• Conference proceedings Dutch Contact Lens Conference 2014.

• Subject: Extended wear tear film secrets page 87.

• Several small studies show a diurnal change in tear film composition. There appears to be a substantial increase in secretory immunoglobulin A concentration after a night’s sleep. Additionally, activated complement has been reported. These findings have led to the hypothesis of a physiological nocturnal inflammatory state of the tear film. Contact lens extended or closed eye wear gained popularity due to the introduction of silicone hydrogel materials and orthokeratology. Unfortunately, we still don’t understand the pathways that lead to deposition and the role of deposition in inflammatory processes. Therefore I strongly recommend further research in this area.

Extended Wear Tear Film Secrets

Maurice M.T.H. Heunen, MSc

Director Optometrisch Centrum Oud Geleen

Acknowledgements

Supervised by prof. Judith Morris, MSc

Overnight Contact Lens Wear

• Hydrogel• Silicone Rubber• Orthokeratology• Silicone Hydrogel

Protein Extraction Effectiveness

Method Protein extracted from Lotrafilcon B (µg/lens)

TFA/ACN 8.04 ± 3.75

Urea 3.29 ± 2.32

Acetone 2.06 ± 1.15

TCA 0.31 ± 0.23

Powell et al., Lipophilic versus hydrodynamic modes of uptake and release by contact lenses of active entities used in multipurpose solutions, CLAE, 2009

Extraction efficiency of TFA/ACN

Extraction efficiency in % for TFA/ACN for Albumin

Lens Material

73.5 ± 5.6 Lotrafilcon B

91.5 ± 3.4 Galyfilcon A

81.5 ± 5.8 Balafilcon A

Subbaraman et al., Efficacy of an Extraction Solvent used to Quantify Albumin deposition on Hydrogel Contact Lens Materials, Eye & Contact Lens, 2009

Protein (µg/lens)

0

5

10

15

20

25

30

35

1.5 ml 50:500.2% TFA/ACN

1.5 ml 50:500.02% TFA/ACN

4M urea

lotrafilcon Alotrafilcon BBalafilcon AGalyfilcon ASenofilcon A

Dr Barr’s Hypothesis (1989)

• Not the amount of protein, but the state of the protein elicits inflammatory responses.

Barr et al., Protein and Elemental Analysis of Contact Lenses of Patients with SLK or GPC, Optometry and Vision Science, 1989

Lysozyme activity

Active protein Reference

Etafilcon >94% Subbaraman et al., Protein Deposition and Symptoms with Daily Wear Etafilcon Lenses, OVS, 2012

Balafilcon A approximate 50%

Luensmann & Jones, Protein deposition on contact lenses CLAE, 2012

Lotrafilcon A+B ≤25% Luensmann & Jones, Protein deposition on contact lenses CLAE, 2012

Lipids on Silicone Hydrogels

Problem:

Wide variety of extraction chemicals and methodology.

Pucker et al., In Vitro Lipid Deposition on Hydrogel and Silicone Hydrogel Contact Lenses, IOVS, 2010

Hatou et al., Biochemical analyses of lipids deposited on silicone hydrogel lenses, Journal of Optometry, 2010

Lipids on Silicone HydrogelsKey Points:•Majority cholesterol deposits•Little bit polar phospholipids•Care systems might play a role•Deposit formation pathways remain unknown

Hatou et al., Biochemical analyses of lipids deposited on silicone hydrogel lenses, Journal of Optometry, 2010

Heynen et al., Quantification of Non-Polar Lipid Deposits in Senofilcon A Contact Lenses, OVS, 2011

Gipson, The Ocular Surface: The Challenge to Enable and Protect Vision, IOVS, 2007

Closed eye sub inflammatory?

Increase in IgA concentration

(closed eye)

BUT

N=6

No p-value

Sack et al., IOVS, 1992

Secret unveiled:Primary active defence agent changes

Lysozyme secretory Immunoglobulin A

Lysozyme

• Enzyme that attacks the cell wall of some bacteria (especially Gram+)

Immunoglubulin or Antibody

• Soluble proteins secreted by activated B cells or by plasma cells in response to an antigen.

• Recognises antigen & initiates complement fixation and opsonisation.

Closed eye sub inflammatory?

Higher presence of complement C3 and Factor B (closed eye)

BUT

N=8

No p-value

Willcox et al., IOVS, 1997

Closed eye sub inflammatory?

Increase in IgA concentration upon waking by 9-fold ANOVA p=0.005

Increase in albumin concentration upon waking by 9-fold ANOVA p=0.006

BUT

N=9

Pooled R+L eye samples

Markoulli et al., OVS 2012

Conclusions

• SiHy’s might have relatively more deposited denatured proteins than traditional hydrogels.

• Deposits might elicit inflammation, but its pathways remain unclear.

• The closed eye tear film may have a sub inflammatory state.

Thank You

info@ocog.nl

Questions?