Stretching of the Mueller muscle results in involuntary contraction of the levator muscle

Stretching of Putative Mechanoreceptors in the Inferior Tarsal Muscle Regulates Tonic and Clonic Reflex Contractions of Slow-Twitch Fibers in the Palpebral Orbicularis Oculi Muscle Causing Apraxia of Eyelid Opening: A Case Series

The levator palpebrae superioris muscle (LPSM) and facial muscles comprise both fast-twitch fibers (FTFs) and slow-twitch fibers (STFs). Still, they lack the muscle spindles to induce reflex contractions of STFs. Because reflex contractions of STFs in the LPSM and frontalis muscle, which are the major eyelid opening muscles, are induced by stretching of mechanoreceptors in the superior tarsal muscle, those in the palpebral orbicularis oculi muscle (POOM), which is the major eyelid closing muscle, should not be induced by stretching of the same proprioceptors but instead induced by the proprioceptors in the vicinity of the POOM. Apraxia of eyelid opening (AEO) after eyelid closure might be caused by prolonged POOM contraction. Most patients with AEO tend to stretch the upper and lower eyelids by applying contact lenses and eyedrops to disinsert the aponeurosis and retractor from the tarsi. They taught us that pulling down or raising the lower eyelid decreased or increased involuntary contraction of the POOM, which relieved or worsened AEO, respectively. Then, they asked us to have the lower eyelid lowered and the upper eyelid raised surgically. Whenever the upper eyelid is opened by contractions of the LPSM with the global layer of superior rectus muscle (GLSRM), the lower eyelid is concomitantly opened by contractions of the global layer of inferior rectus muscle (GLIRM), which counteracts the contraction of the GLSRM to maintain the visual axis. We hypothesized that patients with retractor disinsertion raise the lower eyelid by eyelid closure to stretch putative mechanoreceptors in the inferior tarsal muscle (ITM), which induces prolonged tonic and clonic reflex contractions of STFs in the POOM, resulting in AEO. To retrospectively verify the hypothesis, we report five cases with AEO. In the first case, AEO was induced by tight eyelid closure but was prevented by pulling down the lower eyelid during eyelid closure. Surgery to reinsert retractors into the tarsi cured AEO. In the second case, the patient sustained both severe aponeurosis-disinserted blepharoptosis and AEO. In this patient, the first surgery to reinsert aponeuroses to the the tarsi cured AEO, but a tight eyelid closure induced prolonged POOM contraction. The second surgery conducted to reinsert the retractors to the tarsi cured AEO. In the third case, with the entire eyelid AEO, surgery done to reinsert the retractors to the tarsi almost cured the entire eyelid AEO. In the fourth case, an increased clonic contraction of the POOM on the right eyelid after a tight eyelid closure was relieved by 4% lidocaine instillation to anesthetize the ITM. In the fifth case, downgaze induced clonic reflex contraction of the right POOM because of the right retractor disinsertion. Thus, prolonged tonic and clonic reflex contractions of STFs in the POOM appeared to be regulated by enhanced stretching of putative mechanoreceptors in the ITM in patients with retractor disinsertion due to increased contractions and microsaccades of FTFs in the GLIRM. Because reflex contractions of STFs in the POOM by stretching of putative mechanoreceptors in the ITM might essentially attach the upper and lower eyelids to the globe, AEO might simply be the increased reflex contraction of the POOM.

Measurements of oculo-palpebral landmarks and evaluation of patient's head position

PURPOSE

Keeping the head in a neutral position is requisite for glasses/lenses/head-up designs, the suitability of oculo-plastic surgery and for the grading the eye shift. Anatomically incompatible glasses are one of the common problems affecting accommodation, reducing comfort and disturbing by causing symptoms such as dizziness and nausea. The oculo-palpebral measurements act as a key determinant in symmetrical facial attractiveness. This study aims to investigate the most effective oculo-palpebral landmarks, head-neutral as the ideal position, taking into account of individual anatomical differences of these patients.

METHODS

100 females and 100 males aged between 18 and 20 years were photographed. Digital photogrammetric measurements were made with the ImageJ program. Interpupillary and interhelical distances, besides bilateral palpebral fissure length and height, and iris diameter were calculated on front-facing photographs.

RESULTS

Mean interpupillary distance was measured wider in males than in females. The mean length of palpebral fissure was 31 mm; palpebral fissure height was 10 mm. These figures were valid in both eyes and gender. The interhelical distance was calculated as the mean and was measured longer in men. Since the measurement values were the same in both sexes and on both sides, they were determined as important landmarks for controlling the head-neutral position, evaluating whether there was a deviation in the eye, and measuring the numerical value when detected.

CONCLUSION

It is essential to check the side-symmetry of the patient's palpebral fissure height, palpebral fissure length, diameter of iris and corneal depth during oculo-plastic invention and artificial design.

Amyotrophic lateral sclerosis and delayed onset muscle soreness in light of the impaired blink and stretch reflexes – watch out for Piezo2

Amyotrophic lateral sclerosis (ALS) is a fatal, multisystem neurodegenerative disease that causes the death of motoneurons (MNs) progressively and eventually leads to paralysis. In contrast, delayed onset muscle soreness (DOMS) is defined as delayed onset soreness, muscle stiffness, loss of force-generating capacity, reduced joint range of motion, and decreased proprioceptive function. Sensory deficits and impaired proprioception are common symptoms of both ALS and DOMS, as impairment at the proprioceptive sensory terminals in the muscle spindle is theorized to occur in both. The important clinical distinction is that extraocular muscles (EOM) are relatively spared in ALS, in contrast to limb skeletal muscles; however, the blink reflex goes through a gradual impairment in a later stage of disease progression. Noteworthy is, that, the stretch of EOM induces the blink reflex. The current authors suggest that the impairment of proprioceptive sensory nerve terminals in the EOM muscle spindles are partially responsible for lower blink reflex, beyond central origin, and implies the critical role of Piezo2 ion channels and Wnt-PIP2 signaling in this pathomechanism. The proposed microinjury of Piezo2 on muscle spindle proprioceptive terminals could provide an explanation for the painless dying-back noncontact injury mechanism theory of ALS.

OUP accepted manuscript

Complications of percutaneous ethanol injection (PEI) for thyroid cyst are rare. Almost all complications reported have been transient, including Horner’s syndrome. We provide herein the first description of persistent blepharoptosis subsequent to PEI, necessitating surgical correction. A 54-year-old woman presented to our hospital with left blepharoptosis that had occurred the day after PEI for a thyroid cyst. She showed 2 mm of blepharoptosis and 1 mm of miosis in the left eye compared to the right eye. Magnetic resonance imaging of the brain demonstrated no abnormalities, and computed tomography detected no lesions in the neck or chest other than the already known cyst. Instillation of phenylephrine eye drops allowed elevation of the left upper eyelid. Considering these findings, we diagnosed the blepharoptosis as part of Horner’s syndrome. The ptosis was corrected by levator aponeurosis advancement. No recurrence has been observed as of 9 months postoperatively.

Muscle Spindles in the Levator Palpebrae Superioris Muscle of Human Adults

ABSTRACT

In this experimental anatomic study, the authors examined the number and distribution of muscle spindles in the levator palpebrae superioris (LPS) muscle of human adults. This study included 11 orbits from 11 cadavers (mean age at death, 81.9 years). The LPS muscles were harvested and equally divided into 5 sections using transverse incisions. Muscle spindles were counted in each section. Consequently, muscle spindles were identified in 4 (36.4%) of the 11 orbits studied. One to 4 muscle spindles were identified in each of these 4 orbits. All muscle spindles were found in the most proximal section (the muscle origin), and no muscle spindles were identified in the other sections. The results indicate that the LPS muscle is associated with a smaller number of muscle spindles as compared with the rest of the extraocular muscles. Since higher muscle spindle numbers are associated with finer motor movements, eyelid opening does not seem to require much precision, compared to ocular movement.

Contralateral eyelid elevation following unilateral upper eyelid retraction repair

Purpose: To report the influence of unilateral upper eyelid retraction repair on the upper eyelid position of the contralateral, non-operative side.Methods: An IRB-approved retrospective chart review was performed to identify patients who underwent unilateral upper eyelid retraction repair. Patient demographics, etiology of upper eyelid retraction, previous surgeries, and periocular measurements from pre-operative and follow-up visits were reviewed.Results: Thirteen patients who underwent unilateral upper eyelid retraction repair due to thyroid eye disease or iatrogenic retraction secondary to ptosis repair demonstrated an elevation in contralateral eyelid height post-operatively. The mean pre-operative MRD-1 was 6.6 mm in the operative eye and 2.6 mm in the contralateral eye. All patients demonstrated a decreased MRD-1 in the operative eye (mean change: -2.6 mm [-38.4%]; standard deviation [SD]: 1.2 mm) and an increased MRD-1 in the contralateral eye (mean change: +1.3 mm [+62.4%]; SD: 0.6 mm) following unilateral upper eyelid retraction repair. The mean post-operative MRD-1 measurements were 4.0 mm ± 0.5 mm and 3.9 mm ± 0.6 mm in the operative and contralateral eyes, respectively.Conclusions: Unilateral upper eyelid retraction repair may induce an elevation of the contralateral upper eyelid position in some patients. The findings in this report may support unilateral intervention in patients with upper lid retraction, especially in the setting of contralateral blepharoptosis.

Histologic Evaluation of Nonvisual Afferent Sensory Upper Eyelid Proprioception

PURPOSE

Recent research has suggested a possible role for proprioception in ipsilateral frontalis activation in the setting of ptosis; however, there has not been any robust histologic or anatomic evidence to support this theory. To further elucidate proprioceptive structures in the eyelid, this investigation uses validated histologic techniques to explore the presence of proprioceptive structures or afferent neural networks in the Levator Palpebrae Superioris (LPS) and Müller muscle.

METHODS

Müller muscle and LPS samples were evaluated by a laboratory with extensive experience with the histology of extraocular muscle proprioception. Immunofluorescence and confocal laser scanning microscopy were used to analyze the tissue samples.

RESULTS

Thirty-four Müller muscle samples and 10 LPS samples were analyzed. Golgi tendon bodies and muscle spindles were not identified in the Müller muscle and LPS samples. This result is expected in the Müller muscle given that these structures are not typically present in smooth muscle, but noteworthy in the skeletal muscle of the LPS. Previously undescribed synaptophysin-positive free nerve terminals within the intermuscular connective tissue of the Müller muscle were identified.

CONCLUSIONS

The nerve terminals identified are anatomically consistent with free nerve endings present in the extraocular muscles that have been implicated in proprioception. These findings advance our current knowledge of the ultrastructure of Müller muscle and the LPS and suggest a possible mechanism for proprioception in the upper eyelid that may have a role in ipsilateral brow elevation in the setting of ptosis.The authors describe proprioception in the upper eyelid: A histologic analysis.

Blepharoptosis Repair: External Versus Posterior Approach Surgery: Why I Select One over the Other

Ptosis surgery is performed via an anterior/external or posterior/internal approach, primarily defined by the eyelid elevator muscle surgically addressed: the levator complex anteriorly or Muller muscle posteriorly. Posterior ptosis surgery via Muller muscle conjunctival resection is an excellent first choice for cases of mild to moderate ptosis with good levator function, as it is predictable, provides a reliable cosmetic outcome, requires no patient cooperation during surgery, portends a lower rate of reoperation, and rarely leads to lagophthalmos and/or eyelid retraction postoperatively. External levator resection is preferred in patients with severe ocular surface/cicatricial conjunctival disease, shortened fornices, and lesser levator function.

Effect of topical Phenylephrine on the upper eyelid crease position

PURPOSE

To investigate the effect of Phenylephrine test on the upper eyelid crease position.

MATERIAL AND METHODS

This study follows a prospective and analytical design and included patients with unilateral acquired involutional ptosis recruited between January 2015 and January 2018. In the Phenylephrine test, 1 drop of Phenylephrine 10% was instilled on the inferior fornix of the ptotic eye and the eyelid crease position was evaluated 10 min after.

RESULTS

A total of 60 patients were included in the final sample. The mean Margin-to-reflex distance 1 (MRD1) of the ptotic eye was 2.1 ± 1.0 and 3.8 ± 0.6 mm before and 10 min after the instillation of Phenylephrine, respectively. The difference between the means was statistically significant (p < 0.001). Ninety-five per cent of the eyes had a positive Phenylephrine test result. Of this, 100% showed a decrease in the height of eyelid crease after the drop. There was a statistically significant decrease in the height of eyelid crease from 10.3 ± 2.5 to 7.8 ± 2.0 mm (p < 0.001).

CONCLUSION

Phenylephrine test not only affects the eyelid position but also the eyelid crease height. We show a significative decrease in eyelid crease height to a symmetrical level with the contralateral lid in all patients that had a positive Phenylephrine test result. This effect is probably due to a posterior lamella shortening secondary to Müller's muscle contraction and suggests that the eyelid crease is not only determined by the projections of levator aponeurosis, but also by the entire force vector of the upper eyelid retractors.

Differences in palpebral fissure height depending on patient's intraoperative head position

Background

Blepharoptosis operations are performed under local anaesthesia, and it is necessary to determine the location where the levator aponeurosis is fixed to the tarsus by checking opening and closing of the eyelids during surgery. Changes in posture during the operation affect the facial condition in various ways. This study was performed to clarify the differences in palpebral fissure height according to intraoperative head position.

Methods

Sixty subjects (48 women and 12 men aged 20-76 years) were enrolled in the study. The palpebral fissure height of the dominant eye was measured in the head-neutral position and 30° head-down position.

Results

The total fissure height in the 30° head-down position was lower than that in the head-neutral position.

Conclusions

The head-down position affects the patient's fissure height and may mislead the operator. Blepharoptosis operation under local anaesthesia should be performed with the patient in the head-neutral position.

Change in Eyelid Position Following Muller's Muscle Conjunctival Resection With a Standard Versus Variable Resection Length

PURPOSE

This study compares the use of a standard 7 mm resection length to a variable 4:1 ratio of resection length to desired elevation nomogram when performing Muller's muscle conjunctival resection surgery.

METHODS

In this cross-sectional case control study, 2 groups were defined. The first underwent Muller's muscle conjunctival resection surgery with a standard 7 mm resection length and the second underwent the same surgery with a variable resection length determined by a 4:1 ratio of resection length to desired elevation nomogram. Groups were matched for age (within 5 years) and sex. Pre- and postoperative photographs were measured digitally. Change in upper marginal reflex distance 1 (MRD1) and final MRD1 were the primary outcome measures. The study was powered to detect a 1 mm difference in MRD1 to a beta error of 0.95.

RESULTS

No significant preoperative differences between the groups were noted. No significant difference in final MRD1 (0.1 mm; p = 0.74) or change in MRD1 (0.2 mm; p = 0.52) was noted. Mean resection length to elevation ratios were 3.9:1 for standard group and 4.3:1 for the variable group (p = 0.54).

CONCLUSION

The authors were not able to detect a significant difference in final MRD1 or change in MRD1 for patients undergoing Muller's muscle conjunctival resection surgery with standard or variable resection lengths. These results tend to argue against a purely mechanical mechanism for Muller's muscle conjunctival resection surgery.

Anterior approach white line advancement: technique and long-term outcomes in the correction of blepharoptosis

PurposeAnterior approach white line advancement presents a novel surgical option for correction of blepharoptosis. The technique draws on several advantages of other approaches. The aim of this study was to present outcomes using this technique at a minimum follow-up of 18 months.Patients and methodsParticipants having undergone anterior approach white line advancement ptosis correction at a single institution were retrospectively recruited at a minimum of 18 months' follow-up. A total of 18 independent eyelid measurements were recorded at final review. Outcomes included long-term rate of surgical success, upper eyelid margin-reflex distance (MRD1) at both early and late post-operative follow-up, inter-eyelid asymmetry, complications, re-operation rate, patient satisfaction, and quality-of-life improvement using the Glasgow Benefit Inventory (GBI). Pre- and post-operative MRD1, as well as inter-eyelid asymmetry, were compared using a two-tailed t-test.ResultsIn total, 82 eyelids of 47 participants were included with a mean follow-up of 2.3 years (range 1.5-3.7). Surgical success was achieved in 91.5%, with a final mean MRD1 of 3.5 mm (95% confidence 3.2-3.7). An increase of 2.4 mm (2.1-2.8) in eyelid height was observed between baseline and long-term follow-up (P<0.0001). No significant change was observed between early and late post-operative follow-up. Pre-operative asymmetry was reduced from 1.0 mm (0.7-1.3) to 0.4 mm (0.3-0.5; P<0.0001). Patient satisfaction was 95.7% with a mean GBI score of +21.8 (13.2-30.3).ConclusionsAnterior approach white line advancement presents an excellent option for patients undergoing ptosis correction with favourable long-term results. Comparisons are made with other techniques with respect to anatomical, functional, and surgical factors.

Proprioceptive Phenomenon With Involutional Ptosis: Evidential Findings in Anophthalmic Ptosis

PURPOSE

To determine the effect of ptosis on compensatory frontalis contraction in patients without visual input and to identify if a sensory stimulus contributes to brow elevation.

METHODS

A prospective study. Clinical photographs were measured by 2 masked oculoplastic surgeons to determine brow height in 8 patients with unilateral ocular prosthesis in 3 conditions: at baseline, after a gold weight was applied to the upper eyelid inducing acute ptosis, and with the gold weight plus topical anesthetic. The measured brow height was then compared between the 3 scenarios.

RESULTS

Mean brow height increased after application of the gold weight when compared with baseline, and this difference reached significance (p = 0.012). After topical anesthetic was applied, the mean brow height decreased but not back to baseline. When mean brow height during the gold weight with topical anesthesia was compared with baseline and with the gold weight only scenarios, the difference was not significant (p > 0.05).

CONCLUSIONS

Frontalis contraction is observed when acute ptosis is simulated in anophthalmic patients, confirming that a contracted visual field cannot be the only stimulus for compensatory brow elevation. A sensory or proprioceptive mechanism is suggested but not confirmed by the trend of reduction in brow elevation with topical anesthesia.

Levator lengthening technique using cartilage or fascia graft for paralytic lagophthalmos in facial paralysis

INTRODUCTION

Lid loading using gold weights has been commonly used to treat paralytic lagophthalmos (PL); however, the procedure has a relatively high complication rate and the availability of these plates varies among social circumstances. We used a levator lengthening (LL) technique, which originally elongated the levator aponeurosis by inserting a fascia graft between the edge of the levator aponeurosis and the tarsal plate. However, because this procedure tends to result in a wide residual lagophthalmos, we changed the graft material from fascia to conchal cartilage. In this study, we describe in detail our experience with LL using the cartilage graft.

METHODS

LL was performed in 18 patients with PL. Fascia grafts were used in seven patients and cartilage grafts in 11. Static reconstructions of the lower eyelid and eyebrow were also performed in most patients. Efficacy was evaluated from patient reports of ocular symptoms and by measuring the palpebral fissure width at opening and closing for both eyes.

RESULTS

All patients experienced improved ophthalmological symptoms, which were more apparent in cartilage cases. The average palpebral fissure at eyelid closure was 1.8 mm in cartilage cases and 4.0 mm in fascia cases. In cases where an eyebrow lift was concurrently performed, the residual lagophthalmos became wider in fascia grafting but remained acceptable in cartilage grafting.

DISCUSSION

LL is a simple and useful procedure for treating PL with higher efficacy when a cartilage graft is used. However, the level of the upper eyelid can be easily adjusted by changing the fixation position of the cartilage. Additional experience is required to obtain more consistent outcomes.

Eyelid Opening with Trigeminal Proprioceptive Activation Regulates a Brainstem Arousal Mechanism

Eyelid opening stretches mechanoreceptors in the supratarsal Müller muscle to activate the proprioceptive fiber supplied by the trigeminal mesencephalic nucleus. This proprioception induces reflex contractions of the slow-twitch fibers in the levator palpebrae superioris and frontalis muscles to sustain eyelid and eyebrow positions against gravity. The cell bodies of the trigeminal proprioceptive neurons in the mesencephalon potentially make gap-junctional connections with the locus coeruleus neurons. The locus coeruleus is implicated in arousal and autonomic function. Due to the relationship between arousal, ventromedial prefrontal cortex, and skin conductance, we assessed whether upgaze with trigeminal proprioceptive evocation activates sympathetically innervated sweat glands and the ventromedial prefrontal cortex. Specifically, we examined whether 60° upgaze induces palmar sweating and hemodynamic changes in the prefrontal cortex in 16 subjects. Sweating was monitored using a thumb-mounted perspiration meter, and prefrontal cortex activity was measured with 45-channel, functional near-infrared spectroscopy (fNIRS) and 2-channel NIRS at Fp1 and Fp2. In 16 subjects, palmar sweating was induced by upgaze and decreased in response to downgaze. Upgaze activated the ventromedial prefrontal cortex with an accumulation of integrated concentration changes in deoxyhemoglobin, oxyhemoglobin, and total hemoglobin levels in 12 subjects. Upgaze phasically and degree-dependently increased deoxyhemoglobin level at Fp1 and Fp2, whereas downgaze phasically decreased it in 16 subjects. Unilateral anesthetization of mechanoreceptors in the supratarsal Müller muscle used to significantly reduce trigeminal proprioceptive evocation ipsilaterally impaired the increased deoxyhemoglobin level by 60° upgaze at Fp1 or Fp2 in 6 subjects. We concluded that upgaze with strong trigeminal proprioceptive evocation was sufficient to phasically activate sympathetically innervated sweat glands and appeared to induce rapid oxygen consumption in the ventromedial prefrontal cortex and to rapidly produce deoxyhemoglobin to regulate physiological arousal. Thus, eyelid opening with trigeminal proprioceptive evocation may activate the ventromedial prefrontal cortex via the mesencephalic trigeminal nucleus and locus coeruleus.

Borderline to Moderate Blepharoptosis Correction Using Retrotarsal Tucking of Müller Muscle: Levator Aponeurosis in Asian Eyelids

BACKGROUND

The purpose of this paper is to report the outcome of retrotarsal tucking of Müller muscle-levator aponeurosis for the correction of borderline to moderate ptosis in conjunction with esthetic blepharoplasty in Asian eyelids and to explore the relationship between the extent of advancement and change in the eyelid position (MRD1).

METHODS

The medical records of 290 consecutive patients who underwent retrotarsal tucking of Müller muscle-levator aponeurosis from February 2005 to November 2011 were reviewed. Of those, 26 patients (51 eyelids) were statistically analyzed. The correction was performed through an external upper blepharoplasty approach. Once the orbital septum was opened, the Müller muscle-levator aponeurosis was advanced and tucked under the posterior surface of the tarsus by a single lifting suture. The average follow-up period was 20.6 months, with a range of 3-68 months.

RESULTS

In 26 patients (51 eyelids), satisfactory results were recorded for 49 of 51 eyelids (96.1 %). The margin reflex distance-1 (MRD1) increased from 1.56 ± 0.70 mm preoperatively to 3.86 ± 0.94 mm postoperatively (p < 0.001, Wilcoxon signed rank test). When 6.1 mm of advancement was implemented, an average MRD1 of 1 mm was achieved. For 7.2 and 8.3 mm of advancement, the average MRD1 achieved was 2 and 3 mm each. A noteworthy complication, although not included in statistical analysis, was one patient who had developed corneal irritation caused by the conjunctival exposure to the non-absorbable suture 3 years after the surgery, which led the subject to have the suture removed.

CONCLUSION

The author concludes that this procedure is one of the most effective surgical options in correcting borderline to moderate blepharoptosis in conjunction with esthetic blepharoplasty. The main advantage of such a method is that once the orbital septum is opened, Müller muscle-levator aponeurosis is easily advanced and tucked under the posterior surface of the tarsal plate without extensive dissection or resection, which is less traumatic and gives a more vertical lifting vector, thus producing excellent cosmetic results and quick recovery.

Levator palpebrae superioris: an anatomical update

The levator palpebrae superioris (LPS) muscle is the main retractor of the upper eyelid, responsible for elevating the upper eyelid and maintaining it in an open position. Sound knowledge of its anatomy and adjacent structures is essential for eyelid surgery. Work from researchers and anatomists over the years continue to enrich our understanding in the anatomy of the LPS. In this review, we present an update on the anatomy of the LPS and its surgical implications. Important adnexa such as Whitnall's ligament, intermuscular-transverse ligament and Müller's muscle are also covered.

Surgical desensitisation of the mechanoreceptors in Müller's muscle relieves chronic tension-type headache caused by tonic reflexive contraction of the occipitofrontalis muscle in patients with aponeurotic blepharoptosis

Proprioceptively innervated intramuscular connective tissues in Müller's muscle function as exterior mechanoreceptors to induce reflex contraction of the levator and occipitofrontalis muscles. In aponeurotic blepharoptosis, since the levator aponeurosis is disinserted from the tarsus, stretching of the mechanoreceptors in Müller's muscle is increased even on primary gaze to induce phasic and tonic reflexive contraction of the occipitofrontalis muscle. It was hypothesised that in certain patients with aponeurotic blepharoptosis, the presence of tonic reflexive contraction of the occipitofrontalis muscle due to the sensitised mechanoreceptors in Müller's muscle, can cause chronic tension-type headache (CTTH) associated with occipitofrontalis tenderness. To verify this hypothesis, this study evaluated (1) what differentiates patients with CTTH from patients without CTTH, (2) how pharmacological contraction of Müller's smooth muscle fibres as a method for desensitising the mechanoreceptors in Müller's muscle affects electromyographic activity of the frontalis muscle, and (3) how surgical aponeurotic reinsertion to desensitise the mechanoreceptors in Müller's muscle electromyographically or subjectively affects activities of the occipitofrontalis muscle or CTTH. It was found that patients had sustained CTTH when light eyelid closure did not markedly reduce eyebrow elevation. However, pharmacological contraction of Müller's smooth muscle fibres or surgery to desensitise the mechanoreceptor electromyographically reduced the tonic contraction of the occipitofrontalis muscle on primary gaze and subjectively relieved aponeurotic blepharoptosis-associated CTTH. Over-stretching of the mechanoreceptors in Müller's muscle on primary gaze may induce CTTH due to tonic reflexive contraction of the occipitofrontalis muscle. Therefore, surgical desensitisation of the mechanoreceptors in Müller's muscle appears to relieve CTTH.

Myoelectric signals of levator palpebrae superioris as a trigger for FES to restore the paralyzed eyelid

Some closed loop FES systems have been designed to restore the blinking function of facial paralysis patients. All of them used myoelectric signal of orbicularis oculi at the normal side as the trigger to stimulate the paralyzed side. They were limited to the one side facial paralysis. Here we proposed that the myoelectric signal of levator palpebrae superioris could be used as the trigger to stimulate the paralyzed orbicularis oculi. Because the levator palpebrae superioris and the innervating nerve are intact, the myoelectric signal of the paralyzed side still could be used as the trigger. It will be more acceptable for the patients and have the potential to resolve the bilateral facial paralysis.

On the somatosensation of vision

The interconnection between vision and somatosensation is already well-established and is further supplemented by the evolutionary link between eyes and photoreceptors, and the functional connection between photosensation and thermoreception. However, our analysis shows that the relation between vision and somatosensation is much deeper and suggests that somatosensation may possibly be the basis of vision. Surprisingly, our photoreceptor itself needs somatosensory proteins for its functioning, and our entire visual pathway depends on somatosensory cues for its functioning.

Muller's muscle resection for ptosis and relationship with levator and Muller's muscle function

PURPOSE

Results of Muller's muscle resection in patients with ptosis and its relationship with levator and Muller's muscle function.

METHODS

Prospective review of medical records of all pateints who underwent open sky Mullerectomy for correction of upper eyelid ptosis. The study period was from January 2008 to July 2009. Levator function, MRD1, Phenylepherine test result and extent of ptosis correction were recorded. Excised muscle tissue in few cases were subjected to histopathology.

RESULTS

In 11 patients who underwent 13 mullerectomy procedures for correction of upper eyelid ptosis, MRD1 increased an average by 2.54 mm. The amount of ptosis correction was 4.28 mm in pateints with either good levator function and/or Muller's action and 1mm in patients where both responses to phenylepherine and levator functions were poor. Histopathology revealed both straited and smooth muscle tissue in the excised specimens in all cases.

CONCLUSION

Mullerectomy porbably involves plication of the posterior layer of the levator aponeurosis. Results of Muller's muscle resection is good in patients with good levator function and/or good Mullers action and poor if both Muller and levator function are poor.

Transcutaneous Blepharoptosis Surgery: Simultaneous Advancement of the Levator Aponeurosis and Müller's Muscle (Levator Resection)

Transcutaneous blepharoptosis surgery with simultaneous advancement of the levator aponeurosis and Müller’s muscle (levator resection) is a popular surgery which is considered effective for all types of blepharoptosis except for the myogenic type. Repair of ptosis cases with good levator function yields excellent results. A good outcome can be also obtained in cases with poor levator function, however, in such cases; a large degree of levator advancement may be required, which may result in postoperative dry eyes, unnatural eyelid curvature and astigmatism. These cases are therefore better treated with sling surgery. With the right patient selection, the levator resection technique is an effective method for ptosis repair.

Müller's muscle: a component of the peribulbar smooth muscle network

PURPOSE

To examine Müller's muscle's horizontal extensions in relation to the peribulbar smooth muscle network.

DESIGN

Observational anatomic study.

PARTICIPANTS

Twenty postmortem orbits (10 right, 10 left) of 15 Asians (8 males, 7 females; age range at death, 61-93 years; mean age, 78.4 years) fixed in 10% buffered formalin.

METHODS

After performing a full-thickness 360° incision of the periosteum around the circumference of the orbit, the periosteum was elevated and finally detached near to the orbital apex. Nerves, blood vessels, and the nasolacrimal duct arising from the orbital wall were cut. The lateral orbital wall then was removed at approximately 3 cm posterior to the orbital rim and the retrobulbar content was incised with a sharp scalpel in a coronal plane. The removed orbital content was incised at a plane passing from a point located 15 mm superior to the upper eyelid margin and the globe equator at 3- and 9-o'clock areas. The sliced specimens were dehydrated and embedded in paraffin, cut into 7-μm thickness sections, and then stained with Masson trichrome.

MAIN OUTCOME MEASURES

The medial and lateral extensions of Müller's muscle in relation to the peribulbar smooth muscle network.

RESULTS

In all specimens, Müller's muscle extended medially and laterally. The medial extension reached the medial rectus muscle pulley, which is rich in smooth muscle fibers. The lateral extension reached the lateral rectus muscle pulley by passing through the lacrimal gland fascia of the palpebral lobe, in which 12 specimens also showed a direct extension to the lateral rectus muscle pulley in the posterior part.

CONCLUSIONS

Müller's muscle has a medial and a lateral extension to the peribulbar smooth muscle network. These new findings indicated that Müller's muscle is not an independent structure in the upper eyelid, but rather a component of the peribulbar smooth muscle network.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Peripheral branching of levator superioris muscle and Müller muscle origin

PURPOSE

To examine the structure of the distal levator superioris muscle and the origin of the Müller muscle.

DESIGN

Experimental dissectional study.

METHODS

Specimens from 10 postmortem upper eyelids and orbits of 7 white cadavers (6 right eyes and 4 left eyes; age range, 78 to 101 years of age at death; age average, 87.7 years) were used for microscopic observations. The upper eyelids and orbits with sagittal full-thickness sections of the central part were examined microscopically using Masson trichrome staining.

RESULTS

Sections from 9 of the specimens were suitable for analysis. The levator superioris muscle divided into a superior and an inferior branch by connective tissue in the peripheral region in all 9 samples. Although the thickness of each branch varied, that of the superior branch tended to be thicker than that of the inferior branch. In 8 specimens of 7 cadavers, the Müller muscle originated from the distal end of the inferior branch of the levator superioris muscle. In one specimen, the Müller muscle originated from the distal end as well as the posterior aspect of the levator superioris muscle. The levator aponeurosis originated from the superior branch.

CONCLUSIONS

The distal levator superioris muscle consisted of a branched structure, and the Müller muscle originated from the inferior branch of the levator superioris muscle.

Feeling darkness: a visually induced somatosensory illusion

Although the five primary senses have traditionally been thought of as separate, examples of their interactions, as well as the neural substrate possibly underlying them, have been identified. Arm position sense, for example, depends on touch, proprioception, and spatial vision of the limb. It is, however, unknown whether position sense is also influenced by more fundamental, nonspatial visual information. Here, we report an illusion that demonstrates that the position sense of the eyelid partly depends on information regarding the relative illumination reported by the two eyes. When only one eye is dark-adapted and both eyes are exposed to a dim environment, the lid of the light-adapted eye feels closed or "droopy." The effect decreases when covering the eye by hand or a patch, thus introducing tactile information congruent with the interocular difference in vision. This reveals that the integration of vision with touch and proprioception is not restricted to higher-level spatial vision, but is instead a more fundamental aspect of sensory processing than has been previously shown.

Predictability of conjunctival-Müellerectomy for blepharoptosis repair

PURPOSE

To assess the predictability of the algorithm used to determine the amount of tissue resection for conjunctival-Müellerectomy during blepharoptosis repair.

METHODS

A consecutive case series of all patients undergoing conjunctival-Müellerectomy during blepharoptosis repair between July 2001 and February 2005. All of the cases had a positive phenylephrine test, and the mean preoperative upper marginal reflex distance (MRD1) was +1.60 mm (range: -1 +/-3.5 mm). Each patient underwent excision according to the following algorithm: 10 mm of resection for 2 mm of ptosis, 8 mm of resection for 1.5 mm of ptosis, and 6 mm of resection for 1 mm of ptosis.

RESULTS

Fifty-five patients underwent conjunctival-Müellerectomy during blepharoptosis repair on 73 eyelids, using the above algorithm. Thirty-seven cases were unilateral and 18 were bilateral. The mean postoperative MRD1 was +3.42 mm (range 0-+4.5 mm). Postoperative symmetry was found in 42 of 55 patients (76.4%) after one surgical procedure. Patient satisfaction based on contour, symmetry and height after one repair was achieved in 52 of 55 patients (94.55%). There were three reoperations for previous undercorrection.

CONCLUSION

This algorithm quantifies conjunctival-Müellerectomy during blepharoptosis repair. Excellent and very predictable results are obtained by a technique that is both simple and achievable in a short operating time.

Alternative etiology and surgical correction of acquired lower-eyelid entropion

When increased contraction of the levator muscle accompanied by the superior rectus muscle compensates for aponeurotic blepharoptosis, increased contraction of the inferior rectus muscle for foveation retracts the lower eyelid through the capsulopalpebral fascia, showing the lower sclera. We hypothesized that in patients with aponeurotic blepharoptosis, the capsulopalpebral fascia excessively retracts the posterior lamella of the lower eyelid alone while keeping the anterior lamella unretracted, especially in patients with both weak extension of the capsulopalpebral fascia to the pretarsal anterior lamella and increased contraction of the orbicularis oculi muscle, resulting in entropion. Aponeurotic reinsertion to the tarsus for the upper eyelid improved entropion in 15 younger patients. Surgical disinsertion of the capsulopalpebral fascia from the tarsus and creation of a cicatricial connection between the pretarsal skin and the tarsus for the lower eyelid corrected entropion in 15 elderly patients. Both procedures also corrected the lower scleral show.

Pathogenesis and surgical correction of involuntary contraction of the occipitofrontalis muscle that causes forehead wrinkles

Assuming that an agonistic function is present to maintain an adequate visual field, we hypothesized that stretching of the mechanoreceptor of Mueller muscle induces involuntary contraction of the occipitofrontalis muscle, as well as the levator muscles. In patients with aponeurotic blepharoptosis, both unilateral instillation of phenylephrine to contact Mueller smooth muscle fibers and unilateral aponeurotic fixation ipsilaterally reduced the eyebrow height during primary and upward gazing. Bilateral aponeurotic fixation bilaterally reduced the eyebrow height, with fewer forehead wrinkles. Stretching of the mechanoreceptor of Mueller muscle induces involuntary contraction of the bilateral levator muscles. Its increased stretching may induce involuntary contraction of the ipsilateral occipitofrontalis muscle via the mesencephalic trigeminal nucleus and the facial subnucleus as another stretch reflex. The involuntary contraction of the occipitofrontalis muscle that causes forehead wrinkles during primary gazing can be corrected by the aponeurotic fixation to reduce the stretching of Mueller muscle.

Upgaze eyelid position allows differentiation between congenital and aponeurotic blepharoptosis according to the neurophysiology of eyelid retraction

To differentiate between congenital and aponeurotic blepharoptosis, we investigated whether upgaze with stretching of the mechanoreceptor of Mueller muscle increases involuntary reflex contraction of the levator slow-twitch muscle fibers. In 50 cases each of unilateral congenital blepharoptosis and of asymmetric aponeurotic blepharoptosis, the mean increases by upgaze in the upper eyelid margin to the line between the medial and lateral canthi as upper eyelid retraction distance (UERD) of the ptotic eyelid 0.4 mm and 2.9 mm, respectively. These were significantly smaller and significantly larger than those of the corresponding nonptotic eyelid, 2.0 mm and 2.3 mm, respectively.Worsening of ptosis on upgaze is common in congenital ptosis and is an abnormal differentiating sign, lacking the involuntary reflex contraction. Improvement of ptosis on upgaze is common in aponeurotic blepharoptosis and likely represents a normal physiological process, restoring the involuntary reflex contraction.

A stretch reflex in extraocular muscles of species purportedly lacking muscle spindles

It is generally assumed that proprioceptive feedback plays a crucial role in limb posture and movement. However, the role of afferent signals from extraocular muscles (EOM) in the control of eye movement has been a matter of continuous debate. These muscles have atypical sensory receptors in several species and it has been proposed that they are not supported by stretch reflexes. We recorded electromyographic activity of EOM during passive rotations of the eye in sedated rats and squirrel monkeys and observed typical stretch reflexes in these muscles. Results suggest that there is a similarity in the reflexive control of limb and eye movement, despite substantial differences in their biomechanics and sensory receptors. Like in some limb skeletal muscles, the stretch reflex in EOM in the investigated species might be mediated by other length-sensitive receptors, rather than muscle spindles.

Isolated Muller's muscle resection for the correction of blepharoptosis

PURPOSE

To assess the outcome of isolated Muller's muscle resection with preservation of conjunctiva in patients with blepharoptosis and good to moderate levator function.

METHODS

This study was designed as a prospective, nonrandomised case series. Thirty-four eyes of 27 blepharoptosis patients were operated on, who were phenylephrine test-negative as well as positive. Open-sky Muller's muscle resection was performed with preservation of the conjunctiva. Main outcome measures were increase in margin reflex distance (MRD1), eyelid contour, and symptoms and signs of dry eye.

RESULTS

The mean increase in MRD1 was 2.75 mm. All but one patient (96%) had upper lid margins resting at or up to 1 mm below the limbus and obtained symmetry to within 0.5 mm of the fellow eye. No patients had symptoms or signs of dry eye.

CONCLUSION

Isolated Muller's muscle resection is effective for the correction of ptosis in patients with moderate to good levator function. This is irrespective of the lid's response to phenylephrine. Preservation of conjunctival tissue eliminates concerns about dry eye, and also preserves the full height of the fornix.

The occipitofrontalis muscle is composed of two physiologically and anatomically different muscles separately affecting the positions of the eyebrow and hairline

After the surgical correction of aponeurotic blepharoptosis or blepharoplasty, the positions of the eyebrow and hairline change as if the frontal belly is independent from the occipital belly of the occipitofrontalis muscle. Therefore, the occipitofrontalis muscle was studied physiologically with electromyographic evaluation in healthy subjects and anatomically with cadaver dissections. Along with contraction of the levator muscle to maintain an adequate visual field, at a less upward gaze position, contraction of only the frontal belly was induced, and at a more upward gaze position, contraction of both the frontal and the occipital bellies was always induced to lift the eyebrow with the upper eyelid skin. The superficial fascia overlying the occipital belly becomes the temporoparietal fascia and ends at the superior end of the frontal belly, thus creating a superficial musculoaponeurotic system that lifts the eyebrow and pulls the scalp forwards. Beneath the superficial musculoaponeurotic system, the occipital belly of the occipitofrontalis muscle becomes the galea aponeurotica and inserts into the underside of the frontal belly, thus creating a deep musculoaponeurotic system that pulls the superficial musculoaponeurotic system with the scalp backwards. Thus, the occipitofrontalis muscle appears to be composed of two physiologically and anatomically different muscles.

Pathogenesis and surgical correction of dynamic lower scleral show as a sign of disinsertion of the levator aponeurosis from the tarsus

The purpose of this study was to confirm whether lower scleral show is caused by the disinsertion of the levator aponeurosis from the tarsus. Aponeurotic advancement by vascular clips or by surgery involving the orbital septum significantly lowered the global position in the orbit and significantly diminished the degree of retraction of the lower eyelid, resulting in satisfactory improvement of lower scleral show in 100 patients with various aponeurotic blepharoptosis. Therefore, we propose the pathogenesis of lower scleral show as follows: additional contraction of the levator muscle to compensate for the disinsertion of the levator aponeurosis from the tarsus for maintenance of an adequate visual field is accompanied by additional contraction of the superior rectus muscle through the strong intermuscular fascia, resulting in upward rotation of the globe. To maintain the horizontal visual axis and foveation without inclination of the head in the primary gaze position, additional contraction of the inferior rectus muscle is induced, which pulls upon the inferior suspensory ligament of Lockwood and the capsulopalpebral fascia. The former displaces the globe upwards and the latter retracts the lower eyelid, resulting in dynamic lower scleral show as a sign of disinsertion of the levator aponeurosis from the tarsus, which can be surgically corrected.

Open Sky M??ller Muscle-Conjunctival Resection in Phenylephrine Test-Negative Blepharoptosis Patients

PURPOSE

To assess the efficacy of Müller muscle-conjunctival resection in patients in whom the phenylephrine test was negative.

METHODS

A non-randomized, prospective clinical trial was conducted on 20 eyelids of 15 consecutive patients with blepharoptosis who showed no change in the upper eyelid margin-reflex distance (MRD1) following instillation of topical phenylephrine. The technique used was open sky Müller muscle-conjunctival resection.

RESULTS

The mean MRD1 increased by 3.3 mm. No patient required augmentation of the procedure, and all patients had excellent appearance of their skin crease and eyelid contour. No complications arose from the procedure, including no incidence of dry eye symptoms or signs.

CONCLUSIONS

Müller muscle-conjunctival resection may offer a safe and effective means of treating blepharoptosis despite a negative phenylephrine test.