ORIGINAL ARTICLE

Quantification of Non-Polar Lipid Deposits onSenofilcon A Contact Lenses

Miriam Heynen*, Holly Lorentz*, Sruthi Srinivasan†, and Lyndon Jones‡

ABSTRACTPurpose. To quantify non-polar lipids deposited on senofilcon A silicone hydrogel contact lenses (J&J Acuvue OASYS)when disinfected with a no-rub one-step hydrogen peroxide system (CIBA Vision ClearCare) and a care system preservedwith Polyquad & Aldox (Alcon OPTI-FREE RepleniSH).Methods. Thirty existing soft lens wearers symptomatic of dryness were enrolled into a 4-week prospective, randomized,bilateral eye (lens type), cross-over (care regimen), daily wear, double masked study. Subjects were refitted withsenofilcon A lenses, which were replaced biweekly. During each period of wear, participants used either the peroxideor preserved system. After each period of wear, lenses were collected and lipid was extracted using 1.5 ml of a 2:1chloroform:methanol solution for 3 h at 37°C. Lens extracts were analyzed for non-polar lipids [cholesterol oleate (CO),cholesterol, oleic acid (OA), triolein, and OA methyl ester] using normal phase high-performance liquid chromatography.Results. The total lipid (sum of CO and cholesterol) detected was 34 � 28 �g/lens for the peroxide-based system and 22 �21 �g/lens for the system preserved with Polyquad and Aldox (p � 0.029). Although there was no difference betweenproducts for cholesterol (1.4 vs. 1.3 �g/lens; p � 0.50), use of a system preserved with Polyquad and Aldox resulted insignificantly less deposited CO (33 � 28 vs. 21 � 20 �g/lens; p � 0.033). Approximately, 95% of the detectable lipiddeposited on the material was CO, followed by cholesterol. OA and triolein contributed �1% of the total lipid and noOA methyl ester was found on any of the lenses.Conclusions. A care system preserved with Polyquad and Aldox removed higher amounts of CO from senofilcon Acontact lenses used for 2 weeks than a peroxide-based system, in soft lens wearers who were symptomatic of dry eye.(Optom Vis Sci 2011;88:1172–1179)

Key Words: silicone hydrogel, contact lens, lens care solutions, lipids, cholesterol, dry eye, deposition

Hydrogel contact lenses rapidly sorb components from thetear film, particularly proteins,1–4 lipids,3,5–8 and mu-cins.2,9 At higher levels of build up, these deposits are

associated with altered visual acuity,10 altered lens wettability,11

dryness and discomfort,6,12 increased bacterial adhesion,13–15 lid-related inflammatory changes, and contact lens-associated papil-lary conjunctivitis.16,17–19 Lipid deposits on silicone hydrogel(SH) lens materials have attracted significant interest among re-searchers,9,20 and it is well established that lipid deposition can bean issue with SH contact lens materials.1,3,9,21

About 45 different lipids have been recognized in humanmeibum.22–25 The superficial lipid layer is composed of two dif-ferent lipid phases, with an inner polar-surfactant phase and an

outer non-polar phase.25 The non-polar phase (which contains alarge amount of non-polar lipids, including wax esters, cholesterolesters, triglycerides, and hydrocarbons) is larger than the polarphase, hence non-polar lipids are found in greater quantities.25

There are several factors that influence tear film deposition ontohydrogel contact lenses materials including material composition,water content,26,27 surface charge,4,26,28 pore size of the material,29

hydrophobicity of the material,30 and tear film characteristics.6,31

In addition to the aforementioned factors, lens care solutions also playa vital role in the sorption of tear film lipids on to the contact lenssurface. Modern-day multipurpose cleaning and disinfecting lens careregimens are complex mixtures of components that include a numberof wetting agents, biocides, and surfactants, designed to enhance in-eye wettability and reduce deposition of proteins and lipids on thelens surface.32 Most commercially available systems are eitherbased on preservatives (such as polyquaternium-1 or Polyhexam-ethylene biguranide) or hydrogen peroxide. Hydrogen peroxidesystems tend to be chemically less complex than multipurpose

*MSc†BS(Optom), PhD, FAAO‡PhD, FCOptom, FAAOCentre for Contact Lens Research, School of Optometry, University of Water-

loo, Waterloo, Ontario, Canada.

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Optometry and Vision Science, Vol. 88, No. 10, October 2011

regimens but can contain additional components, including sur-factants. Differences between these two types of regimens mayresult in differences in variations in clinical performance and de-position of tear-film components on to the lenses.

Studies in the literature have quantified lipid deposition on SHcontact lenses through in vitro33,34 and ex vivo models9,20,34–36

using various techniques, including thin-layer chromatography,35

high-performance liquid chromatography (HPLC),9,20 gas chro-matography and mass spectrometry,37 and cholesterol esterase en-zymatic reaction.34 However, little data exists concerning thedifferences in lipid deposition measured ex vivo that occur with SHlenses disinfected with various care regimens.20,35,36 The purposeof this study was to determine if there were differences between acare system preserved with Polyquad and Aldox and a hydrogenperoxide-based lens care regimens with respect to specific ex-vivonon-polar lipid deposits in senofilcon A (Acuvue OASYS, Johnson& Johnson Vision Care, Jacksonville, FL) SH lens wearers report-ing dryness symptoms with their habitual lenses.

METHODS

Approval of this project was granted through the Office of ResearchEthics at the University of Waterloo and all procedures adhered to the

tenets of the Declaration of Helsinki. Participants were recruited at theCentre for Contact Lens Research, School of Optometry. Informedconsent was obtained from all participants, following explanation ofthe purpose of the study and procedures to be undertaken.

This study was conducted as a 4-week prospective, randomized,bilateral eye (lens type), cross-over (lens care regimens), daily wear,double-masked dispensing study (Fig. 1). The study had two phases(phases I and II) and each phase lasted for 2 weeks. A schematic of thestudy design is shown in Fig. 1. Thirty participants (23 F and 7 M)symptomatic of dry eye were enrolled the study. Eligibility was deter-mined based on the criteria shown in Table 1. The mean age of theparticipants was 24.3 years (median 24 years, ranging from 18 to 43years). All were adapted soft lens wearers, wearing their habitual lenseson a daily wear basis for a minimum of 10 h/d (with a bi-weekly ormonthly replacement schedule). By the end of the study, only 26complete pairs of lenses were available for analysis (see later for rea-sons), hence the sample size for final analysis reported in this study was26 per lens care system.

Senofilcon A (Acuvue OASYS, Johnson & Johnson VisionCare) lenses were used in this study (Table 2). The two lens careregimens used in this study were a no-rub one-step hydrogen per-oxide system (ClearCare, CIBA VISION, Atlanta, GA) and a sys-

FIGURE 1.Study design used in this study.

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tem preserved with Polyquad and Aldox (no-rub 5-s rinse) system(OPTI-FREE RepleniSH, Alcon, Fort Worth, TX). Details re-garding these care regimens can be found in Table 3. Participantspreviously using a peroxide-based care system or a system preservedwith Polyquad and Aldox as their habitual lens cleaning solutionswere not included in the study. The investigator and participantswere all masked. All participants had a 2- to 3-day wash-out periodbefore entering each phase of the study (i.e., before each phase’sbaseline visit), during which time spectacles were worn.

Lens care systems were assigned for each study phase accordingto a randomization table. Participants began with one system and

then switched to the other system in the second phase. Subjectswere instructed to wear the study lenses on a daily wear basis for atleast 12 h/d and at least 6 d/week for the duration of the 4-weekstudy. Participants were instructed to clean and disinfect theirlenses, using the appropriate study lens care system, after each dayof lens wear. As far as possible, participants were masked fromwhich care regimen they were using. All identifying labels wereremoved, but it was not possible to mask the embossed “Alcon”from the care system preserved with Polyquad and Aldox. Partici-pants using lubricating drops with their habitual contact lenseswere allowed to continue to use their habitual brand of drops. Theuse of drops was recorded along with the subjective symptomratings throughout the study (not reported here). Study visits werescheduled after at least 4 h of wear and at approximately the sametime for a given study participant in each study phase. At the2-week visit for each phase, the participants were required to returnall remaining study products. The study lenses were collected at theend of each phase (Fig. 1), at which time lenses were stored at�80°C until lipid deposits on the lenses were analyzed.

TABLE 1.Dry eye questionnaire used in this study

Questions for prospective participant

Responses (please circle)

Stronglydisagree Disagree Undecided Agree

Stronglyagree

1. My contact lenses are comfortable all day long.a 1 2 3 4 52. During the day, I take my contact lenses out sooner

than I would like because they become uncomfortable.b1 2 3 4 5

3. Late in the day, my contact lenses become uncomfortable,but I continue wearing them.b

1 2 3 4 5

Participants who answered “Undecided”, “Agree”, or “Strongly Agree” to question 1, regardless of how questions 2 and 3 areanswered, were considered screen failures, and thus were non-eligible for the study. Participants must have also answered questions2 or 3, or both, with “Agree” or “Strongly Agree” to have participated in the study.

aMust answer “strongly disagree” or “disagree” to this question.bMust answer “agree” or “strongly agree” to at least one of these questions.

TABLE 2.Features of senofilcon A contact lenses used in this study atthe time of the study

Proprietary name Acuvue OASYS

USAN Senofilcon AManufacturer J&J Vision CareCenter thickness at

�3.00 D) (mm)0.07

Water content (%) 38%Total diameter (mm) 14.0Back optic zone

radius (mm)8.4

Prescription range (D) �0.50 to �8.00Recommended replacement

schedule1–2 weeks

Oxygen permeability(�10�11)

103

Oxygen transmissibility(�10�9)

147

Surface treatment None (internal wetting agent)FDA group IPrincipal monomersa mPDMS � DMA � HEMA �

siloxane macromer �TEGDMA � PVP

amPDMS, monofunctional polydimethylsiloxane; DMA, N,N-dimethylacrylamide; HEMA, poly-2-hydroxyethyl methacrylate;TEGDMA, tetraethyleneglycol dimethacrylate; and PVP, polyvi-nyl pyrrolidone.

TABLE 3.Lens care regimen used in the study

Commercialname Clear care OPTI-FREE RepleniSH

Manufacturer Cibavision Canada2150 Torquay

Mews,Mississauga L5N

2M6, ON, CA

Alcon Laboratories

Biocide 3% Hydrogenperoxide

0.001% Polyquaternium-1(Polyquad)

0.0005% MAPD (Aldox)Buffer Phosphate-

buffered systemBoric acid

Chelating agent — Citrate (citric acid)Surfactant/

wetting agentsPluronic 17R4

(non-ionic)TearGlyde (Poloxamine

�Tetronic 1304� �nonanoyl ethylene-diaminetriacetic acid�C-9 ED3A�)

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Reagents and Materials

The lipids used for standards were cholesterol, cholesterol oleate(CO), oleic acid (OA), OA methyl ester (OAME), and triolein. Lipidstandards, chloroform, and methanol for extraction solutions were pur-chased from Sigma-Aldrich (Oakville, ON, Canada) and HPLC solventswere purchased from Fisher Scientific (Ottawa, ON, Canada).

Lipid Deposit Extraction From Lenses

Lens Collection and Storage

Study lenses were carefully removed by the investigator, with cleanpowder-free nitrile gloves (SemperCare Nitrile PF) at the end of each2-week phase and stored dry at �80°C in amber glass vials. Lenscollection was randomized, with either the left or right lens beingcollected for lipid analysis. The same randomization was used for bothphases to allow for pair-wise phase comparisons for each participant.

Lipid Extraction From Participant-Worn Lenses

Lipids were extracted from each lens by gentle shaking in 1.5 mlof a 2:1 chloroform:methanol solution at 37°C for 3 h. The ex-tracts were evaporated to dryness under a stream of nitrogen, thensealed and stored at �80°C before resolubilization.

Preparation of Unworn Lenses Used forExtract Controls

To control for detergent carry over and possible polymer extraction,unworn lenses were prepared as follows and extracted in parallel withparticipant-worn lenses. Unworn senofilcon A lenses were prepared bysoaking the lens for 8 h intervals in one of the two study solutions,followed by a 16 h soak in phosphate-buffered saline. The solutionswere replaced 14 times to approximate the number of cleaning cyclesof the participant-worn lenses. At the end of the cleaning cycle, eachlens was soaked in 5 ml of phosphate-buffered saline for 5 min toremove any loosely bound care solution components. The lens wasblotted to remove excess moisture and stored at �80°C.

Extract Resuspension Solvent

Lipid samples and extracts from both patient-worn lenses andunworn lens controls were suspended in mobile phase (100hexane: 0.5 isopropanol: 0.01 acetic acid), sonicated and filteredthrough a Nalgene 4-mm nylon syringe filter (0.2 m pore).

Lipid Standard Curves

The range of standard lipid concentration was from 0.01 to 5g. Lipid standards and lens extract controls were run for every 12participant-worn lenses (Fig. 2).

HPLC Parameters

Lipid samples of 10 l were separated isocratically in a mobile phaseof 100 hexane:0.5 isopropanol:0.01 acetic acid on a Hiasil normalphase silica gel column (4.6 � 150 mm) from Higgins Analytical(Mountain View, CA) using a guard column of the same material.The column temperature was held constant at 25°C, the flow rate setto 1.5 ml/min. Chromatograms were collected at 210 nm (Fig. 3).

Quantity Calculation

The peaks of the chromatograms were analyzed with Chromquest4.2 software. The area under the peak was compared with lipid stan-dards and corrected for the entire extract. Unworn lens extracts had asmall peak that co-eluted with the peak for CO. The area of theappropriate control lens was subtracted from the CO peak and thenquantified. The co-eluted peak was �10% of the average CO peakfrom the care system preserved with Polyquad and Aldox-exposedlenses and �5% from the peroxide-based care system lenses.

Statistical Analysis

Data analysis was conducted using SigmaStat 3.1 (Systat Soft-ware, San Jose, CA). Data were presented as means � SD (unlessotherwise stated) and a significance level of p � 0.05 was used forall analyses. All pair-wise comparisons were made with paired Stu-dent t-tests. Data were analyzed using a one way analysis of vari-ance, and Tukey HSD post hoc comparisons were performed,where applicable. Thirty participants were enrolled in both phasesof the study, totaling a maximum of 60 possible lenses for analysis.Two lenses disinfected with the peroxide-based care system werenot analyzed because they were damaged during wear and had to beredispensed, resulting in less wearing time than was acceptable forthe study. Two lenses cleaned using the care system preserved withPolyquad and Aldox were accidentally put into the same vial by theinvestigator and had to be excluded from analysis. One participantdiscontinued early from the study. Thus, 27 peroxide-based caresystem and 28 samples disinfected using the care system preservedwith Polyquad and Aldox were analyzed. Paired t-test analysiscomparing the two care systems for each participant was per-formed. Only complete pairs could be used for this analysis, hencethe sample size was 26 per system.

RESULTS

Lipid Deposited on the Lens

The mean and standard deviation of the lipids deposited on thelenses are summarized in Table 4. The values are given as micro-gram/lens, along with the ranges (in parentheses) for each lipid.The p values for the paired Student t-tests are also listed. In caseswhere the amount of lipid detected was less than the lower limit ofquantification, only the range of values are presented. In thesecases, most of the lenses did not have detectable lipid. The totallipid values are calculated from the sum of CO and cholesterol.They do not include any values from the other lipids, which weretoo low to accurately quantify and include in this analysis.

Summed Lipid Deposition on Lenses

The values for CO and cholesterol were summed together foreach participant. There was a significant difference determinedbetween the two lens care solutions with respect to CO and cho-lesterol deposition on the senofilcon A lenses (34.1 vs. 21.7 g/lens; p � 0.029), with those lenses disinfected with the care systempreserved with Polyquad and Aldox depositing lower quantities oflipid. Approximately, 95% of the contribution to the total lipidvalue was from CO.

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Cholesterol Oleate and Cholesterol Depositionon Lenses

CO deposition was significantly greater with the peroxide-basedcare system than with the care system preserved with Polyquad andAldox (32.7 vs. 20.5 g; p � 0.033). There was no differencebetween care products (1.4 vs. 1.3 g/lens; p � 0.503) with re-spect to cholesterol deposition.

Oleic Acid Deposition on Lenses

OA was detectable in 14 of the 52 lenses examined (27%). Thelower limit of reliable quantification was 0.5 g/lens. AlthoughOA was detectable in around one quarter of the lenses, one-half ofthese samples did not have sufficient quantities present for accuratedetermination. The values reported are extrapolated from beyondthe standard curve, so are only given as estimates. Eight partici-pants in the peroxide-based care system had OA ranging in values

from about 0.1 to 2.5 g/lens. Six participants in the arm using thecare system preserved with Polyquad and Aldox showed OA be-tween 0.3 and 3.2 g/lens. Of these 14 samples, four participantshad OA in both phases.

Triolein Deposition on Lenses

Triolein was less abundant on lenses than OA and occurredfewer times. It was found on only two lenses in the peroxide-based care system (0.2 to 0.3 g/lens) and twice in the caresystem preserved with Polyquad and Aldox arm (0.3 to 0.6 g/lens). The lower limit of reliably measuring triolein was0.25 g/lens.

Oleic Acid Methyl Ester Deposition on Lenses

None of the lenses analyzed had any measurable OAME. Thelower limit to detect OAME was 0.25 g/lens.

FIGURE 2.Representation of a typical calibration curve for the five lipids. All lines of fit had an r2 correlation of 0.998 or better.

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DISCUSSION

This study reports the deposition of major non-polar lipids on exvivo senofilcon A lenses disinfected with either a care system preservedwith Polyquad and Aldox or a peroxide-based care system, in partici-pants symptomatic of dry eye. This study was able to analyze the majornon-polar lipids that adsorbed to the study lenses. The results fromour study (Table 4) demonstrate that senofilcon A lenses deposit32.7 � 27.9 g/lens of CO with the peroxide-based care system usedin this study (CIBA Vision ClearCare) and 20.5 � 20.1 g/lens whenthe lenses were disinfected with a care system preserved with Polyquadand Aldox (Alcon Opti-Free RepleniSH). To our knowledge, this isthe first ex vivo study to have quantified CO deposited on senofilconA SH contact lens material. An in vitro study by Pucker et al.34 re-ported that galyfilcon and lotrafilcon B lenses deposited 35 g/lens

and 65 g/lens, respectively, after 3 days of incubation in 5.6 mg/mlof CO solution.

It is of interest to note that the care system preserved withPolyquad and Aldox was able to remove more CO, which makesup about 95% of the measured lipids, from senofilcon A lenses,than a peroxide-based care system (Table 4), which may be attrib-utable to the composition of the care systems. The care systempreserved with Polyquad and Aldox contains citrate, which is anegatively charged ion and a sequestering agent, which aids in thepassive removal of protein.38–40 It is possible that citrate may alsoplay a role in the removal of non-polar lipids from a non-surfacemodified SH contact lens material. In addition, the preserved sys-tem contains a complex mixture of surface-active, block copolymeragents that may have helped to remove a greater amount of lipids.

FIGURE 3.Representative HPLC chromatograms (210 nm) of a worn Acuvue Oasys lens extracted with 2 chloroform: 1 methanol (solid line) superimposed witha lipid standards chromatogram (dotted line). The inset expands the first 6 min.

TABLE 4.Summary of lens lipid deposition data (mean � SD)

Clear care OPTI-FREE RepleniSH p

Total lipid (�g/lens) (sum of CO and cholesterol) 34.1 � 28.0 (3.5–121.8) 21.7 � 20.8 (1.2–74.4) 0.029CO (�g/lens) 32.7 � 27.9 (2.0–119.0) 20.5 � 20.1 (0.4–1.4) 0.033Cholesterol (�g/lens) 1.4 � 1.0 (0–3.6) 1.3 � 1.2 (0–4.4) 0.503OA (�g/lens) �LLOQ (0–2.5) �LLOQ (0–3.2) N/ATriolein (�g/lens) �LLOQ (0–0.4) �LLOQ (0–0.8) N/AOAME (�g/lens) None detected None detected N/A

Figures in parentheses represent the range. Paired Student’s t-tests (n � 26) were performed and a p value �0.05 was consideredsignificantly different. Values extrapolated below the lower limit of quantification (�LLOQ) are estimated and not used in any statisticalanalysis.

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Also, the surfactants are different between the two care solutionsand could have different affinities to CO.

This study results are consistent with other ex vivo studies,20,35

which report that cholesterol is more abundant than OA and OAMEon contact lenses. The data from this report shows lower levels of lipidadsorption compared with previous in vitro studies using OASYS orother group I lenses.5,33 The difference is likely explained by the ab-sence of daily cleaning of lenses in an in vitro study. The cholesteroldeposition values for the peroxide-based system in this study (1.4 �1.0 g/lens) were similar to the study (1.2 � 0.4 g/lens) of Zhao etal.35 In addition, the care system preserved with Polyquad and Aldoxalso showed similar levels of cholesterol deposition in these two studies(1.3 � 1.2 g/lens vs. 1.4 � 0.8 g/lens). Another recent study whichinvestigated cholesterol deposition on senofilcon lenses A when usedin a care system with Polyquad- and Aldox-based system showed re-sults similar to this study.41 Saville et al.36 reported higher amounts ofcholesterol deposition on senofilcon A lenses (9.9 � 2.2 g/lens),which is likely due to differences in the techniques used. Saville et al.36

used mass spectrometry, as opposed to the HPLC method describedin this study. Our laboratory has a well-established protocol for theanalysis of lipids using HPLC. HPLC is a sensitive method for assess-ing lipids on contact lenses. It can measure more than one lipid at agiven time point. HPLC also processes the samples in a consistentmanner. Other techniques such as thin-layer chromatography can belabor intensive and the sensitivity and separation properties of thin-layer chromatography are low. Other ex vivo studies on lipid deposi-tion such as those by Maziarz et al.20 and Pucker et al.34 did not studydeposition in senofilcon A and did not use either of the care systemsused in this study.

Deposition of CO on senofilcon A lenses was studied in vitro byPucker et al.42 They found four- to sixfold less CO compared withthis study. These differences can be attributed to the difference inthe extraction procedure used in the studies. There was a slightdifference in extraction solution (1 choloroform: 1 methanol vs. 2chloroform:1 methanol, respectively) and a large difference in ex-traction times (25 s vs. 3 h, respectively).

This study has shown that lens care solutions can have a signif-icant impact on the amount of lipid remaining on lenses afterhabitual care. The care system preserved with Polyquad and Aldoxused in this study (Alcon Opti-Free RepleniSH) removed 37% moreof the most abundant lipid (CO) found on the senofilcon A lens whencompared with a peroxide-based system (CIBA Vision ClearCare).There was no difference between the two care systems for the amountof cholesterol found on the lens. In a previous ex vivo study examininglipid on SH lenses,20 six of eight (75%) of galyfilcon A wearers had noOAME on their lens, when compared with this study in which noOAME was found on any of the worn lenses.

In this study, participants were subjectively categorized as beingsymptomatic of dry eye based on a dry eye questionnaire. Themeibomian gland secretions from the upper and lower lids couldplay a significant role in the amount of lipids deposited on the lensmaterials, and this is worthy of further study. Clinical signs such asmeibomian gland evaluation, tear break-up time assessment, andtear collection for tear lipid analysis will provide valuable informa-tion on the status of lipids and hence its deposition in contact lenswearers. This study only analyzed the major non-polar lipids de-posited on the lenses and further work on analyzing the polar lipidswould provide a complete picture of lipid deposition on SH lenses

and the role of care regimens in their removal. Previous studies inour laboratory have shown that protein deposition on lenses isprimarily driven by lens material water content and ionicity and toa greater extent are not related to subjective differences.31 How-ever, lipid deposition on lenses is related to many factors includingmaterial composition and intersubject differences in tear film com-ponents, blink factors, and environmental factors.31

Previous studies have clearly shown that a hydrophobic lens surfaceis more prone to lipid deposition,1,5,43 and this could potentially resultin increased discomfort and dryness symptoms in contact lens wearers.The results from this study showed that a care system preserved withPolyquad and Aldox removed more non-polar lipids than a peroxide-based care system. Hence, the citrate containing Polyquad and Aldoxcare system may benefit patients who are heavy contact lens lipiddepositors. In this study, Polyquad- and Aldox-based system whenused as a “no rub, 5 s rinse only” format showed significantly loweramounts of lipid deposition. Future studies using Polyquad and Aldoxsystem in a rub and rinse format may show a further reduction in theamounts of lipids deposited on to the lenses.

In conclusion, a care system preserved with Polyquad and Aldoxremoved more non-polar lipids from senofilcon A lenses than dida peroxide-based care system in a 2-week, cross-over study. Ap-proximately, 95% of the measured lipid was CO, with cholesterolmaking up most of the rest. OA and triolein contributed �1% andno OAME was found on any of the lenses.

ACKNOWLEDGMENTS

This study was sponsored by ALCON Research Ltd.Received January 20, 2011; accepted May 27, 2011.

REFERENCES

1. Bontempo AR, Rapp J. Protein and lipid deposition onto hydrophiliccontact lenses in vivo. CLAO J 2001;27:75–80.

2. Castillo EJ, Koenig JL, Anderson JM, Jentoft N. Protein adsorptionon soft contact lenses. III. Mucin. Biomaterials 1986;7:9–16.

3. Jones L, Evans K, Sariri R, Franklin V, Tighe B. Lipid and proteindeposition of N-vinyl pyrrolidone-containing group II and group IVfrequent replacement contact lenses. CLAO J 1997;23:122–6.

4. Sack RA, Jones B, Antignani A, Libow R, Harvey H. Specificity andbiological activity of the protein deposited on the hydrogel surface.Relationship of polymer structure to biofilm formation. Invest Oph-thalmol Vis Sci 1987;28:842–9.

5. Bontempo AR, Rapp J. Protein-lipid interaction on the surface of ahydrophilic contact lens in vitro. Curr Eye Res 1997;16:776–81.

6. Jones L, Franklin V, Evans K, Sariri R, Tighe B. Spoilation andclinical performance of monthly vs. three monthly group II dispos-able contact lenses. Optom Vis Sci 1996;73:16–21.

7. Maissa C, Franklin V, Guillon M, Tighe B. Influence of contact lensmaterial surface characteristics and replacement frequency on proteinand lipid deposition. Optom Vis Sci 1998;75:697–705.

8. Rapp J, Broich JR. Lipid deposits on worn soft contact lenses. CLAOJ 1984;10:235–9.

9. Jones L, Senchyna M, Glasier MA, Schickler J, Forbes I, Louie D,May C. Lysozyme and lipid deposition on silicone hydrogel contactlens materials. Eye Contact Lens 2003;29:S75–9.

10. Gellatly KW, Brennan NA, Efron N. Visual decrement with depositaccumulation of HEMA contact lenses. Am J Optom Physiol Opt1988;65:937–41.

1178 Non-Polar Lipid Deposits on Senofilcon A Contact Lenses—Heynen et al.

Optometry and Vision Science, Vol. 88, No. 10, October 2011

11. Lorentz H, Rogers R, Jones L. The impact of lipid on contact anglewettability. Optom Vis Sci 2007;84:946–53.

12. Fonn D, Dumbleton K. Dryness and discomfort with silicone hydro-gel contact lenses. Eye Contact Lens 2003;29:S101–4.

13. Aswad MI, John T, Barza M, Kenyon K, Baum J. Bacterial adherence toextended wear soft contact lenses. Ophthalmology 1990;97:296–302.

14. Butrus SI, Klotz SA. Contact lens surface deposits increase the adhe-sion of Pseudomonas aeruginosa. Curr Eye Res 1990;9:717–24.

15. Taylor RL, Willcox MD, Williams TJ, Verran J. Modulation of bac-terial adhesion to hydrogel contact lenses by albumin. Optom Vis Sci1998;75:23–9.

16. Allansmith MR, Korb DR, Greiner JV, Henriquez AS, Simon MA,Finnemore VM. Giant papillary conjunctivitis in contact lens wear-ers. Am J Ophthalmol 1977;83:697–708.

17. Porazinski AD, Donshik PC. Giant papillary conjunctivitis in fre-quent replacement contact lens wearers: a retrospective study. CLAOJ 1999;25:142–7.

18. Skotnitsky C, Sankaridurg PR, Sweeney DF, Holden BA. Generaland local contact lens induced papillary conjunctivitis (CLPC). ClinExp Optom 2002;85:193–7.

19. Skotnitsky CC, Naduvilath TJ, Sweeney DF, Sankaridurg PR. Twopresentations of contact lens-induced papillary conjunctivitis(CLPC) in hydrogel lens wear: local and general. Optom Vis Sci2006;83:27–36.

20. Maziarz EP, Stachowski MJ, Liu XM, Mosack L, Davis A, MusanteC, Heckathorn D. Lipid deposition on silicone hydrogel lenses, partI: quantification of oleic acid, oleic acid methyl ester, and cholesterol.Eye Contact Lens 2006;32:300–7.

21. Hart DE, Tidsale RR, Sack RA. Origin and composition of lipiddeposits on soft contact lenses. Ophthalmology 1986;93:495–503.

22. Greiner JV, Glonek T, Korb DR, Booth R, Leahy CD. Phospholipidsin meibomian gland secretion. Ophthalmic Res 1996;28:44–9.

23. Greiner JV, Glonek T, Korb DR, Leahy CD. Meibomian gland phos-pholipids. Curr Eye Res 1996;15:371–5.

24. Shine WE, McCulley JP. Polar lipids in human meibomian glandsecretions. Curr Eye Res 2003;26:89–94.

25. McCulley JP, Shine W. A compositional based model for the tear filmlipid layer. Trans Am Ophthalmol Soc 1997;95:79–88.

26. Minarik L, Rapp J. Protein deposits on individual hydrophilic con-tact lenses: effects of water and ionicity. CLAO J 1989;15:185–8.

27. Fowler SA, Korb DR, Allansmith MR. Deposits on soft contact lensesof various water contents. CLAO J 1985;11:124–7.

28. Minno GE, Eckel L, Groemminger S, Minno B, Wrzosek T. Quan-titative analysis of protein deposits on hydrophilic soft contact lenses:I. Comparison to visual methods of analysis. II. Deposit variationamong FDA lens material groups. Optom Vis Sci 1991;68:865–72.

29. Garrett Q, Laycock B, Garrett RW. Hydrogel lens monomer constit-uents modulate protein sorption. Invest Ophthalmol Vis Sci 2000;41:1687–95.

30. Bohnert JL, Horbett TA, Ratner BD, Royce FH. Adsorption of pro-teins from artificial tear solutions to contact lens materials. InvestOphthalmol Vis Sci 1988;29:362–73.

31. Jones L, Mann A, Evans K, Franklin V, Tighe B. An in vivo comparisonof the kinetics of protein and lipid deposition on group II and group IVfrequent-replacement contact lenses. Optom Vis Sci 2000;77:503–10.

32. Jones L, Senchyna M. Soft contact lens solutions review. Part 1:components of modern care regimens. Optom Pract 2007;8:45–56.

33. Carney FP, Nash WL, Sentell KB. The adsorption of major tear filmlipids in vitro to various silicone hydrogels over time. Invest Ophthal-mol Vis Sci 2008;49:120–4.

34. Pucker AD, Thangavelu M, Nichols JJ. Enzymatic quantification ofcholesterol and cholesterol esters from silicone hydrogel contactlenses. Invest Ophthalmol Vis Sci 2010;51:2949–54.

35. Zhao Z, Carnt NA, Aliwarga Y, Wei X, Naduvilath T, Garrett Q, KorthJ, Willcox MD. Care regimen and lens material influence on siliconehydrogel contact lens deposition. Optom Vis Sci 2009;86:251–9.

36. Saville JT, Zhao Z, Willcox MD, Blanksby SJ, Mitchell TW. Detec-tion and quantification of tear phospholipids and cholesterol in con-tact lens deposits: the effect of contact lens material and lens caresolution. Invest Ophthalmol Vis Sci 2010;51:2843–51.

37. Iwata M, Ohno S, Kawai T, Ichijima H, Cavanagh HD. In vitroevaluation of lipids adsorbed on silicone hydrogel contact lenses usinga new gas chromatography/mass spectrometry analytical method. EyeContact Lens 2008;34:272–80.

38. Christensen B, Lebow K, White EM, Cedrone R, Bevington R. Ef-fectiveness of citrate-containing lens care regimens: a controlled clin-ical comparison. Int Contact Lens Clin 1998;25:50–8.

39. Hong B, Bilbaut T, Chowhan M, Keith D, Quintana R, Turner F,Van Duzee B. Cleaning capability of citrate-containing versus non-citrate contact lens cleaning solutions: an in vitro comparative study.Int Contact Lens Clin 1994;21:237–40.

40. Simmons PA, Ridder WH, III, Edrington TB, Ho S, Lau KC. Passiveprotein removal by two multipurpose lens solutions: comparison ofeffects on in vitro deposited and patient worn hydrogel contact lenses.Int Contact Lens Clin 1999;26:33–8.

41. Omali NB, Zhu H, Zhao Z, Ozkan J, Xu B, Borazjani R, WillcoxMD. Effect of cholesterol deposition on bacterial adhesion to contactlenses. Optom Vis Sci 2011;88. (e-pub ahead of print).

42. Pucker AD, Thangavelu M, Nichols JJ. In vitro lipid deposition onhydrogel and silicone hydrogel contact lenses. Invest Ophthalmol VisSci 2010;51:6334–40.

43. Bontempo AR, Rapp J. Lipid deposits on hydrophilic and rigid gaspermeable contact lenses. CLAO J 1994;20:242–5.

Sruthi SrinivasanCentre for Contact Lens Research

School of OptometryUniversity of Waterloo200 University Ave W

Waterloo, Ontario N2L3G1Canada

e-mail: s2sriniv@uwaterloo.ca

Non-Polar Lipid Deposits on Senofilcon A Contact Lenses—Heynen et al. 1179

Optometry and Vision Science, Vol. 88, No. 10, October 2011