WCS31 Common Eye Diseases Flashcards
Common eye diseases
- Inflammatory
- Conjunctivitis (Allergic, Viral, Bacterial)
- Pterygium (翼状胬肉)
- Stye (眼挑針)
- Chalazion (瞼板腺囊腫)
- Blepharitis (眼瞼炎)
- Dry eyes - Degenerative
- Cataract (age-related)
- Primary glaucoma
- Macular degeneration (age-related) - Miscellaneous
- Trichiasis
- Entropion
- Ectropion
Common eye diseases can co-exist!!!
—> e.g. Cataract with Diabetic retinopathy / Glaucoma
—> must find out real cause of impaired vision
Inflammatory eye diseases
Common features:
- Redness
- Discomfort
- Visual disturbance depending on tissue involved
- Conjunctivitis (Allergic, Viral, Bacterial)
- Pterygium (胬肉)
- Stye
- Chalazion
- Blepharitis
- Dry eyes
Allergic conjunctivitis
Symptoms:
- Bilateral usually
- **Lid: Swelling
- **Conjunctiva: Hyperaemia, Chemosis
- Hyperaemia
- Itchiness
- Water / mucus discharge
- Tearing
- Other allergy: Allergic rhinitis
Management:
- Avoid triggers
- Tears (e.g. Artificial tears)
- Topical **Anti-histamines
- Topical **Steroid
Viral conjunctivitis
Symptoms:
- Unilateral to Bilateral
- Infectious
- **Gritty sensation (foreign body sensation)
- **Diffuse conjunctival injection
- Serous discharge
- May involve cornea
- ***Absent of itchiness
Causative agents:
- ***Adenovirus (self-limiting)
Management:
- Symptomatic treatment: Tears, Topical Steroid (if cornea involved)
- Personal hygiene
Bacterial conjunctivitis
Symptoms:
- Conjunctival injection
- ***Sticky discharge, Pus
Causative agents:
- Staphylococcus
- Streptococcus
- Haemophilus
Management:
- Swab for culture
- Topical Antibiotics (***Chloramphenicol, Moxifloxacin)
Pterygium (胬肉)
***Thickening of conjunctiva
Causes:
1. **UV-light stimulation
2. Dry eyes
3. **Sandy environment
Symptoms:
- Affects vision when obscuring visual axis / inducing ***astigmatism
Management:
- Lubricant
- Avoid UV light
- Excision —> High rate recurrence
Stye
Acute bacterial infection of ***eyelash follicle
Symptoms:
- Sudden onset of lid swelling
- Painful
- Pus released when ruptured
Management:
- Warm compress, 3 times a day (SpC FM PP)
- Topical Antibiotics +/- Drainage
Chalazion
Blockage of meibomian gland in the tarsal plate
—> Accumulation of meibomian gland secretion (Cheesy material in a cyst)
Symptoms:
- Discomfort
- May cause ptosis
Management:
- **Self-limiting (within a few months)
- **Warm compress
- Steroid injection
- Incision + Curette
Blepharitis
Inflammation of eyelids from ***congested / dysfunctional meibomian oil glands at the base of each eyelash
Symptoms:
- Bilateral
- **Staphylococcus
- **Crusts + Scales on lid margins
- Swollen + Erythematous lid
- Excessive oily secretion
- Foam (fermentation of oily secretion)
Management:
- Lid hygiene
- Topical Antibiotic
- Tetracycline
Dry eyes
20-30% general population
3 layers of Tear:
1. Mucin
2. Aqueous (middle)
3. Lipid (outermost)
Defect in lipid layer (e.g. Blepharitis) —> evaporation of tears very quickly
At risk groups:
- Old age
- Contact lens wearer
- Post-LASIK
- Autoimmune diseases (attack lacrimal glands)
- Post-menopause
- Drugs (Atropine, Anti-histamines, Glaucoma eye drops)
Symptoms:
- Non-specific
- Foreign body, burning sensation
- Ocular pain
- Redness
- Photophobia
- Visual disturbance (on/off)
Investigations:
- **Schirmer’s test (measure amount of tear production)
- **Tear Break Up Time (TBUT) (determine stability of tear film and checking evaporative dry eye)
- Punctuate epithelial erosion (on/off pain, visual disturbance)
Management:
- Frequent lubricants (tears + gel)
- Topical **Steroid
- Topical **Cyclosporin
- ***Punctal occlusion (occlude punctum —> aqueous not drained away so easily)
- Environmental factors
- Frequent blinking
Degenerative eye diseases
Common features:
- Old-aged population
- Visual impairment
- **Asymptomatic in early stage
- **Slowly progressive
- Cataract (age-related)
- Primary glaucoma
- Macular degeneration (age-related)
Cataract (age-related)
Opacification of natural crystalline **lens
- ~100% occurrence in 70 yo
- **commonest cause of blindness worldwide
- treatable
Symptoms:
- Gradual deterioration of vision
- Early: affect quality of vision (e.g. glare)
- Late: affect visual acuity
- Complicated: **Acute angle closure (∵ enlarged lens), **Acute uveitis (∵ lens protein leakage)
Types (depending on location of change):
1. Cortical cataract (lens surface)
2. Nuclear sclerosis (lens centre)
3. Posterior sub-capsular
4. Mature
Management:
- Surgery
—> Emulsify cataract
—> Put in intraocular lens
—> Also correct pre-existing refractive error
Glaucoma
**Accelerated death of **retinal ganglion cells
—> Optic neuropathy with characteristic Optic nerve head + Visual field changes
- Optic nerve damage is irreversible
- 2nd commonest cause of blindness
Risk factors
- Raised IOP (but can be IOP independent!!!)
Raised IOP =/ Glaucoma
Types:
1. Primary Open Angle Glaucoma (POAG)
- ↑ resistance in tissue layer in trabecular meshwork —> obstruction in aqueous drainage —> accumulate in anterior chamber —> ↑ IOP
- Primary Angle Closure Glaucoma (PACG)
- majority chronic (only minority go through acute attack)
- mechanical obstruction of the trabecular meshwork by either apposition of the peripheral iris to the trabecular meshwork or by a synechial closed angle - Normal Tension Glaucoma (NTG)
- IOP plays a relatively minor role in nerve damage
(4. Secondary Glaucoma (open/closed angle)
- uveitic, steroid induced, neovascular)
(5. Congenital Glaucoma)
Symptoms:
1. Asymptomatic in early stage of disease (∵ only affect side vision)
2. **↑ Cup-Disc ratio
3. **Visual field defect
Investigations:
1. **Visual field
2. **Optical coherence tomography (OCT: measure nerve fibre layer thickness)
3. ***Fundoscopy
Management:
- ↓ IOP (even for NTG) (Individualised IOP target)
—> medications
—> laser
—> surgery
POAG vs PACG
Different treatment:
- PACG can be treated anatomically to widen angle
- POAG cannot be treated
Normal IOP
6-21 mmHg
