Pediatric ophthalmology (Proceedings)

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Pediatric ophthalmology (Proceedings)

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Nov 01, 2010

• Basic Pediatric Ophthalmic Examination (minimum database)
      - Menace response- not present until 2-3 months of age
      - Palpebral reflex, Dazzle reflex, Pupillary Light Reflex
      - Direct examination with head loops, direct ophthalmoscope
      - Schirmer tear test (can be lower in puppies, ~10mm/min)
      - Fluorescein stain
      - Tonometry (normal to be slightly higher, ~20-25mmHg)

• Normal Pediatric Exam Findings
      - Corneal epithelial opacities
      - Heterochromia iridis
      - Lens capsule pigment deposition
      - Neonate tapetal reflex (blue until 4 months of age)
      - Subalbanotic fundus in blue-eyed animals

• Pediatric Ophthalmic Abnormalities
      - ADNEXA
          ■ Dermoids (congenital mass of tissue in an abnormal position)
          ■ Eyelid agenesis (feline)- involves upper eyelid coloboma; bilateral; can have other anomalies: persistent papillary membranes, choroidal colobomas
          ■ Entropion- temporary eyelid eversion (<11mo. of age), Hotz Celsus (>11mo.)
          ■ Ectropion- Outward rolling of eyelid
                o Conjunctival tissue is exposed
                o Lagophthalmos (inability to close lids completely) may occur
                o Low grade conjunctivitis is most common
          ■ Macroblepharon - Abnormally large palpebral fissure
                o Lagophthalmos leading to instability of pre-corneal tear film which can lead to keratitis
                o A required feature in St. Bernard, Clumber Sp, and Bloodhound
                o Canthalplasty may help reduce size of palpebral fissure
          ■ Distichiasis
                o Hairs that arise from the meibomian gland duct openings
                o In most cases, they are not clinically relevant because fine hairs float in the pre-corneal tear film
                o Can cause irritation and a reflex lacrimation, blepharospasm, conjunctivitis, keratitis, ulceration
                o Cryotherapy for removal
          ■ Ectopic cilia
                o A variant of distichiasis- cilia emerges through the palpebral conjunctiva
                o Typically occurs in upper eyelid
                o Blepharospasms (can be intense)
                o "Non-healing" ulcer in a young dog typically in dorsal cornea
                o Excessive lacrimation
                o Sharp surgical excision, +/- cryotherapy
          ■ Caruncular trichiasis- usually benign, can cause keratitis and eipiphora
      - CONJUNCTIVAL AND LACRIMAL SYSTEM
          ■ Prolapse gland of the third eyelid
                    » Weakness in connective tissue attachment between nictatating membrane ventrum and periorbital tissues
                    » Typically occurs prior to 2 years of age
                    » Chronic conjunctivitis and discharge
                    » Tear production is initially greater than normal eventually becoming subnormal
                    » Surgical replacement recommended- anchoring or pocket technique
          ■ Bent cartilage
                    » Eversion or inversion (rare) of the shaft of the cartilage of the third eyelid
                    » Inherited in German Shorthair pointer, but seen in other breeds
                    » Thought to result from rapid growth of the posterior portion of the cartilage compared to that of the anterior portion
          ■ Papilloma – canine oral papilloma virus in young animals
                    » Lesions can occur on the eyelid, conjunctiva, or cornea
                    » Most spontaneously regress, but ocular forms may not
                    » Wide excision if needed, +/- cryotherapy
          ■ Imperforate punctum/ micropunctum- unilateral or bilateral epiphora
                    » Most common malformation of the nasal-lacrimal duct
                    » Treatment
                         • None, cosmetic
                         • Excise conjunctiva over opening and cannulate for 3 weeks
          ■ Lacrimal gland aplasia and hypoplasia – zero tears at a young age, unilateral, small breed dogs