Corneal Anesthesia Research Articles

Comparative Study between Rocuronium And Magnesium Sulfate as Adjutants to Regional Anesthesia for Ophthalmic Surgeries using Peribulbar Block

Abstract Background Peribulbar anesthesia is frequently used in cataract surgeries. Compared to retrobulbar anesthesia, this approach is associated with less significant consequences. However, it has the disadvantages of a slower onset of orbital akinesia and the frequent requirement for block supplementation. Aim of the Work To evaluate the effect of addition of magnesium sulfate and rocuronium to standard local anesthetics mixture on the time of onset of globe and lid akinesia and corneal anesthesia for peribulbar block in ophthalmic surgeries. Patients and Methods This Prospective Double-blinded Randomized Study was carried out in the ophthalmic surgery unit, Ain Shams university hospital from January 2019 to April 2020. After institutional Ethical Board approval and obtaining written informed patients’ consents, 75 patients from both sexes, ASA physical status I-III, aged 40-80 years and having an Axial globe length less than or equals 26 mm scheduled for cataract surgery under peribulbar block were included in the study. Results Our study found statistically significant more rapid onset of action (mean time to start surgery) in rocuronium group (7.00±1.22) than control group and magnesium sulfate group (9.00±1.47 and 9.00±1.15) respectively, (p < 0.001); Moreover, no statistically significant difference was reported between control group and magnesium sulfate group. In addition, no significant difference was reported regarding duration of surgery between groups Conclusion Adding Rocuronium to local anesthetic mixture in peribulbar block during cataract surgery enhances ocular akinesia and corneal anesthesia and reduces the need for supplementary injections with no side effects and that was significantly better than Magnesium sulfate in term of rapid onset and time needed to achieve adequate condition to begin surgery. However, adding Magnesium sulfate showing good results regarding akinesia, corneal anesthesia and need for supplementary injections but it did not significantly fasten the onset of block and hence the time to start surgery.

Comparative efficacy of low-volume retrobulbar anesthesia using three commercial local anesthetics in adult horses.

To compare the efficacy of low-volume (5-mL) locoregional retrobulbar anesthesia ("retrobulbar block") by use of 3 commercial local anesthetic formulations. 8 healthy adult mares. A block-randomized, masked, controlled design was used. A single ultrasound-guided retrobulbar block was performed with 2% lidocaine, 2% mepivacaine, or 0.5% bupivacaine (n = 5 eyes/group). Contralateral eyes served as untreated controls. End points performed at baseline and time intervals up to 24 hours postblock included the following: assessment of neurophthalmic reflexes/responses, intraocular pressure, and vertical pupil diameter measurement, corneal and periocular esthesiometry, and observation for adverse effects. Low-volume block did not result in increased intraocular pressure or other adverse effects at any time point in any treatment group. Statistically significant corneal anesthesia (P < .001) was observed 1 minute after block in all groups, persisting through 4 hours after lidocaine or mepivacaine block and through 24 hours after bupivacaine block. Clinically significant periocular anesthesia was not observed in any group. Significant vertical pupil diameter increase (P < .05) was observed for up to 4 hours after lidocaine or mepivacaine block and 6 hours after bupivacaine block. Low-volume retrobulbar block with any of the 3 local anesthetic drugs evaluated was not associated with adverse effects. In terms of efficacy, mepivacaine block showed no clinical advantage over lidocaine block. However, bupivacaine block induced comparatively rapid and sustained corneal anesthesia. In comparison to published findings using a larger injection volume, low-volume retrobulbar block with lidocaine produced clinically comparable corneal anesthesia. However, periocular soft tissue anesthesia was not achieved with any local anesthetic drug at low volume.

PARALYSIE COMPLETE DU NERF OCULOMOTEUR III CAUSEE PAR UN ZONA OPHTALMIQUE A PROPOS DUN CAS

Ophthalmic herpes zoster, a manifestation of the reactivation of the varicella-zoster virus in the region of the trigeminal nerve, is primarily diagnosed based on the clinical characteristics of skin lesions and their localization. Ocular complications, including oculomotor paralysis, require early antiviral treatment to minimize ocular damage. We report the case of a 38-year-old woman presenting typical symptoms of ophthalmic herpes zoster, associated with complete oculomotor nerve III palsy and zoster encephalitis. Antiviral treatment with acyclovir led to a significant improvement. However, the patient retained corneal anesthesia resulting in the formation of a neurotrophic corneal ulcer. The risk of ocular complications associated with ophthalmic herpes zoster is real. The most serious are corneal complications and oculomotor paralysis, highlighting the crucial importance of early antiviral treatment to prevent these complications which can adversely affect the functional prognosis of the eye.

Comparative study between rocuronium and magnesium sulfate as adjuvants to local anesthetics for peribulbar block

Background &amp; Objective: Peribulbar anesthesia is frequently used in cataract surgeries. Compared to retrobulbar anesthesia, this approach is associated with less significant consequences. However, the prolonged onset of orbital akinesia and the frequent need for block replenishment are considered drawbacks. We aimed to investigate the impact of adding rocuronium and magnesium sulfate to a commonly used local anesthetic combination on the onset of corneal anesthesia and the degree of lid and globe akinesia during peribulbar block in ocular surgeries.&#x0D; Patients and Methods: This prospective double-blinded randomized study was conducted in the ophthalmic surgery operating theater, Ain Shams University Hospital from January 2019 to April 2020. We enrolled 75 patients from both sexes, with American Society of Anesthesiology (ASA) physical status I–III, ages 40-80 y, and an axial globe length less than or equal to 26 mm planned for cataract surgery under peribulbar block in the study following institutional ethical board approval and written informed patient consents. Patients were randomly divided into three groups, 25 patients per group, based on the drugs they received: Group O (control group): received local anesthetic + 0.9% normal saline (1 ml). Group M: received local anesthetic + magnesium sulphate 50 mg in normal saline. Group R: received local anesthetic + rocuronium at a dose of 0.06 mg/kg (maximum 5 mg) in normal saline.&#x0D; Results: Our study found statistically significant more rapid onset of action (mean time to start surgery) in rocuronium group (7.00 ± 1.22 min) than control group and magnesium sulfate group (9.00 ± 1.47 and 9.00 ± 1.15 min) respectively, (P &lt; 0.001); Moreover, no significant difference was noted between control group and magnesium sulfate group. In addition, no relevant difference was reported regarding duration of surgery between the groups.&#x0D; Conclusion: During cataract surgery, the addition of rocuronium to the local anesthetic mixture in the peribulbar nerve block has been found to enhance ocular akinesia and corneal anesthesia. Furthermore, the use of rocuronium demonstrated a significantly faster onset and shorter time needed to achieve the appropriate conditions to initiate the surgical procedure compared to the use of magnesium sulfate. Addition of magnesium sulfate showed good results regarding akinesia, corneal anesthesia and need for supplementary injections but it did not significantly fasten the onset of block and hence the time to start surgery.&#x0D; Key words: Cataract; Magnesium Sulfate; Peribulbar Block; Rocuronium&#x0D; Citation: Nagy M, Abo El-Ella S, El-Shafey MA, Helal AM, Zekry MR. Comparative study between rocuronium and magnesium sulfate as adjuvants to local anesthetics for peribulbar block. Anaesth. pain intensive care 2024;28(1):55−61; DOI: 10.35975/apic.v28i1.2157&#x0D; Received: February 18, 2023; Reviewed: July 30, 2023; Accepted: December 23, 2023

Analysis of the Therapeutic Efficacy of Percutaneous Balloon Double Compression for the Treatment of Recurrent Trigeminal Neuralgia

BACKGROUND: A more secure and efficacious therapy than has been developed so far is imperative for patients suffering from recurrent trigeminal neuralgia (TN). Despite numerous reports on the use of enhanced percutaneous balloon compression (PBC) techniques, such as altering compression duration and balloon pressure, none have yielded satisfactory outcomes. With these issues in mind, we have employed the PBC double-compression technique for the first time. This technique involves initially inflating a balloon to expand the adhesive tissue in Meckel’s lumen, followed by emptying of the contrast medium and subsequent slight catheter adjustment for further compression. The total duration of compression remains unchanged and may even be shortened. OBJECTIVES: The objective of this study was to assess the clinical effectiveness of the PBC double-compression technique in patients with recurrent TN and to analyze the technique’s efficacy, subsequent duration of patients’ facial numbness, and other complications. STUDY DESIGN: Retrospective study. SETTING: A single-center study. METHODS: Retrospective analysis was conducted on clinical data from 125 patients with postoperative recurrent TN who underwent double compression of the PBC and 65 patients who underwent single compression of the PBC between August 2017 and April 2022. The Barrow Neurological Institute Pain Intensity (BNI-P) score was utilized to quantify the severity of pain, while the Barrow Neurological Institute Facial Numbness (BNI-N) score was employed to separately evaluate the extent of postoperative pain relief and facial numbness. RESULTS: The BNI-P and BNI-N scores before and after PBC treatment are presented herein. At T0, there was no significant difference in the BNI-P scores between the single-compression group and the double-compression group; however, at T1-T4, the BNI-P scores of the double-compression group were lower than those of the single-compression group (P &lt; 0.05). There was no significant difference in BNI-P scores between the 2 groups at T5. At T1-T4, the BNI-N score of the double-compression group was significantly lower than that of the single-compression group (P &lt; 0.05). However, there was no significant difference in BNI-N score between the double and single compression groups at T5. In the single-compression group, one patient (1.5%) experienced insignificant pain relief on postoperative day one, while 2 patients (3.1%) suffered from pain recurrence during the 1-4-year follow-up period. Similarly, in the double-compression group, one patient (0.8%) had inadequate pain relief on postoperative day one, and 3 patients (2.4%) experienced pain recurrence during the same follow-up period. The remaining patients did not require further surgical intervention but continued to rely on regular oral analgesia. In the single-compression group, masticatory muscle weakness was observed in 50 cases (76.9%), while in the double-compression group, it was observed in 92 cases (73.6%). Perioral herpes affected 4 patients (7.1%) and 6 patients (4.8%) in the single- and double-compression groups, respectively. Facial hematoma occurred in 7 cases (10.8%) and 13 cases (10.4%) of the single- and double-compression groups, respectively; each group included one patient suffered who from diplopia. Notably, none of the patients in this study reported any instances of corneal anesthesia, anesthesia pain, aseptic meningitis, cerebrospinal fluid leakage, subarachnoid hemorrhage, carotid-cavernous fistula, or mortality. LIMITATIONS: This was a single-center retrospective study with a small sample size and relatively short follow-up time. Therefore, further evaluation of the long-term efficacy of PBC for postoperative recurrent TN is needed from multiple centers with larger sample sizes and longer follow-up periods. CONCLUSIONS: The double PBC method boasts a high cure rate, a low recurrence rate, and minimal complications, rendering the option appropriate for patients with recurrent TN and thus deserving of clinical promotion. KEY WORDS: Percutaneous balloon compression, recurrent trigeminal neuralgia, double-compression method

Comparison of central corneal thickness measured by automatic and manual analysis of optical coherence tomography.

To compare central corneal thickness (CCT) measured with optical coherence tomography (OCT) using an automatic algorithm (A-OCT) vs. manual measurements (M-OCT) with respect to the gold standard ultrasound pachymetry (USP). CCT measurements were performed on both eyes of 28 healthy subjects at four times of the day. A-OCT used an automatic software analysis of the corneal image, M-OCT was performed by two operators by setting a digital calliper on the corneal borders, and USP was performed after corneal anesthesia. Measurements were compared using a three-way repeated measures ANOVA. Bland-Altman plots were used to evaluate the agreement between OCT measurements and USP. Both A-OCT and M-OCT significantly underestimated the USP measures, with the mean difference, i.e., the systematic error, being larger for A-OCT (- 19.0µm) than for M-OCT (- 6.5µm). Good reproducibility between the two operators was observed. Bland-Altman plots showed that both OCT methods suffered from proportional errors, which were not affected by time and eye. Measuring CCT with OCT yielded lower values than USP. Therefore, clinicians should be aware that corneal thickness values may be influenced by the measurement method and that the various devices should not be used interchangeably in following up a given patient. Intriguingly, M-OCT had less systematic error than A-OCT, an important outcome that clinicians should consider when deciding to use an OCT device.

Ocular disorders among stroke patients in Federal Teaching Hospital, Lokoja, Nigeria

Objectives: To determine the pattern of ocular disorders among stroke patients in Federal Teaching Hospital, Lokoja (FTHL).&#x0D; Materials and Methods: Consecutive new stroke patients seen at the Federal Teaching Hospital, Lokoja over a 3-month period were studied. Data was collected with the use of a structured questionnaire divided into four major sections: bio-data, visual history, results of ocular assessment and NEI VFQ-25 quality of life questionnaire. Data analysis was done using SPSS for Windows, version 23.0. Univariate analyses were presented in the form of frequencies, percentages, means, ranges, and standard deviations, charts and tables.&#x0D; Results: Eighty-three patients were recruited with an age range of 40-71 years, a mean age of 55.3(±7.1) years. Thirty-nine patients (47.0%) were between the ages of 51 and 60 years. Thirty-four (41.0%) patients were females while 49(59.0%) were males. Of 46 (55.4%) patients that had neuro-imaging, stroke was ischaemic in 37(80.4%) and haemorrhagic in 9(19.6%). Of the 63 patients with left sided stroke, 2 (2.4%), 4(4.8%) and 57(68.7%) had severe, moderate and mild and normal visual impairment respectively while of the 20 patients with right sided stroke, 3(3.6%) each had severe and moderate visual impairment and 14(16.9%) had normal or mild visual impairment. Other ocular abnormalities included corneal anaesthesia and macular hole in 2(1.2%).&#x0D; Conclusion: Anterior and posterior segments, together with neuro-ophthalmic disorders were found among stroke patients in this study. Many of the ocular abnormalities are as a result of long-standing uncontrolled hypertension which caused the stroke. It is recommended that awareness should be created among the populace about uncontrolled hypertension. It is also advised that internists should refer hypertensive patients for routine ophthalmic screening.

Minimally Invasive Corneal Neurotization: 10-Year Update in Technique Including Novel Donor Transfer of the Great Auricular Nerve.

Corneal anesthesia, caused by lack of corneal innervation, is a rare but devastating condition that can lead to neurotrophic keratopathy, corneal ulceration, scarring, and blindness. Minimally invasive corneal neurotization enables transfer of regional donor sensory nerves to the cornea to provide sensation and ocular protection. The authors provide an update on technical advances and modifications that have refined the surgery over the past 10 years, as well as step-by-step intraoperative videos of corneal neurotization, noting its critical steps, pitfalls, and caveats. The videos illustrate the novel technique of using the greater auricular nerve with a sural nerve graft extension as the donor nerve for the procedure. The steps and considerations depicted will allow surgeons to carry out corneal neurotization efficiently, safely, and effectively.

Clinical outcomes of corneal neurotization using sural nerve graft in neurotrophic keratopathy.

To evaluate the efficacy of corneal neurotisation using sural nerve graft coaptation of the contralateral supratrochlear nerve in unilateral neurotrophic keratopathy and corneal anesthesia. Corneal neuralization has emerged as a potential option in the treatment of neurotropic keratopathy, however not free from the predicament. We evaluated the long-term outcome of corneal neurotisation in the treatment of unresponsive unilateral neurotropic keratopathy using surgical variations to mimic and expedient the surgical procedure. A Prospective interventional study involving patients with unilateral neurotrophic keratopathy (NK) who did not respond to medical measures was conducted. The study parameters evaluated were best-corrected visual acuity improvement, ocular surface evaluation parameters [tear break-up time (TBUT), Schirmer's 1, and ocular surface staining scores (corneal and conjunctival staining)], central corneal sensation (Cochet Bonnet esthesiometer), sub-basal nerve fiber length (SBNFL), and sub-basal nerve fiber density (SBNFD) determined by central confocal microscopy at recruitment and during follow-up at 1-month, 3-month, 6-month, 9-month and 12-month respectively, following corneal neurotization. Eleven eyes of 11 patients with unilateral neurotrophic keratopathy (NK) who underwent corneal neurotisation were studied. The mean follow-up was 10.09±2.31months (range, 6-12). Mean best corrected visual acuity in log MAR at baseline, 1.35±0.52 improved significantly to 1.06±0.76 (P = 0.012) at 3 months and continued to 0.55±0.60 (P = 0.027) at 12 months. There was a significant reduction in NK grade severity and improvement in the ocular surface as early as 1 month, and central corneal sensations (P = 0.024) as soon as 3 months. Mean corneal SBNF improved from 3.12±1.84 mm/mm2 to 4.49±1.88 at 1 month (P = 0.008), 13.31±3.61 mm/mm2 (P = 0.028) at 12 months. Mean central corneal SBNFD evident at 6 months was 1.83±2.54no/mm2 (P = 0.018) and 4.90±3.12no/mm2 (P = 0.028) at 12 months. This study substantiates the routine practice of corneal neurotisation by simplifying the intricacies observed during the procedure.

Expect the Unexpected!! – Transient Cranial Nerve Palsies after Radiofrequency Ablation of Gasserian Ganglion for Trigeminal Neuralgia

Trigeminal neuralgia is the most common type of craniofacial neuralgia, characterized by paroxysmal lancinating electric shock-like pain confined to the somatosensory distribution of the trigeminal nerve. Fluoroscopy-guided Radiofrequency Ablation of Gasserian Ganglion (RFA-GG) is the commonly performed minimally invasive pain intervention in these patients. Various complications such as masseter weakness, corneal anesthesia, dysesthesia, anesthesia dolorosa, keratitis, and cranial nerve deficits have been reported during the procedure. We present the case of a 58-year-old male diagnosed with left-sided trigeminal neuralgia involving mandibular division of trigeminal nerve (V3 division) with a Numerical Rating Scale of 9/10 at the time of presentation. As the patient was unresponsive to medical management, RFA of the V3 division of GG was performed with acceptable sensory and motor stimulation. Postablation, 1 ml of 1.0% Lidocaine injection with 2 mg injection dexamethasone was given. After the procedure, the patient complained of dizziness, left-sided hearing loss, and double vision on looking toward the left side. On examination, deviation of the angle of the mouth toward the right side, reduced blink reflex on the left side, and incomplete closure of the left eyelid were observed. Vitals were stable and there was no respiratory discomfort. The patient was reassured and monitored in the recovery room. Signs and symptoms were transient and the patient recovered completely after 45 min. Clinical findings were suggestive of the involvement of three cranial nerves: the abducens nerve, the facial nerve, and the vestibulocochlear nerve. Spillage of local anesthetic solution into adjacent cranial nerves surrounding the GG might be the causative mechanism for transient cranial nerve palsies in this case.

Neurotrophic Keratopathy After Slow Coagulation Transscleral Cyclophotocoagulation.

Decreased corneal sensation and subsequent neurotrophic keratopathy (NK) is an uncommon complication after transscleral cyclophotocoagulation (TSCPC). Post-TSCPC NK has been rarely reported in the literature, predominantly after traditional, "pop technique" continuous-wave TSCPC or micropulse CPC. The authors report the first case series of NK after slow-coagulation TSCPC (SC-TSCPC). This was a respective chart review of patients who developed NK after SC-TSCPC. The collected data included demographic data, type of glaucoma, risk factors for corneal anesthesia in addition to the number of laser spots, and the extent of the treated area. Four eyes experienced NK after SC-TSCPC. The median time for the development of NK was 4 weeks. At the final visit, 2 patients had a resolution of NK, 1 had a persistent corneal ulcer, and 1 had worsening NK and corneal perforation. NK is a rare but a vision-threatening complication that can develop after SC-TSCPC in patients with risk factors for decreased corneal sensation. Early diagnosis and proper management are crucial to reducing the risk of vision loss and improving the prognosis of these cases.

Ocular Manifestations of Lepromatous Leprosy

This study was done during the study period November 2020 to September 2022, during which 47 patients of leprosy were examined of whom 36 were Lepromatous leprosy in Ophthalmology department if Rajah Muthiah Medical College and Hospital. In our study 80.06% of Lepromatous leprosy patients had ocular manifestations, of whom maximum prevalence was present in 61-75 age group. The major ocular manifestations present were Madarosis (61.11%), Iridocyclitis (50%), Lagophthalmos (11.11%), corneal anesthesia (22.22%), corneal Hypoesthesia (16.67%), exposure keratitis (8.33%) and corneal opacity (8.33). BCVA- 3/60 to PL (U/L) – 18.06% BCVA- 3/60 to PL (B/L)- 2.8% Most of the patients of Lepromatous leprosy had Bilateral Polyneuropathy. The most common nerve affected in Lepromatous leprosy was found to be ulnar nerve and Radial cutaneous nerve. The ocular symptoms occurred more in patients of WHO grade 2 Disability than grade 2 or grade 1. Ocular symptoms occurred mostly in patients who completed Leprosy treatment. Keywords: Lepromatous leprosy, ocular manifestations, leprosy.

Ketamina frente a midazolam como adyuvante para el bloqueo peribulbar utilizando una única inyección inferonasal en los pacientes sometidos a vitrectomía: ensayo controlado aleatorizado

Introduction and objectivesThis study aimed to assess the safety and efficacy of midazolam and ketamine as adjuvants to the peribulbar block in vitreoretinal surgeries. Patients and methodsThis randomized controlled trial included 93 adult patients undergoing vitreoretinal surgeries performed with peribulbar anaesthesia. Patients were randomly allocated to 3 groups (31 participants each): control (standard anaesthetic mixture), midazolam (standard mixture+midazolam), and ketamine (standard mixture+ketamine). The primary outcomes were onset of globe akinesia and duration of analgesia. Secondary outcomes were duration of motor blockade, onset of corneal anaesthesia and lid akinesia, and changes in vital data (blood pressure, oxygen saturation, and pulse rate). ResultsThe ketamine group vs. the control and midazolam groups showed the most rapid onset of lid and globe akinesia (p<0.001) and corneal anaesthesia (0.7±0.2 vs. 1.5±0.5 and 1.2±0.4, respectively; p<0.001) and the longest duration of both analgesia (3.7±0.6 vs. 2.3±0.4 and 3.1±0.6, respectively; p<0.001) and akinesia (3.8±0.5 vs. 3.0±0.4, and 3.7±0.5, respectively; p<0.001). The midazolam group showed better outcomes than controls, but the drug was less effective than ketamine. There were no significant differences in vital data among groups (p>0.05). ConclusionsKetamine is an effective adjuvant for peribulbar blockade. It enhances both motor and sensory blockade by hastening onset and prolonging duration. These effects are desirable in lengthier ophthalmic procedures such as vitreoretinal surgeries. The effects of ketamine were superior to those of midazolam.

A rare case of congenital corneal anesthesia

A rare case of congenital corneal anesthesia

Corneal fine‐needle diathermy with intrastromal and subconjunctival injection of bevacizumab in a child with corneal neovascularization of herpetic origin

AbstractPurpose: Corneal neovascularization (CNV) in the paediatric population has a variety of etiologies including bacterial ulcers, herpes keratitis, exposure keratopathy, blepharokeratoconjunctivitis and corneal anaesthesia. Monotherapy with antiangiogenic agents or corneal fine‐needle diathermy (FND) alone do not completely resolve CNV; however, the combined treatment of these two seems to offer better results.Methods: We present the results of FND with adjuvant injection of intrastromal and subconjunctival Bevacizumab in a child with CNV of herpetic origin.Results: A 3‐year‐old patient who has been treated in our hospital for corneal involvement in the left eye (LE) due to herpetic keratitis of weeks of evolution comes to our consultation. Examination under general anaesthesia reveals in LE an inferior paracentral corneal leukoma with partial involvement of the visual axis and CNV that enters through the limbus from 5 to 8 h and begins to involve corneal stroma; no epithelial lesions, no corneal oedema or inflammatory activity in the anterior segment. After not improvement, it was decided to perform FND of lower CNV in conjunction with an intrastromal injection and another subconjunctival injection of Bevacizumab. Subsequently, it remains stable with topical and oral antiherpetic treatment, and topical corticosteroid therapy. At 3 months, the CNV reactivated, for which FND + intrastromal and subconjunctival bevacizumab was performed again. Finally, at 2 months, the patient is asymptomatic with VA LE of 1.0, with 2 corneal leukomas without CNV or epithelial lesions, and continues to be treated with oral acyclovir at prophylactic doses.Conclusions: FND of CNV together with adjuvant treatment with intrastromal and subconjunctival Bevacizumab is a good choice in children to treat those active corneal neovascularizations that do not respond to corticosteroid.

Effect of Age and Viscosity on Duration of Corneal Anesthesia with Topical 2% Lidocaine Administration.

Purpose: Formulation viscosity and patient-specific parameters such as age are important considerations in achieving patient comfort for prolonged anterior segment surgical procedures. In this study, we report pharmacodynamic and pharmacokinetic parameters of topical 2% lidocaine anesthetic decay based on formulation viscosity and subject age. Methods: Extemporaneous 2% lidocaine solution was compounded with varying percentages of carboxymethylcellulose (CMC) to adjust product viscosity. Juvenile and adult New Zealand White rabbits were utilized as a model for lidocaine-induced corneal anesthesia analysis. Following application of 20 μL in 1 eye of each animal, corneal sensitivity was measured using a Cochet-Bonnet esthesiometer at baseline and at 1-min intervals until recovery to baseline. Subsequent to washout period, the experiment was repeated for 3 replicate experiments. Results: A one-phase exponential decay model was utilized to describe rate of anesthesia decay. Bioavailability increased in a manner disproportionate to both tear film concentration and solution viscosity. In adult animals, half-life of anesthetic decay was found to range from 6.03 min with 2% lidocaine in 0.5% CMC to 9.45 min with 2% lidocaine in 1.5% CMC. In juveniles, half-life was found to be 4.46 and 3.58 min for 2% lidocaine in 1.5% CMC and commercial 2% lidocaine gel, respectively. Conclusions: Decay parameters of lidocaine-induced corneal anesthesia appear disparate from viscosity. It is postulated that viscosity-related increase in corneal contact time through reduced drainage plays a critical role in increasing bioavailability of topical anesthetics in our experimental findings, although nonlinear in character. Age is found to be an important mediator of lidocaine-induced corneal anesthesia.

Bilateral Corneal Neurotization for Ramos-Arroyo Syndrome and Developmental Neurotrophic Keratopathy: Case Report and Literature Review.

The purpose of this study was to report the use of bilateral corneal neurotization for neurotrophic keratitis in the setting of Ramos-Arroyo syndrome. The case report and surgical technique are described in detail in this article, as well as a review of the literature on corneal neurotization for congenital corneal anesthesia. We report a 17-year-old patient who underwent bilateral corneal neurotization for neurotrophic keratitis secondary to corneal anesthesia in Ramos-Arroyo syndrome. Corneal neurotization was performed with great auricular nerve transfers extended by sural nerve autografts. We present the treatment of neurotrophic keratopathy with corneal neurotization in a patient with Ramos-Arroyo syndrome. We describe how bilateral corneal neurotization using the great auricular nerve technique is a safe and effective procedure for patients with congenital/developmental corneal anesthesia.

Early Nonclinical and Clinical Development of AG-920, a Repurposed Topical Ocular Anesthetic.

Purpose: To evaluate the preclinical effects, and preclinical and clinical ocular and systemic pharmacokinetics of a new topical, non-preserved ocular anesthetic, AG-920 (articaine ophthalmic solution). Methods: Five studies: one in vitro melanin binding study; three studies in rabbits receiving an ocular dose of AG-920 evaluating corneal sensitivity, ocular tolerability, and systemic exposure to articaine and its inactive metabolite, articainic acid; and one clinical study in 14 healthy adult volunteers receiving an ocular dose of AG-920, with blood samples over 24 h. A liquid chromatography with tandem mass spectrometry (LC-MS-MS) method was used to detect both parent and metabolite with a lower limit of quantitation (LLOQ) of 0.1 and 0.2 ng/mL, respectively. Results: Melanin binding of articaine was up to 7.4%. A decrease in corneal sensitivity was noted for 20 min post-treatment in all active groups, and returned to baseline by 60 min post-dose. No dose-response relationship was observed. Concentrations of articaine in ocular matrices generally peaked early and then decreased over time. Both parent and metabolite were observed in blood at early time points. There were no ocular safety issues with AG-920. Conclusions: These early stage development studies showed that AG-920 was well tolerated in the standard preclinical models and did not cause any toxicity. AG-920 ophthalmic solution elicited a rapid onset and potentially clinically useful duration of corneal anesthesia. The studies supported the clinical evaluation of the 8% strength. Registered with clinicaltrials.gov as NCT04759339.

Prolonged Retrobulbar Local Anesthesia of the Cornea Does Not Cause Keratopathy in Mice

PurposeProlonged local anesthesia (PLA) of the cornea is currently assumed to cause neurotrophic keratitis and is strongly discouraged. We investigate whether PLA of the cornea per se causes neurotrophic keratitis.MethodsPLA of the cornea was induced in 12 female albino BALB/c mice by retrobulbar injection of a polymeric prodrug (PGS-TTX) where the site 1 sodium channel blocker tetrodotoxin (TTX) was slowly released from the polymer polyglycerol sebacate. The duration and depth of corneal anesthesia was monitored by the Cochet-Bonnet esthesiometer. Corneal injury from PLA was assessed by slit lamp examination with 2% sodium fluorescein dye, histology, corneal nerve density by immunohistochemistry with anti-β III tubulin antibody and confocal microscopy, and corneal neurotrophin levels (substance P and neurokinin A) by an enzyme-linked immunosorbent assay. PLA was also induced by topical amitriptyline (80 mM), used as a positive control for local anesthetic-induced corneal injury. Frequent ocular lubrication was provided.ResultsRetrobulbar PGS-TTX resulted in complete corneal anesthesia lasting 50.1 ± 3.6 hours and mean time to complete resolution of block of 55.1 ± 3.6 hours with no keratopathy provided lubrication was provided. Topical 80 mM amitriptyline induced complete corneal anesthesia for 24 hours and developed keratopathy. There was no difference in the histology, levels of corneal neurotrophins, and corneal nerve density between the retrobulbar PGS-TTX group and normal cornea.ConclusionsIn the absence of topical toxicity or corneal exposure, PLA of the cornea per se does not cause keratitis.Translational RelevancePLA of the cornea could be highly beneficial in acute and chronic painful corneal conditions.

Epidemiology of Corneal Neovascularization and Its Impact on Visual Acuity and Sensitivity: A 14-Year Retrospective Study.

Purpose: To quantify the severity and location of corneal neovascularization (cNV) and its impact on the visual acuity and corneal sensitivity in a cohort of the patients referred to a specialist cornea clinic and also to describe the etiology of cNV in the cohort.Methods: We retrospectively evaluated the charts of 13,493 subjects referred to the San Raffaele Cornea Unit between January 2004 and December 2018 to search for cNV diagnosis. The corneal neovascularization severity was measured in the quadrants (range: 1–4) and location was defined as superficial, deep, or both. Best spectacle corrected visual acuity (BSCVA) was measured in logMar. We used the multiple regression analysis to identify the independent predictors of logMAR, after adjusting for age, gender, keratoconus, herpes keratitis, penetrating keratoplasty, trauma, and cataract surgery.Results: Corneal neovascularization was diagnosed in 10.4% of the patients analyzed. The most prevalent etiology of cNV in our population was non-infectious corneal dystrophies/degenerations followed by herpes simplex virus infection. cNV affected OD, OS, or both eyes in 35.6, 40.2, and 24.2 of cases, respectively. Mean BSCVA (SD) was 0.59 (0.76), 0.74 (0.94), and 1.24 (1.08) in cNV one, two, and three or four of the quadrant groups. Superficial, deep, or mixed cNV occurred in 1,029, 348, and 205 eyes. Severe cNV (three or four of the quadrants) was a significant predictor of low visual acuity (p < 0.001) and reduced corneal sensitivity (p < 0.05). cNV location and its severity were associated (p < 0.05). In addition, corneal anesthesia was associated with lower BSCVA (p < 0.001).Conclusion: Severe and deep cNV are associated with the reduced visual acuity and corneal sensitivity. Our data strongly support the relevance of appropriate follow-up as cNV is a major risk factor for graft rejection.