Obliviousness, as the name suggests, is a condition in which the eye sees but pretends not to see. In the outpatient clinic, doctors often come across this type of patient, he/she will feel unable to see, unable to recognize commonly used things, or even unable to see the objects around him/her. When the patient is busy wearing eyeglasses or after an eye clinic examination, he/she finds that his/her vision is normal and there is no problem with his/her eyes. At this point, it is necessary to be alert to the possibility of a specific type of dementia (scientific name: Alzheimer’s disease) known as posterior cortical atrophy. Posterior Cortical Atrophy (PCA) is a chronic progressive neurodegenerative disease that begins with visual symptoms, which are mainly characterized by difficulty seeing and finding objects. This “invisible” symptom is actually caused by the atrophy of the parietal lobe, which is related to visual space, and the occipital lobe, which is related to visual cognition, in the back of the brain, resulting in visual agnosia. About 85% of the patients have the visual variant of Alzheimer’s disease, and the onset of the disease is early, mostly between the ages of 50 and 65. However, with eye problems, patients will first go to the eye clinic for examination without finding any abnormality, and will not go to the neurology department until the disease has worsened to the extent that it affects memory and other cognitive functions, by which time the best time for treatment may have been missed. These patients often complain that they tend to hit the rearview mirror when driving, parking has become difficult, they don’t know how far to go up and down stairs, and they can’t find the next paragraph in a newspaper. This is all because the patient has lost the ability to recognize the spatial position of objects and the spatial relationship between objects. However, some patients complain that they can’t see, but they can see the partial appearance of a picture, but can’t recognize the whole appearance, similar to “only see the trees, not see the forest”. Some patients even tell their doctors: “The faces of the people in front of me all look the same, and I can’t even recognize common things such as key chains, apples, and hot water bottles on the table, but I can recognize them with the help of my sense of touch or hearing”. This may be due to a loss of visual perception, which may include face disorientation, inability to distinguish between men and women, and inability to recognize one’s own face in a mirror from several others. It also includes object disorientation, in which the patient is unable to classify a variety of objects according to their form, material, color, or purpose when they are placed together. As well as color dyscrasia, some patients are unable to distinguish between colors that they used to be able to distinguish correctly. Difficulty with legibility or clumsiness in writing, difficulty with arithmetic, and in distinguishing left from right are also common symptoms of the disease. If the patient does not receive proper treatment during this period, the symptoms may get progressively worse over a period of 2-3 years. For example, memory loss, repetition of questions, and forgetting appointments occur. Some patients also experience poor speech expression and difficulty finding words. In the later stages of the disease, full-blown dementia is manifested, and it is difficult to distinguish this period from typical Alzheimer’s disease. The current treatment of posterior cortical atrophy is also an integrated and comprehensive approach that includes pharmacologic treatment of the underlying cause, compensatory approaches, cognitive rehabilitation, and treatment of its complications. Pharmacologic intervention in the early stages of the disease can relieve symptoms and improve quality of life. At the same time, doctors can also help patients with rehabilitation training, such as recognizing commonly used, essential, and functionally specific objects through repeated practice; providing non-verbal motor-sensory guidance: for example, recognizing a comb by combing the hair; asking patients to draw a clock, a house, or a map to show the way home; encouraging patients to use their senses of touch and hearing more often in their lives; and labeling objects, and so on. If you or your family members experience any of the above symptoms and the eye examination shows normal, please visit the Memory Clinic of the Department of Neurology in a timely manner. Early diagnosis and treatment can be helped by tests such as memory scales, blood tests and imaging.