Based on kinematic properties and distinct substrates, there are different classes of eyelid movement described as eyeblinks. We investigate whether the eyelid movements made in response to a conditioned stimulus (CS) are a category of eyelid movements distinct from blinks. Human subjects received 60 trials of classical eyelid conditioning with a tone as the CS and electrical stimulation of the supraorbital branch of the trigeminal nerve as the unconditioned stimulus (UCS). Before and after training, reflex blinks were elicited with the UCS. The kinematics of conditioned responses (CRs) differed significantly from those of reflex blinks. The slope of the amplitude-maximum velocity function was steeper for reflex blinks than for CRs, and reflex blink duration was significantly shorter than CR duration. Unlike reflex blinks, for which maximum velocity was independent of blink duration, the maximum velocity of CRs depended on CR duration. These quantitative and qualitative differences indicated that CRs were a unique class of eyelid movements distinct from blinks and eyelid movements with vertical saccadic gaze shifts.
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http://dx.doi.org/10.1152/jn.00631.2009 | DOI Listing |
J Clin Med
December 2024
Plastic Surgery Unit, University Hospital Trust of Sassari, 07100 Sassari, Italy.
Involutional lower eyelid ectropion is a common disorder of the elderly population. Several surgical approaches have been described in the literature to address the multifactorial nature of this condition, each targeting different factors contributing to its development. Nevertheless, no single procedure has proven to be superior to the others.
View Article and Find Full Text PDFEye Contact Lens
December 2024
Department of Ophthalmology (E.D., Z.B.S., E.E.E.O., H.O.), Istanbul Medeniyet University Goztepe Prof. Dr. Suleyman Yalçin City Hospital, Istanbul, Turkey; Goztepe Prof. Dr. Suleyman Yalçin City Hospital (O.F.Y.), Department of Ophthalmology, Istanbul, Turkey; and Haydarpasa Numune Education and Research Hospital (M.S.M.), University of Health Sciences, Sadik Eratik Eye Institute, Istanbul, Turkey.
Objectives: This study compares the cosmetic and functional outcomes of corneal tattooing/keratopigmentation and ocular prostheses in rehabilitating disfigured eyes, focusing on esthetic appearance and emotional well-being.
Methods: Ninety-two patients were included: 48 received corneal tattooing, and 44 were fitted with ocular prostheses. Anophthalmic surgery was indicated for trauma, painful blind eye, endophthalmitis, tumor, and corneal ulcer, while corneal tattooing was performed for trauma, corneal ulcer, and endophthalmitis.
Cureus
November 2024
Department of Ophthalmology, College of Medicine, University of Bisha, Bisha, SAU.
Stilling-Duane syndrome, a congenital condition characterized by aberrant innervation of the lateral rectus muscle and agenesis of the abducent nerve or its nucleus, results in limited horizontal eye movements. It is often misdiagnosed as acquired abducent nerve paralysis. This report highlights the importance of considering Stilling-Duane syndrome in differential diagnoses.
View Article and Find Full Text PDFOphthalmic Plast Reconstr Surg
December 2024
Division of Oculofacial Plastic and Reconstructive Surgery, Shiley Eye Institute, UCSD, La Jolla, California, U.S.A.
Purpose: To describe and characterize shortened fornix syndrome (SFS), a rare complication following posterior-approach ptosis repair using conjunctival Müller muscle resection.
Methods: This retrospective case series evaluates 4 patients who developed SFS after conjunctival Müller muscle resection. Clinical characteristics, surgical histories, management, and outcomes are reviewed.
J Vis
December 2024
Department of Psychology, Graduate School of Humanities, Chiba University, Chiba, Japan.
The fact that blinks occur more often than necessary for ocular lubrication has led to the proposal that blinks are involved in altering some aspects of visual cognition. Previous studies have suggested that blinking can modulate the alternation of different visual interpretations of the same stimulus, that is, perceptual alternation in multistable perception. This study investigated whether and how different types of blinks, spontaneous and voluntary, interact with perceptual alternation in a multistable perception paradigm called continuous flash suppression.
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