Medical condition
Exposure keratopathy
(also known as
exposure keratitis
) is medical condition affecting the
cornea
of
eyes
. It can lead to
corneal ulceration
and permanent
loss of vision
due to
corneal opacity
.
Normally, corneal surface is kept moist by blinking. during sleep, it is covered by
lids
. Increased corneal exposure to the air due to incomplete or inadequate eyelid closure cause increased evaporation of tear from corneal surface. Increased evaporation of tear cause instability of the tear film and dryness of corneal surface. This will lead to
corneal epithelial
damage. Both
tear film
and corneal epithelium play significant role in corneal protective mechanism.
[1]
[2]
The dryness and epithelial damage will allow micro organism to penetrate cornea and thus
keratitis
occurs.
Signs and symptoms
[
edit
]
Symptoms are similar to dry eye.
[3]
Patients may complain
redness
, irritation, ocular discomfort, burning, and foreign body sensation. Punctate epithelial defects, epithelial break down and stromal melting may be seen in corneal examination.
[3]
Corneal ulceration may develop due to bacterial invasion.
Complications
[
edit
]
Main complication of exposure keratopathy is permanent vision loss due to corneal opacification. Stromal melting may occasionally lead to corneal perforation.
[3]
Causes
[
edit
]
Exposure keratopathy may occur due to mechanical eyelid abnormalities or neuro-paralytic corneal anesthesia. It may occur secondary to ocular surgeries like
blepharoplasty
, ptosis surgery etc. also.
[3]
Lagophthalmos
[
edit
]
Lagophthalmos
, the inability to close the eyelids completely is the main cause of exposure keratopathy. Common cause of lagophthalmos is
facial nerve
(CN VII) palsy. Facial nerve function may affect in several conditions like
cerebrovascular accident
,
head trauma
,
brain tumors
,
Bell's palsy
etc. Physiological inability to close the eyelids during sleep (nocturnal lagophthalmos) may also cause exposure keratopathy.
[4]
Mechanical causes
[
edit
]
Chemical or thermal burns to eyelids or
conjunctiva
,
ocular cicatricial pemphigoid
, or
symblepharon
may cause incomplete or inadequate eyelid closure.
Exophthalmos
[
edit
]
Exophthalmos is the unilateral or bilateral bulging of the eye anteriorly out of the orbit causing increased exposure of cornea. It may be seen in many conditions like
Graves' ophthalmopathy
,
[5]
Orbital cellulitis
,
Orbital pseudotumor
etc.
[6]
Surgical
[
edit
]
A weak bell phenomenon may result in exposure keratopathy after
ptosis
surgery.
[3]
Postoperative lagophthalmos following blepharoplasty is another common cause of secondary exposure keratopathy.
[7]
Diagnosis
[
edit
]
Fluorescein
staining may be used to detect for epithelial defects, corneal infection or perforation of the cornea.
[8]
Tear break-up time
and
ocular protection index
assessment can be done to reveal
dry eye
.
Exophthalmometry
can be used to measure degree of exophthalmos.
Prevention
[
edit
]
If increased corneal exposure is detected, several preventive measures can be done to prevent keratitis. Aritificial eye drops and eye ointments may be used to keep the eyes moist.
[3]
Since frequent use of eye drops with preservatives can promote inflammation, it is better to choose preservative free artificial tear drops and lubricating eye drops.
[7]
Bandage silicone hydrogel or scleral
contact lens
may be used to protect cornea.
[3]
But, risk of infection is more with bandage contact lens use.
[7]
Moisture
goggles
may also be used to protect cornea.
[9]
Temporary or permanent tarsorrhaphy may be indicated to treat lagophthalmos. Gold weights can be inserted into the upper eyelid to treat fasial nerve palsy.
[9]
Treatment
[
edit
]
Treatment of the cause of the exposure is to be done first. For example, in proptosis due to thyroid eye disease, regulation of thyroid hormone levels may be advised. Symblepharon can be treated surgically. If necessary, management of proptosis may be done by orbital decompression.
[3]
Eyelid taping during sleep may alleviate mild cases of exposure keratopathy.
[3]
If
corneal ulcer
is detected, it may be treated medically with
antibiotics
. If corneal perforation has occurred, immediate treatment measures should be done to restore the integrity of perforated cornea. Tissue adhesive glues, covering with conjunctival flap, bandage
soft contact lens
or therapeutic
keratoplasty
may be indicated to treat perforated corneal ulcer.
See also
[
edit
]
References
[
edit
]
- ^
Zasloff, Michael (1 October 2012).
"Defending the cornea with antibacterial fragments of keratin"
.
The Journal of Clinical Investigation
.
122
(10): 3471?3473.
doi
:
10.1172/JCI65380
.
ISSN
0021-9738
.
PMC
3461931
.
PMID
23006322
.
- ^
McDermott, Alison M. (December 2013).
"Antimicrobial Compounds in Tears"
.
Experimental Eye Research
.
117
: 53?61.
doi
:
10.1016/j.exer.2013.07.014
.
ISSN
0014-4835
.
PMC
3844110
.
PMID
23880529
.
- ^
a
b
c
d
e
f
g
h
i
John F., Salmon (2020). "Cornea".
Kanski's clinical ophthalmology : a systematic approach
(9th ed.). Edinburgh: Elsevier. p. 242.
ISBN
978-0-7020-7713-5
.
OCLC
1131846767
.
- ^
Tsai, Shawn H.; Yeh, Shu-I; Chen, Lee-Jen; Wu, Chien-Hsiu; Liao, Shu-Lang (1 June 2009). "Nocturnal Lagophthalmos".
International Journal of Gerontology
.
3
(2): 89?95.
doi
:
10.1016/S1873-9598(09)70027-4
.
ISSN
1873-9598
.
- ^
Bahn, Rebecca S. (2010).
"Graves' Ophthalmopathy"
.
New England Journal of Medicine
.
362
(8): 726?38.
doi
:
10.1056/NEJMra0905750
.
PMC
3902010
.
PMID
20181974
.
- ^
Goldman, Lee (2012).
Goldman's Cecil Medicine
(24th ed.). Philadelphia: Elsevier Saunders. pp.
2430
.
ISBN
978-1437727883
.
- ^
a
b
c
"Exposure Keratopathy - EyeWiki"
.
eyewiki.aao.org
.
- ^
Mathenge, Wanjiku (2018).
"Emergency management: exposure keratopathy"
.
Community Eye Health
.
31
(103): 69.
ISSN
0953-6833
.
PMC
6253321
.
PMID
30487689
.
- ^
a
b
"Lagophthalmos Evaluation and Treatment"
.
American Academy of Ophthalmology
. 1 April 2008.