Eyedolatry

Previewing Fall/Winter 2015 Runway Eyewear

2015 eyewear fashion trends 7:00 AM

Share |

New Study Suggests Oral Azitrhomycin Superior To Doxycycline for Meibomian Gland Dysfunction

Share |

Troubleshooting Your Orthokeratology Fit

basic design orthoK contact lenses 7:00 AM

The goal of orthokeratology is to correct vision overnight by reshaping the cornea with enough pressure to have lasting clarity the next day. Besides having the correct amount of treatment pressure to negate your prescription, the lens has to be well centered on the eye all night long, and still allow appropriate tear exchange underneath the edge of the contact lens to allow for good corneal health. If the lens edge is too tight or too flat, the result is reduced comfort as well as a higher risk for mechanical damage to the eye like superficial punctate keratitis, inflammation, and even corneal abrasion. If you think of it in the most simplistic terms, your orthoK fit needs to achieve these 3 things: Correction, Centration, and Comfort. Here's how to acheive your three keys to success:

1) Patient Selection

Selecting the right base curve is your key to correcting your patient's prescription. Popular lenses like Paragon CRT have a nomogram tool to help calculate your proper base curve dimension based on the patient's spherical Rx and their flat K reading. The best bet for success also lies in patient selection. Orthokeratology won't work on all prescriptions, so know your best patient candidate to ensure the highest chance for success before you get started.

The ideal orthokeratology patient has up to -4.00D myopic prescription and no more than -1.00D of corneal astigmatism. Their K values will ideal be between 42 and 45. It is possible to do orthokeratology on patients outside of this range, but the lens selection will be more difficult, and there is a good chance the patient won't have perfectly corrected vision the next day.

Difficult patients for orthokeratology include: against the rule astigmatism (the lens tends to decenter!), very flat corneas (post-LASIK patients would be very difficult), and patients whose astigmatism is greater than their spherical prescription. Also, patients who have lenticular astigmatism will not be expected to have that improve with orthokeratology, so make sure you check your Rx with your K's to verify their astigmatism is corneal.

2) Breaking Down the Ideal Lens Fit:

The ideal lens is well centered on the eye with a central treatment zone of about 3-4 mm diameter. You would want alignment staining in the return zone area 360 degrees around, with no bubbles. And on the edge of the lens you would ideally want 1-2 mm of clearance to prevent lens seal off. Read this post for more details and a deeper explanation of each zone.

3) Troubleshooting Fit Issues -- change one of these parameters at a time. Paragon recommends starting with option #1 in the lists provided when changing fit, and then if the issue persists, changing option #2 next.

An inferiorly decentered lens. Read below to learn how to fix this! via

Poor Centration:

Lens Decenters Left, Right, or Superior?

1. Increase Return Zone Depth by 25 microns
2. Increase Landing Zone Angle by 1 degree
3. Go to larger diameter lens

Lens Decenters Inferior?

1. Decrease Landing Zone Angle by 1 degree
2. Decrease Return Zone Depth by 25 microns

Inadequate Central Treatment Zone:

1. Decrease Landing Zone Angle by 1 degree
2. Decrease Return Zone Depth by 25 microns
NOTE: If you aren't getting a good treatment zone, double check your over refraction. Ideally over top of the contact lens you should get a plano to +0.50 over refraction with no cyl. If there is cyl in your over-refraction over the contact lens, then it is untreatable. If you have > +0.50 over refraction, then Decrease the Base Curve by 0.1 mm for every 0.50 D of correction you need to reverse.

Fitting someone with more than -5.00D of myopia? It can be done, but the treatment will take longer, and there is a high chance they may have residual myopia even with the best fit lens. Paragon recommends increasing your Return Zone Depth by 25 microns if you need more myopic treatment, and then have the patient wear the lens for 1-2 weeks and reassess before making further changes.

3) When to Follow-Up

Initial Dispense: Dispense the lens, and have patient wear it overnight and return to clinic wearing the lens the next morning.

Assess fit and centration with NaFl staining

A 3-D topography of an eye post-orthoK lens wear. The central cornea is
depressed (the treated zone) and the mid peripheral cornea will be
elevated where the corneal tissue has been displaced. via

Over-refract over the lens (you want plano to +0.50)
Remove the lens and perform topography to assess treatment zone pattern
Refract to see the amount of treatment achieved

On average, expect about 2.00D of treatment on night one with a well centered orthoK lens. The patient may need to take home soft contact lenses at this visit if they have a higher prescription to correct,

One Week: Typically we have the patient come in after school, not wearing the lenses. Make sure they bring the contact lenses with them to the visit!

Perform topography and refraction (you are wanting close to full correction at this point unless they were a higher Rx in which case they may need a second week to achieve full correction)
Insert lens and assess fit and over-refraction

One Month: Same as 1 week visit, just following up to ensure continued comfort and performance

Six Months: Typically we are fitting these lenses on growing children, so if they were known to have a high speed of myopia development before their orthoK fit it isn't a bad idea to recheck in 6 months to make sure things are under control. Especially in brand new wearers the 6 month follow-up can help keep things on the right path and instill the concept that the eye is changing and we may need to change the lenses to keep up. The hope is that we have stabilized the eye's myopic growth rate, and the best way to achieve that success is to make sure the lens is properly fitting and fully correcting the issue.

One Year: Studies recommend for best chance of myopia control, the lenses should be changed yearly in growing children. The lenses themselves can warp with time, like any RGP, causing less controlled treatment of myopia and a greater chance of myopic slippage.

Share |

Orthokeratology: The Basic Design

base curve ortho K 7:00 AM

Orthokeratology contact lenses reshape the cornea overnight to provide clear vision during the day without the need for contact lenses or glasses during those daytime hours. These specialty contact lenses can be great for children, athletes, or those with jobs or lifestyles that make glasses or contact lens wear very difficult. As a practitioner, prescribing these contact lenses involves much more technical skill than the average contact lens, and adjusting the lens for better vision and fit requires a working knowledge of different parts of the design that are completely unique to orthokeratology lenses. These lenses employ a large reverse curve change, where the central part of the lens bears down on the cornea while the mid peripheral region of the lens vaults back up to align the contact lens properly on the eye. Today's post breaks down the basic design of orthokeratology contact lenses, and to help determine what parameters need to be changed to achieve that best fit for maximum lens performance and next day clarity!

A Perfect Fit with Paragon CRT lenses via

Fitting orthokeratology contact lenses requires assessment of 3 zones of the contact lens:

1) Base Curve

The central area of the contact lens (6mm in size in the popular Paragon CRT lens design) is the base curve region. This area is the main pressure point for vision correction -- specifically calculated to negate the patient's myopic prescription. The only reason to change this curve is to get more vision correction -- don't change this to change the fit of the contact lens! With Paragon CRT lenses, the appropriate base curve will be selected by the patient's spherical equivalent prescription and their flat K using a nomogram, so very little calculation will be needed by you in initial lens selection. If you need more prescription correction later on, you can flatten the base curve to achieve more correction.

Increasing the Base Curve will flatten the contact lens (or create more treatment).

Increase the Base Curve (flatten) by 0.1 mm = 0.50D more myopic treatment

2) Return Zone or Reverse Curve

The Return Zone area is just outside of the central base curve region where the contact lens lifts back up off of the cornea. In the Paragon design it is ideally about 1 mm in size. The Return Zone is measured in microns of sagittal depth (much like when you fit scleral contact lenses!) so you are measuring the amount of lift off of vault away from the cornea. The Return Zone is essential to aligning the contact lens for centration, so this is an area that you may need to adjust to achieve best fit!

Higher Return Zone Depth = More Lift Off of Cornea

Typically change this by 25 micron units to achieve visible results

The key to Return Zone measurements is that you want alignment fit with the cornea underneath. If there are bubbles in this area, you have too much sag depth and you need to lower the Return Zone. If you don't have a well defined central pressure zone, you may need to increase the Return Zone to get more treatment and better alignment.

3) Landing Zone or Alignment Curve

The very edge of the contact lens is the landing zone, allowing the lens to fit comfortably on the cornea. The lower the landing zone angle, the more edge lift you will achieve as the edge of the lens lifts up and away from the cornea. Ideally you want 1-2 mm of tear film between the edge of the contact lens and the cornea. If you have too little tear film underneath, the edge would be too tight and will be increasingly uncomfortable with wear, not to mention that underneath your closed eyelid the contact lens may not be centered and you would awake with poor vision the next day. If the edge lift is excessive, again comfort will be a major issue as you blink, and centration will also be an issue.

Lower the Landing Zone Angle by 1 Degree to Increase Edge Lift

Increase the Landing Zone Angle by 1 Degree to Decrease Edge Lift

Here's another tricky part, if you change the Landing Zone angle, you will also change the Return Zone depth: Decreasing the Landing Zone by 1 degree will Decrease the Return Zone sag depth by around 15 microns. Typically if you want to make changes to contact lens alignment in small increments, you would start by changing the Landing Zone before you change the Return Zone. That's because changing this area will impact your Return Zone anyway.

Stay Tuned for the next post in this series: trouble shooting orthokeratology fits.

Share |

Bruckner Testing

abnormal bruckner test 7:00 AM

Wouldn’t it be great if there was a quick and easy way to check for the potential for reduced vision in an eye without having to rely on a child to read letters on a chart? Think about all those times that you need objective results – when a child is too shy, or just not wanting to cooperate, or even in patients that cannot communicate to tell you what they see. Luckily optometrists have methods to get around the limits of testing very young, precocious, shy, or nonverbal patients. The Bruckner Test is one such method that helps unlock your child’s visual world without them having to do anything more difficult that look at a light.

An abnormal Bruckner test shows unequal light reflexes between the eyes. The lighter/brighter reflex (right) is the eye with the potential amblyopia. via

What it Tells You: The Bruckner Test uses the light reflex from the retinal tissue in the back of the eye to assess visual ability. If a child has equal acuity in each eye, we would expect the light reflex coming from the back of the eye to be equal. But if one eye shows a much stronger (or “brighter”) reflex than the other, the doctor knows there is a risk for amblyopia (or lazy eye as it is often called in layman’s terms).

All you need! via

Equipment You Need: All you need for a Bruckner Test is a direct ophthalmoscope, making it a quick and simple evaluation that can be done both in an office and at off-site visual screenings.

How To Perfom:

Stand 1 meter or about 3 feet away from the patient.
Tell the patient to look at your light (typically they will do this anyway, but you can turn off the room lights to minimize distraction if needed)
Compare the brightness and color of the light reflex between the right and left eyes.

Interpretation:

The macula is the area of the eye dedicated to best fine detailed, central vision. To achieve best visual acuity, we need to use our macular retinal photoreceptors when we look directly at any visual target. If the patient is using the macula to focus, we would expect a deep red reflex to appear in our direct ophthalmascope. This is because the macula is our area of densest photoreceptor presence and thus the darkest pigmented point in the retina. If there is an inequality of the color and brightness of the light reflex, the eye with the lighter and brighter reflex is the eye that is potentially amblyopic. If you recall your student days: Bright is Bad in Bruckner’s was a common memorization tool. The brighter reflex results because the eye is either not using the macula for fixation, or not accurately focusing light on to the macula. Because the lighter reflex could be from several causes, Bruckner’s test can only tell you that this eye is potentially amblyopic, but cannot differentiate between refractive error or strabismus (an eye turn -- read more here).

The macula is the area of darkest pigmentation in the retina, so if light is focused here and reflecting back from our direct scope, we'd expect a dark, red reflex. If light is hitting another part of the retina, then the reflex won't be as dark or red, causing the abnormal Bruckner test response! via

Take Home:

Bruckner Testing gives you a quick way of assessing any potential for amblyopia, but won’t tell you the degree of amblyopia or the cause of the amblyopia. It’s a great way to find a problem, but it is only a starting place! Bruckner Test reflexes are especially useful because they can be used in screening young children when assessing visual performance isn’t always easy or accurate. And
Bruckner testing is reliable-- studies suggest an accuracy of 84% in amblyopia detection in patients with strabismus or a prescription difference of 3 diopters or more. The best part is that once you get comfortable, it takes less than 10 seconds to accurately perform this screening test and move to the next item on your list.

Dr. S is a pediatric and vision therapy specialist and COVD fellow practicing in St Louis, Missouri

Share |

Acuvue 1-Day Moist Define Review

Acuvue 1-Day moist Define review 7:00 AM

Share |

Glasses get a New Lenz Frenz

glasses case stuffed animal 7:00 AM

Ever wished that you could make wearing glasses more fun for your child or pediatric patient? Luckily glasses are a lot more stylish than they used to be, but there is still often a stigma that children associate with glasses wear that can make achieving their best visual performance and development a daily struggle. Luckily Texas based Lenz Frenz has an answer -- turn your glasses into something you share with your new stuffed animal friend!

The full Lenz Frenz product line can be found on www.mylenzfrenz.com

Lenz Frenz are stuffed animals that have a patent-pending hard case enclosed in a secret compartment in the back to serve as a glasses case, so that when a child isn't wearing their glasses they are safely stored within their toy. Sleeping over at a friend or family members house? Having to spend some time away from home for illness or medical treatment? The Lenz Frenz can be slept with just like any other stuffed animal, safely storing your child's glasses inside so that you don't have to worry about misplacing them during the time away from home. The stuffed animals also feature plastic or velcro temple pieces, so that your Lenz Frenz can also wear your glasses if you want to share the love.

Originally funded by a successful Kickstarter campaign, Lenz Frenz has 6 different stuffed animal designs for glasses and smaller keychain versions for contact lens storage. You can order any of the available designs from their website, and typically will be processed with same day shipping! Many opticals and hospitals are now offering Lenz Frenz throughout the US and Canada, so you may be able to find them locally as well.

Co-founder Molly Lofthouse created Lenz Frenz as a way to help bring joy to children that may find the process of dealing with glasses or contact lenses more difficult or stressful. She reports great customer feedback with children ages three to ten, but even tweens and teenagers may enjoy the keychain sized contact lens carriers. Every month on their Facebook page, Lenz Frenz shares the story of a child and their glasses with a monthly appointed Ambassador program -- a child that is enjoying the benefits of great vision with glasses wear and sharing the experience with their Lenz Frenz stuffed animal.

Share |