DR SAMUEL PONRAJ

Rhegmatogenous Retinal detachment

Anatomy of Peripheral Retina

Pars planaOra serrata Normal variants - Dendate process - Oral bay -meridonial fold -enclosed oral bay -granular tissue

Peripheral –innocuous lesios: -microcystic degeneration - Pavingston degeneration -Honey comb degeneration - Drusen

Vitreous baseVitreous adhesions -normal -abnormal

It is characterized by the presence of a retinal break held open by vitreoretinal traction.

Rhegmatogenous (rhegma – break), occurs secondarily to a full-thickness defect in the sensory retina, which permits fluid derived from synchytic (liquefied) vitreous to gain access to the subretinal space.

Pathogenesis - Dynamic Vitreoretinal traction

liquefaction of the vitreous gel

hole in the posterior hyaloid membrane

Fluid tru defect into retrohyaloid space

vitreous gel collapsessynchytic fluid in

space

Detachment of posterior vitreous from

ILMAcute PVD

Symptoms

1    Photopsia is the subjective sensation of a flash of light. In eyes with acute PVD it is probably caused by traction at sites of vitreoretinal adhesion.

The cessation of photopsia is the result of either separation of the adhesion or complete tearing away of a piece of retina (operculum).

In PVD an arc of golden or white light induced by eye movements - in dim illumination. --patient's temporal peripheral visual field.

   2    Floaters are moving vitreous opacities which are perceived when they cast shadows on the retina. Vitreous opacities in eyes with acute PVD are of the following three types:   

a    Weiss ring is a solitary floater consisting of the detached annular attachment of vitreous to the margin of the optic disc

   b    Cobwebs are caused by condensation of collagen fibres within the collapsed vitreous cortex.

  c    A sudden shower of minute red-coloured or dark spots usually indicates vitreous haemorrhage secondary to tearing of a peripheral retinal blood vessel.

   3    A visual field defect is perceived as a ‘black curtain’. In some patients it may not be present on waking in the morning, due to spontaneous absorption of SRF while lying inactive overnight, only to reappear later in the day. A lower field defect is usually appreciated more quickly by the patient than an upper field defect. The quadrant of the visual field in which the field defect first appears is useful in predicting the location of the primary retinal break, which will be in the opposite quadrant. Loss of central vision may be due either to involvement of the fovea by SRF or, less frequently, obstruction of the visual axis by a large upper bullous RD.

Signs:Marcus gunn pupilLow IOP relative‘Tobacco dust’[shafer’s sign]Retinal breaksMild iritis

Lattice degeneration

 More commonly in moderate myopes and is the most important degeneration directly related to RD.

Laterality- bilateralLocation: Commonly -temporal superiorly fundus. 40% of eyes with RD.

Pathology Discontinuity of internal limiting membrane Atrophy of the underlying NSR. Vitreous - Overlying an area of lattice is synchytic -attachments around the margins are

exaggerated

 

  3    Signs      Spindle-shaped areas of retinal thinning between the equator and the posterior border

of the vitreous base.   •    Arborizing network of white lines within the islands    •    Associated with ‘snowflakes’ (remnants of degenerate Müller cells.   •    Associated hyperplasia of the RPE is common .   •    Small holes within lattice lesions are common and usually innocuous

Snailtrack degeneration

Sharply demarcated bands of tightly packed ‘snowflakes’ - white frost-like appearance.

longer islands than in lattice degeneration Associated with overlying vitreous

liquefactionVitreous traction at the posterior border of

the lesions is seldom present so that tractional U-tears rarely occur,

Round holes within the snailtracks may be present

White with pressure’

Translucent grey appearance of the retina - indenting the sclera.

In normal eyes Associated with abnormally strong

attachment of the vitreous gel Along the posterior border of islands of

degenerations.     

‘White without pressure’

Without scleral indentation. Mistaken for flat holes.Giant tears occasionally develop along the posterior

border For this reason, if ‘white without pressure’ is found in

the fellow eye of a patient with a spontaneous giant retinal tear, prophylactic therapy should be performed

360° cryotherapy / indirect argon laser photocoagulation, irrespective of the presence of ‘white without pressure’, if they have not developed a PVD.

Fresh Retinal detachment

The RD has a convex configuration and a slightly opaque and corrugated appearance as a result of retinal oedema

Loss of the choroidal pattern Retinal blood vessels - darker than in flat retina

   2    SRF extends up to the ora serrata - rare cases caused by a macular hole in which the

SRF is initially confined to the posterior pole - thinness of the retina at the fovea, a pseudohole is frequently seen if the posterior pole is detached.    3    B-scan ultrasonography shows good mobility of the retina and vitreous

Long-standing retinal detachment

Retinal thinning secondary to atrophy Secondary intraretinal cysts disappear after

retinal reattachment.Subretinal demarcation lines (‘high water

marks’) caused by proliferation of RPE cells at the junction of flat and detached retina

Proliferative vitreoretinopathy

Contraction of Epiretinal & Sub retinal membranes - tangential retinal traction and fixed retinal folds.

following surgery for rhegmatogenous RD or penetrating injury.

No previous vitreoretinal surgery for RD. Signs - Retinal folds and rigidity retinal mobility induced by eye movements or

scleral indentation is decreased

  

  1    Grade A (minimal) PVR -diffuse vitreous haze and tobacco dust. - pigmented clumps on the inferior surface of the retina.

   2    Grade B (moderate) PVR - wrinkling of the inner retinal surface, - tortuosity of blood vessels - decreased mobility of vitreous gel and rolled edges of retinal

breaks.

   3    Grade C (marked) PVR - rigid full-thickness retinal folds with heavy vitreous condensation

and strands.

   4    B-scan ultrasonography in advanced disease shows gross reduction of retinal mobility with retinal shortening and the characteristic triangular sign .

How to find the retinal break – fundus drawing

Prophylaxis of RRD

Important criteria for selection- - Characteristics of Break - Other considerations

Characteristics of Break :- Type- Size- Symptomatic- Location- Pigmentation

Other Considerations: - Cataract surgery - Myopic patients - Family history - Systemic diseases

Choice of treatment modalities

(a) laser using a slit-lamp delivery system(b) laser using an indirect ophthalmoscopic

delivery system combined with scleral indentation

(c) cryotherapy. CONSIDERATIONS:--Location of Lesion- Clarity of media- Pupil size

Laser photocoagulation

CRYOTHERAPY

INDICATIONS FOR URGENT SURGERY

Position of Primary breakSize of the breakState of Vitreous gel

Pneumatic retinopexy

Scleral buckling

Dr. Miratashi41

R.D.

Drainage of subretinal fluid

   1    Indications. Although a large proportion of RDs can be treated successfully with non-drainage techniques, drainage of SRF may be required under the following circumstances:   

a    Deep SRF beneath the retinal break. In such case the application of cryotherapy may be difficult or impossible.   

•    Drain the SRF to bring the break closer to the RPE.   •    Air injection into the vitreous cavity to counteract the hypotony induced by drainage.

   •    Cryotherapy to the break.   •    Explant insertion.

   b    Long-standing RDs tend to be associated with viscous SRF and may take a long time (many months) to absorb. Drainage may therefore be necessary to restore macular attachment quickly, even if the break itself can be closed without drainage.

  

2    Technique    a    ‘Prang’    •    Digital pressure is applied

to the globe until the central retinal artery is occluded and complete blanching of the choroidal vasculature is achieved in order to prevent haemorrhage from the drainage site.   •    A full-thickness perforation is made in a single, swift but controlled fashion with the tip of a 27-gauge hypodermic needle bent 2 mm from the tip.   •    Following drainage of SRF, air is injected to restore intraocular pressure.

b    ‘Cut-down’    •    The sclerotomy site should be beneath the area of deepest SRF but avoiding the vortex veins.   •    A radial sclerotomy is performed, about 4 mm long and of sufficient depth to allow herniation of a small dark knuckle of choroid.   •    A mattress suture is placed across the lips of the sclerotomy (optional).   •    The assistant holds apart the lips and the prolapsed knuckle is inspected with a +20 D lens for the presence of large choroidal vessels.   •    If large choroidal vessels are absent, gentle low-heat cautery is applied to the choroidal knuckle to decrease the risk of bleeding.   •    If this does not result in drainage of SRF the choroidal knuckle is perforated with a 25-guage hypodermic needle on a syringe.