Keratopathy

What is Keratopathy?

Keratopathy refers to a disease affecting the cornea, which is the clear front surface of your eye. Different types of keratopathy are associated with various clinical situations. Some keratopathies may be caused by local factors, while others may indicate broader systemic issues. Knowing what causes the keratopathy and how it develops can help us decide the best treatment. This explanation covers some of the most common types of keratopathy.

What Causes Keratopathy?

Band shaped keratopathy (BSK) is a type of eye inflammation caused by ongoing issues like uveitis (inflammation inside the eye), long-term exposure to silicone oil in the eye, or chronic herpetic keratouveitis (inflammation of the cornea and the uvea of the eye caused by the herpes virus). It could also be associated with various systemic conditions such as overactive parathyroid glands, vitamin D poisoning, or multiple myeloma (a type of blood cancer), to name a few.

Pseudophakic and aphakic bullous keratopathy (PBK and ABK) are conditions where damage to the innermost layer of cells in your cornea causes it to swell up, blurring vision. This can happen due to damage caused during eye surgery, exposure to toxic solutions, or a sudden increase in pressure within the eye. In ABK, contact between the clear gel that fills your eyeball (the vitreous) and the cornea may cause cell death leading to this condition.

Striate keratopathy could happen if there’s swelling (edema) of the cornea after cataract surgery, even if the cornea was previously healthy. It typically clears up over a few days with the help of medication. This condition can result from excessive energy during the process to break up and remove a cataract or if toxic substances enter the eye during surgery.

Whorl keratopathy results from either certain medications or non-drug related conditions such as Fabry’s disease (a rare genetic disorder), or after certain kinds of eye surgery.

Exposure keratopathy is when the tear film – that lubricates and protects your eye – doesn’t spread evenly over the surface of your eye. This can be the result of decreased blinking, issues with the eyelids that cause poor coverage, among others. This uneven spread can harm the outer layer of your eye.

Infectious crystalline keratopathy (ICK) is a rare condition where there is a gray-white branching cloudiness in the corneal stroma (middle layer of the cornea), typically seen in cases with long-term use of topical steroid and post-corneal transplant. This is mainly triggered by Streptococcus viridians, a type of bacteria.

Neurotrophic keratopathy may happen after herpes zoster opthalmicus (a shingles infection in your eye) or damage to the trigeminal nerve (the nerve that senses touch, pain, and temperature in your face) caused by surgery or tumors.

Metabolic Keratopathy happens due to a fault in the normal function of enzymes, causing harmful byproducts to build up in the body, including the cornea. This could be due to conditions like mucopolysaccharidoses, cystinosis, Wilson’s disease, or lecithin-cholesterol acyltransferase deficiency.

Filamentary keratopathy is a long-term disorder where filaments consisting of mucus and epithelial debris (a type of cell) stick to the corneal surface. This could be due to a variety of conditions or the use of specific medications.

Climatic droplet keratopathy, Labrador keratopathy, or Spheroidal degeneration are conditions that result from the photochemical degradation (breaking down of chemicals by light) of plasma proteins by UV light. Lipid keratopathy is a degenerative condition of the cornea where lipid degradation (breaking down of fats) occurs.

Superficial punctate keratopathy (SPK) happens when the eye’s epithelial cells (surface cells of the eye) are lost. This could be due to viral infections, injury from chemicals, contact lens wear, or ultraviolet ray exposure, among others.

Ultraviolet (UV) keratopathy is a condition caused by a burn on the cornea from UV-B rays. This can happen due to exposure to a welding arc or light reflected from the snow.

Toxic keratopathy may take place due to exposure to polyquaternium-1, a preservative used in some eye drop solutions.

Keratopathy linked to vernal keratoconjunctivitis (VKC) is likely due to the release of various proteins that trigger inflammation.

Keratopathy related to Stevens-Johnson syndrome (SJS)/ toxic epidermal necrolysis (TEN): These are severe skin reactions, often triggered by a reaction to medication. It can sometimes also be caused by a viral fever.

Keratopathy associated with aniridia (a rare genetic disorder where the iris of the eye is completely or partially absent) is most likely due to a deficiency in limbal stem cells (these cells help repair damage to the cornea).

Risk Factors and Frequency for Keratopathy

Studies have been conducted looking at different types of keratopathy (a term for disease affecting the cornea of the eye) in various patient groups.

• In a research study on end-stage kidney disease patients, about 0.14% of them were found to have a form of keratopathy known as band-shaped keratopathy.
• Bullous keratopathy, another form, is found in around 1% to 2% of patients who undergo cataract surgery. This translates to almost 2 to 4 million patients worldwide.
• In an investigation of 30 cases of keratitis (inflammation of the cornea) following a cornea transplant procedure, 5 cases of a specific type of infection known as infectious crystalline keratopathy were found.
• Harmful health conditions known as SJS and TEN can lead to chronic complications in the eyes in 43-89% of cases. Keratopathy is a frequent issue seen in these cases.
• In a separate study, it was found that 89% of eyes with a condition known as aniridic (absence of the iris in the eye) had keratopathy.

Signs and Symptoms of Keratopathy

Band-shaped keratopathy is a condition often caused by chronic uveitis, vitreoretinal surgery, or specific systemic diseases. Symptoms include reduced vision, feeling of a foreign body in the eye, and physical changes in the eye’s appearance. Notably, an exam shows a greyish white lesion in their eye that looks like a band and a swiss-cheese pattern.

PBK and ABK usually follow complex cataract surgery. People with these conditions may experience slow visual recovery after surgery or sudden vision loss after a period of relatively good vision. An examination would show corneal swelling and blisters, as well as folds in the eye’s innermost layer. In long-term cases, subepithelial scarring, epithelium thickening, and vascularization may occur obstructing the view of the anterior chamber.

For striate keratopathy, you may have experienced long or complicated eye surgeries. It is characterized by corneal stromal edema and folds in Descemet’s membrane, which make the cornea appear less clear.

Whorl keratopathy is diagnosed when a slit-lamp exam reveals golden brown spots on basal epithelial cells arranged in a whorl-like pattern. This typically arises due to the prolonged use of certain medications.

• Exposure keratopathy can follow parotid gland surgery or prolonged bed rest. Visible changes include thinning eyelashes, eyelid malformations, and bulging eyes. There may also be an infection and inflammation in the cornea.
• Infectious crystalline keratopathy is often linked to a history of penetrating keratoplasty and extended use of topical steroids. Symptoms start with mild discomfort many years after the operation and vision impairment.
• Neurotrophic keratopathy generally happens after significant loss of corneal sensation, leading to chronic corneal erosions. As a result, stromal ulcerations may occur.
• Metabolic keratopathies are congenital and bilateral. They’re usually linked to organ dysfunctions. These result in a cloudy cornea due to substance deposits in the cornea, photophobia, and blepharospasm.
• People with filamentary keratopathy often experience sensations of a foreign body in the eye, blurred vision, excessive tearing, frequent blinking, photophobia, and blepharospasm. Corneal filaments and redness are common findings on a clinical examination.
• Climatic droplet keratopathy is caused by prolonged exposure to sunlight. The symptoms include sensation of foreign bodies and watering of the eyes. If the central cornea is involved, it may lead to decreased visual acuity.
• Lipid keratopathy is marked by a gradual decline in vision and is often associated with viral keratitis. Clinical examination often reveals lipid deposits in the cornea.
• Superficial punctate keratopathy and vernal keratoconjunctivitis related keratopathy are often associated with contact lens wear. Symptoms include pain, sensitivity to light, and eye redness. Physical examination typically reveals small rough spots on the cornea.
• Ultraviolet keratopathy is linked to exposure to UV radiation, such as from looking at a welder’s torch or being in snow-capped terrains. Physical exams usually reveal small rough spots on the cornea.
• Keratopathy related to SJS/TEN may show changes like keratinization of lid margins, conjunctival scarring, and conjunctivalization of the cornea.
• Keratopathy related to aniridia results in abnormal epithelium leading to thickening of the epithelium, and conjunctivalization. The physical examination may also reveal a peripheral pannus.

Testing for Keratopathy

Band shaped keratopathy is often diagnosed by a clinical eye test using a device called a slit-lamp. This test reveals a certain look and location of the damage. To understand what might be causing this issue, a variety of blood tests are performed, including tests for calcium, parathormone, and vitamin D levels, among others. Other tests such as a urine analysis and chest x-ray might also be done to check for systemic causes.

For PBK and ABK, the diagnosis is often based on the patient’s history, especially if they’ve had complicated eye surgery or slow visual recovery. Sometimes, the cornea is covered in a thick layer that prevents the doctor from fully examining the eye. A test called Anterior Segment Optical Coherence Tomography (ASOCT) is very important here. It measures the thickness of the cornea and the extent of scarring, among other things. It’s also crucial to examine the cells and their shape in the other eye.

Striate keratopathy can be differentiated from other conditions by a slit-lamp examination. Again, an ASOCT might be done to confirm the result.

Whorl keratopathy can be diagnosed through a slit-lamp examination which shows specific deposits in the eye. If no medications are causing these deposits, other medical tests may be done to rule out any related systemic diseases.

Exposure keratopathy is typically diagnosed through clinical examination. A doctor would look for the specific cause and check for any physical abnormalities like muscle tone, eye lid abnormalities, or other signs that can indicate an underlying issue.

Infectious crystalline keratopathy is usually diagnosed through a clinical examination and taking the patient’s history into account. Occasionally, a tissue biopsy may be done to identify the organism causing the issue.

Neurotrophic keratopathy is usually diagnosed based on the patient’s history and certain clinical findings.

Metabolic keratopathy is often indicated by the symptoms affecting both eyes and associated general body symptoms. Depending on the specific type, various diagnostic tests, from enzyme assays to urine collection, might be required.

Filamentary keratopathy is usually diagnosed based on the clinical symptoms and extensive blood tests may be done to look for systemic causes.

Climatic droplet keratopathy and Lipid keratopathy are usually diagnosed based on a clinical exam.

Superficial punctate keratopathy and ultraviolet keratopathy are usually diagnosed through a test where a dye is used and the eyes viewed under a special light to identify areas of damage. The pattern of these damaged areas could suggest the cause of the problem.

Keratopathy related to SJS/TEN is often diagnosed through specific tests and changes observed using a special dye and light.

Keratopathy related to aniridia is usually diagnosed through clinical examination.

Treatment Options for Keratopathy

For band-shaped keratopathy, the main treatment is surgical removal. It’s crucial, though, that any local or systemic conditions contributing to the keratopathy are under control before surgery. If surgery is not a suitable option, colored contact lenses may be recommended. In some cases, there could be a recurrence of the keratopathy if the primary condition causing it is not effectively controlled.

PBK and ABK are consequences of the loss of endothelial cells during cataract surgery. To treat these conditions, healthy cells from a donor’s cornea are transplanted. In more complicated cases, a full-thickness tissue transplants may be needed. It’s worth mentioning that some procedures could help relieve symptoms for patients with vision loss due to severe nerve damage.

Meanwhile, striate keratopathy is mainly treated with topical steroids. The dosage of these steroids depends on the severity of the condition, with additional treatments like hypertonic saline drops or ointments added as requiring.

Whorl keratopathy usually doesn’t impact one’s vision and thus does not need treatment. If the condition was caused by certain medications, discontinuation of these drugs will usually lead to resolution.

Exposure keratopathy, which can occur with conditions like Bell’s palsy, is typically managed by instilling artificial tears frequently, lubricating the eyes with a gel, and taping the eyes closed at night. In more severe cases addressing the root cause of the issue, such as a thyroid condition, or surgery may be necessary.

Similarly, infectious crystalline keratopathy can be tricky to treat with medications due to resistance, often requiring a redo of the corneal graft procedure. Neurotrophic keratopathy and metabolic keratopathy also often require specialized treatments such as transplant or specific medical solutions.

The treatment of filamentary keratopathy involves addressing the underlying dry eye condition, while treatments for climatic droplet keratopathy and lipid keratopathy vary according to the severity of the condition and can include procedures ranging from superficial keratectomy to penetrating keratoplasty.

For conditions like superficial punctate keratopathy and ultraviolet keratopathy, lubricants are key to treatment. Any causes, like contact lenses or certain papillae, should be avoided or treated in addition to using lubricants. Keratopathy related to both VKC and SJS/TEN can be addressed by managing the underlying ocular anomalies with special medication or procedures. Finally, keratopathy related to aniridia is usually treated with limbal stem cell transplantation followed by a full-thickness tissue transplant.

What else can Keratopathy be?

When doctors are diagnosing different types of keratopathies, or diseases of the cornea, there are several other conditions they need to consider as well. These are known as differential diagnoses, and considering them helps to ensure an accurate diagnosis is made. Here are some of those situations:

• For Band shaped keratopathy (BSK), Spheroidal degeneration and Salzmann nodular degeneration are key alternate diagnoses.
• In case of PBK and ABK, one possible other condition might be corneal decompensation due to Fuchs’ endothelial dystrophy.
• When diagnosing Striate keratopathy, it could actually be corneal edema caused by detachment of Descemet’s membrane.
• Iron lines in the eyes can be a major alternate diagnosis when considering Whorl keratopathy.
• In case of Exposure keratopathy, an inferiorly located corneal ulcer could be the true condition.
• When diagnosing Infectious crystalline keratopathy (ICK), it could be mistaken for several other conditions such as bacterial, fungal or viral keratitis, among others.
• In Metabolic keratopathy, it can sometimes resemble bilateral and diffuse corneal dystrophies. Arcus can be a differential diagnosis for the KF ring.
• When looking at Filamentary keratopathy, mucus debris on the ocular surface could be the real issue.
• Climatic droplet keratopathy could be misdiagnosed as fine variants of spheroidal degeneration or microcystic corneal edema.
• In diagnosing Lipid keratopathy, interstitial keratitis should be considered as a possible other condition.
• For Superficial punctate keratopathy (SPK), it could be confused with microsporidial keratoconjunctivitis and Thygeson’s punctate keratopathy.
• Atopic keratoconjunctivitis can often be mistaken for VKC related keratopathy.
• In diagnosing keratopathy related to SJS/TEN, it could be confused with Mycoplasma induced rash and mucositis, or erythema multiforme.

It’s clear that a careful examination is crucial for making an accurate diagnosis, as many other diseases can mimic the symptoms of keratopathies.

What to expect with Keratopathy

Band-shaped keratopathy (BSK) is a type of eye damage that typically develops in eyes with long-term inflammation. This condition can impact your vision and change the appearance of your eye.

If you have pseudophakic and aphakic bullous keratopathy, which are complex medical terms for certain types of eye injuries, your cornea (the clear front surface of your eye) might not function properly. Endothelial keratoplasty, which is a type of corneal transplant, is a treatment option. However, if the condition is not treated quickly enough, it can result in scarring and pannus development, which is a growth of fine blood vessels on the eye.

Striate keratopathy is another type of eye damage that generally clears up within 3 to 4 weeks with the help of steroid eye drops.

Whorl keratopathy does not usually affect your vision. It goes away once you stop using the medication that caused it.

Exposure keratopathy can start with a damaged epithelium, which is the clear layer at the front of your eye. If left untreated, the condition worsens, the cornea can melt away and potentially perforate. In severe cases, there’s a high risk of bacterial infection.

Infectious crystalline keratopathy (ICK) is difficult to treat with medication and often requires a corneal transplant to restore vision.

With metabolic keratopathy, untreated MPS (a buildup of certain chemicals in the body) can cause the entire cornea to become opaque. In some severe cases, untreated MPS can even be fatal. Wilson’s disease can also cause a ring in the cornea that doesn’t affect vision, but its impact on the body could potentially be lethal.

Filamentary keratopathy, another type of eye condition, is usually controlled with treatment. However, repeat cases may indicate a broader health problem that needs to be identified and managed.

Climatic droplet keratopathy, an eye condition typically linked with prolonged sunlight exposure, tends to worsen if sun-related eye damage continues.

Superficial punctate keratopathy is an eye condition that can often improve once causes such as contact lenses or giant papillae (an inflammation in the eye) have been addressed.

In the case of keratopathy related to SJS/TEN, or Stevens-Johnson syndrome / toxic epidermal necrolysis, the final stage often results in severe dry eyes and a damaged ocular surface, where your eye’s outer layer loses its usual characteristics and starts looking and behaving like skin.

Possible Complications When Diagnosed with Keratopathy

In simpler terms:

• Band-shaped keratopathy: The main issues are visual impairment and cosmetic disfigurement.
• Pseudophakic and aphakic bullous keratopathy: This is identified by a thick, blood vessel-rich skin growth over a swollen cornea leading to loss of transparency. The risk of keratitis, a form of cornea inflammation caused by an infection, is a significant concern.
• Striate keratopathy: This type is worrisome because of the delayed or even non-existent recovery depending on the damage caused to the endothelium, the inner lining of the cornea.
• Whorl keratopathy: While not problematic on its own, it may indicate the presence of diseases like Fabry’s, a genetic disorder.
• Exposure keratopathy: This form brings the risk of corneal ulcers and spontenous expulsion of the eye contents
• Infectious crystalline keratopathy: It presents a risk of a hidden infection suddenly becoming worse.
• Metabolic keratopathy: If left untreated, this can lead to a foggy cornea in cases of MPS (Mucopolysaccharidosis).
• Filamentary keratopathy: There is a higher risk of microbial keratitis, particularly if a bandage contact lens is used.
• Climatic droplet keratopathy: This increases the susceptibility to microbial keratitis.
• Vernal keratoconjunctivitis (VKC) related keratopathy: Shield ulcer and keratoconus (a condition where the cornea thins and bulges into a conelike shape) are the known complications.
• Steven-Johnson syndrome/Toxic Epidermal Necrolysis (SJS/TEN) related keratopathy: The complications include microbial keratitis and corneal melting.

Preventing Keratopathy

If you have any issues with your cornea – that’s the clear, dome-shaped surface at the front of your eye – it’s crucial to seek help from a trained eye specialist, known as an ophthalmologist. Please avoid using home remedies to treat these issues as they may lead to further complications.