Eyedolatry

How to Keep Anti-Reflective Coatings from Peeling and Scratching

Do your glasses lenses look like this?

I've often had patients return with several year old lenses (or even newer if they are rough on their glasses!) with lenses that are scratched and coatings that are distorting. For many of these patients, their frustration with the loss of performance out of their lenses tempts them into wanting to replace their lenses without anti-reflective coating protection. Typically the surface distortions and scratches on glasses with light use are on that top layer of anti-reflective coating, and not deep into the plastic lens material itself. But if you have ever had glasses made without anti-reflective coating, you know that you are compromising performance greatly by having sheets of glare that form across your eyes every time you are exposed to light. Here are the best ways that you can have that glare protection, but keep your glasses performing at their highest even years into their lifespan!

Do I need Anti-Reflective Coating?

Coatings are softer than the plastics underneath, so they are easier to distort or scratch. If you are thinking about compromising by going without glare coatings on your next pair, ask yourself these questions first:

Do you drive at night?
Do you use a computer often during the day?
Do you work in fluorescent or bright lighting?

Do you have a prescription of +/-4.00 or higher?

AR coatings are about a lot more than how you look in
photographs. If you work around back-lit devices, you
know that the glare off the screen shining across your eyes is a
leading cause of end of day fatigue. Keep your eyes feeling
fresh on digital devices and computers by investing in specific
blue-blocking AR coatings. via

If you answered yes to any of these questions, your glasses will perform significantly better if you purchase anti-reflective coatings with your glasses. Anti-reflective coatings prevent oncoming light from headlights or computer screens from causing sheets of glare across your glasses. Light hits your lenses and instead of reflecting back across your eyes, it instead becomes absorbed or negated by the coatings in place. The best performing anti-reflective coatings cover the full spectrum of visible wavelength light. If you are a computer user or night driver, I highly recommend specific blue-wave length reducing AR coatings like Crizal's Prevencia or HOYA's Recharge that are designed to reduce that annoying LED screen glare off your electronic devices and reduce end of day fatigue. Wouldn't you like to feel less eye strain at the end of your day? If you answer yes, you need anti-reflective coating.

How to Protect Anti-Reflective Coating?

So I know that what I'm about to say may be hard to admit, but anti-reflective coatings don't just peel by themselves. The best way to prevent your glasses from scratching and peeling is to take care of them properly. Yes, these coatings are softer and easier to scratch than plain plastic, but being consistent and vigilant in your care will keep your glasses performing for years. Here are some basic rules to follow:

Only Clean your Glasses with the Right Materials

Tempted to clean your glasses on your coat or shirt? Don't! Yes glasses will smudge as you go through your day, especially if you frequently touch them or around your face. Oils from your skin will easily collect and smear on the lenses. For myself, I lean into a microscope multiple times a day, so my glasses always have the rubber microscope eyepiece smudges to remove. But if you clean your glasses with the wrong materials, you will eventually scratch and wear away the surface coatings. NEVER clean your glasses with tissue paper, rough washcloths, Kleenex, or paper towels. These materials are much too rough and will wear away a surface coating fast. Kleenex and paper towels are made from wood fibers, so if you reach for one, just imagine rubbing your glasses with a stick from outside. That's basically what you are doing. Your doctor's office will almost always provide free cleaning cloths and sprays for you to use so that you can keep a few in a purse or desk drawer. If you don't have access to lens cleaning cloth, then the only at-home material you should use would be an old soft cotton t-shirt (something that is several years old and through multiple wash cycles works best) and just a small amount of diluted Dawn dishwashing detergent will work in a bind. That's it -- don't try any other do it yourself options. Never clean your glasses with alcohol or alcohol based soaps! These will strip away the coatings very quickly if you use them consistently.

via

Are you frequently cleaning your glasses but hate carrying around a cloth and lens spray? Try out a premium lens cleaner like the Peeps by LensPen, small enough to fit in your pocket or even as a key chain, and it will clean your glasses of smudges instantly without any risk of scratching since it uses ionic attraction to pull oils and smears from your lenses without any rubbing across the surface. You can read more here.

Avoid Extreme Temperatures

Many people will lead their sunglasses or driving glasses in their car, but be warned, extreme heat will break down your coatings with time and cause peeling and distortion. If you have to leave your glasses in your car, make sure you have them in a case and try to park your car in a covered deck or under some shade to reduce high temperature exposure. If you are consistently exposing your glasses to extreme temperatures, just expect that you may need to replace your glasses more consistently as well. Professions like chefs or kitchen workers who expose their glasses to high temperatures and steam may have to replace their glasses more regularly as a result.

Take Home

The average AR coating should last about 2 years in my experience under moderate temperature and cleaning abuse,but if you are exposing your glasses to more extremes they could break down within a few months. Invest in a lens warranty if your work environment is more demanding or you know that you aren't consistently good with cleaning your glasses the right way. Most vision insurances provide benefits towards new lenses on a yearly or every 2 year basis, so replacing your glasses on that timeline should suffice for most. If you want lenses to last for longer, then your best bet is to follow these guidelines carefully every day. I have had AR coated lenses that have lasted for over 5 years now without signs of distortion, so with proper and diligent care it is possible!

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1 Pair of Sunglasses, 2 Ways to Wear

2015 eyewear fashion trends 7:00 AM

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Multifocal Contact Lenses: The Basics for Starting Your Fit

basic contact lens fitting evaluation multifocal lenses 8:21 AM

1. Start with a Current Glasses Rx

If it's been a few months since their last exam, or you are fitting from another practitioner's prescription, it is well worth re-refracting the patient to ensure that the spectacle correction is up to date.
Binocular balancing the prescription means you will start with the maximum plus that can be tolerated in each eye for equality of vision.
If astigmatism is at play, determine the best vision sphere. Pay particular attention to any indication that the patient may be uncomfortable having vision fogged when astigmatism is removed in a particular eye. This could predict that distance vision may be unacceptable in soft multifocal lenses, and a toric lens or specialty lens would be needed.
Another important consideration is the patient’s habitual working distance; this should be taken into account when fine-tuning the near addition. Longer working distances are helpful to be aware of when addressing near needs in the lens.
As always, make sure you vertex the distance for prescriptions over ±4.00DS when you select your initial lens. In some multifocal lenses vertexing may not give you the best distance starting place, so make sure you follow the guide for the lens you are starting with.

2. Determine Eye Dominance

Ocular dominance is defined as ‘the superiority of one eye over the other in some perceptual or motor task." Superiority of function doesn't necessarily mean that eye has better vision than the other eye.
Ocular dominance can be measured in two ways:

The Hole in Hand technique is often
used for gun training also (via)

Motor Dominance: A common way to measure this is the "hole in the card" test where a patient holds an index card at arm's length with a small hole cut in the center, and then with both eyes open moves the hole so that a distance letter on the chart is centered inside. The doctor then occludes each eye alternatively, and the dominant eye is the one that can see the letter when the other eye is occluded. This can also be done by having the patient make a small hole with their two hands, and sighting a letter through that.
Sensory Dominance: This is the preferred method for many practitioners since it relies less on patient compliance. Having the patient wear their best corrected prescription and looking at the distance chart, hold a +1.50 trial lens over one eye and then the other. The dominant eye is the one that suffers the most noticed blur when viewing the chart binocularly.

If your patient spends more time at near than distance, and is more concerned with clarity of near vision, it may also be of benefit to determine near sensory dominance. To do this, repeat the procedure above with a near card and add -1.50 trial lens to each eye. The dominant eye at near will be the one that suffers the most noticed binocular blur when the -1.50D trial lens is introduced before it.
If distance and near sensory dominance differ, then this patient is a great candidate for monovision or multifocal contact lenses. If their dominant eye is the same for both distance and near, you may want to consider making the dominant eye set for the activity the patient deems most important to their day (be that distance or near).

It will be much harder to achieve clear vision without a toric contact lens if the dominant eye has significant amounts of astigmatism. Soft multifocal lenses can potentially mask up to -1.25D of cyl, but on the dominant eye it is much more difficult to achieve clarity with anything over -0.75D.
In the initial multifocal contact lens selection, equality of vision is the aim so ocular dominance may not initially come into play. As adjustments are needed, and in those patients who have a moderate or high reading addition, ocular dominance becomes a useful tool in finding a happy medium to vision.

3. Assess the Ocular Surface with a Slit Lamp Exam

Recent research has estimated that the dropout rates for multifocal contact lenses are 15.9 per cent in the US, 31 per cent in Asia. The biggest reason for CL dropout in those over 40 years of age is poor comfort, followed by inconvenience and reduced vision. Decreased comfort is typically due to changes in our tear chemistry at this time of life, typically a result of dry eye and eyelid chemistry

Tear Break Up Time is assessed by viewing
the time it takes for tear film to break up and
evaporate off the eye. It should ideally take around
10 seconds for tear film to distort via

dysfunction. If not appropriately managed, these issues can lead to symptoms of foreign body sensation, burning, itching, watering,and fluctuating or decreased vision --symptoms that mirror the everyday complaints of contact lens wearers.
Check for:

Blepharitis
Meibomian gland dysfunction(MGD)
Tear Break Up Time: This quick assessment is a common measurement for Dry Eye Syndrome. A tear film break up of less than 10 seconds indicates tear film instability. It can be assessed at the slit lamp with fluorescein dye or with a topographer.

4. Set Expectations Before Any Contact Lens Touches The Eye

It is useful to determine what tasks the patient performs in an ordinary day and to fit the lenses accordingly. Success in soft multifocals is seldom a matter of achieving 20/20 vision, as it typically is with distance only contact lenses. Even when the Snellen acuity is not what it would be in spectacles, multifocal contact lenses allow patients to function well without having to wear spectacles. People vary hugely in their adaptation to and tolerance of blur. It is important to remember that one person may think they see great with 20/30 vision, and another could be really unhappy with their vision but see the 20/20 line.

As a part of the discussion with patients regarding multifocal lenses, it is wise to point out that there may be limitations to what can be achieved. The mantra is that multifocal lenses will fulfill most of a patient’s visual needs most of the time. As practitioners we should never underestimate what may deemed as successful by any patient as it is both a subjective and patient-specific decision.

This is a generic example of the way multifocal lenses deliver vision to the eye. Because the patient will be receiving vision in multiple rings, clarity can be a major issue, and halos or ghosting is expected! via

5. Assessing your Initial Contact Lens Selection

The fitting characteristics of soft multifocals differ significantly between manufacturers, as well as between individual wearers. Due to their relative design complexity, multifocal contact lenses should not be issued to patients without them first having a proper lens fitting. The initial lens you select based on glasses prescription may provide acceptable vision or very poor vision, depending on the patient's brain responds to the image delivery of the lens. Aim for a minimum of 20/30 vision with ghosting for distance vision in any initial lens that is dispensed.
All manufacturers provide fitting guides for their products. Make your life easy by selecting the initial trial lenses according to the manufacturer’s fitting guide.

You can find popular lens fitting guides like Biofinity MF and Air Optix MF here on the site, as well as several daily MF fitting guides!

Allow the initial trial lenses to settle for about 15 minutes before evaluating them. Encourage the patient to browse around the practice in this time -- judging real world vision instead of letters on the chart is better to initially let the patient experience. Many manufacturers suggest that initial evaluation of vision should be subjective. Ask the patient how they feel their vision is with the lenses. Distance and reading vision should be assessed binocularly. Discourage the patient from comparing each eye individually because it will always look worse this way in multifocals!
If the patient reports dissatisfaction with vision then over-refraction can commence to improve vision. Again, this should be done with both eyes open, with the room lights on. Start with small ±0.25 changes. When possible, an over-refraction should be confirmed outside the consulting room looking at a distance target. Better still, take the patient outside and confirm any distance over-refraction.
Improvements to near vision should also be performed using ±0.25 steps, ideally while performing a task on a smart phone or tablet.
Keep changes to distance and reading to a minimum and always confirm any change to ensure that correcting one area of vision does not have a detrimental effect on the other. It is also worth remembering that multifocal contact lenses are adaptive. It will take a few days before the patient is fully adapted to their new visual environment and things that seemed difficult to see on day one may be much easier by the end of a week. So don’t rush into early changes when, given time to adapt, the patient may well be happy with that first prescription.
Subjective scoring can be very useful when assessing when to change or not. As a general guide, when asked to score their distance vision and near vision out of 10 after the initial walk about with the lenses, anything less than seven needs working on before they leave the practice.
In most cases, maintaining comfortable distance vision is paramount, especially for critical distance tasks such as driving. In these instances it may be necessary to consider a part-time reading prescription over the contact lenses for very small print or prolonged reading.

6. Assess the Lens on the Eye

The fitting of a multifocal lens should appear the same as any other soft contact lens. The lenses should center well, show good post-blink movement and have a smooth return on push-up. The wettability of the lenses should also be noted.

Conclusion

The fitting of multifocal contact lenses is very rewarding, creates positive patient perception that may result in referrals, and is a great practice builder. The latest generation of lenses are much easier to fit than their predecessors and the first time success rate is very high.

Confidence in fitting increases with practice and inevitably there are going to be a number of failures. It is important to remember that not all patients will be suitable for multifocal lenses. However, don’t give up at the first hurdle. In the same way opticians have access to many designs of spectacle lenses and these are dispensed based on patient need, there are now a number of both daily and monthly design multifocal contact lenses available. If one design doesn’t work, then try another. The fitting guides produced by each manufacturer have been produced after extensive research and it is important that, as well ensuring a good baseline refraction, these guides are followed. With increasing success and confidence will come more challenging fits such as toric multifocals, amblyopic patient fitting, specialized RGP, hybrid and scleral lens types.

This post was submitted by Dr. Aaniket Pangarkar of Goa, India

If you are interested in submitting a post for publication, just email us at eyedolatry@blogspot.com

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Your Eye Doctor's Guide to Reducing Dark Under Eye Circles

best eye cream doctor ophthalmologist 12:14 PM

Even celebrities like Pippa Middelton have to battle eyelid
puffiness and dark circles. Frequent air travel will dehydrate
yourbody, so getting more sleep and staying hyrdated are key if
you live a high stress or frequent flier lifestyle. via

If you are like many men and women in my office, you aren't getting enough sleep, you're spending long hours on the computer, and you are battling an unpleasant mixture of red eyes and dark circles. One of the most common questions I'm asked in the exam room is not about how my patients can see better, but how their eyes can look and feel better. Here's the best doctor recommended approach to bring those dark under eye circles under control, and to feel better about how your eyes are looking behind those great new glasses or contact lenses.

Understanding the Culprit

The key to really understanding how to get rid of dark under eye circles is to understand why they are there. Your eyelid skin is some of the thinnest in your body, only 0.05 mm in thickness compared to places like the palms of your feet which is a whopping 1.5 mm thick. Because this skin is so thin, it is much more translucent to the blood flow underneath. This thin skin is also the reason why muscle twitches are so easy to feel and observe when they happen in the eyelid (see this article for a full explanation of those pesky muscle twitches). Underneath the skin, there are complex and dense layers of vasculature and capillaries, circulating blood and nutrients through the area. If the blood vessels or capillaries are widened or dilated, then they appear much larger under the skin, resulting in a darker appearance to the thin skin lying over top. Common causes of vasodilation?

sleep or inactivation of the sympathetic nervous system (low lights, absence of noises, basically your body at rest)
allergies (histamine responses in the body can cause vasodilation)
alcohol
estrogen (hormone levels fluctuating during pregnancy are a common cause of increased puffiness and dark circles too)
warm environments

Kate at The Small Things Blog shows her pregnancy related darkened under
eye skin pigmentation and puffiness pre-morning make up routine. Many
pregnant women experience increased skin pigmentation along the cheeks
and lower lids, in addition to much more puffiness as fluid is getting retained
in hands, feet, and yes, under the eyelid skin.

No surprise that most people report dark under eye circles are more prevalent when they first wake up. Overnight our sympathetic nervous system is much less active, and we are typically snuggled up under warm covers. The blood vessels will be at their most dilated.

Puffiness usually pairs with that dark purple appearance, and is actually the result of fluid pooling underneath the thin eyelid skin. Water pools in areas of chronic irritation, or when we are retaining more fluid in general (such as during pregnancy or when hormones are fluctuating more). Inflammatory events like crying, allergies, or frequent eye rubbing (even pressing your eye too firmly against your pillow if you sleep on your face counts!) will increase the amount of fluid retained under your eyelid skin and cause morning puffiness.

How to Fix It

The best way to approach dark circles and puffy eyelids is to understand that it is a normal body response -- there's no way to eradicate it, just to minimize it. Getting more sleep and avoiding vasodilators like alcohol late at night can help. If you are in a much deeper sleep when you wake up in the morning, your vessels will be much more dilated because your body was not circulating those sympathetic nervous system hormones and stimulators. By comparison, if you are getting the sleep you need, by the time you wake up you would have already exited that deepest REM sleep cycle and your sympathetic nervous system naturally will be starting to activate as well.

Unfortunately getting more sleep and less late nights isn't always feasible, and you definitely can't control your hormones if they are your root culprit for puffy dark circles. Here are a few key things to try at home for a quick fix:

Use a cool spoon to reduce puffy eyelids by causing
those blood vessels to constrict underneath your thin
eyelid skin via

Constrict those blood vessels with a cold compress for immediate reduction in puffiness and dark rings. Try wrapping a washcloth around an ice cube and holding against the lower lid, or keep a spoon in the refridgerator and gently hold against that lower eyelid socket. the curve of the back of the spoon is a perfect shape for your lower lid, but just don't press too hard,
Have a cup of coffee. Caffeine will immediately jump that sympathetic nervous system into response, resulting in constriction of blood vessels.
Treat your allergies. The under eyelid is a chief reaction spot for allergies, resulting in puffiness and swelling. There are some great OTC and prescription allergy eye drops on the market to minimize irritation, itching, and puffiness.
Don't rub your eyes! Chronic and frequent eye rubbing can cause your skin to get looser and thinner as you manipulate and distort the skin under your fingers. The stronger your skin is, the less those dilated blood vessels and retained fluids will be visible underneath.
Wear sunglasses. If your skin is more darkly pigmented from years of sun exposure, there is no way to reduce the appearance of dark circles. Sun protection from a young age can prevent permanent dark spots on the skin and eyelids.
Stay hydrated. Remember chemistry class where we first learned that osmosis causes water to move to areas that are dehydrated. If you want to keep fluid from building up underneath the eyelid skin and causing puffiness, we need to keep the body and skin hydrated with good daily water intake, and a good topical moisturizer applied nightly won't hurt either.

There are a multitude of great eye creams out there that can also help reduce the appearance of dark under eye circles. As we age, our eyelid skin naturally gets thinner and looser, resulting in wrinkles but also more under eye puffiness because the skin is so easily distorted by even small amounts of fluid underneath. Using a great wrinkle cream and consistent sun protection can help keep skin strong and wrinkle free, helping to reduce puffiness long term. My patients swear by:

Philosophy Miracle Worker: This retinoid based cream helps boost skin collagen amounts to prevent wrinkles and keep skin thick and resistant to puffiness. It also contains peptides to stimulate that essential blood vessels constriction and reduce the appearance of darkness under the eyes.
ORIGINS GinZing Refreshing Eye Cream: This morning cream is a cocktail of natural caffeines and stimulants to get that under eyelid skin and blood vessels awake. The combination of coffee bean extract and gensing gets the job done.
Tarte Maracuja-C Brighter Eye Treatment: Based on a strong mix of Vitamin C and antioxidants, this cream is chiefly a wrinkle protector, but also has oat sugars that help tighten eyelid skin to reduce puffiness.
Shiseido White Lucent Anti-Dark Circle Cream: In addition to ingredients that increase blood vessels circulation and constriction to minimize dark circles, this cream also attacks dark pigmentation from more active melanin production that can result in permanent darkened eyelid skin, either from genetics or old sun damage. It also leaves a reflective top coat after application that helps reflect light and make skin look brighter.

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Red, Irritated Eyes? There Mite be a Problem

chronic styes 7:00 AM

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What is Eye Pressure?

anterior chamber angle 7:00 AM

Hand held tonometers (or intraocular pressure measurers)
can be used on people and animals too to find dangerous
eye pressure ranges! via

We are in the last few days of Glaucoma Awareness Month, so I have dedicated today's post to one of the most commonly asked questions in my exam room: what is eye pressure? Eye pressure or intraocular pressure (which means the pressure inside your eye) is something that is measured at every comprehensive eye examination, but in the general population it's very poorly understood.
Here's an easy guide to what eye pressure is and why your doctor measures it!

Think of your eye like a basketball. The inside of the ball is "pumped up" to a certain pressure to achieve the shape and properties desirable for the ball's performance. While we don't need our eye to bounce, we do need it to have enough of its own pressure to keep its shape. The eye is a relatively soft tissue after all. In addition to having enough pressure to keep the eye's shape and structure, the pressure in the eye also helps with the distribution and flow of nutrients to the intraocular tissue. The eye needs a certain pressure to keep its structural channels open for nutrients to pass through and blood to flow to various areas. So we do need a minimal eye pressure (typically 4 mmHg or more is required for the eye to function), but too much can result in structural damage too. Too little pressure and your basketball deflates, too much and it bursts. Your eye won't burst, but too much or too little can both be devastating to your ocular health and vision!

The front section of the eye is the anterior chamber. Aqueous humor is made
in the ciliary body, and then flows around the lens, through the pupil, and bathes
the back surface of the corneal to deliver nutrients before draining out. via

Common question -- eye pressure is not blood pressure. They are actually completely unrelated (but can interact to put you at higher risk for damage like glaucoma!). The pressure inside the eye comes not from blood flow, but from a clear fluid called the aqueous humor. The front of your eye (or anterior chamber as it is called scientifically) is the area of the eye from your lens forward. This part of your eye needs nutrients and oxygen just like all other parts of your body, but there is a problem: anything between your iris and your cornea (the clear surface dome) has to be clear. If blood vessels covered these

Aqueous humor fluid drains out at the anterior

chamber angle. The angle needs to be open for fluid

to properly drain. If the tissue is blocked here, your

eye pressure will acutely spike really highly! via

areas you would be looking through red lines all the time in your vision. Instead the body uses a clear fluid called aqueous humor to deliver nutrients to the anterior chamber structures. At any moment you have aqueous humor entering the front of the eye and exiting, passing nutrients through the system. The aqueous humor is made by the ciliary body (a structure that surrounds the iris), and is then drained through channels where the iris and cornea meet inside the eye (the anterior chamber angle). If too much fluid is being made, or not enough is draining out, your eye pressure will rise.

This fluid is entirely inside of your eye, so even though we check your pressure by measuring externally, we are reading the internal eye pressure. Just like the pressure inside of the baskteball. If your eye is watering a lot people will often ask me if their pressure is too high. Watering and eye pressure are almost always unrelated, since the fluid that causes high eye pressure is an internal eye fluid and not your tear film that is an external eye fluid.

When intraocular pressure is too high, the long term result is glaucoma, or death of the optic nerve. If fluid is getting backlogged in the eye, it can change and shift the direction of that nutrient flow, even altering the flow of nutrients in the blood vessels in the back of the eye. In time, this destroys the delicate nerve tissue that delivers information from the eye to the brain. Glaucoma is typically a slow process -- you can have acute spikes in pressure that cause sudden damage (acute angle closure glaucoma is an example), but typically glaucoma takes years or decades to cause blinding vision loss. And because in most people it's not the result of an acute high spike in pressure but years of chronic, mild elevation, you would not have any symptoms if you have glaucoma. That's right, you won't feel different; you won't have red eyes; you won't have eye pain; and you won't notice vision problems. Until you do and it is too late. That's why glaucoma is something that we all need to be screened for yearly. Unless your doctor is checking your eye pressure and optic nerve health, you won't know something is wrong until it is too late for us to restore your vision!

What's normal?
Normal eye pressure is typically under 21 mmHg. Normal can vary from person to person however, so for some people even readings in the teens are too high and still damaging their eye. Glaucoma is multifactorial, and there are so many different kind of glaucomas -- some have high pressure and some have perfectly normal pressure readings. As a general rule, if your eye pressure is in the high 20s or 30s, you probably have glaucoma or at least the strong risk of it. Don't expect to feel a pressure sensation in your eyes unless your pressure is in the high 40s or 50s (at risk of acute and rapid vision loss!!). Typically that pressure sensation you feel around the eyes towards the end of the day is actually just eye fatigue from tired eye muscles, but always best to get things checked.

For more information about glaucoma, check out What is Glaucoma? and How Does Your Doctor Check for Glaucoma? for more patient-friendly reading!

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