Phantom Images in Vision: Causes and Insights - Ophthalmology

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Phantom images, or afterimages, can be a perplexing phenomenon for many individuals experiencing visual disturbances. The situation you described, where you perceive faint white projections or shadows around objects, can be attributed to several underlying mechanisms related to the functioning of the visual system.

Firstly, afterimages are a normal physiological response of the retina and the visual cortex. When you look at a bright object for an extended period and then shift your gaze, the photoreceptors in your retina (specifically, the cones responsible for color vision) can continue to send signals to the brain even after the stimulus is removed. This can create a lingering perception of the object, often seen as a ghostly image or shadow. This phenomenon is particularly pronounced in high-contrast situations, such as viewing a bright clock against a dark wall, which may explain the white projections you see.

In your case, the presence of multiple visual disturbances, including the perception of shadows or outlines around objects, could also be influenced by your existing retinal conditions, such as the "多反視網膜病變" (multiple retinal lesions) and "飛紋症" (floaters). These conditions can disrupt the normal processing of visual information, leading to unusual visual experiences. The interaction between these conditions and the way your brain interprets visual signals can result in the perception of phantom images.

Moreover, the phenomenon you described, where the images disappear upon quick movements or changes in focus, suggests that the visual system is attempting to recalibrate itself. This is a normal response as the brain continuously processes visual input and adjusts to changes in the environment. The transient nature of these projections indicates that they are likely not a cause for concern, especially if they do not persist or worsen over time.

Regarding the specific visual experiences you mentioned, such as the perception of black edges or outlines around objects, this could also be related to the way your visual system compensates for contrast and brightness. The brain often enhances edges and boundaries to help distinguish objects from their backgrounds, which can sometimes lead to the perception of additional outlines or shadows.

It's important to note that while these phenomena can be benign, they can also be indicative of underlying retinal or neurological issues, especially given your history of retinal disease. Therefore, ongoing monitoring and regular check-ups with your ophthalmologist are crucial. The tests you mentioned, such as EOG (electrooculography) and ERG (electroretinography), are designed to assess the electrical activity of the retina and the eye's ability to respond to light, which can provide valuable insights into the health of your visual system.

As for your concerns about potential vision loss, it's understandable to feel anxious. However, many visual disturbances can be managed or treated effectively, especially when caught early. Medications like Mthycobal (Vitamin B12) can support nerve health, which is beneficial for overall visual function.
In conclusion, while phantom images can be disconcerting, they are often a normal part of visual perception, especially in individuals with existing eye conditions. Continued collaboration with your healthcare provider and adherence to recommended examinations will help ensure that any significant issues are identified and addressed promptly. If you experience any sudden changes in your vision or new symptoms, do not hesitate to seek immediate medical attention.