Peripheral Retinal Degenerations

From EyeWiki
Original article contributed by: Dr Jay Chhablani, Dr. Anupam Basant Bagdi MBBS
All contributors: Dr Jay Chhablani, Peter A.Karth, MD and Vinay A. Shah M.D.
Assigned editor: Peter A.Karth, MD
Review: Assigned status Update Pending by Vinay A. Shah M.D. on January 20, 2015.
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Classification[edit | edit source]

1. Intra-retinal Degenerations : microcystoid degenerations (Typical & Reticular), senile retinoschisis, pars plana cysts

2. Retino-vitreal degenerations : Lattice degeneration, Snail-track degeneration, White with & without pressure

3. Chorioretinal degenerations : Paving stone degeneration

Intra-Retinal Degenerations[edit | edit source]

Microcystoid degeneration[edit | edit source]

Most frequent degenerative lesion of the area - Characterized by small bubbles or vacuoles in the peripheral retina near ora - These occur in the outer plexiform and inner nuclear layers of retina - Mostly symmetrical, more in temporal retina than nasal, more superiorly than inferiorly - Inner wall of a cyst may be absent giving impression of that of a retinal hole which is actually a pseudo-hole - Does not predispose to retinal detachment - A second type of degeneration called Reticular Cystoid Degeneration has been seen in eyes of cadavers. These are histologically different and more posterior compared to regular cystoid.

Senile Retinoschisis[edit | edit source]

Occurs in about 2 – 4% of population above 40 years of age - Lesion appears like a bullous elevation of peripheral retina and lies mainly in the temporal segment specially infero-temporal segment - It is the result of extension of microcystoid degeneration and similar pathogenic factors can be considered like traction by zonular fibres and poor peripheral vascularization - No vitreous alteration specific to this lesion - Mostly asymptomatic - It remains immobile with movement of eyeball and produces an absolute field defect (to differentiate from bullous RD) - It may enlarge to involve posterior pole or may lead to Retinal detachment especially if a break is present in either/both walls

Pars Plana Cysts[edit | edit source]

Clear bullous elevation of non-pigmented ciliary epithelium of pars plana - Usually more prominent temporally underneath the vitreous base - Content is usually clear and has been found to contain hyaluronic acid - In patients with abnormal serum proteins, like in multiple myeloma, the cysts may contain abnormal protein, giving them a turbid appearance - Seen in 5 – 10 % of all eyes examined - Bilateral in one third cases and show no sex predilection - These are harmless lesions not associated with serious eye complications

Retino-Vitreal Degenerations[edit | edit source]

Lattice Degeneration[edit | edit source]

Snail track degeneration[edit | edit source]

Characterized by groups of glistening white dots (which have been compared to frost granules or salt) - Occurs mainly in young and myopic eye - Frequency does not increase with age - Always found in the area of the equator or just in front of it - Histologically, this lesion consist of degeneration of the neural elements of retina leading to an atrophy of the tissues with lipid deposits in the internal retinal layers - Many authors consider it to be early stage of lattice degeneration - It may lead to development of a retinal break and also RD. In many studies the incidence of RD as a complication has been reported to be between 10 to 20 %. - Prophylactic intervention for this lesion has been debated

White With Pressure[edit | edit source]

Distinctive milky white or opalescent appearance of the peripheral retina that is observed in many normal eyes when examined with scleral depression - Retina appears normal without depression - It is common and seen in around 30 to 35% of eyes examined with scleral depression - Infero-nasal quadrant least likely to be affected - Incidence increases with age , no sex predilection - Benign condition not associated with retinal breaks - Must be carefully distinguished from a subclinical peripheral RD

White Without Pressure[edit | edit source]

Distinctive white appearance of the peripheral retina without indentation - Whiter than the retina in white with pressure and the choroidal markings are almost obscured - Whiteness further accentuated if scleral depression done - Margins are sharply demarcated from normal retina - Intervening patches of normal retina should not be confused with retinal holes - Exact cause is unknown , one school of thought states it to be a manifestation of peripheral vitreous traction while one believes it to be simply an abnormal reflex from a structurally normal VR interface - Frequently causes confusion with subclinical RD and Retinoschisis but indentation clearly reveals that retina is still apposed to the RPE.

Chorioretinal Degenerations[edit | edit source]

Paving Stone Degeneration[edit | edit source]

Has a dramatic appearance, revealing multiple rounded punched-out areas of choroidal and retinal atrophy - Located between ora and equator with size of one to several disc diameters - More common in infero-nasal and temporal quadrants - Lesions are yellow-white in color with due to sclera being partly visible through the atrophic choroid - Large choroidal vessels seen running through the base - Lesions have discrete margins which may be pigmented - May become confluent - Frequently bilateral, no sexual predilection, increasingly common with age - Benign lesions not associated with complications