- • Cornea is the first coat of the eye which is transparent circular structure in front of the eye.
- • Functionally it acts as a lens responsible for focusing rays inside the eye. It is an important optical structure through which rays of light enter the eye. Any damage or injury to this delicate structure can lead to permanent loss of corneal transparency or causes clouding and opacification.
- • Loss of corneal transparency prevents the entry of light rays into the eye and reduces the vision. In cases of severe damage, this can cause total loss of vision making the person visually handicapped.
- • There are many conditions like malnutrition, Vitamin A deficiency, infection, certain corneal diseases such as ‘keratoconus’ and ‘corneal degeneration’, which can cause corneal blindness.
Common Corneal problems includes:
3) Corneal dystrophies,
4) Corneal edema.
5) Corneal tears,
6) Corneal ulcers, infective keraitis, contact lens related keratitis, allergic keratoconjunctivitis
Pterygium is a veil like lesion that usually occurs in exposed part of white of the eye. This grows slowly over the cornea (the central black portion) and can obstruct vision or deteriorate vision by inducing cylindrical power in the eye.
Signs / Symptoms:
- Gritty feeling
- Sensation of a foreign body in the eye
- Blurred vision
- Prolonged exposure to ultraviolet light
- Dry eye
- Irritants such as dust and wind
Pterygium is not only cosmetically disfiguring but can affect the vision as well. In view of this it is advisable to surgically excise it at the earliest. Surgical excision of pterygium is a simple day care procedure with no adverse effects.
Latest surgical method involves removing the pterygium and placing a healthy tissue/graft on bare area which prevents recurrence with the help of surgical glue or stiches. It is cosmetically very rewarding. Surgery for pterygium is minimally invasive, sutureless and is very safe.
Pterygium does not respond to medical treatment and surgical excision is the treatment of choice.
It is a progressive disease of the outer transparent layer of the eye (cornea) affecting young adults. It is characterized by progressive thinning of the normally round cornea causing it to bulge forward forming a conical shape. This irregularity in the cornea results in the formation of a distorted image of objects on the retina & gives rise to blurred vision.
Symptoms & signs
- Blur vision even with glasses.
- Frequent change in glasses prescription with fluctuation in the vision.
- Glare & sensitivity to light especially during night.
Keratoconus can be diagnosed at an early stage with detailed eye examination which includes retinoscopy, Slit lamp examination & tests like corneal topography to check the shape & curvature of cornea & Pachymetry to determine the thickness of the cornea.
Exact causes of Keratoconus is not known but it may have some genetic predisposition. It may transmit from parent to children & affect more than one family member. It is also associated with excessive rubbing as it is more common in allergic conjunctivitis patients who have itching & tend to rub their eyes more frequently.
Other risk factors are overexposure to ultra violet rays, chronic eye irritation & improperly fitting contact lenses.
1) Glasses/ Contact lens In early stages, when the cornea is still regular, corrective prescription glasses or soft contact lenses can help the patient. As keratoconus advances, the corneal surface becomes increasingly irregular & these options do not help adequately. In intermediate & advanced stage, various other treatment options & different types of contact lenses are available. Rigid Gas permeable contact lenses provides a smooth refractive surface replacing the irregular cone like surface of the cornea, thus enabling the patient to see clearly. Apart from RGP there are other lenses especially for keratoconus patients like Piggy bag lenses, Scleral lens, Minisclerals, Hybrid lenses for restoring the vision.
2) Surgical C3R (CORNEAL COLLAGEN CROSSLINKING) with riboflavin is the latest addition to treatment options for early progressive keratoconus. This is minimally invasive day care procedure that stabilizes the keratoconus and prevents further deterioration of vision. With newer corneal topography equipments it is easy to pick up early keratoconus and C3R in such cases further progression of keratoconus and thus reduces visual morbidity. C3R is a safe procedure for early progressive keratoconus.
3) Keratoplasty – This involves corneal transplantation either full thickness cornea (PK- Penetrating Keratoplasty) or only the anterior layers of the cornea (DALK- Deep Anterior Lamellar Keratoplasty)
In penetrating keratoplasty the entire recipient cornea is replaced with full thickness donor cornea. This type of penetrating surgery is usually indicated for full thickness corneal opacity, failed grafts and macular corneal dystrophy.
DALK (Deep anterior lamellar Keratoplasty)
This is one of the recent modifications of keratoplasty where full thickness transplantation is not done. This type of transplantation involves replacing only the superior diseased layers of cornea with healthy donor tissue .This procedure has faster recovery period and minimal risk of rejection. Also visual outcome is better. This surgery is indicated in cases with advanced Keratoconus, superficial scar.
- If there is a genetic predisposition or a family history then all family members should be screened timely.
- Regular eye checkup starting at an early age is a must.
- Close watch on glasses power fluctuation can help detect keratoconus at an early stage.
- Avoid excessive eye rubbing and treat eye allergies early.
Keratoconus if diagnosed at an early stage can help us preserve vision and improve the quality of life.
3) Corneal dystrophies
Corneal dystrophies are a group of rare, genetic diseases that affect the cornea. There are more than 20 types of dystrophies. All cause a buildup of foreign material in one or more layers of the cornea. Over time vision may become cloudy or blurry. Corneal dystrophies get worse slowly. It often takes years, even decades, before one may notice problems. Some people with corneal dystrophies have no symptoms.
Corneal dystrophies are grouped by which layers of the cornea they affect. There are three major categories.
- 1. Anterior or Superficial Corneal Dystrophies affecting the anterior part of the cornea.
- 2. Stromal Corneal Dystrophies affecting the stroma, or center layer of your cornea.
- 3. Posterior Corneal Dystrophies affecting the inner part of the cornea.
- • Watery eyes
- • Blur vision
- • Dry eyes
- • Glare
- • Sensitivity to light
- • Pain in the eye
- • The feel of something in your eye
- • Corneal erosion
Treatment depends on the symptoms and type of dystrophy. If there are no symptoms, just regular checkups to keep track of the disease. As the symptoms get worse, other treatment options include medications. If vision is bad enough corneal transplant may be needed. There are 4 types of corneal transplant
- 1) Penetrating keratoplasty
- 2) DALK
- 3) DSEK
- 4) DMEK
DSEK (Descemets stripping endothelial keratoplasty)
DSEK is the most recent addition to the armamentarium to treat endothelial disease of cornea. This modification in keratoplasty replaces the diseased descemets and endothelium with healthy donor endothelium, descemets’ membrane and posterior stroma and requires no sutures. As this procedure is sutureless it has several advantages like faster recovery, better visual outcome and less risk of suture infection.
4) Corneal Edema
- • Cause
- • Symptoms
- • Treatment
- • Recovery
Corneal edema is swelling of the cornea — the clear, dome-shaped outer surface of the eye that helps you see clearly. It’s caused by fluid buildup in the cornea. When untreated, corneal edema can lead to cloudy vision.
The cornea is made up of layers of tissue that help focus light on the back of the eye to produce clear images. Along the inner surface of the cornea is a layer of cells called the endothelium. Its job is to pump out any fluid that collects inside the eye.
When endothelial cells are damaged, fluid can build up and cause the cornea to swell, clouding vision. Endothelial cells can never regenerate. Once they’re damaged, they’re gone for good.
Diseases that damage endothelial cells and can cause corneal edema include:
- Fuchs’ endothelial dystrophy (or Fuchs’ dystrophy) is an inherited disease that gradually destroys endothelial cells.
- Endotheliitis is an immune response that leads to inflammation of the endothelium. It’s caused by the herpes virus.
- Glaucoma is a disease in which pressure builds up inside the eye. The pressure can build to the point where it damages the optic nerve and, in some cases, lead to corneal edema. This is uncommon, however.
- Posterior polymorphous corneal dystrophy is a rare, inherited condition of the cornea.
- Chandler’s syndrome is a rare disorder in which cells of the epithelium multiply too quickly.
Cataract surgery can also damage endothelial cells. Usually the damage isn’t extensive enough to cause problems, but sometimes it can cause corneal edema.
Corneal edema that occurs after cataract surgery is called pseudophakic corneal edema or pseudophakic bullous keratopathy.
As the cornea swells and fluid builds up, vision gets blur or cloudy. One may notice that the sight is especially hazy when waking up in the morning, but it gets better throughout the day.
Other symptoms of corneal edema include:
- haloes around lights
- eye pain
- the feeling that a foreign object is in your eye
If corneal edema is mild, no treatment is needed. To temporarily relieve the swelling in the eye, topical medications may be given.
If the swelling gets severe enough to damage the vision, one may need to have a surgery to replace either the whole cornea or just the endothelial layer with healthy corneal tissue from a donor. Procedures used to treat corneal edema include:
- 1) DSEK
- 2) DMEK
Descemet’s Membrane Endothelial Keratoplasty (DMEK)
Descemet membrane endothelial keratoplasty (DMEK) is the most recent solution to treat the decreased vision due to corneal oedema seen in Fuchs dystrophy, bullous keratopathy, and other causes of poor corneal endothelial function. There are three generations in the evolution of corneal transplantation and DMEK is the third and latest. In DMEK the diseased innermost layer of the cornea is removed surgically and the corresponding thin layer from a healthy donor cornea is put in its place. The thin delicate transplant is secured with only an air bubble. DMEK provides quick improvement in vision with reduced risk of rejection making it keratoplasty of choice in patients with corneal oedema.
Benefits of DMEK
- • 2.8 mm or smaller corneal incision
- • No increase in corneal thickness
- • Quick visual recovery so patients can resume daily activities early
- • Better visual outcomes compared to other keratoplasty methods
- • Reduced risk of vision threatening graft rejection episodes
Healing time and recovery
Recovery time depends on the severity of your corneal edema, and how it’s treated. Mild corneal edema might not cause any symptoms or require treatment. If surgery is done to replace the entire cornea, it could take weeks or longer to get the vision back fully.
5) Corneal tear
The cornea is the clear front window of the eye. A corneal laceration or tear is a cut on the cornea. It is usually caused by something sharp flying into the eye. It can also be caused by something striking the eye with significant force, like a metallic hand tool. A corneal laceration is deeper than a corneal abrasion, cutting partially or fully through the cornea. If the corneal laceration is deep enough it can cause a full thickness laceration. This is when the laceration cuts completely through the cornea and causes a ruptured globe, a tear into the eyeball itself. A corneal laceration is a very serious injury and requires immediate medical attention to avoid severe vision loss.
If your eye has been injured, you should do the following:
- gently place a shield over the eye to protect it. Wear this to protect your eye until you get medical help.
- do not rinse with water
- do not remove the object stuck in eye
- do not rub or apply pressure to eye
- after you have finished protecting the eye, see a physician immediately
- If timely treatment is taken for a corneal abarasions, laceration or full thickness corneal tear then chances of loss of vision becomes lesser and chances of visual recovery are better.
6) Corneal Ulcer/ Keratitis.
A corneal ulcer is an open sore that forms on the cornea. It’s usually caused by an infection. Even small injuries to the eye or erosion caused by wearing contact lenses too long can lead to infections.
The main cause of corneal ulcers is infection.
1) Acanthamoeba keratitis
This infection most often occurs in contact lens wearers. It is an amoebic infection and, though rare, can lead to blindness.
2) Herpes simplex keratitis
Herpes simplex keratitis is a viral infection that causes repeated flare-ups of lesions or sores in the eye. A number of things can trigger flare-ups, including stress, prolonged exposure to sunlight, or anything that weakens the immune system.
3) Fungal keratitis
This fungal infection develops after an injury to the cornea involving a plant or plant material. Fungal keratitis can also develop in people with weakened immune systems.
4) Other causes
- • dry eye
- • eye injury
- • inflammatory disorders
- • wearing unsterilized contact lenses
- • vitamin A deficiency
People who wear expired soft contact lenses or wear disposable contact lenses for an extended period (including overnight) are at an increased risk for developing corneal ulcers.
One may notice signs of an infection before being aware of the corneal ulcer. Symptoms of an infection include:
- • itchy eye
- • watery eye
- • pus-like discharge from the eye
- • burning or stinging sensation in the eye
- • red or pink eye
- • sensitivity to light
Symptoms and signs of the corneal ulcer itself include:
- • eye inflammation
- • sore eye
- • excessive tearing
- • blurred vision
- • white spot on your cornea
- • swollen eyelids
- • pus or eye discharge
- • sensitivity to light
- • feeling like something is in your eye (foreign body sensation)
All symptoms of corneal ulcers are severe and should be treated immediately to prevent blindness. A corneal ulcer itself looks like a gray or white area or spot on the usually transparent cornea. Some corneal ulcers are too small to see without magnification, but you’ll feel the symptoms.
Once the eye doctor discovers the cause of the corneal ulcer, they can prescribe an antibacterial, antifungal, or antiviral eye medication to treat the underlying problem. In severe cases, the corneal ulcer may warrant a corneal transplant. A corneal transplant involves the surgical removal of the corneal tissue and its replacement with donor tissue.
The best way to prevent corneal ulcers is to seek treatment as soon as you develop any symptom of an eye infection or as soon as your eye is injured.
Other helpful preventive measures include:
- avoiding sleeping while wearing your contact lenses
- cleaning and sterilizing your contacts before and after wearing them
- rinsing your eyes to remove any foreign objects
- washing your hands before touching your eyes
Some people may also develop a severe loss of vision along with visual obstruction due to scarring over the cornea. Corneal ulcers can also cause permanent scarring on the eye. In rare cases, the entire eye may suffer damage. Although corneal ulcers are treatable, and most people recover quite well after treatment, a reduction in eyesight may occur.
Why choose us?
At AGRAWAL EYE HOSPITAL we have an expert team of talented and skilled doctors who have an access to the latest diagnostic and surgical modalities. These doctors have been trained from the top notch institutes of India namely LVPEI and Narayana Nethralaya give deliver the best for you. Please feel free to contact us for any further querries or doubts. We are always glad to help you.