Blog Post

How Your Eyes Work At Night

Harrold Opticians • December 31, 2019

It is widely known that your eyes need light to see. Your sight begins when light enters the eye, the light triggers light-sensitive cells in the back of your eye. This causes signals to be sent from the optic nerve to the brain which is what makes us see.
So, if we need light to see, how can we see in the dark?

Our eyes can let us see things around us in an incredibly wide range of lighting conditions, from incredibly bright to almost pitch black. This is due to different parts of the eye working together to ensure that you can see in different settings.
In dark conditions, three parts of the eye work in unison to allow us to see. These three parts are;

The Pupil - The pupil works by expanding and contracting depending on the lighting conditions. If you are in really bright light, your pupils will shrink down until they are really small in order to block the amount of light that will reach the retina. In the dark, your pupils will expand until they are really wide in order to let more light into the eye.

Rod & Cone Cells - There are two different types of cells in our eyes that are used to see light, these are called rods and cones. The cone cells allow us to see fine detail and colour, however, the cells need bright light in order to able us to do this. The rod cells can only detect black and white and have a much poorer resolution to cone cells. However, they remain extremely sensitive, even in very low light.

Photopigments – Rod and cone cells both contain chemicals called photopigments that are extremely light-sensitive. When the photopigments are exposed to light a chemical reaction happens where the light energy is converted into electrical activity that our brains can interpret. The key photopigment for seeing in the dark is known as the rhodopsin pigment. When light is intense, the rhodopsin pigment decompose which reduces your eyes sensitivity to dim light. In darkness, the pigments regenerate. This process is known as ‘Dark Adaption’, where the eye adjusts to see in low lighting conditions.

These three parts of the eye are what enables us to see in the dark. It should be noted that when you are suddenly exposed to a low lighting situation, your eyes won’t adjust immediately. In fact, our eyes can adapt and adjust to bright lighting conditions much quicker than dark lighting conditions. Cone cells can attain their maximum sensitivity to bright light in 5 minutes, whilst rod cells need up to 45 minutes of darkness before being able to attain 80% dark adaption. Total dark adaption can take several hours.
There are things you can do to help your eyes adapt more quickly to dark lighting conditions;

Wear Sunglasses – Exposure to bright sunlight can reduce your eyes' ability to adjust to dark lighting conditions, sometimes permanently. Wearing red-tinted sunglasses for up to 3o minutes before going into low light will help your eyes adjust to the dark. This is a trick that pilots use before flying at night.

Lower the Brightness on Your Screens – Lowering the brightness on your computer, tv and phone screens means your eyes won’t have to adjust as much when in dark lighting conditions.

Avoid Looking Directly at Bright Lights – Bright light can massively increase the amount of time you need for your eyes to adjust to the dark. Avoid looking directly at bright lights to help your eyes adjust to darkness, particularly at night. When driving at night, try to avoid looking into the headlights of oncoming traffic, this can affect your eyes adjusting to the dark which is dangerous for night-time driving.

If night-time driving is difficult for you, consider trying EnRoute Lenses. EnRoute lenses offer significant reduction of reflections and uncomfortable glare from oncoming traffic. They have a specially designed glare filter and an optional contrast-enhancing filter, allowing better contrast in low light conditions.
To find out more, visit our EnRoute page: http://www.eyewear.harroldopticians.co.uk/c/186099

January 20, 2025
Myopia, often called short-sightedness, is one of the most widespread eye conditions affecting children. By 2050, it’s estimated that 50% of the global population will be affected by this condition, which is why we are passionate about protecting your child’s eye health. In this article, we’ll explore what myopia is, why it’s important to slow its progression, and the innovative management options we offer to support your child’s vision. What does being short-sighted really mean? 
December 23, 2024
As we step into a new year, there's no better time to reimagine your personal style – and what better place to start than with a new pair of glasses? Eyewear does more than help you see clearly: it’s a fashion statement too. It’s a statement of who you are. Glasses are the first thing anyone sees when they look at your eyes. Our range includes three exceptional brands that can transform your 2025 style game. You’ll find our most popular glasses among these premium collections. Face À Face 
November 25, 2024
At Harrold Opticians , we believe styling glasses is a unique affair. Whether you prefer understated elegance or eyewear that makes a statement, our personalised frame styling consultation ensures every patient finds glasses that perfectly suit their face, lifestyle, and personality. With our expert guidance, what can feel like an overwhelming decision becomes a simple and enjoyable experience. How To Choose The Right Glasses - Our Approach 
November 25, 2024
Have you ever thought about how much work your brain and body do just to keep up with the world around you? Every day, your five senses work together, taking in and processing your environment so you can make sense of life and enjoy it fully. Among them, your ears play a crucial role, picking up sounds and vibrations that allow you to chat with loved ones, stay alert to potential dangers, lose yourself in music, or laugh along with a great story. Our ears and our heaving never go to sleep but remain alert, even when we’re not. That’s why it’s so important to look after them. Today, we’re diving into the signs of hearing loss, why regular hearing tests matter, and the services we offer to keep your hearing in optimum shape. Are you experiencing hearing loss?
June 3, 2024
Top 6 Tips for Headphone Users
May 7, 2024
High blood pressure, or hypertension, affects millions of individuals worldwide and is a significant risk factor for various health complications. Among these complications, one lesser-known but critical aspect is its impact on eye health. Here we have connections between high blood pressure and eye disease, focusing on causes, symptoms, diagnostic methods, and treatment approaches for hypertensive retinopathy. High blood pressure occurs when the force of blood against the artery walls is consistently too high. Various factors contribute to hypertension, including excess weight, high salt intake, genetic predisposition, stress, and lifestyle habits like drinking alcohol and smoking. Over time, uncontrolled hypertension can damage blood vessels throughout the body, including those in the eyes. Hypertensive retinopathy, the eye disease associated with high blood pressure, often progresses without noticeable symptoms in its early stages. However, as the condition advances, individuals may experience symptoms such as: Blurred or dim vision Vision loss Double vision Headaches Sudden vision changes, indicating a medical emergency. Examinations: Diagnosing hypertensive retinopathy involves a comprehensive eye examination performed by an eye care professional. Key diagnostic methods include: Ophthalmoscopy: Using an ophthalmoscope, the eye doctor examines the retina to assess the condition of the blood vessels. Narrowing of blood vessels and signs of fluid leakage may indicate retinal damage due to hypertension. Optical Coherence Tomography ( OCT ): This imaging technique provides detailed cross-sectional images of the retina, allowing for the detection of abnormalities such as retinal swelling (edema) or thickening. Fundus Photography: High-resolution images of the retina are captured to document changes in retinal structure and blood vessel appearance over time. Treatments: The primary goal of treating hypertensive retinopathy is to control high blood pressure to prevent further damage to the retina and preserve vision. Treatment strategies may include: Lifestyle Modifications: Adopting a healthy lifestyle can help lower blood pressure and reduce the risk of eye complications. Recommendations include maintaining a balanced diet low in sodium, engaging in regular exercise, managing stress through relaxation techniques, quitting smoking, and limiting alcohol intake. Medication: When lifestyle changes alone are insufficient to control blood pressure, healthcare providers may prescribe antihypertensive medications. These medications work to lower blood pressure levels and reduce the risk of complications associated with hypertension, including hypertensive retinopathy. Regular Monitoring: Individuals with hypertension and hypertensive retinopathy require regular monitoring of their blood pressure and eye health. Routine eye examinations allow for early detection of retinal changes and adjustment of treatment strategies as needed. High blood pressure poses a significant threat to eye health, leading to complications such as hypertensive retinopathy. Understanding the causes, symptoms, diagnostic methods, and treatment options for this condition is crucial for individuals with hypertension.  By effectively managing blood pressure and seeking timely eye care, individuals can reduce the risk of vision loss and preserve ocular health in the presence of hypertension. Book your eye test with Harrolds Opticians today for a full eye health check. Regular communication with healthcare providers and adherence to treatment recommendations play pivotal roles in safeguarding both overall health and vision.
May 1, 2024
While you’re reading this on your screen, did you know, the onset of computer eye strain is becoming increasingly common? It is imperative to shed light on the symptoms of this modern affliction and explore the advantages of Visual Display Unit (VDU) glasses in alleviating its effects. Symptoms of Computer Eye Strain: 1. Eye Fatigue: Prolonged screen use can lead to eye fatigue, causing a sensation of tiredness or heaviness in the eyes. 2. Headaches: Persistent headaches, often centred around the forehead and temples, are a prevalent symptom of computer eye strain. 3. Dry Eyes: Reduced blinking during screen time can result in dry eyes, characterised by a gritty feeling, itching, and redness. 4. Blurred Vision: Extended screen exposure may cause temporary blurred vision, requiring frequent squinting or rubbing of the eyes. 5. Neck and Shoulder Pain: Poor posture during digital device use can contribute to neck and shoulder pain, adding to overall discomfort. 6. Light Sensitivity: Some individuals may experience increased sensitivity to light, further intensifying their discomfort. 7. Difficulty Concentrating: Visual discomfort can extend to cognitive challenges, leading to difficulty concentrating on tasks and decreased productivity. Seeing Clearly in the Digital World: A Guide to VDU Glasses In our fast-paced, digital-centric lives, our eyes are working overtime, often leading to discomfort and strain. Here is a topic that can make a significant difference in your visual comfort – Visual Display Unit (VDU) glasses. Understand what VDU glasses are and how they can be your trusted companions in your digital lifestyle. Understanding VDU Glasses: Visual Display Unit (VDU) glasses, also known as computer glasses or digital screen glasses, are specially designed eyewear crafted to address the unique visual challenges posed by prolonged screen use. These glasses are not just a fashion statement; they're a tailored solution to enhance your visual comfort in the era of digital dominance. Benefits of VDU Glasses: Blue Light Protection: One of the key features of VDU glasses is their ability to filter out a sizeable portion of the harmful blue light emitted by digital screens. Exposure to excessive blue light can contribute to eye strain, fatigue, and disrupt your sleep patterns. VDU glasses act as a shield, reducing the impact of blue light on your eyes. Reduced Glare: Anti-reflective coatings on VDU glasses help minimise glare from screens. Whether you're working on a computer, gaming, or binge-watching your favourite show, reduced glare means clearer vision and less strain on your eyes. Optimised Contrast: VDU glasses enhance contrast, making it easier for your eyes to distinguish between characters and images on the screen. This feature contributes to improved visual clarity, reducing the effort your eyes need to focus. Preservation of Visual Health: By mitigating the negative effects of extended screen time, VDU glasses play a crucial role in maintaining overall visual health. They can be particularly beneficial for those who spend a significant portion of their day in front of digital devices. Enhanced Comfort: VDU glasses are designed with your comfort in mind. They reduce eye strain, alleviate discomfort, and provide a more relaxed viewing experience. Whether you're working, studying, or enjoying leisure activities on your devices, VDU glasses are there to support you. Choosing the Right Pair: When selecting VDU glasses, it's essential to consult with your optician to ensure a proper fit and prescription, if needed. The right pair of VDU glasses should complement your lifestyle and address your unique visual needs in the digital realm.  Screens have become an integral part of our daily lives so investing in Visual Display Unit glasses is an investment in your visual well-being. These purpose-built glasses are not just about seeing clearly; they're about seeing comfortably in the digital age. So, why not make your digital experience a more comfortable one? Consider VDU glasses and treat your eyes with the care they deserve in this digital era.
February 27, 2024
The Importance of Regular Eye Tests
January 29, 2024
At Harrold's Opticians we understand the importance of clear vision and your unique eyewear needs. If you've ever found yourself asking, "Do I need two pairs of glasses?" – you're not alone. Let's explore the benefits of having two pairs of glasses and why it might just be a significant change for your eye health and lifestyle. 
January 3, 2024
The Importance of Regular Eye Check-ups
Show More
Share by: