Basic Diagnostic Methods Flashcards
List the process when examining ophthalmic cases
- History
- Physical exam (general)
- Ophthalmic exam
- Additional diagnostic techniques
What should you consider during the general physical exam in ophthalmic cases
- Systemic diseases
- Neurologic diseases
Both may be accompanied by ocular signs
What should be considered before performing the ophthalmic exam?
Restraint for examination
- Manual restraint
- Sedation
General anaesthesia is usually a drawback in the ophthalmic exam
Give the steps of the ophthalmic exam
- Examination of head, periocular area & globe
- Preliminary ocular exam
- Detailed physical exam of eye
- Additional diagnostic techniques
Ophthalmic exam: Examination of head & periocular area
Inspect & palpate in a light room
Normal:
- Periocular area is symmetric, no gap, scar or inadequate movement of the bones.
Ophthalmic exam: Globe
Inspect & palpate in a light room
Normal:
- Both globes are the same size & shape; symmetric, tightly undulating & painless
- Optical axes of the globes meet on a demonstrative object.
Give the steps of the preliminary ocular exam
- PLR (Pupillary Light Reflex)
- STT (Schirmer Tear Test)
- Specimen collection
- Vision evaluation
Preliminary ocular exam: PLR (Pupillary light reflex)
Light → Constriction of the pupil
- Inspect the speed & intensity
- Normal: Symmetric reaction with equal intensity
Preliminary ocular exam: STT (Schirmer Tear Test)
- Semiquantitative measurement of tear production
- Indication: Dry-eye inflammation (KCS)
- Test strip applied for 1 minute
Preliminary ocular exam: Interpretation of the Schirmer tear test
Normal = > 14 mm/min
Apparent disease = < 5 mm/min
Preliminary ocular exam: Specimen collection
- Indication: Severe purulent inflammation; resistance to therapy; melting corneal ulcers; inflammation of the eyelids
- Cytological or microbiological exam
- Samples should be taken before any topical anaesthesia is applied
Preliminary ocular exam: Specimen collection may be from which locations?
- Cornea
- Conjunctiva
- Corneoconjunctival region
- Eyelid
Preliminary ocular exam: Steps of the vision evaluation
- Falling cotton test
- Obstacle test
- Menace reflex test
Summarise the falling cotton test
Nomal dx: The falling cotton is visually followed
Summarise the obstacle test
Normal dx: Negotiation of the obstacles is not impaired
Summarise the menace reflex test
Normal dx: The animal blinks and/or flinches when a threatening movement is given
Detailed physical exam of the eye: How are these exams performed?
- Under magnification
- Focal light source
- Darkened room
Detailed physical exam of the eye: Structures examined
- Palpebral fissure
- Eyelids
- Third eyelid
- Conjunctiva
- Lacrimal system
- Cornea
- Sclera
- Anterior chamber
- Iris & pupil
- Lens
- Vitreous body
Detailed physical exam of the eye: Palpebral fissure
Normal dx:
- Symmetric and wide in the middle
- Ø Discharge
Detailed physical exam of the eye: Eyelids
Inspection & palpation
Normal dx:
- Skin is thin, folded and moves freely
- Margin of the lids is regular
- The glandular opening is seen (grey line)
Which species are lacking the lower ciliae (eyelash)
- Cat
- Horse
- Cow
Which species have multiple rows of upper ciliae?
Dog
Detailed physical exam of the eye: Third eyelid
Inspection & palpation
Normal dx:
- Fits the globe; only the free margin is visible at the medial canthus
- Palpebral surface: Pink, moist, slightly vascularised
- Bulbar surface: Fresh red, velvet-like, pale-pink follicles
Detailed physical exam of the eye: Conjunctiva
Inspection & palpation
Normal dx:
- Pale pink, gently folded, moistly shining
- Barely any visible conjunctival vessels
- Ventral fornix is hyperaemic w/ lymphoid follicles
Detailed physical exam of the eye: Lacrimal system
Inspection of the lacrimal puncta (entry to the tearduct)
Normal dx:
- Upper & lower puncta are 3mm from the medial canthus
Detailed physical exam of the eye: Cornea
Inspection & ‘palpation’
Normal dx:
- Uniformly glistening
- Completely transparent & avascular
- Animal should blink when a wisp of cotton touches cornea
Detailed physical exam of the eye: Sclera
Inspection only
Normal dx:
- Only a small part can be examined
- Smooth, whitish; no scar or gap
- Pigmentation from the point of the limbus
Detailed physical exam of the eye: Anterior chamber
Inspection only
Normal dx:
- Depth varies between species
- Aq. humor is completely transparent; Ø content
Detailed physical exam of the eye: Abnormal contents of the anterior chamber
- Hypopyon: Pus in the anterior chamber
- Hyphema: Blood in the anterior chamber
Detailed physical exam of the eye: Iris & pupil
Inspection only
Normal dx:
- Centrally placed; gentle circular pattern
- Herbivores may have corpora nigrum
Shapes of the pupil across the species
- Horizontal elliptical: Horse, cow & pig
- Rounded: Dog
- Perpendicular rhomboid: Cat
Detailed physical exam of the eye: Lens
Inspection only
Normal dx:
- Purkinje’s images formed on the anterior & posterior lens capsule
- Ø Opacity in the lens
Detailed physical exam of the eye: Vitreous body
Inspection only
Normal dx:
- Vitreous is clear - Ø Opacity
Give the vital staining methods
- Fluorescein
- Rose bengal
Vital staining: Fluorescein
- Water-soluble, hydrophilic; orange colour
- Solution/impregnated strips
- Strips ↓ chance of infection
- Fluorescein stains the exposed stroma bright green
Vital staining: Indication for fluorescein
Assessment of the corneal epithelium’s condition
- Suspicion of corneal ulcer/injury
- All cases when the eye is red/painful
- Before topical/subconjunctival steroid therapy
Vital staining: Rose Bengal
- Water soluble, hydrophilic; red colour
- Stains the degenerated, necrotic cells & mucus red
Vital staining: Indication for Rose Bengal staining
Any suspicion of dry-eye inflammation
Early dx of KCS
