2. Diabetes Mellitus
● Diabetes is a major concern for healthcare systems
throughout the world.
● Approximately one-half of individuals with
diabetes will develop retinopathy in time
3. Definition Epidemiology
Diagnosis Treatment
01 02
Describe the risk factors and
prevalence
04
Describe the tests to be done
and signs seen on
examination
05
Enumerate the management
options and guidelines
Objectives
Describe what is Diabetic
Retinopathy
03
Describe the disease
progression and how it forms
06
Outline the schedule for
follow-ups for tertiary
prevention
Pathology
Prevention
5. Definition - Diabetic Retinopathy
● Disorder of the retina due to the vascular changes brought
about by diabetes
● A microangiopathy wherein small blood vessels (especially
in the retinas) are particularly vulnerable to damage from
high glucose levels
● It ranges from non-proliferative diabetic retinopathy
(NPDR) and its stages to proliferative diabetic retinopathy
(PDR).
7. Prevalence
● Estimated to be around 40%
● It is more common in type 1 diabetes than in type
● About 5% of type 2 diabetics have DR at presentation
● Sight-threatening disease is present in up to 10%
● Proliferative diabetic retinopathy (PDR) affects 5–10% of
the diabetic population
8. Risk factors
● Duration of diabetes
● Poor control of diabetes
○ By decreasing the HbA1c by 1% the microvascular
complications can be reduced by one-third.
● Pregnancy
● Hypertension
● Nephropathy
● Hyperlipidaemia, smoking, cataract surgery, obesity and
anaemia
10. Pathology
2 types of Diabetic Retinopathy (DR)
● Non-proliferative DR (NPDR)
● Proliferative DR (PDR)
The difference of which lies on the presence or absence of
abnormal new blood vessels (retinal, optic disc, or iris/angle
neovascularization).
11. Pathogenesis
Exact mechanism is unknown
High glucose levels
-> Microcapillary damage
-> Loss of pericytes and BM thickening
-> Capillary occlusion and retinal nonperfusion
-> VEGF release
-> Decompensation of
endothelial barrier fx
-> Serum leakage and
retinal edema
Vitreous
hemorrhage
13. Diagnosis / Diagnostic procedures
Symptoms:
Decreased vision or fluctuating vision, presence of
floaters or visual field defects
- Slit Lamp Examination
- Dilated Fundus Examination
- Fluorescein Angiography (FA)
- Optical Coherence Tomography (OCT)
- HbA1c
14.
15. Classifications (ETDRS)
1. Background Diabetic Retinopathy
- Presents as
- Microaneurysms
- Dot and blot hemorrhage
- Exudates
The earliest signs of DR
16. 2. Diabetic Maculopathy
- Strictly refers to the presence
of any retinopathy at the
macula
- Particularly vision-threatening
edema and ischaemia
18. 4. Proliferative Diabetic Retinopathy
Characterized by:
- neovascularization on or within one disc
diameter of the disc (NVD)
- and/or new vessels elsewhere (NVE) in
the fundus
20. Classifications for NPDR
Mild: few microaneurysms
Moderate: increased number of microaneurysms and dot-blot
hemorrhages. Cotton wool spots and hard exudates may be
present.
Severe: "4-2-1 rule" -> 4 quadrants of diffuse retinal
hemorrhages and microaneurysms, 2 or more quadrants of
venous beading, or 1 or more quadrant of IRMA
- Usually no treatment
- Anti-VEGF has been shown decrease the severity of
retinopathy and lower the risk of vision complications.
21. PDR High-risk Characteristics
- NVD >1/4 TO 1/3 of disc area
- Any NVD associated with vitreous or preretinal
hemorrhage
- Any NVE associated with vitreous or preretinal
hemorrhage
This is progressive and requires treatment to prevent bleeding
and scar tissue formation.
25. Treatment / Prevention
General
- Patient education (ABCDE’s) of DR Prevention
- Fenofibrate 200mg daily
- Has been shown to reduce the progression of DR in
type 2 diabetes
- Correct anemia and renal failure
26. Treatment
For Diabetic Macular Edema
- Anti-VEGF therapy (Intraocular Injection)
- Bevacizumab
- Ranibizumab
- Laser treatment should be deferred for 6 months
after commencement of anti-VEGF therapy
- Laser photocoagulation
- Has been replaced by Anti-VEGF Therapy as the
mainstay, though it remains a well-proven therapeutic
option
- Should still be considered in cases with off-center
swelling when exudates threaten the fovea
28. Treatment
For Advanced Diabetic Eye Disease
- Pars Plana Vitrectomy (PPV)
- Remove non-clearing vitreous
- Indicated when:
- Severe persistent vitreous haemorrhage
- Progressive tractional RD - Macula is threatened
- Combined tractional and rhegmatogenous RD
- Premacular retrohyaloid haemorrhage
- Anterior segment neovascularization and media
opacities
29. Prevention / Eye Examination Schedule
Diabetes Type First Eye Exam
Routine Minimum
Follow-up Interval
Type 1
3-5 years after
diagnosis
Annually
Type 2 Upon diagnosis Annually
Type 1 or 2
+ Pregnancy
Before conception or
early in the first
trimester
No retinopathy to
mild/moderate NPDR - Every
3-12 months
Severe NPDR to worse
Every 1-3 months
30. Prevention / Eye Examination Schedule
Severity
Clinically Significant
Macular Edema
Follow-up interval
(in months)
Normal or minimal NPDR No 12 mos
Mild-Moderate NPDR
No
Yes
6-12
2-4
Severe NPDR Either 2-4
Non-high risk PDR Either 2-4
High risk PDR Either 2-4
Inactive/Involuted PDR
No
Yes
6-12
2-4
32. REFERENCES
Feldman, B.H. et al. (2023) Diabetic retinopathy, EyeWiki.
Available at: https://eyewiki.aao.org/Diabetic_Retinopathy
(Accessed: 26 February 2024).
Editor's Notes
Ophthalmic complications of diabetes
} Common
○ Retinopathy: diabetic macular oedema, macular ischaemia and sequelae arising from retinal ischaemia (retinal
new vessels, vitreous haemorrhage and tractional retinal
detachment).
○ Iridopathy (minor iris transillumination defects).
○ Unstable refraction.
} Uncommon
○ Recurrent styes.
○ Xanthelasma.
○ Accelerated age-related cataract.
○ Neovascular glaucoma (NVG).
○ Ocular motor nerve palsies.
○ Reduced corneal sensitivity.
} Rare. Papillopathy, pupillary light-near dissociation,
Wolfram syndrome (progressive optic atrophy and multiple neurological and systemic abnormalities), acute-onset cataract, rhino-orbital mucormycosis.
decreased vision or fluctuating vision (DME), presence of floaters (vitreous hemorrhage), or visual field defects (tractional detachment)
Fluorescein angiography (FA) may be used to determine the degree of ischemia or the presence of retinal vascular abnormalities. The areas of microaneurysms appear as hyperfluorescent spots and may leak on the late frames resulting in areas of retinal edema clinically. The areas of NVD/ NVE also show leakage on the FA. Areas of capillary dropout and non-perfusion will appear hypofluorescent.
Optical coherence tomography (OCT) is useful to determine the presence and location of intraretinal and/or subretinal fluid as well as retinal thickness measurements. The OCT can be sequentially obtained to determine whether the macular edema is responding to therapy.
Early Treatment Diabetic Retinopathy Study (ETDRS – the modified Airlie House classification
Early Treatment Diabetic Retinopathy Study (ETDRS – the modified Airlie House classification
Retinal thickening within 500 μm of the centre of the macula (Fig. 13.10, upper left).
Exudates within 500 μm of the centre of the macula, if associated with retinal thickening. The thickening itself may be outside the 500 μm (Fig. 13.10, upper right). }
Retinal thickening one-disc area (1500 μm) or larger, any part of which is within one disc diameter of the centre of the macula (Fig. 13.10, lower centre).
Indicates progressive retinal ischaemia, with a heightened risk of progression to retinal neovascularization.
New vessels at the disc (NVD) describes neovascularization on or within one disc diameter of the optic nerve head (Fig. 13.14). }
NVE describes neovascularization further away from the disc (Fig. 13.15). It may be associated with fibrosis if long-standing. }
New vessels on the iris (NVI – Fig. 13.16), also known as rubeosis iridis, carry a high likelihood of progression to neovascular glaucoma (see Ch. 11). }
FA (see Fig. 13.14C) highlights neovascularization during the early phases of the angiogram and shows irregular expanding hyperfluorescence during the later stages due to intense leakage
Haemorrhage may be preretinal (retrohyaloid), intragel or both (Fig. 13.22A and B). Intragel haemorrhages usually take longer to clear than preretinal because the former is usually more substantial. In some eyes, altered blood becomes compacted on the posterior vitreous face to form an ‘ochre membrane’. Ultrasonography is used in eyes with dense vitreous haemorrhage to detect the possibility of associated retinal detachment.
Tractional retinal detachment (Fig. 13.22C) is caused by progressive contraction of fibrovascular membranes over areas of vitreoretinal attachment. Posterior vitreous detachment in eyes with PDR is often incomplete due to the strong adhesions between cortical vitreous and areas of fibrovascular proliferation. Haemorrhage often occurs at these sites due to stress exerted on NV
Early Treatment Diabetic Retinopathy Study (ETDRS – the modified Airlie House classification
Early Treatment Diabetic Retinopathy Study (ETDRS – the modified Airlie House classification
Early Treatment Diabetic Retinopathy Study (ETDRS – the modified Airlie House classification
Early Treatment Diabetic Retinopathy Study (ETDRS – the modified Airlie House classification
Early Treatment Diabetic Retinopathy Study (ETDRS – the modified Airlie House classification
Early Treatment Diabetic Retinopathy Study (ETDRS – the modified Airlie House classification
Early Treatment Diabetic Retinopathy Study (ETDRS – the modified Airlie House classification
For Diabetic Macular Edema
Intravitreal triamcinolone
In pseudophakic eyes intravitreal triamcinolone steroid injection followed by prompt laser is comparable to ranibizumab with regard to visual improvement and reduced retinal thickening.
This is a good therapeutic option in pregnancy or where there is a contraindication to anti-VEGF treatment (for example recent myocardial infarct).
For Diabetic Macular Edema
Intravitreal triamcinolone
In pseudophakic eyes intravitreal triamcinolone steroid injection followed by prompt laser is comparable to ranibizumab with regard to visual improvement and reduced retinal thickening.
This is a good therapeutic option in pregnancy or where there is a contraindication to anti-VEGF treatment (for example recent myocardial infarct).
For Diabetic Macular Edema
Intravitreal triamcinolone
In pseudophakic eyes intravitreal triamcinolone steroid injection followed by prompt laser is comparable to ranibizumab with regard to visual improvement and reduced retinal thickening.
This is a good therapeutic option in pregnancy or where there is a contraindication to anti-VEGF treatment (for example recent myocardial infarct).
