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Thank you very much for taking the time to sign up for the No Blur! EyeMail Newsletter. The No Blur! EyeMail Newsletter is sent out approximately four times per year. The newsletter will contain the most recent developments in eyecare today, interesting information about your eyes, as well as a fun item. You can view the previous No Blur! EyeMails by clicking the online archive icon above. You can also send any comments or suggestions about the No Blur! EyeMail down in the related links section below.

 
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A Message From Dr. Maller

20/20 doesn't necessarily equal 20/20. Alright Dr. Maller, you've lost it now. Well despite the seemingly incongruous statement above, I haven't lost it at all. Although 20/20 is probably the single most recognizable measurement regarding vision, the typical person doesn't really understand what 20/20 actually means ( for an explanation of 20/20, please click here .) Well, as has come to light (pardon my pun) in the last decade or so, the 20/20 "symbol" seems to have even more mystery surrounding it as demonstrated by many of the post-surgical patients that I see. 20/20 is an acuity measurement but doesn't measure or accurately describe the quality of the acuity being measured. This means that one person can see 20/20 and it appears distinct, crisp, and well defined, while another person can see 20/20 but it appears faded, shadowed, and smeared. Although both of these individuals can see 20/20, the quality of what the second person sees is obviously very inferior. A common theme among the post-surgical (RK, LASIK, etc.) patients that I provide care for, is that they saw their doctor and was told that they can see 20/20, yet the patient still complains that the vision doesn't look very good. Since the typical person associates 20/20 with good vision, they are left confused (and even doubting their own sanity) since they can read the 20/20 line on the chart, yet they still seem to have varying degrees of difficulty functioning out in the real world. Further frustration is experienced by these people since they tell their friends and family that they see 20/20 in the doctor's office but it is very difficult if not impossible for them to drive a car at night or stare at a computer screen to do their work. Their friends and family tell them that "you see 20/20 - it must be in your head and you are imagining the problems." ( You can read some of their stories to appreciate their difficulties and frustrations here .) This is obviously very unfortunate since these individuals have some very difficult vision problems, yet the problems and difficulties associated with this poor quality vision are being dismissed. I believe that until terms like "spherical aberration, coma, trefoil, contrast sensitivity, etc." make it into common language like 20/20 has, these people will continue to be frustrated by trying to describe their vision problems.  Fortunately, I am happy to see that the professional side of vision care is starting to recognize these issues as is demonstrated by the first story below. Much more research needs to be done in this area since this subset of vision problems is continuing to rise due to the numbers of post-surgical patients.  Vision is much more complex than 20/20 and it is important that the average person in the street comes to understand that quality of vision is not recognized by the 20/20 symbol. If you know someone that is describing vision problems despite the fact that they are 20/20, please share this information with them.

Dr. Maller

 

Higher Order Aberrations In Keratoconus Patients Corrected With Gas Permeable Lenses

A study was undertaken to examine the effects of higher-order aberrations in Keratoconus when corrected with gas permeable lenses. This was a small study comparing Keratoconus patients wearing gas permeable lenses to normal cornea patients wearing gas permeable lenses. In particular, the study showed significant differences in these two groups comparing the contrast sensitivity, coma, and spherical aberrations. The Keratoconic patients exhibit much higher coma and spherical aberrations in addition to much lower contrast sensitivity. This was true despite the fact that the Keratoconic patients were capable of achieving 20/20 snellen acuity. Higher coma and spherical aberrations corroborates what I typically find clinically in that Keratoconic patients will often describe seeing "ghosts" or "shadows" in addition to seeing the actual letters on the chart. This underscores the concept of all 20/20 vision is not the same and that there can be significant differences in the quality of the image.

 

What Do People Know About Glaucoma?

In a recent survey, knowledge about glaucoma was tested through a questionnaire using three different groups of people. The three groups were people without glaucoma, people who were recently diagnosed with glaucoma and people that have had glaucoma for an extended period of time. Although the people who had glaucoma scored better than the people without glaucoma, they had many misperceptions about the condition just like the people who didn't have glaucoma. For example, 80% of all the participants thought that topical medications could not have systemic side effects; 48% of established glaucoma patients believed that symptoms would warn them of disease progression; and 33% of new glaucoma patients believed that blindness is a common outcome of glaucoma. Given the apparent lack of information along with the overwhelming amount of misinformation regarding this disease, educational programs and materials need to be tailored to bring proper glaucoma information to the public.

 

Dry Eye and Contact Lenses

Dry eye has long been identified as the most common reason for contact lens failure. As reviewed in a recent article, many of the deficiencies of a particular eye can be better addressed by proper contact lens selection. Unfortunately along with the explosion of disposable contact lens usage there has been a certain perception created that contact lenses are all interchangeable. Nothing could be further from truth. Health and comfort of the eye's surface is affected by the water content, ionicity, oxygen permeability, along with lens surface properties such as protein, lipid, and mucin deposition, protein adsorption, and wettability. These are just some of the variables that will have impact on a contact lens' performance. Almost equally important to the contact lens selection are the contact lens solutions used since compatibility of the solution with the specific contact lens, action, cytotoxicity, and biocompatibility will also play a significant role in overall lens performance for the contact lens wearer. Careful selection of the contact lens and associated contact lens solutions as well as appropriate management of the underlying causes of the dry eye can bring contact lens success to the dry eye patient.

 

Screening Diabetic Patients Is Insufficient

A study examined the relationship of visual acuity measurement, type of diabetes, sight-threatening diabetic retinopathy, and other ocular diabetic related problems. Diabetes is a leading cause of vision loss. The results of this study demonstrated that the majority of visual loss in a population with diabetes is due to causes other than diabetic retinopathy. Visual acuity alone is not a reliable criterion in predicting sight-threatening diabetic retinopathy. Screening for diabetic retinopathy as well as acuity screening is insufficient to properly identify the factors responsible for visual loss in diabetic patients. This further justifies frequent comprehensive eye examination of diabetic patients.

 

Bacterial Adhesion In Conventional Soft Lenses Vs. Silicone Hydrogels

Certainly one of the hottest topics in soft contact lens technology over the past few years has been the introduction of Silicone Hydrogel materials. These materials allow a significant increase in the amount of oxygen that will be transmitted through the lens material. The general public has made the erroneous assumption that more oxygen means more comfort. Although this equation is certainly not always true, the assumption of more oxygen getting to the eye i.e. allowing the eye to breathe better, intuitively should mean that the lenses are safer to wear. In a recent in vitro study, the ability of bacteria to adhere to a conventional soft lens vs. a silicone hydrogel lens was examined. Across the entire spectrum of bacterial species that were tested, the silicone hydrogel lenses had much greater adherence of bacteria as compared with the conventional soft lens materials. In fact, Pseudomona aeruginosa (a particularly aggressive strain that is of great concern regarding contact lens wearers) was adherent to the Silicone Hydrogel material lotrafilcon B (O2 Optix) by at least 20 times greater than both Staphylococcus epidermidis strains that were used. Although this was an in vitro study, this does raise concern about the overall impression that more oxygen through a lens means less risk of infection. Of course the best way to control risk of infection; is to avoid contact lens abuse by overwear, proper contact lens care and hygiene, and regular visits to your eye doctor.

 

Just For Fun - Button Hunt 3

Sometimes while on the web, I will come across some item that is just fun. I have incorporated this into the website because everyone should have a little fun occasionally. I have decided to put at least one "fun" thing into each newsletter. I hope that you enjoy it. This particular item is called Button Hunt 3. This is a puzzle game that requires some out-of-the-box thinking. The instructions are under the button labeled "tutorial." Good Luck! You can find this puzzle at Button Hunt 3.