiming a camera to take a picture
      • 3) Modified Monovision Contact Lenses

        • The dominant eye gets a contact lens to correct for distance vision, while the other eye gets a bi- or multifocal contact lens
        • Both eyes are used for distance vision, while only one is used for reading vision
  • Refractive Surgery

    • This method of treatment is used to change the corneal curvature so as to improve close-up vision in the non-dominant eye

      • It is similar to monovision contact lenses and it is recommended to try monovision contact lenses before going through with the surgery, since it is irreversible
    • Conductive Keratoplasty (CK)

      • Radio waves are used to emit heat to small spots around the cornea in order to marginally shrink the edge of the cornea, thereby improving its curvature and ability to focus light rays for a correction of close-up vision
      • This procedure may prove to be effective, but its effects are usually temporary, which means that presbyopia could recur over time
    • LASIK

      • A small, circular incision is made in part of the cornea to make a flap of sorts
      • A laser is then used to destroy layers from the corneal center as a way of flattening its irregular, domed shape
    • LASEK

      • A small incision is made in the corneal epithelium (serves as the thin and protective cover for the cornea) to make a flap
      • A laser is then used to reshape the outer layers of the cornea by flattening the irregular, domed curvature
      • This is followed by the repositioning of the flap within the epithelium
      • The flap is healed over with the usage of a bandage contact lens over the course of several days after LASEK has been performed
    • Photorefractive Keratectomy (PRK)

      • This surgery follows the same procedure as LASEK, save for the removal of epithelial flap
      • It will grow back naturally on its own with time and adapt itself to the changed corneal shape
      • It too requires the usage of bandage contact lenses for a healing period of several days after the procedure is done
      • The recovery from this procedure is less speedy and more painful than that from LASIK
    • Intraocular Lens Implant (IOL Implant)

      • Lenses are surgically implanted in place of the natural lens within the eye
      • Some may choose to have IOL implants years after having had LASIK surgery just to be free from dependence on reading glasses
      • Some IOL implants may allow the correction of close-up and distance vision in the eye, while others may accommodate by changing their positions or shapes while within the eye
      • They may degrade the close-up vision, which could still necessitate the usage of reading glasses
      • These have possible side effects of glare and blurred vision, as well as those associated with cataract surgery, including swelling, infection, bleeding within the eye, or the onset of glaucoma
    • Corneal Inlays

      • This procedure involves the insertion of a small, plastic ring at the edge of the respective corneas within both of the eyes to change their curvatures
      • Those who have had LASIK surgery before can still qualify to receive this procedure
      • There are less risks and side effects associated with this procedure than with other treatment methods
      • The Eye M.D. can remove these plastic rings with no consequence