Comparison of topically applied flurbiprofen or bromfenac ophthalmic solution on post-operative ocular hypertension in canine patients 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.

Topical Ocular Therapeutics in Small Animals

This article reviews the administration of common topical ophthalmic medications, in relation to factors influencing absorption including composition of topical ophthalmic preparations, and potential systemic effects. Commonly prescribed, commercially available topical ophthalmic medications are discussed with respect to pharmacology, their indications for use, and adverse effects. Knowledge of topical ocular pharmacokinetics is essential for the management of veterinary ophthalmic disease.

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.

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.

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

PURPOSE

To investigate the relationship between gonioscopic iridocorneal angle (ICA) morphology and the incidence of postoperative ocular hypertension (POH) and postoperative glaucoma in dogs undergoing cataract surgery.

ANIMALS STUDIED

Retrospective analysis of 138 eyes of 78 canine patients who underwent phacoemulsification at North Carolina State University from December 1, 2015 through April 30, 2017.

METHODS

Medical records of all phacoemulsification patients with preoperative RetCam gonioscopic images were reviewed for preoperative, intraoperative, and postoperative variables. Gonioscopic angle indices were calculated using a novel (ZibWest) angle grading system, and these indices were analyzed for outcome-related significance.

RESULTS

Increased surgeon experience was associated with increased probability of POH and vision loss. Higher average ZibWest Angle indices (ie, more open angles with less pectinate ligament dysplasia/ abnormality) were associated with a significantly decreased probability of medically unresponsive glaucoma. Increased patient age was significantly associated with an increased probability of both postoperative glaucoma and vision loss. Female dogs were significantly more likely to experience postoperative glaucoma compared to male dogs. Increased surgery time was significantly associated with increased probability of vision loss.

CONCLUSIONS

The ZibWest angle index may predict increased risk for developing medically unresponsive glaucoma with cataract surgery. Female sex, and increased patient age, surgical time, and surgeon experience were associated with increased postoperative morbidity.

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.

Treatment of canine postoperative ocular hypertension with combined latanoprost 0.005% and atropine 1% ophthalmic solutions

OBJECTIVE

To compare the effects of topical 0.005% latanoprost (L) vs combined 0.005% latanoprost and 1% atropine (LA) on control of postoperative ocular hypertension (POH), development of posterior synechiae formation, pupil size, and blindness after phacoemulsification surgery in dogs.

ANIMAL STUDIED

Dogs with postoperative ocular hypertension were included in the study: L-group, latanoprost (eight dogs, 14 eyes) and LA-group, latanoprost and atropine (nine dogs, 15 eyes).

PROCEDURES

Complete ophthalmic examinations including tonometry were performed at 1, 7, and 21 days following phacoemulsification.

RESULTS

No significant differences were found between the measured intraocular pressure (IOP) at days 1 and 7 postphacoemulsification surgery in the L-group and the LA-group (P = 0.26 [14.12 ± 1.76 mmHg vs 16.96 ± 1.68 mmHg] and P = 0.71 [15.45 ± 1.43 mmHg vs 16.20 ± 1.36 mmHg], respectively). No significant differences were found between pupil sizes at day 7 for the two groups (P = 0.25 [13.83% vs 24.77%]). No significant differences were found between odds of posterior synechiae formation at day 21 (P = 0.92) with a probability ± SE for L-group vs LA-group at 0.27 ± 0.14 vs 0.25 ± 0.13. No significant differences were found in odds of postoperative blindness between groups (P = 0.58) with a probability ± SE of 0.21 ± 0.11 vs 0.13 ± 0.09, respectively for L and LA.

CONCLUSIONS

Combined topical latanoprost and atropine in dogs maintains normal postoperative IOPs but does not seem to cause increased mydriasis compared to latanoprost alone.

Comparison of early posttreatment effects of two steroidal anti-inflammatory ophthalmic drugs on the ocular inflammatory response induced by paracentesis in healthy canine eyes

OBJECTIVE

We investigated the early posttreatment effects of two steroidal anti-inflammatory ophthalmic drugs on blood-aqueous barrier (BAB) breakdown by paracentesis in dogs.

ANIMAL STUDIES

We studied 21 healthy beagles with normal eyes.

PROCEDURES

Controlled anterior chamber paracentesis (0.5 mL) was performed in one eye of each dog. Control group dogs (n = 7) received no medication, whereas those in the treatment groups received a topical anti-inflammatory medication (difluprednate [DFBA] ophthalmic emulsion 0.05% [n = 7] or betamethasone [BMZ] sodium phosphate ophthalmic solution 0.1% [n = 7]) at 0, 15, 30, and 45 minutes after initial paracentesis in the paracentesed eyes. Secondary aqueous humor (AH) was collected 60 minutes after initial paracentesis. Protein and prostaglandin E₂ (PGE₂ ) concentrations in AH were determined using the bicinchoninic acid assay and commercially available immunoassay kit, respectively. All mean values in the three groups were compared using analysis of variance followed by Tukey's post hoc test.

RESULTS

Aqueous protein and PGE₂ concentrations were markedly increased at 60 minutes following paracentesis. Both concentrations in the secondary AH of the DFBA group were significantly lower than those of the control group; however, treatment with BMZ had no significant effects.

CONCLUSIONS

Early postparacentesis treatment with DFBA was more effective than that with BMZ for reducing aqueous protein and PGE₂ contents in dogs with paracentesis-induced BAB breakdown. DFBA may be an appropriate treatment during the early stage of anterior uveitis caused by intraocular surgery in dogs.

Contribution of prostanoid FP receptor and prostaglandins in transient inflammatory ocular hypertension

We explored the involvement of FP receptor and endogenous prostaglandins (PGs) in transient ocular hypertension (OH) induced by PGE2 or PGF2α in mouse eyes. PGE2 and PGF2α were topically applied to induce transient OH in Wild-type (WT) and FP-, EP1-, EP2-, and EP3-deficient (knockout [KO]) mice. To suppress endogenous PG production, the non-steroidal anti-inflammatory drug nepafenac was applied topically before treatment. PGE2 and PGF2α induced significant OH in the WT, FPKO, and EP1–3KO mice compared to the control 30 min after instillation, and the increase in IOP at 30 or 60 min after instillation in FPKO mice was significantly higher than that in the WT mice. The effects of PGF2α on the increase in IOP were significantly weaker than those of PGE2, especially in EP1KO and EP3KO mice. Transient OH induced by PGE2 and PGF2α was significantly attenuated by nepafenac treatment in FPKO mice. Transient OH was induced by PGE2 and PGF2α in WT, FPKO, and EP1–3KO mice, which was enhanced in FPKO mice. This OH was significantly diminished by nepafenac treatment in FPKO mice, suggesting that FP receptor may have an important naïve physiological role in the eye, and could regulate IOP elevation during PG-associated ocular inflammation.