Monday, April 10, 2017

myopia control

What is myopia?
Myopia is the fancy name for near-sightedness. Myopia causes vision to be blurry in the distance. It is the result of light rays focusing in front of the light-sensitive tissue that lines the back of the eye (the retina) rather than on the retina. This can happen when the power of the front of the eye is too strong (refractive myopia) or when the eyeball is too long (axial myopia). Below is an illustration. A minus (concave) lens is used to focus the light rays on the retina so that images are clear. The most common type of myopia begins between the ages of 6 and 12.

A myopic eye focuses the image IN FRONT of the retina, producing a blurry image. Minus lenses are used to correct myopic eyes, putting the image ON the retina so you can see clearly. 

The prevalence of myopia has been increasing over the past decades. In 2000, 23% of the world's population was myopic, and researchers are predicting that 50% of the world's population will be myopic by 2050 (1). THAT'S HALF OF THE WORLD!! Higher rates of myopia, nearing 90%, occur in some Asian populations. The increase in myopia prevalence suggests that environmental factors play a role in its development, though there is certainly a genetic component as well. People with higher amounts of myopia are also at greater risk for eye health issues such as retinal detachment and myopic maculopathy (2), so the myopia "epidemic" is a public health concern.

How does myopia progress? 
The exact mechanism of myopia development is still unclear. The thought is that myopia progression is caused in large part by the elongation of the eye. Research suggests that peripheral hyperopic defocus causes elongation of the eye. The periphery can be blurred even if the center is clear, and this peripheral blur is not really something we notice. At near, the periphery is more out of focus than it is when looking in the distance, so near work may be implicated in the progression of myopia (3). Some more recent studies have shown a greater association between myopia development and the time spent outdoors than the time spent doing near work. Translation: increasing myopia is more closely related to how little time people spend outdoors than how much time people spend reading. So minimal time spent outdoors could be a risk factor for myopia development. Very recent research has identified a cell in the retina that may cause myopia when it dysfunctions. The dysfunction may be linked to the amount of time spent indoors/away from natural light (4).
image: Review of Optometry

Options that have been shown to slow the progression of myopia:
  1. Orthokeratology (aka ortho-K, corneal reshaping technology, CRT). These are customized contact lens worn only at night, temporarily changing the shape and power of the front part of your eye (the cornea).  When you wake up, you take the contacts out and you can see! Ortho-K lenses involve reverse geometry, meaning the curves of the lens are structured so that the tear film beneath the lens essentially flattens the center of the cornea while steepening the midperipheral cornea. This creates peripheral myopic defocus that negates the peripheral hyperopic defocus that is linked to eyeball growth (5). Orthokeratology is FDA approved for myopia up to -6.00D and mild amounts of astigmatism (up to 1.75D). There is no minimum age; the child just has to be able to put the contacts in, take them out, and maintain them on their own. It all depends on the child's maturity level. As with any contact lens wear, there is a small risk for infection. Studies have found that ortho-K treatment produced an average of 30-50% reduction in the progression of myopia.(6). Ortho-K appears to be more effective for those with higher amounts of myopia and larger pupils. Both the LORIC and later the CRAYON study showed that ortho-K slowed the axial growth of the eye, thus reducing myopia progression (7). The SMART study is yet another recent study that supports the theory that ortho-K reduces myopia progression. At the conclusion of this 3-year study, the ortho-K group saw an average increase in myopia of 0.12D while the soft lens control group increased by an average of 1.01D (8).
  2. Soft multifocal contact lenses. Multifocal contact lenses are those that correct your distance while also giving you plus power to help see up close when needed. The specific design of multifocal lenses that are used for myopia control are center distance design (see image below). Center distance means more plus power in the periphery of the lens, which decreases peripheral hyperopic defocus and induces peripheral myopic defocus, reducing axial elongation. Several study results have supported the use of distance-center soft multifocal contact lenses for myopia progression, averaging a 40% reduction in myopia progression (91011)The CONTROL study found a whopping 72% reduction in progression of myopia over a one year period when compared to wearing single vision soft contact lenses (12), though this study involved myopic children with a specific focusing/postural issue (eso-fixation at near).

  3. A multifocal lens with a center-distance design
    image: Review of Optometry

  4. Atropine. This method is different from the above two because it is not about changing the stimulus that contributes to eye elongation, but rather interfering with a biochemical pathway.  How does it work? We don't really know for sure. But it is thought to act on the white part of the eye (the sclera) or the tissue that lines the back of the eye (the retina) to prevent the sclera from thinning or stretching (13). If you have had your eyes dilated during an eye exam, the doctor likely used tropicamide.  This drop made your pupils big and your vision up close was blurry for 3 or 4 hours. Atropine is a similar drop from the same family of drugs, but the effects last for much longer. Atropine 1% has been shown to produce a 90% average reduction in myopic progression, from 0.5 D/yr to 0.05 D/yr (14). The downside: blurry near vision, light sensitivity, and large pupils. Other studies have shown comparable results using lower concentrations of atropine, which produce less side effects. Atropine 0.01% has been shown to slow myopia progression by 50%(1516) Pirenzepine has also been tested, showing slightly less efficacy (44%), but with fewer side effects. Unfortunately, it's not commercially available as an eyedrop or gel in the US. More research is being done on the long-term effects of atropine therapy, and whether or not its effects are permanent.

Options that are NOT GREAT for slowing the progression of myopia:
  1. Undercorrection of myopia. I've had some parents specifically ask me to give their child less powerful glasses in hopes that that would make the child need glasses less. There is no validity to this claim; actually, the undercorrection of myopia has been shown to INCREASE its progression (171819).
  2. Progressive addition lenses (PALs). Commonly called "no-line bifocals," PALs are lenses that have your distance prescription at the top and gradually become more plus-powered as you go vertically down the lens. Many people over the age of 40-ish wear these to help them see clearly at all distances. For the purposes of myopia control, they're not a top option. The COMET study found a small, statistically significant decrease in myopia progression in children wearing PALs vs children wearing regular, single-vision lenses, but only in the first year. So the conclusion was yes, it produces a little decrease in progression, but not enough to warrant a change in how we prescribe for myopic children (20). Also, other aspects of the child's binocular vision should be taken into consideration. 
  3. Spherical soft contact lenses or rigid gas-permeable (RGP) contact lenses (aka regular distance vision contacts). These two choices are excellent forms of vision correction, but they have shown little value in terms of controlling myopia progression. The CLAMP study showed some reduction in myopia with RGPs in year 1 in comparison to soft contact lenses; however, it was not clinically significant because it didn't change axial length and was likely due to the flattening of the cornea, which is not permanent (21).

CliffsNotes: Glasses and regular contact lenses don't help slow myopia progression. Undercorrection of myopia doesn't help either; it actually makes it worse. Atropine therapy, orthokeratology, and soft multifocal contact lenses have been shown to be effective in controlling myopia progression. Ask your optometrist for more information!


Additional recommended resources:

Tuesday, January 31, 2017

meibomian gland dysfunction

image: All About Vision
What are meibomian glands?
Meibomian glands are sebacous (oil) glands located in the upper and lower eyelids. There are more in the upper lid than the lower lid, and they are also larger in the upper lid (1). The glands sit vertically in the eyelids, and their openings are right behind the lash line. The job of the meibomian glands is to make and secrete oil. These secretions make up one of the 3 layers of the tear film, the lipid layer. Blinking helps spread the secretions on the surface of the eye, keeping the tear film stable and preventing it from evaporating too quickly. The function of the glands is regulated by hormones such as androgens, estrogens, and progestins. 

A visibly capped meibomian gland
What is MGD?
Meibomian gland dysfunction, or MGD, is not the most clearly defined condition.  Here's the technical definition:

"Meibomian gland dysfunction (MGDis a chronicdiffuse abnormality of the meibomian glands,commonly characterized by terminal duct obstruction and/or qualitative/quantitative changes in the glandular secretion. It may result in alteration of the tear filmsymptoms of eye irritation, clinically apparent inflammationand ocular surface disease." (2)  

Translation? MGD is when the meibomian glands don't work right. The dysfunction is typically either a result of a blockage in the gland or an abnormality in the oil being secretedA blockage may present as a clear or opaque dome at the opening of the glands (see photo above). MGD can also involve changes in the quality and quantity of secretions. When pressure is applied to normal glands, they should secret a small amount of clear oil. In the case of MGD, the secretion is thicker and more yellow-white in color. I liken it to when you leave a tube of toothpaste open for a while, and you get some crusty, solidified gunk at the opening that you have to squeeze out to get to the usable toothpaste. 


What are the signs and symptoms of MGD?
Some common symptoms include dryness, a sandy/gritty feeling, a burning sensation, eye and lid irritation, contact lens intolerance, eyelids sticking together in the morning, and even blurry vision. These symptoms are also symptoms of similar but distinct conditions, so a thorough examination of the eyelids, tear film, and front surface of the eye by an eye doctor is warranted to help identify what the source of the issue is. 

Common associated signs of MGD are thickened eyelid margins, frothy tears, and a low tear break-up time (the time it takes for the tear film to break up due to evaporation). In fact, dysfunction of the meibomian glands is one of the main causes of evaporative dry eye disease. Not only does it cause dryness, but insufficient lipids may cause increased bacterial growth on the lid margins, which can cause a number of secondary lid issues (2).


What is MGD associated with?
  • Age: MGD increases in prevalence with age (3).
  • Contact lens wear: Studies suggest a decrease in functional meibomian glands with contact lens wear (4, 5).
  • Ethnicity: MGD appears to have a much higher prevalence among Asian populations (2). 
  • Systemic factors: menopause, rosacea, Sjogren's syndrome, etc. 

How is it treated?
There are various treatment options available, depending on the severity and associated symptoms/signs.  Here is a list of treatments I typically recommend for MGD, going from least complex (for milder cases) to most complex. 

1) BLINK! Blinking stimulates the secretion of meibum, and helps spread it across the surface of the eye. Studies show you blink less when reading, and you blink 60% less when at the computer (6).  So take frequent breaks, and make a conscious effort to blink completely during those breaks.
2) Warm compresses with lid massage. Taking a page out of a colleague's book, it's the flossing of the eye world- it's something you SHOULD do daily to prevent disease, but not a lot of people do it religiously. 
  • Use a warm washcloth (or a boiled egg or warmed dry rice wrapped in a cloth- somethng that stays warms for a few minutes) and rest it over your eyelids with your eyes closed. Do so for at least 5-10 minutes. Gently massage your eyelids, rolling your fingers vertically down your upper lid and up your lower lid (towards your lashes). This helps get the oils flowing normally, and also helps remove any solidified gunk at the opening of the glands.
  • I recommend doing this twice daily when symptoms are present, or when MGD is first diagnosed. Beyond that, once daily is great for maintenance.
  • Follow up with a lid cleanser, gently scrubbing along the lash line to remove debris, makeup, and bacteria that may clog or infect the oil glands. A cleanser containing diluted tea tree oil is particularly beneficial if Demodex is present. 
Lipiflow is an in-office procedure that accomplishes the same thing, though more effectively.  The device heats the internal surface of the lids and simultaneously applies pressure to the external lid to express the glands, all in about 12 minutes. 

3) Omega-3 fatty acids. Omega-3s help improve the quality of the oil produced by the meibomian glands, and they have anti-inflammatory effects. A great source of omega-3s is fatty fish, like salmon and tuna. Another option is fish or flax seed oil supplements. It's always a good idea to consult with your doctor before starting any supplement.

4) Artificial tears can also help beef up the contents of the tear film.  Lipid-based artificial tears are best in the case of MGD because they help replenish the lipid layer of the tear film, and not just the aqueous layer. Some lipid-based drops: Systane Balance, Soothe XP, Retaine MGD, and Refresh Optive Advanced. 

5) Prescription medications.  Depending on the other presenting conditions, some patients with MGD may require the use of antibiotics. Topical azithromycin or low-dose, long-term use of oral doxycycline are thought to alter the eyelid bacteria and also provide anti-inflammatory effects (7, 8). Still others with severe MGD may need to have the inflammation controlled through the short-term use of a topical steroid drop or the long-term use of a dry-eye drop. 


CliffsNotes: MGD can alter the makeup of the tear film, leading to eye irritation, inflammation, and dry eye. So see your eye doctor STAT to nip it in the bud!

Additional Resources:

Thursday, December 8, 2016

central retinal vein occlusion

What is a CRVO?
A central retinal vein occlusion (CRVO) occurs when there is an obstruction of the central retinal vein, which is the main vein of the retina (the tissue that lines the back of the eye). A blood clot, or thrombus, may occur in the vein as a result of abnormalities in blood vessel size, blood composition and/or blood flow.

Veins carry blood back to the heart. When the main vein that drains the retina is blocked and blood cannot flow out, the blood builds up and leaks out of the walls of the vessels.  This leakage causes the retina to swell (retinal edema).  When fluid leakage occurs in the area of the retina called the macula (macular edema), central vision is impaired.  

We'll be talking specifically about central retinal vein occlusions in this post, but you can also have a branch retinal vein occlusion (BRVO), which affects a smaller vein, or a hemi-retinal vein occlusion (HRVO), which affects either the upper or lower half of the retina. It all just depends on the location of the blood clot. 

A CRVO can be classified as non-ischemic or ischemic.  Ischemic means there is a shortage of oxygen due to a reduced or restricted blood supply.  When ischemia exists in the retina, vascular endothelial growth factors (VEGF) are released. VEGF stimulates the growth of new, abnormal blood vessels (neovascular membranes) to help supply the retina with the necessary oxygen and nutrients.  This is bad, because those blood vessels are weak and leak. In the case of ischemic CRVOs, the abnormal vessels can cause a serious type of glaucoma, called neovascular glaucoma. This results in dangerously high eye pressure that is very difficult to treat. Fortunately, most cases (about 75%) of CRVOs are non-ischemic, which is the less serious form and involves less severe vision loss.  
Photos of a non-ischemic CRVO of the right eye
What are the symptoms and signs?
The most common presentation is sudden, painless loss of vision in one eyeWhen the eye doctor looks in the affected eye, he/she will see lots of hemorrhages (see photos) in all 4 quadrants of the retina and possibly cotton wool spots, which are fluffy white spots in the retina. The veins of the retina are widened and curly. There may also be swelling of the optic disc. CRVOs are sometimes described to have a "blood and thunder" appearance, because it pretty much looks like something exploded in the back of the eye. 
CRVO photo via Wills Eye
What are the risk factors?
CRVOs usually occur in persons over the age of 50, and hypertension is the most common systemic association. Other vascular diseases like atherosclerosis, high cholesterol, and diabetes are risk factors as well.  Hardening and/or narrowing of the arteries can compress the vein and cause clot formation.  Open angle glaucoma is also a risk factor.  If a CRVO occurs in someone under 40 years of age with no known risk factors, he/she may need to be tested for blood clotting or thickness abnormalities

How is it treated?

The blockage cannot be undone, so the goal is to treat/prevent the secondary complications. Namely, macular edema and neovascularization. Several clinical trials have shown there are treatment options that help reduce macular edema and improve vision to a certain degree. Early detection of complications and timely treatment are key.  

The most common treatment for macular edema as a result of a CRVO is intravitreal injections of anti-VEGF drugs. The drugs are injected into the gel part of the inner eye (the vitreous), and are usually administered every 4-6 weeks.  Two such drugs that are FDA-approved for treating macular edema due to CRVOs are Lucentis (ranibizumab) and Eylea (aflibercept). Avastin (bevacizumab), a cancer drug, is an anti-VEGF drug used extensively as well, though used off-label. Steroid injections/implants may be used instead of or in addition to anti-VEGF injections. An intravitreal steroid implant, Ozurdex, is an FDA-approved treatment for macular edema secondary to vein occlusion. Currently in FDA trials: a combo of Eyelea (intravitreal anti-VEGF injection) and Zuprata (suprachoroidal steroid injection) that has the potential to decrease the number of Eyelea injections a patient needs (read more about it here). Laser is not a common treatment with CRVOs, unless there is neovascularization present.

Macula OCT of the above-photographed CRVO patient
Aside from taking photos to help monitor the condition, your eye doctor may utilize other tools in the treatment process. 

  • Optical coherence tomography (OCT) is a scanning laser used to get a cross-sectional image of the retina (see scan above).  This helps assess the level of swelling in the macula and track the response to treatment.  
  • Fluorescein angiography (FA) is used to identify areas of the retina with poor/absent blood flow and helps guide treatment. A dye is injected into a vein in the arm and photos of the retina are taken as the dye reaches the retinal vessels.


CliffsNotes:  A CRVO occurs when a blood clot blocks the outflow of blood from the tissue that lines the back of the eye (the retina). If you notice a sudden, painless loss of vision, contact your eye doctor STAT!


Wednesday, October 19, 2016

Demodex

What is Demodex?
Demodex is an 8-legged, microscopic mite. Two species live on humans: Demodex folliculorum, which are found in the eyelash follicles, and Demodex brevis, which are found in the sebaceous (sweat) and meibomian (oil) glands. These mites live primarily on the face and feed on skin cells and oil in the follicles and glands. They avoid sunlight and live for about 2 to 3 weeks. How common are they? Fairly common in adults (studies report they are found on the skin of 20-80% of adults- that's a pretty wide range and not a super helpful stat...), and nearly 100% of elderly people have the mites on their skin (1). Studies have shown that the prevalence of Demodex increases with age, and Demodex mites are present in higher numbers in those with rosacea, compromised immune systems, and possibly contact lens wearers (23).


Two D. folliculorum on a plucked eyelash (A) and one hanging solo (B)
image: JKMS

Fun (or disgusting) fact: Demodex mites have no anus. Their waste is stored in the gut and expelled when they die, which may cause additional inflammatory response. Shout-out to one of my patients who shared that fact with me. #mypatientsaresmarterthanme

Demodex being teased out of the follicle (arrow) via lash rotation
image: Optometry and Vision Science

What problems can Demodex cause?
Many people have Demodex mites on their skin and have no symptoms or complications. However, Demodex overpopulation (demodicidosis) has been linked to (not necessarily causative of) skin conditions such as blepharitis, rosacea and perioral dermatitis, as well as meibomian gland dysfunction, dry eye, recurrent chalazion, and ocular surface inflammation (45).

Demodex mites can cause problems by clogging hair follicles and sweat ducts, causing abnormal thickening and growth of the epithelial cells at the lid margin. Further, the exoskeleton and waste of the mites can cause an inflammatory response (67). Overpopulation of Demodex mites has been linked to an increase in the presence of certain cell-signaling proteins (cytokines, specifically interleukins) in the tears, which can cause an inflammatory or immunological response (8).

The presence of cylindrical dandruff or "waxy sleeves" around the base of the eyelashes is a very good indicator of demodicidosis. Symptoms may include itching and redness of the lid margin, loss of lashes or misdirected lashes, as well as burning or irritation.

Cylindrical flakes that are highly suggestive of demodex
image: Review of Optometry

How do you get rid of the little buggers?
Frequent scrubbing of the lids with diluted tea tree oil (TTO) was found to be the most effective way to eradicate Demodex and improve patient symptoms (9). The TTO has ingredients (namely, terpinen-4-ol) that kill mites and ticks while also luring the mites out of the hair follicle before they mate (10).  There are also lid wipes, scrubs and shampoos containing various concentrations of TTO that can be used for at-home treatment and long-term maintenance. It is best to keep the concentration of TTO at or below 50%; any higher than that may be too irritating (11). Your eye doctor may choose to add an antibiotic and/or steroid ointment or drop to the treatment as indicated, depending on what other symptoms and signs are present. 


CliffsNotes: If you suffer from dry, itchy, irritated, red, and/or crusty eyelids, have your optometrist take a look. You MITE (see what I did there?) have a Demodex party going on in your eyelashes. 


Additional Recommended Resources:

Thursday, September 22, 2016

the contact lens case

As eye care professionals, we talk a lot about the proper care of contact lenses, but we probably don't spend enough time talking about the proper care of the contact lens CASE. Sure, it doesn't actually go ON your eyeball, but it does matter! The contact lens case can act as a reservoir for microorganisms and can be the source of eye infections, with the contact lens serving as the vector.  Some microbes can attach to the case and secrete substances that create an extracellular matrix-type protective encasement called a biofilm. This allows adherence to biological tissue, plastics, medical devices, etc. The ideal environment for biofilms to attach and grow is a moist surface, which makes contact lens cases prime real estate (1). 

So how should you be taking care of your contact lens case?

1. Change the case AT LEAST every 3 months.  Look at the photos below. Crystal violet stains protein and DNA, the primary components of cellular debris.  You can see that the intensity of the staining correlates with the age of the lens case (2). The longer you use the case, the more bacteria and debris collects, which increases your risk of infection.


image: RCCL

2. Clean the case daily by rubbing and rinsing with fresh contact lens solution (not water). A study found that 52% of those questioned cleaned their cases with tap water (3).  Why is that bad?  Because tap water contains microorganisms that can lead to rare but serious eye infections, like Acanthamoeba keratitis. In another study, cleaning cases with tap water was found to be associated with a higher rate of contamination with gram negative bacteria (4). Multipurpose solutions are designed to interfere with the cell membrane of microorganisms and kill them. Hydrogen peroxide-based solutions use a different method to disrupt the microbial membrane, as well as the DNA and other cellular components (5).  

3. Wipe the contact lens case with a clean tissue, and place the case upside down to air dry in a clean area (ie: not inches from the toilet). Simply rinsing with contact lens solution is not enough to destroy biofilms; mechanical disruption is needed (37).  More bacterial contamination was found to occur in humid environments, most notably when the case was left to air dry face up (8).  So the research tells us that the most effective way to clean your contact lens case is to rub and rinse the contact lens case with fresh contact lens solution daily, wipe the case with a clean tissue, and leave it face down on a clean surface to air dry (910).  

The proper way to store your case: upside down on a clean tissue.

4. Be sure to keep the contact lenses themselves clean!  More on that in a previous post.

Even better yet? Get rid of the case all together and opt for daily disposable contact lenses. You put them in in the morning, remove and discard them in the evening, and start with a fresh pair the next day. Talk to your optometrist to see if those are an option for you.

CliffsNotes: Rub and rinse the contact lens case with fresh contact lens solution (not water) daily, dry with a clean tissue, and leave upside down on a clean tissue to air dry. RUB, RINSE, TISSUE-DRY, AIR-DRY. Replace the case at least every 3 months. 

Additional Resources:


Thursday, September 1, 2016

the history of eyeglasses

A few weeks ago, I saw a 16 year old patient that was interested in optometry as a potential career path. He asked a few questions about the field and schooling, then he asked me a question that stumped me: "When were glasses invented?"

::Crickets:: I am admittedly not a history buff, but this was one I probably should have known. So this blog post is for you, inquisitive teenager S.

When were eyeglasses invented?
Short answer: In the 1200s.

Long answer: The invention of the eyeglass is thought to have occurred in Italy between 1268 and 1289. The use of glass as a means of enhancing vision was mentioned in a few manuscripts around this time. One such mention was in a book by Robert Grosseteste printed in 1235. It referenced using a glass to “read the smallest letters at incredible distances.” In 1268, the English philosopher Roger Bacon wrote: "If anyone examine letters or other minute objects through the medium of crystal or glass or other transparent substance, if it be shaped like the lesser segment of a sphere, with the convex side toward the eye, he will see the letters far better and they will seem larger to him. For this reason such an instrument is useful to all persons and to those with weak eyes for they can see any letter, however small, if magnified enough."

In 1289, Sandra di Popozo wrote in a manuscript: "I am so debilitated by age that without the glasses known as spectacles, I would no longer be able to read or write. These have recently been invented for the benefit of poor old people whose sight has become weak." In 1306, a monk of Pisa delivered a sermon in which he stated: "It is not yet twenty years since the art of making spectacles, one of the most useful arts on earth, was discovered. I, myself, have seen and conversed with the man who made them first." Thus, we conclude that eyeglasses arrived on the scene in the mid-1200s.

The first artistic rendering of spectacles was found in a fresco of Cardinal Hugo of Provence painted by Tommaso da Modena around 1352.
Tomasso da Modena's painting
image: History of Information

In their early days, glasses were worn primarily by monks and scholars. They were essentially two pieces of glass or crystal riveted together, with the lenses bound in leather, metal, or bone. They were either held in front of the eye or balanced on the nose. It wasn't until the invention of the printing press around 1440-1450 that eyeglasses became a common item.

Early spectacles, framed in leather
image:AAO Museum of Vision

The idea of attaching ribbons of silk to the frames and looping them over the ears emerged in the 17th century by Spanish spectacle makers. This idea made it over to China by way of Spanish and Italian missionaries. The Chinese modified this, adding little ceramic or metal weights to the string to hold it in place behind the ear, instead of using a loop. Edward Scarlett, an optician in London, is credited with creating the rigid sidepiece that rested over the ears in 1730. Thus, the spectacle temple was born.
Edward Scarlett's trade card, the first advertisement of rigid temples 
image: The College of Optometrist Museyeum
Martin's Margins 
image: AAO Museum of Vision
Binocles-ciseaux, or scissor-glasses, reached the height of their popularity in the latter half of the 18th century. George Washington and Napoleon Boneparte are said to have used these.
Scissor-glasses 
image: AAO Museum of Vision
Another form of spectacles that came about in the 18th century was the lorgnette, a pair of lenses that were held in front of the eyes by a side handle. These may have developed from the scissor-glasses. Created by George Adams, lorgnettes often had ornate and embellished handles, as they were worn mostly by fashionable women.
The lorgnette (everyone should have a fan attached to their specs) 
image: AAO Museum of Vision
The monocle, interestingly called an "eye ring," become popular in the mid to late 1800s, though they are thought to have developed in Germany earlier. The monocle was most often worn by upper class men. And, of course, Mr. Peanut.
The monocle- who wore it best?
image:Wikipedia
The 1800s saw the oval frame shape come to prominence, as well as the emergence of bifocals. Benjamin Franklin is widely credited for the invention of the bifocal in the 1780s, though the jury is still out on that one.  B.M. Hanna (Hannas unite!) received patents for the cemented and perfection bifocals in the late 1800s.

Pince-nez is a style of glasses that came about in the 1840s. French for "pinch nose," these specs literally pinched the nose and usually had a chain that attached to a lapel or dress. President Teddy Roosevelt was often pictured wearing these. (Aside: check out this interesting story about how President Roosevelt's eyeglass case helped him dodge a bullet.)

Speak softly and carry a big stick. And wear your pince-nez.  
image:Wikipedia
Another interesting tidbit for my eye nerds out there: J. J. Bausch emigrated to the US from Germany in 1850. He had apprenticed with an optician and came to America in search of better opportunity. He set up shop in NY as an optician, and struggled for many years. He sought a $60 loan from his friend, Henry Lomb, and Lomb became an apprentice under Bausch. Bausch created frames out of vulcanized rubber, which were stronger and less expensive than the current metal, animal horn, or wood frames out there. Demand for the product increased, and J.J. Bausch and Henry Lomb eventually went on to build the Bausch and Lomb Optical Company. For those of you that may not know, Bausch and Lomb still exists today, making it one of the oldest continuously operated companies in the US (more info here and here).

The 1900s saw eyeglasses become stylish in addition to functional. A wider variety of eyeglasses were available, and the stigma around wearing eyeglasses was beginning to fade away. Movie stars became style icons, and their glasses were part of their image. Sunglasses also became popular in the 30s. Progressive addition lenses (PALs) were invented in the 50s.
Comedian Harold Lloyd, "the man who popularized eyeglasses in America," wearing his iconic horn-rimmed glasses.
image: Wikipedia

And here we are, in the present, where eyeglasses are considered part of a person's wardrobe, an accessory even. Some old trends are coming back, and some new ones are being created. There are now more eyeglass styles and colors than you can dream of, and they are such a fun (and useful) form of self-expression.

CliffsNotes: Eyeglasses were invented in Italy in the 1200s. They've come a long way since then. :)

Sources
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Thursday, July 14, 2016

4 reasons NOT to buy glasses online

four-eyed cupcakes

Every now and then, I have patients tell me that they plan on buying their glasses online.  I can certainly understand why that would be appealing: low prices, large selection, and ease.  In our drone-delivery, instant-gratification culture, convenience is king!  I, personally, am all about finding cheaper prices from the comfort of my Snuggie (before you start judging, it's a Buzz Lightyear Snuggie).  However, knowing what I know about vision and eyewear, I would urge you to think twice before buying glasses online.  In pursuit of convenience and ease, we forgo the knowledge and expertise of the eyecare professional team in precisely fitting and knowledgeably selecting our eyewear.  This blog post is my attempt to "let the buyer beware."

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Here are 4 things to consider when looking into buying eyeglasses online:

1. Questionable lens accuracy and quality. For me, this is the biggest reason to avoid buying glasses online.  A recent study of internet eyewear orders found that nearly half (44.8%) of the glasses examined had incorrect prescriptions or safety issues:
  • Nearly three out of 10 pairs (29%) of glasses ordered online had at least one lens that failed to meet the required prescription.  When you buy a pair of glasses from an optometrist's office or optical, someone typically checks the lenses for accuracy and quality before the glasses are dispensed to you.
  • Nearly a quarter (23%) of the lenses failed impact resistance testing, which highlights a major safety issue.  Children’s glasses performed even worse, with 29% failing impact testing. (1)
Quality and safety are a big deal, as is prescription accuracy.  These are not areas where you want to cut corners.  At a very minimum, you need to be sure that the power in your lenses is the power on your prescription.  I have had more than a few patients come in complaining about the glasses they bought online, only to find that the prescription in their lenses is in fact not the prescription I wrote for them.  And there's more to it than just having the prescription correct; you can still have headaches, eyestrain, and problems seeing even if the numbers match.

Beyond having the correct power in your lenses, you also need to be looking through the right part of the lens to see clearly and comfortably.  The optical center of your lens should be placed right in front of the center of your pupil.  For the maker of the glasses to know where exactly to put the lens within the frame to achieve that, an accurate pupillary distance is needed.  Multi-focal lenses (lenses that allow you to see at more than one distance, like bifocals or progressive addition lenses) involve additional measurements and powers; fitting multifocal lenses is a careful process and should definitely be done by experienced professionals.  The segment height is a specific measurement for multifocal lenses, and it needs to be measured while you are wearing the frame, with the frame positioned where you normally wear it.  Both the pupillary distance and the segment height are very important measurements that influence what part of the lens you are looking through, and what power you are getting when looking through that part of the lens.  The more complicated the prescription, the more crucial it is to consult with experienced professionals.  Some forms of optical correction, especially for children, are prescribed as part of a treatment for a condition, such as accomodative esotropia or accomodative insufficiency.  If given the incorrect treatment, the condition will not be effectively treated.  After all, glasses are considered Class 1 Medical Devices by the Food and Drug Administration (FDA).  Glasses are not just an accessory; they require a precise prescription and accurate measurements to enable you to see clearly and comfortably.

2. Lack of customization.  Health care should be pursued in-person, because it should be tailored to the individual.  What you need in eyewear depends on your specific prescription and visual needs.  A conversation with your optometrist and optician about such things should happen in order to build a pair of glasses that gives you the best vision and comfort for your daily life.  Do you use a computer all day?  Do you drive for a living?  Do you knit?  Do you play golf?  Now more than ever, there are SO many choices in terms of lens types, materials, and coatings; it really is important to speak with a knowledgeable expert to help you navigate the options and decide on what products suit your visual needs and increase your visual comfort.

3. Lack of input in selecting an appropriate frame.  Frame selection is both an art and a science.  Did you know frames have sizes?  Glasses are NOT one-size-fits-all.  If glasses don't fit properly, you can experience physical as well as visual discomfort.  Aesthetically speaking, certain frame shapes look better on certain face shapes.  But more importantly, there are some frame sizes and styles that should be ruled out based on your prescription and/or the type of lens you need. A trained optician can tell you what frames to avoid.  The way a frame looks certainly matters, but there are many other factors to consider when choosing a frame for your lenses.

4. Customer service.  This is by no means a rule, but in general, the smaller the shop, the better the customer service. There are typically only a few degrees of separation, if any, between you and the manager or owner. You have a person to go back to if you are having any issues with your glasses, or if you need a frame adjustment. I believe human interaction is SO important to building business relationships and creating loyalty. Maybe I'm an old soul, but it's just not the same as clicking around on a website or calling a 1-800 number.

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Every pair of glasses purchased online is not a disaster.  But I would suggest that you as a consumer consider service and quality as well as price and convenience.  Glasses are an investment, and you want your money to go towards a pair that fits properly and comfortably, and provides you with the best possible vision. If you choose to purchase your eyeglasses online, be informed and may the odds be ever in your favor! :)


CliffsNotes: Glasses are not one-size-fits-all accessories. A team of eye care professionals can help you choose a frame and lenses that are ideal for you, considering your prescription and visual needs.  In my opinion, the convenience of ordering glasses online is not worth the potential compromise in accuracy and quality.


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