Nocturnal lagophthalmos

Proper closure of the eyelid is essential to maintain a stable tear film and a healthy corneal surface. The seventh cranial nerve (facial nerve) arising from the brain innervates both eyebrow muscle and eyelid muscle. They control the opening and closure of the eyelid.
When eyes are  closed or blinked, tears wet the eyes to keep them healthy. If eyes are not closed  properly, they will become dry.
Some people are unable to close their eyelids completely. Such a condition is called Lagophthalmos.
The condition in which people sleep with their eyes open is known as "nocturnal lagophthalmos”.
Nocturnal lagophthalmos is the inability to close the eyelids during sleep and it may reduce the quality of sleep. It can lead to health problems over time causing exposure-related symptoms and if severe, causes corneal damage.
About 20% of people, including babies, suffer from this disorder.
The upper and lower eyelids contain seven structural layers namely, 1) skin and subcutaneous tissue, 2) orbicularis oculi muscle, 3) orbital septum, 4) orbital fat, 5) muscles of retraction, 6) tarsus and 7) conjunctiva.
Good eyelid closure may be lost due to the damage to or degeneration of any of these tissues.

Symptoms

The main symptom of Nocturnal lagophthalmos is the inability to close the eyelids during sleep. Other symptoms are,

• The feeling that something is rubbing against the eye (foreign body sensation)
• pain or irritation, especially in the morning due to increased corneal exposure
• dryness during sleep
• blurred vision due to unstable tear film.
• being sensitive to light
• getting red eyes
• increased tears

Causes

Nocturnal lagophthalmos can be caused by several things. Some people are born with this problem and this can be considered congenital. It can be minor (obscure lagophthalmos) or quite obvious.

Other causes may be

• shortened lid height,
• vertical shortening of the upper or lower eyelid causing incomplete closure during sleep
• damage to or degeneration of any of the tissues of upper and lower eyelids
• damage to the seventh cranial nerve, which controls the muscles in the eyelid.
• damage to the facial nerve may be due to injury, either from blunt trauma or a deep cut, stroke, Bell’s palsy(sudden weakness of the muscles in the face), tumors, especially acoustic neuromas, Möbius syndrome, autoimmune conditions, such as Guillain-Barré syndrome, cerebrovascular accidents
• damaged eyelids resulting from scarring from burns, injuries, or certain medical conditions, such as Stevens-Johnson syndrome, eyelid surgery, floppy eyelid syndrome
• protruding and sunken eyes
  
  Less common causes are
• Lyme disease, chickenpox, mumps, polio, Guillain-Barré syndrome, leprosy, diphtheria and botulism.
• Eyelid surgery -- Excessive removal of eyelid skin or muscle
• Overcorrection in ptosis (Droopy eyelid) repair
• floppy eyelid syndrome
• Graves' disease, which causes eyes to bulge forward.
  

Diagnosis

The underlying cause of the disorder can be assessed  by a doctor through the medical history and a physical exam by measuring the space between the eyelids with a ruler

• They also record how often the patient blinks, and how much the eyes close when it is done. They also assess the involvement of the facial nerve by the amount of force used to close the eyes.
• To observe any signs of damage to the eye, fluorescein eye stain test is done.
• To get a better look at the eyes, a slit lamp exam is done which involves using a microscope and bright light.
• Any epithelial defects or corneal ulcers should be carefully noticed.

Treatment

Lagophthalmos isn’t a dangerous condition, but it can ultimately lead to eye problems.   Depending on the cause, lagophthalmos can be treated with either surgery(surgical treatment) or products to help keep eyes moisturized and protected (non surgical treatment).

Nonsurgical treatment

• To prevent scratches, a protective ointment can be applied to the cornea throughout the day.
• In order to supplement the patient’s tear film, Non Preserved artificial tears should be administered frequently (at least four times per day).
• To keep eyes from drying out and itching, eye drops and ointments can be used as prescribed by the doctor.
• Moisture goggles may help protect and moisturize eyes while sleeping.
• For added moisture, a humidifier can be kept nearby while sleeping.
• To keep eyelids closed, doctor may suggest putting small weights or surgical tape on the outsides of eyelids.
• keeping a weighted implant such as Gold weight implantation or platinum (in case of allergy to gold ), in the eyelids may help eyes close correctly using gravity.
• Infectious corneal ulcers should be treated with appropriate antibiotic therapy
  
  

Surgical treatment

• In the case of  temporary condition, doctor may suggest tarsorrhaphy in which the cornea can be protected adequately by suturing eyelids together, either completely or partially.
• In the case of permanent tarsorrhaphy, a small opening remains to retain useful vision. Once healed, the doctor will enlarge the opening.
• If the facial nerve is paralysed, the doctor may suggest nerve and muscle transfers, implants, and facial reanimation procedures.