A retinal cyst is a fluid-filled pocket that forms within or beneath the layers of the retina, the light-sensitive tissue lining the back of the eye. These cysts arise from a surprisingly wide range of causes, from post-surgical inflammation and vascular disease to inherited genetic conditions and even parasitic infection. Some retinal cysts cause no symptoms at all and are discovered incidentally during a routine eye exam; others blur or distort central vision enough to interfere with reading, driving, and recognizing faces. Treatment depends almost entirely on what caused the cyst in the first place, which makes accurate diagnosis the most consequential step in managing the condition.
How Retinal Cysts Form
The retina is not a single sheet but a stack of specialized cell layers, each with a distinct job in converting light into neural signals. Fluid can accumulate between or within those layers through several distinct mechanisms. The most common is a breakdown of the blood-retinal barrier, the tight junctions that normally keep blood plasma from leaking into retinal tissue. When those junctions fail, fluid seeps into the retina and pools in small pockets, producing what clinicians call cystoid macular edema (CME) when it occurs in the central macula.
But not all retinal cysts involve leaky blood vessels. A separate category of cyst-like spaces forms through degenerative processes that have nothing to do with vascular leakage. In age-related macular degeneration, for instance, cystic cavities can develop over areas of progressive atrophy or chronic scarring, or from mechanical stress caused by underlying deposits pulling on retinal tissue.
1Survey of Ophthalmology. Non-exudative fluid in age-related macular degeneration: Imaging, pathophysiology, and clinical implications These non-vasogenic cysts look similar on some imaging but behave very differently and require different management, a distinction that matters because treating them as ordinary swelling with anti-inflammatory drugs would be futile.
2PubMed. Non-vasogenic cystoid maculopathiesA third mechanism involves physical splitting of the retinal layers themselves, called retinoschisis. In the acquired form, microcystic degeneration causes the neurosensory retina to separate, typically at the outer plexiform layer in the peripheral retina. This affects roughly 2 to 7 percent of people over 40 and is usually bilateral and symptomless.
3Cureus. Acquired Senile Retinoschisis of the Peripheral Retina Imaged by Spectral Domain Optical Coherent TomographyCommon Causes
The list of conditions that can produce retinal cysts is long, but a few account for the vast majority of cases seen in clinical practice.
Post-Surgical Cystoid Macular Edema
One of the most frequent triggers is cataract surgery. Known as Irvine-Gass syndrome, this form of CME develops when surgical inflammation disrupts the blood-retinal barrier weeks to months after the procedure. In a study tracking patients over 12 months, both long-term and short-term personalized treatment approaches produced significant reductions in retinal thickness and meaningful gains in visual acuity, with patients gaining roughly 10 to 13 letters on a standard vision chart from baseline.
4MDPI. Irvine–Gass Syndrome Personalized Treatment Outcomes: A Retrospective Single-Center Cohort Study The reassuring aspect of post-cataract CME is that it usually responds well to treatment, though the timeline varies by patient.
Diabetic Macular Edema
Diabetes damages retinal capillaries over time, and when those vessels begin leaking, fluid accumulates in cystoid spaces in the macula. Diabetic macular edema is one of the leading causes of vision loss in working-age adults worldwide. The cysts that form tend to cluster near the fovea, where even small amounts of fluid can degrade sharp central vision.
5PubMed Central. Cystoid macular edemaRetinal Vein Occlusion
When a vein draining the retina becomes blocked, blood backs up and pressure forces plasma into the surrounding tissue. Central retinal vein occlusion and its branch variants are major causes of macular edema, and the resulting cysts can persist or recur for months if the underlying vascular problem is not managed.
5PubMed Central. Cystoid macular edemaInherited Conditions
X-linked juvenile retinoschisis is a genetic condition affecting males, caused by mutations in the RS1 gene. Unlike acquired retinoschisis, which splits peripheral retinal layers, the congenital form typically produces cyst-like cavities right at the fovea, reducing central vision from childhood. Imaging in affected patients shows characteristic spoke-wheel patterns of cysts, with markedly thickened central retinas averaging around 570 micrometers compared to the normal 250 or so.
6Europe PMC. X-linked juvenile retinoschisis: phenotypic and genetic characterization Retinitis pigmentosa, another inherited retinal disease, can also produce macular cysts, though the underlying mechanism appears to involve chronic low-grade disruption of retinal homeostasis rather than outright vascular leakage.
Less Common and Surprising Causes
Parasitic infection is an underappreciated cause of retinal cysts, particularly in regions where pork tapeworm (Taenia solium) is endemic. The larval form of the parasite can lodge in the eye and form a cystic mass in the vitreous or retinal layers. A systematic review of 176 cases of neurocysticercosis-related vision loss found that the retinal and intravitreal regions were involved in more than half of cases.
7PubMed Central. Vision Loss in Neurocysticercosis: A Systematic Review of Case Reports and Series Ultrasound imaging in these patients can reveal a characteristic vesicle-like mass with a bright spot inside representing the parasite’s head.
8PubMed Central. Clinical and pathological characteristics of intraocular cysticercosisPars plana cysts are another unusual variant. These form in the far peripheral retina where epithelial cell layers separate, producing smooth, oblong, fluid-filled elevations.
9PubMed Central. Case Report on Giant Pars Plana Cysts Mimicking Retinal Detachment When large, they can mimic retinal detachment on standard examination, which creates a real diagnostic dilemma. Multimodal imaging, including ultrasound biomicroscopy, can distinguish these cysts from a true detachment, and most are managed conservatively with observation alone.
10PubMed Central. Giant pars plana cysts and a diagnostic approach to peripheral retinal elevation with the assistance of multimodal imagingSymptoms and What They Feel Like
Many retinal cysts, especially those in the peripheral retina, produce no symptoms. Acquired retinoschisis is the classic example: it affects a sizable minority of older adults yet rarely threatens vision, with progressive retinal detachment occurring in only about 0.05 percent of cases.
3Cureus. Acquired Senile Retinoschisis of the Peripheral Retina Imaged by Spectral Domain Optical Coherent TomographyWhen cysts affect the macula, the situation is different. The most common complaint is blurry central vision, often described as looking through smudged glass. A more distinctive symptom is metamorphopsia, the perception that straight lines appear wavy or distorted. In a study of patients with diabetic cystoid macular edema, about half had measurable metamorphopsia when tested with specialized charts, though only about a third detected it with a standard grid test.
11Hindawi / Biomedicine Research International. Metamorphopsia Score and Central Visual Field Outcomes in Diabetic Cystoid Macular Edema This gap matters: many people with macular cysts have visual distortion they are not fully aware of, which is one reason clinicians rely on imaging rather than patient reports alone to track the condition.
Other symptoms can include a central or paracentral scotoma (a dim or blank spot in the visual field), reduced contrast sensitivity, and difficulty with color perception. In X-linked retinoschisis, children often present with reduced visual acuity that is noticed when they start school. The severity of symptoms generally tracks with the location and size of the cyst. A tiny cyst just off the foveal center might cause only subtle distortion, while a large cyst directly beneath the fovea can drop visual acuity substantially.
How Retinal Cysts Are Diagnosed
Optical coherence tomography, or OCT, is the workhorse of retinal cyst diagnosis. It produces cross-sectional images of the retina at near-microscopic resolution, allowing clinicians to see exactly where fluid has accumulated, which retinal layers are involved, and how large the cystic spaces are. OCT is also effective at distinguishing retinoschisis, where the retinal layers split apart, from retinal detachment, where the full-thickness retina separates from the tissue underneath.
12PubMed. Differentiation of degenerative retinoschisis from retinal detachment using optical coherence tomography That distinction can mean the difference between watchful waiting and emergency surgery.
Fluorescein angiography remains important for a specific reason: it reveals whether cysts are caused by vascular leakage. In classic CME, dye pools in a characteristic petal-shaped pattern in the macula during the late phases of the test. Non-vasogenic cysts, by contrast, do not show this dye leakage on angiography, which is a critical clue for determining the underlying cause.
2PubMed. Non-vasogenic cystoid maculopathiesFundus autofluorescence imaging offers a non-invasive alternative for detecting CME. The cystic spaces in the macula produce a petaloid pattern of increased autofluorescence that closely matches what is seen on angiography. In one study, this pattern was visible in all eyes when imaged at the right wavelength (488 nm), though it was essentially invisible at a longer wavelength (580 nm), which highlights the importance of the specific imaging protocol used.
13PubMed. Macular autofluorescence in eyes with cystoid macula edema, detected with 488 nm-excitation but not with 580 nm-excitation Autofluorescence is particularly useful in patients who cannot undergo the dye injection required for fluorescein angiography, though it may not work well in certain conditions like exudative age-related macular degeneration.
14Chinese Medical Journal. Characteristics of fundus autofluorescence in cystoid macular edemaTreatment Approaches for Vascular and Inflammatory Cysts
When retinal cysts result from fluid leakage driven by inflammation or vascular disease, the first-line treatments aim to shut down the leakage and reduce swelling.
Anti-VEGF injections (drugs like ranibizumab, aflibercept, and bevacizumab) are the current standard for diabetic macular edema and macular edema from retinal vein occlusion. These drugs block a protein that drives new blood vessel growth and vascular permeability, and they are delivered directly into the eye. The injections typically need to be repeated on a schedule, sometimes monthly at first, then at longer intervals as the fluid resolves.
Corticosteroids, either as eye drops, injections around the eye, or sustained-release implants placed inside the eye, are used when inflammation is a major contributor. In post-cataract CME, topical anti-inflammatory drops (a combination of a corticosteroid and a non-steroidal anti-inflammatory drug) are often the first treatment tried. Dexamethasone intravitreal implants are another option, particularly useful in cases where frequent anti-VEGF injections are impractical. In retinitis pigmentosa-associated macular edema, a network meta-analysis found that dexamethasone implants and oral carbonic anhydrase inhibitors outperformed anti-VEGF therapies at reducing retinal thickness at 3 to 4 months, and that by 12 months, topical dorzolamide and dexamethasone implants provided more sustained thickness reduction than oral alternatives.
15BMJ Open Ophthalmology. Comparative efficacy of different treatment modalities in the management of macular oedema in retinitis pigmentosa: a systematic review and network meta-analysisCarbonic anhydrase inhibitors deserve special mention because they work through a completely different mechanism than anti-inflammatory or anti-VEGF drugs. Topical dorzolamide, originally a glaucoma medication, appears to help drain fluid from the retina by affecting ion transport across the retinal pigment epithelium. In one trial, eyes receiving dorzolamide drops alongside anti-VEGF injections for diabetic macular edema showed a significantly greater decrease in retinal thickness at three months compared to injections alone.
16PubMed Central. Topical Dorzolamide as Adjunctive Treatment With Intravitreal Bevacizumab in Bilateral Diabetic Macular Edema However, this additive benefit does not always hold. A randomized trial in patients with age-related macular degeneration found that adding dorzolamide-timolol drops to anti-VEGF injections initially reduced intraretinal fluid but showed no lasting difference from placebo by about three months.
17JAMA Ophthalmology. Effect of Adjuvant Topical Dorzolamide-Timolol vs Placebo in Neovascular Age-Related Macular Degeneration: A Randomized Clinical Trial The takeaway is that adjunctive dorzolamide seems more useful in some disease contexts than others.
Surgical and Laser Options
When medications fail to resolve retinal cysts, or when the underlying anatomy demands it, surgical intervention becomes necessary. Vitrectomy, the surgical removal of the vitreous gel from inside the eye, is the most common procedure. During vitrectomy, surgeons can also peel away a thin membrane called the internal limiting membrane, which has been shown to help treat macular holes, epiretinal membranes, and persistent macular edema from diabetes or vein occlusions.
18Retina. TECHNIQUES, RATIONALE, AND OUTCOMES OF INTERNAL LIMITING MEMBRANE PEELINGLaser photocoagulation has a more targeted role. In macular retinoschisis caused by acquired optic nerve pits (small structural defects in the optic nerve head from glaucoma), barrier laser applied to the temporal margin of the nerve closed the fluid tracts in the majority of treated eyes and improved vision by about one line on the eye chart over roughly 12 months of follow-up.
19PubMed Central. Laser treatment of macular retinoschisis due to acquired optic nerve pit from glaucoma For these specific cases, laser serves as a reasonable first step before committing to vitrectomy.
What Retinal Cysts Tell Us About Surgical Outcomes
Interestingly, the cysts themselves carry prognostic information. In patients undergoing surgery for macular holes, the height of intraretinal cysts measured on preoperative OCT was significantly associated with both the likelihood of hole closure and the degree of photoreceptor damage after surgery. Larger cysts correlated with worse postoperative visual acuity and greater photoreceptor layer disruption.
20PubMed Central. Role of intraretinal cysts in the prediction of postoperative closure and photoreceptor damages of the idiopathic full-thickness macular hole This means that the presence and size of retinal cysts are not just symptoms to be treated but also useful predictors that help surgeons counsel patients about what to expect after an operation.
Retinal Cysts in Premature Infants
Retinal cysts are not limited to adults. Premature infants, particularly those with retinopathy of prematurity (ROP), frequently develop cystoid macular edema that is invisible on standard examination and only detectable with OCT. In one study, more than half of eyes with ROP had CME, and the frequency increased with disease severity: about 46 percent in the mildest stage rising to nearly 88 percent in stage 3 ROP.
21PubMed Central. Macular findings obtained by spectral domain optical coherence tomography in retinopathy of prematurity Even infants without clinically diagnosed ROP showed CME at rates around 31 percent, suggesting that prematurity itself predisposes the developing retina to cyst formation.
Another study found that CME was present in over half of premature infants who were imaged, including some whose ROP never progressed beyond the mildest stages.
22PubMed Central. Subclinical macular findings in infants screened for retinopathy of prematurity with spectral-domain optical coherence tomography In more advanced stages, OCT has also revealed retinoschisis-like splits in the inner retinal layers near the vascular-avascular junction, sometimes with vitreous traction pulling the layers apart.
23PubMed Central. Spectral-Domain OCT Findings of Retinal Vascular-Avascular Junction in Infants with Retinopathy of Prematurity The long-term visual consequences of these early cysts are still being studied, but their high prevalence has strengthened the case for routine OCT screening in premature infants, not just traditional indirect ophthalmoscopy.
Gene Therapy for Inherited Retinal Cysts
X-linked retinoschisis has become one of the test cases for retinal gene therapy, in part because it is caused by mutations in a single gene (RS1) and produces clearly measurable structural changes on OCT. Multiple early-phase clinical trials have evaluated adeno-associated virus (AAV) vectors designed to deliver a functional copy of the RS1 gene directly to the retina. One trial used an intravitreal injection approach with an AAV2 vector to deliver the retinoschisin gene to affected patients.
24PubMed. Intravitreal Delivery of rAAV2tYF-CB-hRS1 Vector for Gene Augmentation Therapy in Patients with X-Linked Retinoschisis: 1-Year Clinical Results A separate trial used an AAV8 vector via intravitreal injection and focused on safety and tolerability.
25Molecular Therapy. Phase I/IIa Trial of Intravitreal AAV8-RS1 Gene Therapy for X-Linked RetinoschisisMore recently, a trial tested a subretinal injection route, placing the vector under the retina in patients aged 5 to 18.
26PubMed. Subretinal Gene Therapy for X-Linked Retinoschisis The subretinal approach delivers the gene payload closer to the photoreceptors, which is where retinoschisin protein is needed. These trials are still in early stages and are primarily designed to evaluate safety, but the fact that multiple groups are pursuing gene therapy for this condition reflects genuine optimism that replacing the faulty RS1 gene could prevent or reduce the foveal cyst formation that robs young males of central vision. No gene therapy for retinoschisis has received regulatory approval yet, so for now, management remains supportive: carbonic anhydrase inhibitors to reduce cyst fluid where possible, and monitoring for complications like vitreous hemorrhage or retinal detachment.
Artificial Intelligence and the Future of Cyst Detection
Detecting and measuring retinal cysts on OCT is a task that lends itself well to automation. Researchers have developed deep learning models, including U-Net architectures, that can identify and quantify cystic fluid regions in OCT scans with results that closely match expert manual segmentation.
27International Journal of Imaging Systems and Technology. Deep learning based automated detection of intraretinal cystoid fluid Other approaches have used hidden Markov models to rapidly flag OCT scans that contain cysts, aiming to speed up the workflow in busy retina clinics.
28Europe PMC. Cyst identification in retinal optical coherence tomography images using hidden Markov modelThe practical promise is screening at scale. If an algorithm can reliably identify cystic changes on OCT, then high-volume screening programs for diabetic eye disease or retinopathy of prematurity could flag patients who need specialist review without requiring a retina specialist to personally review every scan. This is particularly relevant in settings where specialist access is limited. The technology is not yet deployed as a standalone diagnostic tool, but the accuracy benchmarks being achieved suggest it is moving steadily in that direction.