Morphologic studies of uveoscleral outflow in normotensive and glaucomatous beagles with fluorescein-labeled dextran

Aqueous humor leaves the anterior chamber through 2 pathways: the trabecular meshwork of the iridocorneal angle and the unconventional uveoscleral route. In the latter route, aqueous humor leaves the anterior chamber, passes caudally through the trabecular meshwork and sclerociliary cleft to enter the supraciliary and suprachoroidal spaces. The fluid is absorbed by the choroidal and scleral circulation. Fluorescein-labeled dextran was slowly infused into the posterior chamber of healthy and glaucomatous Beagles for 30 minutes. The eyes were fixed in a mixture of 70% alcohol and formalin, placed in epoxy resin for histologic evaluation, and examined by fluorescent microscopy. Fluorescence was detected in the healthy dogs throughout the uveoscleral pathway. In the glaucomatous dogs, the uveoscleral outflow was decreased or completely absent.     

Aqueous outflow in the beagle: unconventional outflow, using different-sized microspheres

Normal drainage of aqueous humor from the anterior chamber of the canine eye occurred through the angular aqueous plexus and uveoscleral route. In order to understand more clearly, uveoscleral outflow with regard to larger sized tracer particles and the possible influence that varying intraocular pressure (IOP) may have on them, microspheres of 3 sizes, 0.5, 1.0, and 3.0 micron, were perfused at 3 different IOP (20, 50, and 75 mm of Hg) for 3 different times (30, 60, and 90 minutes). Presence of spheres was detected by light microscopy and scanning electron microscopy, and verified by transmission electron microscopy. By 30 minutes of perfusion, all 3 sphere sizes thoroughly infiltrated the anterior uveal trabecular meshwork. At normotensive pressure (20 mm of Hg), spheres of each size penetrated the outer anterior extension of the ciliary musculature and entered the supraciliary space. Only 0.5- and 1.0-micron spheres moved posteriorly into the suprachoridal space. At hypertensive pressures, movement of the tracer particles increased markedly toward the posterior uveal trabecular meshwork. However, 3.0- and 1.0-microns spheres did not enter the supraciliary space and suprachoroidal space, respectively. Spheres also entered the iris, mostly at its root. They remained comparably sparse at different perfusion times and IOP. The present study supported evidence for uveoscleral outflow (vs uveovortex) in the dog and indicated that passage of materials through this pathway may be influenced by IOP when these substances are within a critical size range.     

Unconventional aqueous humor outflow of microspheres perfused into the equine eye

Normal drainage of aqueous humor from the anterior chamber of the equine eye occurred through conventional and unconventional routes. To determine the degree of uveoscleral outflow in the pony, 1- and 3-microns (diam) microspheres were perfused through the anterior chamber for 60 and 90 minutes. Two eyes were treated with pilocarpine before perfusion of spheres to observe any effect on outflow. Presence of spheres was detected by scanning electron microscopy and verified by light microscopy. By 60 minutes of the perfusion, 1- and 3-microns spheres thoroughly infiltrated the anterior uveal trabecular meshwork. The 3-microns spheres were notably excluded from the corneoscleral trabecular meshwork, whereas the 1-micron spheres packed into the corneoscleral trabecular meshwork and mixed with the angular aqueous plexus and intrascleral plexus vessels. After 90 minutes, 1- and 3-microns spheres penetrated the prominent supraciliary space and mixed with the suprachoroidea of the midchoroid. The 1-micron spheres infiltrated tissues more extensively than did the 3-microns spheres, packing into the anterior meshwork and supraciliary space and also moving as far posterior as the suprachoroidea of the peripapillary retina. Spheres also entered the iris, mostly at the root. Several 3-microns spheres moved into the interstitial spaces around axon bundles and vessels in the iris. The 1-micron spheres packed into these spaces in the iris root and were observed in the lumens of iris vessels. Single 1-micron spheres were observed in the lumens of choroidal vessels posteriorly. The present study supported evidence for uveoscleral and uveovortex flow in the horse and indicated that it may be more extensive than that in other species investigated (ie, the dog).     

Effect of topical atropine on intraocular pressure and pupil diameter in the normal horse eye

The objective was to determine whether topically administered 1% atropine would alter intraocular pressure. The animals studied were four healthy adult horses. Intraocular pressure and pupil diameter were measured prior to and during a 2-day period of treatment with 1% atropine sulfate. No significant changes in intraocular pressure occurred as a result of the treatment with atropine. Pupil diameter increased significantly after atropine was applied. Available information on the outflow of aqueous humor from the horse eye suggests that atropine might reduce intraocular pressure in the horse by increasing uveoscleral outflow. This could prove beneficial in the treatment of equine glaucoma. We could not confirm a significant pressure-lowering effect of atropine. It is possible, however, that a longer treatment period may be required or that atropine may have a more profound effect on glaucomatous globes.     

Effect of hyaluronidase on aqueous outflow resistance in normotensive and glaucomatous eyes of dogs.

The anterior chambers in 16 dogs with normotensive eyes and 3 Beagles with glaucomatous eyes were treated with 0, 25, 50, or 100 IU of bovine testicular hyaluronidase. Aqueous outflow resistance was then determined by constant-pressure perfusion of 0.9% NaCl solution for 30 or 60 minutes. In normotensive eyes, 25, 50, or 100 IU of hyaluronidase significantly (P less than 0.02) increased the rate of constant-pressure perfusion compared with that of untreated eyes during 30- or 60-minute perfusions. Treatment of glaucomatous eyes with 25, 50, or 100 IU of hyaluronidase did not significantly increase the rate of constant-pressure perfusion over controls during a 30-minute perfusion. Bovine testicular hyaluronidase at all doses removed the staining of colloidal iron from the trabecular meshwork in normotensive eyes. In Beagles with glaucoma, the trabecular meshworks remained stained with colloidal iron when treated with the hyaluronidase, which suggested that some glycosaminoglycans were resistant to this enzyme's action.     

Intraocular pressure and glaucoma.

Aqueous humor is a transparent fluid that fills the anterior and posterior chambers, and the pupil, of the eye. It is produced in the ciliary processes, and exits the eye through two major pathways--the iridocorneal (conventional) outflow, and the uveoscleral (unconventional) outflow. Equilibrium between production and drainage of aqueous humor enables the body to maintain constant intraocular pressure (IOP). Disruption of aqueous outflow, usually through the conventional pathway, results in elevation of IOP. This elevation in IOP is a major risk factor in the pathogenesis of glaucoma, a group of diseases characterized by decreased retinal function and progressive optic nerve damage that may result in blindness. This article reviews the anatomy and physiology of aqueous dynamics in exotic species, the causes, clinical signs and diagnosis of glaucoma, and therapeutic approaches.     

Ascorbic acid levels of aqueous humor of dogs after experimental phacoemulsification

Phacoemulsification has been successfully employed in humans and animals for lens extraction. This ultrasonic extracapsular surgical technique induces hydroxyl radical formation in the anterior chamber, which accumulates despite irrigation and aspiration. In this paper we determined the total antioxidant status of aqueous humor after phacoemulsification by measuring aqueous humor ascorbic acid levels. Mixed-breed dogs (n = 11; weighing about 10 kg) with normal eyes as determined by slit-lamp biomicroscopy, applanation tonometry, and indirect ophthalmoscopy had phacoemulsification performed in one eye with the other eye used as a control. Samples of aqueous humor were obtained by anterior chamber paracentesis before surgery and at days 1, 2, 3, 7, and 15 after surgery. Total aqueous humor antioxidant status was inferred from the capacity of aqueous humor to inhibit free radical generation by 2,2-azobis (2-amidopropane) chlorine. Ascorbic acid concentrations were measured by high-pressure liquid chromatography with UV detection. Protein content was determined with the biuret reagent. Statistical analysis was performed by anova followed by the paired t-test. Total antioxidant capacity was reduced from 48 to 27 min during the first 24 h with a gradual increase thereafter, remaining statistically lower than the control eye until 7 days postoperatively. Reduced levels of ascorbic acid followed this reduction in antioxidant capacity (from 211 to 99 microm after 24 h), remaining lower than the control eye until 15 days postoperatively. Protein concentration in aqueous humor increased from 0.62 mg/mL to 30.8 mg/mL 24 h after surgery, remaining statistically lower than the control eye until 15 days postoperatively. Paracentesis alone did not significantly alter the parameters measured. These results indicate that after phacoemulsification, the aqueous humor ascorbic acid levels and antioxidant defenses in aqueous humor are reduced, indirectly corroborating free radical production in the anterior chamber as a result of phacoemulsification. The inflammatory process consequent to the surgical procedure demonstrated by increased protein content in aqueous humor can also contribute to free radical production and ascorbic acid consumption.     

Myocilin protein levels in the aqueous humor of the glaucomas in selected canine breeds

Objective To compare aqueous humor myocilin protein levels in dogs with the primary glaucomas to those with the secondary glaucomas, primary cataracts, and diabetic cataracts. Materials and methods Four groups were selected, based on diagnosis by the attending veterinary ophthalmologists and included: primary glaucoma (primary open‐angle glaucoma (POAG) and primary closed angle glaucoma (PCAG); n = 155); secondary glaucoma (n = 94); primary (presumed inherited) cataract (n = 142), and diabetic cataract (n = 83). A total of 474 samples (187 males, 263 females, 24 unreported) with average ages of 117 months for the males and 101 months for the females were analyzed. Myocilin protein was measured using the Coomassie staining and Western blot methods relative to a myocilin control. Results Differences were seen between nonglaucomatous (cataractous) and glaucomatous dogs with myocilin levels in glaucomatous eyes being many times higher than those in the cataractous dogs. Primary glaucomatous dogs were found to have an aqueous humor myocilin protein level of 17.30 ± 1.03 units. Secondary glaucomas had the highest level of myocilin in the aqueous humor with 19.27 ± 1.41 units. Diabetic cataractous dogs had the lowest levels of myocilin reported with 6.60 ± 0.88 (mean ± SEM) units. Normal (cataractous) dogs had a myocilin level in the aqueous humor of 8.05 ± 0.86 units. Conclusion Aqueous humor protein levels were elevated, relative to the myocilin control, in both the primary and secondary glaucoma groups compared to the cataract and diabetic cataract groups. Like in the Beagle POAG, aqueous humor myocilin protein levels are increased. Further studies are indicated to investigate the exact role of the aqueous humor myocilin protein in the genesis in increased IOP in these primary glaucomatous breeds.     

Population pharmacokinetics of marbofloxacin in aqueous humor after intravenous administration in dogs

OBJECTIVE: To evaluate, by use of population pharmacokinetics, the disposition of marbofloxacin in the aqueous humor after IV administration in dogs and identify its potential usefulness in the prophylaxis and treatment of intraocular infection. ANIMALS: 63 dogs. METHODS: Dogs received a single dose of marbofloxacin (2 mg x kg(-1), IV) at various time intervals before cataract surgery. Aqueous humor and blood samples were collected at the beginning of surgery. Marbofloxacin concentrations were measured by high-pressure liquid chromatography. Data were analyzed with a nonlinear mixed-effect model and, by use of population pharmacokinetic parameters, the time course of aqueous humor concentration was simulated for single doses of 3, 4, and 5.5 mg x kg(-1) IV. Pharmacodynamic surrogate markers and measured aqueous humor concentrations were used to predict in vivo antimicrobial activity. RESULTS: A maximum marbofloxacin concentration of 0.41 +/- 0.17 microg x mL(-1) was reached in the aqueous humor 3.5 hours after IV administration. In the post-distributive phase, marbofloxacin disappeared from aqueous humor with a half-life of 780 minutes. The percentage penetration into the aqueous humor was 38%. Predictors of antimicrobial effects of marbofloxacin (2 mg x kg(-1), IV) indicated that growth of the enterobacteriaceae and certain staphylococcal species would be inhibited in the aqueous humor. Marbofloxacin administered IV at a dose of 5.5 mg x kg(-1) would be predicted to inhibit growth of Pseudomonas aeruginosa and all strains of staphylococci but would not eradicate streptococcal infections. CONCLUSIONS AND CLINICAL RELEVANCE: Marbofloxacin administered IV can penetrate the aqueous humor of canine eyes and may be suitable for prophylaxis or treatment of certain anterior chamber infections.     

Dysplasia of the pectinate ligament and primary glaucoma in the Bouvier des Flandres dog

The eyes of 80 Bouvier des Flandres dogs without a history of clinical eye disease and 43 glaucomatous eyes out of 35 Bouvier des Flandres dogs were examined for changes in the pectinate ligament. Slight to severe dysplasia of the pectinate ligament occurred in 75% of the normotensive eyes. In glaucomatous eyes, dysplasia was severe and similar to the severity of dysplasia in the most affected normotensive eyes. A high percentage of the Bouvier des Flandres dogs in predisposed to develop glaucoma.     

Anterior chamber to frontal sinus shunt for the diversion of aqueous humor: a pilot study in four normal dogs

Silicone tubing was used to divert aqueous humor from the anterior chamber of the right eye to the rostral compartment of the right frontal sinus in four clinically normal mixed-breed dogs. Biomicroscopic examination, and pneumoapplanation tonometry and tonography, completed for up to 18 weeks postoperatively, confirmed gonioimplant function in all four cases. The dogs were euthanized at 6, 8, 16 and 18 weeks postoperatively. Gonioimplant patency was further confirmed by postmortem examination of the globes, implants and frontal sinuses. Gross and light microscopic examinations revealed iridal attachments to the implant ( n  = 4), mild anterior uveitis ( n  = 3), anterior subcapsular cataracts ( n  = 4), and focal corneal ( n  = 3) and scleral ( n  = 3) scarring in the operated globes. Light microscopic examination of frontal sinus specimens revealed mild lymphocytic proliferation and fibrosis immediately adjacent to the implant entrance site. There were no bacteria detected on aerobic or anaerobic cultures of the frontal sinuses or light microscopic examination of the globes or frontal sinuses. Results indicate that the frontal sinus shunting of aqueous humor is a safe and effective means of extraorbital aqueous diversion with potential applicability in the management of glaucoma.     

Laser flaremetric evaluation of experimentally induced blood-aqueous barrier disruption in cats

OBJECTIVES: To determine whether aqueous humor flare, measured by use of laser flaremetry, was proportional to aqueous humor protein concentration and to use laser flaremetry to evaluate disruption of the blood-aqueous barrier (BAB) in cats. ANIMALS: 30 healthy adult cats. PROCEDURE: Laser flaremetry values for all eyes were compared with aqueous humor protein concentrations determined by use of a Coomassie blue microprotein assay. Laser flaremetry was then performed on both eyes before (0 hours) and 4, 8, and 26 hours after initiation of topical application of 2% pilocarpine (q 8 h) to 1 eye of 9 cats or paracentesis of the anterior chamber of 1 eye of 8 cats. Intraocular pressure and pupil size were also determined. Aqueous humor protein concentration was extrapolated from flare values by use of linear regression. RESULTS: There was a linear relationship between flare values and aqueous humor protein concentrations. Topical application of 2% pilocarpine and paracentesis of the anterior chamber caused a breakdown of the BAB that was detected by use of laser flaremetry. The highest mean flare readings after application of pilocarpine or paracentesis were 24.4 and 132.8 pc/ms, respectively, which corresponded to aqueous humor protein concentrations of 85.5 and 434.9 mg/dl, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Paracentesis of the anterior chamber resulted in a more severe breakdown of the BAB in cats than topical application of 2% pilocarpine. Laser flaremetry may be a useful clinical method to detect increases in aqueous flare and, hence, disruptions of the BAB in cats.     

Golden Retriever uveitis: 75 cases (1994-1999)

OBJECTIVE: To document the presenting ocular signs and the clinical course of Golden Retriever dogs with a progressive anterior uveitis, often associated with the histologic presence of iridociliary cysts. Animals studied Seventy-five Golden Retriever dogs (142 affected eyes) referred to a private practice referral ophthalmology clinic between 1994 and 1999. Procedures Complete ophthalmic evaluation with slit-lamp biomicroscopy, indirect ophthalmoscopy, applanation tonometry, and gonioscopy. Hematology, serum biochemical evaluations, and serologic titers for endemic infectious agents were also used in selected cases. RESULTS: The age range of affected dogs was 4.5-14.5 years, with a mean age of 8.6 +/- 2.1 years. The majority of the dogs (n = 66) were affected in both eyes at first presentation. The sex distribution included 4 intact males, 32 neutered males, and 39 spayed females. Hematology, serum biochemical evaluations, and serologic titers for endemic infectious agents failed to demonstrate any underlying disorder. The ophthalmic hallmark of this syndrome was the appearance of pigment on the anterior lens capsule, often in a radial orientation. This capsular pigment was seen both with and without associated uveal cysts. Although single to multiple iridociliary cysts were noted clinically in only 13.3% of the cases, cysts were common on histopathology of advanced glaucomatous, blind eyes. Fibrin was observed in the anterior chamber of 37% of the cases, and often was a precursor for glaucoma. Cataract formation (37%) and glaucoma (46%) were frequent sequelae to the uveitis. Posterior synechiae formation occurred in 50% of the cases. Histopathologic analysis of four enucleated eyes and the eviscerated specimens from 14 glaucomatous eyes demonstrated thin-walled iridociliary epithelial cysts in 3/4 and 12/14 cases, respectively. Microscopically, little to no uveal inflammatory infiltration was commonly noted. Conclusion The overall prognosis for this progressive uveitis in Golden Retriever dogs is guarded, with 46% of the eyes becoming blind due to glaucoma. Iridociliary cysts in Golden Retriever dogs may lead to the development of glaucoma in this breed.     

Lipid-laden aqueous humor associated with anterior uveitis and concurrent hyperlipemia in two dogs.

Two dogs with cloudy aqueous humor due to accumulation of lipid and lipoprotein had concurrent hyperlipemia and anterior uveitis. In 1 dog, serum and aqueous humor had similar lipoprotein electrophoretic patterns, and in the other dog, the patterns were different. The therapeutic approach included symptomatic treatment of the uveitis and reduction of dietary fat intake. Clearing of fat from aqueous humor followed control of the uveitis.     

Fluorophotometric evaluation of experimental blood-aqueous barrier disruption in dogs

A protocol for performing slit-lamp fluorophotometry of the anterior chamber in dogs was established. The technique was then used to develop a model of blood-aqueous barrier disruption that can be used for comparative testing of ophthalmic anti-inflammatory drugs. It was determined that barrier disruption induced by a slow, controlled paracentesis of a small volume of aqueous humor may provide the most reliable model for drug testing. Additionally, fluorophotometry proved to be a sensitive and accurate means of detecting breakdown of the blood-aqueous barrier.     

Effects of topical application of a 2% solution of dorzolamide on intraocular pressure and aqueous humor flow rate in clinically normal dogs

OBJECTIVE: To evaluate effects of topical application of a 2% solution of dorzolamide on intraocular pressure (IOP) and aqueous humor flow rate in clinically normal dogs. ANIMALS: 15 Beagles. PROCEDURE: The IOP was measured in both eyes of all dogs for 3 days to determine baseline values. In a single-dose study, 50 microl of dorzolamide or control solution was applied in both eyes at 7:00 AM, and IOP was measured 7 times/d. In a multiple-dose study, dorzolamide or control solution was applied to both eyes 3 times/d for 6 days, and IOP was measured 4 times/d during treatment and for 5 days after cessation of treatment. Aqueous humor flow rate was measured for all dogs fluorophotometrically prior to treatment and during the multiple-dose study. RESULTS: In the single-dose study, dorzolamide significantly decreased IOP from 30 minutes to 6 hours after treatment. Mean decrease in IOP during this time span was 3.1 mm Hg (18.2%). Maximal decrease was detected 6 hours after treatment (3.8 mm Hg, 22.5%). In the multiple-dose study, dorzolamide decreased IOP at all time points, and maximal decrease was detected 3 hours after treatment (4.1 mm Hg, 24.3%). Mean aqueous humor flow rate decreased from 5.9 to 3.4 microl/min (43%) after treatment in the dorzolamide group. CONCLUSIONS AND CLINICAL RELEVANCE: Topical application of a 2% solution of dorzolamide significantly decreases IOP and aqueous humor flow rate in clinically normal dogs. Therefore, topical administration of dorzolamide should be considered for the medical management of dogs with glaucoma.     

Evaluation of the Krupin-Denver valve implant in normotensive and glaucomatous beagles

The Krupin-Denver valve was implanted unilaterally in 2 normotensive and in 6 glaucomatous Beagles. The fellow eye of each dog had an external trabeculectomy. Before and after surgery, all dogs were evaluated serially by gonioscopy, biomicroscopy, tonometry, and tonography. The valve implant remained patent in 2 normotensive and in 2 glaucomatous Beagles throughout the 12 months of observation. Valve function was lost in 4 glaucomatous Beagles 4 to 6 weeks (3 dogs) and 6 months (1 dog) after implantation. Light microscopic and scanning electron microscopic evaluations of early loss of implant function revealed occlusion of the lumen and/or valve mechanism by inflammatory debris and cells. The late loss of valve function was related to chronic inflammatory response and fibrosis about the valve mechanism and tubing within the sclera.     

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.     

Morphologic features of the aqueous humor drainage pathways in horses

The iridocorneal angle of the horse was anteriorly lined by a pectinate ligament, consisting of several layers of vertically oriented collagenous beams, that were interrupted by a network of extracellular spaces. The anterior chamber angle consisted mostly of a large uveal trabecular meshwork that was composed of widely-spaced, thick trabeculae. These trabeculae were attached in part posteriorly to extensions of the ciliary body musculature and anteriorly inserted into the prominent pectinate ligament. The corneoscleral trabecular meshwork was shaped hemiobovately and formed the external boundary of the iridocorneal angle. The extracellular spaces were smaller and more evenly spaced than those in the uveal trabecular meshwork. Uveal and corneoscleral trabecular meshwork beams were mostly composed of cores of collagen and elastin surrounded by several layers of basement membrane-like material and, in turn, were entirely enveloped by trabecular cells. An anterior narrow zone of broad corneoscleral trabeculae was composed of elastin-collagen cores surrounded by circular bundles of long-spacing collagen. The angular aqueous plexus was extensive, forming much of the external border of the outer corneoscleral trabecular meshwork. A dense zone was associated with the angular aqueous plexus, completely encompassing these aqueous outflow vessels. Posteriorly, the iridocorneal angle was confluent with a well-defined band of trabeculae that was situated between the ciliary body musculature and subjacent sclera and extended posteriorly to the anterior-most region of the choroid where these trabeculae tapered and ended. This region is referred to as the supraciliary trabecular meshwork and indicates a potentially extensive route for outflow of aqueous humor in the equine eye.     

Evaluation of the ocular penetration of topical alpha-luminol (Galavit®/GVT®)

Purpose Oxidative stress plays a major role in the pathogenesis of many neurodegenerative diseases. It has also been implicated as part of the pathogenic mechanisms in the development of glaucoma. Alpha‐luminol has shown profound anti‐inflammatory and antioxidant effects in both experimental animal and human clinical studies. The purpose of this pilot study was to investigate for the first time the ocular penetration of topical alpha‐luminol. Methods Nine animals were divided into three treated groups (three animals each; one drop OU/n = 18), each group receiving a different concentration of the eyedrop (0.5%, 1.5%, 2.5%). Aqueous humor and peripheral blood samples were obtained from each rabbit at three different timepoints (20 min, 4 h and 12 h). Samples were analyzed by means of high performance liquid chromatography and mass spectrometry; median values were compared. Results Alpha‐luminol was found in the aqueous humor in all treated groups at all timepoints. At the 2nd and 3rd timepoints (4 h and 12 h), aqueous humor levels decreased significantly (P < 0.05) for two of the three dosages tested and it was not detectable in some eyes. The highest aqueous humor concentration of the drug was 272 ng/mL after 20 min (0.0217% of one drop, 2.5% group). Alpha‐luminol was found in the vitreous in two animals, one in the 1.5% and another in the 2.5% group (16.4 and 21.5 ng/mL, respectively), at 12 h. Conclusions Topically administered alpha‐luminol readily penetrates into the anterior chamber and can penetrate into the vitreous chamber. Further investigation is warranted to better understand the intraocular pharmacokinetics of alpha‐luminol.