Evaluation of client perceptions concerning outcome of cataract surgery in dogs

OBJECTIVE: To compare client perception of outcome of phacoemulsification in dogs with information obtained from medical records. DESIGN: Retrospective cohort study. ANIMALS: 108 dogs (203 eyes) undergoing phacoemulsification from May 1999 through April 2004. PROCEDURE: Data obtained from medical records included signalment, presence of diabetes mellitus, cataract stage, whether surgery was unilateral or bilateral, intraocular lens (IOL) placement, and postoperative complications. Owners completed a survey concerning outcome of phacoemulsification in their dog. Survey responses from owners classified as satisfied or dissatisfied with the outcome of phacoemulsification on the basis of their willingness, in retrospect, to have the surgery performed again were compared. RESULTS: Data from medical records and survey responses were available for 108 dogs (203 eyes). Median follow-up was 3 months via medical record review and 12 months via owner survey responses. Most (81%) owners were satisfied with outcome. The most common reason for dissatisfaction was loss of vision after surgery; however, most dissatisfied owners did not return their dog for examinations. Owner perception of success was not associated with patient age, sex, presence of diabetes mellitus, cataract stage, or IOL placement in at least 1 eye but was associated with perceived improvement of their pet's vision and activity level. Dissatisfied owners were significantly more likely to report that explanation of risks and complications before surgery was inadequate. CONCLUSIONS AND CLINICAL RELEVANCE: Owner perception of outcome after phacoemulsification in dogs was highly favorable. However, surgical risks and the importance of postoperative examinations, particularly in dogs undergoing visual deterioration, must be conveyed to clients.     

Development of glaucoma after phacoemulsification for removal of cataracts in dogs: 22 cases (1987-1997)

OBJECTIVE: To determine factors contributing to glaucoma after lens extraction via phacoemulsification in dogs. DESIGN: Retrospective study. ANIMALS: 22 dogs (29 eyes) with glaucoma and 21 dogs (30 eyes) without glaucoma after phacoemulsification. PROCEDURE: Medical record review. RESULTS: Eyes at increased risk for glaucoma included those of Boston Terriers, those with uveal or retinal abnormalities before surgery, and those with intraoperative intraocular hemorrhage. Significant differences between groups were not detected for incidence of preoperative lens-induced uveitis, presence of an intraocular lens, or frequency of an acute postoperative increase in intraocular pressure. Glaucoma developed (mean +/- SD) 12.8+/-14.1 months (median, 10 months; range, 0.25 to 55 months) after surgery. Eighteen of 29 (62%) eyes with potential for vision after onset of glaucoma retained vision for a mean of 16.5+/-12.8 months (median, 10.8 months; range, 1.5 to 37 months) after glaucoma was diagnosed. Most of these eyes still had vision at the conclusion of the study period. CONCLUSIONS AND CLINICAL RELEVANCE: Risk factors identified by this study will aid in preoperative counseling of clients and refining selection criteria for candidates for phacoemulsification. Careful follow-up for the remainder of the dog's life after surgery may improve long-term success rates by permitting early intervention before intraocular pressure increases substantially and vision is irreversibly lost. Surgery for cataracts may still be worthwhile in dogs with increased risk of glaucoma, especially if elderly, because of the lengthy period to onset of glaucoma after surgery and the beneficial effects of treatment after glaucoma develops.     

Phacoemulsification and acryl foldable intraocular lens implantation in dogs: 32 cases

This study evaluated the surgical outcome and complications of phacoemulsification and the implantation of an acryl foldable intraocular lens (IOL) with a squared edge in dogs with cataracts. Thirty-two eyes from 26 dogs were examined. The mean follow up period was 75.9 days ranging from 23 to 226 days. The complications after phacoemulsification were posterior capsular opacity (PCO) around the IOL (n = 11), ocular hypertension (n = 4), focal posterior synechia (n = 4), hyphema (n = 3) and corneal ulcer (n = 2). The complications associated with the IOL were decenteration of the optic (n = 2) and ventral haptic displacement (n = 1). Most cases of PCO were found only around the margin of the IOL, and all eyes had vision during the observation period. In conclusion, the implantation of an acryl-foldable lens with a squared edge at the time of phacoemulsification is an effective method for preserving the central visual field of dogs with cataract.     

Development of glaucoma after cataract surgery in dogs: 220 cases (1987-1998)

OBJECTIVE: To examine postoperative ocular hypertension (POH) and other variables as predictors of the risk of developing glaucoma after cataract surgery in dogs. DESIGN: Retrospective study. ANIMALS: 220 dogs that had cataract surgery. PROCEDURE: Medical records of 220 dogs (346 eyes) that had extracapsular cataract removal or phacoemulsification of cataracts were reviewed. With respect to glaucoma development, 8 variables were analyzed, which included development of POH, breed, sex, age at time of surgery, eye (right vs left), phacoemulsification time, intraocular lens (IOL) placement (yes or no), and stage of cataract development. Eyes developed glaucoma within 6 or 12 months of surgery or did not have signs of glaucoma at least 6 or 12 months after cataract surgery. RESULTS: Of 346 eyes, 58 (16.8%) developed glaucoma after surgery. At 6 months, 32 of 206 (15.5%) eyes examined had glaucoma; at 12 months, 44 of 153 (28.8%) eyes examined had glaucoma. Median follow-up time was 5.8 months (range, 0.1 to 48 months). Mixed-breed dogs were at a significantly lower risk for glaucoma, compared with other breeds. Eyes with IOL placement were at a significantly lower risk for glaucoma, compared with eyes without IOL placement. Eyes with hypermature cataracts were at a significantly higher risk for glaucoma, compared with eyes with mature or immature cataracts. CONCLUSIONS AND CLINICAL RELEVANCE: Multiple factors appear to contribute to the onset of glaucoma in dogs after cataract surgery. Complications prohibiting IOL placement during cataract surgery may lead to a high risk of glaucoma development.     

Evaluation of risk factors for development of secondary glaucoma in dogs: 156 cases (1999-2004)

OBJECTIVE: To determine the immediately antecedent cause of secondary glaucoma and the prevalence of secondary glaucoma with anterior uveitis or lens dislocation in dogs. DESIGN: Retrospective case series. ANIMALS: 156 dogs with secondary glaucoma. PROCEDURES: Cause of glaucoma was determined from records. Breed, age, sex, and neuter status of all dogs with secondary glaucoma were compared with the general hospital population. The prevalence of secondary glaucoma in dogs with a primary diagnosis of lens dislocation or anterior uveitis during the same period was determined. RESULTS: Secondary glaucoma was diagnosed in 156 of 2,257 (6.9%) dogs examined because of ophthalmic disease and was bilateral in 33 (21.2%) of those dogs. In 31 (94%) bilaterally affected dogs, the antecedent cause was the same in both eyes. Common causes of secondary glaucoma were non-surgical anterior uveitis (44.9%), anterior uveitis associated with prior phacoemulsification (15.8%), and lens dislocation (15.2%). Parson Russell Terriers, Poodles, Boston Terriers, Cocker Spaniels, Rhodesian Ridgebacks, and Australian Cattle Dogs had diagnoses of secondary glaucoma more often than expected, compared with the reference population. Age, sex, neuter status, and laterality were not associated with secondary glaucoma. The prevalence of secondary glaucoma in dogs with lens dislocation or uveitis was 15% or 17%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Glaucoma develops secondary to many intraocular diseases, particularly uveitis and lens dislocation. Diagnosis of these diseases should prompt frequent monitoring of intraocular pressure, regardless of signalment.     

Secondary glaucomas in the dog in North America

OBJECTIVE: To determine the prevalence of secondary glaucomas in dogs associated with cataract formation, lens luxation or displacement, cataract surgery, uveitis, hyphema and intraocular neoplasia. METHODS: Information was obtained from the Veterinary Medical Data Base (VMDB) from all veterinary medical teaching hospitals in North America from March 1964 to March 2003. Secondary glaucomas were diagnosed at the same examination or after the primary diagnosis was made, and included those associated with cataract formation, lens luxation, cataract surgery, uveitis of unknown cause, hyphema of unknown cause, and intraocular neoplasia. The data were evaluated by decade, breed, gender and age of presentation. RESULTS: A total of 1 592 831 dogs were presented, and 9695 canine secondary glaucomas. Secondary glaucoma associated with cataract formation represented 81% of all the canine secondary glaucomas. Breeds (n = 7890 dogs) predisposed to secondary glaucoma and cataracts had an overall prevalence of 0.5%, but nearly 20% of all the cataractous dogs developed secondary glaucoma in at least one eye. For the years 1994-2003, these breeds included the American Cocker Spaniel; Boston Terrier; Toy, Miniature and Standard Poodle; English Springer Spaniel; Bichon Frise; and Labrador Retriever. The other forms of secondary glaucoma occurred less frequently, and included those glaucomas with lens luxation or displacement (779 dogs; 12.0%), postcataract surgery (528 dogs; 5.1%), with uveitis from unknown cause (399 dogs; 7.1%), with hyphema from unknown cause (117 dogs; 7.3%), and with intraocular neoplasia (19 dogs; 3.5%). The risk of the secondary glaucomas from 1984 to 2002 was highest after the intracapsular lens extraction (ICLE), less in the extracapsular technique (ECLE), and lowest for the phacoemulsification/phacofragmentation method. CONCLUSION: Prevalence of the canine secondary glaucomas ranges from 0.25% (1964-1973), 0.46% (1974-1983), 0.79% (1984-1993), to 0.80% (1994-2003) and are as frequent as the primary or breed-related glaucomas during these same time periods.     

Intracapsular lensectomy and sulcus intraocular lens fixation in dogs with primary lens luxation or subluxation

Objective  To evaluate the postoperative results of lensectomy and sulcus intraocular lens fixation (SIOLF) via an ab interno approach in dogs with progressive lens subluxation or early luxation.
Study design  Retrospective study.
Animals studied  Twenty eyes from 19 dogs presented to the Animal Eye Clinic for lens luxation or subluxation between 1999 and 2006.
Methods  Medical records were reviewed to evaluate preoperative lens position, vision status, intraocular pressure (IOP), and whether surgery was performed on an emergent or elective nature. Lensectomy and SIOLF were performed and postoperative status including vision, glaucoma, and retinal detachment was assessed.
Results  Average age was 8.6 years (range 4–14 years) and 55% (11/20) were terriers. Patients were followed a mean of 29.2 months (range 1–92 months) after surgery. Retinal detachment or secondary glaucoma was observed in 1 of 20 (5%) and 5 of 20 (20%) eyes, respectively, with 1 of 20 (5%) exhibiting both. Mean preoperative IOP was 16 mmHg and preoperative lens position was equally divided between luxated and subluxated lenses. Surgery was performed more frequently as an elective procedure (18/20; 90%) due to normalized IOP vs. an emergency procedure (2/20; 10%). Vision was retained in 70% (14/20) of eyes with a mean time to vision loss of 41 months in the remaining eyes due to glaucoma, retinal detachment, or retinal degeneration.
Conclusions  Complications of glaucoma and retinal detachment after SIOLF in this study were less when compared with previously reported incidence rates in the literature for lensectomy alone which may reflect improved patient selection.     

The incidence of posterior capsule disruption during phacoemulsification and associated postoperative complication rates in dogs: 244 eyes (1995-2002)

OBJECTIVE: The objective of this retrospective study was to report the incidence of posterior capsule disruption during routine phacoemulsification and to document the postoperative outcomes and complications in eyes with posterior capsule disruption compared with eyes with intact posterior capsules. PROCEDURES: Records of 143 dogs (244 eyes) were reviewed. Data collected included whether the posterior capsule was disrupted, whether the disruption was planned or accidental, whether an intraocular lens was implanted, and visual outcome. Records were reviewed for postoperative complications. Intraocular lens implantation rates, complication rates, and visual outcomes were compared between intact and disrupted posterior capsule groups using Chi-square analyses. RESULTS: The posterior capsule was disrupted in 33/244 eyes (14%). Planned capsulotomies accounted for 36% of the disruptions. Intraocular lenses were implanted in 76% of eyes without a disruption of the posterior capsule and in 31% of eyes with a posterior capsule disruption. Intraocular lenses were more likely to be implanted in eyes with a planned disruption of the posterior capsule (7/12; 58%) than in eyes with an accidental disruption (3/20; 15%). There were no significant differences in postoperative complications or visual outcome between eyes with posterior capsule disruption and those without. CONCLUSIONS: The most significant complication of posterior capsule disruption during phacoemulsification is the inability to implant an intraocular lens. Intraocular lenses are more likely to be placed in eyes with intentional disruptions of the posterior capsule than those with accidental ruptures.     

Long-term complications after phacoemulsification for cataract removal in dogs: 172 cases (1995-2002)

OBJECTIVE: To determine common postoperative complications and risk factors for development of postoperative glaucoma or failure to preserve vision after phacoemulsification for cataract removal in dogs. Design-Retrospective case series. ANIMALS: 172 dogs (290 eyes) that underwent phacoemulsification surgery for cataract removal. PROCEDURE: Medical records were reviewed for postoperative complications; prevalence rates for each complication were calculated for follow-up periods of 3 months, > 3 to 6 months, > 6 months to 1 year, > 1 to 2 years, > 2 to 3 years, > 3 to 4 years, and > 4 years. Odds ratios for breed, age, sex, cataract hypermaturity, lens-induced uveitis, and diabetes mellitus were determined with respect to glaucoma and failure (ie, blindness, enucleation, or evisceration). RESULTS: The most common complication was mild posterior capsule opacification. Retinal detachment was uncommon (1% to 2%) for all time periods. Prevalence of glaucoma increased with time, although it remained < 10% until after the 1-year follow-up period. Boston Terriers, Cocker Spaniels, Cocker Spaniel-Poodle crosses, and Shih Tzus had increased risk of developing glaucoma. Eyes with hypermature cataracts were more likely to develop glaucoma. Prevalence of failure increased with time, although it remained < 10% until after the 3-year follow-up period. Cocker Spaniel-Poodle cross and Shih Tzus were more likely to have failure. CONCLUSIONS AND CLINICAL RELEVANCE: Evaluation of breed and cataract hypermaturity may aid in the selection of patients. The increasing prevalence of postoperative complications with time indicated that longterm monitoring is warranted.     

Phacofragmentation and aspiration for cataract extraction in dogs: 56 cases (1980-1984)

Fifty-six cases of cataract removal in dogs by phacofragmentation and aspiration were reviewed. Improvement of vision was detected in the immediate postoperative period in 53 (94.6%) of 56 dogs. Vision was present in 25 (85.2%) of 29 dogs evaluated at 2 years after surgery, and in 5 (71.4%) of 7 dogs evaluated 4 years after surgery. Reasons for failure of visual improvement and complications in visual eyes were related primarily to development of postoperative anterior uveitis. Age of the dog at surgery was not a significant factor in the restoration of vision.     

Long‐term outcome after implantation of a suprachoroidal cyclosporine drug delivery device in horses with recurrent uveitis

Objective To determine the long‐term efficacy, complications, and duration of effect of a cyclosporine (CsA) suprachoroidal implant (CSI) in horses with equine recurrent uveitis (ERU). Methods Horses with ERU were treated with a 6‐mm diameter, 25 mg, reservoir matrix CsA implant in the deep sclera adjacent to the suprachoroidal space. Horses with follow‐up >1 year were examined for frequency of uveitis episodes, complications, and vision at last recheck. Results Data from 151 eyes of 133 horses from the USA and Europe that had CsA devices implanted for ERU were reviewed. Follow‐up time ranged from 13 to 85 months after surgery, with a mean and median follow‐up time of 28.9 and 26.3 months, respectively. Overall, at last follow‐up 78.8% of eyes were considered visual and the overall mean frequency of uveitis episodes after CSI was 0.09 ± SD 0.08 episodes per month. The most common complications leading to vision loss at last follow‐up were persistent uveitis episodes (54%), glaucoma (22%), mature cataracts (16%), and retinal detachment (6%). Persistent uveitis episodes tended to be the highest cause of vision loss in horses with <24 months and >48 months of follow‐up. Conclusions This study demonstrated the long‐term maintenance of vision of horses with ERU implanted with a CSI. The increased vision loss related to uveitis episode of inflammation in eyes after the likely depletion of CsA from the CSI suggests that a repeat CSI may be required at or before 48 months after surgery.     

Canine cataracts, diabetes mellitus and spontaneous lens capsule rupture: a retrospective study of 18 dogs

OBJECTIVE: To describe the clinical presentation and surgical outcome of diabetic canine patients with cataracts and preoperative spontaneous lens capsule rupture. ANIMALS STUDIED: A total of 20 dogs and 40 eyes were included in the retrospective evaluation. The patients' ages ranged from 5 to 14 years (mean 8.5 years). RESULTS: All dogs had clinical diabetes mellitus, with the duration since diagnosis ranging from 30 to 240 days (mean 123 days). Cataracts were bilateral and noted to have been present for 14-112 days (mean 39 days). Of the 40 eyes affected with cataracts, 30 had a spontaneous rupture of the lens capsule prior to surgery. The capsular rupture was diagnosed on clinical examination in 28/30 eyes and was noted intraoperatively in 2/30. The location of the capsular rupture was equatorial in 29/30 and posterior in 1/30 eyes. Surgery was performed in 38/40 eyes, with one case lost to follow-up without surgical intervention. Prior to surgery, routine diagnostic ophthalmic examination, ocular ultrasound, electroretinography, and systemic evaluation were performed in all dogs. Surgical procedures included phacoemulsification in 28/40 eyes, with IOL placement performed in 20/28 eyes. Intrascleral prosthesis placement or enucleation was performed in 8/40 and 2/40 eyes, respectively, due to a significantly reduced ERG or secondary glaucoma. CONCLUSIONS: The duration of clinical follow-up (19/20 dogs) ranged from 1 to 36 months (mean 12.9 months). All eyes that had cataract surgery with or without IOL placement were sighted at the time of the last follow-up examination. Spontaneous lens capsule rupture associated with diabetes mellitus, cataract and rapid lens intumescence occurs in the dog. Early surgical intervention, prior to secondary complications of glaucoma and loss of retinal function, is associated with a favorable outcome.     

Clinical features and outcomes of phacoemulsification in 39 horses: a retrospective study (1993-2003)

OBJECTIVE: To identify visual outcome and postoperative complications following phacoemulsification of equine cataracts. ANIMALS: Records of 39 horses (55 eyes) with cataracts were reviewed. METHODS: Eyes with cataracts removed by phacoemulsification were included in the study. Data collected included age, breed, sex, stage and etiology of cataract, unilateral vs. bilateral involvement, and ultrasound findings. Horses were grouped by etiology of the cataract. Visual outcome and complications were evaluated for each group and the overall population. RESULTS: Immediately postoperatively 46 out of 47 eyes (98%) were sighted. Four weeks postoperatively 23 of 29 operated eyes (79%) were sighted [13/18 (72%) eyes with congenital/juvenile onset, 6/6 (100%) eyes with traumatic and 4/5 (90%) eyes with uveitis-induced cataracts], with 18 eyes lost to follow-up. The most common postoperative complications included corneal edema (19 eyes/40%), fibrin in the anterior chamber (11 eyes/23%), postoperative ocular hypertension (9 eyes/19%), synechia/dyscoria (9 eyes/19%), and hyphema (7 eyes/15%). CONCLUSIONS: Prognosis for vision is favorable for horses following phacoemulsification and planned posterior continuous tear circular capsulorrhexis. Success rates depend on age of patient, cause of cataract and pre-existing intraocular disease. The highest success rate occurred in eyes with traumatic cataracts.     

Ultrasonographic abnormalities in eyes with traumatic hyphema obscuring intraocular structures: 33 cases (1991–2002)

Objective: To examine ultrasonographic abnormalities in eyes with traumatic hyphema obscuring intraocular structures.
Design: Retrospective clinical study.
Setting: The ophthalmology services of a private practice and university veterinary teaching hospital.
Animals: Twenty-two dogs, 6 cats, 3 horses, and 2 birds.
Measurements and main results: Medical records were reviewed for signalment, history, ophthalmic examination, ultrasonographic findings, treatment, and outcome in all patients that presented to the ophthalmology service with trauma-induced hyphema obscuring intraocular structures. Thirty-three patients were included and there were 35 affected eyes (17 left and 18 right). Abnormalities noted on ophthalmic examination included hyphema obscuring intraocular details beyond the iris (100%), corneal laceration (23%), iris prolapse (23%), fibrin clotting within the anterior chamber (17%), and subconjunctival and periocular bruising (17%). Ocular ultrasonography revealed the presence of either vitreous hemorrhage or a retinal detachment in 32 of 35 eyes (91%) with traumatic hyphema. Of the remaining 3 eyes, ocular ultrasonography revealed a lens luxation with posterior eye wall rupture in 1 eye and collapsed globes in the other 2 eyes. Twelve eyes were enucleated and 23 were treated medically. Ten of the medically treated eyes were lost to follow-up. Blindness was noted in all the affected eyes upon their final discharge and recheck examination.
Conclusions: Ocular ultrasonography revealed vitreous hemorrhage or a retinal detachment in 32 eyes (91%) with traumatic hyphema. Blindness was noted on the last available examination of every eye. The prognosis for vision in an eye with traumatic hyphema obscuring intraocular detail is poor.     

Cataracts are not associated with retinal detachment in the Bichon Frise in the UK--a retrospective study of preoperative findings and outcomes in 40 eyes

Objective The aim of this study was to evaluate whether the Bichon Frise population in the UK is at the same risk of developing retinal detachment in association with cataract formation and following phacoemulsification as described in reports from the USA. Procedures The medical records of Bichon Frises which were presented for cataract assessment and of those which were treated with phacoemulsification at Willows Referral Service between 1997 and 2009 were reviewed. Results Forty eyes (26 dogs) with unilateral or bilateral cataracts were included in the study. There was no evidence of retinal detachment associated with the cataracts at initial presentation. Phacoemulsification was performed on 34 eyes (20 dogs). Clinically evident lens‐induced uveitis was treated preoperatively in 17/34 eyes. Artificial lens implantation was carried out in 30/34 eyes; automated anterior vitrectomy was performed in 7/34 eyes. The mean follow‐up time was 16.6 months (range 1.5–73 months). At the last re‐examination, 31/34 eyes (91.2%) were visual. Three eyes (8.8%) were blind – two (in the same dog) because of presumptive bilateral optic nerve disease and one because of uveitis and secondary glaucoma. There was no evidence of retinal detachment following phacoemulsification in any of the 34 eyes. Conclusion This study suggests that the Bichon Frise population in the UK does not appear to have a predisposition for retinal detachment in association with cataract formation or following cataract surgery. Prophylactic random transscleral laser retinopexy or transscleral cryopexy cannot therefore be routinely recommended for Bichon Frises with cataracts in the UK.     

Microbial contamination of the anterior chamber during cataract phacoemulsification and intraocular lens implantation in dogs

The objective of this study was to determine the frequency of intraoperative contamination of the anterior chamber with viable microorganisms during cataract phacoemulsification and intraocular lens implantation, and to evaluate the relationship of contaminant microorganisms to patients' extraocular and nasal cavity floras. Also, the impact of various aspects of the patient history and phacoemulsification procedure on the incidence of positive postoperative anterior chamber cultures was investigated. Twenty-two eyes from 13 dogs presented for elective cataract phacoemulsification and intraocular lens implantation were studied. Preoperatively, microbiologic samples of the conjunctiva, eyelid margins, nares, and rostral nasal cavity were collected. Postoperatively, anterior chamber fluid was aspirated. Samples were submitted for aerobic/anaerobic bacteriologic culture and antimicrobial susceptibility, Mycoplasma culture, and fungal culture. Anterior chamber aspirates collected at the conclusion of surgery were culture positive for at least one organism in 22.7% of eyes. Three aerobic bacteria and three fungi were isolated from the anterior chamber aspirates. Two fungi and one bacterium isolated from the anterior chamber were typed identically, and the bacterium had a similar antibiogram to organisms recovered from the patient's conjunctiva and eyelid margin. No statistically significant difference in contamination frequency was found for the investigated patient and surgical variables. We conclude that intraoperative contamination of the anterior chamber with viable bacterial and fungal organisms is a common occurrence in canine patients undergoing cataract phacoemulsification and intraocular lens implantation, and the external ocular flora is a likely source of some of these contaminating microorganisms. This contamination is independent of the patient and surgical variables investigated.     

Keratometry, biometry and prediction of intraocular lens power in the equine eye

OBJECTIVE: To determine ocular dimensions (A- and B-scan ultrasound) and corneal curvature (radius of corneal diameter determined in B-scan ultrasound) in the equine eye and to calculate the appropriate dioptric power for a posterior chamber intraocular lens (IOL) necessary to achieve emmetropia in the eyes of horses undergoing lens extraction. ANIMALS: Fourteen clinically normal adult horses of various breeds. Additionally, for comparison, one American Miniature colt foal, and one 2.5-year-old Shire gelding were examined. PROCEDURE: B-scan ultrasound was performed on one eye from each horse. One eye from both the Shire and the American Miniature were examined for comparison. Data from ultrasound (globe measurements and corneal curvature), and the estimated postoperative IOL positions were entered into theoretical IOL formulas (Binkhorst and Retzlaff theoretical formulas) in order to calculate the predicted IOL strength required to achieve emmetropia after lens extraction in horses. Results: Mean axial length of globes was 39.23 mm +/- 1.26 mm, mean preoperative anterior chamber depth (ACD) was 5.63 +/- 0.86 mm, and mean lens thickness was 11.75 +/- 0.80 mm. Predicted postoperative ACD (PACD) was calculated as the ACD plus 50% of the lens thickness. Additionally, PACD 2 mm anterior and 2 mm posterior to the center of the lens were calculated in order to evaluate the effect of IOL position on its required refractive power. Required IOL strength calculated, using the three values for the predicted postoperative ACD, was 29.91 D +/- 2.50, 29 D +/- 2.52 (center of lens); 27.13 D +/- 2.27, 26.33 D +/- 2.20 (2 mm anterior to center of lens); and 33.18 D +/- 2.78, 32.24 D +/- 2.68 (2 mm posterior to center of lens) with the Binkhorst and Retzlaff theoretical formulas, respectively. CONCLUSIONS: An IOL of substantially lower diopter strength than that needed in either dogs or cats is required to achieve emmetropia after lens extraction in adult horses. IOL strength of approximately 30 D, depending on where the IOL ultimately comes to rest, will probably be required.     

Implantation of a foldable intraocular lens in dogs

A 1-piece, tripod-shaped, acrylic intraocular lens was implanted in the posterior chamber after phacoemulsification to remove cataracts in 20 eyes of 16 dogs. Biomicroscopy and intraocular pressure measurements were performed at 1, 8, 30, and 90 days after surgery; retinoscopy was performed at day 30. Complications were not encountered during implantation of the lens. All dogs had mild ocular inflammation characterized predominantly by aqueous flare and mild corneal edema at day 1, which resolved completely by day 8; 3 eyes had mild hyphema at day 1, which resolved by day 8. Three eyes developed fibrin in the anterior chamber, which resolved by day 30. Two eyes developed distorted pupils caused by adherence of vitreous humor or fibrin to the incision site. Postoperative intraocular pressure ranged from 7 to 21 mm Hg. Implantation resulted in 9 emmotropic eyes, 5 myopic eyes, and 6 hyperopic eyes. Maintenance of central lens position was excellent in 19 eyes; in 1 eyes, a disclocated superior haptic at day 2 was easily repositioned.     

Cataracts in Labrador Retriever and Jack Russell Terrier From the United Kingdom: A Two-Year Retrospective Study

Cataracts are among the most common ocular diseases, and are a leading cause of vision loss in humans and dogs. Jack Russell Terriers (JRT) and Labrador Retrievers (LR) are among the most popular canine breeds in the United Kingdom, and also among the most affected by cataracts.This study aimed to analyze the clinical features and the surgical outcome of cataracts in JRT and LR in an ophthalmologic reference Veterinary Hospital in the United Kingdom. For that purpose, medical records from JRT and LR diagnosed with cataracts between January 2015 and December 2016 were retrospectively evaluated. Data related to identification, clinical history, preoperative features, and surgical outcomes were analyzed.Forty-four dogs (81 eyes), including 26 JRT and 18 LR, were enrolled in the study. Mean ages were 10.2 ± 3.2 years in JRT and 8.5 ± 3.7 years in LR. Twenty-eight (63.6%) were females and 16 (36.4%) were males. Most dogs (84.1%) presented with bilateral cataracts. Nuclear and cortical cataracts were the most prevalent type in both breeds (JRT: n?=?30, 61.2%; LR: n?=?16, 50.0%), although subcapsular cataracts were also frequent in LR (n?=?10, 31.3%). Significant differences in cataract location within the lens were detected between the two breeds (P?=?.002).Senile in JRT (n?=?7) and genetic in LR (n?=?7) were the most common etiologies. Concomitant ocular lesions were more frequent in dogs presented with cataracts in advanced stages, and included lens (n?=?18; JRT: n?=?15; LR: n?=?3) and retinal alterations (n?=?8; JRT: n?=?2; LR: n?=?6), and glaucoma (n?=?6; JRT: n?=?5; LR: n?=?1). Thirty-three animals (75.0%, 51 eyes) were submitted to phacoemulsification with intraocular lens placement. Of these, 28 eyes (54.9%; JRT: n?=?21; LR: n?=?7) were visual, 19 eyes (37.3%; JRT: n?=?11; LR: n?=?8) presented impaired vision and four eyes (7.8%; JRT: n?=?0; LR: n?=?4) were blind at last clinical record. Postoperative complications were detected in 11 eyes (21.6%), and were more frequent in dogs presented with cataracts in advanced stages.These results and the multifactorial nature of cataracts call for further studies to identify and characterize the variables in a broader assessment, including other breeds and influencing factors.     

The effect of a topical antioxidant formulation including N-acetyl carnosine on canine cataract: a preliminary study

OBJECTIVE: To determine the efficacy of a topical antioxidant formulation including N-acetyl carnosine in the treatment of canine cataract in a preliminary nonplacebo, controlled, unmasked study. ANIMALS STUDIED: Thirty dogs of varying breeds and ages with a spectrum of lens opacities ranging from nuclear sclerosis to total mature cataract. METHODS: Dogs were treated three times daily with topical 2% N-acetyl carnosine in a buffered vehicle containing the antioxidants glutathione, cysteine ascorbate, L-taurine and riboflavin (Ocluvet, Practivet, Phoenix, AZ, USA). Dogs were examined prior to treatment and at 2, 4 and 8 weeks during treatment, by direct and indirect ophthalmoscopy and slit-lamp biomicroscopy after pharmacologic pupil dilation. Photographic documentation of lens opacity was achieved by retroillumination photography, with three photographs taken at each examination time-point. A lens opacification index (LOI), determined by integration of the grayscale level of each pixel across the image, was evaluated by computerized image analysis of digitized images. Alteration in mean LOI was determined for each animal, having normalized the initial LOI. RESULTS: Fifty-eight eyes of 30 dogs were evaluated, 22 with mature cataract, 13 with immature cataract, 9 with cataract associated with other intraocular disease such as uveitis and 14 with nuclear sclerosis alone. One dog was unilaterally anophthalmic after previous enucleation and one had a phthytic eye after previous uveitis-induced glaucoma. Image analysis showed a reduction in mean LOI in all cataract groups (mean resolution in opacity of 2.3 +/- 0.33% for all cataracts), although this was only statistically significant in those eyes with immature cataract (mean resolution of opacity 4.5 +/- 0.33%) or nuclear sclerosis (mean decrease in opacity 5 +/- 0.37%). Reduction in lens opacity was seen in eyes with mature cataract (0.5 +/- 0.4%) and in miscellaneous cataract associated with intraocular inflammation (1.3 +/- 0.4%), but these changes were not statistically significant. Owner evaluation of visual capability, however, suggested improvement in vision in 80% of cases by the end of the study. CONCLUSIONS: This study demonstrates some marginal reduction in lens opacification in a substantial number of cases of canine cataract with the use of a topical nutritional antioxidant formulation including N-acetyl carnosine. Lens opacification was improved with treatment in eyes with immature cataract or nuclear sclerosis while in eyes with mature cataract or cataract with associated intraocular inflammatory pathology less reduction was seen.