Diabetic Macular Edema

 

Table 1. International Diabetic Macular Clinical Edema Severity Scale
Propose Disease Severity Level	Findings Observable Upon Dilated Ophthalmoscopy
Diabetic macular edema apparently absent	No apparent retinal thickening or hard exudates in posterior pole
Diabetic macular edema apparently present	Some apparent retinal thickening or hard exudates in posterior pole
If diabetic macular edema is present, it can be categorized as follows:
Propose Disease Severity Level	Findings Observable Upon Dilated Ophthalmoscopy
Diabetic macular edema present	Mild diabetic macular edema: Some retinal thickening or hard exudates in posterior pole but distant from the center of the macula
	Moderate diabetic macular edema: Retinal thickening or hard exudates approaching the center of the macular but not involving the center
	Severe diabetic macular edema: Retinal thickening or hard exudates involving the center of the fovea

Source: American Academy of Ophthalmology Retina -Vitreous Panel. Preferred Practice Pattern® Guidelines. Diabetic Retinopathy.

 

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INTERNATIONAL CLINICAL DIABETIC RETINOPATHY DISEASE SEVERITY SCALE

 

Table 2. International Clinical Diabetic Retinopathy Disease Severity Scale
Proposed Disease Severity Level	Findings Observable Upon Dilated Ophthalmoscopy
No apparent retinopathy	No abnormalities
Mild NPDR	Microaneurysms only (Figure 13)
Moderate NPDR	More than just microaneurysms but less severe NPDR
Severe NPDR	US Definition Any of the following (4-2-1 rule) and no signs of proliferative retinopathy: Severe intraretinal hemorrhages and microaneurysms in each of four quadrants Definite venous beading in 2 or more quadrants (Figure 14) Prominent IRMA in 1 or more quadrants (Figure 15) International Classification Any of the following and no signs of PDR More than 20 intraretinal hemorrhages in each of four quadrants Definite venous beading in two or more quadrants Prominent IRMA in one or more quadrants
PDR	One of both of the following: Neovascularization (Figure 10) Vitreous/preretinal hemorrhage (Figure 12)

IRMA = intraretinal microvascular abnormalities; NPDR = nonproliferative diabetic retinopathy; PDR = proliferative diabetic retinopathy

Source: American Academy of Ophthalmology Retina-Vitreous Panel. Preferred Practice Pattern® Guidelines. Diabetic Retinopathy. 

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Diabetic Retinopathy Classification ETDRS

 

Clinically-significant macular edema (CSME)

Clinically Significant Macular Edema

Clinically Significant Macular Edema

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 A zone of thickening larger than 1 disc area if located within 1 disc diameter of the center of the macula

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Proliferative vitreoretinopathy classification

 Proliferative vitreoretinopathy Grading

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VMA vs VMT

Entity	OCT-based definition	Additional features	Symptom	Corresponds to full thickness macular hole (FTMH) stage:
Vitreomacular adhesion (VMA)	The following must be present on at least one OCT B-scan image: (i) Partial vitreous detachment as indicated by elevation of cortical vitreous above the retinal surface in the perifoveal area (ii) Persistent vitreous attachment to the macula within a 3-mm radius from the center of the fovea (iii) Acute angle between posterior hyaloid and inner retinal surface (iv) Absence of changes in foveal contour or retinal morphology	None	None	Stage 0 (Other eye should have full thickness macular hole)
Vitreomacular traction (VMT)	The following must be present on at least one OCT B-scan image: (i) Partial vitreous detachment as indicated by elevation of cortical vitreous above the retinal surface in the perifoveal area (ii) Persistent vitreous attachment to the macula within a 3-mm radius from the center of the fovea (iii) Acute angle between posterior hyaloid and inner retinal surface (iv) Presence of changes in foveal contour or retinal morphology (distortion of foveal surface, intraretinal structural changes such as pseudocyst formation, elevation of fovea from the retinal pigment epithelium (RPE), or a combination of any of these three features) (v) Absence of full thickness interruption of all retinal layers	Foveal pseudocyst, macular thickening, retinal capillary leakage (typically isolated VMT alone does not cause leak on fluorescein angiography), macular schisis, cystoid macular edema, retinal detachment	Reduced or distorted vision	Stage 1 (VMT only, i.e. impending macular hole) OR Stage 2 (VMT with small/medium FTMH) OR Stage 3* (VMT with medium/large FTMH)

 

Entity	OCT-based classification
Vitreomacular adhesion (VMA)	(i) Focal: Width of attachment ≤1500 μm (ii) Broad: Width of attachment >1500 μm
	(i) Concurrent: Associated with other macular abnormalities (e.g. age-related macular degeneration, retinal vein occlusion, diabetic macular edema) (ii) Isolated: Not associated with other macular abnormalities
Vitreomacular traction (VMT)	(i) Focal: Width of attachment ≤1500 μm (ii) Broad: Width of attachment >1500 μm
	(i) Concurrent: Associated with other macular abnormalities (e.g. age-related macular degeneration, retinal vein occlusion, diabetic macular edema) (ii) Isolated: Not associated with other macular abnormalities

With age, the vitreous gel undergoes liquefaction forming pockets of fluid within the vitreous (synchysis) which leads to a contraction or condensation (syneresis) of the vitreous. With loss of vitreous volume, there is a tractional pull exerted at sites of vitreoretinal and vitreopapillary attachments by means of the condensing dense vitreous cortex.

At the same time, there is weakening of these attachments between the vitreous and the internal limiting membrane (ILM) and it is proposed that detachment of the posterior hyaloid proceeds in the following sequence:

(i) Perifoveal region (possibly, temporal followed by nasal)

(ii) Superior and inferior vascular arcades

(iii) Fovea

(v) Mid-peripheral retina

(vi) Optic disc (when vitreous is detached fully from the optic disc, commonly associated with the Weiss ring, it is called a complete PVD)

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Retinopathy of Prematurity Classification

Retinopathy of Prematurity

Zone 1	Circle centered on nerve with radius twice the distance from nerve to fovea
Zone 2	Circle extending to ora serrata nasally
Zone 3	Temporal crescent extending to ora serrata temporally

Stage

Stage 0	Immature vascularization, no ROP
Stage 1	Demarcation line
Stage 2	Ridge
Stage 3	Extraretinal fibrovascular proliferation
Stage 4	Partial retinal detachment Stage 4A – extrafoveal Stage 4B – foveal
Stage 5	Total retinal detachment Funnel: Anterior or posterior, open or closed

Plus Disease

Plus disease	– At least 2 quadrants of venous dilation and tortuosity – Vitreous haze – Failure of pupil to dilate – Preretinal or vitreous hemorrhage
Pre-plus disease	Abnormal dilation and tortuosity not sufficient to meet plus criteria
Threshold disease	5 contiguous or 8 non-contiguous clock hours of extraretinal neovascularization in zone 1 or zone 2 with plus disease
Aggressive posterior ROP (rush disease)	Posterior location, prominence of plus disease, ill-defined nature of retinopathy

ETROP Classification

Type 1 ROP	Zone I, any stage with plus disease Zone I, stage 3 without plus disease Zone II, stage 2 or 3 with plus disease
Type 2 ROP	Zone I, stage 1 or 2 without plus disease Zone II, stage 3 without plus disease

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Dry Eye grading/Meibomian Gland Dysfunction staging

Dry Eye/Meibomian Gland Dysfunction

Grade	1	2	3	4
Discomfort severity	Mild episodic	Moderate	Severe frequent	Severe disabling
Visual symptoms	None	Annoying or episodic activity limiting	Annoying chronic or chronic activity limiting	Constant or disabling
Conjunctival injection	None to mild	None to mild	+/-	+/++
Conjunctival staining	None to mild	Variable	Moderate to marked	Marked
Corneal staining	None to mild	Variable	Marked central	Severe punctate erosions
Corneal/tear signs	None to mild	Mild debris, decreased meniscus	Filamentary keratitis, mucus clumping, increased tear debris	Filamentary keratitis, mucus clumping, increased tear debris, ulceration
Lid/MG	MGD variably present	MGD variably present	Frequent	Trichiasis, keratinization, symblepharon
TBUT	Variable	<=10	<=5	Immediate
Schirmer score	Variable	<=10	<=5	<=2

 

Meibomian Gland Dysfunction (MGD) Staging

Stage	MGD Grade	Symptoms	Corneal Staining
1	+ (minimally altered expressibility and	None	None
2	++ (mildly altered expressibility and secretion quality)	Minimal to mild	None to limited
3	+++ (moderately altered expressibility and secretion quality)	Moderate	Mild to moderate; mainly peripheral
4	++++ (severely altered expressibility and secretion quality)	Marked	Marked; central in addition
“Plus” disease – co-existing or accompanying disorders of the ocular surface and/or eyelids

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Revised Gass & IVTS Classification- Macular Hole

 There are two main classification schemes for macular holes.

Gass first described his clinical observations on the evolution of a macular hole:

Stage 1 MH, or impending MH, demonstrates a loss of the foveal depression. 

A stage 1A is a foveolar detachment characterized a loss of the foveal contour and a lipofuscin-colored spot. 

A stage 1B is a foveal detachment characterized by a lipofuscin-colored ring.

Stage 2 MH is defined by a full thickness break < 400µm in size. It might be eccentric with an inner layer “roof.” This can occur weeks to months following Stage 1 MHs. A further decline in visual acuity is also noted. In most cases, the posterior hyaloid has been confirmed to be still attached to the fovea on OCT analysis.

Stage 3 MH is further progression to a hole ≥400 µm in size. Nearly 100% of stage 2 MHs progress to Stage 3 and the vision further declines. A grayish macular rim often denotes a cuff of subretinal fluid. The posterior hyaloid is noted to be detached over the macula with or without an overlying operculum 

Stage 4 MH is characterized by a stage 3 MH with a complete posterior vitreous detachment and Weiss ring.

Stage 0	Vitreomacular adhesion
Stage 1	Impending macular hole, vitreomacular traction syndrome  Stage 1A – foveal pseudocyst, schisis in inner fovea  Stage 1B – break in outer fovea
Stage 2	Early full-thickness macular hole  Less than 400um diameter
Stage 3	Large full-thickness macular hole  Greater than 400um diameter
Stage 4	Full-thickness macular hole with complete PVD

More recently, the The International Vitreomacular Traction Study (IVTS) Group also formed a classification scheme of vitreomacular traction and macular holes based on OCT findings[5]:

Vitreomacular adhesion (VMA): No distortion of the foveal contour; size of attachment area between hyaloid and retina defined as focal if </= 1500 microns and broad if >1500 microns

Vitreomacular traction (VMT): Distortion of foveal contour present or intraretinal structural changes in the absence of a full-thickness macular hole; size of attachment area between hyaloid and retina defined as focal if </= 1500 microns and broad if >1500 microns

Full-thickness macular hole (FTMH): Full-thickness defect from the internal limiting membrane to the retinal pigment epithelium. Described 3 factors: 

1) Size -- horizontal diameter at narrowest point: small (≤ 250 μm), medium (250-400 μm), large (> 400 μm); 

2) Cause -- primary or secondary; 

3) Presence of absence of VMT

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