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  • Study Links Weight-Loss Drug to Rare Eye Condition

    Study Links Weight-Loss Drug to Rare Eye Condition

    According to a new study, the active ingredient semaglutide in the coveted weight loss injection Wegovy and the diabetes medication Ozempic from Novo Nordisk may be linked to a dangerous eye disease. After analyzing data from over 16,800 patients at a large eye clinic in Boston, an international team of researchers concluded that people taking semaglutide have a four-fold increased risk of non-arteritic anterior ischemic optic neuropathy (nAION).

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    This eye condition results in sudden unilateral loss of vision due to a circulatory disorder of the optic nerve.

    Diabetics have an increased risk for this disease. According to the study published in the journal “JAMA Ophthalmology,” among the patients, there were 710 people with type 2 diabetes and 979 people with overweight or obesity who were treated with either semaglutide or another medication. During the three-year observation period, the risk of a nAION diagnosis for diabetics taking semaglutide was 8.9 percent, compared to a risk of 1.8 percent when using other antidiabetic drugs.

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    For overweight and obese individuals in the semaglutide group, the risk was 6.7 percent, compared to 0.8 percent in the group taking other weight-reduction medications.
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    The scientists emphasized that this does not prove that semaglutide is the reason for this increased risk. However, further investigation of the connection is necessary. Medical professor Graham McGeown from Queen’s University in Belfast explained that while the study had a high quality level, the study authors themselves had pointed out important weaknesses.

    Cause and Effect Unclear

    The data doesn’t disclose the rationale behind administering the medications. A factor could be that those treated with semaglutide had previously been more severely ill with diabetes than the other subjects. Additionally, there are doubts about how representative the group of patients is for the US population. The semaglutide group was, on average, older than the others. This could explain the NAION risk, and people of African American descent are also considered disproportionately at risk.

    Larger studies would need to verify the connection. “Given the rapid increase in the use of semaglutide and its potential approval for a range of problems other than obesity and type 2 diabetes, this question deserves further investigation,” McGeown stated.

    Semaglutide belongs to the class of so-called GLP-1 agonists, which lower blood sugar levels and reduce appetite. Ozempic and Wegovy helped the Danish pharmaceutical manufacturer Novo Nordisk achieve record sales and become Europe’s most valuable publicly listed company. Novo stated that patient safety is the company’s highest priority. “We take all reports of adverse events associated with the use of our medicines very seriously.” Overall, however, the published data are not sufficient to establish a causal relationship between the use of GLP-agonists and nAION. There are also important methodological limitations to the study that must be considered when interpreting the results.

    nAION occurs in about two to ten cases per 100,000 people, making it the second most common cause of blindness due to optic nerve damage. A previous study had already shown that semaglutide can worsen diabetic retinopathy, a disease of the retina. Therefore, specialists recommend an eye examination before and during semaglutide use.

  • Does Reading in the Dark Hurt Your Eyes?

    Does Reading in the Dark Hurt Your Eyes?

    If you continue to read in the dark, your eyes will be permanently damaged. This reprimand was most likely shared with many people when they were children. But should a parent even be concerned about anything like this? Could reading in inadequate light truly cause nearsightedness or other refractive errors?

    People believed that genetics were the primary factor in determining nearsightedness and that environmental factors had only a very small role. This belief existed as late as fifty years ago. Experiments conducted with monkeys and birds showed, however, that this kind of impaired eyesight could be purposefully created. 

    For instance, hens were outfitted with specially designed matte glasses that obscured their eyesight. As a direct consequence of this, the chicks’ eyeballs started to grow. Because of this, the picture that was created by the eye lens was no longer projected precisely onto the retina, which caused the chicks to develop nearsightedness.

    Vision Impairment Leads to an Increase in Eyeball Size

    The trials demonstrated that it is necessary to have fine details on the retina in focus, to avoid excessive expansion of the eyeball. This also applies to human beings. For instance, if a child’s eye lens is cloudy when they are young, there is a chance that they may develop nearsightedness as they become older. This is because the eye will attempt to remedy the apparent farsightedness.

    But a lack of light may also cause this effect. When scientists placed a form of sunglasses on chicks, they forced them to live in perpetual low light. They did this so they could study the impact of a lack of light. These chickens also acquired myopia, but to a far lower degree than their contemporaries who wore matte glasses.

    Myopia Is Spreading Like Wildfire Among the Student Population

    The question is, what does this imply for humans? Does reading in the dark corner of the room or beneath the blankets cause long-term harm to the eyes? The consensus is that “no” is the most appropriate response to this question. Because several studies have shown that the prevalence of myopia, or nearsightedness, has substantially grown over the last few years and decades, particularly among students.

    There is a strong connection between the total number of hours spent in education and impaired vision. For instance, there has been a substantial increase in the number of youngsters suffering from myopia in Asia as the education levels in that region increased and children spent more time in school and on their homework.

    Dopamine Triggered by Sunlight

    But to what extent is reading the fault of impaired vision like myopia? The results are inconclusive. But experts believe it’s more probable that the culprit is youngsters spending more time sitting at home than the amount of time they spend reading. Recent research has indicated that encouraging youngsters to spend more time outside may help to reduce the risk of nearsightedness in childhood. 

    Because exposure to strong sunlight stimulates the neurotransmitter dopamine to be produced in the eye. This, in turn, stops the eyeball from expanding to an unhealthy degree. If youngsters spend more time outside and less time inside, there will be less of a negative impact.

    People From Cities vs. Rural Areas

    According to the study, this connection also explains why children living in cities have a higher risk of having nearsightedness than children living in rural regions: children living in cities spend less time playing outdoors than their counterparts living in rural areas.

    There are experimental initiatives already underway in China and Singapore to encourage families to participate in more outdoor leisure activities. It is safe to say that bookworms who spend more time outdoors won’t be causing any damage to their eyes.

    The findings of the study indicate that there is strong evidence that this may at least partly compensate for the strain that is placed on the eyes as a result of close-up vision.

  • Why Do You Have to Close Your Eyes When You Sneeze?

    Why Do You Have to Close Your Eyes When You Sneeze?

    Every time you sneeze, it’s like an explosion with high-pressure air shooting out of your mouth and nose with droplets and other mucus fluids. Muscles in your face stiffen up without your knowledge, and you find yourself temporarily closing your eyelids. But for what purpose do you close your eyes when you sneeze?

    Maybe it’s to keep you safe from the bacteria and mucous that are released during the sneeze. Or, can hiding your face protect your eyes from the internal pressure that may cause them to bulge and be permanently damaged? Both of those renditions are widely shared on the Web. It’s widely known that you can’t keep your eyes open when sneezing since it’s a reflex. Does this hold water, though?

    Not a true reflex

    The act of sneezing does not constitute a true reflex. The sneeze stimulus is more nuanced and is not under pure spinal-cord control. Foreign objects in the nose, infections, and allergies are only a few of the many causes of sneezing.

    Those pesky irritants on the nasal mucosa are shot out the window as the air is released at a speed of around 90 mph (150 kph), the head is jerked forward, and we hear “explosion” sounds. However, closing your eyes as a result of a sneeze is not always a reflex. There are actually recordings of individuals sneezing with their eyes open.

    How does it work?

    There are two widely shared theories for why people have to automatically shut their eyes when they sneeze. To start, the whole body, not just the chest and breathing muscles, tenses up when you sneeze. That is why a drop of pee or gas may be released during a sneeze.

    The face and the eyes in particular are tense during a sneeze. When you tense up, the muscles around your eyes shut your lids. 

    But the idea that this response is meant to shield the eyes from the resulting higher pressure is nonsense.

    Nerve network joins nose and eyes

    However, there is a nerve that runs between the eyes and the nose. The nasociliary nerve divides into two branches, one of which travels to the top of the nose and the other to the eyelids and the sclera (whites of the eyes). This is because there is a tight relationship between the nose and the eye. Sneezing is an example of an inflammatory response in the eye region, which may also be caused by irritation to the nerve branch that leads to the nose.

    Some individuals, for instance, may sneeze in response to really bright light, demonstrating the intimate relationship between the eye and the nose. This is due to the proximity of the optic nerve to a branch of the nasociliary nerve. The sun’s rays stimulate the optic nerve, producing an electric current. When this current goes down the nerve fiber and across to the next nerve, it makes you sneeze.

    In any event, shutting your eyes when you sneeze makes biological sense. One of the first forms of self-defense is the simple act of closing your eyes. All painful stimuli cause you to shut your eyes automatically. Our ancestors knew this organ was critical to their existence; therefore, they guarded it instinctually.

  • What Makes Glass Transparent?

    What Makes Glass Transparent?

  • Why Can’t You See Your Own Eye Movements?

    Why Can’t You See Your Own Eye Movements?

    Even when we believe we are focusing on a single target, our eyes are actually moving rapidly from one location to the next. This occurs even when our attention is focused on a single place. When we move our heads from side to side, our eyes jerk very quickly and shake violently. This also occurs when we alter the direction in which we are looking. We, on the other hand, are so used to these unpredictable eye movements that we rarely perceive them at all. Then, what might be the cause of this?

    Jerky eye movements

    It is a straightforward experiment in which you start by focusing on your right eye while standing in front of a mirror. After then, you allow your sight to slowly shift to your left eye. Whatever you do, you do not see your own eyes moving. Observers have been able to show that our eyes don’t stay still when we move our focus from one place to another.

    This is because of a combination of two factors: first, the motions of our eyes, and second, the method by which our brain interprets those movements. Saccades are short, jerky, and, most crucially, very rapid motions that occur when the eyes move. Saccades are the technical term for these types of eye movements. When we allow our focus to wander, the movement of our eyes is not equal. Instead, our attention skips about from one thing to another, and it almost always goes to the places and things that capture our eye.

    The brain fills in the blanks

    But why is it that we don’t even seem to notice these jumps? Because saccades are performed at such a high rate of speed, the images that are shown on the retina of the eye become distorted at the time that they are being performed. Because the brain is unable to make use of this picture in any way, it is simply thrown away. The brain automatically fills in the gap of a few microseconds so that we do not experience temporary blindness. The gap is filled with a picture of the target point rather than the starting point. What we think we are seeing is actually always delayed by a few microseconds.

    This can be proven with another simple experiment: while watching a ticking clock, it is common to see that the initial second appears to last for an exceptionally long amount of time. After that, the hand moves ahead at its usual slow and steady speed. This particular optical illusion is sometimes referred to as “chronostasis,” which literally means “time standing.”

    This happens because the brain is able to make a connection between the moving eyes and the still picture of the clock. This may account for as much as one-tenth of a second of the total time. Now, if you look at the clock precisely when the hand has just moved, you will see the whole second, as well as a tenth, added onto it.