Vision outcome with antiglaucoma therapy and prognostic factors in canine glaucoma: A 6-years retrospective study in Title Japan Author(s) Kubo, Akira; Ito, Yosuke; Masuko, Arisa; Maehara, Seiya; Miyasho, Taku; Nakade, Tetsuya Citation Japanese Journal of Veterinary Research, 67(1), 93-102 Issue Date 2019-02 DOI 10.14943/jjvr.67.1.93 Doc URL http://hdl.handle.net/2115/72747 Type bulletin (article) File Information p093-102 Akira Kubo.pdf Instructions for use Hokkaido University Collection of Scholarly and Academic Papers : HUSCAP Japanese Journal of Veterinary Research 67(1): 93-102, 2019 REGULAR PAPER Clinical Case Report Vision outcome with antiglaucoma therapy and prognostic factors in canine glaucoma: A 6-years retrospective study in Japan Akira Kubo1, 2,＊), Yosuke Ito1), Arisa Masuko2), Seiya Maehara2), Taku Miyasho3) and Tetsuya Nakade2) 1) Veterinary Eye Care Service, 1-1-8 Kita 13-jo-nishi, Kita-ku, Sapporo-shi, Hokkaido 001-0013, Japan 2) Small Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University, 582 Bunkyodai-Midorimachi, Ebetsu, Hokkaido 069-8501, Japan 3) Laboratory of Animal Biological Responses, Department of Veterinary Science, School of Veterinary Medicine, Rakuno Gakuen University, 582 Bunkyodai-Midorimachi, Ebetsu, Hokkaido 069-8501, Japan Received for publication, June 6, 2018; accepted, September 17, 2018 Abstract Vision outcome provides invaluable information in clinical decision making in the management of canine glaucoma. In the present study, data of glaucoma dogs were retrospectively evaluated for vision outcome by treatment modality (with or without surgical implantation of the Ahmed glaucoma valve, AGV) and by type of glaucoma, sex and breed in cases of medically treated glaucoma. Among 1990 dogs presented with eye diseases between 2011 and 2017, 224 dogs (11.3%) were diagnosed with glaucoma at initial presentation and 228 eyes of 207 dogs have follow-up records of at least 30 days were included in the analysis. At the time of first presentation, 62/228 eyes (27.2%) were visual. Visual preservation rates were constantly significantly higher in dogs that received AGV placement with a median time to vision loss of 76.4 weeks vs. 9.6 weeks in dogs that received medical treatment alone. Among dogs treated medically, vision outcome was comparable between two types of glaucoma (i.e., primary and secondary) and between sexes. Medically treated Shiba dogs showed significantly lower vision preservation rates and a shorter median time to vision loss compared to other breeds. These results suggest that AGV implants result in better vision outcome compared to medical therapy alone and should be considered in dogs that are visual at the time of presentation and suitable for surgery. And Shiba dogs are considered as the factor that indicate poor vision outcome of medical treatment alone in the present study. Key Words: Antiglaucoma therapy, canine glaucoma, prognostic factors, vision outcome Introduction intraocular pressure (IOP) resulting in disrupted axoplasmic flow in the optic nerve and The canine glaucomas are a group of ocular degeneration or death of retinal ganglion cells diseases characterized by increased levels of and their axons that are detrimental to the *Corresponding author: Akira Kubo, Veterinary Eye Care Service, 1-1-8 Kita 13-jo-nishi, Kita-ku, Sapporo-shi, Hokkaido 001-0013, Japan Phone: +81-11-792-1722. E-mail: [email protected] doi: 10.14943/jjvr.67.1.93 94 VISION OUTCOME FACTORS CANINE GLAUCOMA JAPAN maintenance of vision and health of the eye. Materials and Methods Glaucomas can be classified into two types based on the possible etiology: primary, if the increase Subjects: Among 1990 dogs presented to a in IOP develops without concurrent diseases and referral ophthalmology practice (Veterinary Eye is hereditary or breed-related; and secondary, if Care Service) during the six years from October IOP elevation is associated with other ocular or 2011 to October 2017, 224 dogs (11.3%) were systemic disease15,16). diagnosed with glaucoma at initial presentation Glaucomas are incurable, and continued and 207 dogs (228 eyes) for which records of at treatment is needed to maintain vision and least 30 days of follow-up evaluation were control IOP. Especially in dogs, glaucomas may available were included in the study (Fig. 1). All still progress to the end stage despite various dogs had received a routine eye examination antiglaucoma therapies and result in uncontrolled including the menace response, dazzle reflex, IOP and vision loss. Thus, the main and IOP, slit lamp biomicroscopy and fundus important goal of canine glaucoma therapy is to examination. maintain suitable IOP and vision as long as possible. Current antiglaucoma treatment is Glaucoma classification and signalment: Subjects primarily based on medical therapy using topical were classified based on the cause of glaucoma: and oral antiglaucoma drugs. Recently, however, 1) primary glaucoma; 2) secondary glaucoma and new surgical devices and systems have been 3) glaucoma of unknown etiology, and the developed and provided longer IOP control and number of cases (eyes), age, sex and breed were vision maintenance than previous surgical analyzed. Breeds were reported only if there techniques. Commonly employed techniques among were at least 6 dogs, and breeds fewer than 6 veterinary ophthalmologists include anterior dogs were reported as “others/other breeds.” chamber shunts (e.g., Ahmed glaucoma valve, AGV, and ExPress device implantation) and Vision at initial presentation: Vision at the first endoscopic ciliary body photocoagulation. The presentation was analyzed by type of glaucoma, success rate and outcome of each technique have sex and breed. Eyes were considered visual when been reported previously2,17,21). However, these the menace response and/or dazzle reflex were reports mainly focus on the results of each present, nonvisual when both were absent, and surgical technique or combined techniques and inconclusive (one of menace response or dazzle do not provide a full perspective that every reflex was absent and another was inconclusive, practitioner needs when deciding the best or both were inconclusive). The dazzle reflex was treatment options. The purpose of the present examined by a handheld slit lamp (SL-15, Kowa study was to determine the prognostic factors of Company, Aichi, Japan) with the maximum light vision retention by retrospectively evaluating the output. outcomes of canine antiglaucoma therapies at a referral ophthalmology center. Factors evaluated Comparison of vision outcome: Vision outcomes included treatment modality (AGV implants or were compared between medical treatment alone medical treatment alone) as well as type of and AGV implants in glaucoma dogs that were glaucoma, sex and breed in cases that were visual at the time of initial presentation. Dogs treated only medically. that received medical therapy alone were further divided by etiology (primary or secondary), sex and breed for a comparison of vision outcome. The medical therapy regimen included topical β-blockers (0.25% nipradilol, 0.5% timolol maleate Akira Kubo et al. 95 Fig. 1. Flowchart of the subjects, the classification for comparison of vision outcome. Among 1990 dogs presented during the six years, 224 dogs (11.3%) were diagnosed with glaucoma at initial presentation and 207 dogs (228 eyes) for which records of at least 30 days of follow-up evaluation were available were included in the study. Vision outcomes were compared between AGV implants and medical treatment alone in glaucoma dogs that were visual at the time of initial presentation (①). Dogs that received medical therapy alone were further divided by etiology (②), sex (③) and breed (④) for a comparison of vision outcome. and 2% carteolol hydrochloride), carbonic anhydrase firocoxib and robenacoxib) and systemic diuretics inhibitors (1-2% dorzolamide hydrochloride and (50% oral glycerin and intravenous mannitol). All 1% brinzolamide), prostaglandin analogues AGV procedures were performed by the same (0.005% latanoprost, 0.0015% tafluprost and surgeon using a VFP8 valve (CARA Life, Rancho 0.03% bimatoprost), large conductance calcium- Cucamonga, CA, U.S.A.) and the standard activated potassium channel activators (0.12% technique4). isopropyl unoprostone), corticosteroids (0.05% difluprednate, 0.1% prednisolone acetate, 0.1% Statistical analysis: The analyses were conducted dexamethasone, 0.1% methylprednisolone), non- using BellCurve for Excel (Social Survey Research steroidal anti-inflammatory drugs (NSAIDs) Information Co., Ltd., Tokyo, Japan). The mean (0.1% diclofenac and 0.1% pranoprofen) as well age was compared by Student’s t-test, while as oral prednisolone (1-2 mg/kg/day), intravenous contingency tables were used to analyze sex methylprednisolone sodium succinate (10-15 mg/ and breed about glaucoma classification. A kg), oral or subcutaneous NSAIDs (carprofen, Chi-squared test was used for comparison among 96 VISION OUTCOME FACTORS CANINE GLAUCOMA JAPAN Fig. 2. Types of glaucoma and breed. The overall incidence was highest in Shih Tzu (18.9%) followed by Shiba (17.5%) and Miniature Dachshund (MD) (12.3%). Shiba had a higher incidence of primary glaucoma than secondary glaucoma. Among breeds shown, MD was least likely to develop primary glaucoma, while Toy Poodle (TP) was more likely to have glaucomas of unknown etiology. ACS: American Cocker Spaniel. Single asterisk (*) indicates significant overrepresentation, and double asterisks (**) indicate