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标签： 眼睛健康

发表于 通过 Dr. Sherman Tung

20/20 Vision

When having an eye exam done you might have been told that you have 20/20 vision, but what exactly does that mean? To put it simply, having 20/20 vision indicates that at a distance of 20 feet, you are able to see the smallest letters that should be seen at 20 feet. If you have 20/40 vision, it indicates that you need to be at 20 feet to see what a person with 20/20 vision can see at 40 feet. On the other hand, if you have 20/15 vision, you can see at 20 feet what a person with 20/20 vision can see at 15 feet.

How do we measure our visual acuity?

There are many ways to measure a patient’s visual acuity, but the most common way is through using a Snellen chart that presents with numerous lines of letters above one another. Letters found at the top of the chart are larger and easier to see but become smaller and difficult to read as you move down the chart. Patients are tested by covering one eye and reading the letters from top to bottom at which point they repeat these steps while covering the other eye. Afterwards, patients will use both eyes together to determine the lowest line they are able to read clearly.

发表于 通过 Dr. Sherman Tung

How do my eyes adjust to different lighting?

拍摄者 Agence Olloweb 在 不飞溅

Our eyes are incredible at adapting to different lighting conditions. This is done through the iris and pupil of the eye. Our pupils are the dark hole at the front of the eye which allows light to enter and form an image on the back portion of our eye. This pupil size is controlled by muscles found on the iris, which is the coloured portion surrounding the pupil. In bright sunlight, our pupils will begin to constrict, allowing less light to enter into the eye. On the other hand, when we are in a dark room our pupils will become bigger and increase the amount of light getting into the eye.

credit: https://www.sciencelearn.org.nz/resources/50-how-the-eye-focuses-light

Once the light enters through our pupil, it hits the back of our eye called the retina. The retina has two types of photoreceptors called rods and cones. Rods are responsible for night time vision and cones are responsible for day time vision. When we are in a dark room, rods are the ones that let us see.

Dark adaptation

The reason you are momentarily blind in the dark when going from a well-lit room is because it takes some time for our eyes to adjust. This is referred to as dark adaptation. During this period, the rod receptors are the key players to fully adapt and return vision to normal.

发表于 通过 Dr. Sherman Tung

网上买眼镜可以吗？我真的需要去看验光师/配镜师吗？

拍摄者 武艺 在 不飞溅

在考虑是否在线购买眼镜时，乍一看似乎更方便，价格也可能更低。但是，验光师给你的处方只是决定眼镜能否有效改善视力的众多因素之一。让我们来看看它的优缺点：

网上购物的优点：

  • 款式和颜色选择更丰富
  • 不同网站之间有很多选择
  • 通常可以节省成本（稍后会详细介绍）。

网上购物的缺点：

  • 这样你就错过了让训练有素的专业人士帮助你确保眼镜佩戴合适的机会。
    就舒适性和有效性而言
  • 为了维持你在网上看到的低价，镜框的质量控制往往会被牺牲。
  • 具体的测量包括瞳距 (PD)、寻找最佳光学中心以及其他测量。
    进步人士要么经常出错，要么无法在线购买。
  • 与实体店相比，网上订购药品时出现处方问题的情况总体上要常见得多。
    亲自

最初看似省时省钱的方法，如果出现上述任何问题，从长远来看最终可能会让双方都付出更多代价。此外，不合适的眼镜还可能导致以下常见问题：头痛、疲劳、恶心/眩晕、眼睛疲劳、眼镜容易从鼻梁上滑落，以及鼻子/耳朵周围出现疼痛/压痕。高度近视、儿童、复杂处方以及多焦点处方的人士尤其应该考虑到实体店验配，而不是在线验配。.

发表于 通过 Dr. Sherman Tung

What reading under the covers does to your eyes

Image by Freepik

While it is untrue that reading in the dark will permanently damage your eyes it can cause shorter term issues. You may have to strain harder which can lead to headaches, irritated eyes, general eye fatigue. If this is coupled with other existing issues you may also experience blurry vision or even double vision temporarily. The extra strain and need to focus may also prevent you from blinking as often, leading to dry eye symptoms.

发表于 通过 Dr. Elisa Xiao

Will I Develop Presbyopia?

拍摄者 bruce mars 在 不飞溅

Presbyopia is the gradual loss of your eyes’ ability to focus up close. This tends to start around your early 40s and progresses until around the age of 65. You may notice starting to hold reading material further away to keep it clear, blurry vision at previously normal reading distance, eyestrain or headaches after extended periods of reading.

Managing presbyopia

Depending on your health, lifestyle and preferences, your eye care specialist may suggest any of the following methods to correct presbyopia:

  • Eyeglasses in the form of readers, bifocals, progressives, etc.
  • Contact lenses, typically multifocal or monovision
  • Surgeries
  • Eye drops such as Vuity

Can I prevent presbyopia?

You can’t prevent presbyopia since it’s a part of the natural aging process. You can, however, take steps to protect your eye health. This includes:

  • Wearing sunglasses to shield your eyes from harmful ultraviolet (UV) rays.
  • Eat foods rich in nutrients that promote eye health, including vitamin A, vitamin C, vitamin E and lutein, and Omega-3s
  • Improve lighting in work areas
  • Increase font and change contrast in smart phones or computer devices etc.
发表于 通过 Dr. Sherman Tung

Can I Wear my Contact Lenses for Longer than I’m Suppose to?

拍摄者 Lensabl 在 不飞溅

If I’m careful with cleaning, can I wear my dailies for more than 1 day?

Daily disposables are thinner and are made of a material that is not made to resist bacteria and buildup. So, if you try to clean or disinfect these thin lenses you may actually create breaks instead, further increasing infection risk. Using a compatible brand of soft contact lens rewetting drops to hydrate your daily disposables for comfort is acceptable.

What happens if I wear dailies for more than 1 day?

Wearing daily disposable contact lenses more than once puts you at risk for discomfort, dryness, corneal ulceration/scarring, and eye infections.

Differences between Dailies, Bi-weeklies, and Monthlies

Dailies are worn only for one day and discarded when you remove them, these are typically very thin and have a high water content. Natural deposits from your eyes build up easily on their surface, and they cannot be reused. This could mean more convenience but also, depending on how often you replace them, more costly.

Monthly or bi-weekly contact lenses are thicker than daily disposables. The thicker composition makes them more durable and long-lasting, and they are usually more resistant to drying out. However, they must be disinfected regularly in order to ensure healthy wearing.

发表于 通过 Dr. Elisa Xiao

验光师、配镜师和眼科医生是同一类人吗？

图像来自 macrovector 在 Freepik 上

作为患者，了解这三家眼科诊所各自的角色和服务至关重要。
专业人士会帮助您获得所需的特定眼科护理，知道该问哪些问题，并与您合作。
与您的医疗保健提供者一起确定适合您的合适解决方案。.

验光师

验光师会进行眼科检查，以评估您的眼睛整体健康状况，并为您开具隐形眼镜、眼镜或低视力辅助设备的处方。验光师会进行多项检查，包括视力（您远近视力如何）、辨色能力、深度知觉、视网膜健康状况、眼压等等。验光师可能会使用散瞳眼药水，以帮助检测青光眼、白内障、黄斑变性等眼部疾病。.

眼科医生

眼科医生是专门从事眼部健康及相关疾病的医学博士。眼科医生需接受研究生培训，才能具备治疗眼部疾病的资质，包括药物治疗和手术治疗。眼科医生为常见的眼部问题（例如白内障）提供手术解决方案，并监测青光眼等眼部疾病，同时还能进行激光矫正手术。.

眼镜店

验光师负责验配、调整和配发处方眼镜和非处方眼镜。他们不进行眼科检查，也不开处方，但可以协助您配镜、调整眼镜以及订购新的/更换的隐形眼镜。.

发表于 通过 Dr. Melody Tong

Are You Ready For Your Eye Exam?

拍摄者 nrd 在 不飞溅

Having an annual eye exam is a great way to not only take care of your eyes but your overall health as well. Eye exams can detect early signs of conditions such as diabetes and high blood pressure. Here are some tips to help you make the most of your next visit!

What to think about:

  • Have I noticed any eye problems such as blurry vision, flashes of light, floaters, redness, or double vision?
  • Are my daily activities being affected by my vision?
  • How do I take care of my contact lenses or glasses
  • Have I had any surgeries or injuries in my eyes that I could let the doctor know about?
  • Any family history of eye conditions such as glaucoma?

What to bring:

  • Your current glasses or contact lenses even if you have multiple pairs for different tasks
  • A list of your medications/supplements you are taking
  • Have someone who can drive you home or a method of transportation ready for if you have your eyes dilated. This happens often in yearly eye exams and can make you sensitive to light and have blurry near vision (~4-6 hours)
  • Vision and health insurance information

Questions to ask:

  • Differences between contacts and glasses for you and how this compares to surgery options as well?
  • If anything has changed in my ocular health since the last visit?
  • What any symptoms you may have mean and what you can do to prevent them from getting worse or resolve?
  • When should I return for my next visit?

发表于 通过 Dr. Elisa Xiao

Are Cosmetic (Color) Contact Lenses Safe?

photo credit: drtavel.com

Cosmetic contact lenses or colored contact lenses may seem harmless but can lead to severe eye problems or loss of vision if not fit by an eye specialist. You need to have a prescription for contact lenses as they are deemed medical devices by the U.S. Food and Drug Administration (FDA). Non- prescription contacts can create problems due to issues such as poor fitting or unclean packing/creation.

When contact lenses not specifically fitted and sized for your eyes are worn, the cornea may be scratched, potentially leading to the following:

  • Painful corneal abrasion
  • Decreased vision
  • Redness, soreness, itching
  • 对光敏感
  • Allergic reactions
  • Corneal ulcers

Eye infections are also very common in non-prescribed contact lenses and may lead to the following:

  • Persistent eye pain
  • Decreased vision
  • 对光敏感
  • Discharge from the eye (this could be green/yellowish mucus like or more watery)

Discussing your options and proper contact lenses hygiene with an eye care professional, having the
proper measurements of your eyes taken, and getting a valid prescription is an easy way to avoid these
potentially life changing complications.

发表于 通过 Dr. Elisa Xiao

Is it Blepharitis?

Blepharitis is when you have inflammation of your eyelids. Sometimes the cause is from skin conditions
such as dandruff or rosacea while other times the cause could be from overpopulation of bacteria or
even parasitic mites called demodex.

Image from: https://www.allaboutvision.com

Some signs or symptoms you may be experiencing include:

  • Red, swollen eyes
  • A gritty or burning sensation in your eyes
  • Excessive tearing or itching
  • Dry eyes or crusted eyelashes
  • Increased sensitivity to light
  • Dandruff-like scales on the eyelashes
  • Blocked eyelid glands
  • Eyelashes may fall out of be misdirected inwards causing damage to the cornea
  • Increased risk of infection

So what can you do?

With so many varying signs and possible causes it is important to have a comprehensive eye exam in
order to determine the type of blepharitis you may have. Once determined a specified treatment plan
can be made to manage the condition. Luckily, in many cases taking care of your eyelid hygiene,
whether in office or at home, is a simple enough method in keeping the symptoms of blepharitis at bay
and from affecting your daily life. It is important to remember that this will likely be a long term plan.
Treatments in office or at home may help jump start your recovery, but proper hygiene must be
maintained overtime, or the symptoms of blepharitis may return.

At-home ocular hygiene tips:

  • Frequently wash your the scalp and face
  • Warm compresses to help soften crust and help unclog oil glands present in eyelids
  • Use artificial tears (often helpful when placed in the fridge to bring down inflammation)
  • Limit or stop using eye makeup during treatment, as it makes lid hygiene more difficult.
  • Nutrition changes/supplements such as omega-3s

More severe cases may warrant in-office treatments:

Photo credit: Eye Health Shop, 2023

  • Intense Pulsed Light therapy, involving the application of bright red light pulses to your eyelids
  • BlephEx®, which involves cleaning your eyelid margins with microblepharoexfoliation.
  • Lipiflow or other dry eye focused treatments may be used concurrently
  • Depending on your case antibiotics or steroids or tea tree oil products may be prescribed
  • Products may be available in office to complement treatment, such as BIHOCL or eyelid scrubs