Disc Damage Likelyhood Scale (DDLS)

The Disc Damage Likelihood Scale (DDLS), developed by Spaeth and colleagues, remains a clinically useful, exam-based method for grading optic disc damage — it groups damage into severity categories useful for both diagnosis and monitoring change over time, and it doesn't require any equipment beyond a slit lamp and fundus lens.

DDLS staging table

*NW = narrowest width of the neuroretinal rim (rim-to-disc ratio). Note: the scale accounts for the rim width but not its location — location of narrowing matters clinically, especially early on, in distinguishing a true glaucomatous notch from a physiological/anatomic variant.

DDLS in the context of current imaging

OCT retinal nerve fiber layer (RNFL) and ganglion cell analysis have become the dominant quantitative tools for structural glaucoma assessment in well-resourced settings — offering reproducible, database-normed measurements that a clinical scale cannot match. That said, DDLS retains real practical value: it requires no equipment beyond a slit lamp, remains useful when OCT is unavailable or unreliable (e.g., high myopia with atypical disc anatomy, poor image quality), and reinforces disciplined clinical disc examination skills that shouldn't atrophy just because OCT exists. Residents should be comfortable with both — DDLS as a clinical exam skill, OCT RNFL/GCC as the quantitative gold standard where available.

Key reference: Spaeth GL, et al. The disc damage likelihood scale: reproducibility of a new method of estimating the amount of optic nerve damage caused by glaucoma. Trans Am Ophthalmol Soc. 2002.