Diffuse lamellar keratitis (DLK) is a
sterile inflammation
Inflammation (from la, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants, and is a protective response involving immune cells, blood vessels, and molec ...
of the
cornea
The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Along with the anterior chamber and lens, the cornea refracts light, accounting for approximately two-thirds of the eye's total optical ...
which may occur after
refractive surgery, such as
LASIK
LASIK or Lasik (''laser-assisted in situ keratomileusis''), commonly referred to as laser eye surgery or laser vision correction, is a type of refractive surgery for the correction of myopia, hyperopia, and an actual cure for astigmatism, sinc ...
. Its incidence has been estimated to be 1 in 500 patients, though this may be as high as 32% in some cases.
Signs and symptoms
Patients typically present within one week of surgery with eye pain,
photophobia
Photophobia is a medical 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 ...
,
conjunctivitis
Conjunctivitis, also known as pink eye, is inflammation of the outermost layer of the white part of the eye and the inner surface of the eyelid. It makes the eye appear pink or reddish. Pain, burning, scratchiness, or itchiness may occur. The ...
, or excessive tear production.
Risk factors
DLK is predominantly associated with Lasik, as the creation of a flap creates a potential space for cells to accumulate. Individuals with
atopic conditions with pre-existing
allergic conjunctivitis
Allergic conjunctivitis (AC) is inflammation of the conjunctiva (the membrane covering the white part of the eye) due to allergy. Although allergens differ among patients, the most common cause is hay fever. Symptoms consist of redness (mainly due ...
, or
ocular rosacea
Ocular rosacea is a manifestation of rosacea that affects the eyes and eyelids. Signs and symptoms generally consist of redness, irritation or burning of the eyes. Affected individuals may also feel that there is something, such as an eyelash, i ...
, are more prone to developing the condition after surgery. Some authors have reported that moderate to severe eye allergies and chronic allergic conjunctivitis are an absolute contraindication to the LASIK procedure. This is in distinction to findings of earlier studies. Keratitis can also occur after
photorefractive keratectomy
Photorefractive keratectomy (PRK) and laser-assisted sub-epithelial keratectomy (or laser epithelial keratomileusis) (LASEK) are laser eye surgery procedures intended to correct a person's vision, reducing dependency on glasses or contact lense ...
(PRK), although because it occurs in the setting of infection, it is distinct from the sterile
infiltrates of DLK. DLK can also occur following
myopic
Near-sightedness, also known as myopia and short-sightedness, is an eye disease where light focuses in front of, instead of on, the retina. As a result, distant objects appear blurry while close objects appear normal. Other symptoms may include ...
keratomileusis, in which a disc of corneal tissue is removed, shaped and sutured back into place, although this technique is more historical, having been replaced by Lasik and PRK.
Pathology
DLK is usually seen after refractive surgery.
Neutrophils infiltrate the corneal
stroma in a diffuse, multifocal pattern. Infiltration is confined to the surgical flap interface with no posterior or anterior extension, and overlying epithelium most often remains intact. As it is a sterile process, cultures based on swab tests are negative.
Diagnosis
Stages
There are 4 stages of disease, with stage 4 being the rarest and most severe.
* Stage 1 Cells infiltrate the periphery of the flap, without involving central cornea.
* Stage 2 Peripheral cells migrate to the center of the cornea, and impair vision; presentation is usually 2 to 3 days after surgery.
* Stage 3 Cells at the central cornea form clumps of dense cell aggregates.
* Stage 4 Otherwise known as central toxic keratopathy, stage 4 characteristically has no inflammatory cells at the anterior chamber or cornea, but there is central stromal necrosis, and the cornea becomes opacified; onset is usually 3 to 9 days after refractive surgery.
Treatment
Depending on severity, therapies may range from topical or oral anti-inflammatories to irrigation and surgical repair.
References
External links
{{DEFAULTSORT:Diffuse Lamellar Keratitis
Eye diseases