The vitreous gel does not grow back once it has been surgically removed. After a vitrectomy, the eye’s cavity fills with aqueous humor, the watery fluid the eye already produces continuously, and this liquid replacement becomes permanent. The original gel was a one-time biological product laid down mostly before birth, and adult eyes lack the cellular machinery to rebuild it. That might sound alarming, but millions of people live with fluid-filled eyes after vitrectomy and see well. The story of what happens inside the eye after vitreous removal, and why it matters, is more nuanced than a simple yes or no.
What the Vitreous Actually Is
The vitreous body is a transparent, jelly-like substance that fills roughly 80 percent of the eye’s interior volume. Its structure depends on a scaffold of collagen fibers with hyaluronic acid filling the spaces between them. Hyaluronic acid is the main sugar-based molecule in the vitreous, and its interaction with collagen helps maintain the gel’s form.1PubMed. Human vitreous hyaluronidase: isolation and characterization Interestingly, though, experiments have shown that you can strip away the hyaluronic acid without completely collapsing the collagen network. The hyaluronic acid is not strictly necessary for holding the collagen fibers apart, though it does boost the gel’s mechanical resilience.2PubMed. Structural macromolecules and supramolecular organisation of the vitreous gel
The cells responsible for producing vitreous components are called hyalocytes, and they play a role in synthesizing and breaking down vitreous material, maintaining transparency, and monitoring the boundary between the vitreous and the retina.3PubMed Central. Hyalocytes-guardians of the vitreoretinal interface During embryonic development, both the neural retina and cells within the vitreous itself contribute collagen at different stages.4PubMed Central. Vitreous body collagen. Evidence for a dual origin from the neural retina and hyalocytes By the time you are born, however, the bulk of this construction work is finished. Adult hyalocytes maintain and repair existing vitreous to a degree, but they cannot reconstruct the entire gel from scratch after it has been removed wholesale.
Why the Gel Cannot Rebuild Itself
Researchers recognized this limitation decades ago. Early vitreous surgeons noted that “the fibrillar structure of the vitreous once destroyed could not be regenerated,” which led them to experiment with vitreous transplantation from donor eyes instead.5PubMed. Early descriptions of vitreous surgery The reason comes down to developmental biology. The vitreous is assembled through a tightly choreographed process in which retinal cells and hyalocytes lay down collagen in a precise three-dimensional network during fetal life. Adult cells simply do not re-enter that developmental program. It is somewhat analogous to how your ear cartilage does not regrow if surgically removed; the tissue was sculpted during development in a way that adult repair processes cannot replicate.
After vitrectomy, aqueous humor seeps in from the front of the eye and gradually fills the vitreous cavity. Aqueous humor is produced continuously by a structure called the ciliary body, and the eye has a constant inflow-outflow cycle that keeps its internal pressure stable. This liquid is far less viscous than the original gel, and that difference has real consequences for how the eye functions afterward.
What Fills the Eye During and After Surgery
During vitrectomy, surgeons do not simply leave the cavity empty. The immediate fill depends on why the surgery was performed. For straightforward procedures like floater removal, the cavity is usually filled with a balanced salt solution that the body’s own aqueous humor gradually replaces. For more complex repairs, especially retinal detachment, surgeons use temporary tamponades to hold the retina in place while it heals.
Gas Tamponades
The most common tamponades are intraocular gases, particularly sulfur hexafluoride (SF₆) and perfluoropropane (C₃F₈). When injected, these gases go through three phases: first they expand as nitrogen from the bloodstream diffuses into the bubble faster than the gas itself diffuses out; then they reach an equilibrium; and finally they slowly dissolve and are absorbed by the blood.6PubMed Central. Complications Associated with the Use of Expandable Gases in Vitrectomy As the gas shrinks and disappears over days to weeks, aqueous humor fills the remaining space.7AIChE Journal. Modeling the dynamics of tamponade multicomponent gases during retina reattachment surgery Patients with a gas bubble must often maintain specific head positions so the bubble presses against the right area of the retina, and they cannot fly in an airplane until the gas has fully absorbed, because altitude changes can cause dangerous pressure spikes.
Silicone Oil
For more severe retinal conditions, surgeons may choose silicone oil instead. Unlike gas, silicone oil does not absorb on its own and can remain in the eye for months or even years. The decision to use it depends on how severe the retinal disease is and the surgeon’s experience with the case.8PubMed. Complications of Silicone Oil as Vitreous Tamponade in Pars Plana Vitrectomy: A Mini Review Silicone oil typically requires a second surgery for removal once the retina has stabilized. After the oil comes out, aqueous humor once again becomes the permanent replacement fluid.
Neither gas nor silicone oil is a true vitreous substitute. They serve a mechanical purpose, pressing the retina flat, but they do not replicate the gel’s biological properties. Once they are gone, you are left with the same aqueous-filled cavity as anyone else who has had a vitrectomy.
How an Aqueous-Filled Eye Differs From a Gel-Filled One
The shift from a viscous gel to a watery fluid changes the internal physics of the eye in ways that matter clinically. Molecular transport speeds up when the vitreous is replaced with less viscous saline or aqueous, because diffusion and convection move faster through thinner fluids.9PubMed. Physiology of vitreous surgery That means oxygen, growth factors, and other signaling molecules can travel more freely across the eye’s interior.
One of the most studied consequences is a rise in oxygen levels near the lens. In eyes with an intact vitreous, oxygen tension near the lens is relatively low. After vitrectomy, oxygen tension measured adjacent to the lens jumped substantially, and in the mid-vitreous it rose even higher. The difference was highly significant. Eyes that had previously undergone vitrectomy and had the gel removed showed even higher oxygen levels than eyes undergoing their first vitrectomy.10American Journal of Ophthalmology. Vitrectomy surgery increases oxygen exposure to the lens: A possible mechanism for nuclear cataract formation This elevated oxygen exposure is thought to be a key driver of the most common long-term side effect of vitrectomy: cataract formation.
Cataracts After Vitrectomy
If you still have your natural lens at the time of vitrectomy, the odds of developing a cataract afterward are high. Most studies put the rate well above 50 percent within a few years, and for many patients it approaches near-certainty over a long enough timeline. The causes are multifactorial. Advanced age, pre-existing lens changes, exposure to the surgical light, oxidation of lens proteins by the newly elevated oxygen, contact with gas or silicone oil tamponades, incidental mechanical contact during surgery, and even prolonged exposure to the irrigating fluid used during the operation all contribute.11PubMed. Cataract Following Pars Plana Vitrectomy: A Review
For this reason, some surgeons recommend combining vitrectomy with cataract surgery in older patients, removing the natural lens and implanting an artificial one at the same time. This avoids a second operation later and sidesteps the cataract problem entirely, though it only makes sense in patients whose lenses are already showing some age-related change.
Pressure Changes and Glaucoma Risk
Vitrectomy can affect intraocular pressure both in the short and long term. Gas and silicone oil tamponades can cause spikes in eye pressure right after surgery if the fill volume is not carefully calibrated. Over the longer term, retinal surgery in general, including vitrectomy, can lead to sustained pressure elevation and, if untreated, glaucomatous damage to the optic nerve.12PubMed Central. Glaucoma management after vitreoretinal surgeries
Several mechanisms have been proposed for this late-onset pressure rise. Postoperative inflammation and microscopic debris can clog the drainage pathways that normally keep eye pressure in balance. The optic nerve may also become more susceptible to damage after vitrectomy. And there is a hypothesis that chronic oxidative stress, a consequence of the higher oxygen levels in a vitrectomized eye, can gradually alter the drainage tissue itself over time, impairing its ability to regulate pressure.13Scientific Reports. Effect of pars plana vitrectomy on early and long-term intraocular pressure and its determinants Routine eye pressure monitoring after vitrectomy is standard practice for this reason.
Visual Outcomes and Quality of Life
Despite the fact that the vitreous is permanently gone, most people see well after vitrectomy. Studies across a range of retinal conditions have found that vitrectomy significantly improves best-corrected visual acuity and contrast sensitivity for most disease groups.14Investigative Ophthalmology & Visual Science. Vision-Related Quality of Life and Visual Function after Vitrectomy for Various Vitreoretinal Disorders The improvement is driven by correcting the underlying retinal problem, not by anything the replacement fluid does.
For people who undergo vitrectomy specifically to treat bothersome floaters, the functional gains can be dramatic. One study found that about 84 percent of patients were completely cured of their troublesome floaters, with an additional 9 percent reporting significant improvement.15PubMed. Pars plana vitrectomy for disturbing primary vitreous floaters: clinical outcome and patient satisfaction Long-term follow-up shows satisfaction rates around 88 percent.16PubMed. Longterm follow-up of pars plana vitrectomy for vitreous floaters: complications, outcomes and patient satisfaction Objective measurements back this up: one study found a roughly 60 percent reduction in vitreous opacity density after vitrectomy for floaters, along with meaningful improvements in contrast sensitivity and quality-of-life scores.17PubMed Central. Clinical Management of Vision Degrading Myodesopsia from Vitreous Floaters: Observation vs. Limited Refractive Vitrectomy Self-reported measures of glare, near-sight difficulty, and the annoyance of floater movement all improved substantially as well, with a median reduction of about 69 percent on a composite impairment index three months after surgery.18PubMed. 23G pars plana vitrectomy for vitreal floaters: prospective assessment of subjective self-reported visual impairment and surgery-related risks during the course of treatment
For retinal detachment repair, the primary success rate of vitrectomy is around 85 percent, meaning the retina stays attached after a single procedure. Among cases that do redetach, the vast majority occur within the first few months.19PubMed Central. Long-term Clinical Results of Vitrectomy and Scleral Buckling in Treatment of Rhegmatogenous Retinal Detachment
Can You Skip Surgery Entirely With Enzymes?
One question that naturally arises is whether the vitreous can be dissolved pharmacologically rather than surgically removed. An injectable enzyme called ocriplasmin was developed to do exactly that. It breaks the protein bonds that anchor the vitreous to the retina, and it is approved for treating conditions where the vitreous pulls on the macula. In cases of vitreomacular traction, ocriplasmin resolved the traction in about 71 percent of treated eyes after six months, compared to 100 percent for vitrectomy.20PubMed. Pharmaological vitreolysis with ocriplasmin as a treatment option for symptomatic focal vitreomacular traction with or without macular holes compared to tranconjunctival vitrectomy
A meta-analysis comparing the approaches found that vitrectomy was significantly more effective for releasing traction and closing macular holes than ocriplasmin, achieving traction release in essentially all cases versus roughly 46 percent for the enzyme, and macular hole closure rates of 95 percent versus 46 percent.21PubMed Central. Pneumatic vitreolysis versus vitrectomy for the treatment of vitreomacular traction syndrome and macular holes: complication analysis and systematic review with meta-analysis of functional outcomes The enzyme is less invasive, avoids the operating room, and carries a lower risk profile, so it remains useful for milder cases. But it does not replace the vitreous with anything either. When ocriplasmin works, it liquefies the vitreous in place. The gel structure is destroyed rather than rebuilt.
The Search for a True Vitreous Replacement
If the body cannot regenerate the vitreous, could we engineer a substitute? This is an active area of research, and the honest answer is that nothing clinically available yet replicates what the natural vitreous does. Current tamponades like gas and silicone oil are functional stopgaps, not true substitutes. They lack the structure and biological functions of the real thing.
The most promising experimental approach involves hydrogels, engineered materials designed to mimic the transparency and flexibility of the native vitreous. Researchers are working with natural polymers like hyaluronic acid and collagen, as well as synthetic ones like polyethylene glycol and polyvinyl alcohol, trying to find the right combination that stays clear, has appropriate stiffness, and does not provoke an immune response.22PubMed Central. Hydrogel-Based Vitreous Substitutes One particularly creative approach used a DNA-based supramolecular hydrogel that showed mechanical properties similar to human vitreous, could be injected through a needle, and maintained eye structure and function in animal experiments without obvious inflammation.23Advanced Materials Interfaces. DNA Supramolecular Hydrogel as a Biocompatible Artificial Vitreous Substitute
These experimental substitutes are still far from routine clinical use. The challenge is not just finding a material that is clear and non-toxic. A true vitreous replacement would ideally regulate oxygen transport the way the native gel does, support the retina mechanically, and remain stable for decades without degrading or migrating. That is a tall order, and most materials tested so far fall short on at least one of those criteria.
Living Without a Vitreous
For most people facing vitrectomy, the practical reality is reassuring. The eye adapts surprisingly well to aqueous humor as a permanent fill. You will not feel the difference. The fluid is produced and drained continuously, so the eye maintains its shape and pressure through the same mechanisms it always used. Vision often improves after surgery because the underlying retinal problem that prompted the procedure has been addressed.
The tradeoffs are real but manageable. If you still have a natural lens, expect cataracts eventually, and plan accordingly. Have your eye pressure checked regularly. Understand that the gas or oil bubble phase after surgery is temporary and requires patience, whether that means lying face-down for days or avoiding air travel for weeks. And know that while your eye will never rebuild its original gel, the absence of that gel is not what threatens your vision. It is the retinal condition the surgery was designed to fix, and on that front, vitrectomy remains one of the more successful interventions in modern ophthalmology.
What Elevated Oxygen Does Beyond Cataracts
The oxygen story inside a vitrectomized eye extends beyond the lens. Measurements have shown that previous vitrectomy is associated with significantly increased oxygen tension in the posterior chamber of the eye.24PubMed Central. Oxygen distribution in the human eye: relevance to the etiology of open-angle glaucoma after vitrectomy The intact vitreous gel acts as a kind of oxygen buffer, consuming some oxygen through its own metabolic activity and slowing diffusion through its thick, viscous matrix. Once the gel is gone and replaced by watery fluid, oxygen from the well-vascularized retina can diffuse freely throughout the eye. This is not inherently dangerous in every case, but it shifts the biochemical environment.
Researchers have linked this chronic oxygen elevation to more than just cataract formation. The trabecular meshwork, the tissue responsible for draining fluid from the eye and regulating pressure, may sustain oxidative damage over years, potentially contributing to the late-onset glaucoma that some vitrectomy patients develop. The lens, the drainage tissue, and possibly other structures in the anterior eye are all exposed to an oxidative load they were never designed to handle. How much this matters likely depends on individual factors like the health of a person’s antioxidant defenses, their age, and whether they have other risk factors for glaucoma or cataract. For younger patients who may live with a vitrectomized eye for decades, these cumulative effects deserve more long-term study than the field has so far provided.