Bandage contact lens retention in dogs-A pilot study.

OBJECTIVE: To assess and compare retention, application characteristics, and patient tolerance of nine bandage contact lens types from four manufacturers. ANIMALS STUDIED: Six research Beagles were used in this pilot study. PROCEDURE: Five bandage contact lens types from two veterinary brands and four bandage contact lens types from two human brands were evaluated in six research Beagles. Placement ease, the dogs' contact lens tolerance, and contact lens retention time for up to 14 days were recorded. Statistical analysis with a linear mixed model was performed. RESULTS: Veterinary contact lenses had an average retention time of 0.4 days (range 0-7 days, with an average of 10% and 3% retained ≥1 and ≥7 days, respectively), while human contact lenses had a significantly (P < 0.0001) longer average retention time of 5.2 days (range 0-14 days, with an average of 83% and 37.5% retained ≥1 and ≥7 days, respectively). Specifically, Johnson and Johnson Vision Care Acuvue® Oasys™ with Hydraclear™ Plus lenses were retained significantly longer than all veterinary lenses, and Bausch and Lomb PureVision® 2 lenses were retained significantly longer than Keragenix HydroBlues™ 18 and AnimaLens™ HRT 78 18 mm lenses. CONCLUSION: Although all bandage contact lenses were easy to use and well tolerated by the dogs, the human lenses were retained significantly better and longer than the veterinary lenses. Additionally, human lenses were retained significantly better and longer than veterinary lenses of similar measurements. This suggests factors other than measurement and associated fit may determine contact lens retention time.

Effect of bandage contact lens wear and postoperative medical therapies on corneal healing rate after diamond burr debridement in dogs.

PURPOSE: To determine the effect of bandage contact lens wear and type of post-operative medical treatment on corneal healing rates in dogs after diamond burr debridement. ANIMALS STUDIED: 237 client-owned dogs. PROCEDURES: Canine patients having undergone diamond burr debridement (DBD) for treatment of spontaneous chronic corneal epithelial defects (SCCEDs) were included. Patients were put into 1 of 12 different groups based on type of postoperative medical regimen and whether a bandage contact lens (BCL) was utilized. Each dog was examined on a routine basis until the cornea was fluorescein negative. Data points collected included age, sex, breed, diabetic status, eye affected, Schirmer tear test 1, rebound tonometry, type and frequency of topical antibiotic, use of topical sodium chloride, use and retention of BCL, and days until healed. RESULTS: A total of 237 dogs, each contributing one eye to the study, underwent DBD for SCCEDs. All eyes treated had estimated median ± standard error (SE) days to heal of 9.37 ± 0.42 days. When sodium chloride and BCL were utilized, ofloxacin had a significantly shorter median healing time when compared to oxytetracycline (adjusted P = 0.0158) and tobramycin (adjusted P = 0.0261). BCL use significantly improved healing times (P = 0.0002). Overall BCL retention rate was 62.02% (80 of 129). PureVision lenses were retained more often compared to Acrivet lenses (P < 0.0001). Overall, BCL retention significantly improved healing rates (P = <0.0001). CONCLUSIONS: Postdebridement antibiotic type or use of sodium chloride ointment had minor effects on healing rates. Bandage contact lens use and retention significantly improves healing times.

Dark adaptation time in canine electroretinography using a contact lens electrode with a built-in light source.

The purpose of this study was to evaluate the dark adaptation time in canine electroretinography (ERG) using a contact lens electrode with a built-in LED. Twelve eyes of six normal laboratory beagle dogs were used and exposed to steady room light at 500 lux for 30 min for light adaption. ERG was recorded at different time points during dark adaptation in sedated and light-adapted beagles. The stimulus intensity was 0.0096 cd/m(2)/sec. The b-wave amplitude increased significantly until 25 min of dark adaptation, whereas no significant changes in amplitudes were observed after 30 min. Dark adaptation for more than 25 min would be necessary for accurate ERG in canine ERG using a contact lens electrode with a built-in LED.

Use of bandage contact lenses for treatment of spontaneous chronic corneal epithelial defects in dogs.

OBJECTIVE: To determine whether polyxylon bandage contact lenses influence healing time and ocular comfort in the management of spontaneous chronic corneal epithelial defects in dogs. METHODS: Twenty dogs with spontaneous chronic corneal epithelial defects were included. All dogs were treated by debridement under topical anaesthesia at the first presentation. Ten dogs were assigned to the study group (application of a polyxylon bandage contact lens), and the remaining ten served as a control group. The healing time and ocular (dis)comfort were evaluated by assessment of the clinical findings and an owner-based questionnaire. All dogs received the same topical and systemic medication. RESULTS: Healing time for dogs in the study population was significantly shorter (mean 14±0 days) than for dogs in the control group (mean 36±17 days; P=0·005). The spontaneous chronic corneal epithelial defects had completely healed at the first recheck in all dogs with a polyxylon bandage contact lens. The duration of blepharospasm following debridement was significantly shorter in the study population (mean 4±4 days) than in the control group (mean 30±20 days; P=0·001). CLINICAL SIGNIFICANCE: The use of polyxylon bandage contact lenses is beneficial in the management of spontaneous chronic corneal epithelial defects.

Effect of corneal contact lens wear on healing time and comfort post LGK for treatment of SCCEDs in boxers.

PURPOSE: To determine whether dogs with spontaneous chronic corneal epithelial defects (SCCEDs) would heal faster and with an improved comfort score following linear grid keratotomy (LGK) combined with corneal contact lens (Acrivet(™) ) wear when compared to dogs having the LGK procedure alone. STUDY DESIGN: Prospective study. METHODS: Twenty-seven boxer dogs (27 eyes) diagnosed with a SCCEDs were enrolled in the study. A LGK was performed on all dogs under dexmedetomidine and butorphanol sedation. Fourteen eyes were randomly assigned to receive a corneal contact lens. The dogs were evaluated typically at 7, 10, and 14 days or until the ulceration was healed. Client surveys were completed by the owners to subjectively assess comfort level and contact lens retention. Statistical analyses were performed utilizing generalized linear models and survival analysis with the Wilcoxon-Gehan test to evaluate group differences. RESULTS: All ulcers healed after the LGK procedure. Dogs with bandage contact lenses had a statistically significant (P = 0.035) decrease in median healing time (7 days (95% CI [7,9]) compared to those without contact lenses (10 days (95% CI [7,12])). There was no difference in subjective comfort score between treatment groups. Early contact loss occurred in 28.6% (95% CI [8.4%, 58.1%]) of dogs. All of the Acrivet(™) ruler corneal measurements agreed to within 1 mm (95% CI [87.2%, 100%]) of the Jameson caliper measurements of horizontal corneal diameter. CONCLUSIONS: The use of corneal bandage contact lenses significantly decreased median healing time although there was no effect on subjective comfort score. The Acrivet(™) ruler measurements were accurate in determining corneal diameter and therefore contact lens size.

Management of spontaneous chronic corneal epithelial defects (SCCEDs) in dogs with diamond burr debridement and placement of a bandage contact lens.

Objective To describe the outcome of canine spontaneous chronic corneal epithelial defects (SCCED) treated with diamond burr debridement (DBD) and bandage contact lens placement (BCL). Animal studied Forty eyes of 36 dogs presenting to a single private practice. Procedures A retrospective review of medical records was performed. Cases were eligible for inclusion if they were newly diagnosed with SCCED by a veterinary ophthalmologist and treated with DBD/BCL. All patients received a complete ocular examination followed by DBD using a battery-powered, handheld motorized burr (Algerbrush(®) , Alger Equipment Company, Lago Vista, TX, USA). A BCL was placed post-debridement in all patients. Data were analyzed for sex, age, breed, duration of clinical signs prior to DBD; number of debridements required before healing was achieved; contact lens retention, complications attributed to DBD, and additional surgical interventions were required to achieve healing. Results The median time to first recheck examination was 7 days (IQR 7-9 days) with 28/40 (70%) of cases healed at this examination. The mean time to second recheck examination was 15.5 ± 5.5 days with 37/40 (92.5%) healed by this examination. The median time to final recheck examination was 19 days (IQR 18-35.5 days) with a range of 18-52 days. All cases resolved by the third and final recheck examination. A second DBD/BCL was performed in 5/40 (12.5%) of cases. The BCL retention rate was 95% over all examination time points. No case required a keratectomy or other surgical intervention to achieve healing. The only complication observed was one case of suspected bacterial keratitis post-DBD/BCL. Conclusions Results suggest that DBD/BCL is safe and effective for treatment of canine SCCED.

Accuracy of intraocular pressure measurements in dogs using two different tonometers and plano therapeutic soft contact lenses.

OBJECTIVE: To compare and evaluate the accuracy of intraocular pressure (IOP) measured through a therapeutic contact lens, using applanation (TonoPen XL(®)) and rebound (TonoVet(®)) tonometers in enucleated dog eyes. ANIMALS STUDIED: A total of 30 enucleated eyes from 15 beagle dogs. PROCEDURES: To measure accurate IOP, the anterior chamber of each enucleated eye was cannulated with two 26-gauge needles and two polyethylene tubes were connected vertically to an adjustable reservoir bag of normal saline and a pressure transducer. IOP was measured by the TonoPen XL(®) followed by the TonoVet(®) without a contact lens. After a contact lens was applied to the cornea, IOP was re-measured in the same order. Three consecutive IOP measurements were performed using both tonometers. RESULTS: Without the contact lens, the IOP values obtained by both tonometers correlated well according to the regression analysis (TonoVet(®): γ(2) = 0.98, TonoPen XL(®): γ(2) = 0.97, P < 0.001). The TonoPen XL(®) consistently underestimated values as transducer IOP increased; however, IOP values measured with the TonoPen XL(®) were in close agreement and were less variable than those determined with the TonoVet(®) when a contact lens was applied to the cornea. Bland-Altman analysis was used to determine the lower and upper limits of agreement (TonoVet(®): -29.7 and +21.1 mmHg, TonoPen XL(®): -3.9 and +3.6 mmHg) between the two devices. CONCLUSIONS: This study suggests that the TonoPen XL(®) is a useful tonometer for dogs wearing therapeutic contact lenses, and importantly, contact lenses would not need to be removed prior to IOP measurement.

Functional disorder of the retina in manganese-deficient Japanese quail revealed by electroretinography using a contact lens electrode with built-in light source.

Manganese deficiency results in neurological and skeletal defects, together with ultrastructural disarrangement of the retina in rats. Wild birds show a range of Mn concentrations in their tissues, including the liver, raising the possibility of Mn-related disorders in the wild. Electroretinography (ERG) provides a useful noninvasive approach to evaluate visual function. This method is especially useful in birds, as objective analysis of them is very difficult, while they have well-developed vision. In this study, we carried out a convenient and reliable ERG recording using a contact lens electrode with a built-in light source (LED electrode) of Japanese quail (Coturnix coturnix japonica) fed a Mn-deficient diet. After 10 min light adaptation, single-flash and flicker cone responses were reproducibly recorded to cause an intensity-dependent increase in amplitude of both a-wave and b-wave in single-flash ERG. Mn-deficient feeding markedly decreased the Mn concentration in the liver by almost half in 3 to 6 weeks, followed by body weight loss in 13 to 15 weeks. Implicit time of a-wave and b-wave cone response by single-flash stimulation was significantly delayed in quail with a Mn depletion from 3 to 6 weeks. Every cone response of the Mn-deprived quail had a tendency to decrease amplitude. The ultrastructure of cone photoreceptor cells was disorganized by Mn deficiency, including changes in outer segment discs of photoreceptor cells. These results suggest the essential role of Mn in the integrity of the retinal function of birds.

Electroretinography using contact lens electrode with built-in light source in dogs.

Electroretinography (ERG) is an effective method for the diagnosis of retinal disease. In the dog, dependable ERG recording is difficult without the use of an expensive device like a Ganzfeld full-field stimulator. The International Society for Clinical Electrophysiology of Vision has defined the standard flash stimulus condition (SF) and evaluation of the retina using the b/a ratio in humans. In dogs, evaluation using the b/a ratio has not been reported, whereas the intensity of SF has been defined. In this study, we performed a convenient ERG recording method using a contact lens electrode with a built-in light source (LED-electrode), and confirmed SF as reported previously. ERG recordings were performed on 15 healthy beagle dogs under sedation. We performed bilateral ERG at 12 different intensities after 30 min dark adaptation. After 10 min light adaptation, we recorded single flash cone and flicker cone response using the SF determined in this study. In this study, SF of 3.0 cd/m(2)/sec (6,000 cd/m(2), 0.5 msec) resulted in b/a=2. The intensity for rod response that recorded only the b-wave was 0.0096 cd/m(2)/sec (80 cd/m(2), 0.12 msec). We could achieve ERG for each response easily and smoothly under sedation, and without general anesthesia. Using an LED-electrode, we could perform more quantitative and reproducible ERG examinations than with traditional methods. We propose that the b/a ratio is the most useful parameter in ERG reporting for evaluating retinal function.

Cosmetic globe surgery in the horse.

Effects of traumatic injury or inflammation on the equine eye can be catastrophic. These ocular conditions can frequently result in blindness or chronic pain. In addition to blindness and pain, permanent unsightly cosmetic defects can occur. This article addresses options available for improved cosmetic outcome in horses with ocular scars or requiring enucleation. Many of these options have been described in detail previously. New information has been added to the discussion of each option where pertinent.

Aphakic hydrogel contact lens fitting on a monocular canine: a case report.

BACKGROUND: Though plano bandage contact lenses used for therapeutic purposes are not uncommon for dogs, no literature regarding contact lenses to correct aphakic canines currently exists. CASE REPORT: Oliver, a 7-year-old terrier mix, was aphakic in his left eye and essentially blind in his right eye as the result of a large retinal detachment. Surgical complications and endothelium damage contraindicated an intraocular lens implant in his left eye. While co-managed with his veterinary ophthalmologist, Oliver was prescribed an aphakic hydrogel contact lens to improve his monocular vision. CONCLUSION: Oliver was successful (by clinical criteria) with his contact lens. Although it is difficult to quantify his vision without a visual evoked potential, Oliver appeared more attentive and confident with the contact lens. This case report demonstrates a successful canine aphakic contact lens fit through the efforts of his owners, co-managing veterinary ophthalmologist, and optometrist.

Headshaking in horses: possible aetiopathogenesis suggested by the results of diagnostic tests and several treatment regimes used in 20 cases.

Twenty mature horses with typical headshaking of 2 week-7 year duration were studied. Clinical examinations included radiography of the head and nasopharyngeal endoscopy. All were assessed at rest and at exercise, both before and after fitting an occlusive nasal mask, application of tinted contact lenses and the perineural anaesthesia of the infraorbital and posterior ethmoidal branches of the trigeminal nerve. Infraorbital anaesthesia had no effect in 6/7 cases but 11/17 (65%) cases showed a 90-100% improvement following posterior ethmoidal nerve anaesthesia. Tinted contact lenses had no apparent long-term benefit, although 2 cases showed a transient improvement. We found no other evidence to suggest a photic aetiology in the current series of cases. Treatment regimens based on the results of the diagnostic investigative methods included sclerosis of the posterior ethmoidal branch of the trigeminal nerve. This was effective in some cases but the benefits were temporary. Cyproheptadine alone was ineffective but the addition of carbamazepine resulted in 80-100% improvement in 80% of cases. Carbemazepine alone was effective in 88% of cases but results were unpredictable at predefined dose rates. The positive response to carbamazepine, combined with the clinical features is consistent with involvement of the trigeminal nerve, particularly the more proximal branches such as the posterior ethmoidal nerve. Headshaking has some clinical features in common with trigeminal neuralgia in humans. As a result of the findings detailed in this paper, we conclude that a trigeminal neuritis or neuralgia may be the basis of the underlying aetiopathology of equine headshaking. Initial observations of the positive response of headshakers to carbamazepine therapy is encouraging. However, future studies will include a more detailed investigation of dosages, duration of effectiveness (in some cases it appears short-lived) and other effects. In practice there is a realistic possibility of controlling but not curing headshaking with carbamazepine therapy at the present time. Other future investigations will include details of the functional anatomy of the trigeminal nerve and the role of the P2 myelin protein in headshaking and other neurological disease.

Ocular cosmetic and prosthetic devices.

Specific details on surgical procedures, although not covered here, are available in other references. Factors enhancing the overall cosmetic appearance obtained with procedures are emphasized, providing information that should allow veterinarians to offer clients a good cosmetic appearance and effective treatment for disfiguring ocular problems in their horses. Questions regarding procedures should be addressed to your referral ophthalmologist or, in the case of a corneoscleral prosthesis, the ocularist assisting.

Management of a persistent corneal erosion in a boxer dog.

A dog was presented to the New York State College of Veterinary Medicine with a one-month history of corneal ulceration. The corneal lesion was diagnosed as a persistent corneal erosion (PCE) and treated initially with debridement and supported with a contact lens. One week later, the corneal erosion remained unepithelialized. Following debridement, multiple anterior stromal punctures were performed. Within 10 days, the erosion was healed as evidenced by coverage of the cornea with adherent, uninterrupted epithelium. The proposed etiology and management of PCE in dogs is discussed.

Tinted contact lenses for treatment of retinal degeneration in a Greyhound.

The owner of a Greyhound reported photophobia and disturbance of vision in the dog's left eye. Racing performance, previously excellent, had become erratic under bright lighting. An irregular area of retinal degeneration was observed in the left eye. We used a flush-fitting scleral (haptic) lens made of tinted lucite with visible transmission of 9% to enhance rod function. Behavioral indications and racing performance improved after the fitting of this lens. The report describes a method of contact lens manufacturing, which will help veterinarians solve vision-related problems in domestic animals.

Scleral contact lens electrodes for electroretinography in domesticated animals.

Contact lens electrodes are necessary to produce a high quality electroretinogram. Comparison of the electroretinogram recorded with the contact lens electrode and a needle electrode showed a great difference. Contact lens electrodes showed a 50 percent or greater amplitude and less artifacts. This report details the procedure for construction of the contact lens electrodes for domestic animals.