Major breed distribution of canine patients enucleated or eviscerated due to glaucoma following routine cataract surgery as well as common histopathologic findings within enucleated globes

Comparison of Postoperative Intraocular Inflammation in Dogs Receiving Transzonular Intravitreal Triamcinolone-Moxifloxacin Versus Subconjunctival Triamcinolone After Phacoemulsification

OBJECTIVE

To evaluate the postoperative effect of transzonular intravitreal triamcinolone-moxifloxacin compared to subconjunctival triamcinolone administered during phacoemulsification in dogs.

ANIMALS STUDIED

Forty-eight dogs (96 eyes) undergoing bilateral phacoemulsification and intraocular lens implantation.

PROCEDURES

All dogs undergoing phacoemulsification and intraocular lens implantation received transzonular intravitreal triamcinolone-moxifloxacin (TITM) in one eye and subconjunctival triamcinolone (SCT) in the contralateral eye. Aqueous flare (AF), anterior chamber fibrin formation (FF), pigment precipitates (PP) on the intraocular lens, posterior capsular opacification (PCO), corneal edema (CE), and intraocular pressure (IOP) were assessed 1 day, 1 week, 2-3 weeks, 4-6 weeks, 8-12 weeks, and ≥ 3 months postoperatively.

RESULTS

There was no difference in AF over time (p > 0.05); however, at 2-3 weeks postoperatively, the average AF was statistically greater (p = 0.01) in the TITM group compared to the SCT group. At three postoperative time points, IOP was significantly different (p < 0.05) between TITM and SCT eyes, but remained within a normal reference range. In both groups, IOP significantly decreased (p < 0.05) over time.

CONCLUSIONS

In the parameters evaluated, including overall visual outcome and surgical success, no clinically relevant differences between groups were appreciable. TITM and SCT, used adjunctively to postoperative topical ophthalmic and oral anti-inflammatories, appear to be acceptable techniques for administering a local ocular corticosteroid during canine phacoemulsification, but whether they provide any synergistic or additive effect remains unclear.

Development of Postoperative Ocular Hypertension After Phacoemulsification for Removal of Cataracts in Dogs

A cataract is a disease in which the lens of the eye becomes clouded, causing a partial or complete loss of vision. Phacoemulsification (PHACO) is a modern surgical technique used in cataract surgery. Study findings: This study observed changes in intraocular pressure (IOP) after surgery in 31 dogs (48 eyes) with cataracts that visited a veterinary hospital. The procedure involved a lens extraction by PHACO and the implantation of an intraocular lens (IOL). Postoperative ocular hypertension (POH) was defined as a postoperative IOP of 25 mmHg or higher. To assess changes in IOP, IOP measurements were performed at 1, 2, 3, and 20 h, and at 1, 2, 3, 4, and 8 weeks after surgery. The IOP was found to be significantly higher at 1 (p < 0.05), 2 (p < 0.01), and 3 (p < 0.01) hours postoperatively compared with preoperatively. The IOP measurements were compared by dividing them into three groups according to the observation period. The IOP values were measured for three groups: before cataract surgery (Group A: 13.10 ± 8.29 mmHg), 1 to 3 h after cataract surgery (Group B: 17.84 ± 5.33 mmHg), and 20 h to 8 weeks after surgery (Group C: 13.71 ± 4.78 mmHg). The IOP values from 1 to 3 h after surgery (Group B) were significantly higher compared to both Group A (p < 0.01) and Group C (p < 0.001). Conclusions: It is suggested that POH occurring within 0 to 3 h after cataract surgery should be diagnosed as secondary glaucoma, and treatment should be performed accordingly.

Stem Cell-Based Therapies for Glaucoma Treatment: A Review Bridging the Gap in Veterinary Patients

Retinal diseases are characterized by progressive damage to retinal cells, leading to irreversible vision loss. Among these, glaucoma stands out as a multifactorial neurodegenerative disease involving elevated intraocular pressure, retinal ganglion cell apoptosis, and optic nerve damage, ultimately resulting in blindness in both humans and dogs. Stem cell-based therapies have emerged as a promising therapeutic option for such conditions due to their regenerative and neuroprotective potential. These therapies, particularly those based on mesenchymal stem cells, offer the potential to repair and protect retinal tissues through the bioactive molecules (growth factors, cytokines, chemokines) secreted, their secretome. However, research in this field, especially on the use of umbilical cord mesenchymal stem cells' secretome, remains sparse. Most clinical trials focus on human glaucomatous patients, leaving a significant gap in veterinary patients' application, especially in dogs, with additional research being needed to determine its usefulness in canine glaucoma treatment. Future studies should aim to evaluate these therapies across both human and veterinary contexts, broadening treatment possibilities for glaucoma.

Evaluation of ciliary cleft changes after phacoemulsification using ultrasound biomicroscopy in dogs with cataracts

Introduction

Glaucoma is one of the most serious complications that causes irreversible blindness after phacoemulsification in dogs; however, a clear mechanism has not been elucidated. This study aimed to analyse the possible anatomical factors associated with glaucoma after phacoemulsification using parameters that reflect the anatomical characteristics of dogs.

Materials and methods

A total of 69 eyes of 48 dogs were included in this study. The patients were divided into three groups: normal eye (n = 18), cataract (n = 39), and post-phacoemulsification for at least 2 months after surgery (post-phaco, n = 12). For further analysis, the dogs were subdivided into two groups according to cataract stage: phacoemulsification non-candidate and candidate groups. Non-cataracts and incipient cataracts were categorized into the non-candidate group, whereas immature and mature cataracts were categorized into the candidate group. Measurements of the ciliary cleft parameters, including the area of the ciliary cleft (CCA), length of the ciliary cleft (CCL), width of the ciliary cleft (CCW), iridocorneal angle, and angle opening distance, were obtained using ultrasound biomicroscopy.

Results

CCA, CCL, and CCW were significantly higher in the candidate group than in the non-candidate group. CCA, CCL, and CCW were significantly reduced in the post-phaco group compared to those in the cataract group. Based on these results, we found that the ciliary cleft expanded in cataract-affected eyes and narrowed after phacoemulsification. This may indicate that the space between the trabecular meshworks became narrower, potentially leading to an increase in the resistance of the aqueous humor.

Conclusion

A narrowed ciliary cleft after phacoemulsification may be an anatomical factor associated with glaucoma.

Diagnostic Tests Used During the Ocular Examination

This article provides a review of the required ocular tests during the ophthalmologic examinations of canine and feline patients. Knowledge of medications affecting ocular parameters and awareness of available instrumentation and test materials is essential for accurate diagnoses.

Prophylactic efficacy of intravenous paracetamol administration to reduce the incidence of post-operative ocular hypertension in dogs undergoing phacoemulsification: A pilot study

PURPOSE

To determine whether intravenous administration of paracetamol can prevent postoperative ocular hypertension (POH) in dogs following routine phacoemulsification.

METHODS

Diabetic and non-diabetic patients (total 54 dogs) undergoing unilateral or bilateral phacoemulsification were recruited to this placebo-controlled, prospective study. The control group received 1 ml/kg saline via intravenous infusion while the treatment group received 10 mg/kg paracetamol via intravenous infusion. Infusions were administered 30 min prior to surgery and repeated 12 h following initial administration. All patients received topical latanoprost at the conclusion of surgery. Intraocular pressure (IOP) was measured before premedication (baseline), and at 1 h, 3 h, 5 h and 18 h following extubation. POH was defined as an IOP above 25 mmHg (POH25). In addition, the number of patients with an IOP exceeding 20 mmHg was analyzed (POH20).

RESULTS

POH20 occurred in 33 of 54 animals (61.1%), including 19 of 25 animals (76.0%) in the control group and 14 of 29 animals (55.2%) in the treatment group. POH25 occurred in 23 of 44 animals (52.3%), including 13 of 25 animals (52.0%) in the control group and 10 of 29 animals (34.5%) in the treatment group. Paracetamol administration showed a significant positive effect on reducing the incidence of POH20 (p = .048), but not POH25 (p = .221).

CONCLUSIONS

When comparing groups, treatment with paracetamol showed a statistically significant reduction in the incidence of POH20, although no differences were observed in the incidence of POH25 between groups. Further studies are warranted to explore whether alternative drug regimes or routes of administration can provide enhanced efficacy in the prevention of POH25.

Retrospective Study of Long-Term Outcome of Phacoemulsification in 22 Feline Eyes with Presumed Congenital/Juvenile Cataracts (2007-2020)

The objective of this study was to determine the complication risk and prevalence after phacoemulsification in cats with presumed congenital/inherited cataracts. Twelve client-owned cats were included in the study. This retrospective study spanned 13 yr and involved 22 eyes. The median age at the time of surgery was 15 mo (range: 4.5-168 mo of age). Recorded complications were 3 eyes developed postoperative ocular hypertension, 1 eye developed glaucoma, 7 eyes developed feline herpes virus-1 signs, and 7 eyes developed postoperative uveitis >2 wk after surgery. No eyes had developed intraocular sarcomas at the time of their last exam. All eyes remained visual at last follow-up (range: 0.5-121 mo). Success was defined as a comfortable and visual eye without intraocular neoplasia, glaucoma, a partial or complete retinal detachment, or uveitis that occurred >2 wk after surgery or persisted longer than 2 wk. Twenty-one out of 22 eyes had a successful outcome. In this study, cats with presumed congenital/juvenile cataracts who underwent phacoemulsification had an excellent outcome.

Retrospective evaluation of phacoemulsification and aspiration in 182 eyes: Visual outcomes and CDE-predictive value

OBJECTIVE

To determine the effect of cumulative dissipated energy (CDE) on complications and visual outcome following cataract surgery in dogs.

ANIMALS STUDIED

Records of 182 canine eyes that had undergone cataract surgery.

PROCEDURES

Retrospective medical record review was conducted on dogs that underwent unilateral or bilateral elective cataract surgery by a single surgeon. Preoperative variables such as age, cataract duration, and pre-existing conditions were recorded. Intraoperative variables such as intraocular lens (IOL) status, phacoemulsification time, average power, irrigation fluid volume, and CDE were recorded. Postoperative complications and visual status at last follow-up were compared to these variables.

RESULTS

Eighty-six percent of dogs were visual in one or both eyes at last follow-up (LFU) examination. Median follow-up time was 186 days postoperatively. Eyes that developed glaucoma had a significantly greater mean CDE (77.73 ± 80.11) than eyes that did not develop glaucoma (49.21 ± 38.93). Eyes that remained visual at the LFU examination had a significantly lower mean CDE (48.31 ± 37.14) than eyes that were blind at LFU (82.05 ± 82.73). Significantly lower mean CDEs were found in diabetic eyes, younger eyes, early-operated eyes (<1 month duration), and eyes with preoperative lens-induced uveitis.

CONCLUSIONS

Higher CDE may be associated with an increased risk of postoperative glaucoma and loss of vision in dogs. Cumulative dissipated energy may be a useful prognostic indicator for success of canine cataract surgery.

Looking into the future: Gene and cell therapies for glaucoma

Glaucoma is a complex group of optic neuropathies that affects both humans and animals. Intraocular pressure (IOP) elevation is a major risk factor that results in the loss of retinal ganglion cells (RGCs) and their axons. Currently, lowering IOP by medical and surgical methods is the only approved treatment for primary glaucoma, but there is no cure, and vision loss often progresses despite therapy. Recent technologic advances provide us with a better understanding of disease mechanisms and risk factors; this will permit earlier diagnosis of glaucoma and initiation of therapy sooner and more effectively. Gene and cell therapies are well suited to target these mechanisms specifically with the potential to achieve a lasting therapeutic effect. Much progress has been made in laboratory settings to develop these novel therapies for the eye. Gene and cell therapies have already been translated into clinical application for some inherited retinal dystrophies and age-related macular degeneration (AMD). Except for the intravitreal application of ciliary neurotrophic factor (CNTF) by encapsulated cell technology for RGC neuroprotection, there has been no other clinical translation of gene and cell therapies for glaucoma so far. Possible application of gene and cell therapies consists of long-term IOP control via increased aqueous humor drainage, including inhibition of fibrosis following filtration surgery, RGC neuroprotection and neuroregeneration, modification of ocular biomechanics for improved IOP tolerance, and inhibition of inflammation and neovascularization to prevent the development of some forms of secondary glaucoma.

Association between preoperative gonioscopic status and postoperative glaucoma after phacoemulsification in dogs: A retrospective cohort study of 505 eyes

OBJECTIVE

To assess whether preoperative gonioscopy status is associated with the development of postoperative glaucoma after phacoemulsification.

PROCEDURE

Eligible dogs and eyes were selected from medical records (2007-2017), and each eye was classified as having normal or abnormal gonioscopy status. Records were examined for postoperative glaucoma, and data were collected for baseline variables including patient signalment, surgical factors, and pre, intra, and postoperative medications.

RESULTS

Of 305 dogs (505 eyes) selected for review in this study, 111 dogs (163 eyes) had abnormal gonioscopy findings, and 194 dogs (342 eyes) had normal gonioscopy findings. Postoperative glaucoma occurred in 24% (39/163) of eyes with abnormal gonioscopy and in 14% (49/342) eyes with normal gonioscopy. Eyes with abnormal gonioscopy status were at higher risk of postoperative glaucoma compared to normal eyes (P = .025). There was no important confounding due to the numerous baseline variables summarised above. Regardless of gonioscopy status, the risk of glaucoma was highest during the first 2 months after surgery.

CONCLUSIONS

Eyes with abnormal gonioscopy findings are at increased risk of postoperative glaucoma compared with eyes with normal gonioscopy findings. Gonioscopy is recommended as a part of presurgical assessment in all dogs prior to phacoemulsification. Further study is needed to assess whether the incidence of postoperative glaucoma can be reduced by increased monitoring or altered treatment protocols in cases that are known to have abnormal gonioscopy findings prior to cataract surgery.

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.

Preliminary report of postoperative complications of phacoemulsification in Pugs: A multicenter retrospective study of 32 cases

OBJECTIVE

To compare complication rates and visual outcomes following phacoemulsification in Pugs versus dogs of other breeds.

ANIMALS STUDIED

Thirty-two pure-bred Pugs (55 eyes) and 32 dogs of other breeds (56 eyes) undergoing phacoemulsification.

PROCEDURES

Multi-institutional retrospective medical record review of perioperative factors, postoperative complications, and visual outcomes. The reference population of dogs of varying breeds included surgical cases following each Pug case at the same institutions. Perioperative risk factors and postoperative complication rates were compared between the two populations.

RESULTS

Pigmentary keratitis and diabetes mellitus were the most common preoperative comorbidities, found in 75% (P < .001) and 72% (P = .12) of Pugs, respectively. No perioperative factors were significantly associated with postoperative complications in Pugs. Postoperative complication rates were similar between groups; however, the most common complication in Pugs was corneal ulceration (15% of operated eyes), whereas glaucoma was most common in the reference population (13% of operated eyes). Three months postoperatively, vision was preserved in 91% of eyes of Pugs (50/55) and 95% of the reference population (53/56). One year postoperatively, 80% (32/40) of Pug eyes and 82% (28/34) of eyes in the reference population remained sighted.

CONCLUSIONS

Comorbidities and complications of cataract surgery in Pugs of this study demonstrate a predisposition for corneal disease. This highlights the importance of preoperative evaluation of factors associated with PK and corneal clarity, and postoperative monitoring for corneal ulceration in this breed.

The future of canine glaucoma therapy

Canine glaucoma is a group of disorders that are generally associated with increased intraocular pressure (IOP) resulting in a characteristic optic neuropathy. Glaucoma is a leading cause of irreversible vision loss in dogs and may be either primary or secondary. Despite the growing spectrum of medical and surgical therapies, there is no cure, and many affected dogs go blind. Often eyes are enucleated because of painfully high, uncontrollable IOP. While progressive vision loss due to primary glaucoma is considered preventable in some humans, this is mostly not true for dogs. There is an urgent need for more effective, affordable treatment options. Because newly developed glaucoma medications are emerging at a very slow rate and may not be effective in dogs, work toward improving surgical options may be the most rewarding approach in the near term. This Viewpoint Article summarizes the discussions and recommended research strategies of both a Think Tank and a Consortium focused on the development of more effective therapies for canine glaucoma; both were organized and funded by the American College of Veterinary Ophthalmologists Vision for Animals Foundation (ACVO-VAF). The recommendations consist of (a) better understanding of disease mechanisms, (b) early glaucoma diagnosis and disease staging, (c) optimization of IOP-lowering medical treatment, (d) new surgical therapies to control IOP, and (e) novel treatment strategies, such as gene and stem cell therapies, neuroprotection, and neuroregeneration. In order to address these needs, increases in research funding specifically focused on canine glaucoma are necessary.

Caracterização clínica e histopatológica de bulbos oculares de cães e gatos (2005-2015)

RESUMO: Objetivou-se realizar a caracterização clínica e histopatológica de bulbos oculares de cães e gatos, removidos cirurgicamente por indicação clínica, no período entre 2005-2015. Foram realizados 101 procedimentos de remoção do bulbo ocular, 93 enucleações (92%) e 8 exenterações (8%). Os procedimentos foram realizados em 80 cães, (79% dos casos) e em 21 gatos (21% dos casos). Os cães submetidos à intervenção cirúrgica apresentavam perfurações oculares (n=31, 39%), glaucoma (n=19, 24%), protrusão ocular (n=13, 16%), diagnósticos sugestivos de neoplasia (n=10, 12,5%) e outros (n=3, 2,97%). Dentre os gatos os diagnósticos clínicos compreenderam perfuração ocular (n=9, 49%), glaucoma (n=3, 14,2%), microftalmia (n=3, 14,2%), sugestivo de neoplasia (n=2, 9,5%), protrusão ocular (n=2, 9,5%) e outros (n=2, 9,5%). Vinte e sete amostras de bulbos oculares foram submetidas para avaliação histopatológica, sendo 23 provenientes de cães e quatro de gatos. Dentre as amostras de origem canina, sete exibiram achados histopatológicos compatíveis com glaucoma, sete perfurações oculares, seis neoplasias intraoculares, duas panoftalmites e um quadro de Phthisis bulbi. Nos bulbos oculares de gatos foram diagnosticadas duas neoplasias intraoculares, uma microftalmia e uma perfuração ocular. Constatou-se que o glaucoma secundário, as neoplasias e as perfurações oculares estão entre as principais causas de enucleação em cães, e associadas a alterações primárias como a ceratoconjuntivite seca e as uveítes. Estas afecções, diferentemente das neoplasias, podem ter êxito terapêutico mediante diagnóstico e tratamento precoces, prevenindo a cegueira e a remoção do bulbo ocular.

Lens-Related Emergencies: Not Always So Clear

Emergencies involving the crystalline lens are not common; however, their clinical signs must be recognized quickly to begin treatment or referred immediately to improve the chances of retaining sight. The lens is a unique structure because of its immunologically privileged status and its imperative clarity for vision. Any insult to the lens capsule's integrity, its position within the globe, or to its clarity may result in undesirable sequelae.