Glaucoma is a chronic optic neuropathy and a leading cause of blindness worldwide. Structural changes to the optic disc can be detected earlier than functional vision loss, so assessing the disc is crucial. The Disc Damage Likelihood Scale (DDLS) was developed to incorporate disc size and focal rim width into grading glaucomatous damage. The DDLS provides a quantitative method for diagnosing, staging, and monitoring glaucoma progression. While it has limitations for some disc types, the DDLS correlates well with visual field loss when used properly.

1. Dr. Sumit Kumar
Department of Ophthalmology
Maulana Azad Medical College
and associated hospitals Delhi

2. • Glaucoma is a multifactorial, chronic optic neuropathy characterized by progressive retinal
ganglion cell death, optic disc cupping, and corresponding visual field loss mostly due to an
abnormally high intraocular pressure, and is a second leading cause of blindness worldwide.1-2
• Stuctural changes in optic disc precedes functional damage so their early assessment is crucial,
structural assessment can detect glaucoma in early stage and diminishes the risk of irreversible
visual imapiarement.

3. Disc pattern associated with glaucoma are progressive and asymmetric
Glaucomatous optic disc morphology can be divided into 3 categories:-
1.) Disc pattern Focal atrophy
Concentric atrophy
Deepening of cup
Pallor cup dicrepency
Advanced glaucomatous cupping
2.) Vascular sign Optic disc haemorrhage
Tortuous retinal vessels Baring of circumlinear blood vessel
Bayonetting of vessel
3.) Peripapillary changes RNFL Defect
β- zone peripapillary atrophy

4. FOCALATROPHY
o Selective Neural rim tissue loss primarily in
Inferotemporal region of the Optic Nerve Head
(Polar notching/focal notching)
+
o Lesser extent in the superotemporal sector in
early stage of damage.
Vertical enlargement of cup
o Characteristic of glaucoma especially with
average/normal IOP
CONCENTRIC ATROPHY
o Glaucomatous damage lead to enlargement of
cup in concentric circles.
o Because loss of neural rim tissue begins
temporally and then progress
circumferentially towards superior and
inferior pole this has been called Temporal
unfolding.
o Characteristic of glaucoma with high IOP

5. Focal notch is characteristic of glaucoma.
NOTCH is characterised by Rim/Disc ratio narrower than 0.1, limited to an area of less than 2
o’clock hour.

6. Since the late 1960s, the most commonly used quantitative classification of the optic nerve has been
Armaly’s cup/disc ratio. 3
This staging scale describes the disc using cup diameter as a percentage of overall disc diameter. The
cup/disc ratio, especially the vertical cup/disc ratio, represented a significant advance in quantifying
glaucomatous optic neuropathy.
Advatages- Ease of use and lack of magnification artifacts
Limitations-
1.) This system does not account for disc size.
2.) The second issue is that focal changes in the neuroretinal rim that are so
characteristic of glaucoma are not readily detected by the cup/disc ratio (doesn’t
consider the eccentricity of the cup)

7.  The disc damage likelihood scale (DDLS) was devised by Spaeth et al in 2002 to
incorporate the effect of disc size and focal rim width into a clinical
grading scale.4
 It is highly reproducible and does correlate strongly with the degree of field loss.5
 The system categorises the disc as small (<1.5mm), medium(1.5-2.0mm) or
large(>2.0mm). This ensures that the disc size is measured thereby reducing
misclassification bias based on disc size.

8. STEP 1. Perform dilation if necessary. The pupils must be sufficiently large to allow a clear view
of the fundus.
STEP 2. Get an idea of both of the patient’s optic nerves via a brief examination at the
biomicroscope with a strong plus lens (eg, +66.00 D). Determine the vertical size of the
discs. Disc size can be measured using a fundus lens at the slit-lamp. A slit beam is
directed onto the disc and the graticule at the top used to reduce the height of the beam
until it corresponds in size to the disc. The lens used will determine the correction
factor. A 66D gives the exact measure from the graticule.

9. Correction factors for the other lenses are -
Volk
60D-0.88
78D-1.1
90D-1.3
Nikon
60D-1
90D-1.63
Goldmann 3-mirror
1.27
STEP 3. Choose one of the patient’s eyes to concentrate on first. With a direct ophthalmoscope,
examine the optic disc for an area where its outer edge is clearly distinguished from other
ocular tissue such as sclera. Then, determine the full circumference of the outer edge.
STEP 4. Define the inside edge of the neuroretinal rim (outer edge of the cup) by direct
ophthalmoscopy. Estimate the rim-to-disc ratio by comparing the width of the neuroretinal
rim with that of the disc diameter on the same axis. Perform this comparison at several
clock positions. If the rim-to-disc ratio is different at various parts of the rim, note the area
at which the rim is narrowest and calculate the rim-to-disc ratio there.

10. STEP 5. Draw the shape of the optic disc. When sketching the neuroretinal rim’s inner edge, indicate
clear demarcation with a thick line and less clear demarcation with a thin or hatched line. Note
the course of blood vessels that help determine the rim’s width and any pertinent features of the
disc (eg, notches, pallor, hemorrhage).
STEP 6. Determine the DDLS by using your drawing of the disc, the narrowest rim-to-disc ratio, the size
of the disc, and the DDLS nomogram. If the nerve is smaller or larger than average, you must
adjust the DDLS score appropriately. An easy method is to stage the nerve as if it were of
average size and then increase the stage by one if the nerve is small or decrease the stage by
one if it is large. Note the DDLS score in the patient’s chart.
Repeat steps No. 3 through 6 for the patient’s other eye.

12. • DDLS provides a quantitative method of
assessing the glaucomatous damage.
• DDLS can be used for diagnosing, staging
and monitoring the rate of change of the
patient’s condition.
• Because each grade is assigned a numerical
value the system can then be used in
research settings to determine severity or
degree of progression.

13. GREEN ZONE
• All cases with IOP >40 mm Hg.
• Most cases with IOP >30 mmHg, especially where this represents a rise from previously lower pressure
and life expectancy is greater than one year.
• Marked anxiety about possible deterioration of disease.
YELLOW ZONE
• Life expectancy >2 year.
• All cases in which there is reasonable possibility that the glaucomatous disease process is active, that is, the
cause for developing disk damage will cause further disk damage.
RED ZONE
• All cases

14. • The DDLS cannot be used to evaluate certain types of discs, such as those that are
congenitally anomalous and Myopic discs may also be difficult to grade
• Another problem with the DDLS is that a disc may show progressive damage by having a
continuing generalized narrowing of the neuroretinal rim, but not have an increase in the
circumferential extent of rim absence. In such a situation the disc would unquestionably have
become worse, but the DDLS score will not change.

15. 1.Wang W, He M, Zhou M, Zhang X. Fornix-based versus limbus-based conjunctival flap in
trabeculectomy: a quantitative evaluation of the evidence. PLOS One. 2013;1-8.
2.Delbeke H, Stalmans I, Vandewalle E, Zeyen T. The Effect of Trabeculectomy on
Astigmatism.J Glaucoma. 2015;11;1-5.
3. Armaly M. Genetic determination of cup/disc ratio of the optic nerve. Arch Ophthalmol
1967;78:35-43.
4.Bayer A. Harasymowycz P. Henderer JD, et al. Validity of a new disc grading scale for
estimating glaucomatous damage: correlation with visual field damage. Am J Ophthalmol
2002;133:758-763.
5.Henderer JD, Liu C, Kesen M, et al. Reliability of the disc damage likelihood scale. Am J
Ophthalmol 2003;135:44-8.

16. It takes some effort to learn it and initially a copy of the table
should always be to hand. However, given practice and used
accordingly the DDLS is an excellent tool for classifying and
monitoring the optic nerve in glaucoma.