Ocular Motility Research Articles

Evaluation of Subjective Visual Vertical (SVV) and Ocular Movements in Patients with Primary headache -An Analytical Cross-sectional Study

Evaluation of Subjective Visual Vertical (SVV) and Ocular Movements in Patients with Primary headache -An Analytical Cross-sectional Study

SRPK3 Is Essential for Cognitive and Ocular Development in Humans and Zebrafish, Explaining X-Linked Intellectual Disability.

Intellectual disability is often the outcome of neurodevelopmental disorders and is characterized by significant impairments in intellectual and adaptive functioning. X-linked intellectual disability (XLID) is a subset of these disorders caused by genetic defects on the X chromosome, affecting about 2 out of 1,000 males. In syndromic form, it leads to a broad range of cognitive, behavioral, ocular, and physical disabilities. Employing exome or genome sequencing, here we identified 4 missense variants (c.475C > G; p.H159D, c.1373C > A; p.T458N, and c.1585G > A; p.E529K, c.953C > T; p.S318L) and a putative truncating variant (c.1413_1414del; p.Y471*) in the SRPK3 gene in 9 XLID patients from 5 unrelated families. To validate SRPK3 as a novel XLID gene, we established a knockout (KO) model of the SRPK3 orthologue in zebrafish. The 8 patients ascertained postnatally shared common clinical features including intellectual disability, agenesis of the corpus callosum, abnormal eye movement, and ataxia. A ninth case, ascertained prenatally, had a complex structural brain phenotype. Together, these data indicate a pathological role of SRPK3 in neurodevelopmental disorders. In post-fertilization day 5 larvae (free swimming stage), KO zebrafish exhibited severe deficits in eye movement and swim bladder inflation, mimicking uncontrolled ocular movement and physical clumsiness observed in human patients. In adult KO zebrafish, cerebellar agenesis and behavioral abnormalities were observed, recapitulating human phenotypes of cerebellar atrophy and intellectual disability. Overall, these results suggest a crucial role of SRPK3 in the pathogenesis of syndromic X-linked intellectual disability and provide new insights into brain development, cognitive and ocular dysfunction in both humans and zebrafish. ANN NEUROL 2024;96:914-931.

Systematic review of cognitive impairment in drivers through mental workload using physiological measures of heart rate variability

The intricate interplay between driver cognitive dysfunction, mental workload (MWL), and heart rate variability (HRV) provides a captivating avenue for investigation within the domain of transportation safety studies. This article provides a systematic review and examines cognitive hindrance stemming from mental workload and heart rate variability. It scrutinizes the mental workload experienced by drivers by leveraging data gleaned from prior studies that employed heart rate monitoring systems and eye tracking technology, thereby illuminating the correlation between cognitive impairment, mental workload, and physiological indicators such as heart rate and ocular movements. The investigation is grounded in the premise that the mental workload of drivers can be assessed through physiological cues, such as heart rate and eye movements. The study discovered that HRV and infrared (IR) measurements played a crucial role in evaluating fatigue and workload for skilled drivers. However, the study overlooked potential factors contributing to cognitive impairment in drivers and could benefit from incorporating alternative indicators of cognitive workload for deeper insights. Furthermore, investigated driving simulators demonstrated that an eco-safe driving Human-Machine Interface (HMI) significantly promoted safe driving behaviors without imposing excessive mental and visual workload on drivers. Recommendations were made for future studies to consider additional indicators of cognitive workload, such as subjective assessments or task performance metrics, for a more comprehensive understanding.

The association between asymmetric stress distribution on the lamina cribrosa and glaucoma progression.

The purpose of this study was to assess the effect of ocular movements on the progression of glaucoma. A total of 118 primary open-angle glaucoma patients were enrolled, comprising 71 patients in the progression group and 47 patients in the non-progression group. Utilizing three geometric parameters-axial length, optic disc radius, and optic cup deepening-a personalized virtual optic nerve head (ONH) model was designed. ONH biomechanical changes during ocular movement were simulated using a finite element analysis. Simulation results were analyzed and compared between the progression and non-progression groups. In both progression and non-progression groups, ONH strains significantly increased with increasing rotation angle. When the eye rotated by 10°, the stress on the anterior surface of the lamina cribrosa on the temporal side was significantly higher in the progression group compared to the non-progression group (16.19 ± 0.90kPa vs. 13.24 ± 3.00 kPa, P < 0.001). The stress ratio, indicating asymmetric stress distribution, was higher in the progression group than in the non-progression group (0.56 ± 0.13 vs. 0.49 ± 0.19, P = 0.018). Stress ratio significantly increased with increasing optic disc radius (standardized β = 0.303, P < 0.001) and optic cup deepening (standardized β = 0.538, P < 0.001). Asymmetric stress distribution with ocular movement was higher in the progression group. This asymmetry was associated with optic disc radius and optic cup deepening. Therefore, ocular movement may contribute to the progression of glaucoma, with ONH geometry playing a role. WHAT IS KNOWN : Ocular movement is considered one of the physical stress factors affecting the optic nerve head. Ocular movement increased the strain on the optic nerve head and resulted in an asymmetric stress distribution on the lamina cribrosa surface. Asymmetric stress distribution on lamina cribrosa with ocular movement was higher in the glaucoma progression group and associated with optic disc radius and optic cup deepening.

Case report: Orbital myeloid sarcoma: a report of two rare cases and review of the literature

Myeloid sarcoma (MS) occurs when primitive or naive myeloid cells form outside the bone marrow. It occurs mainly in soft/connective tissue and skin; orbital involvement is rare. We report the cases of two female adults, analyze the clinicopathologic characteristics, and review the literature. The average age of both patients was 28 years and they presented unilateral proptosis combined with varying degrees of impaired visual acuity and restricted ocular motility in the affected eye. Despite this, they maintained good overall health and no notable family history. However, the patients had no systemic clinical manifestations of acute myeloid leukemia (AML). Both patients underwent surgical resection of the orbital tumor. Immunohistochemistry showed positive staining for CD43, Leukocyte Common Antigen (LCA), and myeloperoxidase (MPO) and a high level of positive staining for Ki67, which were diagnostic for MS. Bone marrow cytology examination showed no apparent abnormalities. Postoperative chemotherapy, local radiotherapy, and allogeneic hematopoietic stem cell transplantation (allo-HSCT) were performed in Case 1, while the second patient underwent adjuvant chemotherapy and radiotherapy. No recurrence or metastasis was found in either patient during follow-up (one more than 5 years, the other more than 10 years). The occurrence of orbital MS is infrequent, with atypical clinical and imaging findings. The diagnosis depends on pathomorphology and immunohistochemical staining, and the prognosis is good with postoperative adjuvant chemotherapy, local radiotherapy, and allo-HSCT.

Utility of Clinical Features in Identifying Electrographic Seizures in Hospitalized Patients Admitted for Non-Neurological Diagnoses.

Electrographic seizures (ESz) are seizures without prominent motor activity diagnosed with electroencephalogram and are a common complication in critically ill patients with alterations of consciousness. Previous studies suggested clinical signs, including ocular movement abnormalities, facial/periorbital twitching, or remote seizure risk factors, are sensitive for presence of ESz. To assess the utility of clinical features in identifying ESz in critically ill patients with alterations of consciousness. This is a retrospective case-control study of 50 patients admitted to the University of North Carolina (UNC) Medical Center and UNC Rex Hospital. Inpatients older than 18 years old undergoing continuous video electroencephalogram (cEEG) were included. Patients admitted for neurologic diagnoses were excluded. A total of 25 patients with ESz (Sz-EEG) were matched with 25 controls by electroencephalogram duration ± 12 hours (No-Sz-EEG). Elements of patient's history and physical findings previously shown to be sensitive for presence of ESz were collected. Descriptive statistical analyses were used. Most patients were admitted to medical ICUs (72%; n = 36). There was no difference between groups in clinical findings previously shown to be sensitive for ESz. Positive and negative likelihood ratios for these findings generally fell between 1-2 and 0.5-1, respectively, indicating they are inaccurate predictors for ESz. Patients with ESz had significantly higher mortality (p = 0.012). Our matched case-control study showed that in the critically ill patient population hospitalized in tertiary care centers and admitted for non-neurologic primary diagnoses, incidence of ocular movement abnormalities, facial/periorbital twitching, and presence of remote risk factors for seizures had low predictive accuracy for ESz. However, these findings are not generalizable to patients with neurologic diseases or to other practice settings with different levels of access to cEEG. We concluded that in this exploratory analysis of hospitalized critically ill patients with non-neurologic diagnoses, these clinical signs did not reliably stratify risk for ESz on cEEG. However, further prospective studies are needed to better evaluate these conclusions.

Strabismus Screening Using Eyetracker Combined with Machine Learning

Purpose: To assess the effectiveness of an automated screening program that diagnoses horizontal strabismus using machine learning based on ocular deviation data captured by the wearable eyetracker, Tobii pro glasses 2 (TPG2).Methods: The TPG2 which locates the pupil center to measure ocular movement was used. In normal adults wearing TPG2, horizontal ocular deviation was induced by covering the left eye and applying prisms of varying strengths (2, 3, 4, 5, 6, 8, 10, 12, 15, 20, 25, 30, 35, and 40 PD base-in and out) to the right eye. TPG2 automatically recorded ocular deviation before and after prism induction generating 28 types of ocular deviation sets. From each set, 20 X-axis values before and after ocular deviation were randomly extracted using an oversampling technique creating a total of 61,600 ocular deviation sets. For training, 56,000 sets were used and 5,600 were evaluated for sensitivity, specificity, and area under the curve (AUC).Results: Eleven normal adults (5 males) participated with a mean age of 34.8 ± 7.37 years. Based on an 8 PD threshold, deviations of 8 PD or less demonstrated a sensitivity of 1.0, a specificity of 0.95, and an AUC of 0.97. When categorized into three groups based on 8 PD and 20 PD thresholds, the results were: sensitivity of 0.90 and specificity of 0.95 for ≤ 8 PD; sensitivity of 0.60 and specificity of 1.00 for 8-20 PD; sensitivity of 1.00 and specificity of 0.88 for &gt; 20 PD.Conclusions: The machine learning program developed using induced ocular deviations measured with prisms and TPG2 shows promise for use in future strabismus screening tests.

Orbital tuberculosis presenting as vision loss and headache: early management is paramount

Orbital tuberculosis is a rare form of extra pulmonary TB and may arise either by hematogenous route or spread directly from the paranasal sinus. We herein report two cases of orbital TB with a vision threatening complication. Case-1 is a 31-year-old female with a headache, a diminution of vision in the right eye, and pain in ocular movement. On examination, there was no proptosis with RAPD present in right eye and tenderness on palpation. CEMRI revealed a diffuse infiltrating lesion at the orbital apex, suggesting of inflammatory pathology. Case-2 is a 40-year-old male with similar complaints in the left eye, CECT showed edema and swelling in the optic nerve and extraocular muscle of the left eye. A detailed investigation was done, and a diagnosis of orbital tuberculosis was made in both patients. They were started on ATT and oral steroids but lost follow-up initially and due to delayed treatment, it led to irreversible vision loss. A long-term follow-up showed resolution of ocular symptoms with occasional headaches.

Randomised trial of three treatments for amblyopia: Vision therapy and patching, perceptual learning and patching alone.

Active vision therapy for amblyopia shows good results, but there is no standard vision therapy protocol. This study compared the results of three treatments, two combining patching with active therapy and one with patching alone, in a sample of children with amblyopia. Two protocols have been developed: (a) perceptual learning with a computer game designed to favour the medium-to-high spatial frequency-tuned achromatic mechanisms of parvocellular origin and (b) vision therapy with a specific protocol and 2-h patching. The third treatment group used patching only. Fifty-two amblyopic children (aged 4-12 years), were randomly assigned to three monocular treatment groups: 2-h patching (n = 18), monocular perceptual learning (n = 17) and 2-h patching plus vision therapy (n = 17). Visual outcomes were analysed after 3 months and compared with a control group (n = 36) of subjects with normal vision. Visual acuity (VA) and stereoacuity (STA) improved significantly after treatment for the three groups with the best results for patching plus vision therapy, followed by monocular perceptual learning, with patching only least effective. Change in the interocular difference in VA was significant for monocular perceptual learning, followed by patching. Differences in STA between groups were not significant. For VA and interocular differences, the final outcomes were influenced by the baseline VA and interocular difference, respectively, with greater improvements in subjects with poorer initial values. Visual acuity and STA improved with the two most active treatments, that is, vision therapy followed by perceptual learning. Patching alone showed the worst outcome. These results suggest that vision therapy should include monocular accommodative exercises, ocular motility and central fixation exercises where the fovea is more active.

Ocular Movement Examination in Peripheral Vestibular Disorders as a Tool to Improve Diagnosis: A Literature Review.

Background and Objectives: This study reviews the current literature on ocular movements, specifically focusing on nystagmus associated with peripheral vestibular disorders, to enhance diagnostic accuracy. The evaluation of ocular movements, particularly nystagmus, provides essential insights into the function and dysfunction of the vestibular system, helping clinicians distinguish between peripheral and central causes of vertigo and imbalance. Materials and Methods: A comprehensive search of PubMed was conducted using key terms such as "ocular movements", "nystagmus", "vestibular nystagmus", and "peripheral vestibular disorders". Results: The search yielded 2739 titles, and after a rigorous selection process, 52 articles were reviewed in full. Discussion: The review highlights different classifications and types of nystagmus, including physiological and pathological forms, and their diagnostic relevance in vestibular disorders such as benign paroxysmal positional vertigo (BPPV), vestibular neuritis, and Meniere's disease. Diagnostic techniques like video/electro-oculography are emphasized for their role in assessing vestibular function and identifying abnormalities. The study underscores the importance of detailed ocular examination in the diagnosis of peripheral vestibular disorders and proposes an algorithm to aid this process. Conclusions: While not a systematic review, this study highlights the importance of detailed ocular examination in diagnosing peripheral vestibular disorders and presents an algorithm to facilitate this process. It also emphasizes the need for continued research and advancements in vestibular medicine to further understand ocular movements and their clinical significance, ultimately contributing to improved patient outcomes.

Relationship between ocular motility and motor skills

Relationship between ocular motility and motor skills

Numerical Aberrations of the Extraocular Muscles and the Levator Palpebrae Superioris: An Anatomical and Clinical Insight.

To comprehensively review the literature about numerical aberrations of the orbital muscles of ocular motility (here referred to as extraocular muscles [EOMs]) and the levator palpebrae superioris (LPS). The authors summarize the embryologic bases and the possible etiopathogenetic causes of numerical aberrations of the EOMs and the LPS and organize these lesions into several broad categories. The clinical and radiologic diagnostic challenges are discussed. Numerical aberrations of the EOMs include: 1) the complete absence of EOMs, 2) duplication of an entire EOM, 3) the presence of muscle bands that connect 2 EOMs, and 4) minor morphological variations such as bifid muscles (partial splitting of the muscle). Some cases may defy categorization into any of the above or may resemble atavistic remnants of the retractor bulbi muscle. Broadly speaking, numerical aberrations of the LPS generally fall into the same categories although the LPS has several peculiar numerical anomalies of its own. Although numerical EOM and LPS variations are relatively rare and of little clinical significance, raising awareness about their presence is a fundamental clinical keystone not just for the strabismus surgeon but for the orbital surgeon as well. During orbital surgery, this may spare the surgeon from pursuing an orbital witch hunt for these benign innocuous accessory orbital structures that were accidentally discovered by the radiologist and misinterpreted as sinister etiologies. For the strabismus surgeon, the failure to identify them may result in an unfavorable surgical outcome if these structures are missed because of a lack of awareness despite being responsible for generating complex strabismus patterns or having a restrictive potential of their own.

LARGE INFERIOR RECTUS RECESSION WITHOUT LOWER LID RETRACTION: TWO INCREDIBLE TECHNIQUES

Relevance. Lower lid retraction is a frequent undesirable result following inferior rectus recession operations. Especially in relatively larger amounts of recession, a special and close relationship between lower lid retractors and muscular fascia makes the complication more severe. Purpose of the study. To introduce two methods that allow wide inferior rectus recession without causing lower eyelid retraction and to evaluate the long-term results. Material and methods. There were 25 cases and 18 control group cases in first operation technique named ‘ninety percent of posterior fibers recession of inferior rectus’ which can be perform for any vertical deviation without muscle fibrosis; and 8 cases were in second operation technique which named ‘muscle elongation with both organic tissue and non-absorbable suture’. Results and conclusion. In both technique patients’ deviation corrected and all ocular movement was free. Both operation techniques, which introduces by us, does not affected lower lid retractor and operations has both effective results and no lid problem.

12387 Late New-onset Graves' Orbitopathy: 14 Years Post-radioactive Iodine Treatment Of Graves' Disease: Case Report

Abstract Disclosure: F.F. Altaleb: None. K. Alaybaa: None. N. Aljohani: None. Introduction: Graves' orbitopathy (GO) is an autoimmune condition affecting the orbit and retro-ocular tissues, often accompanied by hyperthyroidism associated with Graves' disease, but it is rarely observed in euthyroid or hypothyroid individuals. Radioactive iodine (RAI) therapy for Graves' disease and smoking are recognized risk factors for GO development and progression. Individuals who smoke and undergo RAI treatment are significantly more likely to experience ocular lesions and worsening of GO compared to non-smokers. The exacerbation of GO post RAI therapy is attributed to elevated levels of TSH receptor antibodies, which may persist for up to a year post-treatment. Our case presents a rare occurrence of severe new-onset GO manifesting 14 years after achieving prolonged euthyroid status and successful RAI treatment for Graves' disease, accompanied by persistent TSH receptor antibody positivity that is unlikely to be suppressed by long term levothyroxine therapy. Clinical case: A 55-year-old male who’s a smoker and previously diagnosed with Grave’s hyperthyroidism, received treatment with RAI ablation therapy 14 years ago. At the time of diagnosis, there were no symptoms or signs of GO, and no history of thyroid eye disease was detected. Following the RAI treatment, he developed hypothyroidism and was promptly started on a daily dosage of 100 mcg of levothyroxine.Upon ocular examination: Visual acuity: 20/30 in both eyes. Significant restriction in extraocular muscle movements, with reported diplopia and pain. Bilateral lid retraction, proptosis, right conjunctival chemosis, and injection of the bulbar conjunctiva and caruncle, as well as lagophthalmos, were evident. No relative afferent pupillary defect observed. Color vision: 3/15 in the right eye, 15/15 in the left eye. Intraocular pressure: 22 mmHg (right eye), 16 mmHg (left eye). Optic discs unremarkable. Proptosis measurements: 26 mm (right eye), 23 mm (left eye). Ophthalmopathy clinical activity score: 7.Our laboratory analysis indicated normal thyroid function test However, the TSH receptor antibody and TPO antibody returned positive.We initiated treatment with IV methylprednisolone at a dosage of 500 Mg weekly for a duration of 4 weeks. Additionally, we introduced local measures, along with selenium supplementation. Within a week of initiating treatment, the conjunctival chemosis resolved, and there was improvement in ocular movement, resulting in mild to moderate restriction in all directions of gaze. Conclusion: This case illustrates the unexpected development of GO in a patient who had been euthyroid and effectively cured of Grave's disease for a span of 14 years following RAI treatment. The presence of TSH receptor antibodies, which are likely unresponsive to suppression by levothyroxine, as well as smoking cigarette might have contributed to the late new onset of the disease. Presentation: 6/3/2024

Ocular Motility Disorders in Pathologic Myopia

Myopia describes a refractive condition of the eye in which light rays are focused in front of the retina and is typically associated with axial elongation. The prevalence of myopia ranges from 0.8% to 75% in various population surveys. It has the highest prevalence in Asian populations. Myopia is associated with an increased risk of cataracts, glaucoma, macular degeneration, choroidal neovascularization, peripheral retinal degeneration and retinal detachment. Myopia may also be associated with abnormal ocular mobility. Strabismus associated with myopia can present in a variety of ways. In this review article, we will discuss the issues related to ocular motility disorders in pathologic myopic patients known as myopic strabismus fixus.

8158 Transient Blindness In Metformin-Associated Lactic Acidosis

Abstract Disclosure: Y. Abouelkheer: None. A. Nasir: None. M. Ibrahem: None. Transient Blindness in Metformin-associated Lactic Acidosis Background: Metformin-associated lactic acidosis (MALA) is a rare side effect of metformin use. MALA can result in acute transient blindness in patients with severe metabolic derangements. Clinical Case: A 62-year-old woman presented with severe diarrhea, poor oral intake, malaise, and vomiting on a background of metformin-treated type 2 diabetes mellitus. Laboratory investigations showed bicarbonate &amp;lt;2 mmol/L, anion gap 48 mmol/L, lactic acid 20.5 mmol/L, serum osmolality 352 mOsm/kg, negative urine toxicology screen, and positive SARS-CoV-2. In the emergency department, the patient developed sudden onset bilateral vision loss. The examination was remarkable for complete vision loss bilaterally in all fields, associated with minimally reactive pupils and spontaneous ocular movements with an otherwise unrevealing neurological examination. Computed Tomography (CT) of the brain with stroke protocol showed no evidence of acute intracranial process. CT angiogram of the brain and neck showed patent intracranial and cervical vasculature without high-grade stenosis, large vessel occlusion, or aneurysm. While receiving medical management with intravenous fluid resuscitation and sodium bicarbonate supplementation, the patient had a spontaneous return of vision with no additional neurological complications or deficits. The severe metabolic derangements were associated with distributive shock, requiring admission to the intensive care unit for urgent hemodialysis, pressor support, empiric antibiotics, and stress-dose steroids. Shortly after the patient’s only hemodialysis session, we noted the resolution of her critical metabolic disturbances, renal failure, and shock state. Laboratory investigations post-dialysis showed bicarbonate 12 mmol/L, anion gap 36 mmol/L, and lactic acid 10.5 mmol/L. Follow-up MRI showed chronic lacunar infarct of the left basal ganglia, and she was discharged home six days later. Conclusion: Transient blindness in MALA can mimic acute neurovascular events. Prompt correction of metabolic derangements can aid in reversing systemic symptoms and blindness. Reference: DeFronzo R, Fleming GA, Chen K, Bicsak TA. Metformin-associated lactic acidosis: Current perspectives on causes and risk. Metabolism. 2016;65(2):20-29. doi:10.1016/j.metabol.2015.10.014 Presentation: 6/2/2024

Inferior Rectus Muscle Thermal Injury Following Transconjunctival Blepharoplasty Using Carbon Dioxide Laser.

A 56-year-old woman was referred to the authors' hospital after the removal of the lower eyelid fat through a transconjunctival approach using a carbon dioxide laser. The patient was noted to have vertical diplopia in the primary position, with worsening diplopia on downgaze. Detachment of the right inferior rectus (IR) muscle from its insertion point was observed during exploratory surgery. The thermally damaged IR muscle fibers were attached to a location posterior to the original insertion point. At 6 months postoperatively, 8 prism diopters of right hypertropia in the primary position and a -3 degrees limitation on downgaze were still present. The patient underwent the vertical transposition of the lateral and medial rectus muscles to the IR muscle. After strabismus surgery, orthotropia was observed with no vertical diplopia in the primary gaze, but ocular motility limitation on the downgaze has permanently remained.

Local anaesthetic delivery through indwelling retrobulbar catheters for ocular pain control in horses

AbstractBackgroundEquine corneal disease is common and painful. Current pain mitigation strategies are often suboptimal, especially early in the disease.ObjectivesTo evaluate the effects of local anaesthetic delivery via indwelling retrobulbar catheter on corneal sensitivity, pupil size, pupillary light responses (PLRs), and ocular motility in normal horses.Study designRandomised, controlled crossover experiment.MethodsOne eye was randomly selected from seven horses. A 20‐gauge catheter was placed in the retrobulbar space and injected with 10 mL of 0.5% bupivacaine or 0.9% saline. Cochet–Bonnet esthesiometry (CBE), pupil photogrammetry, PLRs, and oculocephalic reflexes were evaluated before injection (t = 0) and t = 0.25, 1, 3, 6, 9 and 12 h after injection. Following a 7–14 day washout period, this procedure was repeated using the alternative injection solution. Corneal touch thresholds (CTTs) derived from CBE and pupillary areas (PA; as measured from photographs) were compared across time for each group. PLRs and oculocephalic reflexes were compared between groups at each evaluation time point.ResultsSaline did not affect CBE, PA, PLRs or oculocephalic reflexes at any time point. Bupivacaine reduced CTT compared with saline for 6 h, with maximum reduction at t = 1 h (bupivacaine: 0.08 ± 0.20 cm; saline: 4.21 ± 0.39 cm; p &lt; 0.001). Bupivacaine increased PA compared with saline for 3 h, with maximum increase at t = 3 h (bupivacaine: 349.75 ± 84.80 mm2; saline: 194.65 ± 27.03 mm2; p = 0.04). Bupivacaine injection reduced PLRs for 9 h and oculocephalic reflexes for 3 h; saline had no effect. Mild adverse effects included chemosis, blepharoedema, and transiently reduced palpebral reflex.Main limitationsReduction in CTT may not directly translate to pain control in clinical horses with corneal disease. Adverse effects of repeated injections were not evaluated.ConclusionsInjection of bupivacaine via an indwelling retrobulbar catheter in horses reduces corneal sensitivity and may be useful in reducing pain in horses with corneal disease.

Duane retraction syndrome type 1 with nonsyndromic retinitis pigmentosa – A rare atypical association

Duane Retraction Syndrome (DRS) is a rare congenital disorder of ocular motility typically characterized by a triad of variable duction limitation, globe retraction, and palpebral fissure narrowing on adduction. It is associated with various ocular and nonocular anomalies. We report a case of a 7-year-old boy with a rare association of unilateral type 1 DRS and retinitis pigmentosa. Retinal dystrophies are rarely associated with DRS, and the nature of the relationship between them remains unclear. However, this case report emphasizes the need for close monitoring and long-term follow-up of patients with DRS for retinal dystrophies.

Case report on interesting cases of congenital ocular motor apraxia

Congenital ocular motor apraxia (COMA) is an uncommon disorder of ocular motility characterized by inability to initiate voluntary horizontal saccades with associated head thrusts during horizontal fixation shifts. In addition, when ocular movements typical of COMA are observed, detailed systemic and neurologic examination should be performed to rule out any associated congenital neurologic or metabolic disorder. We report two cases of COMA, a 14-year-old male with diminution of vision, esotropia, and his face turned to the right without any systemic disease, and a 9-year-old male with esotropia, no face turn, acute lymphocytic leukemia, and isolated complete agenesis of the corpus callosum. Both cases had abnormal saccadic initiation for horizontal gaze with head thrusts to take fixation. Both cases underwent Medial rectus (MR) recession, which improved face turn and strabismus, respectively.