vitreoretinal Flashcards
what is peripheral retinal degeneration
These are abnormalities in the peripheral retina.
examples
lattice degeneration
degenerative retinoschisis
what is lattice degeneration and its characteristics
more common in
These describe areas of thinning in the neurosensory retina (NSR) with overlying vitreous liquefaction and vitreoretinal adhesions, characterized by circumferential zigzag white lines with oval holes within the lesion.
more common in myopic eyes
30% of patients with acute rhegmatogenous retinal detachment (RRD) have lattice degenerations
which degeneration predisposes you to retinal tears
lattice
prophylatic Mx of lattice degeneration what is it and when should it be offered
only be offered to those patients with a retinal detachment (RD) in the contralateral eye, in the form of laser retinopexy.
what is degenerative retinoschisis
seen usually where
microcystic degeneration resulting in the splitting of the retinal layers between the outer plexiform and inner nuclear layers, usually inferotemporally.
features of degenerative retinoschisis
● Smooth convex and immobile elevation of retina with no demarcation line of chronicity as with RRD.
● Associated with absolute field defect.
mostly bilateral adn symmetrical condition
more common in hypermetropic eyes
what is posterior viterous detachment
why does it occur
Posterior vitreous detachment (PVD) is the separation of the posterior vitreous cortex from the NSR.
occurs with increasing age ->vitreous becomes more liquefied (synchysis) -> creation of empty pockets of fluid within the vitreous, leading to vitreous collapse (syneresis). Eventually fluid escapes in the retrovitreous space separating the posterior hyaloid from the NSR
features of posterior vitreous detachment
● Photopsia (light flashes) with associated floaters. VA usually not affected.
● Weiss ring: Thickened vitreous avulsed from optic disc.
● Shafer sign (pigmented particles or ‘tobacco dust’ in the anterior vitreous)
negative.
Mx of posterior vitreous detachment
Warn about risk of RRD and advise on presenting immediately if symptoms worsen or visual field affected.
● If complicated with retinal tear, treat with laser or cryoretinopexy.
high risks of Retinal detachment
● High myopia >6D ● Aphakia ● Giant retinal tear ● Symptomatic U-shaped retinal tear ● Systemic disease (e.g. Stickler syndrome)
what is a retinal tear
ass w
features
Mx
U-shaped defect due to anterior vitreoretinal traction on a strip of retina due to PVD
associated with vitreoretinal adhesions such as at the margins of lattice degenerations.
flashes, floaters, Weiss ring and Shafer sign positive
symptomatic U-shaped retinal tears should be treated with laser retinopexy.
what is giant retinal tear
Location of tear
ass w
retinal tear extending ≥3 clock hours (≥90°).
Location: Peripheral retina at posterior border of vitreous.
Associated with PVD, as are retinal tears. trauma, high myopia, diseases (e.g. Marfan or Stickler syndrome).
Mx
laser retinopexy for both eyes.
what is retinal dialysis
mx
A disinsertion of the retina at the ora serrata involving anterior and posterior to the vitreous base. Traumatic retinal dialysis is more common and located superonasally.
Idiopathic dialysis is more commonly located inferotemporally. Retinal dialysis is the leading cause of traumatic RD in children and young adults. Management is with laser retinopexy if there is no associated RD, otherwise scleral buckle is used.
what is retinal detachment
types of retinal detachment
separation of the NSR from the RPE. -> subsequent shift of subretinal fluid (SRF), called shifting SRF, in the space between the NSR and the RPE.
Three main types of retinal detachment exist: RRD, tractional RD and exudative RD.
what is rhegmatogenous retinal detachment
most common form of retinal detachment and occurs due to a retinal break. Fluid seeps in between the NSR and RPE causing a detachment
This is an emergency – it can lead to blindness if left untreated.
features of rhegmatogenous retinal detachment
● Flashes and floater.
● Curtain-like visual field loss (relative field loss).
● dVA if macula is involved.
● RAPD, Weiss ring and Shafer sign.
● Presence of PVD and retinal breaks (commonly a U-shaped retinal tear;
most common location is superotemporal).
features of fresh RRD
● Fresh RRD
- Convex and corrugated dome-shaped surface with loss of RPE markings
- Shape based on most superior retinal break.
- Extend from ora serrata to optic disc.
- They are progressive and may affect macula.
features of chronic RRD
Retinal thinning. Demarcation lines. Intraretinal cysts.
Proliferative vitreoretinopathy.
Ix for rhegmatogenous RD
Mx
● Slit lamp biomicroscopy with wide-field lens.
● Indirect ophthalmoscopy with scleral depression to visualise the ora serrata.
● B-scan USS if there is no view of posterior pole such as dense cataract or
vitreous haemorrhage.
Mx
● Vitrectomy: Most commonly used procedure, indicated for posterior retinal breaks, giant retinal tears and proliferative vitreoretinopathy.
● Scleral buckle: Very high success rate. Used in simple RRD and retinal dialysis when there is no pre-existing PVD.
● Pneumatic retinopexy: Lower success rate but also fewer side effects; used in carefully selected cases with small superior breaks 1 clock hour apart between 11 and 1 clock hours.
what us tractional retinal detachment
retina pulled off by membranes
vitreoretinal traction. This is an insidious process where fibrovascular membranes cause progressive contracture over areas of adhesions eventually causing a detachment. The most common causes are advanced proliferative diabetic retinopathy and ROP.
- Diabetic retinopathy
- Retinopathy of prematurity • Sickle cell retinopathy
features of tractional retinal detachment
Mx
● Usually asymptomatic (no flashes or floaters), as there is no PVD.
● VA affected once macula is threatened, causing distortion of vision.
● Detachment: Shallow immobile concave tenting of retina.
● Minimal shifting SRF.
● Associated relative visual field loss, signs of underlying disease.
● Vitrectomy with membrane peel.
