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Peripheral fundus & its disorders

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Information about Peripheral fundus & its disorders

Published on March 2, 2014

Author: RohitRao2

Source: slideshare.net

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Peripheral fundus & its disorders
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Peripheral fundus & its disorders Presented by Dr Rohit Rao

References • Peripheral Ocular Fundus 3rd edition by William L. Jones • Ophthalmology 3rd edition.by Yanoff, Duker • Clinical ophthalmology 7th Edition - Jack Kanski • Wolff's Anatomy of the Eye and Orbit 8th by Bron, Tripathi. • Retina by Stephen.J .Ryan

Retina Optic Disc Peripheral Retina Ora Serrata Area Centralis Perifoveal Parafoveal Fovea Foveola

Near Periphery: 1.5mm Around Area Centralis Periphera Retina Mid Periphery: 3mm Wide Zone Around Near Periphery Far Periphery: Extendes From Optic Dics, 9-10mm Temoprally & 16mm Nasally

N T

Pars plana • Ciliary body starts 1 mm from the limbus and extends posteriorly for about 6 mm. • First 2 mm pars plicata and 4 mm pars plana. • Width is about 4.0-4.5 mm.

Vitreous base • Vitreous base is a 3–4 mm wide zone straddling the ora serrata. • Vitreous is strongly attached at base, so that following PVD, posterior hyaloids face remains intact. • Pre-existing retinal holes within the vitreous base do not lead to RD. • Severe blunt trauma may cause tearing of nonpigmented epithelium of pars plana & of retina.

Ora Serrata • Retina becomes opalescent and often is marked by small rows of cystoid cavities. • Extensive cystoid changes do not represent pathology. • Neural retina stops abruptly at ora serrata and is continued by nonpigmented ciliary epithelium • Pars plana is more deeply pigmented, so choroidal pattern not seen.

0.7-0.8 mm N 2.1 mm 7.0 mm T N 6.0 mm 7.0 mm 7.0 mm T

• Dentate processes are teeth-like extensions of retina onto the pars plana. • Oral bays are the scalloped edges of the pars plana epithelium in between the dentate processes. • Enclosed oral bay is a small island of pars plana surrounded by retina as a result of meeting of two adjacent dentate processes. ▫ Not be mistaken for a retinal hole • Granular tissue characterized by multiple white opacities within the vitreous base ▫ Can be mistaken for small peripheral opercula.

Enclosed oral bay Granular tissue

Meridional fold • Small radial fold of thickened retinal tissue in line with a dentate process, • It bigns at ora serrata and runs posteriorly & perpendicularly to it in a meridional fashion • Superonasal quadrant . • Small retinal hole at its apex • Found in approximately 20% of all eyes • Meridional complex is composed of an enlarged dentate and ciliary process associated with a meridional fold

• Vitreous traction on meridional folds and complexes may result in the formation of retinal breaks. • Meridional folds are not a common cause of RD, may be because these are found at vitreous base. • Because of anterior location , cryopexy is

Pars plana cyst • Pars plana cysts are clear cystoid spaces between the pigmented and nonpigmented epithelia. • Scleral depression • Fluid contains hyaluronic acid. • Mostly acquired; few are congenital. • idiopathic or secondary to ocular disease. ▫ Retinal detachment, may be the result of traction by the shrinking vitreous base. ▫ Posterior uveitis. ▫ Multiple myeloma

Congenital Hypertrophy of the Retinal Pigment Epithelium • Common benign lesion. • Congenital and not a degenerative condition. • Flat round or oval lesion, well defined, dark grey or black in colour and up to three disc diameters in size. • Outer retina change and does not affect the vitreo-retinal interface; so does not predispose to RD. • Can lose pigment over time

• When occur in groups, known as bear track, Familial Adenomatous Polyposis.

Pavingstone(Cobblestone degeneration or Chorioretinal Atrophy) • 25% of the population • Well defined yellow white patches between the equator and the ora serrata. • Absence of the outer layers of the retina, in particular the choroid, which permits an uninterrupted view of the sclera. • Congenital and not be considered a degeneration. • No predisposition to break formation

Microcystoid degeneration • Tiny vesicles with indistinct boundaries. • Always starts adjacent to ora serrata and extends circumferentially and posteriorly with a smooth undulating posterior border. • Present in all adult eyes, • Increasing in severity with age • Although it may give rise to retinoschisis. • Do not give rise to RD

Honeycomb (reticular) degeneration • Age-related change • Fine network of perivascular pigmentation which may extend posterior to equator. • Caused by RPE degeneration • More prominent in nasal quadrant

Snowflake Vitreoretinal Degeneration • Snowflake vitreoretinal degeneration appears as tiny yellow-white spots in the far peripheral retina • Superior temporal quadrant • Lattice degeneration • Vitreous shows fibrillar degeneration & liquefaction.

Lattice degeneration • • • • • • • • • • An Area with Absence of ILM Overlying Area of Liquefied Vitreous Condensation & Adherence of Vit Gel Inner Retinal Layer Atrophy More common superiorly Arranged parallel to the ora serrata. Incidence- 8% to 10% RRD :: Lattice account for 20% Symmetric and bilateral, Horse shoe Tears &Atrophic holes

Complications (A) Atypical radial lattice without breaks; (B) U-tears (C) Linear tear along posterior margin. (D) multiple small holes within islands of lattice

Management of Lattice Degeneration • • • • Lattice without Retinal Breaks - No Rx Lattice with Atrophic Holes - No Rx Lattice + Holes+ Sub clinical RD – Treat Lattice+ Traction Tear - Treat : If Fellow eye has RD,Strong Family History of RD,Aphakic Eyes • Asymptomatic Traction Tear - No Rx • Acute Symptomatic Tears - Treat in Phakics & Aphakics

Vitreoretinal Tufts • Small Peripheral Retinal Elevation • Focal Vitreous Traction • Operculated or flap tears when strong vitreous traction is applied • Rarely cause retinal detachments. • Treatment is rarely indicated • Cryopexy or photocoagulation.

Snailtrack degeneration • Snailtrack degeneration is characterized by sharply demarcated bands of tightly packed ‘snowflakes’ which give the peripheral retina a white frost-like appearance. • Longer than in lattice degeneration • Overlying vitreous liquefaction.

Degenerative retinoschisis • 5% of the population over the age of 20 years and is particularly prevalent in hypermetropes. • Bilateral • Coalescence of cystic lesions • Results in separation or splitting of the NSR into an inner (vitreous) layer and an outer (choroidal).

• Typical retinoschisis split is in outer plexiform layer, • Reticular retinoschisis, less common, splitting occurs at level of NFL. • Early retinoschisis seen in inferotemporal with a smooth immobile elevation of retina. • Progress circumferentially • Snowflakes , sheathing or ‘silver-wiring’ of blood vessels. • Microaneurysms and small telangiectases , • Complications are very rare, • Breaks, RD in the presence of PVD, Vitreous haemorrhage

White with pressure • Translucent grey appearance of the retina, induced by indention. • It does not move when indenter is moved. • Normal eyes and may have abnormally strong vitreous attachment. • It is also observed along the posterior border of islands of lattice degeneration, snailtrack degeneration and the outer layer of acquired retinoschisis.

White without pressure • Has the same appearance but is present without scleral indentation. • May be mistaken for a flat retinal hole. • Giant tears occasionally develop along the posterior border of ‘white without pressure’. • 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. • It is advisable to treat all fellow eyes of non-traumatic giant retinal tears prophylactically by 360° cryotherapy or indirect argon laser photocoagulation, irrespective of the presence of ‘white without pressure’, if they have not developed a PVD.

TREATMENT • Upon the discovery of a retinal break, the initial decision is whether the benefits of treatment (to prevent retinal detachment) outweigh the risks and cost of treatment • The factors under consideration in each case include ▫ ▫ ▫ ▫ ▫ ▫ Presence or absence of symptoms; Age and systemic health of the patient; Refractive error of the eye; Location, age, type, and size of the break; Status of the fellow eye; Whether the patient is aphakic, pseudophakic, or will soon undergo cataract surgery

• Retinopexy • Cryopexy and laser photocoagulation. • Cryotherapy ▫ Delivered transconjunctivally. ▫ It destroys the choriocapillaris, RPE, and outer retina to provide a chorioretinal adhesion ▫ It is not immediate; 1 week for partial adhesion and up to 3 weeks for the complete. • Laser photocoagulation ▫ Argon green, argon blue-green, krypton red, or diode laser. ▫ Slit lamp and the indirect ophthalmoscope. ▫ Instant, but maximal adhesion occurs 7–10 days later.

• Cryopexy has the advantage of not requiring clear media • In general, retinal cryopexy and indirect ophthalmoscopic laser photocoagulation are preferred for anterior retinal breaks • Similarly, posterior breaks managed with the slit lamp or an indirect laser delivery system. • Retinal tear with persistent traction and recurrent vitreous Hemorrhage requires scleral buckling or vitrectomy

Cryopexy • Indirect ophthalmoscopic visualization, • Cryoprobe is placed on the conjunctiva that overlies the break until the retina adjacent to the tear becomes gray-white. • Approximately 2 mm of retinal whitening around the entire break • Multiple applications are placed until the break is surrounded completely with confluent treatment. • Do not to treat the choroid and RPE directly beneath the break, can lead to macular pucker and proliferative vitreoretinopathy.

Photocoagulation • Goldmann three-mirror lens or panfundoscope lens with the slit-lamp delivery system. • Tear should be surrounded completely by three to four rows of laser burns. • Settings are 200–500 mm spot size and 0.1–0.2 seconds • Indirect laser delivery system can also be used • Advantage is simultaneous scleral depression allows treatment of anterior tears and even dialysis.

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