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Objective: The mixed orbicularis oculi muscle lacks an intramuscular proprioceptive system such as muscle spindles, to induce reflex contraction of its slow-twitch fibers. We evaluated whether the mechanoreceptors in Müller's muscle function as extrinsic mechanoreceptors to induce reflex contraction of the slow-twitch fibers of the orbicularis oculi in addition to those of the levator and frontalis muscles. Methods: We evaluated in patients with aponeurosis-disinserted blepharoptosis whether strong stretching of the mechanoreceptors in Müller's muscle from upgaze with unilateral lid load induced reflex contraction of the orbicularis oculi slow-twitch fibers and whether anesthesia of Müller's muscle precluded the contraction. We compared the electromyographic responses of the bilateral orbicularis oculi muscles to unilateral intraoperative direct stimulation of the trigeminal proprioceptive nerve with those to unilateral transcutaneous electrical stimulation of the supraorbital nerve. Results: Upgaze with a unilateral 3-g lid load induced reflex contraction of the bilateral orbicularis oculi muscles with ipsilateral dominance. Anesthesia of Müller's muscle precluded the reflex contraction. The orbicularis oculi reflex evoked by stimulation of the trigeminal proprioceptive nerve differed from that by electrical stimulation of the supraorbital nerve in terms of the intensity of current required to induce the reflex, the absence of R1, and duration. Conclusions: The mechanoreceptors in Müller's muscle functions as an extramuscular proprioceptive system to induce reflex contraction of the orbital orbicularis oculi slow-twitch fibers. Whereas reflex contraction of the pretarsal orbicularis fast-twitch fibers functions in spontaneous or reflex blinking, that of the orbital orbicularis oculi slow-twitch fibers may factor in grimacing and blepharospasm.

Objective: We present a very rare case of penetrating injury into the orbit by a needlefish. The patient underwent extirpation twice at another hospital. Methods: We performed foreign body removal from a right subbrow incision under general anesthesia. Results: The foreign body was successfully removed and the patient's diplopia recovered gradually after surgery. Conclusions: Treatment was similar to that used for penetrating injury. As there is a risk of secondary infection, it is important to completely remove the fish body, followed by vigorous irrigation and debridement.

Objective: Anthropological studies divided the Japanese into the Yayoi migrants, who had narrow eye, no visible superior palpebral crease, and high-positioned round supraorbital margins for cold tolerance, and the Jomon natives, who had wide eye, visible superior palpebral crease, and low-positioned straight supraorbital margins, thus suggesting an anatomical discrepancy between the vertical palpebral fissure and the height of the supraorbital margin. Because Japanese subjects without visible superior palpebral crease open their eyelids by lifting the eyebrows with the anterior lamella owing to increased tonic contraction of the frontalis muscle, we hypothesized that persistently lifting the eyebrows in primary gaze mechanically remodels the supraorbital margin to be high positioned and round. Method: We evaluated whether subjects without visible superior palpebral crease persistently lifted their eyelids more than subjects with visible superior palpebral crease, whether the presence of persistently lifted eyebrow in primary gaze affected the relative height of the supraorbital margin in coronal view 3-dimensional computed tomography imaging, and whether the shape of the supraorbital margin in the coronal view affected that in the sagittal view 3-dimensional computed tomography imaging. Results: Eyebrow height in subjects without visible superior palpebral crease was significantly larger than that in subjects with visible superior palpebral crease. The supraorbital margin of subjects without visible superior palpebral crease who persistently lifted the eyebrows in primary gaze was higher (rounder) and more obtuse than that of Japanese subjects with visible superior palpebral crease who did not. Conclusions: The mechanical pressure applied to the supraorbital margin by persistently lifting the eyebrows appears to functionally, rather than genetically, create the high (round) and obtuse supraorbital margin.

Introduction: We have reported that a developed lower-positioned transverse ligament between the superior-medial orbital rim and the lateral orbital rim on the lateral horn in the lower orbital fat space antagonizes eyelid opening and folding in certain Japanese to produce narrow eye, no visible superior palpebral crease, and full eyelid. In this study, we confirmed relationship between development of the lower-positioned transverse ligament and presence of the superior palpebral crease. Methods: We evaluated whether (1) digital immobilization of eyebrow movement during eyelid opening and (2) a developed lower-positioned transverse ligament could classify Japanese subjects as being with or without visible superior palpebral crease. Results: Digital immobilization of eyebrow movement restricted eyelid opening in all subjects without visible superior palpebral crease but did not restrict in any subject with visible superior palpebral crease. Macroscopic and microscopic evidence revealed that the lower-positioned transverse ligament behind the lower orbital septum in subjects without visible superior palpebral crease was significantly more developed than that in subjects with visible superior palpebral crease. Conclusions: Since a developed lower-positioned transverse ligament antagonizes opening and folding of the anterior lamella of the upper eyelid in subjects without visible superior palpebral crease, these individuals open their eyelids by lifting the eyebrow with the anterior lamella and the lower-positioned transverse ligament owing to increased tonic contraction of the frontalis muscle, in addition to the retractile force of the levator aponeurotic expansions. In subjects with visible superior palpebral crease, the undeveloped lower-positioned transverse ligament does not antagonize opening and folding of the anterior lamella, and so they open their eyelids by folding the anterior lamella on the superior palpebral crease via the retractile force of the levator aponeurotic expansions.

Objective: The mixed levator and frontalis muscles lack the interior muscle spindles normally required to induce involuntary contraction of their slow-twitch fibers. To involuntarily move the eyelid and eyebrow, voluntary contraction of the levator nonskeletal fast-twitch muscle fibers stretches the mechanoreceptors in Müller's muscle to evoke trigeminal proprioception, which then induces reflex contraction of the levator and frontalis skeletal slow-twitch muscle fibers. The trigeminal proprioceptive nerve has a long intraorbital course from the mechanoreceptors in Müller's muscle to the superior orbital fissure. Since external force to the globe may cause impairment of trigeminal proprioceptive evocation, we confirmed how unilateral blowout fracture due to a hydraulic mechanism affects ipsilateral eyebrow movement as compared with unilateral zygomatic fracture. Methods: In 16 unilateral blowout fracture patients, eyebrow heights were measured on noninjured and injured sides in primary and 60° upward gaze and statistically compared. Eyebrow heights were also measured in primary gaze in 24 unilateral zygomatic fracture patients and statistically compared. Results: In the blowout fracture patients, eyebrow heights on the injured side were significantly smaller than on the noninjured side in both gaze. In the zygomatic fracture patients, eyebrow heights on the injured side were significantly larger than on the noninjured side in primary gaze. Conclusion: Since 60° upward gaze did not recover the eyebrow ptosis observed in primary gaze in blowout fracture patients, such ptosis indicated impairment of trigeminal proprioceptive evocation and the presence of a hydraulic mechanism that may require ophthalmic examination.

Background: Moderate sunburn after prolonged sun exposure is thought to cause long-lasting inflammatory vasodilation due to thermal and ultraviolet radiation from the sun. We previously reported that near-infrared irradiation that simulates solar near-infrared can penetrate the skin and nonthermally affect the dermis, superficial muscles, and other tissues. To clarify the possible effect of near-infrared on long-lasting vasodilation, we evaluated how near-infrared affects subcutaneous vascular smooth muscle cells in rats. Methods: The central back tissues of rats were irradiated with a near-infrared device that simulates solar radiation, which has specialized contact cooling to avoid thermal effects. The total energy emitted was equivalent to approximately 8.75 hours of sunbathing in North America. Histological evaluation was performed on the subdermal plexus over the panniculus carnosus muscle of the near-infrared–irradiated rats at postirradiation days 7, 30, 60, and 90, and compared with nonirradiated controls. The vascular smooth muscle cells were evaluated by the transferase-mediated dUTP nick-end labeling assay and staining with an anti-smooth muscle actin antibody. Results: There was no evidence of inflammation by the increased movement of leucocytes around the dilated vessels in irradiated samples. Near-infrared irradiation induced apoptosis of the vascular smooth muscle cells and significantly induced intense, long-lasting vasodilation of the subdermal plexus at postirradiation day 7. Conclusions: Near-infrared irradiation nonthermally induces long-lasting vasodilation by causing apoptosis of vascular smooth muscle cells. Since solar near-infrared radiation nonthermally induces damage of the subcutaneous tissues, exposed skin should be protected with sunscreens that block not only ultraviolet but also near-infrared radiation.

Objective: We previously reported that near-infrared irradiation simulating solar near-infrared with pre- and parallel-irradiational cooling can penetrate the skin and non-thermally affects dermis, superficial muscles, and so forth. To clarify the possible effect of NIR irradiation on other subcutaneous tissues, we evaluated how near-infrared non-thermally affects subcutaneous adipocytes and bones in rats. Methods: The central back tissues of rats were irradiated with a specialized near-infrared device that simulates solar radiation. The total energy emitted was equivalent to approximately 8.75 hours of sunbathing in North America. Histological evaluation was performed on subcutaneous adipocytes and the spinous process of the near-infrared-irradiated rat and compared with non-irradiated controls. Results: Subcutaneous and bone marrow adipocytes, CD34-positive hematopoietic stem cells in bone marrow, and the cortical bone mass were all significantly increased, whereas the bone marrow cell number was significantly decreased following near-infrared irradiation. Apoptotic cells were detected in the bone marrow at postirradiation days 7 and 30 but were not detected at day 60 or in the controls. Bone marrow cell numbers recovered gradually, whereas the increase in subcutaneous and bone marrow adipocytes, CD34-positive hematopoietic stem cells in bone marrow, and cortical bone mass remained elevated even at day 180. Conclusions: Near-infrared irradiation that simulated solar radiation non-thermally affected subcutaneous adipocytes and bones in rats. It induced putative, non-thermal damage of bone marrow, which was mediated by apoptosis. However, it increased subcutaneous and bone marrow adipocytes, CD34-positive hematopoietic stem cells in bone marrow, and cortical bone mass.

Objective: We previously reported that near infrared (NIR) irradiation weakens frontalis muscle contraction resulting in brow ptosis. In addition, NIR irradiation non-thermally long-lasting thinning of the panniculus carnosus muscle in rats. We sought to determine whether NIR irradiation affects contraction of the corrugator supercilii muscle (CSM). Methods: Three to 5 rounds of NIR irradiation were performed weekly to relax the CSM in 40 patients who had sustained myalgia of the CSM. Each round of irradiation consisted of 10 to 40 doses of NIR irradiation at 28 to 40 J/cm2. We measured changes in the location of the most medial point of the eyebrow rather than evaluation of the glabellar frown line, especially in the 10 unilaterally irradiated patients. We confirmed relief of the CSM myalgia, using a visual analog scale (10 cm in length) in 40 patients. Results: The location of the most medial point of the eyebrow was significantly and durably displaced in the lateral direction when compared with that of the non-irradiated eyebrow, especially in the unilaterally irradiated patients. The visual analog scale score improved from 10 cm to approximately 3 cm in the 40 patients treated. Conclusions: NIR irradiation appeared to induce long-lasting relaxation of the CSM, resulting in the lateral displacement of the most medial point of the eyebrow and relief of its myalgia. Although NIR irradiation flattens skin wrinkles by dermal thickening, it may also non-thermally relax the underlying superficial muscles to reduce wrinkles and myalgia.