Restoration of function following traumatic superior eyelid avulsion in a horse treated with advancement flap blepharoplasty (H-plasty) and subdermal hyaluronic acid filler

OBJECTIVE

To describe the successful restoration of superior eyelid function in a horse following traumatic avulsion using an advancement flap blepharoplasty and subdermal hyaluronic acid filler.

ANIMAL STUDIED

A 21-year-old American Paint Horse stallion who was attacked by a fellow stallion resulting in numerous traumatic injuries including avulsion of approximately 75% of the left superior eyelid.

PROCEDURES

With standing sedation and locoregional anesthesia, the superior eyelid wound was debrided and an advancement flap blepharoplasty (H-plasty) and temporary tarsorrhaphy were performed. Routine healing of the surgical site occurred over the subsequent weeks, though lagophthalmos persisted. At 2 and 4 weeks post-operatively, 2.4% cross-linked hyaluronic acid was injected subdermally into the superior eyelid to attempt to improve corneal coverage. At 8 weeks post-operatively, a complete blink was restored and the cosmetic outcome was good.

CONCLUSIONS

Injection of subdermal hyaluronic acid filler following eyelid injuries or blepharoplastic procedures that result in lagophthalmos can improve corneal coverage by the eyelids and allow for maintenance of a comfortable and visual eye.

Evaluation of Tear Production as Measured by Schirmer Test I in Dogs after Acepromazine and Acepromazine-Methadone Premedication

Simple Summary

Different sedatives and anesthetic drugs have been reported to cause adverse ocular side effects, such as an exposure keratopathy due to loss of eyelid reflex, lagophthalmos, reduced stability of the tear film and decreased basal tear production. In the present study, the effects of two sedation protocols, acepromazine (ACP) and acepromazine–methadone (ACP–MET) combination, on tear production measured by the Schirmer Tear Test (STT) 1 on canine eyes were investigated, hypothesizing that both sedation protocols cause a reduction in canine tear production for a variable time. A significant decrease in tear production until 2 h after drug administration compared to basal tear values was observed in the ACP experimental protocol, while in the ACP + MET protocol, this reduction persisted until 8 h. In the ACP + MET group, after 40 min, 100% of dogs showed STT 1 readings lower than 15 mm/min, which could predispose them to corneal injuries. The major reduction in tear production due to the ACP + MET protocol proves the need for adequate corneal hydration, particularly to discourage its use in animals with altered tear production.

Abstract

The purpose of the current study was to investigate the effects of two commonly used sedation protocols in dogs, acepromazine (ACP) and acepromazine–methadone (ACP–MET) combination, on tear production measured by the Schirmer Tear Test (STT) 1. We hypothesized that both sedation protocols cause a reduction in canine tear production for a variable time. Fifteen client-owned dogs were recruited for the study. Each dog was subjected to sedation twice, 2–3 weeks apart, and they were randomly allocated to one of two groups receiving ACP (0.015 mg kg⁻¹) or ACP–MET (0.010 mg kg⁻¹ and 0.2 mg kg⁻¹) intramuscularly. In both eyes, tear production was measured 15 min before sedation (T0) and 20 min (T20 m), 40 min (T40 m), 1 h (T1), 2 h (T2), 4 h (T4) and 8 h (T8), after drug administration. Two-way repeated measures ANOVA, followed by the Bonferroni post hoc test (p < 0.05), showed a significant effect of time (p < 0.0001) and treatment (p < 0.0001). A significant decrease in tear production at T20 m, T40 m, T1 and T2 compared to T0 was observed in the ACP experimental protocol, while in the ACP + MET protocol, this reduction persisted until T8. Comparing the two experimental protocols, no statistically significant differences were observed at T0 or T20 m, and STT 1 values were statistically lower in the ACP + MET than the ACP protocol at the other data points. In the ACP + MET group, at T40 m, 100% of dogs showed STT 1 readings lower than 15 mm/min. This finding is clinically relevant as it can predispose dogs to corneal injuries. The major reduction in tear production due to the ACP + MET protocol proves the need for adequate corneal hydration, particularly to discourage its use in animals with altered tear production. The data obtained provide important information helping clinicians to better manage the drug’s effects on tear production.

Dexmedetomidine and Tear Production: Evaluation in Dogs as Spontaneous Model for Ocular Surface Disorders

Simple Summary

The general anesthesia or sedation reduces both the tear production and the stability of tear film that protect corneal surface, predisposing itself to the exposure keratopathy. The aim of the present study was to evaluate the effects of intramuscular dexmedetomidine (DEX) on canine tear production, measured by standardized Schirmer Tear Test 1 (STT-1) strips, for the 8 h following sedation, in dogs. A significant effect of time on canine tear production was found, highlighting that dexmedetomidine sedative protocol significantly affects tear production in dogs. It is recommended to treat the canine eyes with tear substitutes to protect ocular surface health and the welfare of the dogs. The ocular lubrication should be performed during and up to 12 h after sedation. The present report could provide preliminary information to better understand the effect of DEX on the tear film dynamics.

Abstract

Tear film provides lubrication and protection to the ocular surface. The sedation reduces tear production, often leading to perioperative exposure keratopathy. The aim of the present study was to report the effects of intramuscular dexmedetomidine on canine tear production, measured by STT-1, for an experimental period of 8 h after sedation. Ten dogs who underwent sedation for routine radiologic assessment were recruited for the study. In all animals, tear production in right and left eyes was measured 15 min before sedation (T0: basal values) and 20 min (T20), 1 h (T1), 2 h (T2), 4 h (T4) and 8 h (T8) after drug administration. Analysis of variance and post hoc Bonferroni test (p < 0.05) were performed. A significant effect of time on canine tear production was found. The tear production returned to basal values at T8. So, it is recommended to treat the canine eyes with tear substitutes during and up to 12 h after sedation.

A non-surgical approach to the management of exposure keratitis due to facial palsy by using mini-scleral lenses

RATIONALE

This is a retrospective study aimed to determine the efficacy of mini-scleral contact lens in protecting the cornea and improving vision in cases of facial palsy.

PATIENT CONCERNS

Patients with facial palsy get exposure keratitis because the cornea is dry. They feel pain, discomfort and excessive watering. If left untreated, it leads to permanent damage to the cornea and loss of good functional vision. Mini-scleral lens keep the cornea covered by saline solution all wearing hours.

DIAGNOSES

Three patients (4 eyes) with acoustic neuroma, two unilateral and one bilateral, who underwent acoustic neuroma surgeries resulting in facial palsy, are presented.The gold implant and lateral tarsorrhaphy were not enough for corneal protection.Two patients (patients 1 and 2) suffered continuous pain and watering. They had to apply thick lubricant, Lacri-Lube ointment (Allergan, Inc., Dublin, Ireland), several times daily to the affected eye for 15 years. The vision of these patients in the affected eyes were counting fingers (CF) at one foot.Patient 3 with bilateral facial palsy had exposure keratitis in both eyes resulting in constant watering, pain and blurred vision.

INTERVENTIONS

The 4 eyes were fitted with mini-scleral lenses. The lenses were 15.8 mm rigid gas permeable filled with preservative free saline solution that continuously covers the cornea all wearing hours.

OUTCOMES

In patients 1 and 2 with unilateral facial palsy, vision improved through the mini-scleral lenses to 20/30 and all their symptoms disappeared.The keratitis in case 3 with bilateral facial palsy disappeared within one week of mini-scleral lens use.Follow up for 2 years showed that these patients maintained good vision with no side effects.

LESSONS

Mini-scleral lenses protected the cornea, gave comfort and improved the vision and the quality of life of these three patients with facial palsy and should be considered for all patients with facial palsy.

Nosocomial keratitis caused by methicillin-resistant Staphylococcus aureus: case report and preventative measures

A 47-year-old African-American woman was admitted to the intensive care unit of our community hospital for respiratory failure secondary to severe decompensated heart failure, requiring intubation. In the ensuing days, she developed a methicillin-resistant Staphylococcus aureus (MRSA) infection of the cornea, despite no growth of MRSA in multiple blood, sputum, and urine cultures. This unexpected corneal infection complicated her hospital stay, and increased morbidity and disease-related cost. Risk factors, warning signs, and preventative measures for MRSA keratitis secondary to lagophthalmos (inability to completely close one's eyelids) are outlined in this case report. Implementing simple precautions such as taping eyelids shut or using artificial lubrication may reduce patient morbidity and disease-related costs. These recommendations are directed to non-ophthalmic clinicians who provide care to patients in settings where MRSA colonization is widespread.

Corneal epithelial cell viability of an ex vivo porcine eye model

PURPOSE

The aim was to assess the consistency of corneal epithelial cell viability of an ex vivo porcine eye model.

METHOD

Six porcine eye models (four test and two control) were prepared for each experiment. The model has a computer-controlled mechanical arm, which could move the eyelid of the porcine eye and apply phosphate buffered saline to simulate blinking and lacrimation. The four test eyes were set up to simulate evaporative dry eyes with simulated lacrimation and blinking (one blink and one drop of buffered saline per minute) over three hours. Control A models were set up to collect pre-experimental baseline data, while those of control B were the same as the test eyes but without lacrimation and blinking simulation. All porcine eyes were kept in a closed chamber with temperature and humidity well controlled. After three hours, the cells of all eyes (except control A, which were assessed immediately before commencement of the experiment) were assessed. The eyes were first dipped into 0.4 per cent trypan blue solution. Following the dissection and separation of the cells, the number of dead cells were then counted under the microscope with a field size of 0.25 mm(2). The experiment was repeated 11 times.

RESULTS

No significant differences were found in the number of dead cells among the four test eyes in both the central and peripheral cornea. There were significantly more dead cells in the test eyes compared to control A but significantly less when compared to control B. More dead cells were found in the central cornea than the peripheral cornea in the test eyes but the difference was not observed in controls A and B.

CONCLUSION

Epithelial cell viabilities among the four porcine eye models with simulated lacrimation and blinking were consistent. The majority of cells were viable before the experiment and simulated lacrimation and blinking maintained more viable cells over time.