Many elements are involved in the evaluation of blepharoptosis. The history can provide pertinent clues, such as variability in the degree of ptosis, which suggests myasthenia gravis. Affected family members may highlight potential heritable conditions such as oculopharyngeal or myotonic dystrophy. The physical examination further elucidates etiology through eyelid measurements, assessment of surrounding orbital and facial structures, and observation of head positioning and possible synkinetic movements. The pupils and tear film are also assessed. Further ancillary testing may be guided by additional history and clinical exam findings.
Physical examination of the ptosis patient begins with 5 clinical measurements (Video 12-3, Fig 12-11):
margin–reflex distances 1 and 2
vertical palpebral fissure height
upper eyelid crease position
levator function (upper eyelid excursion)
presence of lagophthalmos
Eyelid measurements. Courtesy of Richard C. Allen, MD, PhD.
The margin–reflex distance 1 (MRD1), which is the distance from the upper eyelid margin to the corneal light reflex in primary position, is the single most important measurement in describing the amount of ptosis. In severe ptosis, the light reflex may be obstructed by the eyelid, and the MRD1 has a zero or negative value. The more ptotic eyelid should be elevated to unmask occult contralateral ptosis according to Hering’s law of equal innervation (Fig 12-12). If the patient reports visual obstruction while reading, the eyelid position in downgaze is checked. Lower eyelid retraction (or scleral show) should be noted separately as the margin–reflex distance 2 (MRD2). The MRD2 is the distance from the corneal light reflex to the lower eyelid margin. The sum of the MRD1 and the MRD2 should equal the vertical palpebral fissure height.
Figure 12-11 Evaluation of ptosis. Patient appearance and example of a ptosis data collection sheet.
(Courtesy of Bobby S. Korn, MD, PhD.)
Figure 12-12 Unmasking of right upper eyelid ptosis (arrow) with elevation of ptotic left upper eyelid, demonstrating the effect of Hering’s law of equal innervation.
(Courtesy of Don O. Kikkawa, MD.)
The vertical palpebral fissure is measured at the widest point between the lower eyelid and the upper eyelid. This measurement is taken with the patient fixating on a distant object in primary gaze.
The distance from the upper eyelid crease to the eyelid margin is measured. Because the insertion of fibers from the levator muscle into the skin contributes to formation of the upper eyelid crease, high, duplicated, or asymmetric creases may indicate an abnormal position of the levator aponeurosis. In the typical non-Asian eyelid, the upper eyelid crease is 8–9 mm in males and 9–11 mm in females. The crease is often elevated in patients with involutional ptosis and is often shallow or absent in patients with congenital ptosis. As a normal anatomic finding, the upper eyelid crease is typically lower or obscured in the Asian eyelid, with or without ptosis.
Levator function is estimated by measuring the upper eyelid excursion from downgaze to upgaze with frontalis muscle function negated. Fixating the brow with digital pressure minimizes contributions from accessory elevators of the eyelids such as the frontalis muscle. Failure to negate the influence of the frontalis muscle results in overestimation of levator function, which may affect the diagnosis and treatment plan.
Finally, the patient should be assessed for lagophthalmos; if it is present, the gap between the eyelids should be measured and the amount noted (in millimeters). Lagophthalmos and poor tear film quantity or quality may predispose the patient to complications of ptosis repair such as dryness and exposure keratopathy.
Physical examination also includes checking head position, chin elevation, brow position, and brow action in attempted upgaze. These features help to show the patient how ptosis affects function. Quantity and quality of the tear film is documented in the initial examination.
The examiner should also note the presence or absence of supraduction of the globe with eyelid closure (Bell phenomenon) and assess corneal sensation; these factors may affect the treatment plan.
Variation in the amount of ptosis with extraocular muscle or jaw muscle movements (synkinesis) occurs in several conditions, including Marcus Gunn jaw-winking ptosis, aberrant regeneration of the oculomotor nerve or the facial nerve, and some types of Duane retraction syndrome. The examiner should attempt to elicit synkinesis as part of the evaluation of patients with congenital blepharoptosis or those with possible aberrant regeneration.
The position of the ptotic eyelid in downgaze (palpebral fissure in downgaze) can help differentiate between congenital and acquired causes. The congenitally ptotic eyelid is typically higher in downgaze than the contralateral normal eyelid. The congenitally ptotic eyelid may also manifest lagophthalmos. By contrast, in acquired involutional ptosis the affected eyelid remains ptotic in all positions of gaze and may even worsen in downgaze with relaxation of the frontalis muscle.
The ophthalmologist must assess visual function and refractive error in all cases of congenital or childhood ptosis in order to identify and treat the child with concomitant amblyopia resulting from anisometropia, high astigmatism, strabismus, or occlusion of the pupil. Amblyopia occurs in approximately 20% of patients with congenital ptosis. Extraocular muscle function should also be assessed because extraocular muscle dysfunction associated with ptosis occurs in various congenital conditions (combined superior rectus/ levator muscle maldevelopment, congenital oculomotor palsy) and acquired conditions (ocular or systemic myasthenia gravis, chronic progressive external ophthalmoplegia, oculopharyngeal dystrophy, and oculomotor palsy with or without aberrant regeneration).
In addition, pupillary examination is important in the evaluation of ptosis. Pupil abnormalities are present in some acquired and congenital conditions associated with ptosis (eg, Horner syndrome, cranial nerve III palsy). Miosis that is most apparent in dim illumination is a finding in Horner syndrome; mydriasis is seen in some cases of oculomotor nerve palsy.
External examination may reveal other abnormalities as well. For example, severe bilateral congenital ptosis may be associated with telecanthus, epicanthus inversus, hypoplasia of the superior orbital rims, horizontal shortening of the eyelids, ear deformities, hypertelorism, and hypoplasia of the nasal bridge. These findings are classically seen in blepharophimosis–ptosis–epicanthus inversus syndrome (BPES; discussed in Chapter 10).
Visual field testing may be used to quantitate the patient’s level of functional visual impairment. Comparison of visual fields with eyelids elevated with tape to those with eyelids in their natural ptotic state gives an estimate of the superior visual field improvement that can be anticipated following surgery. Visual field testing and external full-face photography may be required by third-party payers for insurance coverage.
Pharmacologic testing, pupillary evaluation in light and dark, and lower eyelid elevation (smaller MRD2) may be helpful in confirming the clinical diagnosis of Horner syndrome and in localizing the causative lesion (see BCSC Section 5, Neuro-Ophthalmology). Third-order neuron dysfunction resulting in Horner syndrome is typically benign. However, neuron dysfunction of the first or second order is sometimes associated with malignant neoplasms such as an apical lung (Pancoast) tumor, aneurysm, or dissection of the carotid artery.
Pharmacologic testing may also be used in the diagnosis of myasthenia gravis (MG), a disease in which ptosis is the most common presenting sign. Fluctuating ptosis that seems to worsen with fatigue or prolonged upgaze—especially when accompanied by diplopia or other clinical signs of systemic MG such as dysphonia, dyspnea, dysphagia, or proximal muscle weakness—is an indication for further diagnostic evaluation with the edrophonium chloride, ice-pack, or acetylcholine receptor antibody tests. (Also see the section “Myasthenia gravis.”)
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.