Pseudodrusen are small, yellowish-white deposits that gather within the retina, the light-sensitive tissue at the back of the eye. Often identified during routine examinations in older adults, these accumulations relate to the health of the macula, the part of the retina responsible for sharp, detailed vision. Their presence signifies changes occurring within the deeper layers of the retina. The identification of pseudodrusen prompts a closer look, as they are an indicator of underlying processes that can affect vision over time.
Distinguishing Pseudodrusen from Drusen
A primary difference between pseudodrusen and the more commonly known drusen is their precise location within the retina’s layers. Drusen form underneath the retinal pigment epithelium (RPE), a layer that nourishes the retina. In contrast, pseudodrusen, also called subretinal drusenoid deposits, accumulate on top of the RPE, positioning them directly beneath the light-sensing photoreceptor cells.
This difference in location also gives them a distinct appearance during an eye exam. Ophthalmologists see drusen as yellowish spots with well-defined borders. Pseudodrusen appear as paler, grayish-white, or yellowish lesions with indistinct, soft borders. They frequently coalesce into a net-like or reticular pattern across the macula, a characteristic that led to the alternative name “reticular drusen.”
While both types of deposits are composed of cellular waste products, including proteins and lipids, their composition and structure differ. The specific location of pseudodrusen suggests they are formed by different biological pathways than drusen.
The Link to Advanced Macular Degeneration
The presence of pseudodrusen is an indicator for the progression to late-stage age-related macular degeneration (AMD). Individuals with pseudodrusen have a much higher risk of their condition advancing compared to those who only have conventional drusen. This elevated risk changes the prognosis and management plan for the patient.
These deposits are strongly associated with the development of both forms of advanced AMD. They increase the likelihood of geographic atrophy (GA), the “dry” form where retinal cells die off, leading to permanent blind spots. They are also linked to a greater risk of choroidal neovascularization (CNV), the “wet” form characterized by fragile, abnormal blood vessels that leak fluid and blood into the retina, causing rapid vision loss.
The mechanism behind this increased risk is tied to their location. By forming above the RPE, pseudodrusen may disrupt the functional relationship between this supportive cell layer and the overlying photoreceptors. This interference can impair nutrient transport and waste clearing, accelerating the degenerative processes that lead to cell death in GA or trigger the abnormal vessel growth in wet AMD. The deposits can also regress, but this is often followed by atrophy of the outer retina.
Diagnosis and Monitoring Strategies
Detecting pseudodrusen requires advanced imaging technologies that can visualize the distinct layers of the retina. While they may be suspected during a clinical exam, the definitive diagnosis is made with optical coherence tomography (OCT). This non-invasive technology provides a high-resolution, cross-sectional image of the retina, allowing a specialist to see the exact location of the deposits and confirm they are situated above the RPE.
Other imaging methods supplement the diagnosis. Fundus autofluorescence (FAF) is a technique that assesses the health of the RPE and can show characteristic patterns when pseudodrusen are present. Color fundus photography, especially when using different light filters like blue light, can help reveal their faint, reticular pattern. These tools provide a comprehensive picture of the deposits.
Once diagnosed, management focuses on monitoring for progression toward advanced AMD. This involves more frequent eye exams to track changes with repeated imaging. Patients are also instructed on how to use an Amsler grid at home to self-monitor for new or worsening visual distortions. For individuals whose overall AMD status is classified as intermediate, AREDS2 supplements are commonly recommended to help lower the risk of progression to late-stage disease.