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

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.

Comparison of the outcomes of phacoemulsification versus topical medication alone in canine diabetic cataracts: a retrospective study

BACKGROUND

Long-term comparisons of phacoemulsification with topical medication are limited in canine diabetic cataracts.

OBJECTIVES

To compare outcomes of eyes submitted to phacoemulsification with those of topical medication for canine diabetic cataracts and identify risk factors for complications.

METHODS

Through medical records review, 150 eyes (76 dogs) with diabetic cataracts were included; 58 eyes (31 dogs) underwent phacoemulsification (phaco-group) and 92 eyes (48 dogs) received ophthalmic solution alone (medication-group). The medication-group was divided into owner-led and vet-led groups depending on who elected not to perform surgery. Comparisons involved time-to-complications, vision, and the number and type of ophthalmic solutions administered. The association between complications and pretreatment clinical findings was investigated.

RESULTS

No difference was found in complication risk between the phaco and owner-led medication groups. Conversely, the vet-led medication-group had a higher complication risk than the other groups. At the last follow-up, 94.8% of the phaco-group had vision, whereas 7.6% of the medication-group restored some visual axis. Poor glycemic control in the medication-group and younger age in the phaco-group increased complication risk. At 1-year post-treatment, the average number of ophthalmic solutions administered was 1.7 and 2.6 in the phaco and medication groups, respectively. The medication-group used anti-inflammatories the most throughout the follow-up, whereas the phaco-group used anti-inflammatories the most until 1-year post-treatment and lacrimostimulants at 1.5-year post-treatment.

CONCLUSIONS

For canine diabetic cataracts, phacoemulsification is recommended because it is superior to topical management alone in terms of maintaining vision and reducing the number of ophthalmic solutions required in the long term.

Prevalence and outcome of lens capsule disruption IN routine canine cataract surgery: A retrospective study of 520 eyes (2012-2019)

OBJECTIVE

To investigate the prevalence and surgical outcome of lens capsule disruption (LCD) in dogs undergoing cataract removal.

ANIMALS STUDIED

Medical records of 924 eyes undergoing phacoemulsification were analyzed retrospectively.

PROCEDURES

Routine cataract surgeries with or without LCD were included. Any LCD other than routine anterior capsulorhexis was defined as LCD and classified according to location and etiology. Odds ratios (OR) were calculated for maintaining vision, implantation of an artificial intraocular lens (IOL), and enucleation.

RESULTS

In total, 520 eyes were included. A LCD occurred in 145 eyes (27.8%; 145/520) and affected the posterior (85.5%; 124/145), anterior (6.2%; 9/145), and equatorial lens capsule (4.8%; 7/145) and at multiple locations (3.4%; 5/145). The etiology of the LCD was spontaneous preoperative in 41 eyes (28.3%; 41/145), accidental intraoperative in 57 eyes (39.3%; 57/145), and planned in 47 eyes (32.4%; 47/145). Disruption did not increase the odds of enucleation (OR = 1.48, 95% confidence interval [CI] 0.56-3.67; p = .36). The presence of LCD significantly increased the risk of losing vision 1 year post-operatively (OR = 8.17, 95% CI 1.41-84.93; p = .007) associated with retinal detachment. However, this was not present at 2 years follow-up or in PCCC cases at any time point. An IOL was implanted in 108 eyes (108/145; 75.2%) with LCD and in 45/47 (95.7%) eyes with a PCCC.

CONCLUSION

Increased surgeon awareness of possible intraoperative, accidental LCDs is important, as LCDs were relatively common and associated with increased odds for vision loss after 1 year in the present study. A prospective study investigating the causes of intraoperative, accidental LCD is warranted.

The clinical outcomes of 33 canine eyes following the novel sulcus fixation technique of an injectable acrylic lens through a 3-mm corneal incision

PURPOSE

This retrospective study introduces and evaluates transscleral fixation using a horizontal mattress suture of a conventional injectable acrylic intraocular lens (IOL) inserted through a 3-mm corneal incision in dogs.

MATERIALS AND METHODS

This technique was applied to four groups: lens subluxation (group SL, n = 15), anterior or posterior lens luxation (group APLL, n = 9), lens capsule tear or rupture (group LCTR, n = 7), and dislocation of the lens capsule containing an IOL (group IOLD, n = 4).

RESULTS

Patients were followed up for an average of 366.7 days (range: 94-830 days) after the surgery. Each IOL was well-centered and the overall visual success rate was 74.3% (26/35). Retinal detachment (4/35) was the most common cause of blindness, followed by glaucoma (3/35), hyphema of unknown etiology (1/35), and severe uveitis accompanied by deep corneal ulcer (1/35).

CONCLUSION

This technique enables sulcus fixation of an IOL, inserted through a 3-mm corneal incision, which is less traumatic than conventional techniques, without the need for specifically designed IOL for sulcus fixation. In this series, this technique enabled to contribute to restore emmetropic vision in dogs.

Posterior lens capsule rupture in non-diabetic canine cataracts: Pre-operative, intra-operative, and post-operative findings

PURPOSE

To describe clinical features of non-diabetic canine cataracts with presumed pre-existing posterior capsule rupture (PLCR) and their surgical outcomes.

METHODS

Clinical records of 497 non-diabetic canines that underwent elective cataract surgery were reviewed. Twelve canines met the inclusion criteria indicative of PLCR pre-dating surgery.

RESULTS

The incidence of presumed pre-existing PLCR was 12/497 (2.4%). Cataracts included were unilateral in 10 out of 12 canines (83.3%) and bilateral in the remaining two (16.7%). Four eyes (28.6%) had clinically detectable pre-operative lens-induced uveitis. The mean age at cataract diagnosis for cases included was 6.6 years, and golden retrievers were the most common breed affected (28.6%). Phacoemulsification surgery was performed at a median time of 110 days (range 17-403 days) after presentation. Pre-existing PLCR was found intra-operatively as a large ellipse spanning the posterior capsule from equator to equator centrally in 12 eyes and peripherally in two eyes. The capsular defect in all eyes with PLCR incorporated a distinct "pseudo-capsule" preventing vitreal presentation and ruling out intraoperative surgeon rupture. Ten eyes (71.4%) received an intraocular lens implant (IOL), and 13 eyes (92.9%) maintained vision throughout a mean follow-up period of 12 months.

CONCLUSION

Posterior lens capsule rupture of blunt trauma origin and associated cataract formation, as reported in humans, may also be an infrequent but distinct cause of some cases of non-diabetic canine cataracts. Medical management of phacolytic uveitis and delayed phacoemulsification surgery may be beneficial by allowing time for "pseudo-capsule" development, increasing the likelihood of IOL placement and improved visual outcomes.

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.

Post-operative outcomes in canine eyes receiving a rhexis-fixated prosthetic intra-ocular lens: 30 cases (2014-2020)

OBJECTIVES

To report the outcomes following the insertion of a rhexis-fixated prosthetic intraocular lens (IOL) in dogs undergoing lens removal.

MATERIALS AND METHODS

The results are from 30 eyes of 28 dogs, undergoing lendectomy, in which the lens capsule could not accommodate a conventional prosthetic endo-capsular IOL. The reported cases had sustained either spontaneous or traumatic lens capsule rupture, or accidental intra-operative iatrogenic lens capsule disruption, or had required a planned, large, anterior or posterior continuous curvilinear capsulorhexis, all of which precluded insertion of a prosthetic IOL within the lens capsule. An acrylic IOL (XVET; Medicontur) was modified and positioned across the anterior and/or posterior capsulorhexes.

RESULTS

Other than haptic luxation in three cases, no complications were seen that were directly attributable to the rhexis-fixated lens. Over a follow-up period from three to 76 months (mean 20.7 months) 26/30 eyes remained visual. Blindness developed in three eyes due to retinal detachment and one eye was enucleated due to regrowth of a ciliary body adenoma.

CLINICAL SIGNIFICANCE

Rhexis fixation provided an alternative method to implant a prosthetic IOL when the lens capsule was unable to accommodate a conventional endo-capsular IOL.

Bilateral cataract surgery in a Japanese macaque (Macaca fuscata): A case report

A 7.5-year-old intact male Japanese macaque was presented for evaluation of vision loss. After a complete ophthalmic examination, the patient was diagnosed with hypermature cataract in both eyes. After the cataract surgery, it was able to locate food and walk in a straight line.

Effect of topical administration of 0.1% diclofenac sodium ophthalmic solution at four frequencies on intraocular pressure in healthy Beagles

OBJECTIVE

To evaluate effects of topical ophthalmic administration of diclofenac on intraocular pressure (IOP) when applied at 4 frequencies to eyes of Beagles.

ANIMALS

8 ophthalmologically normal Beagles.

PROCEDURES

The study involved four 5-day experimental periods each separated by a 16-day washout period. During each period, 1 drop of 0.1% diclofenac sodium ophthalmic solution was administered to the right eye at 4 treatment frequencies (1, 2, 3, or 4 times/d); 1 drop of eyewash was administered to the left eye as a control treatment. A complete ophthalmic examination was performed on days 0 (day before first treatment) and 5 of each experimental period. Gonioscopy was performed on day 0 of the first period. The IOPs were measured at 7 am and 7 pm on days 1 through 5.

RESULTS

No abnormalities were detected during neuro-ophthalmic and ophthalmic examinations on day 0 of each experimental period. No adverse reactions to administration of diclofenac or eyewash were observed at any time point. No abnormalities were detected during ophthalmic examinations performed on day 5, and IOPs remained < 25 mm Hg in all 4 periods. No significant differences were identified between the treated and control eyes or among the 4 treatment frequencies.

CONCLUSIONS AND CLINICAL RELEVANCE

Topical ophthalmic administration of diclofenac up to 4 times/d in dogs with no ophthalmic abnormalities did not significantly increase the IOP. Additional research is needed to evaluate the effect of topical ophthalmic administration of diclofenac on IOP in dogs with anterior uveitis.

Retrospective review of cataract surgery outcomes in Miniature Schnauzers

OBJECTIVE

Miniature Schnauzers commonly develop both inherited and diabetic cataracts. Miniature Schnauzers also often present with concurrent metabolic disease at the time of cataract surgery. The purpose of this study was to evaluate cataract surgery outcomes in Miniature Schnauzers.

MATERIALS AND METHODS

The Eye Care for Animals electronic medical record database (2012-2018) was searched for "phacoemulsification" and "Miniature Schnauzer." A minimum follow-up time of 1 year was required for inclusion in the study. Clinical history, pre- and postoperative bloodwork, postoperative treatments, and visual outcomes were reviewed in all cases.

RESULTS

Cataract surgery was performed on 67 patients and 124 eyes. 93.5% (116/124) of operated eyes were visual 1 year following cataract surgery. At the time of surgery, 79.1% were diabetic, 64.2% had hypercholesterolemia, 55.2% had hypertriglyceridemia, 16.4% had hyperadrenocorticism, and 9% had a history of pancreatitis. Dorzolamide was used postoperatively in 61.2% of patients, and its use was significantly associated with postoperative cholesterol levels above reference range. Lipemic aqueous occurred in 13.4% of patients.

CONCLUSIONS

Miniature Schnauzers presenting for cataract surgery are frequently affected by metabolic diseases and dyslipidemia; however, cataract surgery outcomes were not significantly affected during the study period. Dietary management, omega-3 fatty acid supplementation, and oral fibrates may reduce the incidence of lipemic aqueous in Miniature Schnauzers.

Effect of Insulin and Fasting Regimen on Blood Glucose Concentrations of Diabetic Dogs During Phacoemulsification

This study aimed to compare four protocols for preanesthetic insulin administration and fasting time with respect to the variation of intraoperative blood glucose (BG) concentrations versus preanesthetic values (baseline). The patient records of dogs undergoing cataract surgery were included. Data on anesthetic protocols, comorbidities, and intraoperative complications (hyper- and hypoglycemia, hypotension, hypothermia, and bradycardia) were analyzed. The insulin/fasting protocols included (A) 12 hr fasting and half insulin dose, (B) 6 hr fasting and half insulin dose, (C) 12 hr fasting and full insulin dose, and (D) 12 hr fasting and no insulin. Forty-eight dogs were included (14 in A, 10 in B, 13 in C, and 11 in D). Protocol D resulted in a significant increase of intraoperative BG concentrations compared with baseline (P = .001), whereas in the remaining groups, the baseline BG did not differ from intraoperative values. There were no statistically significant associations between the treatment group and the occurrence of intraoperative complications or the presence of diagnosed comorbidities. In conclusion, different insulin and fasting regimen protocols may be used for diabetic patients with no apparent benefit or risk from one protocol versus another. The use of insulin before surgery results in lesser increase of BG intraoperatively as compared with preanesthetic values. However, whether this should be interpreted as better perioperative control of glycemia remains debatable.

Progression and complications of canine cataracts for different stages of development and aetiologies

OBJECTIVES

To evaluate progression and complications of various cataract aetiologies and stages of development.

MATERIALS AND METHODS

In all, 447 eyes of 250 dogs with cataracts were monitored between 2012 and 2015. Breed, gender, age, vision, types of cataract, stage of cataract development (incipient, immature, mature and hypermature), complications of cataracts, ocular ultrasonography and electroretinography findings were recorded. Re-examinations were performed after a minimum of 1, 6 and 12 months. A relative rate of progression within 1 month was determined and progression was categorised as stationary, slow, moderate or rapid.

RESULTS

Overall, 44∙7% cataracts progressed and 55∙3% remained stationary. Incipient, immature, mature and hypermature cataracts progressed in 34∙1, 72∙7, 66∙7 and 44∙6% of cases, respectively. Hereditary, congenital, diabetic, contusive trauma-related, perforating trauma-related, radiation-related, senile cataracts and cataracts secondary to concurrent ocular diseases progressed in 47∙1, 66∙7, 66∙7, 50, 44∙4, 0, 29∙9 and 48∙9% of cases, respectively. Rapid progression was identified in 13∙3% of diabetic and 4∙3% of hereditary cataracts. Complications were diagnosed in 43∙5% and occurred at any stage but more frequently the further the cataract had developed. Lens-induced uveitis was the most common complication. Diabetic, traumatic, secondary and hereditary cataracts were associated with more complications than senile cataracts.

CLINICAL SIGNIFICANCE

Stage of development and cataract aetiology are associated with different rates of progression and complications.

Canine Diabetes Mellitus Associated Ocular Disease

Diabetes mellitus (DM) is a commonly encountered disease in companion animal veterinary practice. Ocular complications in dogs with DM are thought to be common but there are no reports of the overall incidence of DM-associated ocular disease. Some complications, such as cataracts and ocular surface disease, can lead to vision loss and significant morbidity among DM patients, therefore early recognition and intervention are essential for successful outcomes. The purpose of this article is to provide a review of several currently known or suspected ocular diseases associated with DM.

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.

[Cataracts in dogs--overview and guideline for decision making in treatment]

Cataract is the leading cause of impaired vision and vision loss in dogs. Because of the considerable progress in cataract surgery in recent decades, lens opacities can now be operated on with very good short-term success (90-95%), taking into account that proper patient selection is essential to maximize the probability of a successful surgical outcome. Following a description of anatomical and physiological lens characteristics, the etiology and complications of untreated cataracts are discussed. Furthermore, specific criteria for patient selection are addressed while delineating essential steps of the examination. This article aims to aid decision making in cataract therapy on the basis of diagnostic guidance and to facilitate the selection of an appropriate point of time for surgery.

A comparison of anesthetic complications between diabetic and nondiabetic dogs undergoing phacoemulsification cataract surgery: a retrospective study

OBJECTIVE

To compare the incidence of anesthetic complications in diabetic and nondiabetic dogs undergoing general anesthesia and phacoemulsification cataract surgery.

PROCEDURE

The medical and anesthetic records of all dogs undergoing phacoemulsification cataract surgery at Davies Veterinary Specialists between 2005 and 2008 were reviewed. Anesthetic records were evaluated by an ECVAA Diplomate. Dogs for which records were incomplete were excluded. The anesthetic technique, including all drugs administered in the perioperative period, was recorded. The anesthetic complications investigated included hypotension (MAP (mmHg): >or=55 none/mild; <or=54 moderate/severe), bradycardia (<60 bpm associated with hypotension) and hypothermia (esophageal temperature <36.7 degrees C). Where hypotension was present, the method of and response to treatment was recorded. The incidence of severe hyperglycemia (blood glucose >13.75 mmol/L (250 mg/dL)) in the diabetic group was also assessed.

RESULTS

66 diabetic and 64 nondiabetic dogs were included in the study. Diabetic dogs were more likely to develop moderate and severe intraoperative hypotension than nondiabetic dogs. Forty-four percent of diabetic dogs had at least one episode of severe hyperglycemia whilst anesthetized.

CONCLUSIONS

Diabetic dogs undergoing phacoemulsification are more likely to suffer the anesthetic complications of moderate and severe hypotension than nondiabetic dogs. The increased incidence and severity of hypotension in diabetic dogs may be explained by hypovolemia secondary to hyperglycemia and resultant osmotic diuresis.

A and B mode ultrasonography in preoperative evaluation of lens and posterior segment of dogs eyes with cataract

Ultrasonography of the lens and posterior segment is an indispensable step in the preoperative evaluation of dogs with cataracts, since ophthalmoscopy is not feasible when there is opacification of the lens. This study evaluated the echographic conditions of cataractous lens and fundus of the eye in dogs affected by cataracts. The study was conducted in 30 dogs (56 eyes), 10 males and 20 females, with different types of cataracts at different stages of development. Echography in A and B modes, simultaneously, was carried out for the examination of the lens and posterior segment. The examinations revealed anterior cortical, posterior cortical and nuclear cataract in 12 eyes (21.4%), anterior cortical, posterior cortical, nuclear and posterior capsular in 23 eyes (41%), anterior cortical, posterior cortical and posterior capsular cataract in one eye (1.7%), anterior cortical and nuclear cataract in one eye (1.7%), anterior cortical, nuclear and posterior capsular cataract in five eyes (8.9%), and anterior cortical cataract in seven eyes (12.5%). Abnormal ultrasonographic alterations were observed in the posterior segment in 26 eyes evaluated (46.4%). Vitreal degeneration was detected in 12 eyes (21.4%), images of vitreal exudate or hemorrhage in seven eyes (12.5%), persistence of hyaloid artery in four eyes (7.1%) and lens subluxation in three eyes (5.3%). The results obtained reiterate the importance of ultrasonography in canine patients presented for cataract surgery given that alterations of the posterior segment are difficult to identify in a clinical examination when the lens is opacified.

Update on veterinary cataract surgery

PURPOSE OF REVIEW

The purpose of this review is not to specifically discuss the techniques of veterinary cataract surgery, but rather to emphasize some of the differences between the veterinary and human cataract patients, procedures and outcomes.

RECENT FINDINGS

In general, veterinary cataract surgery has more similarities than differences when compared to its human counterpart. This is especially true when comparing pediatric cataract patients. Veterinary cataract surgery has changed dramatically in recent years with regards to surgical technique, ocular pharmacology, viscoelastic devices, phacoemulsification, and the most recent advancement, intraocular lens implantation for dogs, cats, and horses.

SUMMARY

It is hoped that the exchange of information between the human and veterinary specialties can be of benefit to both groups as we all work to improve outcomes and resolve complications.

Cataracts: when to refer

Unique stages of cataract development have been characterized in both human and animal lenses. These lens opacities impair visual acuity and are associated with inflammation. Total lens removal is typically followed by implantation of an artificial intraocular lens to restore vision. The success of this procedure is mainly dependent on the developmental stage of the cataract to be removed. This article reviews cataract development and provides the clinician with cataract referral criteria.

A modified ab externo approach for suture fixation of an intraocular lens implant in the dog

The goals of canine cataract and lens instability surgery should be to ensure a small incision, minimal tissue trauma, shortened surgical time, maintenance of the anterior chamber, and restoration of emmetropia through the use of a stable intraocular lens specifically designed for the canine eye. While this is usually the case with routine phacoemulsification and in-the-bag intraocular lens implantation, it is often not the case with lens instability, lens luxation or large posterior capsular ruptures. In such cases the incisions are often larger, surgical time and tissue trauma are excessive, and the patient is often left aphakic. The goal of this paper is to present a modified ab externo technique designed to allow removal of the lens and placement of a ciliary sulcus sutured IOL through a small incision, with minimal trauma and shortened surgical time. Use of this technique may allow more canine patients to be emmetropic postoperatively. In addition, the ease of this procedure may encourage earlier removal of an unstable lens and decrease the risk of secondary glaucoma and retinal detachment that occur in association with lens luxation.