Provider’s New Doctors Add Eye Expertise

Cornea and glaucoma specialists join the institute’s team

Chris Donovan, MD

Chris Donovan, MD

The eyes are two of the body’s most complex organs. Unfortunately, their complexity exposes them to a multitude of ailments.

The staff at Florida Eye Specialists & Cataract Institute addresses those problems, and to do so, the practice recently added two physicians to its expanding team.

Chris Donovan, MD, is fellowship-trained in cornea and external disease. His areas of focus are cornea, cataract and refractive surgery. During his fellowship, Dr. Donovan became skilled at performing the most advanced forms of cornea transplant surgery.

“The cornea consists of five layers,” he educates. “There’s an outer cellular layer and three different internal layers that are predominantly extracellular matrix and collagen. The fifth layer, the endothelium, lies on the posterior side of the cornea and performs a pumping function to keep the cornea dehydrated.

“There are many conditions that can affect the layers, from corneal infections to ectasia, where the cornea becomes thin and weak. Keratoconus, in which the cornea is cone-shaped instead of round, is a type of ectasia. There are certain dystrophies as well, including Fuchs’ dystrophy, where the endothelium fails to perform its pumping function and the cornea swells, distorting vision.”

In the past, these conditions were often treated using a full-thickness cornea transplant. Today, there are several less invasive variations of that procedure that allow physicians to transplant only the diseased layers of the cornea, Dr. Donovan reveals.

“There are lamellar transplants, which involve only the anterior layer of the cornea, and posterior transplants, in which we transplant just the rear cellular layer,” he elaborates. “Diseases of the deep internal layer of the cornea require a very refined surgical technique called DMEK.

“There have been significant advancements in cataract surgery over the past few years.” – Dr. Donovan

“DMEK stands for Descemet membrane endothelial keratoplasty. It’s one of the two surgeries that are typically performed to treat Fuchs’ dystrophy. The other is DSAEK, Descemet-stripping automated endothelial keratoplasty.”

The Descemet membrane is the basement membrane for the corneal endothelium. Lying deep in the cornea, the Descemet membrane anchors the endothelium to the cornea. During DMEK and DSAEK, this membrane is removed and replaced with healthy donor tissue.

“DMEK involves transplanting a very thin layer of tissue. DMEK is considered the most advanced evolution of the surgical techniques for Fuchs’ dystrophy,” Dr. Donovan asserts. “Where DSAEK typically involves transplanting a graft that’s anywhere from 65 to 100 microns, the DMEK graft is as thin as 15 microns.

“Because it’s so small, the DMEK graft generally arrives in a scroll. Through a very small wound in the cornea, we inject the scroll into the cornea’s anterior chamber, where we unfold it using a variety of techniques. DSAEK is a great surgery, but DMEK is a newer technique that can offer patients even better vision.”

Premium Options

Dr. Donovan also performs cataract surgery. Cataracts are a clouding of the natural lens. The only treatment is surgery in which the lens is removed and replaced with a synthetic intraocular lens, or IOL.

“There have been significant advancements in cataract surgery over the past few years,” Dr. Donovan maintains. “By decreasing the size of the corneal wound and the amount of energy placed inside the eye, the procedure has become much safer. We also have many new IOL options we can offer to patients.”

IOLs are made of acrylic or silicone and are coated with a material to protect the eyes from the sun’s ultraviolet rays. During surgery, the replacement lens is rolled up, placed in the eye and unfolded, and side structures called haptics hold it in position.

Like contact lenses, IOLs are available in different focusing powers. Standard IOLs correct vision primarily for distance, but patients can have one eye fixed for distance and the other for reading, an option called monovision.

A third option is multifocal IOLs. Most multifocal IOLs are bifocal lenses that correct distance and either reading or intermediate vision. There are now some advanced versions that correct distance, reading and intermediate vision.

Candidacy for premium lenses is determined through a variety of eye measurements as well as the patient’s desire to be glasses-free.

Modern-day ophthalmologists tailor cataract surgery to the patient, Dr. Donovan says.

“The preoperative evaluation is extremely important in determining which lens options we can offer, but the choice of lens ultimately comes down to a personality test,” he explains. “During the preoperative evaluation, we talk about the patients’ vision goals, their hobbies and what they see themselves doing not just now but 10 years from now.”

Damaging Eye Pressure

Elevated ocular hypertension is a common risk factor treated by glaucoma specialist Mohamed Sharaby, MD, who recently joined the staff at Florida Eye Specialists & Cataract Institute.

Dr. Sharaby, who completed residencies and fellowships in neurology and ophthalmology, devotes the bulk of his time to comprehensive glaucoma management and complex cataract surgery. He also offers premium options for cataract surgery and dedicates a small portion of his clinic time to neuro-ophthalmology.

Glaucoma is a progressive eye disorder that damages the optic nerve,” the doctor explains. “It’s associated with increased pressure in the eye due to a buildup of fluid and is the leading cause of irreversible blindness in the world.

“The most common type is open-angle glaucoma. With this type, the drainage angle formed by the cornea and the iris remains open. However, the trabecular meshwork (the spongy tissue that drains the eye) is partially blocked.”

During his fellowship, Dr. Sharaby learned the most advanced procedures for
treating glaucoma.

Minimally invasive glaucoma surgery, or MIGS, is aimed at improving the outward flow of fluid and decreasing eye pressure,” Dr. Sharaby explains. “MIGS is generally performed on patients with mild to moderate open-angle glaucoma and is often done at the end of cataract surgery.”

Canaloplasty is a relatively new MIGS that uses a microcatheter to enlarge the eye’s natural drainage canal and ease the pressure in the eyes. It can be performed alone or with cataract surgery. Pressure can also be eased through a trabeculotomy, in which a piece of tissue is removed to create a pathway for fluid to flow out of the eye.

“In patients with severe glaucoma,” Dr. Sharaby says, “we can do a trabeculotomy using the Omni® Surgical System,” a device that performs implant-free MIGS.

“Minimally invasive glaucoma surgery, or MIGS, is aimed at improving the outward flow of fluid and decreasing eye pressure.” – Dr. Sharaby

“Sometimes, the trabecular meshwork herniates into the drainage canal, causing blockages. Omni trabeculotomy involves using little wires to dilate the passageway in the drainage canal and create a new pathway. It can be performed at the time of
cataract surgery or independently.”

Dr. Sharaby is also skilled in the use of state-of-the-art glaucoma technology, including various stents such as the iStent®, the Hydrus® Microstent and the XEN® stent.

“Stents are tubular devices that are implanted in the eye to create bypasses that help drain the fluid and decrease the pressure in the eyes,” the doctor explains. “They are typically implanted during MIGS.”

Back of the Eye

Mohamed Sharaby, MD

Mohamed Sharaby, MD

“I also treat many neuro-ophthalmic conditions such as idiopathic intracranial hypertension, or IIH, which is high pressure around the brain that causes symptoms such as vision changes and headaches,” Dr. Sharaby notes. “IIH most often affects females and is associated with congestion and inflammation of the optic nerve, causing gradual vision loss.

“The practice of neuro-ophthalmology includes performing BOTOX® injections for headaches and hemifacial spasm, a nervous system disorder in which the muscles on one side of the face twitch involuntarily. I also provide BOTOX injections for cosmetic purposes.”

Other conditions treated by Dr. Sharaby include thyroid eye disease and thyroid orbitopathy, in which people’s eyes bulge secondary to thyroid disease. Another is myasthenia gravis, an autoimmune disorder that destroys neuromuscular connections; sufferers often experience droopy eyelids that obstruct their vision.

“Neuro-ophthalmologists can help make a person’s extraocular muscles, those outside the eye that control its movement, stronger by stimulating their neuromuscular junctions,” Dr. Sharaby describes. “By doing that, the muscles begin to function more normally, which improves the droopiness.”

© FHCN article by Patti DiPanfilo. Photos by Jordan Pysz. mkb
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    • Florida Eye Specialists & Cataract Institute

      The mission of Florida Eye Specialists & Cataract Institute is to deliver the highest quality eye care to ensure superior patient outcomes. They consider their patients an extension of their family, and it shows in their compassion and con... Read More

    • Chris Donovan, MD

      Chris Donovan, MD, earned his Bachelor of Science degree in microbiology and entomology from Cornell University in Ithaca, NY, and his medical degree from Case Western Reserve University Medical School in Cleveland. Dr. Donovan completed a trans... Read More

    • Mohamed Sharaby, MD

      Mohamed Sharaby, MD, earned a bachelor’s and master’s degree in accounting from Florida Atlantic University, then earned his medical degree at St. George’s University Medical School in Grenada. Dr. Sharaby completed a neurology residency at th... Read More