Retina, Part 1: Peripheral Retinal Abnormalities

Educational Objectives

The goal of this program is to improve the management of peripheral retinal abnormalities. After hearing and assimilating this program, the clinician will be better able to:

1. Identify common anatomic variations of the retina.
2. Estimate the risk for retinal breaks associated with degenerative changes of the peripheral retina.
3. Differentiate between retinal detachment and retinoschisis.
4. Select cases in which prophylactic treatment of a retinal break would be appropriate.
5. Describe the pathogenesis of retinal detachment.

Summary

Anatomic characteristics of the peripheral retina: ora serrata — transitional structure between the retina and pars plana and is characterized by dentate processes that are more prominent on the nasal side; straddled by the vitreous base and is located more posteriorly to the limbus temporally than nasally; therefore, the posterior margin of the vitreous base is closer to the ora serrata temporally; vitreous — most firmly attached at the vitreous base, optic nerve head, peripheral posterior margin of the lens, and along major blood vessels

Anatomic Variations of the Retina

Meridional folds and complexes: meridional folds — accentuated dentate processes with elevated areas; 1969 study by Spencer of 400 autopsy eyes found meridional folds in 26% of patients; of these, 55% had bilateral folds and 27% had multiple folds; rarely associated with retinal breaks; meridional complexes — found in 16% of patients in the Spencer study; 55% of patients had bilateral complexes, and 45% had multiple complexes; characterized by an elevation in the middle portion of the meridional fold where the pars plana is continuous

Oral bays: occur when the most anterior portions of two dentate processes approach (partial) or touch (enclosed); study by Spencer found that 4% of eyes have an enclosed oral bay; 5 of 46 eyes with an enclosed oral bay had lesions at the posterior border of the vitreous base

Pars plana cysts: epithelial cysts of the pars plana that are oriented radially (longer in the anterior-posterior than circumferential direction); calcification within the fluid results in an intense white appearance and is termed an oral pearl

Retinal tufts: noncystic tufts — account for ≈72%; study by Foos found no association with retinal tears; cystic tufts — present in 5% of clinical cases and 59% of autopsy cases; studies from the 1960s suggested that these are associated with a small risk for retinal tears, although this may be debatable based on current experience; zonular traction tufts — occur with abnormally posterior insertion of zonules; described in 16% of autopsy eyes and associated with retinal holes in 4% of cases; generally not thought to have potential for retinal detachment (RD); retinal tags — mediated by the insertion of the vitreous into the retina and considered to be a lamellar break of the peripheral retina; retinal pits — equivalent of operculated partial retinal breaks; inner retinal tissue is elevated from the plane of the retina and is in the peripheral vitreous; these thinned areas of the retina may be mistaken for a peripheral retinal break or round hole

White with or without pressure (WWP): circumferentially oriented and extend for at least a few clock hours; the surface of the retina appears whiter than the border retina and may have scleral indentation; pathogenesis is unknown but thought to represent exaggerated surface traction caused by vitreoretinal adhesion; incidence increases with age; typically present in the superior quadrants and bilaterally; important to distinguish from RD, which is more elevated and less circumferential

Degenerative Changes

Cobblestone degeneration: typically located in the inferotemporal portion of the retina; incidence increases with age (incidence in individuals >60 yr of age is ≈30% according to autopsy studies) and represents ischemic atrophy of the outer retina; most cases are <1 disk diameter (DD) in size but may extend into an entire quadrant; histopathologic features include an accentuated vitreoretinal or chorioretinal attachment with a loss of the outer retinal layers

Peripheral cystoid degeneration: most common abnormality and is primarily a histopathologic feature; may be categorized as typical or reticular; typical subtype — has a smooth and regular contour on the surface, is usually present inferotemporally, and is located in the outer plexiform layer (OPL); reticular subtype — has an angulated and irregular contour, accounts for ≈18% of cases, is located in the nerve fiber layer (NFL), and is located more posteriorly than the typical form

Lattice degeneration

Prevalence: large histopathologic series by Straatsma showed a frequency of 11%; study by Foos found a frequency of 16%, of which 45% were bilateral and 47% were multiple; a large prospective clinical series by Byer found a frequency of 7%

Characteristic features: include sharply demarcated areas of thinning, retinal discoloration (whitening with hyperpigmentation), circumferential orientation with an oval shape at the ends, location that is anterior to the equator, hyperpigmentation or depigmentation of the retinal pigment epithelium (RPE), and interlacing white lines (present in ≈25% of cases); round holes may be present and represent atrophy of the retina within the zone of lattice degeneration; liquefaction of the overlying vitreous, exaggerated vitreoretinal attachments at the edges, and tears along the lateral and posterior margins may also be observed; radial and perivascular lattice degeneration are atypical and may be observed with Stickler syndrome; 1989 report by Byer that followed 276 patients for 1 to 25 yr (mean of 11 yr) showed that ≈1% of patients developed clinical RD (defined as >1 DD of subretinal fluid around the margin of lattice), and 6.7% of patients had subclinical RD (<1 DD of subretinal fluid); 60% of the subclinical cases were new findings identified during the course of follow up; 35% of eyes with lattice degeneration also had atrophic holes; all subclinical cases were associated with atrophic holes, and none were symptomatic; 8 eyes (2%) in the study had tractional tears, 4 of which were symptomatic and treated; however, 2 of the new tears were not associated with lattice degeneration

Treatment considerations: treatment of asymptomatic lattice degeneration is not indicated because it is unlikely to progress to clinical RD; study by Benson found that cryopexy is associated with late complications in 5.4% of cases, eg, extension of the tear, tears occurring elsewhere, or vitreous hemorrhage with an avulsed vessel; risk for RD is approximately 2 times higher with lattice degeneration; the decision to treat prophylactically depends on presence of additional risk factors, eg, previous RD in the fellow eye, scheduled cataract surgery (although this may be less important with improvement in techniques), and high myopia

Retinoschisis:

Subtypes: typical — usually flat and located anteriorly, and outer holes are less common than with the reticular subtype; glistening white dots on the surface and an irregular “beaten metal” appearance are common; reticular subtype — more bullous and posterior, more frequently associated with outer holes, has a thinner inner retinal layer, and has a honeycomb appearance; other classifications — include X-linked or secondary (eg, tractional or inflammatory) types

Study by Byer: prevalence and characteristics — 218 patients were followed for 1 to 21 yr (mean of 9 yr); a prevalence of 1% was observed; of these cases, 85% were bilateral, 72% were inferotemporal, 74% extended behind the equator, 11% had inner retinal breaks, and 75% had outer retinal breaks; outcomes — resolution occurred in 4%, new areas of retinoschisis developed in 10%, posterior extension developed in 3%, and lateral extension developed in 6%; 6% of patients developed asymptomatic RD, although none were treated; studies suggest that retinoschisis is unlikely to be a precursor for RD and can be safely observed

Juvenile X-linked retinoschisis (XLRS): features include foveal schisis with honeycomb appearance and coalescence of radial schisis areas; schisis occurs in the nerve fiber layer (whereas it occurs in the outer plexiform layer in the typical form of retinoschisis); peripheral retinoschisis is also present in ≈50% of patients; decrease in visual acuity is modest, with visual acuity of 20/40 or better in 30% of cases; bleeding into the retinoschisis cavity may occur

Differentiation between retinoschisis and RD: laterality — retinoschisis is bilateral in ≥75% of cases, whereas RD is typically unilateral and symptomatic; scotoma — if retinoschisis extends posteriorly enough to be symptomatic, an absolute scotoma is typically present; an RD is typically associated with a relative scotoma; vitreous — more likely to be clear in retinoschisis, whereas vitreous pigment or hemorrhage is common in RD; posterior vitreous detachment (PVD) is usually present in RD, but not necessarily in retinoschisis; surface — relatively smooth with retinoschisis, whereas the RD has areas of irregular elevation; retinoschisis has the same radius of curvature throughout the posterior extent, whereas RD may be more anterior in some zones and more posterior in others; RPE — retinoschisis does not typically have underlying changes, whereas atrophy may be observed in chronic RD; scleral indentation — with retinoschisis, the inner retina moves in concert with the indentation motion, whereas an RD moves independent of the indentation because fluid can move freely in and out of the break; laser test — study by Lincoff found that applying a laser to retinoschisis resulted in a white spot, which shows that the deep layers of retina remain attached to the choroid and RPE; the white spots are not observed if the laser is applied to an RD; RD coincident with retinoschisis — treatment is the same as for other RDs and involves closing the tear

Treatment of XLRS: remains controversial; Rosenfeld reported modest success with drainage and fluid-air exchange

Vitreoretinal degenerations: subtypes — include snail track and snowflake degeneration; asteroid hyalosis consists of calcium and cholesterol deposits that are often bilateral but asymmetric; syneresis involves liquefaction of the vitreous and is associated with symptoms of floaters; PVD can be considered a degenerative change; diagnosis of Stickler syndrome should only be used in patients with other systemic abnormalities; if there are no systemic abnormalities, retinal changes not associated with RD are diagnosed as Wagner disease; retinal changes associated with RD are diagnosed as Jansen disease; other conditions include Goldmann-Favre syndrome, hereditary night blindness, familial exudative vitreoretinopathy (FEVR), and primary amyloidosis

Familial exudative vitreoretinopathy: vaso-occlusive disease that is primarily found in the peripheral retina; findings include proliferation of peripheral vessels and falciform folds (which affect vision if involving the macula); typically affects young male patients, although carriers can exhibit peripheral vascular abnormalities

Goldmann-Favre syndrome: may be mistaken for XLRS because of the foveal schisis; drusen-like degenerative changes of the RPE are seen in the midperiphery and periphery

Retinal breaks: atrophic round holes are rarely associated with clinical RD; operculated retinal breaks are often associated with RD but are unlikely to be precursors; horseshoe tears (HST) are a classic pathologic feature; separation of the vitreous is associated with a higher risk for tears, particularly if a vitreous hemorrhage is present (risk is ≈10 times higher); retrospective study (219 patients) combined with a meta-analysis (1568 patients) by Coffee found that the incidence of RD with a symptomatic tear is 8.2%, and the incidence of late tears was 1.5%; retinal hemorrhages or new symptoms were risk factors for new or missed tears

Pathogenesis of RD: begins with vitreous separation, which likely starts around the macula, followed by the macula and optic nerve; retinal tears are more common in the periphery because the accumulation of tractional forces occurs in this area; persistent traction on a tear appears to be a necessary prerequisite for RD; shearing forces (ie, during eye movement) allow fluid to enter underneath the tear; over time, the specific gravity of subretinal fluid increases due to the accumulation of protein, which may explain why RDs in the superior region tend to progress more rapidly

Treatment considerations: retinal holes are sometimes treated; most retinal tears and RDs are treated; in general, treatment is not required if the patient is asymptomatic

Atrophic holes: typically asymptomatic and do not require treatment; present in 6% to 7% of patients >40 yr of age in clinical and histopathologic studies, and a histopathologic study by Foos found that 23% of cases were bilateral; study by Byer — followed 359 patients with asymptomatic retinal breaks for 1 to 18 yr and found that none of the patients developed RD in either eye; 77% of patients had atrophic holes (most found within areas of lattice degeneration), 14% had HSTs, and 9% had operculated tears; 18 patients had subclinical RDs, and only 3 of these enlarged slightly; none of the patients required treatment; study by Wilkinson — suggested that only symptomatic HSTs require treatment; 1974study by Davis — found that 9 out of 25 patients with symptomatic HSTs developed RDs; studies from Neumann, Hyams, and Byer — found that no patients with asymptomatic retinal tears developed RDs; predictors of future RD — symptomatic HST is the strongest precursor to RD and should be treated

Lattice degeneration: treatment may be considered in the fellow eye of an associated retinal break; study by Folk followed 296 patients with previous RD in one eye and lattice degeneration in the fellow eye for an average of 7.4 yr; treatment was not required in 39% of eyes, full treatment was given to 42%, and partial treatment was given to 19%; the rate of RD was 1.8% among treated fellow eyes and 5.1% among untreated fellow eyes; presence of myopia did not affect outcomes

Cases that do not require treatment: include operculated holes, retinoschisis, and most peripheral retinal abnormalities

Modifying factors: include occupational trauma risk, family history of genetic conditions (eg, Stickler syndrome), high myopia, and pseudophakia (although less relevant with modern cataract surgery)

Treatment of peripheral retinal breaks: speaker’s study of 173 eyes found that the risk for RD (with or without treatment) was higher in cases with a shorter duration, subretinal fluid, pseudophakia, or nonoperculated breaks; new break developed in 9% of treated eyes, and RD developed in 9% of treated eyes; epiretinal membranes occurred in ≈5% of eyes after treatment for a retinal break; several other studies yielded similar findings

Readings

Blindbaek S, Grauslund J. Prophylactic treatment of retinal breaks — a systematic review. Acta Ophthalmol. 2015;93(1):3-8; Coffee RE, Westfall AC, Davis GH, et al. Symptomatic posterior vitreous detachment and the incidence of delayed retinal breaks: case series and meta-analysis. Am J Ophthalmol. 2007 Sep;144(3):409-413; Diaz RI, Sigler EJ, Randolph JC, Rafieetary MR, Calzada JI. Spectral domain optical coherence tomography characteristics of white-without-pressure. Retina. 2014;34(5):1020-1021. doi:10.1097/IAE.0000000000000012; Foos R. Zonular traction tufts of the peripheral retina in cadaver eyes. Arch Ophthalmol. 1969;82:620-32; Ho T, Ho A. Long-term natural course of lattice degeneration of the retina in high myopic eyes– A ten-year long term study. Invest Ophthalmol Vis Sci. 2015 Jun;56(7 ):2965; Machemer R. The importance of fluid absorption, traction, intraocular currents, and chorioretinal scars in the therapy of rhegmatogenous retinal detachments. XLI Edward Jackson Memorial Lecture. Am J Ophthalmol. 1984;98(6):681–93; Molday RS, Kellner U, Weber BH. X-linked juvenile retinoschisis: clinical diagnosis, genetic analysis, and molecular mechanisms. Prog Retin Eye Res. 2012 May;31(3):195-212; Özateş S, Tekin K, Teke MY. Goldmann-Favre syndrome: case series. Turk J Ophthalmol. 2018 Feb;48(1):47-51; Rosenfeld PJ, Flynn HW Jr, McDonald HR, et al. Outcomes of vitreoretinal surgery in patients with X-linked retinoschisis. Ophthalmic Surg Lasers. 1998;29(3):190-197; Rutnin U, Schepens CL. Fundus appearance in normal eyes. 3. Peripheral degenerations. Am J Ophthalmol. 1967 Dec;64(6):1040-62; Sebag J. Anatomy and pathology of the vitreo-retinal interface. Eye (Lond). 1992;6 ( Pt 6):541-52; Shapiro MJ, Blair MP, Solinski MA, et al. The importance of early diagnosis of Stickler syndrome: Finding opportunities for preventing blindness. Taiwan J Ophthalmol. 2018 Oct-Dec;8(4):189-195; Spencer LM, Foos RY, Straatsma BR. Meridional folds, meridional complexes, and associated abnormalities of the peripheral retina. Am J Ophthalmol. 1970 Nov;70(5):679-714; Stehouwer M, Tan SH, van Leeuwen TG, et al. Senile retinoschisis versus retinal detachment, the additional value of peripheral retinal OCT scans (SL SCAN-1, Topcon). Acta Ophthalmol. 2014 May;92(3):221-227; Wilkinson CP. Interventions for asymptomatic retinal breaks and lattice degeneration for preventing retinal detachment. Cochrane Database Syst Rev. 2012;3(3):CD003170.

Disclosures

For this program, members of the faculty and planning committee reported nothing relevant to disclose.

Acknowledgements

Dr. Smiddy was recorded exclusively for Audio Digest on October 28, 2021, using teleconference software. Audio Digest thanks Dr. Smiddy for his cooperation in the production of this program.

CME/CE INFO

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Lecture ID:

OP600201

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

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