Gonioscopic iridocorneal angle morphology and incidence of postoperative ocular hypertension and glaucoma in dogs following cataract surgery

Efficacy of perioperative 2% dorzolamide ophthalmic solution for reduction of postoperative ocular hypertension in dogs following routine phacoemulsification surgery: A prospective clinical trial

OBJECTIVE

To evaluate the efficacy of 2% dorzolamide ophthalmic solution for reduction of postoperative ocular hypertension (POH) following routine phacoemulsification surgery in dogs.

ANIMALS STUDIED

Thirty one dogs (53 eyes) with naturally occurring cataracts undergoing routine phacoemulsification surgery.

PROCEDURE(S)

A prospective, double-masked, randomized, placebo-controlled study design was utilized. Dogs received 2% dorzolamide ophthalmic solution or saline 1 h prior to surgery then three times daily for 21 days postoperatively in the operated eye(s). Intraocular pressure (IOP) was recorded 1 h prior to surgery and 3 h, 7 h, 22 h, 1 week and 3 weeks postoperatively. Statistical analyses were performed using chi-squared and Mann-Whitney U test with a significance level of p < .05.

RESULTS

Postoperative ocular hypertension (IOP ≥25 mmHg, <24 h after surgery) occurred in 28/53 (52.8%) eyes. There was significant reduction in the incidence of POH for eyes receiving dorzolamide (10/26 (38.4%) eyes) versus eyes receiving placebo (18/27 (66.7%) eyes) (p = .0384). Animals were followed for a median of 163 days after surgery. Thirty-seven (37/53 (69.8%)) eyes were visual at final examination and 3/53 (5.7%) globes were enucleated postoperatively. At last follow-up, there was no difference in visual status (p = .9280), need for topical IOP lowering medication (p = .8319) or incidence of glaucoma (p = .5880) based on treatment group.

CONCLUSIONS

Perioperative administration of topical 2% dorzolamide reduced the incidence of POH after phacoemulsification in the dogs studied. However, this was not associated with differences in visual outcome, incidence of glaucoma or need for IOP-lowering medications.

Vision outcomes in dogs with primary glaucoma surgically treated with lensectomy and endolaser cyclophotocoagulation after an Ahmed valve gonioimplantation failure

OBJECTIVE

The aim of this study was to retrospectively evaluate vision outcomes of dogs with primary angle closure glaucoma (PACG) that underwent Ahmed valve gonioimplantation (AVG) followed by lensectomy and endolaser cyclophotocoagulation (ECP) with or without bleb resection after AVG failure.

PROCEDURE

Medical records from 2008 to April 2022 were reviewed. All patients selected had an AVG performed first. Following valve failure, lensectomy-ECP was performed in addition to bleb resection as indicated. Additional ECP and AVG replacement surgeries were performed as deemed medically necessary. Main outcomes evaluated included vision preservation, average IOP reduction, and the number of glaucoma medications (both oral and topical) at 6, 12, 24, and 36 months.

RESULTS

Fourteen eyes from 13 patients were included in the study. Females were predominant (n = 9) compared with males (n = 4). Mean age at initial glaucoma diagnosis was 6.82 years. Following AVG and lensectomy-ECP, vision was preserved in 93%, 84%, 60%, and 48% of eyes at 1, 2, 3, and 4 years respectively. Following lensectomy-ECP, there was a significant reduction in mean IOP of 9.64 mmHg (p = .015) and 9.71 mmHg (p = .016) at 2 and 6 months, respectively. There was a reduction in mean IOP of 2.45, 7.25, and 12.25 mmHg at 12, 24, and 36 months, respectively, which was not statistically significant. There was a significant decrease in the number of glaucoma medications at all evaluated time points except 24 months.

CONCLUSIONS

Combined AVG and lensectomy-ECP is successful in maintaining vision long term as well as decreasing IOP, and the number of glaucoma medications administered.

Quantitative analysis of iridocorneal angle and ciliary cleft structures in canine eyes using ultrasound biomicroscopy

Introduction

This study aimed to examine the relationship between the relative opening of the ICA (RO-ICA) and the structure of the ciliary cleft (CC) using Ultrasound Biomicroscopy (UBM).

Materials and methods

Clinical data from 31 eyes of 17 dogs at the Veterinary Teaching Hospital of Chungbuk National University, Korea, were analyzed. RO-ICA was categorized as "Slightly Narrow", "Narrow", "Open", and "Wide Open", with eyes further grouped into "Narrow" (including Slightly Narrow and Narrow) and "Open" (including Open and Wide Open) for analysis. Statistical methods, including linear regression and average comparisons between groups, were employed to explore correlations between RO-ICA and parameters such as ICA, CC width (CCW), CC length (CCL), and CC area (CCA).

Results

The distribution showed "Narrow" (3 eyes, 9.7%), "Slightly Narrow" (13 eyes, 41.9%), and "Open" (14 eyes, 45.2%) as the predominant categories. In the Open group, CCL and CCA were significantly larger compared to the Narrow group. A positive correlation was observed between RO-ICA and CCL, and CCA across all groups. Notably, in the Narrow group, RO-ICA demonstrated a particularly significant positive correlation with all assessed parameters, including ICA, CCW, CCL, and CCA. However, no significant correlation was observed between RO-ICA and the assessed parameters in the Open group. In conclusion, while a smaller RO-ICA generally correlates with a smaller CC, a larger RO-ICA does not guarantee a larger CC.

Conclusion

Additional UBM examinations are recommended for comprehensive evaluations, particularly in cases where gonioscopy indicates an open iridocorneal angle.

Training Veterinary Ophthalmology Residents on Cataract Surgery (Part A: Diplomate's Survey)

The purpose of this study was to explore the teaching methods used to train residents in cataract surgery at academic and private practice institutions. A descriptive survey was distributed online to 186 active supervising diplomates of the American Board of Veterinary Ophthalmologists (ABVO) listserv. The survey included items about various educational resources and techniques available to ophthalmology residents when performing cataract surgery. Thirty-seven (19.9%) supervising diplomates completed the survey. Most supervising diplomates (29, 78.4%) required supervised practice in the wet lab. Fourteen supervising diplomates (37.8%) provided mandatory cataract surgery lectures. Nine diplomates (24.3%) required their residents to attend a formal phacoemulsification wet lab course. There was no difference in the number of diplomates who allowed their residents to perform cataract surgery as the primary surgeon during their second year compared to any other year. Thirty-three surveyed diplomates supported the idea of creating an assessment tool to improve surgical competency. This article describes the current trends in veterinary ophthalmology residency education and provides support for the creation of an assessment tool to improve surgical competency. The goal is to stimulate future research on how educators can effectively train veterinary ophthalmology residents to improve surgical proficiency.

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.

Inter-device agreement between spectral domain optical coherence tomography, ultrasound biomicroscopy, and gonioscopy in evaluating the iridocorneal angle in normotensive dogs

BACKGROUND

There has not been a thoroughly reported study of the comparison between spectral domain-optical coherence tomography (SD-OCT) with both ultrasound biomicroscopy (UBM) and gonioscopy on the evaluation of the iridocorneal angle (ICA) in dogs.

OBJECTIVES

To investigate the diagnostic value of SD-OCT for the early detection of narrowing ICA by comparing and assessing inter-device agreement in anterior chamber angle (ACA) measurements obtained by SD-OCT and UBM, and ICA evaluations by gonioscopy.

METHODS

A total of 28 eyes from 28 client-owned dogs with normal intraocular pressure were included for examination. The ACA and angle opening distance (AOD) were measured from the SD-OCT and UBM images, and gonioscopy images were analyzed using the ICA grade and ZibWest angle index.

RESULTS

The mean ACA and AOD for SD-OCT were 28.31° ± 5.37° and 658.42 ± 219.90 µm, and for UBM, 28.34° ± 5.82° and 859.29 ± 221.80 µm, respectively. The mean difference in ACA between the average values of SD-OCT and UBM measurements was 0.03° with a 95% limit of agreement (LoA) span of 16.2°, indicating positive agreement; that in AOD was 200.85 µm with a 95% LoA span of 1,110.95 µm, indicating poor agreement. The Pearson correlation coefficient of the ACA of SD-OCT and ZibWest indices of gonioscopy was 0.624, indicating strong agreement; that of UBM and gonioscopy was 0.43, indicating moderate agreement.

CONCLUSIONS

SD-OCT is well tolerated by canine patients due to its non-contact method and might be an alternative option for early screening of ICA narrowing in clinical settings.

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.

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.

The association of topical flurbiprofen with the incidence of postoperative glaucoma after phacoemulsification in dogs

OBJECTIVE

To investigate the relationship between topical administration of flurbiprofen plus corticosteroids versus corticosteroids alone following phacoemulsification and the development of postoperative glaucoma in dogs.

ANIMAL STUDIED

Thirty-eight/eighty-three (45.8%) eyes were prescribed topical flurbiprofen plus corticosteroids immediately postop while 45/83 (54.2%) eyes received topical corticosteroids alone.

PROCEDURES

Logistic regression models were performed to analyze the relationship between topical flurbiprofen and development of glaucoma and to predict potential risk factors for postoperative glaucoma occurrence.

RESULTS

Eighty-three eyes (65 dogs) were included. The mean age at surgery was 8.2 years, with even gender distribution. Increasing age at the time of surgery significantly increased the probability of postoperative glaucoma occurrence (odds ratio [OR] = 1.344, 95% confidence interval [CI] 1.093-1.652; p = 0.005). Glaucoma occurred in 17/83 (20.5%) eyes; of these, 15/38 (39.5%) and 2/45 (4.4%) eyes were prescribed topical flurbiprofen plus corticosteroids and topical corticosteroids alone, respectively. Immediate postoperative use of topical flurbiprofen was significantly associated with an increased probability of postoperative glaucoma occurrence (OR = 19.183 [95% CI 3.367-109.286], p = 0.001).

CONCLUSIONS

Immediate postoperative use of topical flurbiprofen was a potential predisposing risk factor for the development of glaucoma following phacoemulsification. Restriction of postoperative use of topical flurbiprofen might decrease the possibility of postoperative glaucoma development in dogs.