Combined corneal lipid and calcium degeneration in a dog with hyperadrenocorticism: a case report

Dissolution of presumed calcareous corneal degeneration with 13.8% ethylenediaminetetraacetic acid solution in 17 dogs

PURPOSE

To describe a novel treatment for dissolving calcareous corneal degeneration (CCD)-associated mineral in 17 dogs with 13.8% ethylenediaminetetraacetic acid (EDTA) solution.

METHODS

Cases seen between 2021 and 2023 were reviewed. Seventeen dogs with CCD associated with corneal ulcerations were treated with a mineral dissolution procedure using 13.8% EDTA solution. A diamond burr keratotomy (DBK) was subsequently performed in some cases when residual mineralization remained present.

RESULTS

Of the 19 eyes (17 dogs) included in the study, 10 eyes (8 dogs) required a DBK procedure. One eye (one dog) required a repeat procedure 26 weeks following the initial procedure and two eyes (one dog) required a repeat procedure 24 and 37 weeks following initial treatment in the left and right eye, respectively. Mean follow-up time to last recheck for eyes not requiring a second chelation procedure was 20.4 weeks (range, 10-47 weeks). At the last follow-up examination for all 17 dogs, the CCD resolved in 26.3%, improved in 57.9%, and recurred in 15.8% of eyes. Complications occurred in two eyes (two dogs) and included an infected stromal ulcer at 2-week recheck and the creation of a 40% depth stromal defect immediately following debridement. Both complications were successfully addressed with medical management.

CONCLUSIONS

The utilization of 13.8% EDTA solution appears to be an effective and safe means of treating lesions associated with CCD.

The relationship between corneal calcareous degeneration and various ophthalmic diseases in dogs: A retrospective study

OBJECTIVE

To investigate ocular factors that influence the development of corneal calcareous degeneration (CCD) in dogs.

ANIMALS AND PROCEDURES

The medical records of 96 eyes of dogs with CCD and 288 eyes without CCD were retrospectively reviewed. Dogs with evidence of causative systemic illness associated with CCD were excluded from the study. Logistic regression analysis was used to identify the ocular factors associated with the development of CCD. To identify the effect of phosphate-containing eyedrops on CCD, the application periods of phosphate-containing antiglaucoma eyedrops were compared between the glaucomatous eyes in the CCD and non-CCD groups.

RESULTS

Increased age, brachycephalic breed, keratoconjunctivitis sicca, advanced cataract, history of phacoemulsification, and topical corticosteroid application were significantly associated with CCD development. Glaucoma was significantly overrepresented in the non-CCD group, and the application period of phosphate-containing antiglaucoma eyedrops was significantly longer in eyes with CCD than in those without CCD.

CONCLUSIONS

Ophthalmic diseases requiring long-term management of ocular inflammation and long-term application of phosphate-containing eyedrops may contribute to the development of CCD. Glaucoma is overrepresented in dogs without CCD, which is thought to be due to the differences in predisposed age and breeds between dogs with glaucoma and CCD.

Topical Ethylenediaminetetraacetic acid (EDTA) administration following corneal diamond burr keratotomy for calcareous corneal degeneration in canines

OBJECTIVE

To evaluate the outcomes of canine patients diagnosed with corneal ulceration associated with presumed calcareous corneal degeneration (CCD) that were treated with diamond burr keratotomy (DBK) and ongoing postoperative topical 3% or 4% Ethylenediaminetetraacetic acid (EDTA).

PROCEDURES

Retrospective assessment of CCD cases treated with ongoing topical EDTA following DBK between 2011 and 2020 at Veterinary Ophthalmic Referrals. Descriptive statistics of the study population were assessed, and a survival analysis was performed using R statistical software.

RESULTS

A total of 51 eyes from 41 dogs were assessed, with small terrier breeds overrepresented (27/41, 65.9%). Median age of dogs at the time of diagnosis was 14.3 years (range 8-17.2 years). Following DBK, the median time to commencement of topical EDTA was 11 days (range 0-28 days). Cases were followed for a median duration of 216 days (range 42-1379 days). Corneal ulceration recurred in 7/51 (13.7%) eyes at a median duration of 80 days (range 63-156 days). The probability of recurrence of corneal ulceration associated with CCD at 12 months was 15.6% (95% CI: 4.1-25.7%). A second DBK procedure followed by ongoing topical EDTA was performed in 4/7 (57.1%) of the recurred eyes. These retreated eyes had no further recurrence recorded and a median follow-up time of 401 days (range 120-858 days).

CONCLUSION

Ongoing topical EDTA following DBK is an effective adjunct treatment method for CCD with reduced rates of recurrence of CCD-associated corneal ulceration when compared to published rates of recurrence when treated with DBK alone.

Once in a blue moon: Lipid keratopathy and intrastromal hemorrhage in a Mission golden-eyed tree frog (Trachycephalus resinifictrix)

Mimicking natural anuran biology is a major challenge faced in the husbandry management of frogs, and the quandary of lipid keratopathy in frogs under human care has plagued keepers and practitioners for decades. Unlike corneal lipid dystrophy or lipidosis secondary to degeneration, where there is limited or no vascular in-growth or inflammatory response, lipid keratopathies are associated with vascularization, most often following the appearance of lipid. Hemorrhage from stromal neovascularization has not been described in a frog; however, the presence of vessels in lipid keratopathy certainly heralds the possibility. We report a rather unique case of lipid keratopathy in a 6-year-old female Mission golden-eyed tree frog (Trachycephalus resinifictrix) that not only had concurrent intrastromal hemorrhage, but blue plasmoid staining of the corneal stroma. Current views on both the function of blue plasma in several species and lipid keratopathy are briefly discussed. Overall, evidence suggests that the cause of lipid keratopathy is probably multifactorial and will not successfully be rectified until anuran biology and husbandry are better understood.

Lipoidal corneal degeneration in aged falcons

OBJECTIVE

To present a case series of idiopathic lipoidal corneal degeneration in falcons.

ANIMALS STUDIED

Five falcons including three peregrine falcons (Falco peregrinus), one prairie falcon (Falco mexicanus), and one red-naped shaheen (Falco peregrinus babylonicus) were observed to develop slowly progressive corneal opacification that began at the temporal limbus and extended centripetally across the cornea over a period of years. Four of the birds were over 20 years old.

PROCEDURES

All animals underwent complete ophthalmic examinations. A red-naped shaheen underwent ocular imaging via spectral-domain optical coherence tomography. Two peregrine falcons were euthanized due to declining health, and their eyes were examined histologically.

RESULTS

The opacities were pale and granular, with frequent vascularization associated perilimbally. Diffuse neutral lipid was observed in stromal cells throughout the corneal stroma of both clear and opaque areas of the cornea, sparing only the acellular anterior limiting lamina. Clusters of cholesterol crystals surrounded by macrophages were present in the mid-stroma. Fibrosis was evident in a subepithelial location, which separated the epithelium from the anterior limiting lamina. Ultrastructurally, diffuse vacuolization of the keratocytes was observed. No other ophthalmic or systemic abnormalities were noted.

CONCLUSIONS

Results suggest that lipid degeneration occurs rarely in captive falcons of advanced age. The underlying cause is unclear. Though unsubstantiated, possible contributing factors include dyslipoproteinemia, corneal trauma, diet, and age-related alterations in corneal metabolism. The initiation of pathology at the temporal limbus, as well as slow progression, suggests that exposure contributes to the onset and progression of this unique keratopathy.

Scleral and corneal xanthomatous inflammation in a gray mouse lemur (Microcebus murinus)

Bilateral multifocal corneal opacity was detected in a 4.5-year-old male captive gray mouse lemur (Microcebus murinus) without other clinical ocular changes. Histopathological examination revealed a severe diffuse granulomatous scleritis and focal keratitis with intralesional cholesterol, consistent with xanthomatous inflammation. This is the first report of xanthomatous inflammation in a gray mouse lemur. This condition may be the result of systemic factors (lipid metabolism disorders) and/or local predisposing factors such as hemorrhage or inflammation. The pathogenesis in this case could not be fully determined. Further studies on lemurs are required for a better understanding of their lipid metabolism, as well as for diagnosing and evaluating the incidence of xanthomatous inflammation in these species.

Comparison of corneal degeneration and calcific band keratopathy from 2000 to 2013 in 69 horses

OBJECTIVE

To compare signalment, presentation, treatment, and outcome in horses diagnosed with corneal degeneration (CD) or calcific band keratopathy (CBK) at a referral hospital.

ANIMALS STUDIED

Sixty-nine horses (87 eyes) diagnosed with either CD or CBK.

PROCEDURES

Medical records of horses diagnosed with CD or CBK at the University of California-Davis Veterinary Medical Teaching Hospital (UCD-VMTH) between 2000 and 2013 were reviewed. Signalment, concurrent ophthalmic diagnoses, previous therapies, diagnostic tests, systemic diagnoses, treatment, follow-up, and outcomes were compared between horses diagnosed with CD or CBK. Age, breed, and gender were compared between the CD/CBK and UCD-VMTH populations.

RESULTS

Thirty-three horses (42 eyes) and 36 horses (45 eyes) were diagnosed with CD and CBK, respectively. Horses with CD or CBK were significantly older (P < 0.001) than the UCD-VMTH population with a median age of 16 or 18 years, respectively. Appaloosas were significantly overrepresented in the CD/CBK population (33%) in comparison with the UCD-VMTH population (1.8%, P < 0.001). Equine recurrent uveitis was concurrently diagnosed in 67% and 84% of horses with CD or CBK, respectively. Pituitary pars intermedia dysfunction (PPID) was diagnosed significantly less often in horses with CD vs. CBK (P = 0.03). Chemical chelation with ethylenediaminetetraacetic acid was performed significantly less frequently in horses diagnosed with CD (7.1%) vs. CBK (31.1% of eyes) (P = 0.012).

CONCLUSIONS

Despite some differences, equine CD and CBK are relatively similar conditions and may represent a continuum of disease severity. Horses with PPID should be monitored closely for corneal disease including CBK.

Diamond burr debridement of 34 canine corneas with presumed corneal calcareous degeneration

OBJECTIVES

To describe the signalment, presence of systemic and/or ocular comorbidities, times to detected healing and probabilities of recurrence after diamond burr debridement (DBD) of eyes with presumed corneal calcareous degeneration and secondary ulceration and/or ocular pain.

ANIMALS STUDIED

Twenty-six dogs with 42 eyes affected, 34 eyes treated with DBD.

METHODS

A case series was conducted using medical records from a private veterinary ophthalmology referral practice. Dogs were included if they had white or gray corneal opacity consistent with corneal calcareous degeneration with either erosive or superficial ulceration and/or ocular pain in at least one eye and had at least one such eye treated with DBD. DBD was performed with a battery-operated handheld motorized burr (The Alger Company, Inc. Lago Vista, TX, USA), and a bandage contact lens was placed in the majority of eyes (30/34). Eyes were considered healed when the cornea was fluorescein negative, and there were no signs of ocular pain. Patient data (signalment, recurrence) were extracted from medical records.

RESULTS

Dogs were first re-examined 7-62 days after treatment (median: 13 days). All DBD-treated eyes healed within 62 days (% healed: 100%; one-sided 97.5% CI: 90-100%, median: 14 days), 82% of eyes (28/34) were healed at first re-examination (median: 13 days after treatment), and all were healed by their second examination (median: 24 days). Of the 34 treated eyes, 11 were lost to follow up; 11 of the remaining 23 eyes recurred. Estimated 1-year recurrence probability was 58% (95% CI: 35-83%). Seven dogs had systemic disease; 7 had a history of prior ocular disease or intraocular surgery.

CONCLUSIONS

Diamond burr debridement is a safe and effective treatment for rapid resolution of superficial corneal ulceration and ocular pain secondary to presumed corneal calcareous degeneration in dogs.

Calcific band keratopathy in an alpaca

A 4-year-old female Suri alpaca was presented for evaluation of acute onset weakness, lethargy, and recent development of opacities in both eyes. On ophthalmic examination, bilaterally symmetrical corneal opacities were noted along the interpalpebral fissures with a few corneal blood vessels intermingled. A presumed diagnosis of calcific band keratopathy was made based on location and appearance. The patient was euthanized a short while after diagnosis due to reasons unrelated to the eyes and histologic examination of the corneas revealed subepithelial calcium and vascularization, consistent with calcific band keratopathy. This case report is the first to document this ocular condition in an alpaca.

Calcareous degeneration of the canine cornea

The purpose of this paper is to describe a specific presentation of canine corneal calcification. Fourteen cases are described. In seven cases the corneal lesions were bilaterally symmetrical. In five cases the corneal lesion was unilateral. Two dogs were uniocular, the contralateral eye had been enucleated between 1 and 3 months previously by the referring veterinary surgeon following corneal ulceration and perforation. Of a total of 21 eyes with corneal calcification, 16 eyes had associated ulceration. The ulceration presented as follows: two eyes had descemetocoeles, four eyes had corneal perforations, eight eyes had stromal ulceration, and two eyes had superficial punctate ulceration. The cause of the corneal mineralization remains undetermined but underlying systemic disease, particularly hyperadrenocorticism (Cushing's Syndrome), is suspected as a possible contributing factor in some of these cases. Histopathology was carried out on three cases following a keratectomy and placement of a conjunctival pedicle flap into the ulcerated lesion.