Retinal Detachment

Retinal breaks/degenerations

A full thickness defect in the neurosensory layer of the retina

• Holes

  • Atrophic: not associated with vitreoretinal traction, therefore no increased risk of retinal detachment
  • Operculated: less risk compared to HST, but may be treated with laser if the patient is symptomatic, persistent traction, superior or large holes.

• Tears

  • Horseshoe/flap: high incidence of progression to retinal detachment. Almost universal vitreous traction along the edge of the flap
  • Giant retinal tear: greater than 3 clock hours circumferentially, developing from vitreous base or lattice degeneration

• Dialysis:

  • Break originating from the ora. Vitreous base is attached. 10% of RRDs.

• Lattice degeneration: area of retinal thinning due to discontinuity of ILM with crossing white lines and small round holes. Associated with Stickler’s, Marfan’s, Ehlers-Danlos. Not treated prophylactically unless risk factors (see below)

• White-without-pressure: may be treated if fellow eye has had a GRT

• Retinoschisis: may be treated if double layer break

• Benign degenerations:

  • Retinal hyperplasia
  • Microcystoid change
  • Honeycomb/reticular degeneration
  • Snowflake degeneration
  • Pavingstone degeneration
  • Peripheral drusen
  • Pars plana cyst

Indications to treat a retinal break

• Symptomatic
• Subclinical RD
• Horseshoe tear (ie. U-shaped)
• Large tear
• Location: superotemporal/posterior
• Only eye or fellow eye with previous RD
• High myope
• Vitreoretinopathy or systemic risk factor such as Marfan’s/Stickler’s

Other rules/guidelines

• Inferior detachments with equal height on both sides: break is likely at 6 o’clock

Retinoschisis

• Splitting of the retina
• Degenerative retinoschisis:

  • More common in hypermetropes

  • Typically bilateral (50-80%)

  • Senile form (most common): split in the outer plexiform layer/inner nuclear junction

  • Reticular (less common) form: split in the nerve fibre layer, similar to X-linked juvenile retinoschisis

    • More likely to develop retinal detachment

  • Both inner and outer leaf breaks are needed for secondary RD to occur

Clinical features

• Asymptomatic unless very posterior extension
• Absolute field defect (compared to relative for RRD)
• Usually found inferotemporally (in 72%)
• Laser reaction (cp. Retinal detachment)
• Smooth surface with absent pigments

Complications

• Inner leaf breaks
• Outer leaf breaks
• Retinal detachment:
  • Low risk type due to outer leaf break only
  • High risk rhegmatogenous type: both inner and outer leaf break with full thickness retinal elevation

Retinal detachment types

Rhegmatogenous

• Associated with retinal breaks
• Corrugated surface
• Pigment and/or blood in vitreous
• Static fluid

Exudative

• No breaks
• Smooth surface
• Inflammatory cells may be present in vitreous
• Shifting fluid

Tractional

• Preretinal fibrosis (no breaks)
• Smooth surface
• Clear vitreous
• Minimal or no fluid

Proliferative vitreoretinopathy (PVR)

• RPE cells migrate into vitreous through a retinal break

• Convert to myofibroblasts and release transforming growth factor

• Fibrosis and contracture occur leading to tractional RD

• Risk factors

  • Multiple or large breaks
  • Vitreous haemorrhage
  • Recurrent detachment
  • Excessive cryotherapy or laser treatment
  • Silicone oil
  • Iris trauma

Retina society classification (1991)

• A: vitreous haze and pigment clumps
• B: retinal wrinkling, rolled edges, stiffness and vessel tortuosity
• C (multiple sub-classes): subretinal strands

Management

• Surgery +/- pharmacological adjuncts (5-FU).

• Early surgery if macula preserved to protect vision

• Silicone Study (1992)

  • Compared silicone oil vs gas for PVR associated with RRD
  • Oil was more effective than SF6 gas, but equal to C3F8.

Retinal detachment surgery

Overarching principles

• Identify all breaks: can begin preoperatively, informed by Lincoff’s rules
• Seal breaks: cryotherapy or laser
• Drain subretinal fluid: not always necessary as long as break and traction addressed
• Relieve vitreoretinal traction: buckle, vitrectomy, or pneumatic retinopexy

Cryotherapy

• Freezing treatment (probe is between -40 and -70) turns water to ice causing cell death

• Sterile inflammatory reaction

• Retinal adherence fully develops over 2 weeks (note: retinopexy is faster)

• Indications

  • To seal retinal breaks, especially where laser difficult due to

    • Small pupil
    • Far-peripheral retina
    • Media opacity

  • To treat pathological blood vessels eg. Coat’s or proliferative DM

    • Similar indications to above

  • Cyclodestruction (ciliary body) in glaucoma

  • Certain lid or intraocular tumours

• Complications

  • Pain
  • Conjunctival fibrosis: risk of bleb failure in trab patients
  • Inflammation: vitritis, CMO
  • PVR
  • Muscle injury
  • Scleral damage/necrosis
  • Epiretinal membrane

Scleral buckles

• Types

  • Placement

    • Radial
    • Segmental
    • Encircling

  • Material

    • Silicone
    • Hydrogels: more expensive and not used due to risk of complications
    • Gelatin: temporary

• Indications

  • Radial buckles: large U-shaped tear or posterior breaks
  • Segmental buckles: multiple breaks
  • Encircling band: breaks over >two quadrants, complex RD, mild PVR, previous failed segmental buckle

• Complications

  • Intraoperative: perforation, muscle damage, fish-mouthing, remaining break
  • Early: anterior segment ischaemia, angle closure, re-detachment, endophthalmitis, vitritis (from cryotherapy)
  • Late: extrusion/exposure or buckle infection, epiretinal membrane, PVR, diplopia, glaucoma

Vitrectomy

• Indications

  • RRD (uncomplicated and certain complicated cases)

    • RD with vitreous haemorrhage
    • Severe PVR
    • Giant retinal tear

  • Tractional RD

  • Advanced diabetic retinopathy

  • Trauma with intraocular foreign body

  • Epiretinal membrane

  • Macular hole

  • Post-operative endophthalmitis

  • Dropped nucleus

  • Aqueous misdirection

  • Diagnostic: chronic inflammation

• Complications

  • Intraoperative

    • Iatrogenic break
    • Vitreous haemorrhage
    • Suprachoroidal haemorrhage
    • Lens trauma

  • Postoperative

    • Vitreous haemorrhage
    • Choroidal haemorrahge
    • PVR
    • Recurrent detachment
    • Glaucoma
    • Cataract: almost inevitable
    • Band keratopathy
    • Endophthalmitis

• Intraocular gases

  • Uses:

    • Vitreous replacement after vitrectomy since they are optically clear, inert and highly buoyant (provide greater force than silicone oil).
    • Retinal tamponade eg. pneumoretinopexy

  • Non-expansile: air, nitrogen, helium

  • Expansile:

    • SF6: persists for 2 weeks. Expansion volume is x2 (nonexpansile concentration is 20%)
    • C2F6: persists for 3 weeks. Expansion volume is x3 (nonexpansile concentration is 18%)
    • C3F8: persists for 6-8 weeks. Expansion volume is x4 (nonexpansile concentration is 15%)

  • Silicone oil

    • Has similar properties to gases however may emulsify due to lower surface tension. Heavy oil can be used for inferior detachments (heavier than water)

    • Uses

      • Longer lasting volume replacement eg. PVR, GRT, control of vitreous haemorrhage (longer lasting tamponade), patients who cannot posture

    • Provides better immediate post-operative vision

    • Complications

      • Glaucoma
        • Angle closure from pupil block (iridectomy usually needed inferiorly)
        • Open angle from emulsified oil
      • Cataract
      • Band keratopathy
      • Inflammatory reaction to oil: uveitis, retinal toxicity
      • Epiretinal membrane
      • Recurrent detachment

Pneumoretinopexy

• Tamponade of break with intravitreal expansile gas
• Indicated for superior breaks only
• Avoids need for admission or complications of other procedures
• However may fail and carry risks of CRAO, gas migration, and new breaks

X-linked juvenile retinoschisis

• XLRS1 gene
• Abnormal intercellular adhesion molecule leading to retinal splitting at the NFL
• Poor visual prognosis: presents in early childhood with stellate/cystoid maculopathy which progresses to a macular scar
• Foveal schisis with spoke-like folds
• Non-specific atrophy
• Vitreous haemorrhage
• Retinal detachment in 5%
• Associated with hypermetropia
• Electronegative ERG: reduced b wave
• No systemic findings

Stickler’s syndrome

• Autosomal dominant abnormality of type II collagen production (COL2A1)

  • An autosomal recessive form is also recognised

• Aka ‘hereditary arthro-ophthalmopathy’

• Ocular features

  • Myopia
  • Empty vitreous
  • Lattice-like pigmentary perivascular changes
  • Strabismus
  • Retinal tears, giant retinal tears and retinal detachment
  • Cataract: comma-shaped cortical opacities
  • Ectopia lentis
  • Open angle glaucoma

• Systemic

  • Epiphyseal dysplasia: degeneration of large joints
  • Cleft palate
  • Abnormal uvula (bifid)
  • Mid-facial flattening
  • Pierre-Robin sequence: micrognathia, glossoptosis
  • Sensorineural deafness
  • Mitral valve prolapse
  • Marfanoid habitus

• Clinical diagnosis with molecular genetic testing

• Management

  • Prophylactic retinopexy for extensive lattice
  • Refractive correction for myopia to avoid amblyopia

Wagner syndrome

• Autosomal dominant vitreoretinopathy
• Optically empty vitreous
• Myopia
• Retinal detachment