Structure of the muscles of the upper eyelid

Levator palpebralis superioris histopathologic findings in congenital ptosis and surgical outcome after its resection: Is there any association?

PURPOSE

To evaluate the histopathologic findings of Levator palpebralis superioris (LPS) muscle biopsy after LPS resection for treatment of congenital ptosis and its possible relation with surgical outcomes.Please confirm if the author names are presented accurately and in the correct sequence (given name, middle name/initial, family name). Author 4 Given name: [Seyed Mohsen] Last name [Rafizadeh]. Author 6 Given name: [Seyed Ali] Last name [Sonbolestan].Also, kindly confirm the details in the metadata are correct.The author names and the sequence are correct.

METHODS

Congenital ptosis patients were enrolled in this retrospective study. All of them underwent full ophthalmologic examination included of Margin-reflex distance 1 (MRD-1) and LPS function measurement preoperatively. The patients were followed for 3 months for the postoperative period and after that the measurements were repeated. Histologic parameters including percentages of fat, striated and smooth muscle, and fibrous tissue. The histopathologic findings and their possible correlation with the measurements are analyzed.

RESULTS

Sixty-seven patients with unilateral congenital ptosis were enrolled. 45 patients (67.2%) were males. The mean age of patients was 16.10 ± 11.18 years. The patients' MRD-1 was improved significantly from 0.82 ± 1.26 mm to 3.85 ± 1.25 mm after LPS resection (P = 0.000). The success rate was 80.3%. There were no correlations between MRD change and histopathologic tissue percentages but significant correlation was found between success of surgery and fibrous tissue percentage of resected sample (P = 0.033).

CONCLUSIONS

The histopathology of the LPS may be useful in prediction of surgical outcome after LPS resection in congenital ptosis patients. The percentage of fibrous tissue play an important role.

Stretching of Mechanoreceptors in Superior Tarsal Muscle Reflexively Contracts Slow-Twitch Fibers in Facial Expression Muscles: A Case Series

Levator palpebrae superioris muscle (LPSM) and facial muscles comprise fast-twitch fibers (FTFs) and slow-twitch fibers (STFs) but lack muscle spindles required to contract STFs reflexively. Voluntary contractions and microsaccades of FTFs in LPSM stretch mechanoreceptors in superior tarsal muscle (STM) to induce phasic contractions of STFs in LPSM and frontalis muscle via mesencephalic trigeminal nucleus (MTN). They also induce prolonged contractions of STFs in bilateral frontalis and orbital orbicularis oculi muscles and physiological arousal via MTN and rostral locus coeruleus (LC). We hypothesized that stretching of mechanoreceptors in STM also induces prolonged contractions of STFs in other facial expression muscles (FEMs) via rostral LC. To verify this hypothesis, we reported a case series of abnormal contractions of FEMs due to aponeurosis disinsertion and disordered mechanoreceptor stretching. The first and second cases, which showed unilaterally and bilaterally sensitized mechanoreceptors, respectively, recorded increased prolonged contractions of ipsilateral and bilateral grimacing muscles, respectively. The third and fourth cases with asymmetrically and bilaterally desensitized mechanoreceptors experienced asymmetrically and bilaterally decreased prolonged contractions of grimacing and smiling muscles, respectively. Preoperatively and after surgery was performed to adjust mechanoreceptor stretching and reinsert aponeuroses into tarsi, we evaluated prolonged contractions of grimacing and smiling muscles during primary gazing and facial expression movements. Surgery satisfactorily cured abnormal prolonged contractions of grimacing and smiling muscles. Stretching of mechanoreceptors in STM by microsaccades or voluntary contractions of FTFs in LPSM might activate rostral LC via MTN, which tonically or phasically stimulates FEM motor neurons to reflexively contract their STFs, respectively.

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.

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.

[The role of Muller's muscle in the occurrence and surgical treatment of the upper eyelid ptosis]

Muller's muscle of the upper eyelid (MM) remains a poorly understood anatomical structure, so its role in the emergence of upper eyelid ptosis provokes certain interest. This literature review examines the gradual rise of attention devoted to MM and describes existing methods of its surgical treatment. Despite progress in ptosis surgery, much remains unsolved. Taking into account the available literature data, it is necessary to further advance histological studying of MM, which will help develop pathogenetically founded surgical treatment of acquired upper eyelid ptosis.

The Type and Content of Collagen Fibers of the Levator Aponeurosis in Patients With Simple Congenital Blepharoptosis

BACKGROUND

The pathogenesis of congenital blepharoptosis remains controversial and most of the studies focused on the histologic changes of the levator muscle. However, thickening of the aponeurosis was reported in congenital blepharoptosis. And the thickness of the levator aponeurosis was found to be correlated with the levator function in congenital dysmyogenic blepharoptosis.

PURPOSE

The authors conducted this research to investigate the histological changes of the levator aponeurosis of simple congenital blepharoptosis patients.

PATIENTS AND METHODS

The authors analyzed 12 levator aponeurosis from ptosis patients and 21 levator aponeurosis from the cadaver specimens without relative medical history. The specimens were stained with hematoxylin and eosin as well as Sirius red. The sections were examined under light-microscopy. The content and type of collagen fibers were examined with the photos taken of the sections stained with Sirius red under polarized light-microscopy.

RESULTS

The content and proportion of type I collagen increased significantly in the patient group compared with the cadaver group. The proportion of type I collagen was 97.5% in the patient group, while it was 51.5% in the cadaver group. However, no correlation was found either between the levator strength, degree of ptosis and the proportion of type I collagen in the patient group or between age, gender and proportion of type I collagen in the cadaver group.

CONCLUSIONS

To our knowledge, this is the first time this phenomenon was discovered. The increase of type I collagen in the levator aponeurosis of the simple congenital blepharoptosis patients may imply the increased stiffness and undermined ability of transmitting forces, dissipate energy and prevent mechanical failure in the levator aponeurosis.

A Study of Histopathologic Evaluation and Clinical Correlation for Isolated Congenital Myogenic Ptosis and Aponeurotic Ptosis

PURPOSE

To evaluate light microscopy and transmission electron microscopy findings of levator muscle/aponeurosis materials and their correlation with clinical findings in isolated congenital myogenic and aponeurotic blepharoptosis.

METHODS

Demographic and clinical data were obtained from patients. Qualitative and quantitative evaluations for muscle fiber morphology were performed using light microscopy and transmission electron microscopy on tissue samples which were obtained from the most proximal part of the aponeurosis excised during levator muscle/aponeurosis resection surgery.

RESULTS

Seventeen (55%) of the cases were isolated congenital myogenic ptosis, and 14 (45%) were aponeurotic ptosis. Muscle bundle splitting, cytoplasmic loss, and centrally located nuclei were observed in both groups. Muscle tissue covered 25% of the sample in 67% of the cases, 50% in 11%, 75% in 11%, and 100% in 11% in the myogenic group. In the aponeurotic group, muscle tissue covered 25% of the sample in 44.5% of the cases, 50% in 11%, and 100% in 44.5% (χ, p = 0.52). Myofibrillar loss areas accompanied by Z-line disorganization which were occupied by degenerated organelles were present in both groups under transmission electron microscopy, and findings were not significantly different between groups (χ, p > 0.05). Mean mitochondrial diameter was significantly larger in aponeurotic ptosis (Mann-Whitney U, p = 0.047). No correlation was found between functional and microscopic parameters.

CONCLUSION

Decreased amount of striated muscle and the presence of fiber damage indicators were observed in both groups. Muscle fiber loss in myogenic ptosis may be a feature of muscle dysgenesis. Ultrastructural damage in aponeurotic ptosis may be explained with increased oxidative stress or long-term contractile stress. Further genetic and immunohistochemical studies will be helpful to further understand the pathogenesis of diseases.

[Fatty degeneration of upper tarsal muscle as etiological factor of acquired upper eyelid ptosis]

PURPOSE

To study the histological structure of the upper tarsal muscle (Müller's muscle of the upper eyelid) in patients with acquired ptosis and to confirm the presence of its fatty degeneration as an understudied etiological factor of upper eyelid ptosis.

MATERIAL AND METHODS

A retrospective analysis was performed covering 79 biopsy samples of Müller's muscle of the upper eyelid obtained intraoperatively. Histological examination was performed with samples prepared by waxing. Planning the surgery included determination of basic parameters and the 'transparency' symptom; the Müller's muscle projection area was examined in the inverted upper eyelid, and ultrasound biomicroscopy (UBM) of the upper eyelid structures was performed.

RESULTS

Among the study subjects, a group of 11 patients with isolated fatty infiltration of the upper tarsal muscle was identified. At the preoperative stage, in the group of patients with upper eyelid eversion, visibly thickened Müller's muscle advancing on the tarsus could be observed, as well as negative 'transparency' symptom; UBM showed thickened 'conjunctiva - Müller's muscle' complex, and a large number of hypoechogenic inclusions in the muscle in comparison with the intact eye. The removed muscle was thickened, yellow, with increased density and rigidity. Microsection of the histological preparations revealed fat cells located among bundles of smooth muscle fibers of the upper tarsal muscle and dispersion of smooth myocytes on the background of fat infiltration.

CONCLUSION

The presence of dystrophic changes in the upper tarsal muscle is proved with clinical, macromorphological and pathohistological methods; they can be one of the independent causes of acquired upper eyelid ptosis.

Influence of fatty deposits in the levator aponeurosis/levator palpebrae superioris muscle on outcomes of aponeurotic repair in a Japanese population

PURPOSE

To examine a part of the levator aponeurosis/levator palpebrae superioris (LPS) muscle that did not have fatty deposits in patients with aponeurotic blepharoptosis. We also analysed the relation between this length and surgical outcome after transcutaneous aponeurotic repair.

METHODS

We measured the vertical length from the distal end of the anterior layer of the levator aponeurosis to the most distal point of fatty deposits in the levator aponeurosis/LPS muscle (non-fatty-deposit length) in 94 eyelids. Surgical success was defined as a postoperative margin reflex distance-1 (MRD-1) of 2.0-5.0 mm at 3 months postoperatively. The eyelids were classified into two groups: a surgical success group (group A, 76 eyelids) and an undercorrected group (group B, 18 eyelids). Group A was subdivided according to the evidence of a fatty deposit (group A1, fat present, 70 eyelids; group A2, fat absent, 6 eyelids).

RESULTS

The non-fatty-deposit measurement was significantly longer in group A1 than in group B (p = 0.035). The levator aponeurosis was less advanced in groups A1 and A2 than in group B (both, p < 0.001), and the eyelids in groups A1 and A2 obtained a higher MRD-1 than those in group B (both, p < 0.001).

CONCLUSIONS

Eyelids with less fat deposit required less advancement of the levator aponeurosis and obtained more favourable surgical results. Intraoperative findings of eyelids with and without fatty deposits and measuring the non-fatty-deposit length may be useful predictive parameters for outcomes of transcutaneous aponeurotic repair.

Gross and microscopic study of insertion of levator palpebrae superioris and its anatomical correlation in superior palpebral crease formation and its clinical relevance

BACKGROUND

To study insertion of LPS and correlate anatomically the formation of superior palpebral crease and its clinical relevance in section of Indian population.

METHODS

Twenty-five human eyelids from cadavers ranging from 15-80 years were studied by dissection and histology.

RESULTS

The levator aponeurosis traverses through interfascicular space of orbicularis oculi with twenty four inserting into subcutaneous tissue. Low septo aponeurotic sling or preaponeurotic fat was not observed. Lower one third tarsal insertion seen in twenty four specimens. Fibres become denser as it reaches the connective tissue anterior to tarsal plate. The crease was at different levels in relation to the tarsal insertion.

CONCLUSION

The aponeurosis insertion is either to the skin, the subcutaneous tissue or into the interfascicular space of the orbicularis. The present study reaffirms the insertion of LPS to the subcutaneous tissue of the eyelid with an extension reaching lower one third of the tarsal plate. The tissues in the anterior tarsal plate are closely packed but to act as a single complex to form a dynamic crease has not been confirmed in the study. No gross or histological difference was observed in the skin of the eyelid in the vicinity of the crease. The pattern of insertion of LPS aponeurosis plays a direct role in the formation of superior palpebral crease an important role in surgeries for Ptosis. The eyelids studied were of Indian origin with crease, and further comparative studies needs to be done for the precise anatomical explanation of single fold eyelids.

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.

The Post-Levator Aponeurosis Fat Pad

PURPOSE

To examine the post-aponeurotic space and to confirm and define the presence of a post-aponeurosis fat-pad.

METHODS

Experimental anatomic study. Nineteen-orbits from 10 freeze-preserved, unembalmed cadavers of caucasian subjects. In 12 orbits of 7 cadavers, a transconjunctival dissection of the everted upper eyelid was undertaken. Müller's muscle (MM) and conjunctiva were dissected as a composite flap exposing the posterior surface of the aponeurosis (LA) and the commencement of the levator palpebrae superioris (LPS) muscle. Anatomical localisation was agreed by 2 senior surgeons and an anatomist (VM). In the remaining 7 orbits a 1cm central upper eyelid wedge-excision was paraffin-embedded and studied histologically.

RESULTS

Nineteen upper-eyelids from 10 freeze-preserved, unembalmed caucasian cadavers (5-male, 5-female, mean age 80.9; range 67-91 years) were studied. Of 12 eyelids of 7 cadavers, dissected and macroscopically evaluated, a fat-pad was identified in the post-aponeurotic space of all eyelids. Of these, 8 (66%) were predominantly diffuse. The remainder, mixed diffuse-discrete. All 4 of the latter category appeared multi-lobular. The fat-pad was seen to lie predominantly centro-medially, overlying MM, extending superiorly beyond the LA to lie posterior to LPS. Of the 7 upper eyelid wedge-excisions examined microscopically, a fat-pad was identified in all post-aponeurotic spaces, lying between 2 distinct tracts of smooth muscle. The anterior smooth muscle tract was intimately related to the posterior aspect of the LA, in keeping with the posterior smooth muscle layer of the aponeurosis. The posterior smooth muscle tract was in keeping with MM, thicker than the anterior layer, multi-layered and in 6 of 7 eyelids, interspersed with fat.

CONCLUSIONS

We confirm and describe a distinct layer of fat in the post-aponeurotic space, consistently found between MM and the posterior smooth muscle layer of the aponeurosis. We refer to this as the post-aponeurosis fat-pad. These findings provide further anatomical detail for the surgeon undertaking blepharoptosis surgery, who may, in some cases, mistake the presence of fat in this space either for the pre-aponeurotic fat-pad, or for degenerative changes within MM that lies deep to it.

Animal models for investigating benign essential blepharospasm

The focal dystonia benign essential blepharospasm (BEB) affects as many as 40,000 individuals in the United States. This dystonia is characterized by trigeminal hyperexcitability, photophobia, and most disabling of the symptoms, involuntary spasms of lid closure that can produce functional blindness. Like many focal dystonias, BEB appears to develop from the interaction between a predisposing condition and an environmental trigger. The primary treatment for blepharospasm is to weaken the eyelid-closing orbicularis oculi muscle to reduce lid spasms. There are several animal models of blepharospasm that recreate the spasms of lid closure in order to investigate pharmacological treatments to prevent spasms of lid closure. One animal model attempts to mimic the predisposing condition and environmental trigger that give rise to BEB. This model indicates that abnormal interactions among trigeminal blink circuits, basal ganglia, and the cerebellum are the neural basis for BEB.

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.

Punctal and canalicular anatomy: implications for canalicular occlusion in severe dry eye

PURPOSE

To characterize the microscopic anatomy of the lacrimal punctum and canaliculi in relation to the tarsal plate, muscle of Riolan, and Horner muscle; and to report a novel technique to excise the horizontal canaliculus in severe dry eye patients.

DESIGN

Observational anatomic study and a retrospective case series.

METHODS

The microscopic anatomy was studied in 86 eyelids of 25 cadavers (age range: 45-96 years, mean: 79.5 years). Surgery was performed on 18 canaliculi of 7 patients with dry eyes (age range: 37-69 years, mean: 59.9 years). In the microscopic study, 32 eyelids were incised sagittally, 38 eyelids were incised horizontally (1 mm from the eyelid margin), and 16 eyelids were incised parallel to the tarsal plate. All specimens were stained with Masson trichrome. In the surgical group, probe-guided horizontal canalicular excision with incision of the Horner muscle to the lateral edge of the lacrimal caruncle was performed. Both canalicular stumps were cauterized.

RESULTS

In the microscopic anatomic study, the punctum and the vertical canaliculus were part of the tarsal plate with the muscle of Riolan, whereas the horizontal canaliculus was surrounded by the Horner muscle. In the surgical group, all the operated canaliculi were completely occluded without recanalization 12 months postoperatively. No complications were recorded.

CONCLUSIONS

Based on microscopic anatomic findings that the lacrimal punctum and the vertical canaliculus are part of the tarsal plate, and that the horizontal canaliculus is surrounded by the Horner muscle, excision of the horizontal canaliculus may be an effective technique to treat patients with severe dry eyes.

Timetable for upper eyelid development in staged human embryos and fetuses

In this study, we examined the development of the upper eyelids to provide a basic understanding of gross anatomical structures and information relative to mechanisms of congenital anomalies in the upper eyelids. We studied the upper eyelids by external and histological observation in 48 human embryos and in fetuses from 5 to 36 weeks postfertilization. The upper eyelid fold began to develop at Stage 18. Upper and lower eyelids fused from the lateral cantus at Stage 22, and fusion was complete by 9 weeks of development. Mesenchymal condensations forming the orbital part of the orbicularis oculi (OO), tarsal plate, and the eyelashes and their appendages, were first seen at Week 9. Definite muscle structures of the upper eyelid, such as the orbital part of the OO and the levator palpebrae superioris and its aponeurosis, and the Müller's muscle were observed at 12 and 14 weeks, respectively. In addition, orbital septum, arterial arcade and orbital fat pad, and tarsal gland (TG) were apparent at 12, 14, and 18 weeks, respectively. Opening of the palpebral fissure was observed at Week 20. In addition, we defined the directional orientation between the levator aponeurosis and orbital septum and the growth pattern of the TG. Our results will be helpful in understanding the normal development of the upper eyelid and the origins of upper eyelid birth defects.

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.

Visible iris sign as a predictor of problems during and following anterior approach ptosis surgery

OBJECTIVE

To describe the pre- and postoperative features of the visible iris sign (VIS), which is the apparent visibility of iris colour through a closed upper eyelid, in patients undergoing anterior approach surgery for severe involutional aponeurotic ptosis, and to assess its effect on postoperative outcome.

DESIGN

Prospective, comparative interventional case series.

METHODS

Prospective series of all patients undergoing surgery for severe involutional aponeurotic ptosis during a 16-month period at a single centre.

INCLUSION CRITERIA

Severe involutional ptosis (upper eyelid margin reflex distance (MRD) ≤1 mm) treated by anterior-approach surgery.

MAIN OUTCOME MEASURES

Presence of VIS, type of ptosis (primary or recurrent), preoperative MRD, levator function and skin crease height, documented unusual intra-operative findings, postoperative complications, and follow-up time.

RESULTS

Of 133 procedures for involutional aponeurotic ptosis, 96 procedures (56 patients) were included in the study. In total, 12 patients (21%, 12/56, 2 males, and 10 females) had been identified as having VIS preoperatively. In order to avoid any selection bias, only patients with severe degree of ptosis were included in the two groups with the two groups being alike in the preoperative lid height, levator function or the skin crease. In the VIS group, 55% (12/22) had a thinned, significantly retracted levator aponeurosis and a thin tarsus prone to full-thickness suture passes (36.3%, 8/22) during aponeurosis reattachment. Immediate persistent overcorrection during surgery was seen in three procedures, with one patient having an under corrected outcome when treated with a hang-back suture. In the non-VIS group, no patients were documented intra-operatively, as having significant retraction of the levator aponeurosis. However, 14% (10/74) of the eyelids were recorded as having a very attenuated levator and one patient (3%, 1/44) was noted to have a floppy tarsus that was difficult to suture. The total incidence of intra-operative difficulties during surgery were 78% in the VIS group and 22% in the non-VIS group. Mean postoperative follow-up was 22 weeks. (median 18, range 12-64). The overall success rates were 63.6% (14/22) in the VIS group, compared with 77.0% (57/74) in the non-VIS group (P = 0.260). After excluding cases undergoing concurrent blepharoplasty and non-Caucasians, success rates were 57.1% (4/7) and 69.2% (9/13) in the VIS and non-VIS groups, respectively (P = 0.598). All failures were because of under-correction.

CONCLUSION

The VIS is a clinical sign of severe involutional ptosis. Patients with VIS have one or more features, including a retracted levator aponeurosis, a thinned tarsus prone to full-thickness suture passes, and a tendency for immediate persistent overcorrection following levator advancement. Preoperative identification of VIS may help in appropriate patient counselling, procedure selection, anticipation of intraoperative difficulties, and possibly further standardisation of future cohorts when evaluating the results of involutional ptosis surgery. PRÉCIS: The authors describe the pre-, intra- and postoperative features of visible iris sign. They discuss the success rates of anterior approach surgery in VIS patients and discuss the contributing factors for a poorer outcome.

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.

Levator superioris muscle function in involutional blepharoptosis

PURPOSE

To assess the role of muscular degeneration, we evaluated the correlation between ptosis severity and levator muscle function.

DESIGN

Retrospective cohort study.

METHODS

The medical records of 136 patients (53 men and 83 women; mean age, 67 years) with acquired blepharoptosis were reviewed for levator function (LF), margin reflex distance (MRD), age, and gender. Multivariate linear regression was performed for statistical analysis.

RESULTS

A significant correlation (P < .001) was seen between MRD (mean, 1.0 + 1.0 mm; range, -3.0 to 3.0 mm) and LF (mean, 15.0 + 1.0 mm; range, 11.0 to 20.0 mm). On average, a 0.5-mm reduction in LF was observed for each 1.0-mm decrease in MRD. This was independent to other variables assessed.

CONCLUSIONS

In patients with involutional blepharoptosis, a directly proportional decrease in levator function and eyelid height was observed. This may implicate an abnormality of the levator muscle itself as a contributing factor in the development of involutional blepharoptosis.

The significance of intraoperative measurements in acquired ptosis surgery

During a series of 101 levator procedures to correct acquired ptosis we measured the motility of the aponeurosis, the necessary advancement of the aponeurosis to adjust the eyelid height and the motility of Whitnall's ligament. We compared these intraoperative data with the data of the preoperative examination and did not find any correlation. The necessary amount of advancement of the aponeurosis to adjust the height of the eyelid was not related to the motility of the aponeurosis, the levator function or the amount of ptosis. However, we did find that the motility of Whitnall's ligament is closely related to the motility of the aponeurosis. Therefore connecting both structures is useful in ptosis adjustment without risking limited eyelid motility.

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.

Steroid-induced ptosis: case studies and histopathologic analysis

PURPOSE

The purpose of this study was to review patients who developed ptosis after subtenon's steroid injection and to study the mechanism of steroid-induced ptosis in an animal model.

METHODS

Part 1. Twenty-two patients with uveitis who had received posterior subtenon's triamcinolone acetonide injections were retrospectively reviewed. Demographics, type of uveitis, type and number of surgeries, pre and postoperative marginal reflex distance (MRD1), and clinical outcomes were evaluated. Part 2. Study of rabbit levator muscle and aponeurosis histopathology after subtenon's triamcinolone injection was performed.

RESULTS

Part 1. The average age was 44.6 years (range: 14-85 years) with a mean follow-up of 14 months. The most common causes of uveitis included uveitis after cataract extraction (five), pars planitis (three), multifocal choroiditis (three), and juvenile rheumatoid arthritis (three). The average time to documented onset of ptosis was 13.9 months (range: 0-49 months). In patients who received only one steroid injection, the average time to ptosis recorded was 2.7 months (range: 0-6 months). Seventeen patients underwent ptosis repair. Part 2. No ptosis was noted in the experimental and control groups. Histopathologic analysis of levator tissues revealed no significant difference in atrophy or degree of inflammation between experimental and control groups.

CONCLUSIONS

Ptosis following subtenon's steroid injection ranged from mild to moderate and occurred a few months after steroid injection. Prior studies of muscles and periocular tissues exposed to corticosteroids demonstrated degenerative muscle changes; our studies revealed no histopathologic changes in the levator muscle or aponeurosis.

Structural Abnormalities in the Levator Palpebrae Superioris Muscle in Patients With Congenital Blepharoptosis

BACKGROUND AND OBJECTIVE

To evaluate structural and ultrastructural abnormalities of the levator palpebrae superioris (LPS) complex in patients with congenital blepharoptosis.

PATIENTS AND METHODS

Samples of the LPS complex were obtained from patients operated on for congenital blepharoptosis between 2000 and 2001 and studied under light microscopy (15 cases) and electron microscopy (9 cases).

RESULTS

Findings of light microscopy evaluation of the LPS complex correlated closely with the clinical grading of congenital blepharoptosis-hypoplasia, decreased number and varying diameter of muscle fibers, and fibrous tissue hyperplasia in the endomysium and perimysium. The Müller's muscle preserved a normal appearance. Mild blepharoptosis revealed proliferation of collagen fibers on electron microscopy. Moderate blepharoptosis showed abnormal distribution of myofibrils and distortion of the tubular system and mitochondria in addition to the changes observed in mild blepharoptosis. Severe blepharoptosis showed mitochondria loss, cytoplasm thinning, and homogenous fiber areas in addition to the changes observed in mild and moderate blepharoptosis.

CONCLUSIONS

The clinical degree of severity of congenital blepharoptosis correlates positively with the degree of histopathologic changes in the levator palpebrae superioris muscle.

Histopathology of blepharoptosis induced by prolonged hard contact lens wear

PURPOSE

To clarify histopathologically the structural features of blepharoptosis in prolonged hard contact lens wearers.

DESIGN

Retrospective case-control study.

METHODS

Biopsy specimens from identical sites at the levator aponeurosis and Mueller muscle from 15 long-term hard contact lens wearers were examined histopathologically (group 1). They comprised two men and 13 women with bilateral blepharoptosis ranging in age from 26 to 59 years (mean +/- SD, 44.4 +/- 10.70 years). The average length of hard contact lens wear was 25.4 years (range 12 to 40 years), and the average spherical equivalent refractive error was -9.100 diopters (range -2.825 to -20.375 diopters). We also examined specimens from 15 patients with involutional blepharoptosis who underwent levator resection; they comprised three men and 12 women ranging in age from 64 to 79 years (mean +/- SD, 72.3 +/- 4.38 years).

RESULTS

All patients in group 1 manifested fibrosis and negligible fatty degeneration in Mueller muscle. In group 2, we detected mild fibrosis in Mueller muscle and fatty degeneration of the aponeurosis and Mueller muscle.

CONCLUSIONS

Prolonged hard contact lens wear induces fibrosis in Mueller muscle and may result in contact lens-induced blepharoptosis.

Efferent and afferent innervations of Mueller's muscle related to involuntary contraction of the levator muscle: important for avoiding injury during eyelid surgery

Because stretching of Mueller's muscle induces involuntary contraction of the levator muscle, we hypothesised that Mueller's muscle functions as a serial kind of muscle spindle of the levator muscle. To confirm the presence and location of efferent and afferent innervations of Mueller's muscle, cadavers' eyelids were microscopically and macroscopically examined, and the resultant findings were physiologically confirmed in patients' eyelids during surgery. Fine neural myelinated structures acting as a mechanoreceptor were found in the proximal Mueller's muscle. Mueller's muscle is doubly innervated by the unmyelinated sympathetic efferent nerve and the myelinated trigeminal proprioceptive afferent nerve, both of which run transversely on the proximal Mueller's muscle to join the lacrimal nerve. Electrical stimulation of the transverse nerve fibres induced involuntary contraction of both the levator muscle as the Hoffmann reflex and Mueller's muscle. Surgical injury to these nerve fibres should be avoided to preserve involuntary contraction of the levator muscle.

The cynomolgus monkey eyelid as an anatomic model for oculoplastic surgery

PURPOSE

To investigate the Cynomolgus monkey eyelid as an experimental model for oculoplastic surgery

METHODS

Eyelid and periocular tissue were removed from Cynomolgus monkeys being euthanized. After fixation, the macroscopic and microscopic characteristics of the Cynomolgus monkey eyelid were studied.

RESULTS

Macroscopic and microscopic characteristics of the Cynomolgus monkey eyelids were described. The Cynomolgus monkey eyelid bears resemblance to the human eyelid in its compartmentalization and complexity.

CONCLUSIONS

The Cynomolgus monkey eyelid is a suitable experimental research model. Its compartmentalization resembles that of the human eyelid both microscopically and macroscopically.

A histologic analysis and three-dimensional reconstruction of the muscle of Riolan

PURPOSE

To describe the anatomic and histologic relations of the muscle of Riolan in the eyelid margin.

METHODS

Serial microscopic sections of the eyelid were prepared, digitally scanned, and then reconstructed with computer software to create a 3-dimensional profile of this muscle group in two planes.

RESULTS

The muscle of Riolan is a distinct subdivision of striated muscle that is separate from the pretarsal orbicularis muscle. In parasagittal eyelid sections, the muscle appears to be composed of two separate bundles, the pars ciliaris, located anterior to the tarsal plate, and a second smaller bundle, the pars subtarsalis, located posterior to the orifices of the meibomian glands. Coronal sections, however, demonstrate numerous muscle fibers that traverse the tarsus, connecting the two muscle groups that we describe for the first time as the pars fascicularis.

CONCLUSIONS

The three muscle subdivisions are therefore physically joined together and appear to act as a single functional entity that should be collectively referred to as the muscle of Riolan.

Decreased tear expression with an abnormal Schirmer's test following botulinum toxin type A for the treatment of lateral canthal rhytides

BACKGROUND

Inactivation of muscles of facial expression by chemodenervation with botulinum toxin remains an off-label indication. Nevertheless, it continues to be a safe and effective technique to improve dynamic rhytides and is the treatment of choice for the hypertrophic lateral fibers of the orbicularis oculi muscle that can cause the superimposed crow's feet.

OBJECTIVE

Although infrequent and self-limiting, the complication of unexpected muscle weakness from toxin diffusion or erroneous placement is documented.

METHODS

However, injection into the pretarsal portion of the orbicularis oculi muscle resulting in unilateral ocular irritation and diminished tear expression as evidenced by a dry eye and an abnormal Schirmer's test has rarely been reported. Direct injection into the pretarsal fibers of the muscle as opposed to diffusion of the toxin into the muscle fibers or the lacrimal gland was consistent with the onset of action of the toxin and the prolonged duration of the ocular symptoms.

RESULTS

Treatment consisted of ocular lubrication until the effects of the toxin dissipated and muscle tone returned. Subsequent treatment did not result in a result in a recurrence of adverse sequelae.

CONCLUSIONS

Facial muscles are small, not isolated, and often have fibers that interdigitate. An important factor in the administration of botulinum toxin is the identification of the muscles responsible for the corresponding rhytide. Precise knowledge of muscular anatomy and function will aid in minimizing this and other potential complications.

Clinicopathologic evaluation of the Mueller muscle in thyroid-associated orbitopathy

PURPOSE

To study the histopathologic features of the Mueller muscle in chronic eyelid retraction caused by thyroid-associated orbitopathy. To investigate if the degree of eyelid retraction correlates with any histopathologic finding.

METHODS

A prospective case series of 23 consecutive patients with thyroid-associated orbitopathy was studied. Specimens were obtained during a standard muellerectomy. Formalin-preserved specimens were studied with the use of hematoxylin-eosin, periodic acid-Schiff, Masson trichrome, and Giemsa stains. Immunostaining against leukocyte common antigen, L26, CD3, and KP-1 was performed. Three control specimens were also evaluated in a similar fashion. Fresh tissue was placed in cold glutaraldehyde overnight, postfixed, dehydrated, and infiltrated with epoxy resin. Silver (70 nm) sections were cut and stained with uranyl acetate and lead citrate for electron microscopic examination.

RESULTS

On light microscopy, fibrosis and mast cell infiltration was present in all 23 specimens. Fat infiltration was noted in 16 of 23 specimens and did not correlate with increasing age of the patient. Interstitial edema and lymphocytic infiltration were not observed. On immunohistochemistry, leukocyte common antigen was positive, confirming the presence of inflammation. L26, CD3, and KP1 were negative. Electron microscopy demonstrated fibrosis, mast cells, and abundant contracting Mueller cells. The degree of clinical retraction in millimeters did not correlate with fibrosis, inflammation, or fat infiltration. The control specimens demonstrated rare fat and mast cell infiltration and no fibrosis.

CONCLUSIONS

Contrary to previous reports, the Mueller muscle is involved in the inflammation and fibrosis that characterizes thyroid-associated orbitopathy. The Mueller muscle is grossly enlarged. On histopathologic inspection, fibrosis, fatty infiltration, and increased mast cell presence accompany focal atrophy of the Mueller muscle. In concordance with prior descriptions, many Mueller cells are in an actively contracting state on electron microscopy.