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10. The margin fold distance is the distance from the upper eyelid margin to the fold of skin. This is also referred to as show. It forms an important landmark during ptosis repair.

11. Bell’s response should be assessed and lower eyelid laxity or scleral show should be appreciated which may alter the amount of ptosis repair. Confirmation of presence of Bell’s phenomenon is important before undertaking any surgical procedure to avoid risk of post operative exposure keratopathy. It is the upward rotation of eyeball on closure of the eye. This is referred to as Bell’s positive.

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Fig 5: Assessing the Bell’s phenomena.

12. The presence or absence of corneal sensations should be noted using a cotton wisp (Fig 6)

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Fig 6: Assessing the corneal sensation.

  1. Eyelid retraction may warrant thyroid function studies and the consideration of dysthyroid orbitopathy.
  2. Parinaud syndrome should be considered if convergence-retraction nystagmus and pupillary light-near disassociation is found in conjunction with eyelid retraction; neuroimaging should be obtained.
  3. The presence of proptosis in other eye may give appearance of pseudoptosis. Pseudoptosis can also result from microphthalmos, enophthalmos or anophthalmos, acquired hypotropia after a blowout fracture (orbital floor fracture), superior sulcus deformity, or contralateral vertical lid retraction.

Important points which would help you in Differentiating between a case of congenital and acquired ptosis

  1. The history of the patient is usually definitive which is helpful in establishing the diagnosis.
  2. Important points in favor of congenital simple ptosis is that the ptosis classically decreases in downgaze as the dystrophic levator muscle is neither able to contract nor to relax. Hence the measurements of the palpebral aperture in downgaze in the ptotic eye may at times be more than that in the contralateral normal eye in cases of unilateral ptosis.
  3. The upper eyelid crease is weak or absent in a case of moderate to severe congenital ptosis while in cases of acquired ptosis of a similar degree, the crease is higher than usual.
  4. Associated synkinesis is usually present with congenital ptosis. However, at times cases like congenital third nerve palsy with aberrant regeneration of the nerve may pose to be an important diagnostic dilemma.
  5. Variability and intermittency of symptoms usually indicates myasthenia. This history should be evaluated in every case of ptosis.
  6. Similarly, history of diplopia and the presence of ophthalmoplegia on examination indicate conditions like chronic progressive external ophthalmoplegias and warrant investigations for the same. 

Laboratory Studies:
If myasthenia gravis is suspected following may be needed:

  1. Serum assay for acetylcholine receptor antibodies
  2. Edrophonium chloride (Tensilon) test
  3. Single-fiber electromyography
  4. Repeated nerve stimulation test

In patients with chronic progressive external ophthalmoplegia following should be considered:

  1. Electrocardiogram
  2. Electroretinogram
  3. Electromyography
  4. Mitochondrial assay

Patients with suspected thyroid abnormalities should undergo tests for thyroid function including

  1. triiodothyronine (T3),
  2. thyroxine (T4),
  3. thyroid-stimulating hormone (TSH), and
  4. Imaging Studies

Other Tests

Tensilon Test

This test is done in doubtful cases where an acquired ptosis due to Myasthania Gravis is suspected. In adults 1 mg of neostigmine is injected I/M. The ptosis improves in 5 to 15 minutes if Myasthania gravis is the cause. Alternately 10 mg of edrophonium may be injected I/V. It is loaded in a tuberculine syringe and 2mg injected slowly in 15-30 seconds. The needle is left in situ and rest injected slowly if no untoward incident is observed. The effect occurs in 1 to 5 minutes if myasthenia is the cause. If cholinergic reaction occurs 0.5mg of atropine is given I/V.

Phenylephrine test

Sympathomimetic agents can be used to stimulate the Mueller muscle, as follows:
2.5% phenylephrine
10% phenylephrine: Be aware of cardiac complications.
0.5% apraclonidine: an alpha-adrenergic agonist.
1.0% apraclonidine: an alpha-adrenergic agonist.
Instill 2 drops on the eye under the eyelid (have the patient look down), wait 5 minutes, and assess any change in the palpebral fissure and the marginal reflex distance.
If no response is observed or if elevation is not adequate, external levator resection or advancement may be needed to correct the blepharoptosis.
If a good response is observed, the ptosis can be repaired by Mueller muscle–conjunctival resection.
Phenylephrine 10 % drops are used to assess mild cases of ptosis. Positive phenyephrine test suggests that patient would respond well to Muller’s muscle resection.

Jaw movements

The presence of jaw winking is assessed by moving the jaw from side to side (chewing movements), opening and closing the mouth.

Traction test

The lashes are held between the thumb and forefinger and traction applied. We look for the downward movement of the eyeball to rule out surgical or traumatic adhesion of upper lid with the globe. If the lid and the eye move independently no adhesion exists.
 

After all the history and examination you may classify ptosis as:

A.   Congenital Ptosis

  1. Congenital simple ptosis
  2. With oculomotor abnormalities (Superior Rectus muscle underaction; Double elevator palsy).
  3. Ptosis associated with the Blepharophimosis syndrome
  4. Synkinetic ptosis (associated with abnormal neural connections)
  5. Marcus Gunn Jaw Winking
  6. Misdirected third nerve ptosis

B. Acquired Ptosis

  1. Myogenic (Myasthenia gravis; CPEO)
  2. Neurogenic (Third Nerve palsy; Ophthalmoplegic migraine)
  3. Mechanical (Lid tumours)
  4. Aponeurotic
  5. Traumatic

C. Pseudoptosis

  1. Decreased intraorbital volume as may be associated with microphthalmia, anophthalmia, phthisis bulbi etc.
  2. Superior sulcus abnormality secondary to trauma or other causes.
  3. Ipsilateral hypotropia with the contralateral fixating eye.
  4. Contralateral lid retraction.
  5. Ipsilateral dermatochalasis or blepharochalasis

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