Retinal dettachment Flashcards
what is retinal detachment
seperation og neurosensory retina from the retinal pigmented epithelium (RPE) by sub retinal fluid (SRF)
a detached retina is sight threatening and can lead to blindness if not treated
how does retinal detachment begin
Detachment often begins in the thinner, peripheral retina & gradually extends to thicker more central areas
Majority caused by hole or tear through which SRF leaks
Patient may perceive new floaters and flashes
Patient often perceives a shadow that encroaches from peripheral vision
?Which tests can be useful? in diagnosing retinal dettachemnt
vf, fundus imaging and oct imaging
if retinal dettachemnt is left untreated what can it lead to
if left untreated can cause blindness
describe the epidemiology of retinal detachment
cPrevalence is approx. 1 in 10,000 annually (1 in 300 lifetime risk) however, ethnic variation is present (Mirty et al. 2010)
Asian populations at higher risk of RD compared to other ethnicities (Mirty et al. 2010)
Due to myopia
what are the signs and symptoms of retinal dettachment
Sudden appearance of floaters
Blurred vision or painless loss of vision
Photopsia - flashes of light in one or both eyes
Reduction in peripheral vision (gradual or sudden)
A shadow appearing over the visual field
what are the three main types of retinal dettachment
RD, Tractional RD, EXCUDATIVE RD
what is RD retinal dettachment
Rhegmatogenous RD – most common Reg-mah-toj-e-nus
Sub-retinal fluid (SRF) from the vitreous, gains access to the sub-retinal space through a retinal break / tear / hole
what is tractional retinal dettachemnt
Tractional RD
Fibro-vascular tissue, caused by injury, inflammation or neovascularisation, pulls the sensory retina away from the RPE
what is exudative rd
least common
No tear in retina. SRF from choroid gains access to the sub-retinal space through damaged RPE - often results from injury, inflammation, tumour or vascular abnormalities
what is the most common type of retinal dettachment
Rhegmatogenous RD
Rhegma means break. By far the most common. Patients report photopsia (presence of perceived flashes of light), floaters, peripheral vision loss, central blurred vision.
what are the causative factors of retinal dettachment
High myopia (over 5-6DS) greater axial length therefore retina stretched and thinner. – increases risk of retinal dettachment
-1 to -3DS 4x risk of RD than non-myopic eye
>3DS 10x risk of RD than non-myopic eye
(Eye Disease Case control study group, 1993)
Aphakia or pseudophakia 20-40% of rhegmatogenous RDs occur in eyes that have undergone cataract extraction. Predisposes patient to posterior vitreous detachment (Ramos et al, 2002).
Trauma: Shukla et al ( 1986) 11% due to trauma. Gradual onset: 50% presented over 1 month after incident.
what are other causative factors of retinal detachment
Dislocated lens
Blunt trauma
Penetrating ocular injury
Proliferative diabetic retinopathy (tractional RD)
Proliferative retinopathy of sickle cell disease
Intra-ocular foreign body (e.g. choroidal tumours)
Inflammation
Family history of RD
Systemic conditions (e.g. Marfan’s syndrome)
Vitreous haemorrhage following birth trauma / shaken baby syndrome
Bungee jumping (Curtis & Collin, 1999; Filipe et al, 1995)
Exudative RD associated with pregnancy pre-eclampsia
bungee jumping (due to the pressure) and also
Pre-eclampsia - is a problem with the placenta – results in high blood pressure with protein leaks from the kidneys into the urine
what are the aims of retinal dettachment surgery
Aim of Surgery
Seal the holes or areas of detachment by creating contact between the choroid & retina – PRESERVE VISION!
Multiple Procedures:
Pneumatic retinopexy
Cryotherapy
Laser photocoagulation
Scleral buckling
Pars plana vitrectomy
describe the processes of retinal detachment procedures
Cryotherapy involves using a cryoprobe which freezes to -80 degrees. It is placed on the sclera and freezes the choroid to the retina and induce an inflammatory lesion that on scarring produce a very strong bond b/w sensory retina and RPE which seal the retinal break permanently
Laser
photocoagulation is the opposite to cryotherapy rather than freeze, several burns (heat) are placed around the retinal hole
The principle of
scleral buckling is to create an inward indentation of the sclera i.e. produce a ‘buckle’. The aims of scleral buckling are:
To close the retinal break/hole by apposing the RPE and sensory retina, and release vitreo-retinal traction
Pars plana
vitrectomy my be considered in cases with tractional RD, rhegmatogeneous RD with Giant tears or macular holes.
It is a microsurgical procedure, in which the surgeon inserts the instrument through v small holes in the pars plana into the vitreous cavity
what procedure is done when retinal dettachemnt is superior
pneumatic retinopexy
gas bubble is injected into the patients eye
Patient’s head positioned so that bubble floats upwards to rest against the RD
what is cryotherapy
A cryoprobe freezes to -80°. Placed on the sclera at position of the RD
Freezes choroid to retina to induce an inflammatory lesion
Scar tissue produces very strong bond between sensory retina and RPE which seals the retinal break permanently
what is laser photocaogaulation
used when there is a small tear or retinal dettachment is slight
opposite to cryotherapy - rather than freeze
several burns (heat) are placed around the retinal hole
what is pars plan vitrectomy
Used with tractional & rhegmatogenous RD & with giant tears or macular holes
Microsurgical procedure
Instruments inserted through very small holes in pars plana into vitreous cavity
Vitreous humour removed
Removes bloodied or clouded vitreous
what is scleral buckling
Principle to indent sclera
Piece of silicone plastic or sponge is sewn onto the sclera at the site of the retinal tear to push sclera towards the retinal tear
Buckle holds retina against the sclera until scarring seals the tear.
what are the types of scleral buckling
There a different types of scleral buckling. There is local buckling explant which is created by using either a soft silicone sponge or a hard silicone tyre.
A radial explant is placed at right angle to the limbus (from back to front of the eye).
A circumferential explant is placed circumferential to the limbus (around the eye) and creates a segmental buckle which can be of different lengths. It may have to be placed under the EOM’s.
what is the aim of treatment of retinal detachments
Aim: seal the holes or areas of detachment by creating contact between the choroid & retina – PRESERVE VISION
Treatment method differs based on patient’s needs
Overall success rate between 80-90% after one procedure (Sultan et al, 2021)
Patient can have multiple procedures if required
what are the potential issues post treatment
Aniseikonia – different image sizes perceived from each eye due to unequal magnification
what are all the potential issues post treatment
Myopic shift common after scleral buckle (Nassaralla, 2003)
Ocular motility disturbances
Torsion
Loss of fusion
Loss of or poor VA due to RD
Distorted vision due to macular changes
Aniseikonia – different image sizes perceived from each eye due to unequal magnification
Induced myopia, astigmatism and/or anisometropia by the scleral buckle
Decompensated heterophoria
what are causes of motility imbalance after retinal detachment surgery
Mechanical- due to disinsertion of the muscle
Paralytic (trauma to nerve)
Myogenic (trauma to muscle)
Secondary strabismus
what are the mechanical problems after retina al detachment surgery caused by
The muscle may be disinserted from the globe by excessive traction resulting in the muscle may be lost
Placing an explant beneath the muscle alteration of the muscle action. This may also result in Stretching of the EOM which can cause fibrotic changes and secondary restriction
The bulk of the explant interference of globe rotation
Anterior migration of scleral buckle identified on MRI scans. This may be due to swelling of the explant in some patients causing large incomitant deviations and diplopia
Post-operative inflammation result in swelling within the orbit and result in mechanical limitations of OM
Re-attachment surgery is likely to cause scarring which can result in adhesions b/w EOM’s, b/w an EOM and the globe, connective tissues, sclera or a component of the scleral buckle
Wright in 1986 proposed that the Fat adhesion syndrome plays an important role in causing restrictions.
Retinal re-attachment surgery involves piercing Tenon’s capsule. This allows orbital fat to come in contact with EOM’s and/or the globe and induces fibrosis that results in scarring and adhesions b/w these tissues followed by contraction.
Fat adherence occurs most frequently occurs at the EOM sleves during RD surgery. As scarring and contraction of tissues happen it may result in progressive strabismus.
what is anieskonnia
different image sizes perceived from each eye due tp unequal magnification
what are factors that increase the incidence of motility imbalance and diplopia
No of procedures
Size of the explant
Encircling scleral buckle
Poor VA
Macula detached
why can strabismus and diplopia occur after surgery
Poor VA results in poor fusion which may lead to secondary strabismus c/s diplopia
If the macula is detached it generally results in poorer vision and poorer fusion
is spontaneous improvement likely in these patients
Many of the patients report improvement of symptoms with time
Immediately post-op many have reduced VA due to the detachment which often improves. As VA improves will improve the ability for fusion and the strabismus resolves
A reduction in swelling will reduce the limitations of eye movements
The strabismus may be transient and resolve with time
patient may learn to suppress the 2nd image
what needs to be done in an orthoptic investigation
Important to take a detailed history of any pre-existing strabismus/diplopia prior to RD surgery.
? congenital SO palsy or longstanding vertical deviation or compensated vertical deviation
If any prisms incorporated into glasses?
Full investigation is imperative!
History
? pre-existing deviation
Symptoms
– Onset / severity
Diplopia
Distortion
Aniseikonia
Glare
Myopic shift
Colour vision
Alignment
Psycho-social
what tests need to be done in an orthoptic investigation
VA
CT
OM
Saccades – may be slow
Binocular function
Sensory fusion
Motor fusion
Stereoacuity
Measure angle of dev
Serial Hess Charts
? Field of BSV
? Field of Unioc Fix
Imaging – Fundus photos or OCT
what are the aims of investigtton
? Monocular or binocular diplopia
? Potential for BSV
Is the motility imbalance
Mechanical
Neurogenic
Myogenic
what are the management options
Observe for a minimum of 6 months after the RD surgery to monitor any improvement or deteroriation
It is important to carry out a refraction as astigmatism may have been induced
You can teach the patient how to adopt a compensatory head posture, although most will have adopted it themselves to obtain BSV
Give prisms, fresnel as they are a temporary mean which you can incorporate if stable
Occlusion
-blenderm
-bangert filter to teach them to suppres 2nd image
-occlusive CL
-frosted lens
how can patients be managed with botulinum toxin
BT-injection
(Scott, 1990; Lee et al. 1991; Maurino et al. 1998; Dawson et al. 2005)
Inject the rectus muscle (MR, LR, & IR)
They recommend injecting the rectus muscles in the affected eye, but not the SR because it may result in ptosis
When is BT valuable?
Assess potential for BSV
Repeat injections to regain BSV
Repeat injections for psycho-social problems
High risk of re-detachment or explant extrusion if perform strabismus surgery
Avoid GA
when is the use of botulinum toxin contraindicated
Contra-indicated for hypertropia (SR botox migrates to LPS-)
Complications
induce vertical deviation (with diplopia) when inject horizontal muscles
Ptosis
Subconjunctival hemorrhage
*No severe complication such as re-detachment, extrusion of explant, scleral perforation or orbital hemorrhage was induced by BT injection (Scott, 1990; Lee et al. 1991)
how can patients be managed using strabismus surgery
Difficult
Due to Scarring & fibrosis post RD surgery
Risk of re-detachment & explant extrusion
High-resolution MRI at multiple positions may help (Wu et al. 2005)
Surgical technique
FDT
Free the fat adhesions and restore normal anatomy
Possibly removal of buckle
Strabismus SX
what is the cause of retinal dettachement in strabismus surgery
Vitreous hemorrhage may lead to retinal detachment following birth trauma or shaken baby syndrome. Early surgery is advocated to prevent the development of amblyopia. The development of strabismus particularly esotropia is common
what is retinal dettachment
When the neurosensory retina comes away from the retinal pigment epithelium
A sight threatening condition which can cause blindness if untreated
what are the three main types of retinal dettachment and which one is the most common
Rhegmatogenous RD – most common Reg-mah-toj-e-nus
Tractional RD
Exudative RD – least common
rhegmatogenous is the most common
What imaging techniques could be useful for the detection of a retinal detachment?
If a patient has a superior retinal detachment (15%) what treatment method would be most useful?
pneumatic retinopexy
