A new perspective on spontaneous blinks.

PURPOSE To investigate whether the central portions of the upper and lower eyelid margins make complete contact during spontaneous blinks. DESIGN A prospective case series of subjects located in Weinheim, Germany. PARTICIPANTS Data were analyzed from 30 subjects (14 women; mean age, 42.4 ± 12.3 years). METHODS A small drop of lissamine green (LG; 0.15 μl) was placed on the keratinized portion of the central lower lid. Spontaneous blinks were recorded by video from a frontal view and simultaneously from a temporal-inferior view (high-speed video). Blinks were analyzed as being complete or incomplete, and the number of blinks necessary to remove the LG was counted. The upper eyelid was observed to grade the extent of misalignment of the lids in the z-axis. This so-called overblinking of the lids was classified using a 5-grade scale (0 = aligned; 1 = less than one-third overblink; 2 = more than one-third to two-thirds overblink; 3 = more than two-thirds to three-thirds overblink; and 4 = more than three-thirds overblink). Correlations were calculated by Pearson correlation (or Spearman rank in nonparametric data), and differences between groups were calculated by unpaired t test (or Mann-Whitney U test in nonparametric data). MAIN OUTCOME MEASURES Contact between lids in spontaneous blinks and lid alignment. RESULTS Mean blink rate was 14.9 ± 14.1 blinks/minute, and 58.8 ± 22.6% of blinks were incomplete. Blink rate was significantly higher in women than in men (P = 0.007, unpaired t test; female, 22.0 ± 16.8 blinks/minute; male, 8.6 ± 7.2 blinks/minute). Incomplete blinking occurred significantly less often in women (51.2 ± 18.5%) than in men (67.4 ± 24.5%; P = 0.029) but was not related to age (Pearson r = 0.108; P = 0.285). Lissamine green stayed unaltered in spontaneous blinks and, on average, 1.5 ± 0.8 forced blinks were needed to remove the LG. Mean grade of upper lid overblink was 3.0 ± 0.9. Lid overblink was correlated significantly with age (r = 0.456; P = 0.006). CONCLUSIONS Central lid margins do not touch in spontaneous blinks because the lids are not aligned. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

[1]  L. Carney,et al.  THE NATURE OF NORMAL BLINKING PATTERNS , 1982, Acta ophthalmologica.

[2]  D R Korb,et al.  Effect of Periocular Humidity on the Tear Film Lipid Layer , 1996, Cornea.

[3]  E. Gaffney,et al.  A solute gradient in the tear meniscus. II. Implications for lid margin disease, including meibomian gland dysfunction. , 2011, The ocular surface.

[4]  Videonystagmography to assess blinking , 2007, Graefe's Archive for Clinical and Experimental Ophthalmology.

[5]  D. Korb,et al.  Evidence Suggesting That the Keratinized Portions of the Upper and Lower Lid Margins Do Not Make Complete Contact During Deliberate Blinking , 2013, Cornea.

[6]  E. Marx.  Über vitale Färbungen am Auge und an den Lidern , 1924, Albrecht von Graefe's Archiv fur Ophthalmologie.

[7]  D. Garcia,et al.  Spontaneous eyeblink activity. , 2011, The ocular surface.

[8]  E. Knop,et al.  [Meibomian glands. Part I: anatomy, embryology and histology of the Meibomian glands]. , 2009, Der Ophthalmologe : Zeitschrift der Deutschen Ophthalmologischen Gesellschaft.

[9]  Stefan Arnold,et al.  Simultaneous examination of tear film break-up and the lipid layer of the human eye: a novel sensor design (Part 1). , 2010, Zeitschrift fur medizinische Physik.

[10]  A Sprenger,et al.  Effects of voluntary blinks on saccades, vergence eye movements, and saccade-vergence interactions in humans. , 2002, Journal of neurophysiology.

[11]  C. McMonnies.  Incomplete blinking: exposure keratopathy, lid wiper epitheliopathy, dry eye, refractive surgery, and dry contact lenses. , 2007, Contact lens & anterior eye : the journal of the British Contact Lens Association.

[12]  Yutaka Mizukusa,et al.  Rheology of tear film lipid layer spread in normal and aqueous tear-deficient dry eyes. , 2008, Investigative ophthalmology & visual science.

[13]  E. Marx.  Über vitale Färbungen des Auges und der Augenlider , 1926, Albrecht von Graefes Archiv für Ophthalmologie.

[14]  Jason J Nichols,et al.  Evaluation of Tear Film Interference Patterns and Measures of Tear Break-Up Time , 2002, Optometry and vision science : official publication of the American Academy of Optometry.

[15]  M. Doane.  Blinking and the mechanics of the lacrimal drainage system. , 1981, Ophthalmology.

[16]  A. Bron,et al.  The Meibomian Glands and Tear Film Lipids , 1998 .

[17]  P. King-Smith,et al.  The contribution of lipid layer movement to tear film thinning and breakup. , 2009, Investigative ophthalmology & visual science.

[18]  M. Abelson,et al.  A tentative mechanism for inferior punctate keratopathy. , 1977, American journal of ophthalmology.

[19]  Charles Bell,et al.  On the Motions of the Eye, in Illustration of the Uses of the Muscles and Nerves of the Orbit , 1815 .

[20]  D. Curnow,et al.  MEIBOMIAN GLANDS* , 2022 .

[21]  D. Korb,et al.  About Vital Staining of the Eye and Eyelids. I. The Anatomy, Physiology, and Pathology of the Eyelid Margins and the Lacrimal Puncta by E. Marx , 2010, Optometry and vision science : official publication of the American Academy of Optometry.

[23]  E. T. Fuller,et al.  Tear film lipid layer thickness and ocular comfort after meibomian therapy via latent heat with a novel device in normal subjects , 2005, Eye.

[24]  M. Guillon,et al.  Preocular Tear Film Characteristics of Nonwearers and Soft Contact Lens Wearers , 1997, Optometry and vision science : official publication of the American Academy of Optometry.

[25]  A J Bron,et al.  Functional aspects of the tear film lipid layer. , 2004, Experimental eye research.

[26]  J. Lawrenson,et al.  Touch sensitivity of the eyelid margin and palpebral conjunctiva , 1994, Acta ophthalmologica.

[27]  Igor A Butovich,et al.  Lipidomics of human Meibomian gland secretions: Chemistry, biophysics, and physiological role of Meibomian lipids. , 2011, Progress in lipid research.

[28]  K. Nakamori,et al.  Blinking is controlled primarily by ocular surface conditions. , 1997, American journal of ophthalmology.

[29]  M. Doane.  Interactions of eyelids and tears in corneal wetting and the dynamics of the normal human eyeblink. , 1980, American journal of ophthalmology.

[30]  D. R. Iskander,et al.  Blinking Patterns and Corneal Staining , 2006, Eye & contact lens.

[31]  L. Subbaraman,et al.  Clinical manifestations of upper lid staining in adapted silicone hydrogel lens wearers , 2006 .

[32]  A Bradley,et al.  Optical and visual impact of tear break-up in human eyes. , 2000, Investigative ophthalmology & visual science.

[33]  D. Korb,et al.  Meibomian Gland Diagnostic Expressibility: Correlation With Dry Eye Symptoms and Gland Location , 2008, Cornea.

[34]  P. King-Smith,et al.  Interferometric imaging of the full thickness of the precorneal tear film. , 2006, Journal of the Optical Society of America. A, Optics, image science, and vision.