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In contrast to years past, especially from 2006 to 2009, where 'corneal staining' at two hours was a hot topic, there was almost no talk regarding the Andrasko grid.1 This is due to new compelling research that showed fluorescein is able to enter healthy, dividing cells2 and the signal seen with MPS solutions (PATH) is reversible and benign3-5 and occurs with all solutions, depending upon when viewed after lens insertion.1,6,7
What is more interesting is that the preservative polyquaternium-1 (Polyquad/PQ-1), which is found in several MPSs that show low levels of PATH at two hours, disrupts corneal cell membrane models at 7-8ppm; levels near (3ppm in RevitaLens OcuTec; AMO) or below (10ppm in Opti-Free Express and RepleniSH; Alcon) that found in three marketed solutions.3 This is in contrast to polyhexamethylene biguanide (PHMB), a preservative found in several of the solutions showing high levels of PATH at two hours, which had no effect on the same corneal cell membrane models up to 100 times that found in marketed solutions.
The new science presented at several meetings during 20104,5 and 20113 explains why this phenomenon occurs with certain preservatives at certain time points after lens insertion and has no pathological sequelae. This is further supported by new, more rigorous studies in the literature that showed PATH is not associated with symptoms, such as reduced comfort,8,9 and neither corneal staining (as observed during continuous wear) nor PATH are associated with corneal infiltrates,10-12 in contrast to previously published findings that have now been retracted.13,14
Clinically relevant findings
A very relevant concern to eye care practitioners (ECPs), non-infectious corneal inflammatory events, such as contact lens-associated infiltrates/infiltrative keratitis, as an increase in the incidence has been noted by a large proportion of ECPs; especially those in large-volume practices, those that specialise in contact lenses, and those at referral practices.15,16 Reports of an increase in the frequency of infiltrative keratitis (IK)/contact lens-associated infiltrative keratitis (CLAIK) associated with Opti-Free RepleniSH and silicone hydrogel (SiH) lenses were first observed in 2008 with an increasing number published17-20 and presented at meetings21-24 in the subsequent years with ever increasing frequency. What is of even greater concern is that Opti-Free RepleniSH25 is more closely associated with symptomatic IK (unhappy, red irritated eyes that come into your practice or call you after-hours).17 Moreover, of the symptomatic cases of IK/CLAIK, RepleniSH MPS with SiHs, especially senofilcon A (Acuvue Oasys; Vistakon), the most popular contact lens, is significantly associated (both p<0.01) with those of the greatest severity.23
The data regarding which SiH lens material is associated with infiltrates is not as clear cut. Reports have implicated senofilcon A,18,19,21,23 lotrafilcon A (Night&Day; CIBA Vision),17 and lotrafilcon B (AirOptix; CIBA Vision)18 as well as no lens association was found with infiltrates though Opti-Free/Opti-Free RepleniSH remained an associated factor.22,24
It's becoming harder to ignore this problem reported by so many clinicians and its impact on patients. This is especially true in the current economic climate as the total costs per non-severe (most likely not infectious) and severe CIEs (most likely infectious) were estimated to be $1,002.90 and $1,496.00, respectively.26
Bacterial bioburden, compliance and infiltrates
Recently published studies confirm that lens and lens case bioburden is associated with an increase in infiltrates.11,27,28
New research showed that there was a statistically higher level of bioburden in contact lens cases with any contamination of Opti-Free RepleniSH users (p=0.0001) and both significantly more lens cases and level of bioburden within these cases with gram negative bacteria of Opti-Free RepleniSH users (p=0.0001), while cases of those using a PHMB-based MPS and hydrogen peroxide were similar.29 In this same study, the cases of Opti-Free Express users showed the lowest contamination rate and bacterial bioburden level for any contamination and specifically for gram-negative bacteria (p=0.0001). These findings show high agreement with the Carnt et al study published in 2009,17 as well as the case series by Kislan, where the vast majority of patients were RepleniSH users, with only one case in an Opti-Free Express user.23
The importance of hand washing or the lack thereof with regard to complications, including 'sterile' infiltrates30 and microbial keratitis,31 comes up again and again. As clinicians, the majority of us (~92 per cent) recommend rubbing and rinsing contact lenses as part of the cleaning process.32 We do this for a reason, and should stop recommending MPS products that don't meet with our professional standard recommendation.
Applying research to improve patient outcomes
Until we have more information there are several practical tactics that can be incorporated into your practice to reduce the likelihood of your patients experiencing an infiltrative event:
? Make specific recommendations regarding solutions and why, including:
- A solution that has a new lens case included with the purchase of a new bottle of solution. And encourage them to throw the old one out!
- A solution with rub and rinse regimen which aids in decreasing lens bioburden
- Recommend to new patients and switch current patients to lens care systems not associated with high rates of infiltrative keratitis events and educate patients that there have been a lot of cases of inflammatory problems with one of these lens care systems
? Give specific instructions on proper lens hygiene, including a demonstration on how to wash one's hands, lenses, and lens cases between each use
? Keep abreast of contact lens complications by attending scientific meetings and engaging in an ongoing dialogue with colleagues
- As practitioners we should be reporting these adverse events to the manufacturer as well as on the FDA's MedWatch website
? Most importantly, stay informed by taking the time to review the current literature in addition to research presented at meetings to make decisions based on strong scientific evidence rather than based on grids where the evidence is less than rigorous and the conclusions are erroneous and driven by a marketing machine under the guise of one or two consultants purporting independence from a manufacturer. ?
References
1 Andrasko G, Ryen K. A series of evaluations of MPS and silicone hydrogel lens combinations. Rev Cornea Contact Lenses, March 2007:36-42.
2 Bakkar M, Maldonado-Codina C, et al. Development of an in-vitro model of solution induced corneal staining. Optom Vis Sci, 2010;87(suppl):E-abstract 100959.
3 Bright FV, Maziarz P, et al. PHMB and PQ-1 impact on a liposome corneal surface membrane model. Invest Ophthalmol Vis Sci, 2011;52:E-Abstract 6491.
4 Bright FV, Maziarz P, et al. Cell membrane integrity modeling with polyaminopropyl biguanide (PHMB) exposure using fluorescent spectroscopy and liposome assays. The 6th Biennial Scientific Symposium of the Contact Lens Association of Ophthalmologists Education & Research Foundation; 2010 September 23-25; Las Vegas, NV.
5 Bright FV, Maziarz P, et al. Using a liposome cell membrane model to evaluate corneal surface integrity with high dosage oolyaminopropyl biguanide (PHMB) exposure. The Annual Global Specialty Lens Symposium; 2010 January 27-30; Las Vegas, NV.
6 Garofalo RJ, Dassanayake N, et al. Corneal staining and subjective symptoms with multipurpose solutions as a function of time. Eye Contact Lens, 2005;31(4):166-74.
7 Kislan T. An evaluation of corneal staining with 2 multipurpose solutions. Optometry, 2008;79(suppl):330.
8 Willcox MD, Phillips B, et al. Interactions of lens care with silicone hydrogel lenses and effect on comfort. Optom Vis Sci, 2010;87(11):839-46.
9 Sorbara L, Peterson R, et al. Multipurpose disinfecting solutions and their interactions with a silicone hydrogel lens. Eye Contact Lens, 2009;35(2):92-7.
10 Carnt NA, Keay L, et al. Risk factors associated with corneal inflammation in soft contact lens daily wear. Invest Ophthalmol Vis Sci, 2007;48(suppl):E-Abstract 4326.
11 Szczotka-Flynn L, Lass JH, et al. Risk factors for corneal infiltrative events during continuous wear of silicone hydrogel contact lenses. Invest Ophthalmol Vis Sci, 2010;51(11):5421-30.
12 Willcox M. Ophthalmic Devices Panel Meeting. Food and Drug Administration Ophthalmic Devices Advisory Panel. Washington, DC: Food and Drug Administration, 2008.
13 Szczotka-Flynn L, Debanne SM, et al. Predictive factors for corneal infiltrates with continuous wear of silicone hydrogel contact lenses. Arch Ophthalmol, 2007;125(4):488-92.
14 Carnt N, Jalbert I, et al. Solution toxicity in soft contact lens daily wear is associated with corneal inflammation. Optom Vis Sci, 2007;84(4):309-15.
15 Kislan TP, Hom MM. Corneal infiltrates with multipurpose solutions and contact lens combinations. Invest Ophthalmol Vis Sci, 2010;51(suppl):E-Abstract 3424.
16 Shovlin J, Eiden SB, et al. Infiltrative keratitis in daily lens wearers: do you see what I see? Contact Lens Spectrum, April 2011;26(suppl).
17 Carnt NA, Evans VE, et al. Contact lens-related adverse events and the silicone hydrogel lenses and daily wear care system used. Arch Ophthalmol, 2009;127(12):1616-23.
18 Hine N. Hypersensitivity with Silicone Hydrogels: Material or Solution Effect? In the Practice. September ed: www.siliconehydrogels.org, 2008.
19 Kislan T. Recent increase in contact lens-associated infiltrative keratitis. Optician, February 2011:14-16.
20 Sacco AJ. Contact lens-associated infiltrative keratitis and multipurpose solutions. Contact Lens Spectrum, 2011;26(4):40-45.
21 Sacco A. Silicone hydrogel contact lenses, lens care and sterile infiltrates: is there a connection? The Annual Global Specialty Lens Symposium; 2011 January 27-30; Las Vegas, NV.
22 Reeder R. Trends associated with corneal infiltrative events in soft lens wearers. The Annual Global Specialty Lens Symposium; 2011 January 27-30; Las Vegas, NV.
23 Kislan TP. Case characteristics of persons presenting with contact lens-associated infiltrative keratitis (CLAIK) with multipurpose solutions and contact lens combinations. Invest Ophthalmol Vis Sci, 2011;52(suppl):E-Abstract 6521.
24 Diec J, Evans VE, Naduvilath TJ. Performance of polyquad, PHMB and peroxide solutions with silicone hydrogel lenses. Invest Ophthalmol Vis Sci, 2009;50(suppl):E-Abstract 5633.
25 Nichols J. Contact lenses 2010. Contact Lens Spectrum, 2011;26(1):24-28.
26 Smith AF, Orsborn G. Estimating the annual economic burden of illness due to corneal infiltrative events in the United States. Invest Ophthalmol Vis Sci, 2011;52(suppl):E-Abstract 5537.
27 Kiernan DF, Chin EK, et al. Multiple drug-resistant Alcaligenes xylosoxidans keratitis in a sanitation worker. Eye Contact Lens, 2009;35(4):212-4.
28 Ozkan J, Mandathara P, et al. Risk factors for corneal inflammatory and mechanical events with extended wear silicone hydrogel contact lenses. Optom Vis Sci, 2010;87(11):847-53.
29 Willcox MD, Carnt N, et al. Contact lens case contamination during daily wear of silicone hydrogels. Optom Vis Sci, 2010;87(7):456-64.
30 Radford CF, Minassian D, et al. Risk factors for nonulcerative contact lens complications in an ophthalmic accident and emergency department: a case-control study. Ophthalmology, 2009;116(3):385-92.
31 Bourcier T, Sauer A, The French Study Group for Contact Lens-related Microbial Keratitis. Risk factors for contact lenses related microbial keratitis: a prospective multicenter case-control study. Invest Ophthalmol Vis Sci, 2011;52:E-Abstract 6516.
32 Wu Y, Carnt N, Willcox M, Stapleton F. Contact lens and lens storage case cleaning instructions: whose advice should we follow? Eye Contact Lens, 2010;36(2):68-72.
Acknowledgment: The author thanks BioScience Communications, New York for editorial and scientific support.
? Marc Bloomenstein is director of optometric services at the Schwartz Laser Eye Center in Scottsdale, Arizona. He acknowledged no financial interest in the products or companies mentioned. DrBloomenstein@schwartzlaser.com