Classification

Intra-retinal Degenerations: microcystoid degenerations (Typical & Reticular), senile retinoschisis, pars plana cysts
Retino-vitreal degenerations: Lattice degeneration, Snail-track degeneration, White with & without pressure
Chorioretinal degenerations: Paving stone degeneration

Intra-Retinal Degenerations

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.

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

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

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

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

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.

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

Engstrom RE, Glasgow BJ, Foos RY, Straatsma BR. Degenerative Diseases of the Peripheral Retina. Duane's Ophthalmology. Chapter 26. 2006 Edition.
Lewis H. Peripheral retinal degenerations and the risk of retinal detachment. Am J Ophthalmol. 2003 Jul;136(1):155-60.