1 Ptosis Classification
Abstract
Ophthalmic plastic surgery of the upper face is nuanced. The surgeon must understand the anatomy of the upper face and the complex interplay between the eyebrow and the upper eyelid. In this chapter, a conceptual framework is created to classify and address a patient’s upper facial concerns. While the main goal of upper facial surgery is aesthetic enhancement and functional visual improvement, protection of the health of the eye must be paramount.
1.1 Introduction
It is critical for the surgeon to fully understand the patient’s upper facial concerns, and to recognize and analyze the causative anatomic and aging changes. Many times, the patient is unaware of, or even surprised by, the structural changes underlying his or her undesired appearance, and it is critical that the surgeon help the patient to understand the causative mechanisms preoperatively. There is no single formula to correct eyelid and eyebrow ptosis in all patients. Preoperatively, surgeons should categorize patients into groups that respond similarly to surgical procedures. While the main goal of surgery is eyelid and/or eyebrow elevation and improved cosmesis, the protection and health of the eye must be paramount. Realistic goals and expectations are necessary to produce a happy patient and a satisfied surgeon, and the surgeon and patient must be keenly aware that there will be a need for postoperative revisions in some cases.
1.2 Ptosis Classification
Many classification systems exist for upper blepharoptosis, including congenital and acquired versus mechanistic. 1 , 2 Frueh divided ptosis into four major categories. 2 We expand Frueh’s diagnostic categories to cover all types of ptosis (Table 1.1). When ptosis is classified correctly and levator excursion (function) is assessed accurately, clear patient management follows.
Evaluation of the eyebrows also requires careful examination and attention to detail. Eyebrow ptosis can be assessed by examining photographs from a patient’s youth and comparing them to the present state. Attention to the height, contour, and fullness of the eyebrow head, body, and tail is important. In general, with men, the eyebrow sits at the orbital rim and women prefer a slight temporal arch. This aesthetic norm may vary by ethnicity and age.
1.3 Preoperative Assessment
A thorough history of present illness and physical examination is necessary to adequately assess ptosis and develop a treatment plan.
1.3.1 History of Present Illness
Excellent patient care requires a thorough history of a patient’s concerns. A detailed history from the patient or family members is critical. The surgeon should ask about duration, timing, severity, and variability. Photographs from youth are helpful to establish or corroborate the time of onset. An acute problem may point to a neurogenic etiology such as a Horner syndrome or third nerve palsy, whereas a chronic problem suggests more benign etiologies. Variability in eyelid/facial position throughout the day or concurrent double vision suggests myasthenia gravis. A history of trauma may point to a traumatic ptosis, while a history of contact lens wear may suggest aponeurotic ptosis. Obtaining thorough family, medical, surgical, trauma, and drug histories is also important (Table 1.2).
Risk factor assessment prior to surgery is necessary. A history of ocular surface disease, anticoagulant use, prior eyelid or eye surgery, smoking, or other conditions like benign essential blepharospasm or snoring in sleep apnea may affect surgical decision-making.
1.3.2 Physical Examination
A complete ophthalmic examination should be performed, including visual acuity, pupillary size and response to light, extraocular motility, eyelid measurements, visual field testing, slit lamp examination focusing on the conjunctival and corneal surfaces and precorneal tear film, quantitative assessment for dry eyes by Schirmer’s testing, qualitative assessment for dry eye examining tear breakup time, and dilated funduscopic examination. Noting subtle abnormalities like pupil size or lower eyelid position can aid in diagnosis and treatment. Identifying preoperative asymmetry and conveying this to the patient can help manage postoperative result expectations.
Physical examination also includes noting head position, presence or absence of chin-up posture, eyebrow and eyelid position, and examination of the conjunctiva and fornices. Table 1.3 shows eyelid measurements that are critical to the categorization of the ptosis type (also see Fig. 1.1).
Assessing for variation of ptosis with jaw or extraocular muscle movement is important to detect synkinesis in Marcus Gunn jaw-winking ptosis or aberrant regeneration syndromes after cranial nerve III and VII palsies. Further, extraocular muscle dysfunction associated with ptosis occurs in myotonic dystrophies and congenital conditions like monocular elevation deficiency (superior rectus/levator muscle maldevelopment) and congenital oculomotor nerve palsy.
At times, pharmacologic testing confirms and localizes disease such as in Horner’s syndrome and in the fluctuating ptosis of myasthenia gravis. These tests are discussed in the neurogenic ptosis chapter.
Quantifying Ptosis
The vertical height of the palpebral fissures should be measured centrally with a millimeter ruler (Fig. 1.2). The amount of ptosis is measured as the difference between the margin reflex distance 1 (MRD1) (distance between the upper eyelid margin and central corneal light reflex) and 4 mm (the average MRD1). This average height varies by race. Comparison should be made to eyelid and eyebrow position from older photographs, and can be helpful for discussion and documentation about patient preference for eyelid and eyebrow height and contour.
Critical to the understanding of ptosis is Hering’s law of motor correspondence, which states that equal and simultaneous innervation flows to synergistic muscles concerned with the desired direction of gaze and eyelid elevation. Simply put, asymmetric bilateral upper eyelid ptosis or overcompensation for a contralateral ptosis (eyelid retraction) may be unmasked by lifting or occluding the ptotic eyelid and observing the fellow upper eyelid. In bilateral ptosis, the fellow eyelid will drop when lifting the more severely ptotic eyelid (Fig. 1.3). In pseudoeyelid retraction, the fellow eyelid will return to normal position.
Insurance companies frequently require visual field testing prior to eyelid surgery. It is performed first with the patient gazing straight ahead while the eyelid and eyebrow are relaxed, and then with the eyelid and eyebrow taped up to a normal position. The difference in visual field between the two positions is considered the deficit produced by the eyelid and/or eyebrow malposition. Typically, a 20 to 30% upper visual field change is considered a functional deficit and is covered by insurance. Testing with an automated perimeter or a tangent screen perimeter will document the visual field deficits.
Eye Protective Measurements
An adequate assessment of eye protective mechanisms is critical prior to surgery. The surgeon must explain to the patient that the eyelids and eyebrows are not purely decorative; they are designed to protect the cornea and preserve eye function. When lifting a ptotic eyelid, it is important to make sure that the eye remains adequately protected and can tolerate greater exposure to the outside world. The surgeon must document measurements of ocular motility and Bell’s phenomenon, tear film and dryness, orbicularis function (eyelid closure strength), lagophthalmos (eyelid opening on gentle eyelid closure), corneal sensation, and lower eyelid position and strength, each of which, if not normal, can negatively impact postoperative results. If the eyelid does not close well and there are poor corneal protective mechanisms, chronic eye pain due to exposure keratopathy or ulceration may become more likely after surgery.
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