What Is Blue Light? How Does It Impact Sleep?

Updated Dec 14, 2024 | 10:45 PM IST

SummaryScreens of electronic devices such as smartphones, computers, tablets, and televisions emit blue light. But does it impact your natural sleep cycle and circadian rhythm?
Blue Light

Blue Light (Credit: Canva)

Blue light emitted by devices like smartphones, computers, and televisions is becoming a major factor disrupting our sleep cycles. Research reveals that a significant number of Americans use electronic devices close to bedtime, contributing to poor sleep quality. Reducing exposure to blue light, particularly in the evening, is a simple yet effective way to help your body prepare for restful sleep.

What Is Blue Light?

Blue light is part of the visible light spectrum and is emitted by natural and artificial sources like the sun, fluorescent lights, LED lights, and digital screens. This wavelength is known for influencing our alertness, mood, and sleep patterns. During the day, blue light plays a role in regulating circadian rhythms, helping us stay alert and focused. However, exposure to it in the evening can have a detrimental effect on sleep quality.

How Does Blue Light Impact Circadian Rhythms?

Circadian rhythms are 24-hour cycles that control essential bodily functions, including sleep. Light is the primary factor that aligns these rhythms with day and night. Historically, exposure to sunlight during the day helped set our body clocks, signaling when to be awake and when to sleep. However, the widespread use of artificial lighting and electronic devices has introduced more light exposure after dark, disrupting these natural cycles.

Blue light, in particular, has the strongest impact on circadian rhythms. During daylight hours, blue light helps us feel alert by stimulating the brain, raising body temperature, and increasing heart rate. But in the evening, exposure to blue light can confuse the body’s internal clock, suppressing melatonin—the hormone responsible for making us feel sleepy. As a result, our brains may remain in “daytime mode,” preventing us from winding down for the night.

Health Consequences Of Disrupted Sleep

Persistent disruption of circadian rhythms can lead to a range of health issues, including metabolic disorders, poor mental health, and increased risk for conditions like depression and anxiety. Furthermore, the inability to sleep well at night affects cognitive performance, mood, and overall well-being. Chronic exposure to blue light in the evening may significantly contribute to these negative health outcomes.

Devices That Emit Blue Light

Many common devices in our daily lives emit blue light, including:

- Smartphones and tablets

- Computer monitors and laptops

- Televisions and e-readers

- LED and fluorescent lighting

- Video game consoles

How To Minimize Blue Light Exposure

To reduce the effects of blue light on your sleep, here are some practical strategies:

1. Turn off screens before bed: Try to avoid using electronic devices at least two to three hours before bedtime. Reducing screen time helps prevent blue light from interfering with melatonin production.

2. Adjust your lighting: Dim your home’s lights or switch to warmer-toned lighting in the evening. You can also use lamps with red or orange light, which are less likely to impact your circadian rhythms.

3. Night mode settings: Many smartphones and computers have a "night mode" feature that reduces blue light emission. Make use of these features to limit exposure in the hours leading up to bedtime.

4. Blue light-blocking glasses: Special glasses designed to filter out blue light may be helpful for some individuals. These glasses can block or reduce the melatonin-suppressing effects of blue light.

5. Apps for blue light reduction: There are several smartphone and computer apps available that reduce blue light emission, allowing you to use your devices before bed without disturbing your sleep.

6. Create a sleep-friendly environment: If you can’t control light sources in your bedroom, consider using an eye mask to block out ambient light and promote better sleep.

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Sleep Apnoea in People Who Aren’t Obese: Why Weight Alone Shouldn’t Decide Who Gets Tested

Updated Oct 17, 2026 | 03:00 PM IST

SummarySleep apnoea can affect people who aren’t obese due to factors such as airway anatomy, age and genetics. Recognising symptoms and seeking timely testing can help prevent complications.
Sleep Apnoea in People Who Aren’t Obese: Why Weight Alone Shouldn’t Decide Who Gets Tested

Credit: iStock

Obesity is often associated with obstructive sleep apnea or OSA. Extra body fat is a key risk factor. Still, it is a mistake to think OSA only happens when someone is heavy. Many people who have a normal weight may not connect their symptoms to a sleep issue.

They can go for years without a proper diagnosis. Research also makes it clear that OSA can show up in people who are not obese. Risk may be more than weight-dependent and include factors such as upper airway anatomy, age, sex, family history, and others.

How Airway Anatomy Can Increase The Risk

Weight is only part of the story. The jaw, the palate, the tongue, and the passages in the upper throat can affect what happens during sleep. The airway can narrow or collapse more easily for some people. A person may not be big in body size but can have a tight or smaller upper airway.

They might have a jaw that drops back. Other facial and skull features can also increase the likelihood of OSA. Your nose problems, smoking, drinking and other unwholesome activities on Sunday could also be factors.

Also read: ‘Feels Like I’m A Few Days From Death’: Olympic Sprinter Beth Dobbin Says She Is Bedbound 22 Hours A Day

Why Age And Menopause Matter

Age matters too. With time, muscle tone can change. The way the airway works can also shift. As a result, the upper airway may be more likely to collapse during sleep. For women, the risk may also shift around menopause and after it. This is why OSA should not be treated as a problem that only affects overweight men.

The symptoms should be taken seriously, not the scale. Signs such as loud snoring or snoring often, pauses seen in breathing, waking up suddenly and feeling short of breath, or choking during sleep can all call for assessment. Morning headaches can occur as well. Day-to-day problems like poor focus, irritability, and being very sleepy in the daytime are common clues. Some people do not report classic sleepiness. They may mainly notice restless sleep or ongoing tiredness during the day without a clear reason

How Doctors Assess Sleep Apnoea

A clinician should look at more than BMI. They can start with symptoms, a sleep history, neck size, what the upper airways look like, and any related health issues. If obstructive sleep apnoea is a real concern, a sleep test can show whether breathing problems happen during sleep.

The main point is this: a person can be slim and still have sleep apnoea. Deciding on testing should follow the full clinical picture, not body weight by itself. When this is remembered, some people may get help sooner, instead of having their tiredness written off as stress, bad sleep, or just normal fatigue.

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Beyond Traditional Cancer Surgery: How Newer Techniques Are Making Complex Operations Safer

Updated Oct 17, 2026 | 01:00 PM IST

SummaryAdvances in robotic-assisted surgery and minimally invasive techniques are helping surgeons tackle complex cancers with greater precision, potentially reducing tissue damage, complications and recovery time while improving patient outcomes.
Beyond Traditional Cancer Surgery: How Newer Techniques Are Making Complex Operations Safer

Credit: iStock

A patient suffering from a rare tumour involving the sciatic nerve has made a good recovery following a successful robotic-assisted sciatic nerve schwannoma resection, marking an important milestone in advanced, minimally invasive surgical care.

Sciatic nerve schwannomas are uncommon, benign tumours that develop from the cells surrounding a nerve. Because the sciatic nerve is responsible for important motor and sensory functions of the lower limb, surgery in this region can be technically challenging. The key objective is to remove the tumour while preserving the functioning nerve fibres and minimizing the risk of neurological complications.

How Robotic Technology Can Aid Complex Surgery

The patient underwent robotic-assisted surgery under the care of a multidisciplinary surgical team. The use of robotic technology provided enhanced visualization and precise control of surgical instruments, allowing meticulous dissection around the affected nerve.

For the patient, the successful procedure meant not only removal of the tumour but also the prospect of returning to normal daily activities with preservation of neurological function.

Whenever the doctor operates on a tumour involving an important nerve, their priority is to achieve complete and safe tumour removal while protecting the nerve and its function. Robotic assistance can offer greater precision and visualization in carefully selected cases.

Following the procedure, the patient was closely monitored for neurological recovery and postoperative complications. The patient is doing well and recovering satisfactorily, providing an encouraging outcome following this complex surgical intervention.

How Minimally Invasive Techniques May Benefit Patients

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The case demonstrates how advances in surgical technology can translate into meaningful benefits for patients. Robotic-assisted surgery, when used in appropriately selected cases, can support surgeons in performing delicate procedures with enhanced precision while potentially reducing tissue trauma and facilitating recovery.

For patients diagnosed with nerve tumours, early evaluation and appropriate treatment planning are important. Symptoms can vary depending on the location and size of the tumour and may include pain, tingling, numbness, or weakness in the affected limb. Detailed imaging and neurological assessment help specialists determine the most appropriate treatment strategy.

The successful outcome reflects the importance of combining experienced surgical expertise, advanced technology, and patient-centred care. For this patient, the journey from diagnosis to successful tumour removal and recovery offers an encouraging example of what modern surgical care can achieve.

By Dr. S.K. Bala, Consultant Department of Surgical Oncology & Advanced Robotic Surgery, CMRI, CK Birla Hospitals, Kolkata

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Rare Canine Tooth Found In Indian Teen’s Eyelid: What Is An Ectopic Tooth?

Updated Oct 17, 2026 | 12:11 AM IST

SummaryEctopic teeth have been documented in several locations, including the nasal cavity, chin and maxillary sinus, an air-filled cavity within the cheekbone. Previous reports have also described teeth in the lower part of the eye socket. However, this is the first reported case of an ectopic tooth in the superior orbit, the upper region of the eye socket.
Rare Canine Tooth Found In Indian Teen’s Eyelid: What Is An Ectopic Tooth?

Credit: Opthalmology Journal

Doctors in India’s southern state of Tamil Nadu surgically removed a fully developed canine tooth from the upper eyelid region of a 16-year-old boy. They described the case as the first reported instance of an ectopic tooth in the upper part of the eye socket.

The case was reported by specialists at Aravind Eye Hospital in Madurai in the journal Ophthalmology.

What Did The Doctors Find?

The teenager visited the hospital with painless swelling of his left upper eyelid that had lasted a month. He had no history of injury to the area.

During the examination, doctors noticed two firm, whitish projections beneath the swollen area near the inner side of the upper eyelid, the experts shared in the paper.

A computed tomography (CT) scan revealed a dense structure resembling a tooth, with a crown and root, originating from the roof of the left eye socket. It extended towards the tissues in front of the orbital septum, a thin barrier separating the eyelid from the deeper eye socket, and protruded outwards with two tooth-like points on its surface.

The projections' appearance and texture raised the possibility that they were teeth. Dr. Meghana Tanwar, a medical consultant at Aravind Eye Hospital, told Live Science that they had a “fairly smooth surface and were hard on palpation.”

The doctors surgically removed the structure. Examination confirmed that it was a mature canine tooth without teratomatous elements, consistent with an ectopic tooth in the upper part of the eye socket.

Also read: Hours Of Sitting, Gaming And Binge-Watching OTT? Doctors Warn Of Blood Clot Risk In Young People

What Is An Ectopic Tooth?

An ectopic tooth develops or emerges in an abnormal location. Some remain within the mouth but appear outside their usual positions in the dental arch, while others develop outside the normal arrangement of teeth.

The latter is particularly unusual. In this teenager's case, the tooth was located in the upper orbital region rather than within the normal dental arch.

Before confirming the diagnosis, doctors considered whether the projections could be associated with a teratoma, a type of tumor that can contain different tissues, including bone and tooth tissue. They also considered whether a foreign object might be lodged in the eyelid.

Imaging and examination of the removed structure helped establish that it was a mature tooth rather than tissue associated with a teratoma.

Why Is This Case Unusual?

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Ectopic teeth have been documented in several locations, including the nasal cavity, chin and maxillary sinus, an air-filled cavity within the cheekbone. Previous reports have also described teeth in the lower part of the eye socket.

However, the doctors said they could not find an earlier report of an ectopic tooth in the superior orbit, the upper region of the eye socket.

“To the best of our knowledge this is the first and only ectopic tooth reported in the superior orbit,” Tanwar told Live Science.

“This was a first not just for us but the world over,” she said of the case. “We were very surprised by it.”

What Causes Ectopic Teeth?

READ: Non-Healing Mouth Sores? This Silent Symptom Could Signal Oral Cancer, Warn Doctors

The doctors could not determine why the tooth developed in this unusual location.

Possible explanations for ectopic tooth development include abnormalities during development, genetic factors, infections and physical trauma. However, the cause in this case remains unknown.

Imaging did not reveal any additional ectopic teeth. Tanwar said the likelihood of the teenager developing another such tooth was low.

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