Vitrectomy Surgery With the Constellation System
Understanding Vitrectomy and the Constellation System
A vitrectomy is a surgery to remove the vitreous, the clear gel that fills the inside of the eye. The vitreous can develop problems such as bleeding, scar tissue, or pulling on the retina. Removing it allows a retina specialist to directly treat conditions affecting the retina. The retina is the thin layer of tissue at the back of the eye responsible for vision.
Approximately 225,000 vitrectomy procedures are performed each year in the United States. This represents over 35 percent of the 2.2 million vitrectomies done worldwide (Market Growth Reports, 2024). These numbers reflect how common and well-established this surgery has become.
The Constellation Vision System is a surgical platform that received FDA clearance in 2010 (FDA, K101285). It combines the tools needed for both retina surgery and cataract surgery into one machine. This means a retina specialist can address multiple eye problems during a single procedure when needed.
The system includes a high-speed vitrectomy cutter, a built-in laser, advanced pressure sensors, and a light source. All of these components work together to give the surgeon precise control throughout the operation.
Retina surgery requires extremely delicate movements inside a very small space. The retina is thinner than a sheet of paper. Even slight changes in pressure or imprecise cutting can affect outcomes. The Constellation system was designed to address these challenges through engineering advancements that improve safety and efficiency.
How the Constellation System Works
The Constellation system uses a dual-pneumatic vitrectomy cutter. This means it relies on two separate airflows to open and close the tiny cutting port at the tip of the surgical probe. Older systems used a spring mechanism to return the cutter to its starting position. By removing the spring, the Constellation allows independent control of the opening and closing of the cutter.
The cutting speed can reach up to 10,000 cuts per minute (Alcon Surgical, 2010). Higher cutting speeds allow the vitreous gel to be removed more smoothly. This reduces pulling on the retina during surgery.
Duty cycle refers to how long the cutting port stays open compared to how long it stays closed. The Constellation system offers three modes that give the surgeon flexibility based on the surgical task at hand.
- CORE mode keeps the port open longer than closed. This is used for removing large amounts of vitreous gel efficiently.
- 50/50 mode keeps the port open and closed for equal amounts of time. This provides balanced cutting and suction.
- SHAVE mode keeps the port closed longer than open. This is used for delicate work very close to the retina.
Maintaining stable pressure inside the eye during surgery is critical. If pressure drops too low, the eye can become soft, which increases risk. If pressure is too high, it can damage delicate tissues. The Constellation system uses non-invasive flow sensors that monitor and adjust infusion pressure in real time. This keeps intraocular pressure stable within plus or minus 2 mmHg throughout the procedure.
The Constellation includes a built-in 532nm PurePoint laser. Retina specialists use this laser during surgery to seal retinal tears or treat areas of abnormal blood vessel growth. It can also reinforce weakened areas of the retina. Having the laser integrated into the same platform means the surgeon does not need to switch between separate machines.
The system supports 23-gauge, 25-gauge, and 27-gauge surgical instruments. Gauge refers to the size of the instruments and the incisions needed to insert them. Smaller gauge numbers mean larger instruments. The smallest option, 27-gauge, uses incisions so small they often do not require stitches and may lead to faster healing.
Conditions Treated With This System
A retinal detachment occurs when the retina separates from the tissue underneath it. Without treatment, this can lead to severe and irreversible vision loss. Vitrectomy allows the retina specialist to remove vitreous gel that may be pulling on the retina and flatten it back into place. Laser or freezing treatment is then used to seal the retina. A gas bubble or silicone oil may be placed inside the eye to hold the retina in position while it heals.
Diabetic retinopathy is the most common reason for vitrectomy, accounting for approximately 40 percent of vitrectomy procedures (Market Growth Reports, 2024). Diabetes can cause bleeding inside the eye, called vitreous hemorrhage. It can also cause scar tissue that pulls on the retina, called tractional retinal detachment. The Constellation system helps the surgeon carefully remove blood and scar tissue while minimizing damage to the retina.
Overall vitrectomy rates in the United States increased 31 percent from 2001 to 2012. However, vitrectomy rates among patients with diabetes decreased by 43 percent during that same period. This is likely due to improved medical treatments such as anti-VEGF injections (Ophthalmology, 2016).
A macular hole is a small break in the macula, the central part of the retina responsible for sharp, detailed vision. An epiretinal membrane is a thin sheet of scar tissue that grows on the surface of the macula. It causes distorted or blurry vision. In both cases, vitrectomy allows the retina specialist to peel away the membrane or prepare the macular hole for healing. A gas bubble is often placed in the eye afterward to support the healing process.
When blood leaks into the vitreous gel from damaged blood vessels, it blocks light from reaching the retina. This causes cloudy or dark vision. If the bleeding does not clear on its own, vitrectomy can remove the blood-filled vitreous and restore a clear visual pathway. The underlying cause of the bleeding, such as diabetic retinopathy or a retinal tear, is treated at the same time.
What to Expect Before, During, and After Surgery
Before surgery, a retina specialist will perform a thorough eye exam. Imaging tests such as optical coherence tomography (OCT) or ultrasound may also be ordered. Blood sugar levels should be well-controlled in patients with diabetes, as poor glucose control can increase complications. The specialist will review all current medications, because some blood thinners may need to be adjusted.
Most vitrectomy procedures are performed as outpatient surgery, meaning you go home the same day. You will need someone to drive you home afterward.
Vitrectomy is typically performed under local anesthesia, which numbs the eye and the area around it. You will be awake but should not feel sharp pain. The retina specialist makes tiny incisions in the white part of the eye to insert the surgical instruments. Using the Constellation system, the surgeon removes the vitreous gel and addresses the specific retinal problem.
The procedure usually takes between 30 minutes and two hours, depending on the complexity of the condition. In some cases, a gas bubble or silicone oil is placed inside the eye at the end of surgery to help the retina heal.
If a gas bubble is placed in the eye, you may need to maintain a specific head position for several days or weeks. This is called face-down positioning. It is important because the gas bubble rises and presses against the retina to hold it in place. Your retina specialist will give you specific instructions about how long you need to maintain this position.
You should not fly in an airplane or travel to high altitudes while a gas bubble is in the eye. Changes in air pressure can cause the bubble to expand, raising pressure inside the eye dangerously. The gas bubble dissolves on its own over several weeks.
Vision improvement after vitrectomy is usually gradual. If a gas bubble was used, your vision will be very blurry until the bubble shrinks and is absorbed. This can take two to eight weeks depending on the type of gas used. Final visual results may not be apparent for several months. The amount of vision recovery depends on the underlying condition and how much damage was present before surgery.
Risks and Possible Complications
Some degree of redness, mild discomfort, and blurry vision after surgery is normal. These symptoms usually improve within the first few weeks. Eye drops, including antibiotics and anti-inflammatory medications, are prescribed to prevent infection and reduce swelling. Sensitivity to light is also common during early recovery.
If you have not had cataract surgery, vitrectomy will likely speed up cataract development in the treated eye. Most patients over age 50 who still have their natural lens will develop a visually significant cataract within one to two years after vitrectomy. Cataract surgery can be performed later to address this.
Although serious complications are uncommon, they can include the following.
- Retinal detachment, which may require additional surgery.
- Endophthalmitis, a severe infection inside the eye that requires urgent treatment.
- Increased eye pressure, which can damage the optic nerve if not managed.
- Vitreous hemorrhage, meaning new bleeding inside the eye after surgery.
- Hypotony, or very low eye pressure, which can occur if surgical incisions do not seal properly.
The Next Generation of Vitrectomy Technology
In June 2024, Alcon received FDA clearance for its next-generation Unity VCS. This system is designed to replace the Constellation platform over time (Alcon, 2024). Alcon plans to upgrade existing devices to the Unity platform over the next decade. The new system is intended to improve surgical workflow and introduce new technologies while maintaining compatibility with current techniques.
Recent developments include the Advanced ULTRAVIT Beveled High Speed Probe, which reaches 10,000 cuts per minute (Alcon, 2024). The HYPERVIT Dual Blade probe is capable of 20,000 cuts per minute (Alcon, 2024). Both feature improved bevel tip designs that position the cutting port closer to the end of the probe. This allows retina specialists to work more precisely near the retina surface when removing membranes or scar tissue.
When to See a Retina Specialist
If you have been told you may need a vitrectomy, a retina specialist is the right doctor to evaluate your condition. Retina specialists are ophthalmologists with additional fellowship training in the medical and surgical treatment of retinal diseases. They will determine whether surgery is the best option for your specific situation.
Follow all post-operative instructions carefully, including eye drop schedules and positioning requirements. Attend every follow-up appointment, even if your eye feels fine. Some complications develop without obvious symptoms in the early stages.
Seek immediate care from a retina specialist or go to the emergency room if you experience any of the following after vitrectomy.
- Sudden decrease or loss of vision.
- Severe or worsening eye pain.
- Increasing redness that does not improve.
- New flashes of light or a sudden increase in floaters.
- A shadow, curtain, or dark area in your field of vision.
Questions and Answers
Most vitrectomy procedures take between 30 minutes and two hours. The duration depends on the complexity of the condition being treated. Straightforward cases such as vitreous hemorrhage removal tend to be shorter. Surgeries for complex retinal detachments or advanced diabetic eye disease may take longer. Your retina specialist can give you an estimate based on your specific situation.
Most vitrectomy procedures are performed under local anesthesia, which numbs the eye and surrounding area. You will typically be awake but comfortable. Sedation may also be given to help you relax. General anesthesia, which puts you fully to sleep, is sometimes used depending on the case and patient preference. Your retina specialist and anesthesia team will discuss the best approach before surgery.
Vitrectomy is performed on one eye at a time in nearly all cases. This approach reduces the risk of bilateral complications, particularly infection. If both eyes need surgery, the second eye is typically scheduled after the first eye has healed sufficiently. This is usually several weeks to a few months later.
If a gas bubble or silicone oil tamponade is used, proper positioning is important for the success of the surgery. If you have physical limitations that make face-down positioning difficult, discuss this with your retina specialist before the procedure. Special positioning equipment such as face-down support pillows and rental chairs is available. In some cases, alternative surgical approaches or tamponade agents may be considered.
Recovery timelines vary, but most patients can resume light daily activities within a few days to a week. Strenuous exercise, heavy lifting, and swimming are usually restricted for several weeks. If a gas bubble is in the eye, air travel is not permitted until the bubble has fully dissolved. Your retina specialist will provide a personalized timeline for returning to work, driving, and physical activity.