Recurrent corneal erosion
Encyclopedia
Recurrent corneal erosion is a disorder of the eye
s characterized by the failure of the cornea
's outermost layer of epithelial cells to attach to the underlying basement membrane
(Bowman's layer). The condition is excruciatingly painful because the loss of these cells results in the exposure of sensitive corneal nerves.
or ulcer
), but also may be due to corneal dystrophy
or corneal disease. In other words, one may suffer from corneal erosions as a result of another disorder, such as map dot fingerprint disease
.
(i.e. sensitivity to bright lights), and tearing often at the time of awakening or during sleep when the eyelids are rubbed or opened. Signs of the condition include corneal abrasion or localized roughening of the corneal epithelium, sometimes with map-like lines, epithelial dots or microcyts, or fingerprint patterns.
stain must be applied first and a blue-light used. Opticians, optometrists and ophthalmologists have use of slit lamp microscopes that allow for more thorough evaluation under the higher magnification. Mis-diagnosis of a scratched cornea is fairly common, especially in younger patients.
s) and so artificial tears (eg viscotears) are applied frequently.
Whilst individual episodes may settle within a few hours or days, additional episodes (as the name suggests) will recur at intervals.
Environmental:
General personal measures:
Pre-bed routine:
Waking options:
use of therapeutic contact lens
, controlled puncturing of the surface layer of the eye (Anterior Stromal Puncture) and laser phototherapeutic keratectomy
(PTK). These all essentially try to allow the surface epithelium to reestablish with normal binding to the underlying basement membrane
, the method chosen depends upon the location & size of the erosion.
The use of contact lenses may help prevent the abrasion during blinking lifting off the surface layer and uses thin lenses that are gas permeable to minimise reduced oxygenation. However they need to be used for between 8–26 weeks and such persistent use both incurs frequent follow-up visits and may increase the risk of infections.
Alternatively, under local anaesthetic, the corneal layer may be gently removed with a fine needle, cauterised (heat or laser) or 'spot welding' attempted (again with lasers). The procedures are not guaranteed to work, and in a minority may exacerbate the problem.
Anterior Stromal Puncture with a 20-25 gauge needle is an effective and simple treatment.
An option for minimally invasive and long-term effective therapy is laser phototherapeutic keratectomy
. Laser PTK involves the surgical laser treatment of the cornea to selectively ablate cells on the surface layer of the cornea. It is thought that the natural regrowth of cells in the following days are better able to attach to the basement membrane to prevent recurrence of the condition. Laser PTK has been found to be most effective after epithelial debridement for the partial ablation of Bowman's lamella, which performed prior to PTK in the surgical procedure. This is meant to smoothen out the corneal area that the laser PTK will then treat. In some cases, small-spot PTK, which only treats certain areas of the cornea may also be an acceptable alternative.
(MMP) enzymes.
These enzymes dissolve the basement membrane
and fibrils of the hemidesmosomes, which can lead to the separation of the epithelial layer.
Treatment with oral tetracycline antibiotics
(such as doxycycline
or oxytetracycline
) together with a topical corticosteroid
(such as prednisolone
), reduce MMP activity and may rapidly resolve and prevent further episodes in cases unresponsive to conventional therapies. Some have now proposed this as the first line therapy after lubricants have failed.
Human eye
The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...
s characterized by the failure of the cornea
Cornea
The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Together with the lens, the cornea refracts light, with the cornea accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is...
's outermost layer of epithelial cells to attach to the underlying basement membrane
Basement membrane
The basement membrane is a thin sheet of fibers that underlies the epithelium, which lines the cavities and surfaces of organs including skin, or the endothelium, which lines the interior surface of blood vessels.- Composition :...
(Bowman's layer). The condition is excruciatingly painful because the loss of these cells results in the exposure of sensitive corneal nerves.
Etiology
There is often a history of previous corneal injury (corneal abrasionCorneal abrasion
Corneal abrasion is a medical condition involving the loss of the surface epithelial layer of the eye's cornea.-Symptoms and signs:Symptoms of corneal abrasion include pain, photophobia, a foreign-body sensation, excessive squinting, and a reflex production of tears...
or ulcer
Corneal ulcer
A corneal ulcer, or ulcerative keratitis, is an inflammatory condition of the cornea involving loss of its outer layer. It is very common in dogs and is sometimes seen in cats...
), but also may be due to corneal dystrophy
Corneal dystrophy
Corneal dystrophy is a group of disorders, characterised by a noninflammatory, inherited, bilateral opacity of the transparent front part of the eye called the cornea.The distrophies could be subdivided based on specie affected:...
or corneal disease. In other words, one may suffer from corneal erosions as a result of another disorder, such as map dot fingerprint disease
Epithelial basement membrane dystrophy
Epithelial basement membrane dystrophy is a disorder of the eye, sometimes included in the group of corneal dystrophies. It diverges from the formal definition of corneal dystrophy in being in most cases non-familial...
.
Symptoms and signs
Symptoms include recurring attacks of severe acute ocular pain, foreign-body sensation, photophobiaPhotophobia
Photophobia is a symptom of abnormal intolerance to visual perception of light. As a medical symptom photophobia is not a morbid fear or phobia, but an experience of discomfort or pain to the eyes due to light exposure or by presence of actual physical photosensitivity of the eyes, though the term...
(i.e. sensitivity to bright lights), and tearing often at the time of awakening or during sleep when the eyelids are rubbed or opened. Signs of the condition include corneal abrasion or localized roughening of the corneal epithelium, sometimes with map-like lines, epithelial dots or microcyts, or fingerprint patterns.
Diagnosis
The erosion may be seen by a doctor using the magnification of an ophthalmoscope, although usually fluoresceinFluorescein
Fluorescein is a synthetic organic compound available as a dark orange/red powder soluble in water and alcohol. It is widely used as a fluorescent tracer for many applications....
stain must be applied first and a blue-light used. Opticians, optometrists and ophthalmologists have use of slit lamp microscopes that allow for more thorough evaluation under the higher magnification. Mis-diagnosis of a scratched cornea is fairly common, especially in younger patients.
Management of episodes
With the eye generally profusely watering, the type of tears being produced have little adhesive property. Water or saline eye drops tend therefore to be ineffective. Rather a 'better quality' of tear is required with higher 'wetting ability' (ie greater amount of glycoproteinGlycoprotein
Glycoproteins are proteins that contain oligosaccharide chains covalently attached to polypeptide side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. In proteins that have segments extending...
s) and so artificial tears (eg viscotears) are applied frequently.
Whilst individual episodes may settle within a few hours or days, additional episodes (as the name suggests) will recur at intervals.
Prevention
Given that episodes tend to occur on awakening and managed by use of good 'wetting agents', approaches to be taken to help prevent episodes include:Environmental:
- ensuring that the air is humidified rather than dry, not overheated and without excessive airflow over the face. Also avoiding irritants such as cigarette smoke.
- use of protective glasses especially when gardening or playing with children.
General personal measures:
- maintaining general hydration levels with adequate fluid intake and reducing evening alcohol consumption (so preventing "Drinker's Eye").
- not sleeping-in late as the cornea tends to dry out the longer the eyelids are closed.
Pre-bed routine:
- routine use of long-lasting eye ointments (e.g. lacrilube/Polyvisc) applied before going to bed.
- occasional use of the anti-inflammatory eyedrop FML (prescribed by an opthamologist or optometrist) before going to bed if the affected eye feels inflamed, dry or gritty
Waking options:
- learn to wake with eyes closed and still and keeping artificial tear drops within reach so that they may be squirted under the inner corner of the eyelids if the eyes feel uncomfortable upon waking.
- It has also been suggested that the eyelids should be rubbed gently, or pulled slowly open with your fingers, before trying to open them, or keeping the affected eye closed while "looking" left and right to help spread lubricating tears. If the patient's eyelids feel stuck to the cornea on waking and no intense pain is present, use a fingertip to press firmly on the eyelid to push the eye's natural lubricants onto the affected area. This procedure frees the eyelid from the cornea and prevents tearing of the cornea.
Treatment
Where episodes frequently occur, or there is an underlying disorder, one medical, or three types of surgical curative procedures may be attempted:use of therapeutic contact lens
Contact lens
A contact lens, or simply contact, is a lens placed on the eye. They are considered medical devices and can be worn to correct vision, for cosmetic or therapeutic reasons. In 2004, it was estimated that 125 million people use contact lenses worldwide, including 28 to 38 million in the United...
, controlled puncturing of the surface layer of the eye (Anterior Stromal Puncture) and laser phototherapeutic keratectomy
Phototherapeutic keratectomy
Phototherapeutic keratectomy is a type of eye surgery that uses a laser to treat various ocular disorders by removing tissue from the cornea. PTK allows the removal of superficial corneal opacities and surface irregularities...
(PTK). These all essentially try to allow the surface epithelium to reestablish with normal binding to the underlying basement membrane
Basement membrane
The basement membrane is a thin sheet of fibers that underlies the epithelium, which lines the cavities and surfaces of organs including skin, or the endothelium, which lines the interior surface of blood vessels.- Composition :...
, the method chosen depends upon the location & size of the erosion.
Surgical
A punctal plug may be inserted into the tear duct by an optometrist or ophthalmologist, decreasing the removal of natural tears from the affected eye.The use of contact lenses may help prevent the abrasion during blinking lifting off the surface layer and uses thin lenses that are gas permeable to minimise reduced oxygenation. However they need to be used for between 8–26 weeks and such persistent use both incurs frequent follow-up visits and may increase the risk of infections.
Alternatively, under local anaesthetic, the corneal layer may be gently removed with a fine needle, cauterised (heat or laser) or 'spot welding' attempted (again with lasers). The procedures are not guaranteed to work, and in a minority may exacerbate the problem.
Anterior Stromal Puncture with a 20-25 gauge needle is an effective and simple treatment.
An option for minimally invasive and long-term effective therapy is laser phototherapeutic keratectomy
Phototherapeutic keratectomy
Phototherapeutic keratectomy is a type of eye surgery that uses a laser to treat various ocular disorders by removing tissue from the cornea. PTK allows the removal of superficial corneal opacities and surface irregularities...
. Laser PTK involves the surgical laser treatment of the cornea to selectively ablate cells on the surface layer of the cornea. It is thought that the natural regrowth of cells in the following days are better able to attach to the basement membrane to prevent recurrence of the condition. Laser PTK has been found to be most effective after epithelial debridement for the partial ablation of Bowman's lamella, which performed prior to PTK in the surgical procedure. This is meant to smoothen out the corneal area that the laser PTK will then treat. In some cases, small-spot PTK, which only treats certain areas of the cornea may also be an acceptable alternative.
Medical
Patients with recalcitrant recurrent corneal erosions often show increased levels of matrix metalloproteinaseMatrix metalloproteinase
Matrix metalloproteinases are zinc-dependent endopeptidases; other family members are adamalysins, serralysins, and astacins. The MMPs belong to a larger family of proteases known as the metzincin superfamily....
(MMP) enzymes.
These enzymes dissolve the basement membrane
Basement membrane
The basement membrane is a thin sheet of fibers that underlies the epithelium, which lines the cavities and surfaces of organs including skin, or the endothelium, which lines the interior surface of blood vessels.- Composition :...
and fibrils of the hemidesmosomes, which can lead to the separation of the epithelial layer.
Treatment with oral tetracycline antibiotics
Tetracycline antibiotics
Tetracyclines are a group of broad-spectrum antibiotics whose general usefulness has been reduced with the onset of bacterial resistance. Despite this, they remain the treatment of choice for some specific indications....
(such as doxycycline
Doxycycline
Doxycycline INN is a member of the tetracycline antibiotics group, and is commonly used to treat a variety of infections. Doxycycline is a semisynthetic tetracycline invented and clinically developed in the early 1960s by Pfizer Inc. and marketed under the brand name Vibramycin. Vibramycin...
or oxytetracycline
Oxytetracycline
Oxytetracycline was the second of the broad-spectrum tetracycline group of antibiotics to be discovered.Oxytetracycline works by interfering with the ability of bacteria to produce proteins that are essential to them. Without these proteins the bacteria cannot grow, multiply and increase in numbers...
) together with a topical corticosteroid
Corticosteroid
Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex. Corticosteroids are involved in a wide range of physiologic systems such as stress response, immune response and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte...
(such as prednisolone
Prednisolone
Prednisolone is the active metabolite of prednisone, which is also used as a drug.-Uses:Prednisolone is a corticosteroid drug with predominant glucocorticoid and low mineralocorticoid activity, making it useful for the treatment of a wide range of inflammatory and auto-immune conditions such as...
), reduce MMP activity and may rapidly resolve and prevent further episodes in cases unresponsive to conventional therapies. Some have now proposed this as the first line therapy after lubricants have failed.
See also
- Dystrophia Helsinglandica
- Dystrophia Smolandiensis
- Corneal ulcers in dogs
External links
- Facts About the Cornea and Corneal Disease The National Eye Institute (NEI)
- St Lukes eye centre information
- UK Patient associate site for eye disorders, www.Cataract-Doctor.com