wet macular degeneration

wet macular degeneration
Name	Wet macular degeneration
Synonyms	Neovascular age-related macular degeneration, exudative age-related macular degeneration
Field	Ophthalmology
Symptoms	Central vision loss, visual distortion, blurred vision
Complications	Retinal detachment, macular scarring
Onset	Typically after age 50
Duration	Chronic
Causes	Abnormal blood vessel growth under the retina
Risks	Advanced age, tobacco use, Hypertension, Cardiovascular disease
Diagnosis	Fundus photography, Optical coherence tomography, Fluorescein angiography
Differential	Diabetic retinopathy, Retinal vein occlusion, Polypoidal choroidal vasculopathy
Treatment	Anti-VEGF therapy, Photodynamic therapy
Medication	Ranibizumab, Aflibercept, Bevacizumab
Prognosis	Variable; treatment can stabilize or improve vision
Frequency	~10-15% of all age-related macular degeneration cases

wet macular degeneration. Wet macular degeneration, clinically termed neovascular age-related macular degeneration, is an advanced form of macular disease characterized by the pathological growth of new, fragile blood vessels from the choroid into the subretinal space. This process, known as choroidal neovascularization, leads to leakage of fluid, lipids, and blood, which damages the delicate photoreceptor cells of the macula and causes rapid, often severe central vision loss. It represents a smaller but more aggressive subset of age-related macular degeneration compared to its dry counterpart, and is a leading cause of irreversible blindness in older populations in the developed world.

Pathophysiology

The primary pathological event is the development of choroidal neovascularization, an aberrant angiogenesis driven by an imbalance of growth factors within the Bruch's membrane and retinal pigment epithelium complex. A key mediator is vascular endothelial growth factor, whose overexpression is stimulated by local hypoxia and inflammatory deposits known as drusen. These new vessels, originating from the choroidal circulation, breach Bruch's membrane and form a vascular membrane beneath the retina or retinal pigment epithelium. The vessels are inherently leaky, leading to exudation of serous fluid, hemorrhage, and eventual fibrous scarring, which disrupts the normal architecture of the photoreceptor cell layer and supporting tissues. This process is distinct from the non-neovascular, atrophic progression seen in geographic atrophy.

Signs and symptoms

Patients typically report a relatively sudden onset of central visual disturbances. Key symptoms include metamorphopsia, where straight lines appear wavy or distorted, a symptom often assessed using an Amsler grid. There is a noticeable blurring or dark spot in the central visual field, known as a central scotoma, which impairs tasks like reading, driving, and facial recognition. Patients may also report reduced contrast sensitivity and, in cases of significant hemorrhage, a sudden loss of vision. Unlike peripheral retinal diseases, peripheral vision usually remains intact. Symptoms often progress more rapidly than in the dry form, prompting urgent ophthalmological evaluation.

Diagnosis

Diagnosis relies on a combination of clinical examination and advanced retinal imaging. Following a comprehensive eye exam including visual acuity testing, the cornerstone of diagnosis is optical coherence tomography, which provides high-resolution cross-sectional images to detect subretinal fluid, intraretinal edema, and the neovascular membrane itself. Fluorescein angiography involves intravenous injection of dye to dynamically visualize the leakage and precise structure of the abnormal vessels. Indocyanine green angiography may be used concurrently to better delineate the choroidal vasculature, particularly in cases of polypoidal choroidal vasculopathy. These imaging modalities are often complemented by fundus photography to document the appearance of hemorrhages, exudates, and fluid.

Management

The standard of care is intravitreal injection of anti-VEGF therapy, which blocks the vascular endothelial growth factor protein to inhibit angiogenesis and reduce vascular permeability. Commonly used agents include ranibizumab, aflibercept, and bevacizumab. Treatment involves an initial series of monthly injections, often followed by a personalized maintenance regimen based on disease activity as monitored by optical coherence tomography. Historically, photodynamic therapy with verteporfin was used to selectively occlude abnormal vessels. In certain cases, combination therapies or alternative approaches like argon laser photocoagulation may be considered, though these are less common. Management is typically overseen by a retina specialist in a clinical setting like the National Eye Institute-affiliated centers.

Epidemiology

Wet macular degeneration is a disease predominantly of older adults, with incidence increasing dramatically after age 60. It is a leading cause of severe vision loss in populations of European descent in countries like the United States and those within the European Union. While it accounts for only approximately 10-15% of all age-related macular degeneration cases, it is responsible for a disproportionate share of severe legal blindness from the disease. Major risk factors include advanced age, a positive family history, smoking—which is the most significant modifiable risk factor—hypertension, and genetic polymorphisms such as those in the CFH and ARMS2 genes. Women and individuals with light iris color may also have a higher prevalence.

Prognosis

The natural history of untreated wet macular degeneration is generally poor, with most patients experiencing significant central vision loss within two years. However, the advent of anti-VEGF therapy has dramatically altered the prognosis, with the majority of patients now achieving stabilization of vision and a substantial proportion gaining meaningful visual acuity improvement. Final visual outcomes depend on multiple factors including the specific lesion characteristics, the timing of treatment initiation, and patient adherence to the injection regimen. Despite treatment, many patients develop some degree of permanent central scotoma or macular scarring. Ongoing clinical trials, such as those coordinated by the National Institutes of Health, continue to investigate new therapeutic targets and treatment strategies to further improve long-term visual outcomes and quality of life.

Category:Ophthalmology Category:Retinal disorders Category:Age-related diseases