ptosis

PtosisBY: DIMA LOTFIE13901022

What is ptosis?

From the Greek word "to fall" Drooping of the eyelid. can be bilateral or unilateral.

Anatomy of the eyelid : surface anatomy

The upper eyelid extends superiorly to the eyebrow, which separates it from the forehead.

The lower lid extends below the inferior orbital rim to join the cheek, forming folds where the loose connective tissue of the eyelid is juxtaposed with the denser tissue of the cheek.

Anatomy of the eyelid: Layers

The eyelid consists of 5 layers: (from outside to inside)

1- skin and subcutaneous tissue 2- orbicularis muscle 3- levator APONEUROSIS 4- tarsal plate 5- conjunctiva

Anatomy of the eyelid: nerves

Sensory innervation of the eyelids is achieved by trigeminal nerve, it supplies somatosensory innervation to the eyelid via its ophthalmic and maxillary divisions.

Terminal branches of the ophthalmic division supply the upper eyelid as the lacrimal, supraorbital, and supratrochlear nerves (lateral to medial).

Motor: Eyelid muscle innervation is achieved by cranial nerve VII (the facial nerve), cranial nerve III (the oculomotor nerve), and sympathetic nerve fibers.

Anatomy of the eyelid: vessels

The internal and external carotid arteries contribute to lid arterial supply.

The internal carotid arterial supply is from the terminal branches of the ophthalmic artery medially (giving supraorbital, supratrochlear, and dorsal nasal branches) and the lacrimal artery laterally.

The external carotid artery contributes via branches of the facial artery, the superficial temporal artery, and the infraorbital artery.

Anatomy of the eyelid: vessels cont…

The facial artery provides the angular artery, which passes to the medial canthal region, anastomosing with the dorsal nasal artery.

The superficial temporal artery supplies eyelid anastomoses via the transverse facial and zygomatic branches.

The infraorbital artery exits the infraorbital foramen as a terminal branch of the maxillary artery, anastomosing with vessels of the lower eyelid.

Anatomy of the eyelid: lymphatics

The eyelids have a rich lymphatic drainage. The drainage of most of the upper lid and the lateral half of the lower lid is to the preauricular lymph nodes.

The medial portion of the upper lid and the medial half of the lower lid drain into the submandibular nodes by way of vessels that follow the angular and facial vessels.

What muscles are responsible for eyelid retraction?

1- levator palpebrae superioris (most important and most commonly affected in ptosis)

2- Müller's muscle 3- frontalis muscle

Normal lid position

Upper lid covers 1\6 of cornea (2 mm )

Not showing the sclera from above. Lower lid touches the limbusYou can see part of the sclera from below.

Causes of ptosis

Can be classified into congenital and acquired.

1- Congenital: Levator Muscle dystrophy:congenital weakness (maldevelopment) of the levator palpebrae superioris (LPS).

Causes Cont…

2- Acquired (more important to know): Classified into:1- Neurogenic*2- Myogenic*3- Aponeurotic*4- Mechanical

Acquired ptosis:

1- Neurogenic: (problem with the nerve supply to LPS) Can be 3rd cranial nerve palsy Horner’s syndrome (remember The classic triad for

Horner's syndrome includes unilateral ptosis, ipsilateral miosis, and anhidrosis)

Multiple sclerosis

Acquired ptosis cont…

2- Myogenic: the problem is in the muscle itself or in the myoneural

junction:E.g: Myasthenia gravis (in 85% of patient with myasthenia gravis, ptosis can be the initial symptom) Could be due to myotonic dystrophy Or trauma to the LPS muscle.

Acquired ptosis cont…

3- Aponeurotic (problem in the aponeurosis which connects the muscle to the tarsal plate) Could be due to defect in the insertion or weakness of the

aponeurosis of the LPS muscle P.s : Aponeurotic ptosis is the most common type seen in

adults especially in old age. Clinically: the crease is often elevated (in mild ptosis) or

absent (in severe ptosis).

In the picture you see bilateral aponeurotic ptosis, Note the elevated lid creases. There is compensatory frontalis over-activation, causing elevation of the brows.

Acquired ptosis cont…

4- Mechanical: due to excessive weight on the upper lid Tumor Edema Dermatochalasis : excess of skin in the eyelid, also

known as "baggy eyes." Anterior orbital lesions

Clinical Evaluation Of Ptosis

We need to know how severe ptosis is in order to manage it.

- In history taking, there are 5 main things you should focus on:1- Onset2- family history3- history of trauma4- Any eye surgery?5- Variability in degree of ptosis

Clinical Evaluation cont…

2- In clinical examination, most important two things you should do: 1- Measure the severity of ptosis 2- Asses LPS muscle functionBut first you should:• Exclude pseudoptosis (simulated ptosis)• Observe if ptosis is unilateral or bilateral• Observe the function of orbicularis oculi muscle (its function is to close the eyelid)• Check if eyelid crease is present or absent

Also..

• Check if Jaw-winking phenomenon is present or notIt is an associated winking motion of the affected eyelid on the movement of the jaw, it's thought to be due to a congenital misdirection of the fifth cranial nerve fibers into a branch of the third cranial nerve that supplies levator muscle• Associated weakness of any extraocular Muscle• Bell’s phenomenon is present or absent: (an upward and outward movement of the eye, when an attempt is made to close the eye).

Now you can measure the amount (degree) of ptosisBy using marginal reflex distance (MRD); it's the distance between upper lid margin and light reflex. (It measures how many millimeters of the cornea are covered by the upper lid) Normal MRD should be less than 2mm. 2 mm of droop = mild ptosis 3-4 mm of droop = moderate ptosis More than 4mm = severe ptosis - Why do we call it severe? Because at this stage, the lid starts covering the pupil ➡ affects the vision

LPS function assessment

In left hand, you should hold the eyebrow of the patient (to prevent frontalis muscle to play any role in elevating the lid), then ask the patient to look down, then to look up ➡ measure the distance between the upper and lower gaze ..

(Measuring the distance between down gaze and up gaze will tell you how many millimeters LPS can actually lift your lid)

Ideally, distance should be 12mm. The less the distance between upper and lower gaze = the poorer the LPS

muscle function Less than 4mm indicates VERY poor LPS function. 4-8 mm = moderate function More than 8 mm is considered as a reasonably good function.

Additional notes

1- in congenital ptosis it's necessary to FIRST identity how severe it is because it can lead to amblyopia.. ➡ management of ptosis in this case is operation.2- We need to asses the function of LPS muscle in order to decide the management; we can do recession or resection if the function of LPS is still

average. But if the muscle has a very poor function or lost its function

completely, resection or recession won't help.. In that case we try to use the alternate muscle that can help elevating the lid (frontalis muscle).

Treatment

If myasthenia gravis is diagnosed, treatment should be initiated by a neurologist.

In certain cases, a patient may not want to undergo surgery. Glasses can be made with a crutch attachment that can hold up the lid.

1- If levator function is poor (< 4 mm) or absent, the use of frontalis slings can achieve desirable postoperative results.

2- A levator advancement or resection results in shortening of the levator aponeurosis and muscle. The levator can be approached from an anterior or posterior direction.

An incision is made by using the natural lid crease, if present, to allow for direct visualization of the aponeurosis. Once the levator aponeurosis is identified, it is disinserted from the tarsus, advanced and/or resected, and reattached. The amount of advancement depends on the degree of ptosis being treated. The aponeurosis also is attached to the skin to reform the crease.

References:

Kanski's clinical ophthalmology 8th edition Medscape.com eyewiki.aao.org ncbi.nlm.nih.gov

Thank you! :)