S18 Abstracts of the 2011 BCLA Annual Clinical Conference / Contact Lens & Anterior Eye 34, Supplement 1 (2011) S1–S43

tients with KCS and the method is applicable as an examiner-independent,non-invasive analysis of tear film in clinical use.

7

Novel tear films supplements: a potential application for syntheticprotein-phospholipid complexes

Darren Campbell*, Anisa Mahomed, Nadia Rasul, Marc P Broadbent, Brian JTighe

Aston University, Birmingham, UK

*E-mail address: d.campbell1@aston.ac.uk

Purpose: Surfactant proteins A, B, C and D complex with (phospho)lipids toproduce surfactants which provide low interfacial tensions. It is likely thatsimilar complexation occurs in the tear film and contributes to its low sur-face tension. Synthetic protein-phospholipid complexes, with styrenemaleicanhydrides (SMAs) as the protein analogue, have been shown to have simi-larly low surface tensions. This study investigates the potential of modifiedSMAs and/or SMA-phospholipid complexes, which form under physiologicalconditions, to supplement natural tear film surfactants.

Method: SMAs were modified to provide structural variants which canform complexes under varying conditions. Infrared spectroscopy and Nu-clear Magnetic Resonance were used to confirm SMA structure. Interfacialbehaviour of the SMA and SMA-phospholipid complexes was studied usingLangmuir trough, du Nûoy ring and pulsating bubblemethods. Factors whichaffect SMA-phospholipid complex formation, such as temperature and pH,were also investigated.

Results: Structural manipulation of SMAs allows control over com-plex formation, including under physiological conditions (e.g. partial SMA-esterfication allowed complexation with dimyristoylphosphatidylcholine, atpH7). The low surface tensions of the SMAs (42mN/m for static (du Nûoyring) and 34mN/m for dynamic (Langmuir) techniques) demonstrate theirsurface activity at the air-aqueous interface. SMA-phospholipid complexesprovide even lower surface tensions (∼2 mN/m), approaching that of lungsurfactant, as measured by the pulsating bubble method.

Conclusions: Design of the molecular architecture of SMAs allows controlover their surfactant properties. These SMAs could be used as novel tear filmssupplements, either alone to complex with native tear film phospholipids ordelivered as synthetic protein-phospholipid complexes.

8

Tear film osmolarity changes with different eye drops

Giancarlo Montani

Università del Salento FCM, Lecce, Italy

E-mail address:montani.gc@libero.it

Purpose: Check osmolarity of the tear film (TFO) using two different eyedrops, containing: polyethylene glycol 400, 2.5% and sodium hyaluronate(Blink Intensive Tears, Abbott Medical Optics); Sodium carboxymethylcel-lulose 0.5% and Glycerine 0.9% (Optive Eye Drops Allergan).

Method: 20 subjects involved, aged between 21 and 58 with dry eye feel-ing. Dry eye symptoms evaluated with OSDI questionnaire with an averagescore of 42±5. TFO was measured with TearLab (TearLab Corporation) be-fore and after 30, 60, 90, 120 and 180minutes from the instillation of 2 dropsof Blink Intensive Tears™ (BIT) in the right eye 2 drops of Optive Eye Drops(OED) in the left eye. This treatment, repeated three times a day, was fol-lowed for 21 days. TFO was measured again after the patients stopped to usethe eye drops one day and after 6 hours from the waking up.

Results: Baseline TFO were 328.57±11.31 for RE and 327.86±9 for LE.After 180 minutes from the instillation the TFO were 307±15.02 for REand 320.77±15.63 and the difference from the starting point significant(p<0.05). TFO after 21 days were 307.14±10 for RE and 314.29±12.3 andthe difference from the starting point significant (p<0.05).

Conclusions: BIT and OED reduce the tear osmolarity in a period of timeof 180min from the instillation and after 21 days of use with more reductionwith BIT.

9 Dallos Award Winner

Lid wiper epitheliopathy: exploring the links to comfort and osmolalityin contact lens wear

Ulrike G Stahl*, Androniki Delaveris, Michele Madigan, Isabelle Jalbert

School of Optometry and Vision Science, University of New South Wales,Sydney, Australia

*E-mail address: u.stahl@unsw.edu.au

Purpose: Explore the relationship between osmolality, comfort and lid wiperepitheliopathy (LWE) in contact lens wear. Firstly, techniques for LWE de-tection were tested by assessing the repeatability of LWE, the effectivenessof various lissamine green (LG) strips, and the effect of lid eversion on LWE.

Method: 22 subjects participated in a study testing four LG strips withone strip being tested twice. Effects of single versus double instillation andlid eversion on LWEwere tested using ten participants. Twenty subjects par-ticipated in a cross-over study where lenses A and B were worn. Tear andcontact lens osmolality, comfort and LWE were measured. Studies were ran-domised and masked.

Results: There were no differences in day to day LWE (p>0.05), but fre-quencies and intensities of LWE differed between different strips (p<0.05).LWE increased using dual lid eversion (p<0.05) but not dual instillation.Comfort (Lens A 77±24, B 79±23; p>0.05), tear osmolarity (Lens A 300±15,B 293±10 mmol/L; p>0.05) and contact lens osmolality (A 380±90, B351±58mmol/kg; p>0.05) were not affected by lens type. High proportionsof LWE were observed at the upper (no lens 65%, A 85%, B 80%; p>0.05) andlower (no lens 90%, A 100%, B 90%; p>0.05) lid margins.

Conclusions: Although LWE is repeatable, strip type and lid eversion needto be carefully controlled. A relationship between tear or lens osmolality,comfort and LWE at the upper lid margins was not demonstrated.

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Effect of contact lens wear on tear osmolarity in a normal population

Assumpta Peral*, Carmen Dominguez-Godinez, Gonzalo Carracedo, GemaMartinez-Florentin

University Complutense of Madrid, Madrid, Spain

*E-mail address: assumpta@opt.ucm.es

Purpose: The purpose of this study was to establish whether contact lenswear was able to modify the osmolarity in the tear film of healthy individu-als.

Methods: 11 subjects with a baseline tear osmolarity (< 308 mOsms/L),ages 19–23, were selected as first time lens wearers. Silicone hydrogel con-tact lenses “Biofinity™” were used following screening; tear film osmolaritywas measured “TearLab Osmolarity System” 30 minutes before insertion, 2hours after insertion, 8 hours after insertion and 1 hour after removal. Thesecond and third measurements were made with lenses in the eye. Subjectswere evaluated one day, one week, and four weeks after screening. Drynessand discomfort sensations were measured by VAS (0–10) before osmolaritymeasurements.

Results: No significant changes were seen between baseline (297.7±10.4mOsms/L), 2 hours (296.6±11.6 mOsms/L), or 8 hours after insertion(296.9±11.7 mOsms/L). Tear osmolarity was slightly lower than baseline 1hour after removal (293.1±12.3 mOsms/L, p=0.003), but the difference wasnot statistically significant. No significant trends were seen over time. Threesubjects showed brief excursions between 316–323mOsms/L following lensuse. The VAS values for discomfort were in a range between 2.7±1.9 and0.7±0.6 and for dryness were between 2.5±2.8 and 0.6±0.5.

Conclusions: Osmolarity measurements remain stable with contact lenswear in neophytes with good tear films.