Key points 14 Flashcards
Hard exudates are found in which layer of the retina:
caused by underperfusion leading to damage to the endothelium of deep capillaries. This causes leakage of plasma into the outer plexiform layer.
Which landmark study evaluated the effect of tight blood pressure and blood sugar control on diabetic retinopathy in Type 1 diabetics?
DCCT
Which landmark study evaluated the effect of tight blood pressure and blood sugar control on diabetic retinopathy in Type 2 diabetics?
UKPDS
When is generally considered the optimal time for surgical repair of orbital floor fractures:
1 to 2 weeks post-injury provides a chance for orbital swelling and contusion diplopia to resolve and yet is early enough to avoid problems with scarring of a significant floor fracture.
The Early Vitrectomy Study (EVS) found that for patients with post-operative endophthalmitis an early vitrectomy leads to a better visual outcome compared to standard intravitreal antibiotics if the presenting vision is:
PL or worse early vitrectomy led to a three-fold increase in the number of these patients ultimately achieving 6/12 or better.
What are the features of Incontinentia pigmenti
X-linked dominant
skin lesions which evolve from blistering in newborn, to macular hyperpigmentation in childhood to linear hypopigmentation in adulthood
alopecia
hypodontia
neurological problems e.g. cerebral atrophy
ocular features include: vascular abnormalities in the peripheral retina including capillary non-perfusion, AV shunts, fibrovascular proliferation, and neovascularisation, which may progress to retinal detachment. It can also be associated with cataract and with combined harmatoma of the RPE and retina.
Structures visible on gonioscopy from anterior to posterior are:
Schwalbe’s line, non-pigmented trabecular meshwork, pigmented trabecular meshwork, scleral spur, ciliary body
The major immunoglobulin constituent in human tears is:
The major immunoglobulin class found in human tears is IgA. IgD has not been detected in any study of human tears.
Place the following retinal injuries in order of their frequency following blunt ocular injury (MOST frequent first):
- Tears around lattice
- Giant retinal tears
- Inferotemporal dialysis
- Superonasal dialysis
- Flap tears
inferotemporal dialysis
superonasal dialysis (contra-coup injury)
giant tear
flap tear
tear around lattice
For a patient to be reassured that systemic disease is unlikely, ocular myasthenia should remain localized for what length of time?
82% of patients who later developed generalized weakness did so in the first 2 years after diagnosis of ocular myasthenia.[2] Hence, patients who keep having strictly ocular symptoms for 2 or more years are unlikely to revert to the generalized aspect of the disease.
A patient is suffering from the following symptoms since commencing a recent medication: dry eyes, inflamed conjunctiva, corneal ulceration, mouth ulceration and target skin lesions.
What is the most likely drug?
The clinical features described are consistent with Stevens-Johnson syndrome, which can be caused by many drugs, including the sulpha antibiotics
What is the most common malignant tumour of the lacrimal sac
SCC
A brainstem lesion that involves the medial longitudinal fasciculus as well as the ipsilateral abducens nucleus will most likely cause:
A lesion of the abducens nucleus will often involve the nearby PPRF and result in an ipsilateral gaze paresis. A lesion that also disrupts the ipsilateral MLF will result in the combination of an ipsilateral gaze palsy and internuclear ophthalmoplegia. This combination has been termed the one-and-a-half syndrome. The only horizontal eye movement that remains is contralateral abduction.
Which muscles are affected most commonly in thyroid eye disease?
The order of involvement of ocular muscles in thyroid eye disease is (most common first):
inferior rectus
medial rectus
superior rectus
levator
lateral rectus
Oblique muscles are rarely involved in TED.
What are the causes of chronic follicular conjunctivitis?
trachoma (Chlamydia serotypes A to C)
adult inclusion conjunctivitis (Chlamydia serotypes D to K)
molloscum contagiosum
drug-induced (e.g. brimonidine)
bacterial: e.g. Parinaud’s oculoglandular syndrome/Cat scratch/Lyme
Axenfeld’s follicular conjunctivitis
Merril-Thygeson
rosacea blepharitis
The two most commonly encountered chemical compositions of band keratopathy are:
calcium
urate
Which feature is most helpful in differentiating between actinic keratosis and seborrheic keratosis:
Epithelial atypia is not a feature of seborrheic keratosis, but is present in actinic keratosis. Both lesions are characterised by hyperpigmentation and inflammation.
Which is most likely to cause orbital hyperostosis?
Orbital hyperostosis is thickening of the bony walls of the orbit. It may occur in benign osseous tumours, most commonly meningioma. It may also occur in malignant bone tumours such as osteosarcoma and in metastatic lesions as in prostate carcinoma.
According to Alexander’s law, in which position should upbeat nystagmus be most prominent?
Alexander’s law refers to the increased frequency and amplitude of nystagmus movements accompanying gaze in the direction of the fast-beating component. Downbeat nystagmus most frequently violates the law.
A 40-year-old patient with a chronic history of sinusitis presents with a 10-day history of worsening right-sided painful proptosis and chemosis. There is severe limitation of right eye movements in all directions and a right RAPD. Slit lamp examination reveals sclerokeratitis.
The findings are most in keeping with:
sclerokeratitis, orbital disease and co-existing sinus disease raise suspicion of Wegener’s.
A patient is diagnosed with normal tension glaucoma and prescribed latanoprost drops at night to both eyes. On routine review 3-month later, it is noted that he has reduced visual acuity in his right eye and visual field progression compared to the last visit bilaterally.
Which investigation is most important?
The differential of NTG must always include lesions of the visual pathway. A sudden progression of visual fields and loss of visual acuity are not consistent with glaucoma, and an alternative diagnosis should be sought urgently by arranging an MRI of the brain and orbits.
Acute idiopathic blind spot enlargement is considered a possible spectrum of which condition:
Acute idiopathic blind spot enlargement shares many features with MEWDS. These two conditions, along with acute macular neuroretinopathy, may represent spectra of the same disorder.
Presumed ocular histoplasmosis syndrome is most common in which geographic location:
Presumed ocular histoplasmosis syndrome is almost exclusively found in the United States, especially in the Midwest. This, despite the fact that the histoplasma capsulatum fungus is found throughout the world in river valleys.
The correct spot size for argon laser trabeculoplasty (ALT) is:
50-micron beam with variable power to produce blanching or a tiny bubble at the anterior pigmented edge of the trabecular meshwork. Typically 180 degrees is treated at one sitting. Outflow facility typically improves following successful ALT.
