Dear Doctor: I read that a girl went blind in one eye after playing video games on her phone for an entire day. Is this even possible? Should I be worried about my kids, who are video game addicts?

Dear Reader: You’re referring to a news story from China that made headlines a few years ago. The woman in question, who was 21 at the time, reportedly spent an entire day playing an online video game and suddenly lost the vision in her right eye.

Doctors diagnosed her with retinal artery occlusion, a blockage in the main vessel that supplies blood to the retina. The retina is the layer of light-sensitive tissues at the back of the eye that translate the energy from incoming light into impulses. These impulses then travel via the optic nerve to the brain, where they are interpreted as visual images.

When the retinal artery becomes blocked, oxygen-rich blood can’t reach the retina. This can result in cell death and vision loss. The speed at which the cells of the retina die and the extent of the damage depends on the degree of arterial blockage and how long it lasts.

Retinal artery occlusion usually occurs in people 60 and older, and it is slightly more common in men. The cause of the blockage is usually a blood clot or an embolus, which is a bit of foreign matter in the bloodstream, such as an air bubble or a bit of fatty deposit. Risk factors for the condition include high blood pressure, diabetes, heart arrhythmias, carotid artery disease, the use of oral contraceptives, faulty heart valves and blood platelet abnormalities, to name just a few. It is not known which specific risk factors applied to the woman in the story.

At this time, there are no reliable treatments for retinal artery occlusion. Most involve procedures to somehow dilate the affected artery, dislodge the blockage and restore normal blood flow.

Regarding the claim that the young woman’s marathon gaming session caused the arterial blockage, there turns out to be a bit more to the story. With an estimated 2.3 billion-with-a-B people worldwide regularly playing online games, addiction has become a serious concern. In China, authorities have identified online gaming addiction as a public health crisis. Stories of gamers forgetting to eat, skipping school, getting fired from work and even wearing disposable diapers in the pursuit of their online gaming passions abound.

The patient in the news story had been playing a hugely popular game known as Honor of Kings. The parent company claims to have more than 80 million daily active users, and 200 million players per month. Some observers believe that, despite the lack of an established medical connection between extreme eye strain and retinal artery occlusion, authorities have used the patient’s medical emergency as a vivid cautionary tale to fellow gamers.

When it comes to your own kids, it’s highly unlikely that their gaming habits will physically blind them. However, any time a single activity takes precedence over daily activities and other life interests, we believe there is cause for concern.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I recently read about advance directives that deal only with dementia. Is there some benefit to those over the more traditional directives? If so, how do I go about creating one?

Dear Reader: Most of us are probably familiar with the concept of the advance health care directive, which is sometimes referred to as a living will. It’s a legal document that outlines your specific wishes regarding medical and health care decisions, including end-of-life care, in the event that you are unable to do so.

But with the number of people living with dementia expected to nearly triple worldwide by 2050, some in the medical community now see a need to expand the scope of the advance directive. This was formally addressed in an opinion piece in the December 2017 issue of the Journal of the American Medical Association, where the authors made a case for crafting an advance directive specifically for dementia.

Their thinking is that because dementia is a disease that progresses in stages, a person’s health care goals should similarly follow a gradual trajectory. Cognitive decline often occurs over the course of years or even decades. That means that standard advance health care directives, which dictate decision-making in times of crisis, aren’t always the right fit. With a dementia-specific advance directive, the individual addresses a range of questions based on how cognitive decline typically progresses. Not only does this allow them to make specific choices regarding health care and quality of life, it frees family members from difficult decisions and painful arguments. This includes decisions about undergoing a range of medical tests, medical care and end-of-life interventions.

The dementia-specific advance directive proposed by the authors of the JAMA essay divides cognitive decline into three phases -- mild, moderate and severe. The individual indicates his or her health care goals for each phase of dementia.

These goals are further broken into four stages. The first stage is living as long as possible, which includes accepting all medical interventions, including restarting the heart should it stop beating. The second stage is to receive certain types of medical care but to decline efforts to restart the heart. The third stage indicates a person’s wishes to receive limited medical care, and only in the place where they are living, not in a hospital. The final stage is a request for palliative care, which means addressing only the comfort of the patient, with no efforts to prolong life.

Questions about treatment like antibiotics, the placement of a pacemaker, the use of dialysis, blood transfusions, respirators or feeding tubes can all be addressed within the framework of the document. The authors stress that this type of advance directive must be filled out before any signs of dementia have presented themselves, and the document should be revisited regularly for amendments and updates.

As with all advance directives, it’s important to have these documents drafted by an attorney so they will be legal in the individual’s state. And it’s vital to have copies readily available for when they are needed.

To learn more, or to create your own document, visit dementia-directive.org.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I’m a tea drinker, and I like it best when it’s steaming hot. My sister says drinking liquids that hot is bad for you, and that they can cause cancer. Is she right? Should I be worried?

Dear Reader: About three years ago, a report that classified drinking very hot liquids as a probable carcinogen made headlines around the world. The warning came from the International Agency for Research on Cancer, an arm of the World Health Organization. The finding arose from several observational studies that linked drinking very hot liquids to an increased risk of cancer of the esophagus.

The most common hot beverage in those studies was mate, a tea widely consumed in South America, Africa and Asia. Mate is traditionally served quite hot, about 149 degrees Fahrenheit, which is scalding. Drinking the same liquids in the studies at cooler or cold temperatures was not associated with elevated cancer risk.

The report received some pushback, which included the criticism that the studies it cited did not include precise temperature data of the drinks consumed by the participants.

Since then, findings from two newer studies have made similar connections between very hot beverages and esophageal cancer. In a report published last year in the Annals of Internal Medicine, the increase in cancer risk was seen mostly in drinkers of very hot tea who also smoked or drank alcohol.

The study analyzed the tea consumption habits of 450,000 Chinese adults over the course of almost 10 years. When consumption of very hot tea was combined with smoking and drinking, cancer risk was 2 to 5 times greater. The alcohol use associated with the increased risk was one beer, glass of wine or shot of hard liquor per day. Smoking was defined as one or more cigarettes per day.

Another study of 50,000 adults in Iran, published in the International Journal of Cancer in March, found that drinking two large cups of tea per day hotter than 140 degrees Fahrenheit resulted in almost double the cancer risk.

Cancer of the esophagus, which is the eighth most common cancer worldwide, is responsible for 500,000 deaths per year. Researchers suspect that very hot liquids irritate or damage the lining of the esophagus. This type of repeated injury likely leads to increased inflammation and leaves the delicate tissues vulnerable to damage from other potential carcinogens, including those contained in tobacco products and alcohol. Tobacco and alcohol use, acid reflux and being over 55 are also considered to be risk factors for cancer of the esophagus. This type of cancer is more common in men than in women.

When it comes to preferences for beverage temperature, Americans and Europeans tend to be more moderate than tea drinkers in Asia, South America and Africa. Considering that 80 percent of tea in the United States is consumed as iced tea, we suspect that added sugar may be as much of a health concern here as the temperatures of hot tea. Still, we think it makes sense to opt for cooler temperatures with any hot beverages in order to protect the hard-working tissues of the esophagus.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)