Eye Didn't Know!

Happy Birthday, Mary Cassatt

Did you know? Today is the birthday of one of my favorite artists, Mary Cassatt (1844-1926), an American Impressionist who exhibited in Paris at the original Impressionist shows, and was a close friend of Edgar Degas. She influenced many prominent American Industrialists to collect Impressionist art, which is one reason Impressionism is well represented in American museums today. Cassatt suffered from cataracts, and probably diabetic eye disease, and stopped painting entirely during the later years of her life. If you compare her later paintings with her earlier ones, the later ones suffer greatly from coarseness and lack of detail, which is why she stopped painting.

(self-portrait, courtesy of Wikipedia Commons and Metropolitan Museum of Art)

Did you also know? The San Diego Museum of Art has a lovely Cassatt work, Simone in a Blue Bonnett.

Longer, Thicker, Darker Eyelashes With Latisse®

Did you know? Latisse® is the new prescription medicine for growing longer, thicker eyelashes. Patients are already coming to my office and asking for it. The aesthetician in my office has been using it for a number of weeks and already reports a noticeable difference in her eyelashes.

Latisse® was developed because of a side-effect of a commonly used eyedrop for glaucoma. I can always tell if these patients are using their drops because their lashes are thicker and longer! Allergan decided to reformulate this medicine into a liquid which can be applied to the base of the upper eyelashes. In their clinical trial of 278 patients, 79% of patients noted thicker, longer and darker lashes at week 20 compared to 20% using a placebo. The majority noted improvement after two months. 

The eyelashes gradually return to their baseline appearance after discontinuing the medicine.

There is a theoretical side-effect of permanent darkening of the iris (the eye color), though this did not happen in the clinical trial, and is unlikely to occur if the medicine does not enter the eye. There is also the theoretical side-effect of reversible skin darkening, but this did not occur in the trial either.

Did you also know? Allergan, the makers of Latisse®, also make BOTOX® and Juvederm®. I enjoy using all of these products in my practice, and my patients enjoy looking younger, with a natural appearance.

Macular Degeneration and Cataract Surgery

Did you know? For many years it has been controversial whether having cataract surgery could accelerate the development of advanced macular degeneration. Some patients have cataract surgery, and not long after, develop worsening of their macular degeneration. Patients, of course, will often blame the cataract surgery. (I have at least one patient who falls into that category). What confounds this logic, though, is that cataracts occur with aging, as does macular degeneration. Patients may experience macular degeneration worsening with or without having had cataract surgery.

At last a well-designed study has addressed this question. The Age-Related Eye Disease Study (AREDS) was conducted between 1992 and 2005 and followed over 8,000 eyes of over 4,000 patients. The study was designed to assess the effect of antioxidants and mineral supplements on macular degeneration. The study assessed the development of advanced macular degeneration and history of cataract surgery at six month intervals during the study.

The results showed that appromately 20% of the eyes underwent cataract surgery during the study. Of the eyes undergoing surgery, 6% developed severe macular degeneration. Of the eyes not undergoing surgery, 7% developed severe macular degeneration. The results of the two groups did not significantly differ statistically.

It can be safely said that modern cataract surgery in unlikely to be related to worsening of macular degeneration.

Did you also know? The AREDS study originally found that their combination of zinc and antioxidants (now found in Ocuvite and others) modestly reduced the risk of progression for eyes with early signs of macular degeneration. The AREDS II study, ongoing now, is investigating the possible roles of omega-3 fatty acids, lutein, and zeaxanthin. It is also investigating if the dosage of zinc can be reduced and whether beta-carotene can be eliminated (for safety reasons in some patients).

Botox® Competition Soon

Did you know? Botox® has been a mainstay in non-surgical facial enhancement for over a decade, and has proven safe and effective. Every year we find more ways to use it (for example, to raise the corners of a downturned mouth, or soften the lines around the mouth). In the next one to seven years, expect to see up to three Botox®-like compounds approved for use in the United States.

The first compound likely to appear is Reloxin®, available now in Europe under the name Dysport, made by the Medicis Corporation. Also in the pipeline are Purtox®, by the Mentor company, and Xeomin®, by the Merz Corporation. It is expected that differences between the compounds will be relatively small. It will be interesting to note whether or not competition will result in a decrease in price.

Did you also know? Ophthalmologists were the first to use Botox both therapeutically and cosmetically. It was first used to weaken the muscles in certain cross-eyed conditions as well as to weaken the muscles in a condition called blepharospasm, where affected patients involuntarily squeeze their eyes shut.

I first used Botox® 15 years ago for patients with blepharospasm. My staff members would ask me to treat their wrinkles with the leftover medicine. Quickly they told my patients, and now it is a large and rewarding part of my practice!

Self-adjusting eyeglasses?

Did you know? Joshua Silver, a British physicist, aims to make eyeglasses more readily available for poor people around the world. He has developed eyeglasses which can be adjusted by inflating or deflating a fluid filled lens. When the lens is properly adjusted, the adjusting syringe is removed and the glasses are ready to wear.

His glasses have been recently publicized in the Washington Post and on NPR. He states that the glasses cost $19 each now, but he hopes that when production is scaled up the cost will decrease to $1 each. 

The glasses are limited in that they do not correct for astigmatism and at this point correct from -6 to +6 diopters. Also, they would not come as bifocals, I imagine.

I wish Mr. Silver all the success. As someone who regularly works in third-world eye clinics, I know that this is something which could be a great benefit to the truly underserved.

I am sure Mr. Silver has investigated and been approached by all types of distribution possibilities. I hope that various for-profit models are seriously looked into, since businesses using very small margins and very high volumes have been used to gain widespread distribution of everything from shampoo to cell-phones in third-world countries. 

Did you also know? India has developed a model of private and charity eye care combined with low-cost intraocular lens manufacturing to bring cataract surgery to the poor. 

Testing Your Color Vision

Did you know? There is an online resource which enables you to test your color vision.  The X-Rite company, which manufactures devices which insure color standardization between computer monitors, provides a color test on their website. The test is called the 100-hue test, and involves arranging tiles in order of their hue. It's rather challenging, are you up to it? (the test requires registration). Find the test here.

Did you also know? Except when suspecting optic nerve disease, ophthalmologists rarely test color vision, and rarely so extensively as with the 100 hue test.

Critical Thinking

Brian Dunning is the host of one of my favorite podcasts, called Skeptoid.

Since not everyone listens to podcasts, Brian produced a video which encapsulates what you need to know to think critically. This ability is crucial to evaluating medical and nutritional claims, as well as claims you hear everyday in the media or on the internet.

My blog frequently features possible new treatments for eye diseases. These claims must be evaluated critically. Brian's video is a good place to begin. Especially valuable is his concise description of how a proper clinical trial is designed and implemented.

Happy Birthday, Joaquin Rodrigo! (1901-1999)

Did you know? Famed Spanish composer Joaquin Rodrigo was born on this day in 1901. He is best known for his guitar concertos, which helped introduce the guitar into the classical repertory. 

Rodrigo was blinded at age 3 from diphtheria, according to his biography. Diphtheria, while exceeding rare today, was common before the diphtheria vaccine was invented. Diphtheria causes a thick membrane to form over the mucous membranes, typically in the airways, which can cause death. It also can cause scarring of the conjunctiva (the membrane over the white part of the eye) and ulceration of the cornea. 

Did you also know? Beginning in 1939 (until ?) Rodrigo was the head of the artistic section of ONCE, the Spanish foundation for the blind. ONCE remains today a powerful global force helping the blind integrate into society.

 

image courtesy Wikimedia Commons

Izon® Eyeglasses, by Ophthonix

Did you know? For a number of years, San Diego–based Ophthonix has produced customized eyeglasses as well as an aberrometer/autorefractor to measure the eye's wavefront characteristics and refraction. It is only recently, however, that a large-scale, well-designed, rigorous, double-masked study has been presented to show the effectiveness of these eyeglasses as well as the process by which they are made.

This paper is available on their website, here. It's not light reading, but would be of interest to an ophthalmologist, optometrist, or optician. It's small print, too, so I recommend downloading the pdf file and using your pdf viewer to enlarge the text.

The study was performed at the prestigious University of Illinois Eye and Ear Infirmary, and published in the Review of Optometry, October 2008 (not a peer-reviewed publication). 

The study consisted of two phases. The first phase tested 83 subjects with their old glasses, new glasses prescribed by a regular refraction, and glasses made by Ophthonix (wavefront-guided iZon® lenses). Subjects wore each of the new glasses for two weeks, and neither subject nor experimenter knew which lenses were being tested.

A battery of visual function tests was administered. The iZon lenses performed the best on seven of nine parameters, and the difference was statistically significant on four of them.

A second phase consisted of testing 52 subjects. Each was given four sets of lenses: lenses made with a traditional refraction made elsewhere, a traditional refraction made at the Ophthonix lab, glasses made with a refraction from the Ophthonix autorefraction, and glasses made with the Ophthonix autorefraction with wavefront-guidance and their proprietary 3-layer lenses.

The results of the second phase can be summarized by "there is an ordered progression of visual benefits derived from the components of the lenses... the best overall visual performance was gained by coupling Z-view® refraction with a 3-layer lens iZon® lens design."

It is notable that many of the visual tests in which the iZon® lenses excelled were ones which have real-world consequences, such as low-contrast situations (like driving at night), glare situations (like driving into headlights or playing golf on a sunny day), and tests called the Environmental Visual Acuity Test, which measured how much farther away subjects could read signs they encountered (the iZon® lenses provided a 20% improvement compared to a conventional lens), and the Low-Luminance Acuity Test (viewing dark letters against a dark background-- like driving on a dark road at night--the iZon® lenses provided a 20% improvement vs. all other lenses.)

The study is also notable for it provides the first somewhat clear description of just what occurs in the production of iZon® lenses. Rather than correcting for wavefront aberrations, (which custom-Lasik surgery attempts), the iZon® lenses are said to optimize vision in this way:

iZon®Lens Structure (3-Layer) 

The wavefront-guided iZon®Lens is a unique design, with a three 

layer structure. The mid-layer iZonikTMmaterial is a photo-polymer that 

is sandwiched between separate back and front lenses. All three lay- 

ers are 1.6 index material. The correction for the iZon®Lens is derived 

from all 2nd to 6th order aberrations of the eye as measured by the 

Z-View®Aberrometer. The aberrations are analyzed and manipulated 

by a proprietary algorithm—the second of two used in the iZon®Lens 

process—to determine the best sphere-cylindrical fit for the back 

surface. The iZon®Lens is wavefront-guided, as opposed to wave- 

front-corrected. Wavefront-guided refers to the use of wavefront tech- 

nology to incorporate all 2nd to 6th order aberrations in determining the 

best sphere-cylindrical fit, as opposed to wavefront-corrected that 

implies correcting individual aberrations. By utilizing a wavefront- 

guided approach,  the iZon®Lens is optimized and unaffected by gaze 

angle shifts that could result with the programming required in a 

wavefront-corrected design. 

The key point of this paragraph is that "the aberrations are analyzed and manipulated by a proprietary algorithm to determine the best sphere-cylindrical fit for the back surface."  

It's not clear to me if the front surface of the lens or the thin iZonik (tm) layer sandwiched between have refractive properties, but this does indicate that the higher-order aberrations are not being precisely corrected for, but rather are being used to give a better sphere/cylinder correction. 

It apparently works (for those 65% of the population who are candidates for the lenses) to provide crisper "high-definition" vision with gains in many visual measurements.

One finding lacking in this study was a subjective evaluation of the lenses by the subjects. Previous studies showed a very large preference for the iZon® lenses vs. conventional lenses.

As a final note, I have had a pair of iZon® glasses for over a year. My impression is that they provide exceptionally crisp vision, but I don't have a conventional pair made at the same time to compare them to.

I can say that the autorefraction obtained of my eyes by the Ophthonix Z-View® autorefractor/aberrometer is the most accurate autorefraction I have ever had. It wasn't necessary to change a thing! 

Also of note is that I have a small financial interest in the Ophthonix corporation.

Did you also know? Other companies are using other technologies to customize eyeglass lenses. One company promises "changeable-focus" lenses with no moving parts. Time will tell if this becomes a reality.

Plugging away at glaucoma!

Did you know? Researchers are investigating a novel method to deliver medications to the eye. A study sponsored by the QLT Corporation placed medication for glaucoma in a small plug, inserted into the lower punctum of the eye. You have probably noticed these tiny openings in your eyelids which drain tears from the eyes into the nose. By placing a plug in the punctum, the drug within slowly dissipates. Some of the drug travels back upstream through the tears and into the eye. In this case, the drug, Xalatan, lowered the eye pressure for twelve weeks, and nearly as much as when given as an eyedrop. The study was not perfect (lots of patients dropped out) but it certainly tells us that this is a promising area which could lead to use for many ocular conditions.

Did you also know?  Many studies have shown that up to half of patients do not take their prescribed eyedrops for glaucoma. A drug-impregnated punctal plug could be a huge benefit for these patients!

(image courtesy Diogo Melo Rocha, creative commons)