Vision

Dry eye disease is a chronic condition estimated to affect around 360 million people. Common symptoms include uncomfortable, red, scratchy or irritated eyes. Anecdotal claims are that laughter therapy alleviates depression, anxiety, stress, and chronic pain, while strengthening immune function but if you have clinical depression, please don't limit yourself to people saying you need to smile more and get scientific help. Laughter therapy for dry eye disease is a much less risky proposition. Scholars in China and the UK had 283 participants aged 18-45 years (average age 29; 74%…

To adult audiences in 1977, "Star Wars" was the most realistic special effects they had ever witnessed while to younger people of today, the defects are obvious. Some of that is due to better technology, a cheap TV has better clarity and resolution that an IMAX screen a generation ago, but some of it is that they are trained to see better. Yet as with .MP3s and sound fidelity, tablets and phones may be setting progress back in vision. We have been trained to enjoy lower quality sound and a new study says that pixels and rectangles are affecting how we see oblique angles of things like tree…

Sixteen-year-old Karl is seen for the first time in my optometry practice. He was referred to me for a fluctuating vision problem. During his examination, I saw signs suggesting he may have diabetes, which could have explained the fluctuating vision. This suspicion became a reality when his family doctor confirmed the diagnosis. Karl’s world was turned upside down. As an optometrist, I invite you to dive into a reality that should concern us all. What is diabetes? Diabetes is an insidious disease. Its symptoms (thirst, need to urinate often, fatigue, weight loss, darker skin areas on the neck…

Multimodal adaptive optics imaging has revealed photoreceptor and retinal pigment epithelium relationships in eyes with vitelliform macular dystrophy.  Vitelliform macular dystrophy (VMD) is an inherited genetic disease that causes progressive vision loss through degeneration of the light-sensing retina. Genes implicated in VMD include BEST1, PRPH2, IMPG1, and IMPG2. Depending on the gene and mutation, age of onset and severity vary widely. All forms of the disease have in common a lesion in the central retina (macula) that looks like an egg yolk and is a build-up of toxic fatty material…

Dyslexia is well-known to impact reading ability but it has been unclear which brain processes are affected by the condition. Whether dyslexia is, at its core, a visual processing disorder is hotly debated among researchers. With reading and writing a key challenge among children with dyslexia, increasing understanding of its effects on the brain might improve existing interventions.  A new study combined visual processing and brain activity in dyslexia and found that children with it are slower to process visual information. The experiment involved children ages six to 14 and asked them…

Some people believe that marijuana can be medical but almost no marijuana users think it impairs their vision. Though over 90 percent of users believe that cannabis has no effect on their vision, or perhaps a slight effect, smoking cannabis significantly alters key visual functions such as visual acuity, contrast sensitivity, three-dimensional vision (stereopsis), the ability to focus, and glare sensitivity, according to research. The work was led by Drs. Carolina Ortiz Herrera and Rosario González Anera from la Universidad de Granada, who that cannabis use is on the rise despite being an…

A new paper finds that widely available retinal imaging techniques may help reveal more about brain disease and monitor treatment efficacy, including a currently untreatable form of childhood-onset dementia, Sanfilippo syndrome. Sanfilippo syndrome is one of a group of about 70 inherited conditions which collectively affect 1 in 2800 children in Australia, and is more common than cystic fibrosis and better known diseases. Around the world 700,000 children and young people are living with childhood dementia. The researchers studied Sanfilippo syndrome in mouse models, discovering for the first…

With racial tension erupting again, parents may be wondering the appropriate age to discuss what kids see in news accounts or in protests at sporting events.  Psychologists believe that some infants are aware of race and children are capable of thinking about all sorts of complex topics at a very young age. They must, because they see older, bigger people doing things that may seem almost magical, and it becomes important to make sense of their world and so they will come up with their own ideas about how things work. But if they only see news on television, with two sides rioting and…

One symptom of post-traumatic stress disorder (PTSD) is intrusive visual reminders of a traumatic event. New research in Current Biology finds that the brain uses similar visual areas for mental imagery and vision, but it uses low-level visual areas less precisely with mental imagery than with vision. Mental imagery is in some ways similar to vision, but obviously not identical. The fuzzy dream-like state of imagery helps us to distinguish between our waking and dreaming moments. In people with PTSD, invasive images of traumatic events can become debilitating and feel like reality. If we…

Sildenafil (viagra) is used to treat erectile dysfunction and is safe, with known side effects, but a few people have experienced light sensitivity and color vision impairment at the highest recommended dose. That doesn't mean men who need it should stop taking it, the psychological consequences of erectile dysfunction are of more concern than side effects, which can include headache and blurred vision that disappear quickly. These occur because sildenafil was originally developed as a treatment for high blood pressure, and it also dilates blood vessels and relaxes smooth muscle in…