Diabetic Retinopathy

Useful Terms

Diabetic retinopathy= one of the most prevalent diabetic eye conditions; occurs when there is a change in the blood vessels in the retina; in one instance, the blood vessels could swell to an abnormal size and leak fluids; in another instance, the blood vessels may close off entirely; and yet in other cases, there may be a growth of abnormal blood vessels on the retinal surface

Nonproliferative diabetic retinopathy (NPDR)= one of the two main types of the disease; this condition is marked by those diabetic retinopathies in which the blood vessels in the retina swell and start to leak fluids and blood into the eye; in some cases, fats or cholesterol deposits may be amongst those fluids that are leaked

Proliferative diabetic retinopathy (PDR)= one of the two main types of the disease; this type is characterized by those diabetic retinopathies in which the blood vessels close off entirely and prevent proper blood flow; the retina attempts to compensate with the growth of new blood vessels, but these new ones are abnormal and do not correct the blood flow; additionally, the new blood vessels could come with        scar tissue that could cause wrinkles in or detachment of the retina

Common Symptoms

  • Symptoms usually will affect both of the eyes
  • Floaters = just as they occur in retinal detachment
  • Blurred or clouded vision
  • Vision that changes occasionally from blurred to clear
  • Blank or darkened areas within the field of vision
  • Impaired vision during the nighttime
  • Impaired color perception
  • Loss of vision

Risk Factors

  • It can happen to anyone who has diabetes, which has three different forms:

    • 1) Type 1 = usually found in children and young adults; the body doesn’t produce insulin
    • 2) Type 2 = the most common of all three types; the body may not produce enough insulin or the cells of the body ignore what insulin is being produced
    • 3) Gestational = glucose levels are increased in women who have never had diabetes before during pregnancy; the body of the mother-to-be is unable to produce and use all of the insulin necessary during pregnancy
  • Duration of Diabetes

    • The risk of either contracting diabetic retinopathy or exacerbating it and its symptoms increases over time
    • 80% of the Type 1 diabetes patients will contract diabetic retinopathy after 15 years
    • As many as 84% of the Type 2 diabetes patients will get the disease after 19 years
  • Poor Maintenance of Blood Sugar Levels

    • A key risk factor and one of the few that the patient can affect
    • Lower levels can delay the contraction of the disease or slow its development
  • High Blood Pressure

    • Effective maintenance of blood pressure may reduce the risk of the evolution of the disease and the loss of visual acuity that comes with it
    • The higher the blood pressure, the more damaged the blood vessels in the retina become and the higher the chance for problems with the eye (s)
    • The target blood pressure to aim for is less than 130/80 mm Hg
  • High Cholesterol

    • The higher the cholesterol and triglyceride levels in the body, the greater the chance that protein deposits called exudates could leak into the retina and the rest of the eye
    • This may all lead to a higher risk of a moderate loss of vision
  • Pregnancy

    • Those who have diabetes and become pregnant are at a greater risk for contracting the disease
    • For those who already have diabetic retinopathy, the condition will worsen
  • Tobacco Usage

Causes

  • NPDR

    • The earliest stage of diabetic retinopathy
    • May cause many changes within the eye:

      • Microaneurysms

        • Small lumps in the retinal blood vessels that contribute to the leakage of fluids
      • Retinal Hemorrhages

        • Small spots of bloods that are leaked into the retina
      • Exudates

        • Leakage of fat and/or cholesterol deposits
      • Macular Edema

        • Fluid leakage causes the macula to swell and thicken
        • As a result, the macula ceases its ability to properly function
        • This is the most common cause of loss of vision for those who suffer from diabetes
      • Macular Ischemia

        • The closing of the capillaries within the retina
        • The lack of proper blood flow in the macula results in blurred or clouded vision
    • Most diabetes patients have a mild form of NPDR and have not had their vision affected

      • Those whose vision were affected were because of the incidence of macular edema and ischemia
  • PDR

    • This form of the condition can cause a more severe loss of vision than NPDR since PDR can impair both the central and peripheral vision
    • Vitreous Hemorrhage

      • The new weak and delicate blood vessels bleed into the vitreous gel, which prevents light from being properly focused onto the retina
      • Those vitreous hemorrhages that are small may result in a few floaters
      • Those vitreous hemorrhages that are large could block out all vision, reducing vision to an extent that the patient can only perceive light and dark
      • This alone is not enough to cause a permanent loss of vision
      • Once the blood clears, the vision may return to its prior level unless the macula has been injured
    • Tractional Retinal Detachment

      • The scar tissue associated with the growth of new blood vessels will result in the wrinkling and detachment of the retina from its regular position
      • This can also lead to the wrinkling of the macula and subsequent distortion of vision
      • As long as the macula and significant portions of the retina are detached, there may be a case of extreme loss of vision
    • Neovascular Glaucoma

      • When the retinal blood vessels are closed, this condition could occur in the iris of the eye
      • New blood vessels can prevent a normal flow of fluids out of the eye
      • As per the usual symptoms of glaucoma in the eye, pressure will build up within, which can cause substantial damage to the optic nerve

Diagnosis

  • Comprehensive Eye Exam

    • This is the only way to detect the disease and oversee its development
    • There are multiple parts to this exam:

      • Eye Charts

        • Reading letters at certain distances with one eye at a time is an excellent way to test for the ability to distinguish the details and shapes of objects at various distances
        • This charts thus help test for visual acuity and clarity
      • Slit-Lamp Microscope

        • This instrument has proven useful in the diagnosis process for various eye conditions and is the same here
        • It helps illuminate the various parts of the eye and produce magnified images of these parts to better locate any abnormalities within the eyelids, conjunctiva, sclera, cornea, iris, lens, retina, optic nerve, and other parts
      • Dilated Eye Exam

        • As with the slit lamp microscope, this procedure is also very useful when it comes to the diagnosis of a plethora of eye maladies
        • Eyedrops are applied to widen the pupils to allow the ophthalmologist to thoroughly inspect the retina and optic nerve for any signs of defects or problems within
      • Fluorescein Angiography

        • This test has also proven useful in diagnosing the incidence of age-related macular degeneration
        • A fluorescein is injected into a vein in the arm and it travels through the body and into the retinal vessels
        • A special camera is used to take pictures of the retina as the dye travels throughout the retina and checks for various signs of the disease, such as:

          • Which of the blood vessels are leaking fluids
          • How much fluid is being leaked
          • How many of the blood vessels are shut off
          • Whether or not there is a growth of new abnormal blood vessels, in a process known as neovascularization
      • Optical Coherence Tomography

        • As with fluorescein angiography, this procedure has proven to be helpful in the diagnosis of age-related macular degeneration and can also help with diagnosing diabetic retinopathy
        • A laser is used to provide a non-invasive, detailed scan of the retina that allows the ophthalmologist to check for signs of macular edema
      • Ultrasound

        • In those cases in which vitreous hemorrhages are present and prevent the doctor from seeing the retina, ultrasound will be used
        • This test can help examine the blood to test for any retinal detachment which, if present near the macula, will obligate immediate surgery
      • The doctor will also check for the presence or absence of cataracts, bleeding in the vitreous, and other general abnormalities
  • Screening Schedule

    • Type 1 diabetes = within five years of diagnosis and then yearly examinations
    • Type 2 diabetes = at the time that diabetes is diagnosed and then yearly examinations = those who have this type of diabetes could have been living with it for some time without having detected anything out of the ordinary and thus have not gone in for a diagnosis
    • Gestational = schedule an appointment during the first trimester of pregnancy because of the rapid development of the disease during the course of pregnancy

 

Treatment

  • The treatment process depends on the type of diabetic retinopathy, how developed it is, and its responses to any prior treatment methods, if applicable
  • Early Stages

    • For those with NPDR, immediate treatment may not be a necessity
    • In that case, an examination is needed to determine the proper course of action
    • Work with the endocrinologist to properly manage diabetes

      • In the early stages of diabetic retinopathy, proper management can retard its development
    • Severe forms of NPDR may also require surgery
  • Advanced Stages

    • For those with PDR, surgery is obligatory promptly
    • Photocoagulation

      • This procedure has proven to be useful with treating retinal detachment and is also the case here
      • An anesthetic eyedrop or injection is first applied to the eye
      • As the patient sits in front of the slit lamp microscope, a contact lens is temporarily put on the eye in order to provide pinpoint accuracy with the focus of the laser beam onto the retina
      • This helps retard or even prevent the leakage of fluids into the retina
      • Additionally, it also decreases the risk of vitreous bleeding
      • Vision could be blurry for up to a day after procedure and laser spots in the center vision may also be observed that can appear after a few weeks, but may not go away entirely
      • If the macula was swelled before surgery, then vision may not be completely recovered, but can still have improvement
      • This laser treatment is applied to all parts of the eye save for the macula
      • Multiple treatments may be necessary over time
    • Panretinal Photocoagulation

      • The areas of the retina that are away from the macular are treated with laser burns
      • This results in the shrinkage and scarring of abnormal blood vessels
      • This treatment can be very effective with preventing the vision loss that comes from the presence of vitreous hemorrhages and tractional retinal detachment
    • Vitrectomy

      • This is another treatment that has helped treat retinal detachment and also helps very much with the treatment of this condition
      • A small incision is made in the eye and the doctor uses special instruments in order to get rid of scar tissue and blood that threatens the occurrence of retinal detachment
      • A gas bubble is placed within the vitreous space and the head is held in various positions to help the retina heal
      • This procedure helps to remove the vitreous hemorrhages and prevent their reoccurrence with the removal of the abnormal blood vessels that caused the leakage
      • The removal of the scar tissue helps the retina reattach to the back wall of the eye
      • This procedure can be combined with laser treatment
    • Medication

      • The major medication for treatment is anti-VEGF
      • VEGF is vascular endothelial growth factor, which is majorly responsible for the growth of the abnormal retinal blood vessels
      • The anti-VEGF medication is injected into the vitreous space after pupil dilation and eye anesthesia have occurred
      • As a result, inflammation and swelling, leakage of fluids, and growth of the abnormal blood vessels are reduced and vision may be improved
      • Treatments may be given at once or as a series at regular intervals of every four to six weeks