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3 mirror, retinal break.pptx
- 1. 3 mirror examinations and Retinal Breaks
- 2. 3 mirror Central mirror – : provide a direct view of the optic disc and macula Equatorial mirror ( the largest ) – enables visualization retinal equator. Angled approximately at 73 ̊ Gonioscopy mirror ( smallest & domed shaped) – used for gonioscopy or visualization of the extreme retinal periphery and pars plana. Inclined approximately 59 ̊ Peripheral mirror ( intermediate ) – view the fundus between the equator and ora serata . Angled approximately 66 ̊ 120 ̊ 73 ̊ 66 ̊ 59 ̊
- 3. • To visualize the entire fundus the lens is rotated for 360 using the equatorial mirror and then the peripheral mirrors.
- 5. Anatomy of vitreous • Composed of clear matrix of collagen , hylarunic acid and water • 2 portions : central core vitreous and cortical vitreous • Vitreous base : 3-4 mm wide zone straddling the ora serata, throughout which the cortical vitreous is strongly attached. • Sites of stronger adhesion in the normal eye include : - Vitreous base : very strong - Optic disc margin : fairly strong - Perifoveal : fairly weak - Peripheral blood vessels : usually weak
- 6. Posterior Vitreous Detachment • Definition : - separation of the cortical vitreous, along the delinating posterior hyaloid membrane ( PHM), from the neurosensory retina ( NSR) posterior to vitreous base. • Pathophysiology : - occurs d/t vitreous gel liquefaction with age ( synchysis) to form fluid-filled cavities and subsequently condensation ( syneresis) with access to the preretinal space allowed by dehiscence in cortical gel and PHM.
- 7. What is retinal break ???.. Is a discontinuities in the retinal surface What is retinal detachment ??.. Separation of the neuralsensory retina from the RPE Retinal detachment Rhegmatogenous retinal degeneration ( RRD) Full thickness defect in the sensory retina which permits fluid derived from synchytic vitreous to gain access to the subretinal space
- 8. Peripheral retinal lesions predisposing to retinal detachments • Lattice degeneration • Snailtrack degeneration • Cystic retinal tuft • Degenerative retinochisis • Zonular traction tuft • White with pressure and white without pressure • Myopic choroidal atrophy
- 9. Lattice degeneration • Present in about 8% in population, develop early in life with peak incidence 2nd or 3rd decades • Common in myopic eyes • Pathology : - Discontinuity of ILM with variable atrophy of the underlying NSR ( retinal thinning ) - Vitreous overlying an area of lattice is synchytic. - Vitreous attachments around the margins of lattice will undergo strong adhesion to the retina - Retinal thinning will disturb the RPE and cause RPE hyperplasia and pigmented epithelium • Sign : - Spindle-shaped areas of retinal thinning commonly at the equator and the posterior border of the vitreous base. ( Figure A) - Sclerosed vessels forming a network of white line characteristic. ( Figure B) - Small holes are common Wield field lattice degeneration : ( A ) Multiple lesion with small holes ( B ) Sclerosed vessels forming a characteristic white network
- 10. Lattice degeneration • Complications : - Tears may develop as consequent to a PVD, when lattice is sometimes visible on the flap of the tear. ( Figure C ) - Atrophic holes may rarely ( 2%) leads to RD, the risks higher in young myope pts. • Management : - Asymptomatic areas of lattice are not treated prophylactically even if retinal breaks are seen - Unless: RD in fellow eye - treatment of the fellow eye when extensive lattice ( > 6 clock hours) is present High myopia – associated with higher risk of detachment. Wield field lattice degeneration : (C) retinal detachment with lattice on the flap of tear
- 11. Snailtrack degeneration • Characterized by sharply demarcated bands of tighly packeds ‘ snowflakes’ that gives peripheral retina a white frost- like appearance. • Vitreous traction is seldom present, U –tears rarely occur • Retinal holes are relatively common • Prophylactic treatment is usually unnecessary, review 1-2 years as RD occurs in minority.
- 12. Cystic retinal tuft • Known as ‘ granular patch’ or ‘ retinal rosette’. • Is a congenital abnormality consisting of a small , round or oval, discrete elevated whitish lesion in the equatorial or peripheral retina. Commonly in temporal. • Comprised of glial tissue , strongly vitreoretinal adhesion is commonly present • Both small round holes and horseshoe tear can occur. • 5-10% CRT eyes can leads to RD Cystic retinal tuft. ( A) : Isolated uncomplicated lesion (B) : tuft with small round hole
- 13. Degenerative retinochisis • Present in about 5% in population over the age of 20 yrs, particularly prevalent in hypermetropia. • Pathology : - Develop from microcystoid degeneration, resulting in separation of the NSR into inner and outer layers ( inner nuclear & outer plexiform layer) with severing of the neurones & complete loss of visual function in the affected area. • Symptoms : - Photopsia and floaters are absent as there is no vitreoretinal traction. - Rare for pt to have visual defect, even with spread posterior to equator. - Occasional symptoms result from VH or progressive RD. • Signs : - Early retinochisis usually involves the extreme inferotemporal periphery, appearing as an exaggeration of microcystoid degeneration with a smooth immobile dome-shaped elevation of the retina. - The elevation is convex, smooth, thin and immobile, unlike the opaque and corrugated appearance in RRD - Demarcation line – indicate presence of associated RD - Surface of the inner layer may show ‘ snowflakes’ ( whitish remnants of Muller cells footplates) - Inner layer breaks are small and round while the outer layer breaks are usually larger with rolled edges
- 14. Degenerative retinochisis • Complications: - RD is rare, incidence is only around 1%. - Detachment is almost always asymptomatic and infrequently progressive and rarely requires surgery. - VH is rare • Management : - A small peripheral RS, especially if break is not present in both layers, can review every 1-2 years. - A large RS if breaks present in both layers / it extends posterior to the equator – HVF and OCT may be useful to do. - OCT – useful to distinguish between RS and RD - Retinopexy or surgical repair – for RS progression to fovea - Recurrent VH may require vitrectomy.
- 15. Zonular traction tuft • Phenomenon caused by an abberrant zonular fibre extending posteriorly to be attached to the retina near ora serata and exerts traction on the retina at its base. • Typically located nasally • The risk of retinal tear formation – 2%
- 16. White with pressure and white without pressure White with pressure ( WWP ) • Refers to retinal areas in which translucent white grey appearance can be induced by scleral indentation. • May present along the posterior border of lattice degeneration, snailtrack degeneration and the outer layer of acquired retinochisis. • Frequently seen in normal eyes. • May be ass with abnormally strong attachment of the vitreous gel. • May not indicate a higher risk of retinal break formation.
- 17. White with pressure and white without pressure White without pressure (WWOP) • Same appearance as WWP but is present without scleral indentation • Corresponds to an area of fairly strong adhesion of condensed vitreous. • Retinal breaks, including giant tears occasionally develop along the posterior border of WWOP. • If WWOP found in the fellow eye of a pt with spontaneous giant retinal tear, prophylactic therapy should be considered.
- 18. Myopic choroidal atrophy • Diffuse choroidal/ chorioretinal atrophy in myopia – is characterized by diffuse or circumscribed choroidal depigmentation. • Commonly ass with thinning of overlying retina and occurs typically in the posterior pole and equatorial area of highly myopic eyes. • Retinal holes may occasionally lead to RD.
- 19. Types of retinal breaks • Retinal hole • Retinal tear • Giant retinal tear • Dialysis
- 20. Types of retinal breaks 1. Retinal hole - Full thickness retinal defect due to atrophy without vitreoretinal traction. - It may be associated with peripheral degeneration, e.g ; lattice or snailtrack - Operculated hole -> is used to denote a hole caused by PVD where the operculum has avulsed and now free- floating within the vitreous. Figure B : Operculated hole Figure C : Round holes ; white arrows ( atrophic holes ) , black arrow ( operculated hole with localized subretinal fluid )
- 21. Types of retinal breaks 2. Retinal tear - Full thickness U-shaped defect due to PVD. - Associated with abnormal vitreous adhesion e.g lattice degeneration ** Ongoing vitreoretinal traction at flap apex causes progression to RRD in at least 1/3 of the cases.
- 22. Types of retinal breaks 3. Giant retinal tear - A variant of U tear, involving 90 ̊ or more of the retinal circumference - Located in the peripheral retina at the posterior border of the vitreous base - Associated with i. systemic disease( e.g Marfan’s syndrome and Stickler syndrome) ii. Trauma iii. High myopia - In contrast to dialysis, vitreous gel remains attached to the anterior margin of the break
- 23. Types of retinal breaks 4. Dialysis - Full thickness circumferential tear along the ora serata. - Vitreous gel remains attached to posterior margin. - Can cause RD, often slowly progressive in the absence of PVD. - It may arise spontaneously or after trauma . - Typically appear as large very peripheral breaks with regular rolled edge.
- 24. Risk factors for RRD according to type of break - Giant retinal tear in the other eye - U-tear, large hole or dialysis - Asymptomatic small round holes - Breaks within the vitreous base High risk Low risk
- 25. Risk factors for RRD according to other ocular and systemic Ocular Systemic Other eye Retinal Lenticular General Refractive -Stickler syndrome -Marfan’s syndrome -Ehlers- Danlos syndrome Previous contralateral retinal detachment ( esp giant retinal tear) -Lattice degeneration -Retinochisis -Retinal necrosis ( CMV, ARN/ PORN) -Aphakia -Pseudophakia ( esp complicated surgery e.g Vitreous loss) -Posterior capsulotomy Myopia -Trauma ( blunt/ penetrating - Surgery
- 26. Identification of the retinal breaks • Distribution of breaks : - 60% superotemporal quadrant, 15% superonasal, 15% inferotemporal and 10% inferonasal. • Configuration of SRF : - SRF spread is governed by : Gravity Anatomical limits ( ora serata and optic nerve ) Location of primary retinal break
- 27. Lincoff’s rules A shallow inferior RD in which the SRF is slightly higher on the temporal side points to a primary break located inferiorly on that side. A primary break located at 6 oclock will cause an inferior RD with equal fluid levels. In a bullous inferior RD the primary break usually lies above the horizontal meridian.
- 28. Lincoff’s rules If the primary break at upper nasal quadrant the SRF will revolve around the optic disc and then rise on the temporal side until it is level with the primary break. A subtotal RD with a superior wedge of attached retina points to a primary break located in the periphery nearest its highest border. When the SRF crosses the vertical midline above, the primary break is near to 12 o’clock, the lower edge of the RD corresponding to the side of the break.
- 29. Management of retinal breaks • Treatment is controversial !!! - U tears ( especially if symptomatic ) should be treated usually by laser photocoagulation or less commonly cryotherapy . - Asymptomatic small round holes are commonly not treated. - Dialyses/ giant retinal tear are treated surgically : • Fluid-air exchange • Pneumatic retinopexy • Scleral buckling • Primary vitrectomy with gas or silicone oil tamponade or combined scleral buckle-vitrectomy . - Dialyses with no or limited retinal detachment are treated with laser/ cryotherapy.
- 30. Management of retinal breaks • Fellow eye treatment is also controversial !!! - In giant retinal tear, the fellow eye is often treated e.g. with 360 ̊ cryotherapy or laser . - In a case of simple RRD, lattice in the fellow eye is often not treated, unless there is additional risk factor e.g. high myopia, aphakia, etc
- 31. Management of retinal breaks 1. Laser retinopexy - 3 mirror contact lens -> settings : 0.1 s, 200 -300 um - Wide field lens -> starting power of 200mW, power should be adjusted as appropriate to obtain moderate blanching - Head- mounted BIO -> spot size is estimated and adjusted by adjusting the condensing lens ( usually 20D) positions Lesion is surrounded with two to three rows of confluent burns.
- 32. Management of retinal breaks 2. Cryoretinopexy - For lesion behind the equator - Subconjunctival/ regional anaesthesia is commonly required. - A small conjunctival incision may be necessary. - Lid speculum is used - The instrument should initially be purged ( e.g. 10s at -25C, repeating after a minute ) - Under BIO visualization, the lesion is indented & foot pedal depressed until visible whitening of the retina is seen. - The eye usually padded afterwards, analgesia is commonly necessary. After treatment : Patient should avoid strenuous physical exertion for about a week until an adequate adhesion has formed, review should usually take place 1-2 weeks
- 33. Follow up 1. Patients with predisposing conditions or retinal breaks that do not require treatment - Followed every 6 to 12 months 2. Patients treated for a retinal breaks are reexamined in 1 week, 1 month, 3 months, and then every 6 to 12 months. 3. RD symptoms are explained and patients are told to return immediately if these symptoms develop. ( increase in floaters or flashing lights, worsening visual acuity, or the appearance of a curtain, shadow, or bubble anywhere in the field of vision)
- 34. References 1. Josel F, Maneli M. Basic science in Opthalmology : Physic and chemistry. Springer. 2013 59-60. 2. Mark R, Nicola L. Optometry: Science, Techniques and Clinical Management. Second edition. 2019; 287-288. 3. Maria H., Megan L. Management of Giant Retinal Tear Detachments. J Ophthalmic Vis Res. 2017 Jan-Mar; 12(1):93-97. 4. Alastair K.0, Philip I. Oxford Handbook of Ophthalmology. Third edition. 2014; 482-483 5. Brad B . Kanski Clinical Ophthalmology. Eighth edition. 2016; 686- 701.