Did you know that there are some countries in which contact lenses are sold in vending machines? Contact lens practices can vary substantially around the world, in terms of who can prescribe contact lenses in addition to the way that contact lenses are regulated and distributed. Although there are often frustrations associated with some patients and their lack of understanding of medical devices and safety, practitioners located in countries with greater regulation should consider themselves fortunate.
Lagado Corporation, a wholly owned subsidiary of Menicon America, Inc., announced that it has received FDA clearance for Lagado LSH (mangofilcon A), a new silicone hydrogel material for use in contact lenses. Formulated to meet the growing demand for made-to-order silicone hydrogel lenses, this mid-range water content (49%) material can be used in a wide variety of designs. Lagado LSH lenses will be plasma oxidized to produce a low wetting angle and improved wettability - helping to promote lens comfort, improve visual performance, and reduce the potential for deposits. Additionally, the LSH material has a unique combination of physical properties that make it stable, durable and easy to handle, according to the company.
In the United States, the company will begin working closely with a select group of independent, custom lens laboratories. Each lab is required to submit and receive FDA clearance for lenses offered in the Lagado LSH material. The company anticipates that Lagado LSH lenses will be available later this year.
Rigel Pharmaceuticals, Inc. has developed a topical ophthalmic (eye drop) formulation of R348, a JAK/SYK inhibitor, aimed at reducing the underlying inflammation responsible for causing the symptoms of dry eye disease. According to the company, a recently completed Phase 1 study of R348 in patients with dry eye disease showed that the drug candidate is well tolerated and Rigel expects to begin a Phase 2 study, titled DROPS (Dry eye Rigel Ophthalmic Phase 2 Study), shortly.
This multi-center, randomized, double-masked study, will evaluate two doses of R348 versus placebo administered twice a day over a three-month period in approximately 210 patients with dry eye disease. The efficacy endpoints will include change from baseline in corneal staining, tear production and dry eye symptom scores. Results of this Phase 2 study are expected in the first half of 2014.
Rigel Pharmaceuticals, Inc. is a clinical-stage drug development company that discovers and develops novel, small-molecule drugs for the treatment of inflammatory and autoimmune diseases, as well as muscle disorders.
Bausch + Lomb (B+L) has received approval from the U.S. Food and Drug Administration (FDA) for the Trulign Toric posterior chamber intraocular lens (IOL). The Trulign Toric intraocular lens is the first toric IOL that corrects for astigmatism and, unlike other standard toric lenses, has the additional capacity to deliver improved vision across a natural range of focus. The lens is intended for primary implantation in the capsular bag of the eye for the visual correction of aphakia and postoperative refractive astigmatism secondary to removal of a cataractous lens in adult patients with or without presbyopia who desire reduction of residual refractive cylinder with increased spectacle independence and improved uncorrected near, intermediate and distance vision.
Soft Contact Lens After a Penetrating Injury By Jaime Ibanez, OD, Villavicencio, Columbia
Even though the cornea was compromised, the visual axis remained intact. The lens was surgically removed (aphakic) and a peripheral retinal detachment was managed with a scleral buckle. A high powered positive soft contact lens was fitted as a bandage until the anterior segment returns back to normal. The plan is to then proceed to fit a scleral GP lens.
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In my last column, I wrote about the possibility of correcting up to 10 D of myopia with a few available extreme orthokeratology lens designs. It was pointed out to me by an esteemed colleague that the use of orthokeratology lenses for the correction of more than 5 or 6 D of myopia is an off-label use of these devices. For Paragon CRT lenses, the FDA approved limit is -6.00 D, while for B+L VST lenses, the FDA approved limit is -5.00 D. Though we, as contact lens practitioners, can prescribe lenses for off-label use when we find it appropriate, we have to be careful when doing so. In this case, we don't have evidence of the relative safety of correcting such high levels of myopia as compared to the approved levels. Though it is effective and appears to be safe, we must monitor these patients diligently. This is a good reminder that with all contact lens fitting, we must be cognizant of the risks of lens wear, especially with special designs and/or compromised corneas.
RESEARCH REVIEW Loretta B. Szczotka-Flynn, OD, PhD, MS, FAAO
Endothelial Keratoplasty and Post Operative Contact Lens Fitting Needs
Endothelial keratoplasty (EK) is a superior technique compared to full thickness penetrating keratoplasty (PK) for improving rehabilitation and spectacle corrected visual acuity after transplant. As a clinician, I rarely see patients referred for contact lens fitting after EK, whereas about 50% of PK patients are candidates for contact lenses after surgery.
Although posterior corneal HOAs are significantly higher in eyes after Descemet's stripping automated endothelial keratoplasty (DSAEK), anterior corneal HOAs are not significantly different in eyes that undergo DSAEK compared to controls.1 Therefore, it is unknown how many patients will actually benefit from contact lens correction of corneal irregularity after EK.
A recent paper by van Dijk et al from The Netherlands explored this very question. They evaluated the incidence and causes of anterior corneal surface irregularities after successful Descemet membrane endothelial keratoplasty (DMEK) and the efficacy of contact lens fitting in these cases.2
In a series of 262 DMEK surgeries, 23 eyes (9%) were fitted with contact lenses. Indications for contact lens fitting included (1) obvious corneal surface irregularities due to preexisting corneal scarring, (2) surface irregularities associated with longstanding preoperative stromal edema, and (3) undetectable optical imperfections. They also concluded that prolonged preoperative corneal edema for more than 12 months was a risk factor for diffuse irregular astigmatism after DMEK.
This is a helpful survey for practitioners sending their FECD and PBK patients for EK; up to 10% of such subjects may best be served with contact lenses once their surgery is complete.
1. Muftuoglu O, Prasher P, Bowman RW, McCulley JP, Mootha VV. Corneal higher-order aberrations after Descemet's stripping automated endothelial keratoplasty. Ophthalmology. 2010 May;117(5):878-884.
2. van Dijk K, Parker J, Liarakos VS, Ham L, Frank LE, Melles GR. Incidence of irregular astigmatism eligible for contact lens fitting after Descemet membrane endothelial keratoplasty. J Cataract Refract Surg. 2013 May 8. [Epub ahead of print]
A Randomized Clinical Trial to Assess the Effect of a Dual Treatment on Myopia Progression: The Cambridge Anti-Myopia Study
The purpose of this study was to evaluate the effect of a dual treatment modality for myopia, by improving accommodative functions, on myopia progression.
A double blind randomized control trial was conducted on 96 subjects. The treatment modality for the trial employed custom designed contact lenses which control spherical aberration in an attempt to optimise static accommodation responses during near-work, and a vision-training programme to improve accommodation dynamics. Myopia progression was assessed over a 2-year period using cycloplegic autorefraction and biometry.
The mean progression was found to be -0.33 Diopters (D) over the 2 years of the study. There was no interaction between contact lens treatment and vision training treatment at 24 months (p = 0.72). There was no significant treatment effect of either Vision Training or Contact Lens Spherical Aberration control on myopia progression.
The researchers concluded that this study was unable to demonstrate that the progression of myopia can be reduced over a 2-year period by either of the two treatments aimed at improving accommodative function. Neither treatment group (contact lens or vision training) progressed at a slower rate over the 2 years of the study than did the appropriate control group.
Allen PM, Radhakrishnan H, Price H, et al. A randomised clinical trial to assess the effect of a dual treatment on myopia progression: The Cambridge Anti-Myopia Study. Ophthalmic Physiol Opt. 2013 May;33(3):267-76.