Pathology of the retina and choroid Flashcards
What is pathologic myopia?
Type of myopia that begins during childhood and progressively worsens, resulting in severe myopia by adulthood with an axial length >/= 26mm or refractive error >/= -6.00D)
What are some factors that can cause pathologic myopia?
- Environmental and genetic influences cause increased axial growth of the eyeball
- Often accompanied by degenerative changes in the retina
How does pathologic myopia present?
- Blurred vision
- Scleral thinning
What will fundoscopy show in pathologic myopia?
- Lacquer cracks
- Subretinal haemorrhage
- Fuschs’ spot - degeneration of the macula; occurs due to proliferation of RPE associated with choroidal haemorrhage
- Posterior staphyloma - outpouching of scleral tissue typically involving the optic disc or macula
- RPE/choroid atrophy
- Degeneration - cystoid, paving stone, lattice
What is shown?
Pathologic myopia
What is shown?
Pathologic myopia - Evaluates development of choroidal neovascularisation
How is pathologic myopia managed?
- Annual checkups if stable
- If CNV develops - anti-VEGF
What are some causes of retinal tears?
- Age-related degeneration of the retina
- Myopia
- Eye injuries
- Eye surgery e.g. cataract
What is a retinal hole?
An area of progressive thinning of the retina due to chronic retinal atrophy
What is a retinal break?
A full thickness defect in the sensory retina; when a retinal break is associated with vitreous traction (PVD), it is termed a retinal tear
How does retinal tear present?
- Asymptomatic
- May have photopsia or see floaters
How are retinal tears managed?
- Management ofretinal tearsaims to create adhesions between the retina and the choroid to prevent detachment
- This can be done using laser therapy or cryotherapy
What is a possible complication of retinal tear?
Retinal detachment
What is retinal detachment?
Refers to the detachment of the inner layer of the retina from the retinal pigment epithelium
What are the 2 forms of retinal detachment?
Rhegomatogenous
Non-rhegomatogenous
What is a rhegmatogenous retinal detachment?
Detachment of the retina caused by a tear or hole, with acute posterior vitreous detachment and predisposing peripheral retinal degeneration
What are some risk factors of rhegmatogenous retinal detachment?
- Posterior vitreous detachment
- Pathological myopia
- Previous intraocular surgery
- Trauma
What is non-rhegmatogenous retinal detachment?
Detachment without any retinal tears
What are the 2 forms of non-rhegmatogenous retinal detachment?
Tractional
Exudative
Describe the pathophysiology of tractional retinal detachment
- Formation of vitreoretinal bands (most commonly due to proliferative diabetic retinopathy)
- Pressure on the band during eye movement or as a result of sudden decrease in intraocular pressure
- Retinal detachment
Describe the pathophysiology of exudative retinal detachment
Subretinal fluid accumulation without retinal tears
What are some causes of non-rhegmatogenous retinal detachment?
- Choroidal tumours - primary or metastatic
- Intraocular inflammation - Harada disease, posterior scleritis
- Systemic - toxaemia of pregnancy, hypoproteinaemia
- Iatrogenic - RD surgery, excessive retinal photocoagulation
- Miscellaneous - choroidal neovascularisation, uveal effusion sydrome
What are some symptoms of retinal detachment?
- Painless, progressive visual field loss
- Patients may describe a curtain/shadow descending or ascending on field of vision
- Shadow corresponds to area of detached retina
- If detachment affects macula, central vision will be lost
- Sudden onset of floaters/flashes can preceed visual loss - indicates posterior vitreal detachment
What is a possible sign of retinal detachment?
RAPD
What are some signs of rhegmatogenous retinal detachment on fundoscopy?
- Retinal tear may be visible
- Detatched retina takes a convex shape
- Deep mobile elevation extending to ora serrata (junction between retina and ciliary body)
- Slightly opaque with dark blood vessels
- Loss of choroidal pattern
What are some signs of non-rhegmatogenous retinal detachment on fundoscopy?
- Detatched retina takes a convex shape
- Smooth elevation
- May be very mobile deep with shifting fluid
- Subretinal pigment (leopard spots) after flattening
- No retinal tear visible
What is shown?
Rhegmatogenous retinal detachment
What is shown?
Non-rhegmatogenous retinal detachment
How is retinal detachment managed?
Various surgical options which aim to reattach the retina and reduce any traction or pressure that may cause it to detach again
What is posterior vitreous detachment?
Detachment of the posterior vitreous cortex from the internal limiting membrane of the retina
What are some causes of posterior vitreous detachment?
- Age-related degeneration of the vitreous body (most common cause)
- Myopia
- Eye injury
How does posterior vitreous detachment present?
- Usually asymptomatic
- Photopsia with eye movements - caused by partially detached vitreous tissue pulling on the retina
- Floaters - collection of deposits in the vitreous body of the retina perceived as spots or strings drifting through the visual field
What is shown?
Posterior vitreous detachment
What is shown?
Posterior vitreous detachment
How is posterior vitreous detachment managed?
No treatment necessary - symptoms improve as brain adjusts
What is a possible complication of posterior vitreous detachment?
Can predispose to patients developing retinal tears and retinal detachment
What is vitreomacular traction?
Incomplete posterior vitreous detachment with the persistently adherent vitreous exerting tractional pull on the macula and resulting in morphologic alterations and consequent decline of visual function
How does vitreomacular traction present?
- Metamorphopsia
- Decreased vision
What investigation is required in vitreomacular traction?
Optical coherence tomography (OCT)
How is vitreomacular traction managed?
Options include observation, surgical management and medical therapy
What is central serous chorioretinopathy?
Serous retinal detachment at the posterior pole of the eyeball (macula or perimacular region) due to a defect in the pigment epithelium which allows fluid to leak from the sclera into the subretinal space
Who is most commonly affected by central serous chorioretinopathy?
Men 30-50 years old
How does central serous chorioretinopathy present?
- Hyperopia
- Metamorphopsia
How will central serous chorioretinopathy present on fundoscopy?
Roundish detachment of central retina
What is shown?
Central serous chorioretinopathy
How will central serous chorioretinopathy present on fluorescein angiography?
Most common finding is a small, focal hyperfluorescent RPE leak
What is shown?
Central serous chorioretinopathy - Most common finding is a small, focal hyperfluorescent RPE leak
What is epiretinal membrane?
Scar tissue formation across the inner surface of the retina which can cause visual problems
What causes epiretinal membrane?
- Scar tissue most commonly forms due to age-related vitreous retraction
- Can also form following eye surgery or inflammation inside the eye
How does epiretinal membrane present?
- Metamorphopsia
- Decreased acuity
How will epiretinal membrane present on fundoscopy?
- Retinal striae
- Subretinal fluid or cystic damage
- Almost always associated with PVD
What is shown?
Epiretinal membrane
How is epiretinal membrane managed?
Surgery indicated if patient has significant visual complaints of visual decline and /or metamorphopsia
What is a macular hole?
Central small break in the macula
What are some causes of macular hole?
- Idiopathic
- Secondary e.g. due to vitreous detachment, trauma
How will macular hole present?
- Metamorphopsia
- Central visual field losses
- Severe reduction of visual acuity
How will macular hole present on fundoscopy?
- Depending on the stage, a subfoveal spot or ring can be noted
- In more advanced cases, a partial or full-thickness macular break is observed
What is shown?
Macular hole
How is macular hole managed?
There are conservative, medical and surgical options depending on the stage of the hole
What is cystoid macular oedema?
Retinal thickening of the macula due to accumulation of fluid in the outer plexiform layer
What are some causes of cystoid macular oedema?
- Postoperative
- Uveitis
- Retinal venous occlusive disease
- Choroidal neovascularisation
- Epiretinal membrane /VMT
- Retinitis pigmentosa
How does cystoid macular oedema present?
Blurred/decreased central vision
How is cystoid macular oedema managed?
Majority (95%) of cases spontaneously resolve
What is chorioretinitis?
Inflammatory and exudative condition of the choroid and the retina (form of posterior uveitis)
What are some causes of chorioretinitis?
- Most often seen in immunodeficient patients e.g. HIV/AIDS
- Usually a response to viral, bacterial, fungal or protozoal infection
What are some forms of chorioretinitis?
Acute retinal necrosis
Endogenous chorioretinitis
Toxoplasma gondii
Ocular toxocaracanis
What causes acute retinal necrosis?
HSV/HZV
What causes endogenous chorioretinitis?
- 50% bacterial, 50% fungal e.g. candida
- Associated with bacterial endocarditis or indwelling catheters including central lines
What causes toxoplasma gondii chorioretinitis?
- Congenital or acquired
- Associated with contaminated soil and undercooked meat
How can toxoplasma gondii chorioretinitis present?
- Results in a mild flu-like illness and rarely causes any further problems
- In immunocompetent patients it enters latent phase with cysts forming, can reactivate
What causes ocular toxocaracanis (Roundworm)?
- Ingestion with toxocara eggs (parasite hosted by cats and dogs) leads to systemic and ocular infection
- Reactive inflammatory processes lead to the organism’s encapsulation and the formation of eosinophilic granulomas - can cause irreversible visual loss if the egg has migrated to the eye
- No proven treatment
What is shown?
Acute retinal necrosis
What is shown?
Endogenous chorioretinitis
What is shown?
Endogenous chorioretinitis
What is shown?
Toxoplasma gondii chorioretinitis
What is shown?
Ocular toxoxaracanis (Roundworm)
How will will older patients present with chorioretinitis?
- Older patients commonly present with reduced visual acuity with floaters
- Degree of symptoms depends on where the inflammatory lesions lie
- Symptoms are usually unilateral and tend to develop over several days
How will congenital chorioretinitis present?
Congenital infections may present insidiously, with little history and few symptoms
What investigations are required in chorioretinitis?
- Swab - culture (bacterial/viral), serology for toxoplasma and toxocara
- Serology for toxoplasma and toxocara
How is chorioretinitis managed?
May involve observation or antimicrobials ± topical steroid treatment - depends on causative pathogen and other criteria
How is toxoplasma gondii chorioretinitis managed?
Systemic treatment if sight-threatening (clindamicin/azithromycin +/- steroids)
What is the most common cause of blindness in individuals over 65 in developed countries?
Age-related macular degeneration
What is thought to be the cause of ARMD?
Not clear - age-related, underlying inflammatory process
What are some risk factors of ARMD?
- Increasing age
- Smoking
- Positive family history
- Poor nutrition
What are the 2 main types of ARMD?
Dry ARMD
Wet ARMD
Describe the pathophysiology dry ARMD?
Deposition of drusden (accumulation of byproducts - proteins, lipids, and inflammatory mediators) in RPE and between RPE and Bruch membrane results in slow progressive atrophy of the local RPE
How does dry ARMD present?
- Gradual decline in vision
- Central vision ‘missing’ (scotoma)
What is shown?
Scotoma (Central vision loss)
What will be seen on fundoscopy in dry ARMD?
- Drusen
- Atrophic patches of retina
What is shown?
Dry ARMD
How is dry ARMD managed?
- No cure - treatment is supportive with low vision aids e.g. magnifiers
- Magnifiers increase retinal image size, making object easier to see as scotoma stays the same size
Describe the pathophysiology of wet ARMD
- Neovascularisation in choroid, mediated by VEGF
- New vessels are small and fragile → more likely to haemorrhage so more likely to result in visual loss
How does wet ARMD present?
- Rapid central visual loss
- Distortion (metamorphopsia)
What will be shown on fundoscopy in wet ARMD?
Haemorrhage/Exudate
What will be shown on fluorescein angiography in wet ARMD?
What will be shown on OTC in wet ARMD?
How is wet ARMD managed?
Anti-VEGF
