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PATHOGENESIS AND SIGNS OF RETINAL DETACHMENT (RD)

PATHOGENESIS AND SIGNS OF RETINAL DETACHMENT (RD). 1. Rhegmatogenous RD. Fresh Longstanding Proliferative vitreoretinopathy (PVR). 2. Diabetic tractional RD. 3. Exudative RD. 4. Differential diagnosis RD. Definition and classification.

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PATHOGENESIS AND SIGNS OF RETINAL DETACHMENT (RD)

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  1. PATHOGENESIS AND SIGNS OF RETINAL DETACHMENT (RD) 1. Rhegmatogenous RD • Fresh • Longstanding • Proliferative vitreoretinopathy (PVR) 2. Diabetic tractional RD 3. Exudative RD 4. Differential diagnosis RD

  2. Definition and classification • Break - full-thickness defect in sensory retina • Hole - caused by chronic retinal atrophy • Tear - caused by dynamic vitreoretinal traction Morphology of tears a. Complete U-tear b. Linear c. Incomplete L-shaped d. Operculated e. Dialysis

  3. Retinal detachment (RD) Separation of sensory retina from RPE by subretinal fluid (SRF) Rhegmatogenous - caused by a retinal break Non-rhegmatogenous - tractional or exudative

  4. Indirect ophthalmology Condensing lenses Technique • Keep lens parallel to patient’s iris plane • Avoid tendency to move towards patient • Ask the patient to move eyes and head • into optimal positions for examination • The higher the power, the less the • magnification, the shorter the working • distance but the greater the field of view

  5. Fundus drawing Technique Colour code Breaks Detached retina Vitreous opacity Thinning Exudate Lattice Retinal pigment • Place chart upside down • Draw what you see

  6. Pathogenesis of rhegmatogenous RD • Two components for retinal break formation • Acute posterior vitreous detachment (PVD) • Predisposing peripheral retinal degeneration Possible sequelae of acute PVD Retinal tear formation and haemorrhage (10-15%) Avulsion of retinal vessel and haemorrhage (uncommon) Uncomplicated PVD (85%)

  7. Predisposing peripheral degenerations

  8. Retinal breaks not requiring treatment g - Small asymptomatic holes near ora serrata e - Asymptomatic dialysis surrounded by pigment h - Small inner layer holes in retinoschisis f - Breaks in both layers of retinoschisis

  9. Complications of lattice degeneration • No complications - in most cases • RD associated with atropic holes, particularly in young myopes • RD associated with tractional tears in eyes with acute PVD Indications for prophylaxis • RD in fellow eye • Extensive lattice in high myopia

  10. PROPHYLAXIS OF RHEGMATOGENOUS RETINAL DETACHMENT 1. Retinal breaks 2. Predisposing degenerations • Lattice • Snailtrack • White-without-pressure 3. Treatment modalities • Laser photocoagulation • Cryotherapy 4. Benign peripheral degenerations

  11. pulled away from the underlying choroid • small areas of the retina torn => retinal tears or retinal breaks • retinal cells deprived of oxygen • if not promptly treated =>permanent vision loss

  12. Fresh rhegmatogenous RD - signs • Annual incidence - 1:10,000 of population • Eventually bilateral in 10% • Convex, deep mobile elevation • extending to oraserrata • Slightly opaque with dark blood vessels • Loss of choroidal pattern • Retinal breaks Longstanding rhegmatogenous RD - signs • Frequently inferior with small holes • Very thin retina • Secondary intraretinal cysts • Demarcation lines (high-water marks)

  13. Proliferative vitreoretinopathy Grade A (minimal) Grade B (moderate) Grade C (severe) • Vitreous haze and • tobacco dust • Retinal wrinkling and • stiffness • Rolled edges of tears • Rigid retinal folds • Vitreous condensations • and strands Signs of diabetic tractional RD • Concave, shallow immobile elevation • Highest at sites of vitreoretinal traction • Slow progression and variable fibrosis • Does not extend to ora serrata

  14. Pathogenesis of diabetic tractional RD (1) Antero-posterior traction RD Preretinal haemorrhage

  15. Pathogenesis of diabetic tractional RD (2) A-P traction Bridging traction Preretinal haemorrhage

  16. Pathogenesis and Causes of Exudative RD • Damage to RPE by subretinal disease • Passage of fluid derived from choroid into subretinal space 1. Choroidal tumours • Primary • Metastatic 2. Intraocular inflammation • Harada disease • Posterior scleritis 3. Systemic • Toxaemia of pregnancy • Hypoproteinaemia 4. Iatrogenic • RD surgery • Excessive retinal photocoagulation 5. Miscellaneous • Choroidal neovascularization • Uveal effusion syndrome

  17. Signs of exudative RD • Convex, smooth elevation • May be very mobile and deep with • shifting fluid • Subretinal pigment (leopard spots) • after flattening

  18. SYMPTOMS • floaters • light flashes • shadow or curtain over a portion of visual field • blur in vision

  19. Can occur as a result of: • trauma • advanced diabetes • an inflammatory disorder, such as sarcoidosis • shrinkage of the jelly-like vitreous that fills the inside of the eye

  20. Factors that may increase risk of retinal detachment: • aging - more common in people older than 40 • previous retinal detachment in one eye • family history of retinal detachment • extreme nearsightedness • previous eye surgery • previous severe eye injury or trauma

  21. TREATMENTS Retinal tears: • laser surgery (photocoagulation) • freezing (cryopexy) Retinal detachment: • pneumatic retinopexy • scleral buckling • vitrectomy

  22. SCLERAL BUCKLING

  23. VITRECTOMY

  24. Technique of cryotherapy • Surround lesion with single row of • cryo-applications • Preferred for treatment of large • areas

  25. PRINCIPLES OF RETINAL DETACHMENT SURGERY 1. Scleral buckling • Configuration of buckles • Preliminary steps • Localization of breaks • Cryotherapy • Insertion of local explant • Encircling procedure • Drainage of subretinal fluid • Causes of early failure 2. Pneumatic retinopexy 3. Vitrectomy • Giant tears • Proliferative vitreoretinopathy (PVR) • Diabetic tractional RD

  26. Configuration of scleral buckles Segmental circumferential Radial Encircling augmented by radial sponge Encircling augmented by solid silicone tyre

  27. Drainage of subretinal fluid Indications • Difficulty in localizing break • Immobile retina • Longstanding RD • Inferior RD Complications Haemorrhage Retinal incarceration

  28. Indications RD with superior breaks Pneumatic retinopexy Technique (a) Cryotherapy (b) Gas injection (c) Postoperative positioning (d) Flat retina

  29. Vitrectomy for PVR • Dissection of star folds and peeling of membranes • Injection of expanding gas or silicone oil Vitrectomy for diabetic tractional RD Release of circumferential traction Release of antero- posterior traction Endophotocoagulation

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