Does temperature affect contact lenses?

If you wear contact lenses, you might worry about what happens when they're left outside on extremely hot or cold days. Luckily, a recent study found that as long as the packaging isn't damaged, your contact lenses and their solutions stay safe to use, even in extreme temperatures.

Winter brings icy winds, indoor heating and dry eyes. Contact lenses can still be worn during winter. You may find that wearing contact lenses for dry eyes can boost your comfort. But what about vision quality and eye health in different conditions? Our tips will help you keep vision sharp and eyes feeling healthy, whether you’re working long hours, hitting the ski slopes, or meeting friends for coffee. In winter, your glasses instantly fog up when you come in from the cold. That doesn’t happen with contact lenses.

Tips for wearing contact lenses this winter:

1. Wear sunglasses and contact lenses with UV blocking in the snow, the sun’s rays are strong in winter

2. Keep eyes hydrated - the wind and cold air can cause dry eyes

3. You can wear contact lenses in freezing temperatures

4. If you feel ill, take extra precaution with hand washing before and after handling lenses

For contact lens wearers, there is a high risk of developing dry eyes syndrome due to several factors, such as:

• 1. Contact lenses can disrupt the natural tear film and interfere with the regular distribution of tears across the eye’s surface. This results in an increased rate of tear evaporation, exacerbating dry eye symptoms.
• 2. Contact lenses can act as a barrier that limits the oxygen supply to the front surface of the eye. This reduction in oxygen can cause the eyes to become dry and irritated.
• 3. The materials used in contact lenses can also be a factor in developing dry eyes. Some lenses may have a higher tendency to attract and retain deposits from the tear film or the surrounding environment, leading to increased friction and discomfort.
• 4. Improper contact lens hygiene or wearing lenses for extended periods without breaks can further contribute to dryness. Failure to clean the lenses properly or using inadequate lens care solutions can result in a buildup of debris and bacteria on the lens surface, which can irritate the eyes and disrupt the tear film.

Reference:

• clspectrum.com/issues/2019/february/contact-lens-case-reports
• visionexpress.com/contact-lenses/contact-lens-tips/during-winter
• satopharm.com.sg/tips-for-managing-dry-eyes-due-to-contact-lenses

Inserting and removing your lenses is a snap. After only a few tries, you'll be a pro.

Here are a few tips to help you out.

• Always wash your hands with a mild soap and dry with a lint-free towel before handling your lenses.
• Clean, rinse and disinfect your lenses each time you remove them.
• Always handle the same lens first to avoid mixing up the right and left lenses.
• Remember to handle your lenses gently. eResearch by Navid Ajamin -- summer 2013

Inserting the Lens into your eye

• Put one of the lenses on the tip of the index finger of the hand you write with. Be sure the lens is right-side-out (the edges should turn up, not out).
• Look straight ahead. Pull down your lower eyelid with the middle finger of the same hand.
• Pull the top lid up with the index finger of the other hand and look up.
• Gently place the lens on the lower white of the eye.
• Remove your index finger and release your eyelid.
• Look down, and close your eyes for a moment. The lens will center itself.
• Repeat for the other lens.

Removing the lens from your eye

• Look up and pull the lower lid down with the middle finger of the hand you write with.
• Place your index finger on the lower edge of your lens, and slide the lens down to the white of your eye.
• Squeeze the lens lightly between your index finger and thumb and remove gently.
• Repeat for the other eye.
• If the edges of your lens stick together, place a few drops of saline or multi-purpose solution on the lens and rub gently until the edges separate.

These tips will help guide you, but always follow the advice of your eye care practitioner.

Reference: bausch.com/en/Reference/Inserting-removing-contact-lenses

See Also:

• Ensuring Safe Use of Contact Lens Solution

• Wearing and Caring for Contact Lenses

Video:

• How to Apply and Remove Your Contact Lenses: Step by Step

• Putting contacts on and taking them off

Because of the existence of too much brands and types of soft contact lenses that are available in the market, choosing them can be a bit difficult and confusing task. To escape from this confusion, you can consult an eye care professional or you can follow the guide below. In doing so you can have the best contact lens that fits you and your lifestyle as well. Here are tips on how to select soft contact lenses with much ease.

1. Consider your eye’s sensitivity.

In deciding whether you want to wear daily, weekly or monthly disposables, consider how sensitive your eyes are and how much you are willing to spend on soft contacts. Users with sensitive eyes usually prefer daily or weekly lenses which are more expensive than monthly disposable contact lenses. eResearch by Navid Ajamin -- spring 2013

2. Choose the right color that suits you. Choose between clear contacts or colored contacts.Colored contacts can change or enhance your natural eye color.

3. Choose between traditional or other forms of soft contacts.

Your eye care professional can help you decide if traditional soft contacts or soft contacts for astigmatism are best for you. The severity of your astigmatism will decide whether you can wear traditional soft contacts with minimal impact on your vision.

. Choose bifocal contacts if necessary.

If you have difficulty in focusing on objects that are close up or you have presbyopia, choose bifocal contacts. These are the latest types of contact lenses sold in the market and is a good alternative to bifocal glasses.

5. Know your brand options.

You can review your options so that you can select the best brand of contact for you. You can ask help from your eye care professional. They will give you contact lenses to try on for a period ranging from a day, week or month depending on the lens selected. A schedule of follow up exam is set so that your eye care doctor can examine the fit of the lens and check the health of your eye.

6. Relate your experiences regarding wearing of contact lenses.

Tell the truth about what you experience using the contact lenses during the follow up exam. Tell your doctor whether you like the new lenses or not, or if you need to try a different pair for another trial period. Do not wear lenses that do not fit properly or make you uncomfortable.

7. Choose according to time you can devote for cleaning.

If you are busy and have no time of cleaning your contact lenses, better choose contact lens with a shorter wear period. They may be more expensive but they are better than wearing inadequately cleaned lenses that can damage the health of your eye.

8. Consider other essentials when making a choice.

Have a yearly eye exam for contact lenses even your prescription has not changed. It is necessary to check the health of your eyes regularly. Once your contact lens will rip or tear, throw it at once because it can damage a healthy eye and can cause scarring to your retina. After you have passed the evaluation conducted by your eye care professional you’re able to find the brand that fits you. From here, then you can purchase a supply of your new soft contact lenses.

Reference: contactlenscare.org

What to expect during a contact lens fitting

The first step in a contact lens fitting is a consideration of your lifestyle and your preferences regarding contact lenses, such as whether you might want to change your eye color with color contact lenses or if you're interested in options such as daily disposables or overnight wear. Although most people choose soft contact lenses, the advantages and disadvantages of rigid gas permeable (GP) lenses will likely be discussed as well.

If you are over age 40 and need bifocals, your eye doctor or contact lens specialist will discuss ways to deal with this need, including multifocal contact lenses and monovision (a prescribing technique where one contact lens corrects your distance vision and the other lens corrects your near vision).
Contact lens measurements
Just as one shoe size doesn't fit all feet, one contact lens size doesn't fit all eyes. If the curvature of a contact lens is too flat or too steep for your eye's shape, you may experience discomfort or even damage to your eye. Measurements that will be taken to determine the best contact lens size and design for your eyes include:

Corneal curvature: An instrument called a keratometer is used to measure the curvature of your eye's clear front surface (cornea). This measurement helps your doctor select the best curve and diameter for your contact lenses.
If your eye's surface is found to be somewhat irregular because of astigmatism, you may require a special lens design of lens known as a "toric" contact lens. At one time, only gas permeable contact lenses could correct for astigmatism. But there are now many brands of soft toric lenses, which are available in disposable, multifocal, extended wear and colored versions.

In some cases, a detailed mapping of the surface of your cornea (called corneal topography) may be done. Corneal topography provides extremely precise details about surface characteristics of the cornea and creates a surface "map" of your eye, with different contours represented by varying colors.

Pupil and iris size: The size of your pupil and iris (the colored part of your eye) can play an important role in determining the best contact lens design, especially if you are interested in GP contact lenses. These measurements may be taken with a lighted instrument called a biomicroscope (also called a slit lamp) or simply with a hand-held ruler or template card.

Tear film evaluation: To be successful wearing contact lenses, you must have an adequate tear film to keep the lenses and your cornea sufficiently moist and hydrated. This test may be performed with a liquid dye placed on your eye so your tears can be seen with a slit lamp, or with a small paper strip placed under your lower lid to see how well your tears moisten the paper. If you have dry eyes, contact lenses may not be right for you. Also, the amount of tears you produce may determine which contact lens material will work best for you.

Reference:

goeyecare.net/eye-care-services/contact-lens-fitting-and-evaluations

See Also:

• The ABCs of Fitting Soft Contact Lenses -- optometrysmeeting.org
• How to Determine the Base Curve of a Contact Lens -- healthfully.com

1. قبل از زدن لنز تماسي دستهايتان را كاملا بشوييد.
2. قبل از برداشتن لنز دستهايتان را كاملا شسته باشید.
3. انتخاب صحيح محلول نگهداري كننده گله مندی از لنز را كاهش خواهد داد.
4. تميز كردن لنز باعث ضد عفوني شدن آن نمي شود و بالعكس. بنابراين علاوه بر تميز كردن لنز بايد آنها را هر چند وقت يك بار با محلول هايي مثل پروكسيد هيدروژن ضد عفوني نمود.
5. محلولهاي نگهداري لنز نرم با محلول هاي نگهداري لنز سخت متفاوتند بنابراين آنها را به جاي يكديگر استفاده نكنيد.
6. نوع محلول نگهداري لنز را بدون مشورت با متخصص عوض نكنيد.
7. لنز را در آب يا شامپو نگهداري نكنيد.
8. هرگز از بزاق دهان براي مرطوب كردن لنز ها استفاده نكنيد.
9. بعد از اينكه محلول نگهداري را داخل جا لنزي ريختيد فورا در محلول نگهداري را ببنديد زيرا محلول به وسيله ميكروارگانيسم هاي موجود در فضاي آزاد آلوده خواهد شد.
10. به تاريخ انقضاء محلول هاي نگهداري كننده و سرم فيزيولوژي و خود لنز توجه كنيد.
11. اگر چشمهايتان قرمز و پر خون هستند از زدن لنز پرهيز نماييد.
12. اگر هنگامي كه از لنز استفاده كرديد ديدتان خيلي كاهش يافت يا احساس درد كرديد آنها را از چشمهايتان خارج كنيد و فورا به اپتومتريست يا متخصص چشم مراجعه كنيد.
13. اگر از مواد آرايشي چشمي استفاده مي كنيد ابتدا لنز را به چشم بزنيد و سپس از مواد آرايشي استفاده كنيد.
14. اگر از مواد آرايشي چشمي استفاده مي كنيد ابتدا لنز را از چشم خارج كنيد سپس مواد آرايشي را پاك كنيد.
15. در حالي كه لنز بر روي چشمهايتان قرار دارد هرگز از اسپري هاي معطر كننده استفاده نكنيد.
16. كساني كه در محيط هاي آغشته به مواد شيميايي كار مي كنند كانديد خوبي براي زدن لنز نيستند اما اگر مجبور به استفاده از لنز باشند بايد حتما هنگام كار از عينك هاي محافظ استفاده كنند.
17. اگر لنز سخت زده ايد چشمهايتان را ماساژندهيد زيرا ممكن است لنز بيرون بيافتد.
18. اگر بعد از زدن لنز احساس جسم خارجي كرديد فورا لنز را در آوريد و پس از شستشو با سرم فيزيولوژي مجددا آن را بر روي چشم قرار دهيد.
19. اگر چشمهايتان دچار عفونت - قرمزي - چسبندگي پلك ها و تورم شدند از لنز استفاده نكنيد و به اپتومتريست يا متخصص مراجعه نماييد و تا بهبود كامل از لنز هايتان استفاده نكنيد.
20. اگر به طور اتفاقي لنز نرم را داخل جا لنزي به صورت خشك نگهداري كرديد ابتدا سرم فيزيولوژي را بر روي آن بريزيد و بعد از 4-2 ساعت لنز را برداريد در غير اين صورت دست زدن به لنز نرمي كه خشك نگهداري شده است باعث پودر شدن آن مي شود.
21. از قرار دادن دو عدد لنز در يك جا لنزي جدا خودداري كنيد زيرا باعث چسبندگي مي شود و جدا كردن آنها از هم مشكل خواهد بود.
22. موقع زدن لنز بر روي قرنيه فشار اضافي وارد نكنيد زيرا باعث آسيب به قرنيه خواهد شد.
23. موقع برداشتن لنز مراقب باشيد ناخن هايتان به قرنيه صدمه نزند.
24. هنگامي كه لنز بر روي چشمهايتان قرار دارد از قطره يا پماد چشمي استفاده نكنيد.
25. هنگام خواب لنز را در آوريد و هرگز با لنز نخوابيد مگر اينكه لنز دائمي استفاده كنيد.البته حتي در مورد لنز هاي دائمي نيز توصيه مي شود كه هنگام خواب آنها را از چشم خارج كنيد.
26. هنگام بستن سرپوش ظرف نگهداري لنز مواظب باشيد لنز پاره نشود.
27. برنامه زمان بندي شده توسط اپتومتريست يا متخصص را در مورد زدن و برداشتن لنز رعايت كنيد و هيچ گاه بيشتر از آن از لنز استفاده نكنيد.
28. طبق برنامه اي كه اپتومتريست يا متخصص چشم براي شما مشخص كرده است به طور مرتب براي كنترل چشم و لنز هايتان به او مراجعه كنيد.

Spectacle vs. Contact Lens RX and Prescription Terminology

Glasses sit about 12 millimeters from the eye, while contacts sit directly on the eye surface. These 12 millimeters make a world of difference and can dramatically change the prescriptions between the two. Also, contact lens prescriptions require more specifications than glasses.

What is the difference between contact rx and glasses rx?

Your Two Different Prescriptions

However, contacts and glasses prescriptions are actually slightly different because of their distance from your eyes. Eyeglass lenses are placed approximately 12 millimeters away from your eyes, while contact lenses sit directly on your corneas.

How do I write a prescription for contact lenses?

A written prescription usually includes the following specifications: base curve, diameter, power (or sphere), and then additional figures for Cylinder and Axis if you have astigmatism, and Addition and Dominant figures for presbyopia correction.

What are the different types of eyeglass lenses?

• Concave lenses. These are thinnest in the center. ...
• Convex lenses. These lenses are thickest in the center, like a magnifying glass. ...
• Cylindrical lenses. These curve more in one direction than in the other.

What does +1 mean on contact lenses?

A positive number, for example, PWR/SPH +2.00, indicates hyperopia (long-sightedness). The figure in front of 'Addition' (ADD) determines the correction you need for presbyopia to obtain near-clear vision.

Glasses Prescription explained

A prescription is normally written out by an optometrist like this:

R. -1.00/ -1.25 * 175

The first figure that you will see on an optometrists prescription is the SPHERE (abbreviated Sph). This is the main power of the prescription and represents myopia (shortsighted) when prefixed with a minus sign i.e -1.00, and hypermetropia (longsighted) when prefixed with a plus sign i.e +1.00. Often the Sphere power has a DS after it like this: +3.00DS. The "DS" signifies Dioptres Sphere, which is the unit of measurement for spectacle power.

The next figure you see is the CYLINDER power (abbreviated cyl). This represents the astigmatism in your prescription. Often this figure is shown like this -1.25cyl. Astigmatism is always along a certain angle (axis) from 0 to 180 degrees. i.e -1.00 * 175. Finally the sphere and cylinder power are usually separated by a slash
ie sphere/cylinder * axis The R. signifies the right eye. (L. for the left)

A prescription for glasses forms the basis for a contact lens fitting. If you look at your prescription it will be in a format similar to one of these;

	R. -3.00DS L. -3.50DS This indicates that you are myopia (shortsighted) of moderate degree. Powers can range from -0.25DS to well in excess of -20.00DS. An average power for the myopic population would be about -3.00DS.
	R. +3.00DS L. +3.50DS This indicates that you are hypermetropia (longsighted) of moderate degree. Powers can range from +0.25DS to well in excess of +20.00DS. An average power for the hypermetropic population would be about +3.00DS.
	R -2.00/-1.00 * 35 L. -1.25/ -1.50 * 90 This prescription indicates that you are myopic, plus have a small amount of astigmatism. Astigmatism is best described as an irregularity in the shape of the cornea. The cornea is the clear covering on the front surface of the eye that helps the eye focus. An astigmatic cornea is often said to be shaped like a football. A normal cornea is round like a basketball. The different curvatures on the surface of the cornea cause the light entering the eye to focus at different points causing distorted vision. Astigmatism can affect one or both eyes, and is sometimes coupled with other visual impairments such as nearsightedness and farsightedness (see example below). This example shows a prescription that is shortsighted (the -2.00 part in the right eye), with astigmatism (the -1.00 part). In addition the final figure (35 in the case of the right eye) indicates the axis (angle) of the astigmatism. The axis (angle) can lie between 0 and 180 degrees and indicates the angle of the ovalness of the astigmatism. Low astigmatism would be below 1.00, moderate 1 to 3, and high above 3.
	R. +2.50/ -1.00 * 180 L. +3.25 / -1.25 * 10 This prescription indicates that you are hypermetropic (longsighted), plus have a small amount of astigmatism
	R +2.00/ -1.50 * 170 L. +2.50/ -175 * 180 Add +2.00 Sometimes the prescription will have an ADD power written after it, in particular if you are aged 45 or over. This indicates that you are presbyopic and need a additional power to help you read. You can have presbyopia in addition to any of the prescription above, or you may have only presbyopia and perfect vision otherwise. Interchangeable? A prescription for glasses is different than a prescription for contact lenses although they can be similar. A contact lens comes in direct contact with the cornea, which is the clear covering over the front surface of the eye. For this reason, there are additional measurements needed for fitting a contact lens and these need to be included in the prescription. - the curvature of the cornea - the diameter of the cornea Base Curve (BC) The curvature of the cornea is measured to determine the exact curvature (base curve) of the inside surface of the contact lens. This ensures the lens fits the shape of the eye providing optimum vision and comfort. Diameter (D) The diameter of the cornea is measured and also necessary to find the optimal contact lens diameter. This measurement is fairly straight forward. A contact lens is usually 2 - 4mm larger than the diameter of the cornea. The Same Only Different A contact lens prescription can be the same as a prescription for glasses when: - the prescription is a lower power, ie: -4.00 to +4.00 and - there is absolutely no astigmatism present. If you have any astigmatism or require a lens power greater than +/-4.00, the parameters of the contact lens can change. - if you have astigmatism under 0.50, a spherical lens should be prescribed. - astigmatism of 0.50 to 0.75 can be effectively corrected with an aspheric lens. - astigmatism greater than 1.00 should be managed with a toric lens. If your prescription power for glasses is greater than +/-4.00, you should see a difference in the power of your contact lens prescription. Generally, every time your glasses prescription increases or decreases by a power of 2, your contact lens prescription will increase by an additional power of +0.25. For every power change of 2 in a glasses prescription, the difference of +0.25 power is needed to compensate for the location of the contact lens. Your glasses are much further from the front surface of the cornea than contact lenses. The Eyeglass Rule requires that optometrists and ophthalmologists provide patients a copy of their prescription after the completion of an eye examination without extra cost. Reference: contactlens.co.uk aarp.org/health/conditions-treatments/info-2021/eyeglasses-prescriptions.html visionworks.com/article-difference-between-contact-vs-glasses-prescriptions

Eye-Care Tips for Wearers of Contact Lenses

Though most people probably won't come down with the condition, it's always a good idea to take good care of your eyes and contact lenses to avoid problems such as bacterial infections, which are much more common than fungal infections. Here are some guidelines:

Advice on wearing contact lenses:

• Wear your contact lenses as prescribed. Don't wear them longer than recommended.
• Never wear anyone else's contact lenses.
• Contact lenses may make your eyes more sensitive to sunlight, so wear sunglasses with total UV protection and/or a wide-brimmed hat while in the sun.
• Insert your contact lenses before applying makeup to avoid contaminating your lenses.
• Use a rewetting solution or plain saline solution to keep your eyes lubricated.
• Don't sleep with your lenses in, unless you have "extended wear" contacts.

Advice on cleaning and storing contact lenses:

• Always wash your hands with warm water and soap before handling your contact lenses or touching your eyes.
• Clean and store your contact lenses as prescribed (in a clean case in fresh solution).
• Clean your contact lens case after each use with either sterile solution or hot tap water; let it air dry.
• Never use plain water directly on your contact lenses and never put your contact lenses in your mouth to "rinse" them. Microorganisms can live even in distilled water, causing infection that can threaten vision.
• Clean your contact lens by rubbing it gently with your index finger in the palm of your hand. "No rub" solutions allow cleaning without rubbing.
• Don't let the tip of solution bottles touch other surfaces, including your fingers, eyes, or contact lenses. The solution can become contaminated.

Advice on eye care:

• Look for signs of eye infection, such as redness, burning, or excessive tearing.
• If you develop an eye infection, take your lenses out and don't use them until you talk to your eye doctor.
• See your doctor annually to check your contact lens fit and prescription.
• Visit a doctor immediately if you have any degree of sudden vision loss, blurred vision, light flashes, eye pain, infection, swelling, unusual redness, or irritation.

Top 10 Tips for contact lenses

1. Always wash your hands

Hand hygiene is essential, always wash your hands with soap and water, then rinse them before handling your contact lenses or touching your eyes. Dry your hands using a lint-free cloth or paper towel.

2. Do not sleep in lenses

Unless advised by your eye doctor, always remove your lenses before you go to sleep, take a shower, or go swimming.

3. Never use water

When you remove your contacts, be sure to rinse and gently rub them with the lens solution that your eye doctor recommends. Never use tap water or saliva to clean or wet your lenses!

4. Replace the lens storage case

Keep your contact lens case clean by washing it with warm water and soap every week. Replace it every month.

5. Do not over wear

Only wear your contact lenses for the recommended time and days of the week, as instructed by your eye doctor.

6. Makeup

If you wear makeup, try to avoid applying any makeup to the inner portion of your eye, where it can cause irritation. Mascara and eyeliners can infect your eyes and the contact lenses.

7. Backup glasses

Always carry a back-up pair of glasses, in case your eyes need a break from your contacts. Even if you wear your lenses on a full-time basis, ask your eye doctor for an inexpensive pair of backup glasses, as there will be times when wearing your lenses is just not possible.

8. Red eyes

Never wear your contacts if your eyes feel irritated or appear red. Wait until full eye comfort is restored before inserting them. Never hesitate to contact your eye doctor if you have red or irritated eyes, before wearing contact lenses.

9. Do not share

Never share your contact lenses with anyone, even family members. Whether your contact lenses are purely cosmetic or to correct vision — don’t let them touch anyone else’s eyeballs.

10. Your eye doctor is your friend

If your eyes or contact lenses are giving you any trouble, contact your eye doctor without delay.

SOURCES: Associated Press. American Optometric Association: "Clinical Guidance Regarding Fungal Keratitis Associated with Contact Lens Wear from the American Optometric Association Contact Lens & Cornea Section." WebMD Medical Reference provided in collaboration with The Cleveland Clinic: "Eye Health: Caring for Your Contact Lenses."

Reference:

• medicinenet.com/script/main/art.asp?articlekey=60957
• optometrists.org/general-practice-optometry/optical/guide-to-contact-lenses

To find answers to your contact lens questions just click on a topic below

Important Questions to Always ask your Eye Doctor
Soft Contact Lens Care and Handling
Soft Lens Insertion
My Lens Sticks to My Finger When Trying to Insert it
Toric Lens Insertion
Soft Lens Removal
How Do I Tell if my Lens in Inside Out?
Avoiding Eye Infections
Symptoms of Eye Infections
Swimming with Contact Lenses
Blurry Contact Lenses
Tearing (Ripping) Your Contact Lenses?
Good Habits for Soft Contact Lenses
Bad Habits for Soft Contact Lenses
Contact Lens "Do's" and "Don'ts"
Tips To Increase Contact Lens Comfort
Contact Lens Discomfort
Corneal Swelling (Edema) From Over Wearing Lenses
Troubleshooting Soft Contact Lenses
Options for the Bifocal User
Disposable Contact Lens Use
Extended Wear Contact Lens Use
Makeup and Contact Lenses
Contact Lens Care
Avoiding Contact Lens Problems
Tips for Total Comfort
What to Do When You Have a Problem: What To Do Right Away
What to Do When You Have a Problem: When To Seek Medical Care
Finding a "Lost" Lens
Contact Lens Related Problems
Lens Comfort Problems
Wearing Time Problems
Vision Problems
Contact Lens Allergy
Lens Deposits
Other Potential Contact Lens Problems
Contact Lens Complications
Corneal Ulcer
Corneal Warping
Corneal Swelling (Edema)
Giant Papillary Conjunctivitis (GPC)
Eye Redness

Related Topics:

• 5 Tips For a Smooth Transition to Contact
• Color Contact Makeup Tips
• Common Contact Lens Problems Tips
• Contact Lens - Tips & Tricks
• Contact Lens Care Tips
• Contact Lens Costs Tips
• Contact Lens Makeup Safety Tips
• Contact Lens Makeup Tips
• Contact Lens Solution Recall Advice

Reference:http://www.besteyeglasses.net

لنزهای تماسی قطعات کوچک پلاستیکی هستند که بر روی قرنیه چشم قرار داده می‌شوند، و دید چشم مبتلا به عیوب انکساری را تصحیح می‌کنند.

زمانى كه شما با مشكل بينايى روبه رو هستيد، عينك معمول ترين راه حل است.

اگر مى خواهيد از لنز تماسى استفاده كنيد، چند انتخاب در پيش رو داريد:

لنزهای سخت ، لنزهای نرم روزانه ،لنزهای توریک ، لنزهاى نفوذپذير غيرقابل انعطاف ، لنزهای یکبار مصرف ، لنزهای طولانی مصرف

• لنزهاى سخت: اين لنزها توسط كمتر از يك درصد افرادى به كار مى رود كه از لنز تماسى استفاده مى‌كنند. اين لنزها از پلاستيك سخت ساخته شده‌اند و ديد واضح و دقيقى ايجاد مى كنند. اما استفاده از اين لنزها، اكسيژن رسانى به قرنيه را دشوار مى‌كند و در نتيجه به جاى اينكه اكسيژن خون از ميان قرنيه عبور كند، از اطراف آن مى‌گذرد.

تطبیق‌ یافتن با اين لنزها از ساير انواع لنزها دشوارتر است و غالباً عادت کردن به آنها به چند روزى زمان نياز دارد. امروزه لنزهاى سختى كه به اكسيژن اجازه عبور نمى‌دهند، تقريباً ديگر به كار نمى‌روند.

The first choice when considering contact lenses is which lens material will best satisfy your needs. There are five types of contact lenses, based on type of lens material they are made of:

Contact Lens Material

• Soft lenses are made from gel-like, water-containing plastics called hydrogels. These lenses are very thin and pliable and conform to the front surface of the eye. Introduced in the early 1970s, hydrogel lenses made contact lens wear much more popular because they typically are immediately comfortable. The only alternative at the time was hard contact lenses made of PMMA plastic (see below). PMMA lenses typically took weeks to adapt to and many people couldn't wear them successfully.
• Silicone hydrogel lenses are an advanced type of soft contact lenses that are more porous than regular hydrogel lenses and allow even more oxygen to reach the cornea. Introduced in 2002, silicone hydrogel contact lenses are now the most popular lenses prescribed in the United States.
• Gas permeable lenses — also called GP or RGP lenses — are rigid contact lenses that look and feel like PMMA lenses (see below) but are porous and allow oxygen to pass through them. Because they are permeable to oxygen, GP lenses can be fit closer to the eye than PMMA lenses, making them more comfortable than conventional hard lenses. Since their introduction in 1978, gas permeable contact lenses have essentially replaced nonporous PMMA contact lenses. GP contacts often provide sharper vision than soft and silicone hydrogel contacts — especially if you have astigmatism. It usually takes some time for your eyes to adjust to gas permeable lenses when you first start wearing them, but after this initial adaptation period, most people find GP lenses are as comfortable as hydrogel lenses.
• Hybrid contact lenses are designed to provide wearing comfort that rivals soft or silicone hydrogel lenses, combined with the crystal-clear optics of gas permeable lenses. Hybrid lenses have a rigid gas permeable central zone, surrounded by a "skirt" of hydrogel or silicone hydrogel material. Despite these features, only a small percentage of people in the U.S. wear hybrid contact lenses, perhaps because these lenses are more difficult to fit and are more expensive to replace than soft and silicone hydrogel lenses.
• PMMA lenses are made from a transparent rigid plastic material called polymethyl methacrylate (PMMA), which also is used as a substitute for glass in shatterproof windows and is sold under the trademarks Lucite, Perspex and Plexiglas. PMMA lenses have excellent optics, but they do not transmit oxygen to the eye and can be difficult to adapt to. These (now old-fashioned) "hard contacts" have virtually been replaced by GP lenses and are rarely prescribed today.

• لنزهاى نرم روزانه: اين لنزها از جنس پلاستيك پليمرى نازكى است كه با شكل چشم شما همخوانى دارد.

برخلاف لنزهاى تماسى سخت، لنزهاى نرم به اكسيژن - كه براى سلامت قرنيه ضرورى است - اجازه عبور مى‌دهند.

اين لنزها از لنزهاى سخت و يا لنزهاى انعطاف ناپذيرى كه به اكسيژن اجازه عبور نمى‌دهند، انعطاف پذيرتر بوده و شخص از همان ابتدا احساس راحتى بيشترى خواهد كرد. زمان تطبیق یافتن با اين لنزها كوتاه‌تر است و بهتر بر روى قرنيه قرار مى‌گيرند و براى فعاليت‌هاى ورزشى و زندگى پرتحرك مناسب‌تر هستند.

انواعى از لنزهاى نرم كه به لنزهاى توريك مشهورند، در تصحيح موارد خفيف تا متوسط آستيگماتيسم به كار مى‌روند.

لنزهاى نرم به اندازه لنزهاى سخت يا لنزهايى كه در برابر اكسيژن نفوذپذير هستند، دوام ندارند، اما از لنزهاى نرم يك بار مصرف بيشتر عمر مى‌كنند. اين لنزها برخى مشكلات بينايى مانند درجات شديد آستيگماتيسم را تصحيح نمى‌كنند.

• لنزهاى نفوذپذير غيرقابل انعطاف (RGP): اين لنزها از پلاستيك سخت با سوراخ هايى ساخته شده اند كه نسبت به لنزهاى نرم، حتى اجازه عبور مقادير بيشتر اكسيژن را مى دهند. اين لنزها در تصحيح طيف گسترده اى از مشكلات بينايى بسيار عالى عمل مى كنند و پس از گذراندن دوره تطابق، كاربرد آنها براى اغلب افراد، آسان خواهد بود.

مراقبت از لنزهاى RGP آسان بوده، كمتر از لنزهاى نرم سبب عفونت مى شوند و بيشتر از آنها هم دوام دارند. همچنين نسبت به لنزهاى نرم، ديد واضح تر و بهترى ايجاد مى كنند. از معايب اين لنزها يكى اين است كه بايد هميشه بر روى چشم باشند و ديگر اينكه راحت تر از مركز چشم ليز مى خورند و به كنارى مى روند.

• لنزهاى يك بار مصرف: اين لنزها در انواع يك روزه و يا طولانى تر وجود دارند. بسته به نوع و چگونگى مراقبت از آنها، مى توان براى يك روز تا سه ماه - در ساعات بيدارى - قبل از دور انداختن، از آنها استفاده كرد.

You may want to have the perfect look for Halloween or look like your favorite movie star or singer, but choosing to change the look of your eyes with contact lenses could cause a lot of damage to your eyesight if you get them without the input of your eye care professional.

Decorative contact lenses are sometimes called, among other names:

• Halloween contact lenses
• Fashion contact lenses
• Colored contact lenses
• Cosmetic contact lenses
• Theatre contact lenses

Decorative contact lenses change the look of your eyes. They may not correct your vision. They can temporarily change your brown eyes to blue or make your eyes look like cat eyes or vampire eyes for Halloween.

Did you know that these decorative contact lenses are actually medical devices? The U.S. Food and Drug Administration oversees their safety and effectiveness, just like contact lenses that correct your vision.

Just like corrective contact lenses you should never buy contact lenses from a street vendor, beauty supply store, flea market, novelty store or Halloween store—and you should always have a prescription.

Before stepping out with your new look, here's what you need to know.

رايج ترين توصيه در مورد زمان تعويض لنز، پس از دو هفته است. مزاياى اين لنزها مانند ساير انواع لنزهاى نرم است. اما از آنجايى كه لنزهاى يك بار مصرف معمولاً قبل از رشد ميكروب و يا افزايش پروتئين به دور انداخته مى‌شوند و از لنزهاى روزانه نازك تر بوده و منافذ بيشترى براى عبور اكسيژن دارند، كاربرد آنها از لنزهاى نرم معمولى ، آسان تر است.

معايب اين لنزها مشابه لنزهاى نرم معمولى است، گرچه لنزهاى يك بار مصرف شكننده تر بوده و كار با آنها دشوارتر است. لنزهاى يك بار مصرف بايد هر روز تميز و ضدعفونى شوند. حتى زمانى كه مورد استفاده قرار نمى‌گيرند، بايد حداقل هفته اى يك بار تميز و ضدعفونى شوند.

• لنزهاى طولانى مصرف: اينها لنزهاى نرمى هستند كه مى توانند براى بيش از ۲۴ ساعت به طور مداوم روى چشم باقى بمانند. اين لنزها به گونه اى طراحى شده‌اند كه حتى در زمان خواب هم اكسيژن قرنيه را تامين مى‌كنند و قبل از درآوردن از چشم و تميز كردن مى‌توانند تا يك هفته بر روى چشم باقى بمانند.

اخيراً لنزهاى طولانى مصرف جديدى را مورد تاييد قرار گرفته‌اند كه مى‌توانند هم روزها و هم شب‌ها به مدت سى شبانه روز به كار روند. اين لنزهاى جديد از هيدروژل سيليكون ساخته شده‌اند كه نسبت به لنزهاى يك بار مصرف معمولى اجازه عبور مقدار بيشترى اكسيژن را مى‌دهند.

استفاده از لنز در زمان خواب - حتى اگر لنز طولانى مصرف باشد- شانس عفونت قرنيه را بالا مى برد. مطالعات نشان مى دهد كه خطر عفونت و ساير مشكلات با بر چشم داشتن لنز در زمان خواب، تا ده برابر افزايش مى يابد.

Most contact lenses sold in the US today are either daily disposable, 2 week disposable or monthly disposable lenses.

• Daily wear contacts. eResearch by Navid Ajamin -- spring 2009
• Extended wear contacts.
• Spherical contacts.
• Toric contacts.
• Multifocal / bifocal.
• Monovision contacts.
• Rigid gas permeable (RGP) lenses.
• Hard lenses.

Specialized Uses of Contact lenses

Conventional contact lenses correct vision in the same way that glasses do, only they are in contact with the eye. Two types of lenses that serve a different purpose are orthokeratology lenses and decorative (plano) lenses.

Currently, FDA requires that eye care professionals be trained and certified before using overnight Ortho-K lenses in their practice. You should ask your eye care professional about what lenses he or she is certified to fit if you are considering this procedure.

Reference:

• aut.ac.ir
• allaboutvision.com/contacts/contact_lenses.htm
• fda.gov/medical-devices/contact-lenses/types-contact-lenses

20 Contact Lens Care and Handling Tips

1.) Wash and Dry Your Hands – Not once but every time you handle your contacts. Even during removal. Use warm soapy water and a clean towel. Much of the dirt, grime and gunk comes from the wearer.

2.) Only use lens cleaners and drops that your eye care professional has suggested.

3.) Follow directions: the directions from the lenses, the lens cleaners, the drops and from your eye care professional.

4.) Clean your contact lens case after every usage. Let dry before use. Get rid of the lens case every month.

5.) Look at your contact lenses before applying them. If they flare out instead of looking like a cup, they’re inside out.

6.) Don’t change contact lens solutions or drops without clearing it with your eye care professional.

7.) Use makeup that is safe for contact lenses.

8.) Don’t use water to clean your lenses; even distilled water may have tiny varmints.

9.) This should be obvious – don’t spit on your lenses or put them in your mouth to clean them - cleaning your contact lenses isn’t like coming up to the plate in a baseball game.

10.) Don’t mix contact cleaning solutions.

11.) Take your lenses off before swimming or entering a hot tub.

12.) Don’t sleep in your daily or non-extended wear contacts. Even a nap could lead to problems. When you’re sleeping it is more difficult to get oxygen to your eyes. Your contact lenses may also become dry and stick to your eyes.

13.) Don’t wear any lenses past their expiration date. Dailies are for one day, not two.

14.) If you develop any eye issues - redness, itching or blurry vision – take the contact lenses out and call your eye care professional.

15.) Don’t wear someone else’s contact lenses. Even with non-prescription color lenses, you don’t know where their eyes have been.

16.) Contact lenses make a wearer’s eyes more sensitive to sunlight. Wear sunglasses or a nice hat when out in the sun.

17.) Keep eyes lubricated with a rewetting solution suggested by your eye care professional.

18.) Put in contacts before applying makeup. This will make it easier to avoid contamination.

19.) Remove your contacts before removing makeup.

20.) Don’t let the tip of the solution bottle touch anything, not even your fingers. If the tip of the bottle becomes contaminated the solution may become contaminated.

Ask your eye care professional if you’re confused about what you should do.

Reference: justeyes.com/contact-lenses/articles/20-contact-lens-care-tips.html

ميليونها نفر در جهان از لنزهاي تماسي استفاده مي كنند . لنزهاي تماسي بسته به روش زندگي و انگيزه شما مي تواند موقتاً جايگزيني براي عينك باشند.

لنز تماسي چيست ؟ لنزهاي تماسي كه به آنها عينك هاي نامرئي نيز گفته مي شود ، صفحه هاي پلاستيكي انحنا دار ، مدور ، نازك و شفافي مي باشند كه بر روي قرنيه قرار گرفته و بر لايه اشكي كه قرنيه را مي پوشاند ، شناور مي شوند . سلامت قرنيه و لايه اشكي براي راحتي و وضوح بينائي شما در هنگام استفاده از لنزهاي تماسي بسيار مهم است . لنزهاي تماسي براي اصلاح شرايط زير بكار مي روند :

1-     نزديك بيني ( ميوپي )

2-     دوربيني ( هيپروپي )

3-     آستيگماتيسم منظم

4-     قوز قرنيه ( كراتوكونوس )

انواع مختلف لنزهاي تماسي

كارخانه هاي متعددي در سراسر دنيا انواع مختلفي از اين لنزها را توليد مي كنند ،‌ ولي به طور كلي به دو دسته تقسيم مي شوند كه شامل لنزهاي سخت و نرم مي باشند .

لنزهاي سخت  

اين لنزها از نظر قوام ، سفت بوده و قابل تا شدن نيستند و از نظر جنس مواد سازنده به دو دسته تقسيم مي شوند :

1- لنزهاي تماسي PMMA  ، كه امروزه به ندرت استفاده مي شوند.

 2- لنزهاي سخت با قابليت نفوذپذيري نسبت به گاز اكسيژن(RGP) : اين لنزها شامل تركيبي از پلاستيك و ساير مواد از قبيل سيليكون يا پليمرهاي فلوئور مي باشند . اين مواد علاوه بر حفظ شكل لنز ، اجازه عبور اكسيژن را از ميان لنز به قرنيه مي دهند. اين لنزها رطوبت پذير بوده و نسبت به ساير لنزها قدرت سازگاري بالاتري با قرنيه دارند. لنزهاي RGP بهترين انتخاب در موارد آستيگماتيسم بالاي قرنيه و بيماري قوز قرنيه مي باشند . استفاده از اين لنزها طبق نظر پزشك و در بيماراني كه لنز نرم براي آنها مفيد نمي باشد ، تجويز مي گردند. اين دسته از لنزها به علت سختي ماده اوليه لنز قابليت انعطاف ندارند ( مثل لنزهاي نرم تا نمي شوند ) و به همين دليل مدت زمان بيشتري لازم است تا فرد به آنها عادت كند.

لنزهاي نرم :

اين لنزها نرم و قابل انعطاف بوده و تحمل آنها راحت تر است و داراي انواع زير هستند :

1-     لنزهاي با مصرف روزانه : اين لنزها ارزان ترين نوع هستند و شب در هنگام خواب برداشته شده و صبح روز بعد مجددا در چشم گذاشته مي شوند . حداكثر زمان استفاده از اين لنزها 12 تا 18 ماه مي باشد ، بعد از گذشت اين مدت بايستي لنز عوض شود .

2-     لنزهاي با مصرف دراز مدت : اين لنزها در طول شبانه روز قابل استفاده هستند يعني مي توانيد شبها با لنزها بخوابيد اما حداقل هفته اي يكبار براي ضد عفوني و تميز كردن برداشته مي شوند . به دليل مصرف شبانه روزي و افزايش خطر عفونت قرنيه ، استفاده از انها كمتر توصيه مي شود . مدت زمان مجاز براي استفاده از اين لنزها حداكثر يكماه مي باشد.

3-     لنزهاي يكبار مصرف : اين لنزها گرانتر ولي راحت تر و مناسب تر هستند. اين لنزها هر شب برداشته شده و صبح روز بعد گذاشته مي شوند و بر اساس نوع ، به صورت هفتگي يا ماهانه دور ريخته مي شوند . با اين لنزها مي توان بر حسب ضرورت شبها خوابيد ولي به همان نسبت از عمر لنز كاسته مي شود. استفاده از اين لنزها در موارد حساسيت بيمار ارجحيت دارد . لنزهاي رنگي و توريك مي توانند از اين نوع باشند .

4-     لنزهاي توريك : اين لنزها قادر به اصلاح آستيگاتيسم هستند ، اگرچه گاهي به خوبي لنزهاي RGP عمل نمي كنند ولي معمولا كمي گرانتر از ساير لنزهاي تماسي مي باشند و در ميزان اصلاح آستيگماتيسم محدوديت دارند.

5-     لنزهاي رنگي : اين لنزها مي توانند رنگ و ظاهر چشم را تغيير دهند . لنزهاي رنگي خود انواع مختلفي دارند كه عبارتند از : لنزهاي رنگي مرئي ، تشديد كننده ، مات و فيلتر كننده نور . بسياري از اين لنزها فقط جنبه زيبايي داشته و برخي ديگر از آنها براي اصلاح عيوب انكساري ، تغيير نماي ظاهري قرنيه معيوب يا كاهش ناراحتي ناشي از نور بخصوص بعد از ضربه هاي چشمي به كار مي روند .

6-     لنزهاي بانداژ : استفاده از لنز به عنوان بانداژ يا پانسمان ، براي پوشاندن سطح قرنيه بعد از ضربه ، جراحي يا در برخي بيماريهاي خاص با نظر پزشك صورت مي گيرد . اين دسته از لنزها به علت توانايي در نگهداشتن اكسيژن و آب به مدت طولاني در بافت خود، در التيام زخمهاي قرنيه تاثير بسزايي دارند .

How to Insert a Contact Lens

Inserting soft contact lenses can be exasperating for new users. Just when they think they are done, the lens pops out because it is too dry or inside out. By following a few simple steps, new users will be inserting and enjoying their contact lenses just like long time contact lens wearers.

Instructions

Things You’ll Need:

• Soft contact lenses
• Contact lens case
• Contact lens solutions

Step 1:

Prepare the work area. Most people insert contact lenses in the bathroom. Be sure to use a cleaner to sanitize the bathroom counter or vanity. Arrange the lens case and solutions for easy reach.

Step 2:

Ready yourself. Push up long sleeves. Contact lens solutions can roll down the hands and arms. Wash your hands thoroughly and dry with a clean towel. Plan to spend a little time. New users typically need 5 to 10 minutes until the procedure is learned.

Step 3:

Open the contact lens case. Remove one lens using the index finger. Apply a few drops of rinsing solution. Balance the lens on the fingertip.

Step 4:

Examine the edges of the contact lens. They should point upward as if ready to cup the eye. If the edges are flat, the lens is inside out. Flip it over.

Step 5:

Control blinking. Raise and hold the upper eyelid using one finger from the free hand. With the other hand, extend the index finger that holds the lens. Use the middle finger next to it to draw down the lower lid.

Step 6:

Look directly into the contact lens. Carefully place it on the center of the eye. For an alternative method, look upward toward the ceiling. Lightly touch the lens to the white of the eye.

Step 7:

Remove the fingertip. Gently let go of the lower eyelid followed by the upper lid. Close the eye. Count to 5. If the lens feels dry, insert a few drops of rewetting solution. Insert the other contact lens using the same procedure.

Tips & Warnings

• After inserting contact lenses, wash the case and let it air dry.
• Never place a contact lens in the mouth.
• Don't use saliva or tap water to rewet a contact lens. Only use sterile saline or contact lens solutions.
• Never share contact lenses.

Reference : ehow.com