Attracting medical school graduates to residency programs in remotely located hospitals: the challenge lies beyond financial incentives.

BACKGROUND: Recruitment to residency programs in hospitals located in other than major hubs ("remotely located") is a challenge in many countries. In 2011, the Israeli Ministry of Health launched a 10-year financial incentive to encourage physicians to enroll in residency programs in such hospitals. Nearly 1 billion New Israeli Shekels (260 million US$) were invested in that program which had only limited success. As a new physician association's collective agreement is impending, we aimed to measure the effectiveness of selected incentives in attracting medical school graduates to residencies in remotely located hospitals. METHODS: This study included Israeli medical students in their final year of medical school. We used an online questionnaire with multiple-choice demographic questions and a 5-point Likert scale to gauge the effect of various incentives on their preference for residency location. RESULTS: Between July and November 2022, 522 students responded (405 studied in Israeli medical schools [out of 705 students] and 117 in foreign medical schools [out of 1936 students]). Forty-two percent had at least one clerkship in a remotely located hospital, and 24% had included at least one remotely located hospital among their top five choices for internship. Only 13% reported that they prefer a residency program in those institutions. The incentive selected by students as most persuasive was government assistance in acceptance to and financial support for a fellowship abroad, followed by a financial grant and fewer on-call hours. Only 7% of the students indicated that no incentive would influence them to choose a remotely located hospital for their residency training. Medical education in a remotely located university and the choice of at least one remotely located hospital among the top five choices for internship were significantly associated with positive incentive receptivity, whereas male sex and older age were associated with negative receptivity. CONCLUSION: This study on the attitudes of Israeli medical school graduates toward incentives aimed at attracting them to residencies in remotely located institutions revealed that career development opportunities and assistance in obtaining fellowships might influence their choice.

Reoperation for congenital ptosis: characteristics, success rates, and predicting factors.

OBJECTIVE: Reoperation for congenital ptosis has added morbidity. The purpose of the current study was to examine the risk for redo ptosis surgery in patients with congenital ptosis, as well as to find predictive factors for reoperation. METHODS: This is a retrospective, cohort study. Analysis of all patients with congenital ptosis who underwent their first ptosis correction surgery between 2012 and 2021 at Sheba Medical Center was performed. RESULTS: Sixty patients (36 male and 24 female) underwent ptosis surgery for congenital ptosis Twenty nine patients (48.33%) underwent frontalis sling (FS), 13 patients (21.67%) underwent levator muscle (LM) surgeries, 9 patients received levator resection (LR), 4 patients received external levator advancement (LAA), and 18 patients (30%) underwent Müller's muscle-conjunctival resection (MMCR). Eighteen patients (30%) underwent a second ptosis surgery. The unadjusted risk of second ptosis surgery was almost four-fold among males with ptosis relative to females with ptosis (HR, 3.90; 95% CI, 3.67-547; p = 0.033) and higher among younger individuals (HR, 4.23; 95% CI, 3.33-5.62; p = 0.042). Older age was protective against the risk of second ptosis surgery (adjusted OR, 0.50; 95% CI, 0.21-0.60; p < 0.001), whereas male sex was associated with an increased likelihood of second ptosis surgery (adjusted OR, 3.33; 95% CI, 1.64-3.98; p < 0.001). CONCLUSIONS: An increased risk of failure of the first surgery was found among male patients, younger patients, and patients with more severe ptosis before the first surgery. Awareness of those factors is beneficial for clinicians and parents.

Computer-aided diagnosis of eyelid skin tumors using machine learning.

OBJECTIVE: To develop an automated, new framework based on machine learning to diagnose malignant eyelid skin tumors. METHODS: This study used eyelid lesion images from Sheba Medical Center, a large tertiary center in Israel. Before model training, we pretrained our models on the International Skin Imaging Collaboration (ISIC) 2019 dataset consisting of 25,332 images. The proprietary eyelid data set was then used for fine-tuning. The data set contained multiple images per patient, aiming to classify malignant lesions in comparison to benign counterparts. RESULTS: The analyzed data set consisted of images representing both benign and malignant eyelid lesions. For the benign category, a total of 373 images were sourced. By comparison, for the malignant category, 186 images were sourced. For the final model, at sensitivity of 93.8% (95% CI 80.0-100.0%), the model has a corresponding specificity of 73.7% (95% CI 60.0-87.1%). To further understand the decision-making process of our model, we employed heatmap visualization techniques, specifically gradient-weighted Class Activation Mapping. DISCUSSION: This study introduces a dependable model-aided diagnostic technology for assessing eyelid skin lesions. The model demonstrated accuracy comparable to human evaluation, effectively determining whether a lesion raises a high suspicion of malignancy or is benign. Such a model has the potential to alleviate the burden on the health care system, particularly benefiting rural areas, and enhancing the efficiency of clinicians and overall health care.

Pre-Operative Planning of a DCR Surgery Using Virtual Reality.

PURPOSE: To assess a novel Virtual Reality (VR) tool designed to enhance understanding of the nasal anatomy in patients eligible for DCR surgery. METHODS: Preoperative Computed Tomography (CT) scans of the orbit were obtained and loaded as DICOM (Digital Imaging and Communications in Medicine) files onto the D2P software (3D Systems Inc. Littleton, CO) for tissue segmentation and 3D model preparation. Segmentation was performed on several anatomical structures, including the skull, lacrimal sac, nasal septum, inferior and middle turbinate. The resulting 3D model was visualized using a VR headset. After completing the segmentation procedure, ten cases were evaluated by a panel of six surgeons, including both senior and resident physicians from ENT and oculoplastic specialties. RESULTS: The dataset under examination comprised images from 10 preoperative CT scans of the orbits of patients eligible for Endo-DCR. When evaluating the CT using the VR tool, in 73.3% of the cases ENT surgeons were right about the side of pathology, while only 43.3% ophthalmologists were right (chi-square, p = .018). In 72.8% of the cases ENT surgeons were evaluated right that there is a septum deviation, while only in 47.2% of the cases the ophthalmologists were right (chi-square, p = .094).When evaluating the CT using the VR tool, in 60% of the cases consultants were right about the pathology, while 57.7% of the residents were right (chi-square, p = .853). In 81.7% of the cases consultants were evaluated right that there is a septum deviation, while only in 58.3% of the cases the ophthalmologists were right (chi-square, p = .198). DISCUSSION: ENT surgeons, as well as consultants, interpreted the CT better than the ophthalmologists and residents. Surprisingly, the VR system did not help them to interpret the CT better. Further, more extensive studies should be done to build a VR system that assists in the correct interpretation of the preoperative CT before DCR surgery as well as during DCR surgery.

Ocular manifestations and outcomes of OPMD- a report from the national IsrOPMD registry.

PURPOSE: This study aims to describe the ocular manifestations, treatment, and prognosis of OPMD patients registered in the national Israel OPMD(IsrOPMD) registry. METHODS: Data was prospectively collected from patients referred to the IsrOPMD registry from January 2022 to March 2023. This included patient demographics, medical and ocular history, eye exams, eyelid evaluations, visual field exams, and orthoptic evaluations. RESULTS: 30 patients (15 males, mean age 53 years) were treated in the ocular OPMD clinic, predominantly of Bukhari descent (86.6%). The mean visual acuity was 0.06 logMAR. Twenty-one patients (70%) had eye movement problem, mostly in horizontal gaze. 6(20%) patients' complaint about diplopia. Ptosis surgery was performed in 21(70%) patients, with 17(56.7%) patients underwent frontalis sling surgery and 4(13.3%) patients undergoing levator advancement. The mean Margin reflex distance (MRD1) improved post-surgery (2.28 mm vs. 1.58 mm), but 11(36.6%) patients required more than one ptosis surgery. CONCLUSIONS: The study contributes valuable insights into the ocular aspects of OPMD. It reveals that OPMD patients often experience a range of ocular symptoms, such as ptosis, abnormalities in eye movements, strabismus, and potentially diplopia, which can significantly impact their quality of life. The findings underscore the importance of regular ophthalmological follow-up for these patients to address these symptoms effectively. The study is significant in contributing to the limited but growing knowledge about the ocular manifestations of OPMD and the management of these symptoms to improve the quality of life for patients suffering from this condition.

How to assess blepharoptosis via telemedicine: method and its reliability.

PURPOSE: To report the method to assess belpahroptosis and its reliability of adult ptosis using video consultation. METHODS: This is a retrospective, comparative, case series. The surgical waiting list for ptosis surgery between 8/2020 and 1/2021 was checked and only cases listed for surgery via video consultation assessment, without any previous face-to-face consultation, were included. The following data were collected for patients who underwent video consultation before surgery: Demographic data, level of experience of clinician, levator function, Cogan's twitch sign, fatigability test, eye motility, presence of lagophthalmos, clinical history to rule out Myasthenia Gravis, other myopathies or Horner syndrome, whether the surgery was performed or canceled, reason for cancellation, date of surgery, type of procedure and surgeon experience. RESULTS: A total of 176 patients underwent ptosis surgery. From those, 45 patients (25.6%) had only video assessment prior to surgery, 36 patients (80%) eventually underwent ptosis surgery. Surgery was canceled in 20% of the cases: in 2 cases (4.44%) due to misdiagnosis of ptosis during video consultation, confirmed on the day of surgery during pre-surgical face-to-face assessment; the other 7 cases (15.55%) belpharoptosis was confirmed on face-to-face examination but the surgery was canceled due to other reasons. The diagnosis of ptosis assessment via video consultation was corrected in 43 cases (95%) (p_value = 0.156, chi_ square). The accuracy of ptosis diagnosis was 13 out of 15 (86.7%) by fellow assessments and 30 out of 30 (100%) by consultant assessments (p_value = 0.041, chi_ square). In most of the cases ptosis assessment in video consultation included: rough judgment of levator function, eye motility and checking signs of lagophthalmos. CONCLUSIONS: Video consultation is an efficient and reliable way to assess patients with ptosis, with 95% of reliability. Although a thorough ptosis assessment is advised, there was no difference between the accuracy of diagnosis on those who did not have the full suggested assessment.

Prevalence of common and rare ophthalmic findings in adults attending a medical survey institute.

PURPOSE: To examine the ophthalmic data from a large database of people attending a general medical survey institute, and to investigate ophthalmic findings of the eye and its adnexa, including differences in age and sex. METHODS: Retrospective analysis including medical data of all consecutive individuals whose ophthalmic data and the prevalences of ocular pathologies were extracted from a very large database of subjects examined at a single general medical survey institute. RESULTS: Data were derived from 184,589 visits of 3676 patients (mean age 52 years, 68% males). The prevalence of the following eye pathologies were extracted. Eyelids: blepharitis (n = 4885, 13.3%), dermatochalasis (n = 4666, 12.7%), ptosis (n = 677, 1.8%), ectropion (n = 73, 0.2%), and xanthelasma (n = 160, 0.4%). Anterior segment: pinguecula (n = 3368, 9.2%), pterygium (n = 852, 2.3%), and cataract or pseudophakia (n = 9381, 27.1%). Cataract type (percentage of all phakic patients): nuclear sclerosis (n = 8908, 24.2%), posterior subcapsular (n = 846, 2.3%), and capsular anterior (n = 781, 2.1%). Pseudophakia was recorded for 697 patients (4.6%), and posterior subcapsular opacification for 229 (0.6%) patients. Optic nerve head (ONH): peripapillary atrophy (n = 4947, 13.5%), tilted disc (n = 3344, 9.1%), temporal slope (n = 410, 1.1%), ONH notch (n = 61, 0.2%), myelinated nerve fiber layer (n = 94, 0.3%), ONH drusen (n = 37, 0.1%), optic pit (n = 3, 0.0%), and ON coloboma (n = 4, 0.0%). Most pathologies were more common in males except for ONH, and most pathologies demonstrated a higher prevalence with increasing age. CONCLUSIONS: Normal ophthalmic data and the prevalences of ocular pathologies were extracted from a very large database of subjects seen at a single medical survey institute.

Effects of photoperiod and food on glucose intolerance and subsequent ocular pathology in the fat sand rat.

Type 2 diabetes mellitus (T2DM) and its ocular complications, such as cataract and diabetic retinopathy (DR) have been linked to circadian rhythm-disturbances. Using a unique diurnal animal model, the sand rat (Psammomys obesus) we examined the effect of circadian disruption by short photoperiod acclimation on the development of T2DM and related ocular pathologies. We experimented with 48 male sand rats. Variables were day length (short photoperiod, SP, vs. neutral photoperiod NP) and diet (standard rodent diet vs. low-energy diet). Blood glucose, the presence of cataract and retinal pathology were monitored. Histological slides were examined for lens opacity, retinal cell count and thickness. Animals under SP and fed standard rodent diet (SPSR) for 20 weeks had higher baseline blood glucose levels and lower glucose tolerance compared with animals kept under NP regardless of diet, and under SP with low energy diet (SPLE). Animals under SPSR had less cells in the outer nuclear layer, a lower total number of cells in the retina, and a thickened retina. Higher blood glucose levels correlated with lower number of cells in all cellular layers of the retina and thicker retina. Animals under SPSR had higher occurrence of cataract, and a higher degree of cataract, which correlated with higher blood glucose levels. Sand rats kept under SPSR develop cataract and retinal abnormalities indicative of DR, whereas sand rats kept under NP regardless of diet, or under SPLE, do not. These ocular abnormalities significantly correlate with hyperglycemia.

The Long-Term Effect on Dry Eye of Posterior Approach Ptosis Surgery Vs. Upper Eyelid Blepharoplasty.

PURPOSE: To examine the long-term effect of combined blepharoplasty and Müller muscle-conjunctival resection (MMCR) compared to an upper blepharoplasty procedure on dry eye syndrome. METHODS: This is a Prospective comparative case series. Two groups of patients participated in this study: the blepharoplasty group included adult patients that underwent blepharoplasty at least 3 years earlier and the ptosis group consisting of adult patients that underwent MMCR with blepharoplasty at least 3 years earlier. The parameters that were compared for all patients before the procedure, on postoperative day 90, and at the long-term follow-up were: Schirmer-test 2, tear break-up time (TBUT), fluorescein staining, and lissamine green (LG) staining. RESULTS: The participants included 25 post-MMCR patients with a mean follow-up of 4.94 ± 0.64 years and 15 post-blepharoplasty patients with a mean follow-up of 4.22 ± 0.32 years. There was a significant increase in the postoperative LG and fluorescein staining scores compared to the preoperative scores in the ptosis group (p < .01 and p < .01, respectively) as well as a decrease in postoperative TBUT compared to the preoperative values (p = .044). Those parameters were not significant in the blepharoplasty group. CONCLUSIONS: Patients who underwent MMCR, but not those following upper blepharoplasty, showed signs of dry eye compared to the preoperative status after long-term follow-up. Dry eye signs should be examined before MMCR surgery, and patients should be aware of the high risk of developing dry eye and the need for long-term treatment. Surgeons should carefully consider performing MMCR for patients with severe dry eye.

Blepharoptosis and cognitive performance: a population-based study of 1.4 million adolescents.

The purpose of this study is to examine the association between blepharoptosis and cognitive performance in late adolescence. This population-based, retrospective, cross-sectional study included 1,411,570 Israeli-born adolescents (620,107 women, 43.9%) aged 16-19 years who were medically examined before compulsory military service between 1993 and 2017. The diagnosis of blepharoptosis was verified by an ophthalmologist. Cognitive performance was assessed by a validated intelligence-quotient-equivalent test, comprising four domains (problem-solving, verbal abstraction and categorization, verbal comprehension, and mathematical abilities). Cognitive Z-scores were calculated and categorized as high (≥ 1 standard deviation (SD)), medium (- 1 to < 1 SD), and low (less than - 1 SD). Relationships were analyzed using regression models adjusted for sociodemographic variables including sex, year of birth, residential socioeconomic status, education level, body mass index, and familial country of origin. A total of 577 (41 per 100,000, 32.2% women) adolescents were diagnosed with blepharoptosis. The proportions of unilateral and bilateral visual impairment among adolescents with blepharoptosis were 13.0% and 3.5%, respectively. In a multivariable analysis, blepharoptosis was associated with a 0.18 SD reduction in cognitive Z-score (p < 0.001). The adjusted odds ratios for low and high cognitive Z-scores in adolescents with blepharoptosis were 1.54 (1.25-1.89) and 0.80 (0.62-1.04), respectively. This relationship persisted when adolescents with normal best-corrected visual acuity or unimpaired health status were analyzed separately.  Conclusions: Blepharoptosis is associated with reduced cognitive performance determined in late adolescence. Future prospective studies should investigate the causes of this link and their underlying mechanisms. What is Known: • While earlier investigations have examined the effects of blepharoptosis on vision and quality of life, the association between blepharoptosis and cognitive outcomes in youth has remained unexplored. What is New: • This nationwide study involving 1.4 million Israeli adolescents found a correlation between blepharoptosis and reduced cognitive performance. • Our findings suggest a potential interplay between blepharoptosis and cognitive development in the pediatric population, calling for increased focus on the educational needs of affected individuals.

The Outcomes of Involutional Ptosis Surgeries in a Single Tertiary Center.

PURPOSE: To report the surgical outcome of anterior approach primary ptosis surgery in a tertiary center and to compare redo surgical rates between different grades of surgeons. METHODS: This is a Retrospective review of series of annual audits. All involutional/aponeurosis-disinsertion ptosis surgeries performed at Moorfields Eye-hospital (MEH) between January 01, 2016 and December 31, 2019 were included. Only primary surgery was included. The following data were collected; number of surgeries per year, number of patients, demographics data, grades of surgeons, success rate, redo surgery rate from different grades of surgeons, complications rate and patients' satisfaction. RESULTS: During the study period, 1191 ptosis surgery were performed, with 899 (75%) cases being involutional/aponeurosis-disinsertion ptosis. The mean redo surgery rate within one year from the primary surgery was 10.5% and the mean complication rate was 1.0%, with 78.95% of patients reported being satisfied with the results of the surgery, having no difference between surgeon's grades. The redo surgery rate was higher for cases performed by a junior surgeon (fellow/registrar) (64.26%) than by a consultant (38.94%). CONCLUSIONS: We report the success rate of a large cohort of primary involutional ptosis surgery performed at the ophthalmic-specialist tertiary center. The success and complication rates are comparable to the literature at 90% and 1%, respectively. Redo surgeries were more frequently required when performed by junior surgeons compared to the consultants, whereas the patient satisfaction level did not differ between different grades of surgeons.

Elevated serum thyroid stimulating immunoglobulin linked to failure of first-line intravenous methylprednisolone monotherapy in moderate-to-severe thyroid eye disease.

PURPOSE: To assess factors associated with failure of intravenous methylprednisolone (IVMP) monotherapy as the first-line treatment for thyroid eye disease (TED) and to identify patients who might benefit from supplementing mycophenolate mofetil (MMF) to IVMP. METHODS: Data for all patients with TED treated with IVMP according to the EUGOGO protocol in our center between 2016-2021 were retrospectively analysed. RESULTS: Forty-seven patients (mean age 51.32 ± 14 years, 27 females) were enrolled. The mean time from first reported symptoms to first IVMP treatment was 12.1 ± 5.59 months (range 0-120). The mean clinical activity score (CAS) before treatment and at a mean of 5 and 12.2 weeks after treatment initiation was 6.00, 2.96, and 1.81, respectively (P < 0.01). Twenty-one patients (44.68%) were recommended second-line treatment: nine due to no response or worsening of CAS, six due to partial response, four with good response but early relapse after completion of treatment, and one due to late relapse. Eighteen of those 21 patients received second-line treatment which included rituximab (n = 7), MMF (n = 6), a second course of IVMP (n = 4), and tocilizumab (n = 1). Serum thyroid-stimulating immunoglobulin (TSI) levels were higher in patients who received second-line treatment compared with patients who responded well to first-line IVMP monotherapy at presentation (2135% vs 1159%, P = 0.05) and after completion of first-line treatment (2201% vs. 986%, P = 0.043). DISCUSSION: TED patients requiring second-line treatment after failed IVMP monotherapy had higher baseline and post-first-line treatment serum TSI levels. Those with elevated TSI may benefit from dual therapy (IVMP and MMF) and require closer monitoring.

Glaucoma Prediction Models Based on Ocular and Systemic Findings.

INTRODUCTION: Our aim was to explore the impact of various systemic and ocular findings on predicting the development of glaucoma. METHODS: Medical records of 37,692 consecutive patients examined at a single medical center between 2001 and 2020 were analyzed using machine learning algorithms. Systemic and ocular features were included. Univariate and multivariate analyses followed by CatBoost and Light gradient-boosting machine prediction models were performed. Main outcome measures were systemic and ocular features associated with progression to glaucoma. RESULTS: A total of 7,880 patients (mean age 54.7 ± 12.6 years, 5,520 males [70.1%]) were included in a 3-year prediction model, and 314 patients (3.98%) had a final diagnosis of glaucoma. The combined model included 185 systemic and 42 ocular findings, and reached an ROC AUC of 0.84. The associated features were intraocular pressure (48.6%), cup-to-disk ratio (22.7%), age (8.6%), mean corpuscular volume (MCV) of red blood cell trend (5.2%), urinary system disease (3.3%), MCV (2.6%), creatinine level trend (2.1%), monocyte count trend (1.7%), ergometry metabolic equivalent task score (1.7%), dyslipidemia duration (1.6%), prostate-specific antigen level (1.2%), and musculoskeletal disease duration (0.5%). The ocular prediction model reached an ROC AUC of 0.86. Additional features included were age-related macular degeneration (10.0%), anterior capsular cataract (3.3%), visual acuity (2.0%), and peripapillary atrophy (1.3%). CONCLUSIONS: Ocular and combined systemic-ocular models can strongly predict the development of glaucoma in the forthcoming 3 years. Novel progression indicators may include anterior subcapsular cataracts, urinary disorders, and complete blood test results (mainly increased MCV and monocyte count).

Ocular Surface Temperature Profile of Eyes with Retinal Vein Occlusion.

Retinal vein occlusion (RVO) results in ischemia followed by an inflammatory response. Both processes affect tissue temperature in opposite directions. Here, we evaluate the effect of RVO on the ocular surface temperature (OST) profile. Subjects with RVO were prospectively recruited. Healthy subjects without any ocular disease served as controls. The OST was determined using the Therm-App thermal imaging camera, and image processing software was employed to compute the mean temperature values of the medial canthus, lateral canthus, and cornea. We obtained thermographic images from 30 RVO subjects (30 eyes) and 148 controls (148 eyes). A univariate analysis found that eyes with RVO had significantly elevated OSTs compared to the controls (mean difference of 0.6 ± 0.3 Celsius, p < 0.05). However, this distinction between the groups lost statistical significance upon adjusting for possible confounders, including patient and environmental factors. These findings were confirmed with a post hoc case-control matched comparison. In conclusion, RVO does not seem to affect the OST. This might be due to the balance between inflammatory thermogenesis and heat constriction from ischemia in RVO. It is also possible that, in our cohort, the RVO pathophysiological processes involved were localized and did not extend to the anterior segment. Patient and environmental factors must be considered when interpreting the OST.

Big Data Analysis of Glaucoma Prevalence in Israel.

PRCIS: The prevalence of glaucoma in the adult population included in this study was 2.3%. Normal values of routine eye examinations are provided including age and sex variations. PURPOSE: The purpose of this study was to analyze the prevalence of glaucoma in a very large database. METHODS: Retrospective analysis of medical records of patients examined at the Medical Survey Institute of a tertiary care university referral center between 2001 and 2020. A natural language process (NLP) algorithm identified patients with a diagnosis of glaucoma. The main outcome measures included the prevalence and age distribution of glaucoma. The secondary outcome measures included the prevalence and distribution of visual acuity (VA), intraocular pressure (IOP), and cup-to-disc ratio (CDR). RESULTS: Data were derived from 184,589 visits of 36,762 patients (mean age: 52 y, 68% males). The NLP model was highly sensitive in identifying glaucoma, achieving an accuracy of 94.98% (area under the curve=93.85%), and 633 of 27,517 patients (2.3%) were diagnosed as having glaucoma with increasing prevalence in older age. The mean VA was 20/21, IOP 14.4±2.84 mm Hg, and CDR 0.28±0.16, higher in males. The VA decreased with age, while the IOP and CDR increased with age. CONCLUSIONS: The prevalence of glaucoma in the adult population included in this study was 2.3%. Normal values of routine eye examinations are provided including age and sex variations. We proved the validity and accuracy of the NLP model in identifying glaucoma.

Müller's Muscle as a Sensory Proprioceptive Organ: Histological and Histochemical Analysis.

Purpose: The purpose of this study was to determine whether proprioceptive nerves are present in Müller's muscle. Methods: This was a prospective cohort study in which histologic and immunofluorescence analyses of excised Müller's muscle specimens were performed. Twenty fresh Müller's muscle's specimens from patients undergoing posterior approach ptosis surgery in one center between 2017 and 2018 were evaluated by histologic and immunofluorescent analysis. Axonal types were determined by measuring axon diameter in methylene blue stained plastic sections and by immunofluorescence of frozen sections. Results: We identified large (greater than 10 microns) and small myelinated fibers in the Müller's muscle, with 6.4% of these fibers being large. Immunofluorescent labeling with choline acetyltransferase showed no evidence of skeletal motor axons in the samples, indicating large axons are likely to be sensory and proprioceptive. In addition, we identified C-fibers using double labeling with peripherin and neural cell adhesion molecules. Conclusions: Overall, large myelinated sensory fibers are present in the Müller's muscle, likely serving proprioceptive innervation. This suggests that proprioception signals from Müller's muscle may have a role in eyelid spatial positioning and retracting, in addition to visual deprivation. This finding sheds new light on our understanding of this complex mechanism.