For a number of years, the contact lens community was focused on oxygen permeability associated with safe contact lens wear. More recently, we've seen the general interest expand into comfortable contact lens wear. Many contact lens related factors have been considered in this discussion including things such as oxygen permeability, water content, modulus, and friction. However, I was reminded recently to also not forget about design considerations. We know that the design of a lens—including characteristics such as its thickness and edge profile—can also play a role in comfortable contact lens wear for both our soft and GP lens wearers.
Advanced Vision Technologies (AVT), a Denver based specialty contact lens manufacturer, has been cleared by the FDA to manufacture advanced, customized lens designs in the Contamac Definitive silicone hydrogel material.
The new product line of silicone hydrogel specialty lenses is called NaturaSOFT with True Fit Technology which is being made available in spherical, toric, multifocal, and irregular cornea designs. NaturaSOFT with True Fit Technology allows the practitioner to fit the actual sagittal depth of a patient's cornea for a more precise fit, per the company. All indications for use and designs are cleared by the FDA for daily wear and all are available in customizable parameters. The new lenses are available in a quarterly replacement modality with an industry leading warranty program.
Advanced Vision Technologies manufactures premium GP Contact Lenses with innovative designs, such as torics, multifocals, post-surgical, keratoconus, scleral, pediatric, corneal reshaping and Naturalens designs and now adds a full line of Definitive silicone hydrogel customized soft contact lenses.
Please call 888-393-5374 for more information or email AVT at: firstname.lastname@example.org.
With a growing customer base in the United States, Safigel is adding more plus powers to its daily disposable line and is now offering +2.00 to +4.00 in quarter steps, in addition to +0.50 to +2.00 already offered in those increments.
Safigel is the only contact lens with the same Sodium Hyaluronate (HA) found in dry eye drops. According to the company, over a day of wear, the common symptoms of dryness in regular contact lens wearers are lessened with Safigel 1 day,1 with the added advantage of HA contributing to a stable tear film and epithelial growth.2
1. DeMartin G. A new lens for dry eye - a comparative trial. Optician. 2006, Dec 1; 232: 6080: 30-31.
2. Nishida T, Nakamura M, Mishima H, Otori T. Hyaluronan Stimulates Corneal Epithelial Migration. Experimental Eye Research. 1991; (53): 753-758.
UK contact Lens manufacturer UltraVision CLPL announced the appointment of Graham Avery as new Sales Director. Graham comes to UltraVision CLPL with more than thirty years' experience in the contact lens industry from running his own business to sales and marketing director of David Thomas Contact Lenses and more recently as Global Export Manager of Menicon. He has a track record of success in introducing speciality contact lens designs into the market in both the United Kingdom and export markets.
The U.S. Food and Drug Administration (FDA) is warning the public that accidental ingestion by children of over-the-counter (OTC) eye drops used to relieve redness and nasal decongestant sprays can result in serious harm. The eye drops and nasal sprays that have been involved in the cases of accidental ingestion contain the active ingredients tetrahydrozoline, oxymetazoline, or naphazoline. These products are sold under various brand names, such as Visine, Afrin, Dristan and Mucinex, as generics, and as store brands.
FDA identified 96 cases of accidental ingestion of products containing tetrahydrozoline, oxymetazoline, or naphazoline by young children, reported between 1985 and October 2012. The children ranged in age from 1 month to 5 years. Fifty-three cases reported hospitalization due to symptoms including nausea, vomiting, lethargy, tachycardia, decreased respiration, bradycardia, hypotension, hypertension, sedation, somnolence, mydriasis, stupor, hypothermia, drooling, and coma.
The amounts ingested ranged from 0.6 mL to one and one-half bottles (products are packaged in 15-mL and 30-mL bottles). An article by Spiller et al.1 states that 2 mL to 5 mL of tetrahydrozoline 0.05% solution is capable of producing coma in a child. Additionally, two literature reports indicate that a 1.5 mL to 3 mL volume produced severe adverse events such as central nervous system and respiratory depression, and bradycardia in a 25-day-old infant and a 2-year-old child.2,3
In January, 2012, the U.S. Consumer Product Safety Commission (CPSC) proposed a rule to require child-resistant packaging for all products containing at least 0.08 mg of an imidazoline derivative. However, this rule has not been finalized. In addition, FDA's Division of Medication Error Prevention and Analysis (DMEPA) is partnering with CPSC to warn consumers about the need to keep these products safely out of the reach of children.
1. Spiller HA, Rogers J, Sawyer TS. Drug facilitated sexual assault using an over-the-counter ocular solution containing tetrahydrozoline (Visine). Legal Medicine. 2007;9:192-5.
2. Katar S, Taskesen M, Okur N. Naloxone use in a newborn with apnea due to tetrahydrozoline intoxication. Pediatr Int. 2010;52:488-9.
3. Tobias JD. Central nervous system depression following accidental ingestion of Visine eye drops. Clin Pediatr (Phila). 1996;35:539-40.
International Vision Expo & Conference opened the voting in an online contest featuring student-made videos. Armed with handheld video cameras, students from 21 of the schools of optometry were challenged to record their experience at International Vision Expo. The footage was professionally edited to create a short video that captures testimonials, exhibit hall and continuing education, city sights, exclusive student parties and networking events — all from a student perspective. And, you can vote for your favorite! Alumni are welcome to vote.
All 21 videos are featured on Facebook and can be accessed through a link on International Vision Expo East's website, www.visionexpoeast.com/videochallenge. Online voting will remain open through Friday, November 9. Video links can be shared with classmates, alumni, colleagues, friends and family. Voters must be logged in to a Facebook account. Only one vote will count per person. Winners will be announced by Friday, November 16.
The top three winners will be awarded a donation to their school, in the amount of $2,500 (first place), $1,000 (second place) and $500 (third place). In addition, the first place winner will receive an exclusive off-site party hosted by International Vision Expo and the second place winner will be awarded a pizza party. Each student from the top three schools will also get a swag bag.
Hand Hygiene Lapses by Practitioners Can Be Another Way to Lose A Patient Charles McMonnies, Adjunct Professor, School of Optometry and Vision Science, University of New South Wales, Australia
As a result of publishing on the topic: (McMonnies CW. Hand hygiene prior to contact lens handling is problematical. Cont Lens Ant Eye 2012; 35(2): 65-70), I received an email from a patient reporting her concerns that her optometrist's hand-washing prior to inserting her contact lens was unsatisfactory. Hand hygiene performed without a patient seeing it being done allows for the assumption that it has been neglected. Seeing is believing. However the email indicated that patients may not be impressed when they do have the chance to observe their practitioner's standards of hygiene.
Rather than being a burden for practitioners I suggest this potential problem can be regarded as an ideal opportunity to educate and re-educate patients on how they should be washing their hands. Patients don't often realize that soap lather is a suspension of loosened germs making it necessary to emphasize rinsing to ensure complete lather removal for example; or that washed hands are recontaminated by hot air driers, reused towels, tap and door handles for example. Practitioners washing their hands can very usefully take the opportunity to explain such details to their patient, so that they can be reassured that the practitioner is competent in this area, while at the same time receiving advice that will help them to improve their own standards.
For more suggestions on the types of advice that can be appropriate in this situation, practitioners can contact me at email@example.com. These documents are Word files which can be easily adapted for use in individual practices. ^ Back to top
Blanching in Scleral Lens Fit By Augusto Rosse, Santiago, Chile
This picture shows a light blanching in a patient fit with a scleral lens. One can see the blood vessels and how those appear cut in the edge of the lens. This is a common issue that should be solved.
We thank Augusto Rosse for his photo and welcome photo submissions from our other readers! It is easy to submit a photo for consideration for publishing in Contact Lenses Today. Simply visit http://www.cltoday.com/upload/upload.aspx to upload your image. Please include an explanation of the photo and your full name, degree or title and city/state/country. ^ Back to top
RESEARCH REVIEW Loretta B. Szczotka-Flynn, OD, PhD, MS, FAAO
Input From the FDA on Preservative Uptake and Release
Previous issues of Contact Lenses Today have highlighted how the U.S. Food and Drug Administration (FDA) has been active over the last several years in working to develop new guidance regarding contact lenses and care solutions. In the Oct 14, 2012 edition, the Abstract column pointed out two upcoming related articles to be published in Eye & Contact Lens in 2012.
A third article is also in press authored by several members and branches of the Center for Devices and Radiological Health within the FDA. This article by Green et al, discusses material properties that predict preservative uptake for silicone hydrogel contact lenses.
The authors assessed material properties that could affect preservative uptake by silicone hydrogel lenses. Specifically, they evaluated the water content, effective pore size, and preservative uptake of silicone and conventional hydrogel soft contact lenses. They found that the water content of the lens materials and ionic charge are associated with the degree of preservative uptake; and commented that the current grouping system for testing contact lens-solution interactions which separates all silicone hydrogels from conventional hydrogel contact lenses may not be that straightforward.
Based upon the results of their research, they propose that the same material characteristics used to group conventional hydrogel lenses (water content and ionic charge) can also be used to predict uptake of hydrophilic preservatives for silicone hydrogel lenses. This may better explain the differences in preservative uptake between silicone hydrogel lens types. In addition, the hydrophobicity of silicone hydrogel contact lenses, although not investigated in that study, is a unique contact lens material property that the authors propose should be evaluated for the uptake of relatively hydrophobic preservatives and tear components.
Green JA, Phillips KS, Hitchins VM, Lucas AD, Shoff ME, Hutter JC, Rorer EM, Eydelman MB. Material Properties That Predict Preservative Uptake for Silicone Hydrogel Contact Lenses. Eye Contact Lens. 2012 Nov;38(6):350-357. ^ Back to top
MATERIALS & DESIGNS Ronald K. Watanabe, OD, FAAO
Scleral lenses: how big?
Scleral lenses have taken off tremendously over the past few years. They have advantages over both soft and GP lenses, including good initial comfort, stable vision, and the ability to vault over and neutralize (largely) virtually any corneal irregularity. Therefore, scleral lenses have become a great problem solver and sometimes the lens of choice for some practitioners. They are also becoming more "mainstream" with designs targeting the "normal" cornea.
One aspect that I often wonder about is diameter selection. Scleral lenses range in diameter from about 13.5 mm to over 24 mm, though most are between 15 and 18 mm. Diameter selection depends on a lot of things, including HVID, the degree of corneal irregularity, the reason for fitting, and fitting philosophy. The larger you go, the more you distribute lens mass across the sclera, but the more you have to deal with scleral toricity and irregularity. The smaller you go, the easier it is to insert and remove, but you will more likely cause impingement because of smaller landing zones. I think that diameter selection is a decision based on individual ocular characteristics, and it may take a few adjustments to achieve the best diameter for your patient. ^ Back to top
Corticosteroids for Bacterial Keratitis: The Steroids for Corneal Ulcers Trial (SCUT)
This group of researchers wanted to determine whether there is a benefit in clinical outcomes with the use of topical corticosteroids as adjunctive therapy in the treatment of bacterial corneal ulcers.
This was a randomized, placebo-controlled, double-masked, multicenter clinical trial comparing prednisolone sodium phosphate, 1.0%, to placebo as adjunctive therapy for the treatment of bacterial corneal ulcers. Eligible patients had a culture-positive bacterial corneal ulcer and received topical moxifloxacin for at least 48 hours before randomization.
The primary outcome measured was best spectacle-corrected visual acuity (BSCVA) at 3 months from enrollment. Secondary outcomes included infiltrate/scar size, reepithelialization, and corneal perforation.
Between September 1, 2006, and February 22, 2010, 1769 patients were screened for the trial and 500 patients were enrolled. No significant difference was observed in the 3-month BSCVA (-0.009 logarithm of the minimum angle of resolution [logMAR]; 95% CI, -0.085 to 0.068; P = .82), infiltrate/scar size (P = .40), time to reepithelialization (P = .44), or corneal perforation (P > .99). A significant effect of corticosteroids was observed in subgroups of baseline BSCVA (P = .03) and ulcer location (P = .04). At 3 months, patients with vision of counting fingers or worse at baseline had 0.17 logMAR better visual acuity with corticosteroids (95% CI, -0.31 to -0.02; P = .03) compared with placebo, and patients with ulcers that were completely central at baseline had 0.20 logMAR better visual acuity with corticosteroids (-0.37 to -0.04; P = .02).
The researchers concluded that they found no overall difference in 3-month BSCVA and no safety concerns with adjunctive corticosteroid therapy for bacterial corneal ulcers. Application to Clinical Practice: Adjunctive topical corticosteroid use does not improve 3-month vision in patients with bacterial corneal ulcers.
Srinivasan M, Mascarenhas J, Rajaraman R, et al. Corticosteroids for bacterial keratitis: the Steroids for Corneal Ulcers Trial (SCUT). Arch Ophthalmol. 2012 Feb;130(2):143-50 ^ Back to top