Retinoschisis: a retrospective study of an uncommon retinal change in cats and dogs.

Retinoschisis is a poorly documented form of retinal degeneration characterized by cyst-like splitting that occurs between the inner nuclear and outer plexiform layers. The pathogenesis of retinoschisis is incompletely understood, but congenital, acquired and secondary aetiologies (glaucoma, inflammation, neoplasia) are described in humans. This retrospective study investigated the prevalence and associated histological and clinical features of retinoschisis in cats and dogs submitted for biopsy over a 10-year period. Of 140 samples with documented 'retinal vacuolation', four out of 120 (3%) canine samples and one out of 20 (5%) feline samples had changes consistent with retinoschisis. In most cases (80%), there was concurrent retinal detachment. In cases with available histories, increased intraocular pressure, proptosis and retinal detachment were reported clinical findings. In cats and dogs, retinoschisis is a retinal change that is generally secondary to other ocular lesions.

Outcome of 25-gauge pars plana vitrectomy via a lateral approach without proptosis of the globe: A retrospective study in 72 dogs (78 eyes).

OBJECTIVE: To evaluate the postoperative visual outcome and complications of 25-gauge pars plana vitrectomy (PPV) via a lateral approach without proptosis of the globe in dogs. PROCEDURES: We reviewed the medical records of dogs diagnosed with giant rhegmatogenous retinal detachment (RRD) at Yokohama Animal Eye Clinic from 2016 to 2019 and treated by 25-gauge PPV. Medical records included signalment, follow-up time, etiology and duration of RRD, angle between the outermost trocar ports, immediate postoperative anatomic success rate, pre- and postoperative visual status, and postoperative complications. RESULTS: Seventy-two dogs (78 eyes, 13 breeds) were included. The most common breed was the Toy Poodle (48.6%), and the mean follow-up time was 690.6 days. The most common etiology of RRD was cataract surgery (46.2%). The mean angle between the outermost trocar ports was 71.4º. Immediate postoperative anatomic success was noted in all eyes. Vision was regained or maintained in 87.2% of eyes, and the mean time to return of vision was 28.5 days. Maintenance of vision until the last known follow-up was noted in 73.5% of eyes. The most common postoperative complication was glaucoma (40.3%), and glaucoma was the most common etiology of postoperative vision loss (88.9%). CONCLUSION: Twenty-five gauge PPV via a lateral approach without proptosis of the globe is a successful method for treating canine giant RRD.

Silicone allergy associated with intraocular silicone ball prosthesis in a dog.

A 13-year-old, male Pomeranian dog was presented for scleral rupture with intraocular hemorrhage and retinal detachment in the right eye. After intrascleral silicone ball prosthesis, recurrent swelling and granulomatous blepharitis were observed for 140 d and finally melting keratitis developed. Although an intraorbital prosthesis was implanted, recurrent, serious, erosive, and ulcerative blepharitis developed with high plasma C-reactive protein concentrations. Since the blepharitis could not be controlled, the silicone ball was removed and the affected orbit was debrided. The blepharitis resolved rapidly, and the orbit healed routinely. Positive allergic reactions to silicone were discovered through a patch test. Key clinical message: To the authors' knowledge, this is the first report on silicone allergy in a dog with positive allergic reactions to silicone in the patch test.

Allergie au silicone associée à une prothèse intraoculaire en boule de silicone chez un chien. Un chien poméranien mâle de 13 ans a été présenté pour rupture sclérale avec hémorragie intraoculaire et décollement de la rétine de l'oeil droit. Après l'implantation intrasclérale d'une boule de silicone comme prothèse, un gonflement récurrent et une blépharite granulomateuse ont été observés pendant 140 jours et une kératite fondante s'est finalement développée. Bien qu'une prothèse intra-orbitaire ait été implantée, une blépharite récurrente, grave, érosive et ulcéreuse s'est développée, avec des concentrations plasmatiques élevées de protéine C réactive. Comme la blépharite ne pouvait pas être contrôlée, la boule de silicone a été retirée et l'orbite affectée a été débridée. La blépharite s'est résolue rapidement et l'orbite a guéri normalement. Des réactions allergiques positives au silicone ont été découvertes grâce à un test cutané.Message clinique clé :À la connaissance des auteurs, il s'agit du premier rapport sur une allergie au silicone chez un chien ayant des réactions allergiques positives au silicone lors du test cutané.(Traduit par Dr Serge Messier).

Intraoperative findings and postoperative results associated with cataract surgery performed after retinal reattachment surgery in dogs-36 cases (41 eyes).

OBJECTIVE: To report intraoperative findings and complications associated with cataract surgery performed after retinal reattachment surgery (RR) via pars plana vitrectomy (PPV) using perfluoro-n-octane (PFO), laser retinopexy, and silicone oil tamponade in dogs. ANIMALS STUDIED: Retrospective record review of dogs that underwent post-RR cataract surgery. Signalment, time between RR and cataract surgery, type of lens extraction, postoperative visual status, and intra- and postoperative complications were recorded. Cataract formation or progression after RR was categorized as early (≤12 months) or late (>12 months). RESULTS: A total of 36 dogs (41 eyes) were included. Average time between RR and cataract surgery was 665 days (median: 546). Early postoperative incidence of cataracts occurred in 19 eyes (46.3%). Types of lens extraction included phacoemulsification with intraocular lens (86.1%, 31/36 dogs), phacoemulsification alone (11.1%, 4/36 dogs), and intracapsular lens extraction (2.8%, 1/36 dogs). Visual improvement occurred in 95.1% of eyes (39/41) immediately postoperatively. Long term, 93.9% of eyes (31/33) maintained vision at 1 month, 85.2% of eyes (23/27) at 3 months, 77.3% of eyes (17/22) at 6 months, and 60% (12/20) at 12 months postoperatively. The most common postoperative complications were glaucoma (29.3%, 12/41 eyes), corneal ulceration (24.4%, 10/36 eyes), fibrin formation (21.9%, 9/41 eyes), and silicone oil migration into the anterior chamber (19.5%, 8/41 eyes). CONCLUSION: Post-RR cataract surgery should be considered in dogs with vision loss from cataracts after RR. In most eyes, vision was maintained up to 1 year postoperatively.

Retinal detachment secondary to vitreoretinopathy in two closely related warmblood horses.

BACKGROUND: To describe the clinical, diagnostic imaging, and histopathological findings of two visually impaired closely related horses and to identify a possible cause. CASE DESCRIPTION: Two warmblood horses, with a common dam and sire, were presented to the ophthalmology department of Liège for investigation of impaired vision. Information collected included physical and ophthalmic examination findings, results of ocular ultrasound, electroretinogram, magnetic resonance imaging (MRI), and histopathology. Ophthalmic examination, ocular ultrasound and MRI revealed a complete retinal detachment (RD) in the left eye and vitreous synaeresis in both eyes of both horses. Electroretinograms showed a normal response in both right eyes but a total loss of the retinal response in their left eyes. Histopathologic examination revealed multifocal retinal dysplasia in both left eyes. CONCLUSION: In these two horses, RD has likely been caused by the congenital posterior segment abnormalities of the vitreous and the retina. A vitreoretinopathy is highly suspected and is possibly hereditary in these closely related siblings.

In vivo imaging comparison of unilateral circular retinal plaques in retriever dogs to dysplasia and detachment in the English Springer Spaniel.

PURPOSE: To compare the scanning laser ophthalmoscopy (SLO), optical coherence tomography (OCT), and fluorescein angiography (FA) findings in retrievers with a single unilateral circular retinal plaque to those of an English springer spaniel with bilateral retinal dysplasia. PROCEDURES: A retrospective record review identified three dogs with circular retinal plaques that underwent SLO and OCT; in two of the three dogs, FA was also completed. Morphologic changes, lesion measurements, and angiogram characteristics were documented. An English springer spaniel with bilateral retinal dysplasia that had undergone SLO, OCT, and FA was used for comparison. RESULTS: Scanning laser ophthalmoscopy of the retriever dogs revealed circular retinal plaques with a dark periphery located in the tapetal retina. OCT revealed a thickening of the nerve fiber layer corresponding to the circular pattern observed on SLO. Within the circular plaque, the retina was predominantly of normal architecture. FA revealed variable hypofluorescence of both the rim and the center of the circular lesion throughout the early angiogram phases. In the late recirculation phase, small multifocal areas of hyperfluorescence were observed. OCT of geographic retinal dysplasia in the English springer spaniel revealed disorganization of both inner and outer retinal layers, and retinal detachment. CONCLUSIONS: Circular plaques observed in the tapetal retina are predominantly formed by a thickening of inner retina, while retinal dysplasia has disorganization of both inner and outer retinal layers. Further etiologic research is needed, including pedigree mapping to determine whether retinal plaques are an acquired or inherited condition.

Evaluation of vitreous degeneration as a potential risk factor for retinal detachment after phacoemulsification in dogs.

PURPOSE: To evaluate vitreous degeneration as a potential risk factor for retinal detachment in dogs after phacoemulsification. METHODS: Medical records for dogs with preoperative ocular ultrasound and phacoemulsification between September 28, 2006, and August 2, 2016, were reviewed. Ultrasound images were reviewed by two observers independently, and vitreous echogenicity was graded using an established scale. The following factors were compared between eyes with and without retinal detachment: signalment, operated eye, cataract stage at the time of surgery, and presence or absence of the following: lens-induced uveitis (LIU), glaucoma, anterior vitreous presentation, lens subluxation, history of prophylactic retinopexy, diabetes mellitus, operating surgeon, concurrent prophylactic retinopexy, posterior capsular tear, phacoemulsification duration, use of automated anterior vitrectomy, placement of an artificial intraocular lens, and intraocular lens type (polymethyl methacrylate or acrylic foldable). Total follow-up time was recorded. Presence and time from surgery to onset of complications were recorded. Retinal detachment was diagnosed based on observation via indirect ophthalmoscopy or ocular ultrasound. RESULTS: Evaluation for association between vitreous degeneration and retinal detachment included 290 eyes of 180 dogs. There was no statistically significant correlation between vitreous degeneration and postoperative retinal detachment. Retinal detachment was observed in 17 of 290 eyes (5.9%). Vitreous degeneration was marked as present by at least one observer in 189 of 290 eyes (65%). CONCLUSIONS: Ultrasonically identifiable vitreous degeneration does not correlate with increased risk of retinal detachment following phacoemulsification.

Clinical, histopathological and genetic characterisation of oculoskeletal dysplasia in the Northern Inuit Dog.

Seven Northern Inuit Dogs (NID) were diagnosed by pedigree analysis with an autosomal recessive inherited oculoskeletal dysplasia (OSD). Short-limbed dwarfism, angular limb deformities and a variable combination of macroglobus, cataracts, lens coloboma, microphakia and vitreopathy were present in all seven dogs, while retinal detachment was diagnosed in five dogs. Autosomal recessive OSD caused by COL9A3 and COL9A2 mutations have previously been identified in the Labrador Retriever (dwarfism with retinal dysplasia 1-drd1) and Samoyed dog (dwarfism with retinal dysplasia 2-drd2) respectively; both of those mutations were excluded in all affected NID. Nine candidate genes were screened in whole genome sequence data; only one variant was identified that was homozygous in two affected NID but absent in controls. This variant was a nonsense single nucleotide polymorphism in COL9A3 predicted to result in a premature termination codon and a truncated protein product. This variant was genotyped in a total of 1,232 dogs. All seven affected NID were homozygous for the variant allele (T/T), while 31/116 OSD-unaffected NID were heterozygous for the variant (C/T) and 85/116 were homozygous for the wildtype allele (C/C); indicating a significant association with OSD (p = 1.41x10-11). A subset of 56 NID unrelated at the parent level were analysed to determine an allele frequency of 0.08, estimating carrier and affected rates to be 15% and 0.6% respectively in NID. All 1,109 non-NID were C/C, suggesting the variant is rare or absent in other breeds. Expression of retinal mRNA was similar between an OSD-affected NID and OSD-unaffected non-NID. In conclusion, a nonsense variant in COL9A3 is strongly associated with OSD in NID, and appears to be widespread in this breed.

Persistent hyperplastic primary vitreous in two piglets.

Two Large Yorkshire piglets were diagnosed as persistent hyperplastic primary vitreous (PHPV). In case 1, the white cord-like structure extending from optic disc to lens was observed in the normal-sized right eye. Case 2 showed buphthalmos of the right eye. The internal structure of the right eye was unclear due to bleeding, but a white cord-like structure was slightly observed. In both cases, histological examinations revealed the fibrovascular cord-like structure in hyaloid vitreous. The retina was detached, and dysplastic nervous tissue was observed in anterior vitreous. Immunohistochemistry using various neural markers suggested that dysplastic nervous tissue was derived from the detached neural retina. By the characteristic macroscopic and histopathological features, both cases were diagnosed as PHPV. To our knowledge, this is the first report of swine PHPV.

Electroretinography is a prognostic indicator for postoperative vision in dogs undergoing retinal reattachment surgery.

PURPOSE: To determine whether pre-operative electroretinography (ERG) predicts postoperative vision in dogs undergoing retinal reattachment surgery (RRS). METHODS: This 18-month prospective study recorded signalment, duration, cause, and extent of retinal detachment and pre-operative vision status. Rod and mixed rod-cone ERG responses were recorded prior to RRS. Referring veterinary ophthalmologists assessed vision 2 months postoperatively. RESULTS: Thirty dogs (40 affected eyes) aged 4 months to 12.1 years were included. The detachment extent was 150° -320° in 15 of 40 eyes, 360° in 24 of 40 eyes, and not recorded in one eye. Most dogs had a genetic predisposition for retinal detachment. Eight eyes of seven dogs had previous cataract surgery. Mean estimated duration of detachment prior to surgery was 24.5 ± 19.6 days. Pre-operatively, 34 of 40 eyes were blind, two of 40 eyes were sighted, and four of 40 eyes had severely diminished vision. Compared to normative ERG values in our clinics, pre-operative ERGs were classified as "normal" in five of 40 eyes, "attenuated" in seven of 40 eyes, and "flat" in 28 of 40 eyes. Following RRS, the retina was fully reattached in all operated eyes. Two-month postoperatively, 30 of 40 eyes had "normal" vision as defined by referring veterinary ophthalmologists, six of 40 eyes had "limited" or "diminished" vision and four of 40 eyes were blind. Normal vision was regained in 12 of 12 (100%) of eyes with normal or attenuated pre-operative ERG's, but only in 18 of 28 (64%) of eyes with flat pre-operative ERG 's (Linear-by-linear test, P = 0.029). CONCLUSIONS: A recordable pre-operative ERG, even if attenuated, is associated with return of vision in canine RRS patients, and is a favorable prognostic indicator.