On this episode of Kentucky Health, host Dr. Wayne Tuckson welcomes ophthalmologist Frank Burns, M.D., to discuss diagnosing and treating two eye diseases that affect many people as they age: glaucoma and cataracts.
Two Ocular Afflictions That Worsen Over Time
While the two leading causes of vision loss in the U.S. are age-related macular degeneration and diabetic retinopathy, the overall leading cause of blindness globally is cataracts – and there are over 20 million Americans who have them in one or both eyes. Glaucoma affects about 3 million people in this country.
“A cataract is basically a cloudy lens in the eye – I used to give the analogy of having a camera with a smudged lens,” Burns says. “Whereas glaucoma is a silent disease, for the most part, until its very advanced. And patients will slowly lose their vision from the outer part, their peripheral vision, and it comes into what we call ‘tunnel vision.’ That’s more of a nerve damage type of disease.”
By age 60, about two-thirds of Americans will have had at least one cataract, Burns says. Risk factors for developing cataracts start with the aging process, kicking in during one’s forties and fifties. Other risk factors include smoking, having a family history, sun exposure, and being nearsighted. “Blocking the rays from sunlight is definitely a way of preventing early cataract formation,” Burns says.
Some people can ward off having cataract surgery if they limit their driving at night and during days with bright sunlight. “Cataracts cause a loss of contrast sensitivity, telling between shades of gray,” Burns says. He adds that they don’t affect a person’s reading vision until they are very advanced, which can also lead patients to hold off on treatment longer than they should. “Some people will come in and they won’t have any complaints and their vision has decreased, and their cataracts are pretty bad, and you have to convince them that they shouldn’t be driving until they get these cataracts removed,” he says.
Burns explains that glaucoma arises when eye pressure burdens the optic nerve over several years, leading to gradual vision loss. This pressure occurs when a meshwork in the eye that drains fluid essential to the eye’s function becomes clogged. The main risk factors for glaucoma are family history and especially being nearsighted. African Americans are also at higher risk for getting glaucoma.
“You can have congenital glaucoma, you can have juvenile glaucoma,” Burns says. “I’ve seen patients in their twenties, thirties, and forties get it, but typically it’s age-related. About 15 percent of patients over 80 have glaucoma and they don’t know it, because there are no symptoms.”
For those with nearsightedness, Burns says that developing it at a young age places one at a higher risk for glaucoma. He notes that in addition to heredity, the habit of spending several hours a day looking at device screens (laptops or smartphones) can increase nearsightedness. “It causes the eye to lengthen,” he explains, “so there is an environmental factor for myopia or nearsightedness that we’re now discovering, and we’re finding treatments for it like using weak dilating drops or atropine that slows down the development of myopia.”
Treatment of Glaucoma and Cataracts: Successful Methods
Macular degeneration – which occurs when part of the eye’s retina deteriorates – and diabetic retinopathy – where blood vessels at the back of the retina become damaged due to diabetes – are mainly irreversible but can be managed. Glaucoma and cataracts, however, can be treated, Burns says.
“For cataracts, there really isn’t any other treatment than surgery,” he says. When meeting with a patient and discussing surgery, Burns will first ask them how they want their vision to function after an artificial lens is put into their eye. In recent years, artificial multifocal lenses have been introduced that correct both distance vision and nearsightedness, and some patients choose that option.
Burns presents a video showing how cataract surgery is performed. After giving the patient – who remains awake – drops to numb the eye, Burns first makes a small incision in the eye and then inserts an ultrasound probe which breaks the cataract into small pieces which are then vacuumed out. Next, he inserts a foldable artificial lens through the incision and places it over the opening, closes the incision, and the procedure is complete in roughly 10-15 minutes. He may perform the surgery using a laser assist to help break up the cataract before the incision; this can help expedite the procedure and speed up recovery time.
“Three and a half million cataract surgeries are performed in the United States per year, and it is one of the most successful procedures, because we have developed techniques that make it a very quick, very painless procedure,” Burns says. “Usually, the patient’s vision responds very quickly – most of them are driving the next day.”
Burns says that a patient will not develop a cataract in their new artificial lens. Around 50 percent of them may have scar tissue form afterward, but it can be removed quickly using a laser.
With glaucoma, Burns says that not every person who develops elevated pressure in the eye will go on to lose vision. “You have to watch these people over many years to see if they have nerve damage,” he explains. “We have testing, we use an optic nerve OCT (optical coherence tomography) and a visual field, which is a peripheral vision test, and follow those patients with elevated pressure to see if they’re getting glaucoma. If they start developing damage, that’s when you treat them. You want to treat them when they have early signs.”
Burns says that some patients will not schedule an appointment with an ophthalmologist until their eye’s optic nerve is already damaged from slowly building pressure. Once damage occurs, it cannot be reversed. Burns prefers using laser treatments to eye drops for glaucoma; both will decrease the amount of pressure in the eye, but he explains that most of the time, lasers are covered by insurance and that eye drops can be very expensive. Plus, the patient has to remember to use the drops every day.
Burns presents a video showing how this laser procedure, called a selective laser trabeculoplasty, works. The patient is given an anesthetic and after that, Burns will use the laser to punch about 100 holes in the meshwork that has become clogged in the eye. He says that the procedure will lower the pressure on the eye’s optic nerve with relief coming around six weeks later.
“About 80 to 95 percent of people get a good response, it will lower the pressure and can last several years and (the patient) doesn’t have to go on drops – and it can be repeated,” he says.
Burns’ main takeaway for viewers is that they should get their eyes checked regularly after age 40. He reiterates that both cataracts and glaucoma occur gradually, often without the patient knowing anything is happening. If a patient notices any sudden changes in vision, such as developing floaters (vision spots), Burns recommends scheduling an appointment as soon as possible.
“If somebody’s very nearsighted and has a higher risk of getting a torn retina, I tell them to come in every year for an eye exam,” he says. “If someone has normal vision but they have to wear glasses and they’re in their forties, they should be checked every three or four years. If you get to 60, even if you don’t have any eye disease, you probably should be checked every couple of years.” But patients with diabetes, Burns adds, should have their eyes checked annually.