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Title: Diabetic Retinopathy: Pathophysiology, Diagnosis, Management and Treatment


1
Diabetic RetinopathyPathophysiology,
Diagnosis, Management and Treatment
  • C. A. Ferreira, M.D.
  • August 4, 2004
  • Diseases of the Eye Conference
  • Region VII Rehabilitation Continuing Education
    Program

2
Diabetes
  • Defined as a group of metabolic disorders
    characterized by hyperglycemia resulting from
    defects in insulin secretion, insulin action, or
    both
  • Diabetes can be associated with serious
    complications and premature death
  • Heart disease, Stroke, Hypertension
  • Retinopathy
  • Nephropathy
  • Neuropathy
  • Amputations
  • Periodontal disease
  • Complications of pregnancy
  • Diabetic ketoacidosis and Hyperosmolar coma
  • Susceptibility to infections

3
Diabetes
  • 1.3 million new cases of diabetes is diagnosed
    per year in people 20 yrs
  • Diabetes was the 6th leading cause of death
    listed on US death certificates in 2000 (213,062
    deaths)
  • Risk for death among people with diabetes is 2
    times that of people without diabetes
  • American Diabetes Association National Diabetes
    Fact Sheet, 1999-2001 National Health Interview
    Survey

4
Diabetes
  • Prevalence of total diabetes in the US, of all
    ages was 18.2 million, (6.3 of the population)
    in 2002
  • Prevalence among people lt 20 yrs was 206,000,
    0.25 of all people in this age group
  • Approximately 1 in every 400-500 children and
    adolescents has Type 1 DM
  • Type 2 DM is becoming more common among Native
    American/American Indian, African American, and
    Hispanic and Latino children and adolescents
  • Prevalence of total diabetes in the US, among
    people 20 yrs was 18 million, 8.7 of all
    people in this age group
  • Among people 60 yrs, 8.6 million, 18.3 of all
    people of this age group
  • American Diabetes Association National Diabetes
    Fact Sheet, 1999-2001 National Health Interview
    Survey

5
Diabetes
  • Prevalence of total diabetes by ethnicity among
    people 20 yrs in the US in 2002
  • Non-hispanic whites 12.5 million, 8.4 of this
    group
  • Non-hispanic blacks 2.7 million, 11.4 of this
    group
  • 1.6 times more likely to develop diabetes than
    non-Hispanic whites of similar ages
  • Hispanic/Latino Americans 2 million, 8.2 of
    this group
  • 1.5 times more likely to develop diabetes than
    non-Hispanic whites of similar ages
  • American Indians and Alaska Natives 107,775,
    14.5. of this group
  • 2.2 times more likely to develop diabetes than
    non-Hispanic whites of similar ages
  • American Diabetes Association National Diabetes
    Fact Sheet, 1999-2001 National Health Interview
    Survey

6
Diagnosis of Diabetes Mellitus
  • The American Diabetes Association Diabetes Expert
    Committee recommends a diagnosis of diabetes when
    one of three criteria is met in non-pregnant
    adults
  • Random plasma glucose of 200 mg/dL, plus
    classic signs and symptoms of diabetes, i.e.
    polydipsia, polyuria, unexplained weight loss
  • Fasting plasma glucose of 126 mg/dL on at least
    2 occasions
  • Fasting plasma glucose of lt 126 mg/dL, but a 75g
    2 hr oral glucose tolerance test plasma glucose
    of 200 mg/dL

7
Diabetes Classification
  • Terms insulin-dependent diabetes and
    non-insulin-dependent diabetes and their
    acronyms (IDDM, NIDDM) were eliminated since
    based on pharmacologic rather than etiologic
    considerations
  • Diabetes subdivided into major groups
  • Type 1 diabetes
  • Type 2 diabetes
  • Other specific types
  • Gestational diabetes mellitus (GDM)

8
Type 1 Diabetes
  • Formerly IDDM or juvenile-onset diabetes
  • Deficiency of endogenous insulin secretion
    secondary to destruction of the insulin producing
    islet beta cells of the pancreas
  • 2 Types
  • Immune mediated Type 1 diabetes
  • 90 occur by an autoimmune process
    (immune-mediated destruction)
  • Characterized by autoantibodies
  • Patients prone to other autoimmune disorders i.e.
    Graves disease, Hashimotos thyroiditis, Addison,
    vitiligo, pernicious anemia

9
Type 1 Diabetes (cont.)
  • 2 Types (cont.)
  • Idiopathic Type 1 diabetes
  • 10 of cases
  • No autoantibodies present
  • No evidence of pancreatic beta cell autoimmunity
  • Symptoms of polyuria, polydipsia, rapid weight
    loss, ketonuria
  • Prone to ketoacidosis
  • Treatment includes Healthy (eucaloric) diet and
    insulin

10
Type 2 Diabetes
  • Formerly NIDDM
  • Results from insulin resistance, mainly caused by
    visceral obesity, with a defect in compensatory
    insulin secretion
  • Accounts for 90 of Americans with diabetes
  • Strong genetic predisposition
  • Most are older than 40 yrs and obese (80-90)
    when diagnosed
  • Frequently undiagnosed for years because
    hyperglycemia develops slowly and symptoms are
    not severe enough to warrant attention

11
Type 2 Diabetes (cont.)
  • Increased risk for microvascular and
    macrovascular complications
  • Hypertension, dyslipidemia, atherosclerosis
  • Symptoms of polyuria, polydipsia
  • Ketonuria and weight loss uncommon at diagnosis
  • Candidal vaginitis may be initial manifestation
    in women
  • Treatment includes
  • Non obese Healthy (eucaloric) diet or diet plus
    oral agent or insulin
  • Obese Weight reduction or hypocaloric diet,
    plus oral agent or insulin

12
Other Specific Types of Diabetes
  • Genetic defects of beta cell function
  • Maturity onset diabetes of the young (MODY),
    Mitochondrial DNA mutations
  • Genetic defects in insulin action
  • Diseases of the exocrine pancreas
  • Pancreatitis, Trauma/pancreatopathy, Neoplasia,
    Cystic fibrosis, Hemochromatosis
  • Endocrinopathies
  • Acromegaly, Cushings, Glucagonoma,
    Pheochromocytoma, Hyperthyroidism,
    Somatostatinoma, Aldosteronoma

13
Other Specific Types of Diabetes (cont.)
  • Drug or chemical-induced
  • Vacor, Pentamidine, Nicotinic Acid,
    Glucocorticoids, Thyroid hormone, Diazoxide,
    ß-Adrenergic agonists, Thiazides, Dilantin,
    a-Interferon
  • Infections
  • Congenital rubella, Cytomegalovirus
  • Uncommon forms of immune-mediated
  • Other genetic syndromes associated with diabetes
  • Down, Klinefelter, Turner, Wolfram, Friedreich
    ataxia, Huntington chorea, Laurence-Moon-Biedl,
    Mytonic dystrophy, Porphyria, Prader-Willi

14
Gestational Diabetes Mellitus (GDM)
  • Any degree of glucose intolerance with onset or
    first recognition during pregnancy
  • Complicates 4 of all pregnancies in the United
    States
  • More common among African American,
    Hispanic/Latino Americans, American Indians
  • More common among obese women and women with a
    family history of diabetes
  • In 30-50, Type 2 diabetes will develop within 10
    yrs of initial diagnosis

15
Manifestations of Diabetes Mellitus
  • Acute manifestations Polydipsia, polyuria,
    polyphagia, weight loss, diabetic ketoacidosis
    (Type 1), hyperosmolar coma (Type 2)
  • Insulin deficiency or resistance results
  • Decreased glucose uptake (hyperglycemia,
    glycosuria, osmotic diuresis, electrolyte
    depletion)
  • Increased protein catabolism (increased plasma
    amino acids, nitrogen loss in urine)
  • Increased lipolysis (increased plasma FFAs,
    ketogenesis, ketonuria, ketonemia)
  • Leads to dehydration, acidosis
  • Results in coma, death

16
Manifestations of Diabetes Mellitus (cont.)
  • Chronic manifestations Nonenzymatic
    glycosylation
  • Small vessel disease (diffuse thickening of
    basement membranes)
  • Retinopathy
  • Nephropathy (nodular sclerosis, proteinuria,
    chronic renal failure, arteriosclerosis leading
    to HTN)
  • Large vessel disease
  • Large vessel atherosclerosis
  • Coronary artery disease
  • Peripheral vascular occlusive disease and
    gangrene
  • Cerebrovascular disease
  • Neuropathy (motor, sensory, autonomic
    degeneration)
  • Cataracts, Glaucoma

17
Diabetic Retinopathy Epidemiology
  • Frequent cause of blindness in the United States
  • Leading cause of blindness in patients 20-64 yrs
  • Prevalence of all types of retinopathy increases
    with duration of diabetes and patient age
  • Rare to find DR in children lt 10 yrs, regardless
    of duration
  • Risk of developing DR increases after puberty

18
Epidemiology
  • Wisconsin Epidemiologic Study of Diabetic
    Retinopathy
  • Between 1979-1980
  • 1210 patients with Type 1
  • 1780 patients with Type 2 predominantly white
    population
  • After 20 yrs of diabetes, 99 of Type 1 and 60
    of Type 2 diabetics had some degree for DR
  • 3.6 of Type 1 and 1.6 of Type 2 diabetics were
    legally blind
  • 86 of Type 1 blindness attributable to DR
  • 1/3 of Type 2 blindness attributable to DR

19
Diabetic Retinopathy (DR)
  • Advanced Diabetic Retinopathy is associated with
    cardiovascular disease risk factors, i.e.
  • Family history of CVD
  • Increased age
  • Hypertension
  • Tobacco use
  • Physical inactivity
  • Stress
  • Dyslipidemia
  • Patients with Proliferative Diabetic Retinopathy
    (PDR) are at increased risk of heart attack,
    stroke, diabetic nephropathy, amputation, death

20
Pathogenesis of Diabetic Retinopathy
  • Exact cause of diabetic microvascular disease is
    unknown
  • Prolonged exposure to hyperglycemia results in
    biochemical and physiologic changes that
    ultimately cause vascular endothelial damage
  • Hyperglycemia and hypertension from diabetes can
    affect
  • Retina (retinopathy)
  • Retinal vasculature (increased incidence of other
    retinal vaso-occlusive phenomenon, i.e. CRVO)
  • Vitreous (vitreous hemorrhage, fibrosis)
  • Lens (accelerated cataract formation)
  • Optic Nerve (chronic and acute vaso-occlusive
    disease can lead to rubeosis and glaucoma
  • Cranial Nerves (cranial mononeuropathies)

21
  • Retina
  • Innermost lining of the eye
  • Consists of the sensory retina composed of
    light-sensitive neural elements connecting to
    other neural cells, and the retinal pigment
    epithelium
  • Vitreous
  • Transparent, colorless mass of soft, gelatinous
    material filling the eye behind the lens
  • Lens
  • Transparent, biconvex structure suspended in the
    eye between the aqueous and the vitreous
  • Functions to bring rays of light to focus on the
    retina and in accommodation
  • Optic Nerve
  • Nerve that carries visual impulses from the
    retina to the brain

22
Pathogenesis (cont.)
  • Normal retinal circulation is unique
  • Retinal capillaries are non-fenestrated and
    capillary endothelial cells have tight junctions
    normal retinal capillaries do not leak fluid,
    blood
  • No lymphatic system in the retina
  • In the presence of retinal pathology, leaking
    fluid can accumulate and cause edema or swelling
  • Retina responds to ischemia by stimulating growth
    factors to produce new vessels (called
    neovascularization)

23
Pathogenesis (cont.)
  • Specific retinal vascular changes include
  • Loss of pericytes (cells that control vessel
    flow)
  • Basement membrane thickening, which compromises
    the capillary lumen (affecting the blood supply
    to the eye)
  • Decompensation of the endothelial barrier
    function of retinal vessels

24
Pathogenesis (cont.)
  • Thus, 2 key changes occur
  • Vessel permeability
  • Damaged endothelial wall becomes more porous
  • Vessel leaks fluid, lipids, erythrocytes
  • Accumulation of the fluid results in edema
    (macular edema if located within the central
    region of the retina)
  • Vessel closure
  • Supply of oxygen and nutrients are decreased
  • New fragile growth occurs (secondary to ischemia)

25
Pathogenesis (cont.)
  • Diabetic Retinopathy is a progressive disease
    that destroys retinal capillaries by depositing
    abnormal material along the walls of blood
    vessels in the retina
  • Causes vessel permeability and closure retinal
    blood vessels
  • Resulting vessel leakage of fluid, lipid, and
    blood and in ischemia (decreased oxygen and
    nutrients to retina) and growth in new abnormal
    retinal blood vessels

26
Classification of Diabetic Retinopathy
  • Classified into 2 stages
  • Nonproliferative Diabetic Retinopathy (NPDR)
  • Early stage
  • Also known as Background DR (BDR)
  • Further categorized based upon extent of DR
  • Minimal, Mild, Moderate, Severe, Very severe
  • Proliferative Diabetic Retinopathy (PDR)
  • More advance stage
  • Further described as Early, High-risk, Advanced
  • Macular edema
  • May be present at any level of DR

27
NPDR
  • Typically asymptomatic, but may have decreased or
    fluctuating vision with fluctuation in blood
    sugars
  • NPDR can affect visual function through 2
    mechanisms, both which affect the macula
  • Variable degrees of intraretinal capillary
    closure resulting in macular ischemia
  • Increased retinal vascular permeability resulting
    in macular edema

28
NPDR
  • Characterized by
  • Microaneurysms
  • Dot-blot hemorrhages
  • Flame-shaped hemorrhages
  • Retinal edema
  • Hard exudates
  • Venous dilation beading
  • Intraretinal microvascular abnormalities (IRMA)
  • Nerve fiber layer infarcts (cotton wool spots)
  • Arteriolar abnormalities
  • Areas of capillary nonperfusion

29
NPDR
  • NPDR is diagnosed by dilated fundoscopic
    examination with use of the slit lamp, lenses,
    and binocular indirect ophthalmoscope

30
Minimal NPDR
  • At least 1 Microaneurysms (m)
  • Microaneurysms only
  • Remainder of fundus normal

31
Mild NPDR
  • Microaneurysms (m) and Dot hemorrhages (h)
  • May also demonstrate macular edema and lipid
    exudate (e)

32
Moderate NPDR
  • Cotton wool spots (w), Retinal hemorrhages (h)
    (Dot-blot, Flame), and Microaneurysms (m)
  • Hemorrhages, Microaneurysms in at least 1
    quadrant, and cotton wool spots or venous beading
    in 1 quadrant only
  • Less than Severe

33
Progression from NPDR to PDR
  • Severe NPDR was defined by the Early Treatment of
    Diabetic Retinopathy Study (ETDRS)
  • ETDRS devised the 421 rule to predict the
    progression of NPDR to PDR
  • 421 rule is characterized by any one of the
    following
  • Diffuse intraretinal hemorrhages and
    microaneurysms in 4 quadrants
  • Venous beading in 2 quadrants
  • Intraretinal microvascular abnormalities (IRMA)
    in 1 quadrant

34
Severe NPDR
  • Hemorrhages (h) or Microaneurysms (m) in all 4
    quadrants
  • Venous beading (b) in 2 or more quadrants
  • IRMA (i) in 1 or more quadrants

35
Progression from NPDR to PDR
  • ETDRS found that Severe NPDR had a 15 chance of
    progression to High-risk PDR within 1 yr
  • ETDRS also defined Very severe NPDR as the
    presence of any two of the 421 features
  • Very severe NPDR had a 45 chance of progression
    to High-risk PDR within 1 yr
  • ETDRS indicated that Pre-proliferative diabetic
    retinopathy includes nerve fiber layer infarcts
    (cotton wool spots or soft exudates)

36
Progressive NPDR
  • Retinal capillary nonperfusion is a feature
    commonly associated with progressive NPDR
  • Fluorescein angiography can show the extent of
    diabetic ischemia and capillary nonperfusion

37
PDR
  • More likely to become symptomatic than early NPDR
  • May have decreased vision, sudden vision loss,
    floaters, cobwebs, flashes, dull eye ache
  • PDR can also affect visual function by affecting
    the macula with resulting macular ischemia and/or
    edema

38
PDR
  • Severe, advanced stage of DR in which new
    abnormal blood vessels proliferate on the retinal
    surface
  • Neovascularization of the disc (NVD)
  • Neovascularization elsewhere (NVE)

39
PDR
  • PDR is diagnosed primarily by dilated fundoscopic
    examination, with use of the slit lamp, lenses,
    binocular indirect ophthalmoscope and sometimes
    by fluorescein angiography (FA)
  • FA shows leakage at the disc, indicating abnormal
    new blood vessel growth of the disc (NVD)

40
PDR
  • Characterized by
  • Peripheral new vessels (v), neovascularization
    elsewhere (NVE)
  • Disc new vessels, neovascularization of disc
    (NVD) lt 1/3 disc area (Not shown)
  • Vitreous or preretinal hemorrhage with NVE lt ½
    disc area (Not shown)
  • Retinal hemorrhage (h)

41
PDR
42
PDR
  • PDR is present in varying stages
  • Initial appearance of new vessels with minimal
    fibrosis
  • Increase in size and extent of new vessels with
    increased fibrous component
  • Regression of new vessels with residual
    fibrovascular proliferation along vitreous

43
High-risk PDR
  • Diabetic Retinopathy Study (DRS) defined
    High-risk PDR as any one of the following
  • Mild neovascularization of the disc (NVD) with
    vitreous hemorrhage
  • Moderate to severe NVD with or without vitreous
    hemorrhage (showing gt ¼ to 1/3 disc area of NVD)
  • Moderate (½ disc area) NVE with vitreous
    hemorrhage
  • DRS defined High-risk PDR so as to recommend
    prompt treatment to these patients with the
    highest risk of severe vision loss (treatment
    with panretinal photocoagulation)

44
High-risk PDR
  • Large frond of NVD (v)
  • Pre-retinal hemorrhage (h)
  • Cotton wool spots
  • Intraretinal hemorrhage
  • Venous beeding

45
Advanced PDR
  • Complications may be exacerbated by tractions of
    the vitreous on elevated fibrovascular
    proliferative tissue
  • Partial posterior vitreous detachments frequently
    develop in eyes with fibrovascular proliferation
  • Resulting in traction on the new vessels and
    vitreous causing preretinal hemorrhage
    (hemorrhage above the retina and/or within the
    vitreous)
  • Vitreous hemorrhage may not resolve, especially
    if there is an excessive fibrovascular component

46
Advanced PDR (cont.)
  • Additional tractional complications include
    tractional retinal detachment, progressive
    fibrovascular proliferation
  • Chronic retinal detachment or chronic retinal
    ischemia in eyes with PDR can increase the risk
    for development of iris neovascularization (NVI,
    rubeosis) and neovascular glaucoma (NVG)

47
Advanced PDR
  • Fibrovascular proliferative (f) from old NVE and
    old NVD
  • Preretinal and intraretinal hemorrhages

48
Advanced PDR
  • Vitreous hemorrhage from NVE or NVD

49
Advanced PDR
  • Tractional retinal detachment resulting from
    contraction of the fibrovascular proliferative
    tissue on the retina

50
NPDR and PDR
51
Diabetic Macular Edema (DME)
  • Retinal edema threatening or involving the macula
    is an important visual consequence of abnormal
    retinal vascular permeability in DR
  • Diagnosis is made by slit-lamp biomicroscopy of
    the retina using a contact lens
  • Important observations include
  • Location of retinal thickening relative to the
    fovea
  • Presence and location of exudates
  • Presence of cystoid macular edema
  • Fluorescein angiography is useful in
    demonstrating the breakdown of the blood-retinal
    barrier by delineating retinal capillary leakage
    and capillary nonperfusion

52
Diabetic Macular Edema (DME)
  • DME may manifest as focal or diffuse thickening
    with or without exudates
  • 2 general categories of DME described
  • Focal macular edema
  • Characterized by areas of focal fluorescein
    leakage from specific capillary lesions
  • May be associated with white to yellow lipid
    deposits, called hard exudates
  • Diffuse macular edema
  • Characterized by widespread retinal capillary
    abnormalities with diffuse leakage from extensive
    breakdown of blood-retinal barrier
  • Often associated with cystoid macular edema

53
DME and CSME
  • Early Treatment Diabetic Retinopathy Study
    (ETDRS) also defined clinically significant
    macular edema (CSME) as any one of the following
  • Retinal edema located at or within 500 µm of the
    center of the macula
  • Hard exudates at or within 500 µm of the center
    if associated with thickening of adjacent retina
  • Zone of thickening larger than 1 disc area if
    located within 1 disc diameter of the center of
    the macula
  • ETDRS demonstrated that eyes with CSME benefited
    from treatment with focal Argon laser

54
CSME
  • CSME diagnosed primarily at the slit lamp (to
    assess retinal thickening)
  • Hard exudates located within the center of the
    macula likely

55
Effect of Systemic Conditions on Diabetic
Retinopathy
  • Elevated serum lipids are associated with
    presence and severity of retinal hard exudates in
    NPDR and DME
  • Hypertension is usually associated with a higher
    risk of progression of DME and DR
  • Asymmetric carotid artery occlusive disease
    worsens ocular ischemia and DR on the affected
    side
  • Severe carotid artery occlusive disease may
    result in advanced PDR
  • Advanced diabetic nephropathy and anemia may also
    have adverse influences on DR

56
Effect of Systemic Conditions on Diabetic
Retinopathy (cont.)
  • Pregnancy is associated with worsening of DR
  • Pregnant women require more frequent retinal
    evaluation
  • All patients will have some regression of DR
    after delivery
  • Although teratogenic effects of fluorescein have
    not been identified, FA is avoided in pregnant
    and breastfeeding women unless absolutely
    necessary
  • Fluorescein crosses the placenta and will be
    transmitted to breast milk
  • Photocoagulation treatment is generally recommend
    if High-risk PDR develops during pregnancy

57
Management of Diabetes
  • Requires ongoing medical care with a general
    practitioner or endocrinologist, and
    ophthalmologist or optometrist
  • Annual evaluation of proteinuria, microalbinuria
  • Eye exam (as indicated by eye doctor)
  • Routine HbA1C
  • Prevention of acute-illness and complications
  • Patient and family education
  • Wear necklace or bracelet
  • Daily self-exam of feet
  • Self blood glucose and blood pressure monitoring
  • Increase physical activity
  • Encourage patients to take an active role in
    their health care (empowerment)

58
Management of Diabetes
  • Follow healthy diet that has been evaluated by
    physician and/or nutritionist/dietician
  • Eucaloric if nonobese
  • Hypocaloric if obese
  • Control of plasma glucose via diet and/or oral
    hypoglycemics and/or insulin
  • Control of blood pressure and plasma lipid
  • Tobacco cessation
  • ACE inhibition
  • Protective effect on kidneys
  • Baby ASA if not otherwise contraindicated

59
Diabetic Control and Diabetic Retinopathy
  • Diabetes Control and Complications Trial (DCCT)
  • Evaluated effect of intensive blood glucose
    control on subsequent progression of DR in Type 1
    diabetics without DR and with Mild-Moderate NPDR
  • Study Groups Intensive control of blood sugar
    (multiple daily insulin injections or insulin
    pump) vs. Conventional management
  • Results Intensive control reduced the risk of
    developing DR by 76 and slowed progression of DR
    by 54
  • In patients with Mild-Moderate NPDR, DR worsened
    with intensive control during the first year
  • Intensive control also reduced risk of clinical
    neuropathy by 60 and albuminuria by 54

60
Diabetic Control and Diabetic Retinopathy
  • United Kingdom Prospective Diabetes Study (UKPDS)
  • From 1977 to 1991
  • Evaluated effect of intensive blood glucose and
    blood pressure control on subsequent progression
    of DR in Type 2 diabetics
  • Study Groups
  • Intensive control of blood sugar (oral agent or
    insulin) vs. Conventional management (diet)
  • Tight control of blood pressure (ACE inhibitor
    and/or Beta-blocker) or less tight control
  • Results Intensive control of blood glucose and
    blood pressure slowed progression of DR and
    reduced risk of other microvascular (and
    macrovascular with tight BP control)
    complications

61
Management of Diabetic Retinopathy
  • Diabetic Screening
  • Type 1 diabetics Dilated funduscopic exam (DFE)
    5 yrs after diagnosis
  • Newly diagnosed patients with Type 1 diabetes
    rarely have retinopathy during the first 5 yrs
  • Type 2 diabetics DFE at the time of diagnosis
  • DR typically seen within 10 yrs of onset
  • Type 2 diabetics typically diagnosed yrs after
    initial onset
  • Significant portion of newly diagnosed Type 2
    diabetics have established DR at the time of
    diagnosis

62
Management of Diabetic Retinopathy
  • Diabetic Follow-up
  • Pregnant women DFE is recommended in the 1st
    trimester and thereafter at the discretion of the
    ophthalmologist
  • Pregnant women are at high risk of progression of
    DR during pregnancy
  • Depending upon the severity of DR and the threat
    to visual function from progression, suggested
    follow-up for patients with NPDR, PDR, and DME
    may differ

63
Follow-Up Based Upon Retinopathy Findings
64
Treatment of Diabetic Retinopathy
  • Based on findings of the Diabetic Retinopathy
    Study (DRS), Early Treatment Diabetic
    Retinopathy Study (ETDRS), and other studies,
    laser photocoagulation is generally recommended
    for eyes with
  • Clinically significant macular edema (CSME)
  • ETDRS found focal Argon laser photocoagulation
    decreased risk of moderate visual loss and
    reduced retinal thickening
  • High-risk Proliferative DR (PDR)
  • DRS found Argon or Xenon laser panretinal
    photocoagulation (scatter PRP) reduced risk of
    severe vision loss compared to no treatment
  • Treated eyes with High-risk PDR achieved the
    greatest benefit

65
Treatment of Diabetic Retinopathy
  • ETDRS reported that provided follow-up can be
    maintained, scatter PRP was not recommended for
    patients with Mild or Moderate NPDR
  • Scatter PRP can be considered when NPDR becomes
    Severe or Preproliferative NPDR and should not be
    delayed when reaches High-risk PDR
  • Scatter treatment for eyes with Severe NPDR or
    Early PDR is effective in reducing severe vision
    loss in Type 2 diabetics

66
Focal Photocoagulation for CSME
  • Fluorescein angiography and Fundus photos are
    obtained prior to initiation of laser therapy
  • Ophthalmologist views the FA to guide treatment
    of CSME
  • For focal leakage, direct laser therapy using
    green-only Argon laser is applied to all leaking
    microaneurysms between 500 and 3000 µm from the
    center of the macula
  • For diffuse leakage or zones of capillary
    nonperfusion adjacent to the macula, a
    light-intensity grid pattern using green-only
    Argon laser is applied to all areas of diffuse
    leakage more than 500 µm from the center of the
    macula and 500 µm from the temporal margin of
    the optic disc
  • Multiple sessions spread out over many months are
    frequently necessary for resolution of DME

67
Focal Photocoagulation for CSME
  • Side Effects and Complications of Focal Laser
  • Paracentral scotomata
  • Transient increased edema/decreased vision
  • Choroidal neovascularization (new abnormal blood
    vessel growth beneath the retina)
  • Subretinal fibrosis
  • Photocoagulation scar expansion
  • Inadvertent foveolar burns

68
Panretinal Photocoagulation for High-risk PDR
  • Scatter PRP almost always recommended for
    High-risk PDR
  • Should be avoided in areas of prominent
    fibrovascular membranes, vitreoretinal traction,
    and tractional retinal detachment

69
Panretinal Photocoagulation for High-risk PDR
  • Goal is to cause regression of existing
    neovascular tissue and to prevent progressive NV
    in the future
  • Amount of therapy necessary to achieve these
    endpoints is determined by clinical response to
    treatment
  • Full PRP includes 1200 or more 500 µm burns
  • Treatment may be devided into 2 or more sessions

70
High-risk PDR Pre- and Post-PRP
71
PRP for High-risk PDR
  • Side Effects and Complications of Scatter PRP
  • Decrease in night vision, color vision, and/or
    peripheral vision as well as a loss of 1 or 2
    lines in visual acuity in some
  • Glare
  • Temporary loss of accommodation
  • Photopsia (flashes)
  • Worsening of macular edema, if present prior to
    treatment

72
Cataract Surgery in Diabetics
  • Various studies suggest that DR may progress
    following cataract surgery
  • Patients who undergo cataract surgery with CSME,
    Severe NPDR, or PDR should be considered for
    photocoagulation prior to cataract removal
  • If density of cataract precludes adequate
    evaluation of the retina or precludes treatment,
    prompt post-operative retinal evaluation and
    treatment can be considered

73
Neovascularization of the Iris (NVI)
  • Neovascularization in PDR may manifest as NVD,
    NVE, or NVI (neovascularization of the iris,
    rubeosis)
  • NVI involving the anterior chamber angle (NVA)
    may lead to increased intraocular pressure,
    neovascular glaucoma (NVG) and resulting optic
    nerve damage
  • Patients with extensive neovascularization of the
    iris or involving the anterior chamber angle
    require panretinal photocoagulation whether or
    not High-risk PDR is present
  • To cause regression of existing neovascular
    tissue and to prevent progressive
    neovascularization in the future

74
Surgical Treatment of PDR
  • Surgical Vitrectomy (removal of the vitreous gel)
    is indicated in the following diabetic patients
  • Dense, nonclearing vitreous hemorrhage
  • Tractional retinal detachment involving the
    macula
  • Combined tractional and rhegmatogenous retinal
    detachment
  • Presence of dense, nonclearing vitreous
    hemorrhage requires echography (use of
    B-scan/Ultrasound) to evaluate the presence or
    absence of retinal detachment
  • If retinal detachment present, early vitrectomy
    suggested
  • Patients with bilateral severe vitreous
    hemorrhage should undergo vitrectomy in one eye

75
Prevention of Diabetic Retinopathy
  • Prevention of diabetic retinopathy requires
    prevention of diabetes
  • Patients at higher risk (i.e. family history,
    ethnicity) of developing diabetes can adjust
    modifiable risk factors
  • Healthy diet
  • Exercise
  • Blood pressure control
  • Tobacco cession
  • Weight reduction (if obese)

76
Prevention of Diabetic Retinopathy
  • Tight blood sugar and blood pressure control
  • Tight control slows the progression of diabetic
    retinopathy
  • Annual dilated fundoscopic examinations (DFE) by
    an ophthalmologist and/or optometrist
  • To evaluate for retinopathy, cataracts, and
    glaucoma
  • More frequent follow-up with an ophthalmologist
    depending upon extent of retinopathy
  • Pregnant women with DR or GDM should have a DFE
    during the first 3 months
  • More frequently depending upon diagnosis of
    retinopathy
  • Tobacco cessation
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