Mind you, the term "ptosis" which means "droopy" does not merely refer to "droopy eyelid" as we can have something else droopy as well, not just our eyelid. As you know, the exact term for "droopy eyelid" is actually "blepharoptosis" (blepharo=eyelid, ptosis=droopy). But in our field of optometry, we are just comfortable to use "ptosis" rather than "blepharoptosis" in referring to "droopy eyelid"... and so will I do in this article as I'm lacking of time to type the whole lengthy word again and again.
Straight to the point requested by Br Muziman (my PBL group instructor), here are some of the popularly used ways in evaluating ptosis, and you can add them up if you have known another way that is not mentioned here. For any of the pictures below, you can get a clearer view simply by clicking it.
- Levator function is measured as the extent of eyelid movement on maximum down and up gaze. Method:
i. The thumb of one hand is placed at the eyebrow (don't press, just gently place) - this is to block the effect of forehead on the elevation of the eyelid.
ii. With another hand, hold a ruler near the patient's upper eyelid (with zero-point at the central upper lid margin) while the patient is looking downward (Pic. A & C)
iii. Then have the patient look upward as high as possible without any head movement, and take the measurement on the ruler at which the upper lid margin is now positioned (Pic. B & D).
- Classification of levator function: Good (≥8 mm), Fair (5-7 mm), Poor (≤4 mm)
- An accurate measurement of levator function may be used to determine the type of ptosis and also the best surgical approach to repair it. For instance in cases of involutional ptosis, the patient has a quite normal levator function despite the droopy eyelid.
2) Palpebral Fissure (labelled as PF in Pic. XYZ)
- a.k.a PAS (Palpebral Aperture Size) in our CL clinic
- Measured as distance between upper lid margin to lower lid margin passing through the center of pupil in primary gaze.
- Normal measurement: 9-10 mm
- a.k.a Margin Crease Distance (MCD) / Vertical Crease Distance (VCD)
- Crease height is the distance from the upper eyelid margin to the upper eyelid crease in downward gaze.
- Normal measurement: 5-10 mm
- MRD is the distance from the upper eyelid margin to the corneal reflex in primary gaze.
- Normal measurement: 4-5 mm
- MRD 1 +ve: if upper lid margin is higher than the level of corneal reflex.
- MRD 1 -ve: if upper lid margin is lower than the level of corneal reflex.
5) Margin Reflex Distance #2 (labelled as MRD2 in Pic. XYZ)
- MRD 2 is a distance between corneal reflex and lower lid margin in primary gaze.
- Measurement greater than 5 mm is considered normal.
SEVERITY of PTOSIS
- Bilateral ptosis: the amount of ptosis is measured as difference from the normal value (as given above), with larger difference indicates more severe ptosis.
- Unilateral ptosis: the amount of ptosis is taken as difference in PF / VCD / MRD 1 between RE and LE. Classification of ptosis based on difference between the 2 eyes: mild (2 mm), moderate (3 mm), severe (4 mm)
:: wallahu a'lam ::