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Red eye - Coggle Diagram

- - - - corneal or scleral rupture may present with red eye, but these patients should be minimally manipulated and treated as fragile eye
  - - - corneal cytology, c+s
    - - Gonioscopy
    - - systemic investigations, ocular USS
    - - MRI/CT
    - - not confident with dx or tx
      - unable to perform complete ophthalmic exam
      - risk of losing eye or sight
      - complex cases or cases requiring further investigation
- - - - red periocular tissue
      - may involve skin, muscles, meibomian glands and conjunctiva
      - hyperaemia, swelling, ulcers, crusts, loss of hair
      - periocular dermatitis
        
        several causes
        
        some systemic and potentially severe
        
        uveodermatological syndrome
      - meibomian glands
        
        can become infected, inflamed or neoplastic
      - abnormal eyelids can affect the cornea and tear film
        
        loss of protective effect
        
        loss of oily component of tears
        
        abnormal contact
        
        hairs or masses contacting ocular surface
        
        leads to...
        
        irritation of white of eye
        
        conjunctival hyperaemia
        
        corneal irritation
        
        corneal neovascularisation and ulceration
    - - red ocular casts
      - Conjunctiva: mucous membrane lining eyelids, third eyelid and sclera
        
        structures involved: epithelium, mucin cells (goblet cells), lymphoid tissues, blood vessels (with dichotomous division, appear superficial and move with conjunctiva, most evident in fornixes).
        
        normal
        
        conjunctival vasculature present, but minimal
        
        episcleral vasculature rarely seen in normal conditions
      - hyperaemia, swelling, ulcers and lymphoid follicles
      - conjunctival hyperaemia
        
        sign of ocular surface disease
        
        dichotomous division, superficial and move with conjunctiva
        
        most evident at fornixes
      - episclera/sclera
        
        red ocular coats
        
        fibrous tunic of globe
        
        collagen
        
        blood vessels
        
        no dichotomous division, deeper and do not move with conjunctiva
        
        most evident close to limbus
        
        hyperaemia and swelling
        
        episcleral hyperaemia
        
        sign of deeper ocular tissue disease (including intraocular)
        
        no division, deeper and do not move with conjunctiva
        
        most evident close to limbus
        
        straight and deep red, vessels stationary and most evident closer to the limbus
    - - red ocular coats
      - cartilage, lymphoid tissue and accessory lacrimal gland
      - Tshape cartilage
        
        holds the third eyelid up against the eye
        
        can curl and cause an outword fold
      - large amount of lymphoid tissue
        
        very prominent in some cases
        
        young animals, allergies, certain infections in cats
        
        mainly present in the inner side and usually accompanied by hyperaemia
      - contains accessory lacrimal gland
        
        produces up to 30% of aqueous component of tears
        
        can prolapse and become inflamed
      - Normal third eyelid
        
        some vasculature is visible, but minimal
        
        variable pigmentation - poorly pigmented TEL can appear redder than pigmented TEL
      - TEL hyperaemia and swelling
        
        ocular surface disease
        
        orbital disease
        
        TEL neoplasia
      - TEL follicular proliferation
        
        young animals, allergies and certain infections (cats)
        
        mainly present in the inner side
        
        usually accompanied by hyperaemia
      - scrolled cartilage v prolapse nictitants gland can be clinically similar
        
        may need to manipulate TEL under topical anaesthesia to differentiate both conditions
        
        prolapsed gland (cherry eye)
        
        scrolled cartilage
    - - red ocular coat
      - anterior part of the fibrotic tunic of the globe
      - corneal neovascularisation +/- intracorneal bleed
      - superficial corneal neovasculariation
        
        sign of ocular surface disease
        
        dichotomous division, long and branching
        
        may occur with or without corneal neovascularisation
        
        ulcerative keratitis
        
        conjunctival hyperaemia
        
        superficial corneal neovascularisation
        
        fluorescein stain (positive) STT1 (variable)
        
        keratoconjunctivitis sicca (dry eye)
        
        conjunctival hyperaemia and ocular discharge
        
        superficial corneal neovascularisation
        
        fluorescein stain (variable) - STT1 (Low)
        
        Deep corneal neovascularisation
        
        sign of deeper ocular tissues disease (including intraocular)
        
        short straight and deep red
        
        usually stay close to limbus (look like a bush)
        
        uveitis
        
        episcleral hyperaemia and deep corneal neovascularisation
        
        small pupil (miosis)
        
        low intraocular pressure
        
        glaucoma
        
        episcleral hyperaemia and deep corneal neovascularisation
        
        dilated pupils (mydriasis)
        
        high intraocular pressure
      - intracorneal haemorrhage (uncommon)
        
        always associated with corneal neovascularisation
        
        can be associated with systemic dz (systemic hypertension)
- - - - white blood cells
        
        hypopion
      - proteins
        
        aqueous flare
      - fibrin
        
        fibrinous uveitis
    - - inflammation (uveitis)
      - trauma (penetrating or blunt)
      - intraocular neoplasia
      - retinal detachment
      - glaucoma
      - congenital defect
      - systemic condition
        
        hypertension, thrombopathy, coagulopathy
  - - - uveal bleed
      - uveal tumour
      - engorgement of normal vascularisation
        
        most commonly secondary to uveitis
      - formation of new vasculature over the iris surface
        
        histologically referred as pre-iridal fibrovascular membranes
        
        secondary to uveitis, intraocular tumour, retinal detachment or glaucoma
  - - - similar to anterior uvea with tapetum lucidum
    - - neuronal cells and retinal vasculature
    - - some anatomical variations can mimic retinal/choroidal bleeds
        
        some lightly pigmented animals can present a marked red reflexion of the ocular fundus due to lack of pigmentation in the posterior uvea and retinal pigmented epithelium
  - - - extra ocular musculature, nerves and vessels
    - - lacrimal and salivary glands, bone, teeth roots, other nerves and vessels