Blepharoptosis is the drooping of the upper lid margin to a position that is lower than normal. The drooping may be worse after being awake longer, when the individual's muscles are tired. If severe enough and left untreated, the drooping eyelid can cause other conditions, such as amblyopia or astigmatism. This is why it is especially important for this disorder to be treated in children at a young age, before it can interfere with vision development.

Blepharoptosis may be due to a myogenic, neurogenic, aponeurotic, mechanical or traumatic cause and it usually occurs isolated, but may be associated with various other conditions, like immunological, degenerative, or hereditary disorders, tumors, or infections. Depending upon the cause it can be classified into congenital ptosis and acquired ptosis.

The vast majority of congenital ptosis is due to the levator muscle hypoplasia, or its control motor nerve oculomotor nerve (CN III) abnormalities or dysfunction. A small number of cases is due to the outer and medial horn of levator aponeurosis or the superior transverse ligament (Whitanall's) is too tight, or too much fiber adhesion to posterior wall of the orbital septum, thus limiting the movement of the levator muscle.

Congenital ptosis is more common in bilateral than unilateral, some patients have a family history. Ptosis can occur in isolation, may also be accompanied by other eye muscle paralysis or paresis, one of the most common is the superior rectus muscle palsy or inferior oblique muscle dysfunction.

Congenital ptosis can also be associated with ocular abnormalities: coexistent strabismus and amblyopia, Marcus Gunn's jaw-winking syndrome, blepharophimosis syndrome (triad of ptosis, telecanthus and phimosis of lid fissure), congenital anophthalmos or microphthalmos, and coexistent eyelid hamartoma, such as neurofibromas, hemangiomas or lymphangiomas.

Four types of acquired ptosis are divided: myogenic ptosis, traumatic ptosis, neurogenic and mechanical ptosis.

●myogenic ptosis

Myogenic ptosis can be divided to involutional myopathic and chronic progressive external ophthalmoplegia. The former which is also called senile ptosis, is the most common type. The levator aponeurosis is attached to the anterior tarsus, dermal attachments are maintained and therefore the supratarsal creases rises. Levator function is usually good. The other is chronic progressive external ophthalmoplegia, caused by the progressive muscular dystrophy affecting the extraocular muscles and levator, 5% of cases involve the facial and oropharyngeal muscles.

●traumatic ptosis

Traumatic ptosis is more common in unilateral. Upper eyelid lacerations, cuts, forceps injury, post-traumatic upper eyelid scar or edema, can lead to the levator muscle function diminished or disappeared.

●neurogenic ptosis

Neurogenic ptosis is a result of the oculomotor nerve lesions. The nature of the lesion may be a developmental abnormalities, trauma, cancer, inflammation, vascular disease and endocrine or metabolic diseases. This ptosis can exist alone, but most of them associated with other extraocular muscle paralysis, or abnormal collection of pupil movement. It is one of the signs of nervous system diseases.

●mechanical ptosis

Mechanical ptosis is caused by eyelid tumors, such as neurofibroma, hemangioma, lymphatic tumor and severe trachoma, which can increase the weight of the upper eyelid.

Pre-operative check-ups and correct judgment of the cause, type and extent of ptosis, are the basement of surgical method selection, the estimate of surgical results and the prevention of some kind of complications that may arise.

●determination of the degree of ptosis

Looking straight head, the upper eyelid covering the edge of the cornea is more than 2 mm, can be diagnosed blepharoptosis.

Compare with contralateral side if unilateral, the height difference of palpebral fissure is the amount of drooping. Normal eyelid margin is in the right middle horizontal line between the upper edge of pupil and the upper edge of cornea, which covers the cornea 1.5 -2 mm. To bilateral ptosis, displayed eyelid is located on the edge of the pupil, the droop is about 1-2mm, known as mild ptosis; upper eyelid covered 1/3 of the pupil, the droop is approximately 3-4mm, called moderate ptosis; such as eyelid edge whereabouts to the center of the pupil horizontal lines, sagging about 4mm or more, said severe ptosis.

●the levator muscle strength determination

Suppress thumb to supraorbital eyebrows to exclude levator role of frontalis muscle. Ask the patient gaze down, put a millimeter ruler in front of the face, zero point alignment on the lid margin, and the patient is then asked to look up as far as possible, the lid margin increase from the bottom up. Measure from extreme downward gaze to extreme upward gaze while immobilizing the brow, more than 10 mm is good, 5-10 mm is fair, and the poor is less than 5 mm.

●the superior rectus function test

The patient is asked to rotate eyeballs in all directions, and then close their eyes. Make eyelids open with your fingers to check whether the eyeballs rotate upward. If there is no turn, compared to the lack of Bellphenomenon, and it is not appropriate for ptosis corrective surgery because of postoperative exposure keratitis possibility. If surgery is necessary, the amount of correction should be conservative as far as possible, to reduce or eliminate lagophthalmos.

●exclude myasthenia gravis

For blepharoptosis patients with Honer syndrome, as well as Marcus Gunn's jawwinking syndrome, levator muscle should first be cut off and then correct the drooping, or else the symptoms would aggravate.

For congenital ptosis, since the palpebra frontalis covering some or all of the visual axis, the patients tend to frown and raise up their eyebrows to get rid of the interference, increasing and deepening the forehead wrinkles, even cervical spine deformities, thus congenital ptosis should be early corrected in principle. Early surgery could prevent amblyopia in children. If Marcus Gunn's jaw-winking syndrome exists, consider surgery only if the drooping was still obvious after puberty. If more than 10 mm of levator excursion (excellent), aponeurotic surgery or Müllerectomy is needed; if 5～10 mm of excursion (moderate), then levator resection or advancement; if 0～5 mm of excursion (poor), then need frontalis suspension. For those coexisted with microphthalmos, inner canthus epicanthus correction and outer canthus open angioplasty should first be made, six months before the correction of ptosis. For myogenic ptosis, the follow-up treatment should be postponed to 6 to 12 months later, allowing for recovery of myoneural dysfunction, resolution of edema and softening of scar. Blepharoptosis can also occur after cataract surgery from dehiscence of levator aponeurosis. For oculomotor nerve palsy caused ptosis, surgery could be operated only after the condition is in stable for 6 months. Accompanied by other external ophthalmoplegia or diplopia, diplopia should be corrected before surgery. Myasthenia gravis ptosis is not a contraindication for surgery if the myasthenia gravis is not progressive and the ptosis degree is fixed.

Conjunctival approach to excise tarsus, Muller's muscle, and conjunctiva should be considered only when levator function is excellent with minimal ptosis. Avoid external incision — therefore unable to alter supratarsal crease somewhat less predictable than external approaches. Resection of tarsus can result in postoperative floppy lid with lid peaking and eversion.

Anterior resection of skin, conjunctival resection of tarsus and conjunctiva, retention of levator and Muller's muscle.

Useful for mild to moderate ptosis.

Amenable to monitored anaesthesia technique.

Technique:

●Incise skin at desired supratarsal fold.

●Expose orbital septum and distal levator aponeurosis beneath orbicularis fibers.

●Incise septum and retract the preaponeurotic fat to expose the aponeurosis, which can be identified by the vertically oriented vessels on its superior surface.

●Incise distal aponeurosis at the superior tarsal border, and dessect it free from Muller's muscle.

●Place a central-lifting suture: double-arm 6-0 suture passed into superior tarsus and levator aponeurosis; tarsus will need to be recentered in cases of temporal displacement.

●If levator excursion is 8-10 mm, then upper lid should be slightly lower than the upper limbus after advancement; if 6-8 mm, then it should be at the limbus; if 4-6 mm, then slightly higher than limbus.

●Additional medial and lateral sutures are placed.

Perfomsupratarsal crease fixation—“anchor blepharoplasty” or resection of orbicularis.

Best used when levator function is fair

Sacrificies the viable levator muscle

Only useful in true levator dehiscence, which is likely only after trauma

Involves resuturing the dehisced end to the tarsus

●Required if levator function poor (congenital cases. Neurogenic cases)

●Can give 1 cm of excursion; good result in straightforward gaze; gives lagophthalmos while asleep, which requires ointment or nighttime patching.

●Incorporates a sling (fascia lata, temporalis fascia, homograft fascia, silicone strips, Gore-Tex) from frontalis to lid.

●For unilateral congenital cases, bilateral suspension performed to improve symmetry.

●Non-surgical modalities like the use of “crutch” glasses or special Scleral contact lenses to support the eyelid may also be used.

Ptosis that is caused by a disease will improve if the disease is treated successfully.

Ptosis surgery has many complications, according to the incidence from high to low order are as follows: undercorrection, overcorrection, excessive lagophthalmos, corneal exposure or keratitis, dry-eye syndrome, eyelid contour abnormality, temporal overcorrection, eyelid crease asymmetry, eyelash ptosis or lash abnormalities, entropion or ectropion/eversion of the upper lid, extraocular muscle imbalance, conjunctival prolapse.

amblyopia [æmbli'əʊpiə] n.弱视

anophthalmos ['ænəfθælməʊz] n.无眼畸形

aponeurotic [,æpənju'rɔtik] adj.腱膜的

astigmatism [ə'stigmətiz(ə)m] n.散光

blepharoptosis [,blefərə'tɔsis] n.眼睑下垂

conjunctiva [kən'dʒʌŋ(k)tivə] n.结膜

dehiscence [di'hisəns] n.裂开

diplopia [di'pləʊpiə] n.复视

hamartoma [hæmə'təumə] n.错构瘤

hemangiomas [hi,mændʒi'əumə] n.血管瘤

keratitis [kerə'taitis] n.角膜炎

lagophthalmos [lægɒf'θælmɒs] n.睑裂闭合不全

lymphangiomas [lim,fændʒi'əumə] n.淋巴管瘤

mechanical [mi'kænikəl] adj.机械的

microphthalmos [maikrəf'θælməʊz] n.小眼畸形

myasthenia [maiəs'θiːniə] n.肌无力

myogenic [maiə(ʊ)'dʒenik] adj.肌原性的

neurofibromas [njʊərə(ʊ)fai'brəʊmə] n.纤维神经瘤

neurogenic [njʊərə(ʊ)'dʒenik] adj.神经性的；起源于神经组织的

ophthalmoplegia [ɔf,θælmə'pliːdʒiə, ɔp-] n.眼肌麻痹

pupil ['pjupəl] n.瞳孔

senile ['siːnail] adj.高龄的

tarsus ['tɑːsəs] n.睑板

trachoma [trə'kəʊmə] n.沙眼

acquired ptosis 获得性上睑下垂

Blepharophimosis Syndrome 睑裂狭小综合征

congenital ptosis 先天性上睑下垂

levator muscle 提上睑肌

levator aponeurosis 提上睑肌腱膜

Marcus Gunn's Jaw-winking Syndrome 上颌瞬目综合征

myasthenia gravis 重症肌无力

oculomotor nerve (CN III) 动眼神经（第3对脑神经）

orbital septum 眶隔

superior transverse ligament (Whitanall's ligament) 上横韧带（Whitanall韧带）

supratarsal crease 重睑

triad of ptosis, telecanthus and phimosis of lid fissure 上睑下垂、内眦距离过宽、睑裂闭锁三联征