Ptosis

Abnormal drooping of the upper eyelid is called ptosis.
Normally, upper lid covers about upper one-sixth of
the cornea, i.e., about 2 mm. Therefore, in ptosis it
covers more than 2 mm.
Types and etiology
I. Congenital ptosis
It is associated with congenital weakness
(maldevelopment) of the levator palpebrae superioris
(LPS). It may occur in the following forms:
1. Simple congenital ptosis (not associated with
any other anomaly) (Fig. 14.32A).
2. Congenital ptosis with associated weakness of
superior rectus muscle.
3. As a part of blepharophimosis syndrome, which
comprises congenital ptosis, blepharophimosis,
telecanthus and epicanthus inversus (Fig. 14.32B).
4. Congenital synkinetic ptosis (Marcus Gunn jawwinking
ptosis). In this condition there occurs
retraction of the ptotic lid with jaw movements
i.e., with stimulation of ipsilateral pterygoid muscle.
II. Acquired ptosis
Depending upon the cause it can be neurogenic,
myogenic, aponeurotic or mechanical.
1. Neurogenic ptosis. It is caused by innervational
defects such as third nerve palsy, Horner’s
syndrome, ophthalmoplegic migraine and multiple
sclerosis.
2. Myogenic ptosis. It occurs due to acquired
disorders of the LPS muscle or of the myoneural
junction. It may be seen in patients with
myasthenia gravis, dystrophia myotonica, ocular
myopathy, oculo-pharyngeal muscular dystrophy
and following trauma to the LPS muscle.
3. Aponeurotic ptosis. It develops due to defects of
the levator aponeurosis in the presence of a
normal functioning muscle. It includes involutional
(senile) ptosis, postoperative ptosis (which is
rarely observed after cataract and retinal
detachment surgery), ptosis due to aponeurotic
weakness associated with blepharochalasis, and
in traumatic dehiscence or disinsertion of the
aponeurosis.
4. Mechanical ptosis. It may result due to excessive
weight on the upper lid as seen in patients with
lid tumours, multiple chalazia and lid oedema. It
may also occur due to scarring (cicatricial ptosis)
as seen in patients with ocular pemphigoid and
trachoma.
Clinical evaluation
Following scheme may be adopted for work up of a
ptosis patient:
I. History. It should include age of onset, family
history, history of trauma, eye surgery and variability
in degree of the ptosis.
II. Examination
1. Exclude pseudoptosis (simulated ptosis) on
inspection. Its common causes are: microphthalmos,
anophthalmos, enophthalmos and phthisis bulbi.
2. Observe the following points in each case:
i. Whether ptosis is unilateral or bilateral.
ii. Function of orbicularis oculi muscle.
iii. Eyelid crease is present or absent.
iv. Jaw-winking phenomenon is present or not.
v. Associated weakness of any extraocular
muscle.
vi. Bell’s phenomenon (up and outrolling of the
eyeball during forceful closure) is present or
absent.
3. Measurement of amount (degree) of ptosis. In
unilateral cases, difference between the vertical height
of the palpebral fissures of the two sides indicates
the degree of ptosis (Fig. 14.33). In bilateral cases it
can be determined by measuring the amount of cornea
covered by the upper lid and then subtracting 2 mm.
Depending upon its amount the ptosis is graded as
Mild 2 mm
Moderate 3 mm
Severe 4 mm
4. Assessment of levator function. It is determined
by the lid excursion caused by LPS muscle (Burke’s
method). Patient is asked to look down, and thumb of
one hand is placed firmly against the eyebrow of the
patient (to block the action of frontalis muscle) by
the examiner. Then the patient is asked to look up and
the amount of upper lid excursion is measured with a
ruler (Fig. 14.34) held in the other hand by the examiner.
Levator function is graded as follows:
Normal 15 mm
Good 8 mm or more
Fair 5-7 mm
Poor 4 mm or less
5. Special investigations. Those required in patients
with acquired ptosis are as follows:
i. Tensilon test is performed when myasthenia is
suspected. There occurs improvement of ptosis
with intravenous injection of edrophonium
(Tensilon) in myasthenia.
ii. Phenylephrine test is carried out in patients
suspected of Horner’s syndrome.
iii. Neurological investigations may be required to
find out the cause in patient with neurogenic
ptosis.
6. Photographic record of the patient should be
maintained for comparison. Photographs should be
taken in primary position as well as in up and down
gazes.
Treatment
I. Congenital ptosis. It almost always needs surgical
correction. In severe ptosis, surgery should be
performed at the earliest to prevent stimulus
deprivation amblyopia. However, in mild and moderate
ptosis, surgery should be delayed until the age of 3-
4 years, when accurate measurements are possible.
Congenital ptosis can be treated by any of the
following operations:
1. Fasanella-Servat operation. It is performed in
cases having mild ptosis (1.5-2mm) and good levator
function. In it, upper lid is everted and the upper tarsal
border along with its attached Muller’s muscle and
conjunctiva are resected (Fig. 14.35).
2. Levator resection. It is a very commonly performed
operation for moderate and severe grades of ptosis.
It is contraindicated in patients having severe ptosis
with poor levator function.
Amount of levator resection required: Most of the
surgeons find it out by adjusting the lid margin in
relation to cornea during operation on the table in
individual case. However, a rough estimate in different
grades of ptosis is as follows:
Moderate ptosis
Level of LPS Amount of LPS to be
Function resected
Good 16-17 mm (minimal)
Fair18-22 mm (moderate)
Poor 23-24 mm (maximum)
Severe ptosis
Fair levator 23-24 mm (maximum
function LPS resected)
Techniques. Levator muscle may be resected by either
conjunctival or skin approach.
i. Conjunctival approach (Blaskowics’ operation):
This technique is comparatively easy but not
suitable for large amount of resection. In it LPS
muscle is exposed by an incision made through
the conjunctiva near the tarsal border, after the
upper lid is doubly everted over a Desmarre’s lid
retractor (Fig. 14.36).
ii. Skin approach (Everbusch’s operation): It is a
more frequently employed technique. It allows
comparatively better exposure of the LPS muscle
through a skin incision along the line of future lid
fold (Fig. 14.37).
3. Frontalis sling operation (Brow suspension):
This is performed in patients having severe ptosis
with no levator function. In this operation, lid is
anchored to the frontalis muscle via a sling (Fig.
14.38). Fascia lata or some non-absorbable material
(e.g., supramide suture) may be used as sling.