Diabetic Retinopathy Me
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Transcript of Diabetic Retinopathy Me
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Diabetic Retinopathy
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Diabetic Retinopathy
It is an eye condition that affectspeople with diabetes (uncontrolledfor a prolonged period of time).
It is usually bilateral.
It is the result of damage caused by
diabetes to the small blood vesselslocated in the retina.
P.S. Too much blood sugar can destroy
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How does diabetes causeDR?
Causes abnormal changes in theblood sugar (glucose) that your bodyordinarily converts into energy to fuel
different bodily functions
Uncontrolled diabetes, allowsunusually high levels of blood sugar
(hyperglycemia) to accumulate inblood vessels, causing damage thathampers or alters blood flow to your
bodys organs - including the EYE.
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2 classifications:
Type 1 patients who are insulindependent because youll needinjections or other medications to
supply the insulin.
Type 2 patients who produceenough insulin but your body is
unable to make proper use of it. thebody compensates for it byproducing even more insulin.
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Eye damage occurswhen:
Chronically high amounts of bloodsugar begin to clog or damage bloodvessels within the eyes retina, which
contains light-sensitive cells(photoreceptors) necessary for goodvision.
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Prevalence
Data from the NNS showed that theprevalence of diabetesmellitus (DM) increases with age.
Among young adults 20-29 years old,DM prevalence is as low as 0.4percent, increasing at 3.2 percentamong adults 30-39 years old. This
nearly doubles at 5.7 percent amongthe 40-49 years old, then to 9.0percent among 50-59 years old. DM
prevalence is highest among older-
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Symptoms of DR:
Fluctuating vision
Floaters
Development of a scotomas orshadow in your field of view
Exudates
Blurry and distorted vision
Corneal abrasions resulting toabnormalities
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Assessment pearls:
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Measure :
Visual acuity
LogMAR charts
Used to assess an individual'svisual acuity (VA).
LogMAR means the logarithmof the Minimum Angle of
Resolution.This has led to the assertion
that researches done using alogarithmic progression insize of letters on test chart
gives most accurate VAmeasurement.
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2. Grading of DR:
Modified Airlie house classification
(Wisconsin system) Basis for detailed grading of DR and was used
in all major studies of risk factors and trials oflaser and other treatments.
Based on grading seven 30 degreesstereoscopic fields
Optic disc
Macula Lateral macula
Upper temporal arcades
Lower temporal arcades
Upper nasal arcades
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3. Examinations, Sensitivity and Specificityin Detecting Diabetic Retinopathy
Stereoscopic 7 field fundus photography
It is the gold standard method of detectingDiabetic Retinopathy.
Slit lamp Biomicroscopy (routine practice) =
90D or 78D after pupil dilation. Ophthalmoscopy (direct or indirect)
retinal photography
4. New modalities to assess the severity ofdiabetic retinopathy
Slit lamp Biomicroscopy
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Optical Coherence Tomography
Provides an effective qualitative and quantitativemethod of examining the eye, in particularscreening for early macular thickening and alsofollowing progression or regression of macularedema over the course of treatment.
Has good reproducibility and accuracy for themeasurement of retinal thickness with an axialresolution n the order of 10um.
Also correlates reasonably with both Biomicroscopicexamination and FA in CSME.
Heidelberg Retinal Tomography
Detects DME by using scanning laser
ophthalmoscopy to provide an indirect measure of
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Retinal Thickness Analyzer
Projects oblique laser slits onto the posterior pole todetermine retinal thickness.
Electoretinogram(ERG)
Non-invasive objective method of evaluating retinal
function by measuring the bioelectrical response ofthe retina to visual stimuli.
Colour contrast threshold testing
Testing of tritan wavelengths as a useful method ofidentifying sight-threatening DR particularly whencombined with retinal photography.
Computerized diabetic retinopathy grading
system
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Other factors
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q Smoking - Smoking is also proven tobe a risk factor for insulin resistance.
Patients who are insulin resistantcannot use their bodily insulinproperly. Smoking is now proven to
be an independent risk factor fordiabetes, and amongst diabetics itincreases the risk of complications.
q
Pregnancy - Pregnancy may cause arapid increase in the progression ofdiabetic retinopathy. That is, if awoman has mild retinopathy, it mayprogress into a much more severe
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Classifications of DR
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on-pro era ve(Background)
Retinopathy Early state of the disease in which symptoms will bemild or non-existent.
The blood vessels are weakened causing tiny bulgescalled MICROANUERYSMS (may leak fluid which may
lead to swelling of the macula).
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Early ProliferativeRetinopathy
The blood vessels on the surface ofthe optic disc and nearby retina forma tangle instead of an orderly
branching. Arising under chronic retinal
ischemia, these new blood vessels
are weak-walled and bleed easily intothe retina or vitreous cavity
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Advanced ProliferativeRetinopathy
More advanced form.
New fragile blood vessels can begin to grow in theretina and into the vitreous due to the circulationproblem causing oxygen deprivation of the retina.
The new blood vessels may leak blood into thevitreous, causing clouding of vision.
Retinal detachment (scar tissue formation anddevelopment of glaucoma)
a e c
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a e cMacular
Edema (DME) Capillary leak in the macular or perimacular region Thickening located within two disc diameters of the
centre of the macula.
When this is present within or close to the centralmacula, it is termed clinically significant macularedema (CSME)
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Complications:
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Vitreous Hemorrhage
hemorrhage from fragile blood vessels leaking intothe vitreous, the clear gel-like substance that fillsthe interior of the eye. If blood clouds the vitreous,light passing from the lens through the vitreous tothe retina is blocked, and vision is markedly
reduced. Cataract
Diabetes increases the possibility of cataract, a
clouding of the transparent lens of the eye.Cataract may cause hazy vision and glaresensitivity. If retinopathy has not damaged theretina, surgical removal of a cataract usuallyresults in improved vision. If there is damage tothe retina, the cataract may still be removed in
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Secondary Glaucoma
Fragile new blood vessels in the eye of someonewith diabetes may form a new network directly onthe iris, blocking the outflow of fluid from the eye.
This condition, called secondary glaucoma, resultsin elevated pressure of the fluids within the eye,
and can cause optic nerve atrophy and loss of thefull visual field. Treatment involves the applicationof laser to the leaking areas. Standard glaucomatreatment with drops or diuretics may also be
recommended to lower intraocular pressure. Macular Damage
In chronic macular edema, faulty color vision mayresult and usually is irreversible. Even after themacula has been treated with laser, there may still
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Treatment Options
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Background Retinopathy
Requires no treatment, butregular eye examinations areessential as it may progress.
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Proliferative Retinopathy
Scatter or Pan-retinal photocoagulation
Performed using 200 to 500 um burnsplaced approximately one half burn width
apart, from the posterior fundus to theequator.
Used to slow down the growth of newabnormal blood vessels that have
developed over a wide area of the retina. Vitrectomety done when: there is bleeding
into the eye from abnormal blood vessels,proliferative retinopathy has been identified
at a late stage, laser treatment has been
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Maculopathy
Laser treatment = firing laser at the area ofleakage to seal off the leaking and prevent itfrom progressing. Will burn the retina but insmall quantities that the eye can recover from.
Intravitreal anti-VEGF injections (anti-vascularendothelial growth factor) such as lucentis orAvastin.
Avastin is an injection into the eye. It is one of
the anti-VEGF drugs. These may need to begiven monthly, as in the Restore study see.(Lucentis is similar to Avastin, but a lot moreexpensive.). The injections may need to becontinued long term to maintain sight.
Intravitreal steroids = which is rarely used