Measurement of the levator palpebrae superioris function (levator function) in ptosis assessment is clinically performed as:

• A Difference between the upper lid margin and light reflex (MRD1) in primary gaze
• B Width of the palpebral aperture in primary gaze
• C Distance between the upper lid crease and lash line
• D Excursion of the upper lid from downgaze to upgaze with frontalis muscle immobilized ✓

Explanation

Levator function (LF) is measured as the total excursion of the upper lid margin from full downgaze to full upgaze while the frontalis muscle is firmly blocked by the examiner's thumb to eliminate frontalis contribution. Normal LF is ≥ 15 mm; good = 8–15 mm; fair = 5–7 mm; poor = < 4 mm. MRD1 measures the amount of ptosis. Palpebral aperture is not a specific LF measure.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.