Contact Lenses To Treat Eye Allergies

July 5, 2011 By Leave a Comment

Acuvue K The Contact Lenses For Itchy Eyes


Contact lenses are about to enter a new realm as drug delivery devices.  While a number of applications are expected, Acuvue may be the first off the block with an antihistamine releasing lens. In 2007 Vistakon,  the manufacturer of the Acuvue lens family, sponsored a clinical study of healthy patients wearing a lenses with ketotifen.  Eye doctors followed over 300 patients and evaluated for any complications over a period of 12 weeks while they wore the lenses. On June 23 2011 the final comments were added.

Acuvue K-Lens For Eye Allergies Appears to Be A Safe Contact Lens

There were two serious problems in people wearing the Acuvue K contact lenses. One patient had to be hospitalized for gastrointestinal problems and another for a nose fracture from a fall. I believe it is unlikely these were related to the contact lenses but time will tell.  Statistical analysis of the results has not been made public but it appears that every marker of eye inflammation measured was not significantly changed by the contact lenses.  Ketotifen is the same anti-allergy drug found in the over the counter drops Zaditor and Alaway.

Itchy Red Eyes Are Only The Beginning!

Eye allergies can  diminish the quality of life when they are severe and constant. All eye drops share the common problems of accurate and prolonged dosing over time. A single drop may be blinked out and/or the amount your eye receives may last for a very short duration. By adding drugs to contact lenses eye doctors should be able to assure a steady dosage over long periods.

Many eye diseases may show much higher response rates when they are delivered in contact lenses. Glaucoma, eye infections, and uveitis (inflammation inside the eye) are probably going to be treated with contact lenses in the near future.

Someday you may even be told to take two contact lenses and call in the morning!


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Optic Nerve-The Remarkable Eye

June 30, 2011 By Leave a Comment

Optic Nerve In Eye

Did you ever wonder what the nerve inside your eye looks like?

Eye Disc Nerve

Optic Nerve As It Appears To Your Optometrist

You can see a small circular yellow image in the middle of the streak of light in this picture to the left. That is where the optic nerve is entering the eye. Before it enters the eye it is covered with myelin. Myelin acts like the insulation on a wire and speeds the transmission of the signals from the photo-sensitive cells inside the eye to the back of the brain. Myelin is fairly opaque so it stops as the nerve fibers travel to the interior of the eye. The nerves are arranged in front of the rods and cones and would interfere with vision if they maintained the opacity.

 

The optic nerve is about 1.5 mm in diameter and carries approximately 1.2 million separate fibers. Imagine trying to connect a wire with over a million strands. The nerve itself creates a small circular blind spot where it penetrates the eye. While your eye doctor can measure this with a visual field testing instrument, the brain completely filters it out. That is fortunate since otherwise everyone would constantly see a dark hole in their vision.

Your Optometrist Can Detect Many Health Problems From Your Eye Exam

The nerve becomes elevated and swollen in some eye diseases and with some tumors of the brain. This can be seen on an eye examination when eyes are dilated. There are blood vessels that accompany the nerve into the eye. The blood vessels provide a view of the health of the entire body. Health problems like high blood pressure create changes in the blood vessels of the eyes that can be detected in vision examinations.

Eyes Are Remarkable!

It is remarkable when you connect a small nerve under 2 millimeters in size to the incredibly extensive world of vision and perceptions that we inhabit.

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Cysts Over The Eye Whites

June 27, 2011 By Leave a Comment

Bumps And Cysts On The White Of The Eyes Can Be Scary


Small transparent bumps over the white part of the eye that appear suddenly are usually diagnosed as inclusion cysts or conjunctival lymphangiectasia. Fortunately neither one is nearly as bad as it sounds.

Conjunctival Inclusion Cyst

Cysts on White Of Eyes

Two Common Causes For Cysts On The Eyes

Inclusion cysts are small fluid filled cysts from a thin enclosure of conjunctival epithelium. Epithelium is the surface tissue on the eye, analogous to the epidermis that forms the superficial layer of our skin. Sometimes inclusion cysts form after various types of eye surgery (strabismus for crossed eyes, cataract surgery, vitrectomies, ptosis surgery for drooping eyelids, and scleral buckles for retinal detachments). On occasion the fluid may be a little turgid or cloudy towards the bottom of the cyst and create a more difficult diagnosis. Larger inclusion cysts may also create some discomfort when they rub against the eyelids.


Conjunctival lymphangiectasia are the second common cause for transparent cysts on the surface of the eye. Unlike an inclusion cyst, these often appear as multiple small bumps on the surface of the eyes. The eye has a lymph system that help drain off the fluid that forms between cells. In contrast to the small capillary blood vessels (and inclusion cysts), it is not very complex. The cells that form it are loosely held together without an underlying membrane, and the valves that regulate the flow through it have very little structured control. It is not altogether surprising that sometimes the lymph flow through the conjunctiva gets out of kilter and forms these little cyst like structures.


Most of the time we don’t know the exact cause of cysts on the conjunctiva. Inclusion cysts are a result of some epithelial cells getting separated off and isolated. This can be congenital (occurring at birth) or develop later in life. Eye surgery can promote this condition by displacing remnants of epithelial cells. Any type of chronic eye inflammation may also induce the normal epithelial cells to abnormally reproduce and tend to form cysts. This may be the reason why conjunctival cysts are sometimes associated with eye allergies. A condition referred top as Steven’s Johnson Syndrome also can result in inclusion cysts. Conjunctival lymphangiectasia represents some type of dysfunction of the lymph drainage system of the conjunctiva. Where things go wrong is mostly speculation at this time.

See Your Eye Doctor For Any New Bumps On Your Eyes!

In our Fort Collins office, the majority of bumps we see are pinguecula. Pinguecula may appear similar to cysts but they are solid and not filled with fluid. Other more serious eye problems such as non pigmented melanomas must be ruled out when bumps appear on the eyes.  Don’t take chances with your eyes, see your optometrist right away for any new bumps or lumps on the surface of your eyes!

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June 27, 2011 By Leave a Comment

Bumps On The White Part Of The Eyes Can Be Scary

Small transparent bumps over the white part of the eye that appear suddenly are usually diagnosed as inclusion cysts or  Conjunctival lymphangiectasia. Fortunately neither one is nearly as bad as it sounds.
Conjunctival lymphangiectasia

Fluid Cyst On Conjunctiva Of Eye

Two Common Causes For Cysts On The Eyes

Inclusion cysts are small fluid filled cysts from a thin enclosure of conjunctival epithelium. Epithelium is the surface tissue on the eye, analogous to the epidermis that forms the superficial layer of our skin. Sometimes inclusion cysts form after various types of eye surgery (strabismus for crossed eyes, cataract surgery, vitrectomy, ptosis surgery for drooping eyelids, and scleral buckles for retinal detachments). On occasion the fluid may be a little turgid or cloudy towards the bottom of an inclusion cyst and create a more difficult diagnosis. Inclusion cysts may also cause discomfort when larger as they rub against the eyelids.

Conjunctival lymphangiectasia are the second common cause for transparent cysts on the surface of the eye. Unlike an inclusion cyst, these often appear as multiple small bumps on the surface of the eyes. The eye has a lymph system that help drain the fluid that forms between cells. Unlike the small capillary blood vessels (and inclusion cysts), it is not very complex. The cells that form it are loosely held together without an underlying membrane, and the valves that regulate the flow through it have very little structured control. It is not altogether surprising that sometimes the lymph flow through the conjunctiva gets out of kilter and forms these little cyst like structures.


Most of the time we don’t know the exact cause of cysts on the conjunctiva. Inclusion cysts are a result of some epithelial cells getting separated off and isolated. This can be congenital (occurring at birth) or arise later in life. Eye surgery can induce this condition by displacing remnants of epithelial cells. Any type of chronic eye inflammation may also promote the normal epithelial cells to abnormally reproduce with a tendency to form cysts. This may be the reason why conjunctival cysts are sometimes associated with eye allergies. A condition referred to as Steven’s Johnson Syndrome also can result in inclusion cysts. Conjunctival lymphangiectasia represents some type of dysfunction of the lymph drainage system of the conjunctiva. Where things go wrong is mostly speculation at this time.


See Your Eye Doctor For Any New Bumps On Your Eyes

In our Fort Collins office, the majority of bumps we see are pinguecula. Pinguecula also form bumps over the scleral tissue but they are not fluid filled like cysts. Other more serious eye problems such as non pigmented melanomas must be ruled out when bumps appear on the eyes.  Don’t take chances with your eyes, see your optometrist right away for any new bumps or lumps on the surface of your eyes!

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Dark Spots On Whites of Eyes

June 23, 2011 By 9 Comments
Dark Color Spots On Eyes

"Birth Marks On Eyes"

Ocular Melanosis-Dark Spots on The

White of The Eyes

 

Dark spots that appear over the white areas of the eyes can be usually benign growths of the pigment producing cells known as melanocytes. There are three different type of benign growths:

  1. Freckles (congenital epithelial melanosis)- these are small area of brown pigment close to the iris (colored tissue on the eye).  They are present at birth.
  2. Benign melanosis-small pigmented spots similar to freckles but appearing at middle age
  3. Ocular melanosis

Ocular Melanosis (Technically Congenital Ocular Melanocytosis) presents a picture similar to what is seen in the left image. There are rather dramatic large areas of gray and almost blue discoloration seen on both eyes.

You Should Have An Eye Doctor Evaluate Any Dark Spots On Your Eyes On Your Child’s Eyes

The classification of pigmented spots over the white part of the eyes is somewhat confusing. The sclera is traditionally thought of as the white of the eye. Is is covered by a thin layer known as the episclera. On top of this is the outermost layer, a transparent covering  known as the conjunctiva (which becomes inflamed during attacks of conjunctivitis or pinkeye). Pigmented spots can occur in one or all of these different layers.

Melanocytes are the cells that contain melanin, the pigment that darkens the area. There can be an increase in the number of melanocytes or in the  amount of melanin. The pigmentation changes seen in this eye were present at birth and involve increase numbers of melanocytes in the episclera and possibly the sclera. While there is some disagreement most researchers beleive there is a rare increase for the risk for a melanoma developing on the eye. About 10% of people with ocular melanocytosis will also develop a secondary case of glaucoma. If a patch of pigment manifest on the skin surrounding the eyes. it is called Nevus of Ota.  When a  Routine annual eye examinations are generally the recommended care if no changes are seen.

This may also be referred to as congenital ocular melanocytosis, blue nevus of the sclera, birth marks on the eye, and freckles on the eye. It is not the same as a dis-colorization that develops after birth. This isusually noted as Primary Acquired Melanosis and is localized in the conjunctival tiusse layers.

Fortunately this type of dark spot on the eyes is not a sight threatening condition in the majority of cases



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Fuch’s Corneal Dystrophy Eye Problems

May 23, 2011 By Leave a Comment

Fuch’s dystrophy is an eye condition effecting the clear corneal tissue covering the colored part of the eye. The cornea is an incredible tissue measuring only ½ mm thick with layers of collagen aligned precisely to allow for transparency. It is separated into five regions, the posterior most being the layer of endothelial cells. The endothelial cells function to keep the cornea from being inundated with water. Accumulation of water results in swelling and haziness that blurs vision. Normally the cornea is about 70% water, exceeding the fluid content of most contact lenses. If the endothelial cells start to lose their capacity to pump water back out of the cornea, the fluid content starts to rise above 70% and the cornea begins swelling. Above 4% swelling the aftermath is haze and fogging of vision. In a healthy eye during sleep the eyelid serves as a barrier to oxygen flow and the cornea swells 3-4% overnight. The criteria for oxygen permeability of overnight wear contact lenses is to stay close  to the 3-4% swelling and avoid the complications that accompany the accumulation of water in the cornea. 

Cornea Blisters Fuch's

 

In Fuch’s Dystrophy The Cornea Determines How Well You See. The endothelium lines the deepest surface of the cornea and normally new cells do not grow to replace damaged or aging cells. This makes the endothelial cells vitality critical for clear vision. Age reduces the number of cells present as does most types of eye surgery. In Fuch’s, the endothelial cells reach a critical point where they have decreased to an inadequate number and/or no longer work well enough to keep the aqueous fluid inside the eye from overwhelming the corneal tissue. Typically this happens at age 50+ and seems to be much more frequent in women. There is a genetic component. The initial damage starts from growth like bumps secreted by the endothelium called guttata. These abnormal accumulations of tissue distress Descemet’s membrane and the endothelial cells. Eventually the effect spreads to the surface of the eye where blisters and fluid accumulation result in poor vision and discomfort.

Early Treatment of Fuch’s by Eye Doctors includes hypertonic eye drops that draw the fluid out of the cornea. Mildly warm air blowing on the cornea at arms length from an air dryer has also been used to dry out the cornea. In the advanced stages of Fuch’s Dystrophy corneal surgery may be required to restore vision. In the past, the cornea was removed to a deep level and a donor circle of cornea was sutured back in place. Today, new procedures that are much less invasive are becoming widespread. Descemet’s stripping with endothelial keratoplasty (DSEK) has become very well accepted and has very good results. Descemet Membrane Endothelial Keratoplasy (DMEK) is another new procedure that trnasplants Descemt’s Membrane and the endothelium. These new procedures are improving outcomes in patients with Fuch’s and giving new hope for tomorrows vision.

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Eye Floater After Vitreous Detachment

May 17, 2011 By 2 Comments

Vitreous Eye Floater

 


Follow The Small Dark Floater As It Moves Inside The Eye

Most people will have a vitreous detachment by age 65. The vitreous fluid inside the eye loses its firm jell type structure with age and becomes more like water. The vitreous is covered by a membrane like structure on the outer edges. This is attached to the retina around the optic nerve. As the fluid liquefies it pulls away from this attached area. The detached membrane often leaves a circular ring like floater commonly referred to as a Weiss Ring. Like most floaters, this one moves as the eye moves then begins a slower drift back towards its original position. That creates the illusion of something in your peripheral vision that always moves one step away as you turn your eyes to try and see what is there.

Vitreous Floaters Can Be Related To Retinal Detachments

Floaters and spots in your vision can be related to retinal detachments. Call your optometrist immediately  if you have an onset of floaters. Your eye doctor can help decide if this is an eye emergency that needs urgent care. Fortunately most of the time vitreous detachments and a Weiss Ring do not result in a retina detaching. As a plus, the floaters also tend to settle down to the bottom of the fluid and become much less noticeable over several months time.



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Pupil Dilation And Drug Abuse

April 26, 2011 By Leave a Comment

Pupil Dilation And Drug Abuse

Heroin and opioid drugs like morphine and Vicodin cause the pupil of the eyes to constrict. One of the signs of substance abuse with this category of  drugs is small pinpoint pupils. The lack of dilation is a possible warning of a serious addiction problem. According to a study in the  British Journal of Ophthalmology (1995) there is habituation of the pupils to the drugs. The pupil does adapt and dilation occurs more readily over time.

Dilated Eye

Large Pupil Dilation

Why Don’t Pupils Dilate After Time?

If drug tolerance builds up over time the eyes should return to a more dilated state. Since that does not seem to be the case what is going on? The answer is simple-increasing amounts of narcotics are used to achieve the same level of euphoria by most addicts. This keep the pupils in a constricted state even though they are habituated to the prior dosage levels.

Can Your Eye Doctor Tell If You Have Been Abusing Drugs?

The short answer is probably not.  Pupil size varies greatly between individuals and with age becomes smaller. Extremely small pupils in a young person with other signs of altered mental status can be a strong indicator. Naloxone is a drug used to treat overdoses. If applied in a drop to the eye it produces dilation in people with drug addiction. It is not something an optometrist would use in a routine eye exam. Normal eye drops to dilate the pupils won’t work as well in cases of dependency. If you are concerned about a child or friend having a potential drug problem observing their pupil size is not a bad idea. Tiny pupils are hard to miss in a teen. If they are present after the age of 40+ it is not as significant since the pupils does get smaller as we age. One other thing to look for is a sluggish pupil response where the eyes take longer than normal to dilate after the lighting lessens, or after a teens eyes shift in focus from near to distance.

When you notice these changes accompanying behavior alterations take some action before its too late. Then there is the eye rolling phenomenon. All I can say is good luck with that one!



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Macular Degeneration Treatment Aptamers

April 13, 2011 By Leave a Comment

Macular Degeneration Treatment

Current treatment of macular degeneration involves the use of anti-vascular endothelial growth factor drugs (VEGF). Vascular endothelial growth factors are proteins that support the normal development of blood vessels before birth. They also stimulate blood vessel growth after injuries and compromised circulation problems. The growth of unwanted blood vessels in the retina of the eye creates the vision threating issues of macular degeneration. Anti-VEGF slows this progression of vision loss.

Drug Therapy For Macular Degeneration

Aptamers are molucues fabricated to bind securely to a target. Macugen (pegaptanib) was approved in 2004 for the treatment of macular degeneration and was the first aptamer used in the treatment of any human disease. It is both an anti-vascular endothelial growth factor and a aptamer. Macugen binds to the protein responsible for blood vessel proliferation in the wet form of macular degeneration and inhibits new blood vessel formation. Eye doctors have mostly switched to using Avastin and Lucentis, which typically produce a small improvement in vision. Macugen slows progression of macular degneration but has not been shown to enhance eyesight. While Avastin and Lucentis are not aptamers, a clinical study is underway to test the addition of an aptamer to Lucentis injections.

Individualized Treatment Of Macular Degeneration

Aptamers should have a bright future in the treatment of eye diseases. Their precise targeting capacity in combination with nanotechology should allow for very individualized treatment eye doctors can only imagine today.
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Acuvue Advance Plus or Minus

April 12, 2011 By 7 Comments

New Acuvue Contact Lens- Or Is It?

Vistakon announced late last year the introduction of the Acuvue Advance Plus contact lens. Plus means they have made it better right? Not quite so fast. According to Vistakon’s website, the Acuvue Advance Plus utilizes ULTRA-CLEAN™ Technology that helps resist the buildup of deposits on the lens surface.

A New Improved Acuvue Contact Lens Material?

Gas Permeable Contact Lens

Contact Lens On Eye


Maybe-but there is little evidence that it is. The plus part of the Acuvue Advance contact lens seems to be a change in “equipment qualification”. Equipment qualification is a global term the Food and Drug Administration uses to make sure that equipment used in manufacturing and testing of a medical device does what it is supposed to do. Apparently some of the equipment used in production of the Acuvue Advance contact lens was updated (or at least changed). The Acuvue Advance Plus contact lens is manufactured with a process referred to as “Ultra-Clean™ Technology”.  What that mean is not clear. It is an unregistered trademark that translates to a marketing exclusivity privilege. Maybe your carpet will be magically cleaned the next time you drop a contact lens!

Whats Different About the Acuvue Advanced Plus?

Beyond the “Ultra-Clean™ Technology” not so much. The lens is still made from the same polymer, Galyficon A with 47% water. The contact lens polymer is still stated to include Hydraclear™ technology to improve comfort.

While I have seen the Acuvue Oasys contact lens material help some patients with dry eyes in Fort Collins, I do not believe the Acuvue  Advance Plus will be a significant improvement for optometrists specializing in contact lenses in Colorado (or anywhere for that matter). If you are currently wearing the Acuvue Advance at some point it is going to be discontinued as the contact lens manufacturer transitions to the Plus version. I don’t think you will notice either way. There was an F.D.A. study prior to qualification but no results have been posted to date. They must have been OK. Here is to a new an improved 2011!


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