Introduction Ophthalmologists lack a facial nerve grading instrument (FNGI) that comprehensively encompasses the ophthalmic sequelae of facial nerve paralysis (FNP). Assessment and management of ophthalmic sequelae remains inconsistent, and outcomes of clinical studies are incomparable. We have developed and successfully adopted an FNGI based on four aspects of periorbital involvement: cornea, asymmetry, dynamic function and synkinesis. This CADS classification is specific for periorbital involvement, with objective and subjective parameters, to standardise grading. We present this classification and the results of a validation study in clinical practice.

Methods A cross-sectional, validation study. Two clinicians independently assessed and graded each patient on the same day, blinded to each other's grading. Each grader assigned a score to each of four parameters: C (0–3, ±a), A (0–2), D (0–3), S (0–2).

Results Thirty patients (19 females, mean age 60, range 30–84 years) with unilateral facial paralysis were graded. A total of 60 assessments were conducted. CADS scores ranged from C₀A₀D₁S₁ to C₃aA₂D₃S₀. In the first 30 assessments (of the first 15 patients), the two assessors disagreed over the corneal grading in four patients. The last 30 assessments of 15 patients showed complete agreement in all four parameters of the grading scale. The overall inter-observer agreement was 86.7% for cornea, 93.3% for resting asymmetry, 93.3% for dynamic function and 86.7% for synkinesis. After the first six patients, Cohen's κ reached 1 for all but synkinesis that ranged between 0.9 and 1.

Conclusions We present a validation study of an FNGI specifically designed for ophthalmic involvement of FNP. Objective and subjective parameters helped standardise grading and management planning.