Glaucoma / Corneal Diseases
Glaucoma
Glaucoma is actually a class of disorders that develop in a similar way. The amount of aqueous (pronounced a-kwee-us) humor, a watery fluid that fills the inside of the eyeball, begins to build up. As more of this fluid collects, it places greater pressure on all parts of the eye, including the optic nerve. Eventually the excess pressure destroys the nerve. It is the leading cause of preventable blindness in the US.
More than two million people in this country have glaucoma, and about 80,000 are legally blind because of it. The condition is about three times as common among African Americans as among whites. The risk for glaucoma increases rapidly with age, but the condition can affect any age group, including newborn infants and fetuses.
What Are Common Types of Glaucoma?
There are four major types of glaucoma: open angle (chronic), angle closure (acute), congenital, and secondary. All four types are characterized by increased pressure within the eyeball, causing progressive damage to the optic nerve.
Often, there are no symptoms. Vision stays normal, and there is no pain. However, as the disease progresses, a person with glaucoma may notice his or her side vision gradually failing. Objects in the front may still be seen clearly, but objects to the side may be missed. As glaucoma worsens, the field of vision narrows and blindness results. Optic nerve damage reduces side vision first, and then central vision is affected. The result without proper treatment could be blindness.
Risk factors for glaucoma include ethnicity, increasing age, diabetes, and the presence of glaucoma in another family member.
Your eye doctor will take a detailed medical history followed by a comprehensive eye examination. The pressure inside the eye is called intraocular pressure (IOP), and if it is high, that is often a sign of glaucoma. To measure IOP, the doctor uses a tonometer, which may blow a puff of air onto your eye, or it may be placed directly on your eye after it has been numbed with eye drops.
Glaucoma may be treated with either medication or surgery. Medication is usually tried first. The drugs used are substances that reduce intraocular pressure. In general, they either decrease the rate at which aqueous humor is produced in the eye, or they increase the rate at which it is drained off. Various individual drugs and combinations of drugs may have to be tried to see which works best for any one patient.
Some patients do not respond well to medication. In such cases, special shunts may be inserted to open up the canals through which aqueous humor drains out of the eye. This surgical procedure provides a filtering channel, relieving the pressure within the eye.
Dr. Panzo was the first physician in Lake County to use the leading-edge SLT Laser technology, which sends out tiny bursts of low-energy laser light to treat patients with open angle glaucoma, the most common form. The SLT reduces intraocular pressure, creates no scarring of the inner eye meshwork, and may reduce the need for lifelong use of eye drops or medications and the resulting side effects those medications may cause.
Corneal Diseases
The cornea is the transparent tissue that covers the front of the eye. It helps provide a physical barrier that shields the inside of the eye from germs, dust, and other harmful matter, and acts as the eye’s outermost lens.
When light strikes the cornea, it bends – or refracts – the incoming light onto the crystalline lens, which then focuses the light onto the retina, the paper-thin tissue at the back of the eye that starts the translation of light into vision.
Although much thinner than the lens, the cornea provides about 65 percent of the eye's power to bend light. Most of this power resides in the center of the cornea, which is rounder and thinner than the outer part of the tissue and is thus better suited to bend lightwaves.
The cornea is essential to good vision.
The cornea copes very well with minor injuries or abrasions. If dirt scratches the highly sensitive cornea, epithelial cells slide over quickly and patch the injury before infection occurs and vision is affected.
But if the scratch penetrates the cornea more deeply, the healing process will take longer, resulting in greater pain, blurred vision, tearing, redness, and extreme sensitivity to light. These symptoms require professional treatment. Some of the more serious problems that affect the cornea are:
Microbial Infections (keratitis)
When the cornea is damaged, such as after a foreign object has penetrated the tissue, bacteria or fungi can pass into the cornea, causing a deep infection and inflammation. This condition may cause severe pain, reduce visual clarity, produce a corneal discharge, and perhaps erode the cornea.
As a general rule, the deeper the corneal infection, the more severe the symptoms and complications.
Conjunctivitis ("pink eye")
This term describes a group of inflammatory and often contagious diseases of the conjunctiva (the protective membrane that lines the eyelids and covers exposed areas of the sclera, or white of the eye). These diseases can be caused by a bacterial or viral infection, drug allergy, environmental irritants, or a contact lens product.
At its onset, pink eye is usually painless and does not adversely affect vision. The infection will come and go in most cases without requiring medical care. But for some forms of pink eye, such as epidemic keratoconjunctivitis, treatment will be needed. If treatment is delayed, the infection may worsen and cause corneal inflammation and a loss of vision.
Ocular Herpes
Although ocular herpes can result from the sexually transmitted herpes simplex II virus, it is usually caused by herpes simplex virus I (HSV I), the virus responsible for cold sores. In about 12 percent of those with ocular herpes, both eyes are involved.
Ocular herpes produces a relatively painful sore on the surface of the cornea. Prompt treatment with a anti-viral drug will help to stop the herpes virus from multiplying and destroying epithelial cells.
Like other herpetic infections, herpes of the eye remains a controllable, but incurable, problem.
Herpes Zoster (shingles)
This infection is produced by the varicella-zoster virus, the same virus that causes chicken pox. After an initial outbreak of chicken pox (often during childhood), the virus remains dormant within the nerve cells of the central nervous system. But in some people, the varicella-zoster virus will reactivate at some time during their lives. When this occurs, the virus travels down long nerve fibers and infects some part of the body, producing a blistering rash (shingles), fever, painful inflammations of the affected nerve fibers, and a general feeling of malaise.
Varicella-zoster virus may travel to the head and neck, perhaps involving an eye, part of the nose, mouth, cheek, and forehead. In about 40 percent of those with shingles in this area, the virus infects the cornea. These zoster-related corneal lesions will usually clear up on their own. But without early anti-viral treatment, a person runs the risk of the virus infecting cells deep within the tissue, causing inflammation and scarring of the cornea. The disease may also cause decreased corneal sensitivity. For many, this decreased sensitivity will be permanent.
Be aware that corneal complications may arise months after the shingles are gone. For this reason, it is important that patients schedule follow-up eye examinations.
Corneal Dystrophies
There are over 20 corneal dystrophies that affect all parts of the cornea.
Corneal transplant surgery is performed to replace the clear surface on the front of the eye (the cornea).
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Corneal transplantation is recommended for persons who have:
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Thinning of the cornea that causes vision problems (keratoconus)
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Scarring of the cornea from severe infections or injuries
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Cloudiness of the cornea that causes vision loss (Fuchs dystrophy)
Gregory Panzo, M.D.
Jeffrey Baumann, M.D.
Keith Charles, M.D.