Diagnostic Ophthalmology Ophtalmologie diagnostique Lynne S. Sandmeyer, Bianca S. Bauer, Bruce H. Grahn
A
History and clinical signs
2-year-old spayed female Cavalier King Charles spaniel was examined at the ophthalmology service at the Western College of Veterinary Medicine for evaluation of a brown mass in the cornea of the left eye. The dog was presented to her referring veterinarian the previous day with acute onset of a red eye and blepharospasm. Topical ofloxacin 0.3% antibiotic solution (PMS-Ofloxacin; Pharmascience, Montreal, Quebec), q6h, and diclofenac sodium 0.1% (Voltaren ophtha; Novartis, Mississauga, Ontario), q8h had been initiated as topical therapy on the left eye prior to presentation. The menace responses, and palpebral, occulocephalic, direct and consensual pupillary light reflexes were present bilaterally. Schirmer tear test (Schirmer Tear Test Strips; Alcon Canada, Mississauga, Ontario) values were 12 and 22 mm/min in the right and left eyes, respectively. The intraocular pressures were estimated with a rebound tonometer (Tonvet; Tiolat, Helsinki, Finland) and were 19 and 14 mmHg in the right and left eyes, respectively. Fluorescein staining (Fluorets; Bausch & Lomb Canada, Markham, Ontario) was positive surrounding the brown structure in the left cornea. On direct examination there was mild conjunctival hyperemia and serous ocular discharge in the left eye. A slightly raised, 2 3 4 mm, roughly oval, brown mass was present in the medial cornea approximately 5 mm from the limbus. Mild corneal edema was noted in the cornea between the mass and the limbus. Both corneas contained axially located, round to oval, faint crystalline opacities. Biomicroscopic examination (Osram 64222; Carl Zeiss Canada, Don Mills, Ontario) revealed the brown mass was superficially located in the corneal stroma. The bilateral axial opacities were consistent with subepithelial lipid deposition. Following application of 0.5% tropicamide (Mydriacyl; Alcon Canada, Mississauga, Ontario) indirect ophthalmoscopic (Heine Omega 200; Heine Instruments Canada, Kitchener, Ontario) examination was completed and did not reveal abnormalities in either eye. A photograph of the left eye at presentation is provided for your assessment (Figure 1).
Department of Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan S7N 5B4. Use of this article is limited to a single copy for personal study. Anyone interested in obtaining reprints should contact the CVMA office ([email protected]) for additional copies or permission to use this material elsewhere. CVJ / VOL 57 / JANUARY 2016
Figure 1. Photograph of the left eye of a 2-year-old Cavalier King Charles spaniel before application of fluorescein stain.
What are your clinical diagnosis, differential diagnoses, therapeutic plan, and prognosis? Discussion The clinical diagnoses were a superficial corneal foreign body of the left eye and associated ulcerative keratitis, as well as mild bilateral corneal dystrophy. Corneal stromal dystrophy is believed to be inherited in the Cavalier King Charles breed (1). The opacities are due to depositions of cholesterol, lipid, and fatty acids within the stroma. In general, corneal stromal dystrophies do not require or respond to medical therapy. Corneal foreign bodies usually present with acute onset of unilateral blepharospasm and tearing. Conjunctival hyperemia and mild surrounding corneal edema are also common. The eye may appear comfortable if the epithelium has healed over the foreign body. The clinical appearance of the foreign material itself is variable; however, plant material is often tan to brown in color. The differential diagnoses for a brown discoloration of the cornea include: corneal pigmentation, corneal sequestrum, dematiaceous fungal keratitis, melanocytic neoplasia, corneal dermoid, uveal prolapse, and corneal foreign body. Pigmentation of the corneal surface is usually a result of chronic irritation or inflammation such as in chronic ulcerative keratitis, chronic superficial keratitis (i.e., pannus), pigmentary keratitis, and 95
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keratoconjunctivitis sicca (2). Corneal sequestrum is most commonly diagnosed in cats; however, there are case reports of this condition in other species including the dog (3,4). The cause of corneal sequestrum is not defined but may involve multiple contributing factors such as chronic irritation related to exposure, desiccation, ulceration, or trauma (3–5). Dematiaceous fungal keratitis of the cornea is rare but can cause a black lesion resembling a corneal sequestrum (6). The most common form of melanocytic neoplasia involving the cornea is limbal melanocytoma which are smooth, pigmented masses that usually have a raised component in the sclera and extend in a shelf-like manner from the limbus into the adjacent cornea (7). Dermoids of the cornea are most commonly located at the limbus, although large dermoids covering most of the cornea have been described. They often contain hairs and other non-corneal tissue, and are present from birth (8). Uveal prolapse occurs with penetrating corneal lesions and is associated with marked uveitis and dyscoria. In this case the clinical appearance and acute onset of clinical signs were most consistent with a corneal foreign body. There are two basic categories of corneal foreign body: superficial and penetrating. Penetrating foreign bodies may enter the anterior chamber and traumatize intraocular structures, including the lens. Penetrating corneal foreign bodies are best treated by microsurgical techniques which may involve primary corneal repair following removal, in addition to phacoemulsification in cases in which lens capsule disruption has resulted in the potential for development of phacoclastic uveitis. Superficial and penetrating corneal foreign bodies may be removed using various techniques, including dislodging with cotton-tipped applicators, needles, and hydropulsion or extraction using metal forceps (9–11). Removal can often be completed using manual restraint and topical anesthetic eye drops. In some cases sedation or short general anesthesia may be required to provide adequate restraint. Ideally, removal should be completed in as atraumatic fashion as possible to avoid damage to the surrounding and underlying cornea. A cotton-tipped applicator is atraumatic but often not sufficient to dislodge firmly adherent foreign material. Hydropulsion is also very atraumatic and has a high success rate. Use of a needle to remove the foreign body carries a small risk of inadvertent corneal laceration or rupture. Using metal forceps for extraction carries a risk of pushing the foreign body deeper into the cornea making removal more difficult and necessitating microsurgery (10). Manual restraint was sufficient in this dog due to its quiet temperament. Following application of topical anesthetic
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(0.5% proparacaine hydrochloride; Alcaine, Alcon Canada, Mississauga, Ontario), a Barraquaer eyelid speculum was placed to maintain the eyelids in an open state. Unsuccessful attempts were made to remove the foreign material by brushing it with a cotton-tipped applicator followed by hydropulsion using a 6 cc syringe filled with eyewash solution attached to a 25-gauge needle with the shaft removed. Finally, a 25-gauge needle tip was used to dislodge the foreign body by applying it at an angle roughly parallel to the base of the foreign body and gently lifting it away from the corneal surface. Head loupes were worn to increase magnification by 23 and improve visualization during the procedure. The superficial corneal ulcer that remained after removal of the foreign material was rinsed with eyewash solution. Topical antimicrobial and non-steroidal anti-inflammatory eye drops were continued until the cornea was confirmed to be fluorescein negative at a recheck examination approximately 1 wk later. Prognosis for superficial corneal foreign bodies is generally excellent. These can usually be removed without need for microsurgery. However, care and attention to provide adequate restraint and apply removal techniques with the minimal amount of corneal trauma are important.
References 1. Sansom J, Blunden T. Calcarious degeneration of the canine cornea. Vet Ophthalmol 2010;13:238–243. 2. Ledbetter EC, Gilger BC. Diseases and surgery of the canine cornea and sclera. In: Gelatt KN, ed. Veterinary Ophthalmology. 5th ed. Ames, Iowa: Wiley-Blackwell, 2013:976–1049. 3. Dubin AJ, Pizzirani S, Beamer GL. Corneal sequestrum in a dog with chronic unilateral keratoconjunctivitis sicca. J Am Vet Med Assoc 2013; 243:1751–1755. 4. Bouhanna L, Liscoet LB, Raymond-Letron I. Corneal stromal sequestration in a dog. Vet Ophthalmol 2008;11:211–214. 5. Featherstone HJ, Sansom J. Feline corneal sequestra: A review of 64 cases (80 eyes) from 1993–2000. Vet Ophthalmol 2004;7:213–227. 6. Pucket JD, Allbaugh RA, Ranking AJ. Treatment of dematiaceous fungal keratitis in a dog. J Am Vet Med Assoc 2012;240:1104–1108. 7. Maggio F, Pizzirani S, Peña T, Leiva M, Pirie CG. Surgical treatment of epibulbar melanocytomas by complete excision and homologous corneoscleral grafting in dogs: 11 cases. Vet Ophthalmol 2013;16:56–64. 8. Brudenall DK, Bernays ME, Peiffer RL, Jr. Central corneal dermoid in a Labrador retriever puppy. J Small Anim Pract 2007;48:588–590. 9. Williams DL, Barrie K, Evans TF. Cornea. In: Williams DL, Barrie K, Evans TF, eds. Veterinary Ocular Emergencies. Edinburgh: Butterworth Heinemann, 2002:60–63. 10. Maggs DJ. Cornea and sclera. In: Maggs DJ, Miller PE, Ofri R, eds. Slatter’s Fundamentals of Veterinary Ophthalmology. 5th ed. St. Louis, Missouri: Elsevier Saunders, 2013:202–203. 11. Labelle AL, Psutka K, Collins SP, Hamor RE. Use of hydropulsion for the treatment of superficial corneal foreign bodies: 15 cases (1999–2013). J Am Vet Med Assoc 201;244:476–479.
CVJ / VOL 57 / JANUARY 2016
A
History and clinical signs
2-year-old spayed female Cavalier King Charles spaniel was examined at the ophthalmology service at the Western College of Veterinary Medicine for evaluation of a brown mass in the cornea of the left eye. The dog was presented to her referring veterinarian the previous day with acute onset of a red eye and blepharospasm. Topical ofloxacin 0.3% antibiotic solution (PMS-Ofloxacin; Pharmascience, Montreal, Quebec), q6h, and diclofenac sodium 0.1% (Voltaren ophtha; Novartis, Mississauga, Ontario), q8h had been initiated as topical therapy on the left eye prior to presentation. The menace responses, and palpebral, occulocephalic, direct and consensual pupillary light reflexes were present bilaterally. Schirmer tear test (Schirmer Tear Test Strips; Alcon Canada, Mississauga, Ontario) values were 12 and 22 mm/min in the right and left eyes, respectively. The intraocular pressures were estimated with a rebound tonometer (Tonvet; Tiolat, Helsinki, Finland) and were 19 and 14 mmHg in the right and left eyes, respectively. Fluorescein staining (Fluorets; Bausch & Lomb Canada, Markham, Ontario) was positive surrounding the brown structure in the left cornea. On direct examination there was mild conjunctival hyperemia and serous ocular discharge in the left eye. A slightly raised, 2 3 4 mm, roughly oval, brown mass was present in the medial cornea approximately 5 mm from the limbus. Mild corneal edema was noted in the cornea between the mass and the limbus. Both corneas contained axially located, round to oval, faint crystalline opacities. Biomicroscopic examination (Osram 64222; Carl Zeiss Canada, Don Mills, Ontario) revealed the brown mass was superficially located in the corneal stroma. The bilateral axial opacities were consistent with subepithelial lipid deposition. Following application of 0.5% tropicamide (Mydriacyl; Alcon Canada, Mississauga, Ontario) indirect ophthalmoscopic (Heine Omega 200; Heine Instruments Canada, Kitchener, Ontario) examination was completed and did not reveal abnormalities in either eye. A photograph of the left eye at presentation is provided for your assessment (Figure 1).
Department of Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan S7N 5B4. Use of this article is limited to a single copy for personal study. Anyone interested in obtaining reprints should contact the CVMA office ([email protected]) for additional copies or permission to use this material elsewhere. CVJ / VOL 57 / JANUARY 2016
Figure 1. Photograph of the left eye of a 2-year-old Cavalier King Charles spaniel before application of fluorescein stain.
What are your clinical diagnosis, differential diagnoses, therapeutic plan, and prognosis? Discussion The clinical diagnoses were a superficial corneal foreign body of the left eye and associated ulcerative keratitis, as well as mild bilateral corneal dystrophy. Corneal stromal dystrophy is believed to be inherited in the Cavalier King Charles breed (1). The opacities are due to depositions of cholesterol, lipid, and fatty acids within the stroma. In general, corneal stromal dystrophies do not require or respond to medical therapy. Corneal foreign bodies usually present with acute onset of unilateral blepharospasm and tearing. Conjunctival hyperemia and mild surrounding corneal edema are also common. The eye may appear comfortable if the epithelium has healed over the foreign body. The clinical appearance of the foreign material itself is variable; however, plant material is often tan to brown in color. The differential diagnoses for a brown discoloration of the cornea include: corneal pigmentation, corneal sequestrum, dematiaceous fungal keratitis, melanocytic neoplasia, corneal dermoid, uveal prolapse, and corneal foreign body. Pigmentation of the corneal surface is usually a result of chronic irritation or inflammation such as in chronic ulcerative keratitis, chronic superficial keratitis (i.e., pannus), pigmentary keratitis, and 95
O P H TA LM O LO G I E D I AG N O S T I Q U E
keratoconjunctivitis sicca (2). Corneal sequestrum is most commonly diagnosed in cats; however, there are case reports of this condition in other species including the dog (3,4). The cause of corneal sequestrum is not defined but may involve multiple contributing factors such as chronic irritation related to exposure, desiccation, ulceration, or trauma (3–5). Dematiaceous fungal keratitis of the cornea is rare but can cause a black lesion resembling a corneal sequestrum (6). The most common form of melanocytic neoplasia involving the cornea is limbal melanocytoma which are smooth, pigmented masses that usually have a raised component in the sclera and extend in a shelf-like manner from the limbus into the adjacent cornea (7). Dermoids of the cornea are most commonly located at the limbus, although large dermoids covering most of the cornea have been described. They often contain hairs and other non-corneal tissue, and are present from birth (8). Uveal prolapse occurs with penetrating corneal lesions and is associated with marked uveitis and dyscoria. In this case the clinical appearance and acute onset of clinical signs were most consistent with a corneal foreign body. There are two basic categories of corneal foreign body: superficial and penetrating. Penetrating foreign bodies may enter the anterior chamber and traumatize intraocular structures, including the lens. Penetrating corneal foreign bodies are best treated by microsurgical techniques which may involve primary corneal repair following removal, in addition to phacoemulsification in cases in which lens capsule disruption has resulted in the potential for development of phacoclastic uveitis. Superficial and penetrating corneal foreign bodies may be removed using various techniques, including dislodging with cotton-tipped applicators, needles, and hydropulsion or extraction using metal forceps (9–11). Removal can often be completed using manual restraint and topical anesthetic eye drops. In some cases sedation or short general anesthesia may be required to provide adequate restraint. Ideally, removal should be completed in as atraumatic fashion as possible to avoid damage to the surrounding and underlying cornea. A cotton-tipped applicator is atraumatic but often not sufficient to dislodge firmly adherent foreign material. Hydropulsion is also very atraumatic and has a high success rate. Use of a needle to remove the foreign body carries a small risk of inadvertent corneal laceration or rupture. Using metal forceps for extraction carries a risk of pushing the foreign body deeper into the cornea making removal more difficult and necessitating microsurgery (10). Manual restraint was sufficient in this dog due to its quiet temperament. Following application of topical anesthetic
96
(0.5% proparacaine hydrochloride; Alcaine, Alcon Canada, Mississauga, Ontario), a Barraquaer eyelid speculum was placed to maintain the eyelids in an open state. Unsuccessful attempts were made to remove the foreign material by brushing it with a cotton-tipped applicator followed by hydropulsion using a 6 cc syringe filled with eyewash solution attached to a 25-gauge needle with the shaft removed. Finally, a 25-gauge needle tip was used to dislodge the foreign body by applying it at an angle roughly parallel to the base of the foreign body and gently lifting it away from the corneal surface. Head loupes were worn to increase magnification by 23 and improve visualization during the procedure. The superficial corneal ulcer that remained after removal of the foreign material was rinsed with eyewash solution. Topical antimicrobial and non-steroidal anti-inflammatory eye drops were continued until the cornea was confirmed to be fluorescein negative at a recheck examination approximately 1 wk later. Prognosis for superficial corneal foreign bodies is generally excellent. These can usually be removed without need for microsurgery. However, care and attention to provide adequate restraint and apply removal techniques with the minimal amount of corneal trauma are important.
References 1. Sansom J, Blunden T. Calcarious degeneration of the canine cornea. Vet Ophthalmol 2010;13:238–243. 2. Ledbetter EC, Gilger BC. Diseases and surgery of the canine cornea and sclera. In: Gelatt KN, ed. Veterinary Ophthalmology. 5th ed. Ames, Iowa: Wiley-Blackwell, 2013:976–1049. 3. Dubin AJ, Pizzirani S, Beamer GL. Corneal sequestrum in a dog with chronic unilateral keratoconjunctivitis sicca. J Am Vet Med Assoc 2013; 243:1751–1755. 4. Bouhanna L, Liscoet LB, Raymond-Letron I. Corneal stromal sequestration in a dog. Vet Ophthalmol 2008;11:211–214. 5. Featherstone HJ, Sansom J. Feline corneal sequestra: A review of 64 cases (80 eyes) from 1993–2000. Vet Ophthalmol 2004;7:213–227. 6. Pucket JD, Allbaugh RA, Ranking AJ. Treatment of dematiaceous fungal keratitis in a dog. J Am Vet Med Assoc 2012;240:1104–1108. 7. Maggio F, Pizzirani S, Peña T, Leiva M, Pirie CG. Surgical treatment of epibulbar melanocytomas by complete excision and homologous corneoscleral grafting in dogs: 11 cases. Vet Ophthalmol 2013;16:56–64. 8. Brudenall DK, Bernays ME, Peiffer RL, Jr. Central corneal dermoid in a Labrador retriever puppy. J Small Anim Pract 2007;48:588–590. 9. Williams DL, Barrie K, Evans TF. Cornea. In: Williams DL, Barrie K, Evans TF, eds. Veterinary Ocular Emergencies. Edinburgh: Butterworth Heinemann, 2002:60–63. 10. Maggs DJ. Cornea and sclera. In: Maggs DJ, Miller PE, Ofri R, eds. Slatter’s Fundamentals of Veterinary Ophthalmology. 5th ed. St. Louis, Missouri: Elsevier Saunders, 2013:202–203. 11. Labelle AL, Psutka K, Collins SP, Hamor RE. Use of hydropulsion for the treatment of superficial corneal foreign bodies: 15 cases (1999–2013). J Am Vet Med Assoc 201;244:476–479.
CVJ / VOL 57 / JANUARY 2016
