General mechanisms

Since idiopathic uveal effusion syndrome represents only a small percentage of ciliochoroidal effusions, it is important to discuss the general mechanisms of serous accumulation in the ciliary body and choroid. Most cases of ciliochoroidal effusion can be classified into one of the following pathophysiologic categories: (1) hydrodynamic; (2) inflammatory; (3) neoplastic; or (4) associated with abnormal sclera.³ Under physiologic conditions, a normal eye has equilibrium between the transmural hydrostatic pressure gradient, defined as the difference between the intravascular blood pressure and intraocular pressure, and the colloid osmotic pressure gradient of the choriocapillaris (Fig. 73.1). Albumin is the most abundant protein in the choroidal capillaries and is the primary driver of the colloid osmotic pressure. This pressure gradient draws fluid into blood vessels and maintains relative dehydration of the suprachoroidal space due to a low extravascular colloid concentration.⁴ Fenestrated capillaries of the choroid allow albumin to escape into the extravascular space. To maintain the colloid osmotic gradient, albumin leaves the choroid across the sclera and this transscleral protein flow is facilitated by intraocular pressure.^5–7

Fig. 73.1 In normal choroidal capillaries, the transmural hydrostatic pressure gradient is in equilibrium with the colloid osmotic pressure gradient. Colloids escaping the fenestrated capillaries move across the sclera by bulk flow, driven by intraocular pressure (IOP). BP, blood pressure.

(Courtesy of Biomedical Communications, University of Michigan.)

The fluid equilibrium across the layers of the choroid may be disturbed by several factors affecting one or more components of this intricate system.³ Ocular hypotony decreases the driving force for transscleral protein flow and increases the transmural hydrostatic pressure gradient. These changes then facilitate the accumulation of protein and fluid in the suprachoroidal space. Elevated uveal venous pressure increases the transmural hydrostatic pressure gradient and leads to increased fluid movement into the extravascular space. Vascular competence may be compromised by inflammation, which then increases capillary protein permeability and accumulation of protein in the extravascular space. This reduces the colloid osmotic pressure gradient and the absorption of extravascular fluid into the capillaries. Abnormal scleral composition or thickness may increase resistance to transscleral protein outflow and accumulation of protein-rich fluid in the suprachoroidal space. These alterations are more likely to affect the choroidal fluid dynamics when two or more are present simultaneously. Indeed, the creation of ciliochoroidal effusion in animal models requires experimental alteration of two or more pathophysiologic factors.^8,9

Idiopathic and nanophthalmic uveal effusion

In patients with uveal effusion syndrome or the closely related condition of nanophthalmos, abnormal sclera, referred to here as scleropathy, is the most likely primary ocular anomaly affecting choroidal fluid dynamics. In nanophthalmos, scleropathy is congenital in origin and associated with other ocular abnormalities. Acquired scleropathy may be secondary to a systemic disorder, such as the accumulation of amyloid in systemic amyloidosis or mucopolysaccharide in Hunter syndrome.^10,11 In uveal effusion syndrome, scleropathy appears to be secondary to the abnormal accumulation of glycosaminoglycan-like deposits and thickening of the sclera in the absence of any known systemic disorder.^12–14 Ward et al. reported that electron microscopy of excised sclera showed increased glycosaminoglycan-like deposits between the scleral fibers.¹⁴ In a following report, Forrester and colleagues performed histochemical studies on scleras excised from patients with uveal effusion syndrome and showed deposition of the glycosaminoglycan proteodermatan sulfate and a smaller amount of proteochondroitin sulfate, indicating a primary defect in scleral proteodermatan metabolism and representing a form of ocular mucopolysaccharidosis.¹² Histologic similarities between scleras isolated from eyes with uveal effusion syndrome and nanophthalmos were demonstrated by Uyama et al., who found disorganized scleral fibers and proteoglycan deposits in 6 nanophthalmic eyes and 11 nonnanophthalmic eyes with uveal effusion syndrome.¹³ As discussed above, abnormal scleral composition increases resistance to transscleral protein outflow, which in turn leads to the accumulation of protein in the extravascular space of the choroid and higher colloid osmotic pressure. This results in reduced movement of fluid from the suprachoroidal space into the choroidal capillaries and leads to serous ciliochoroidal effusion. In vitro experimental evidence is consistent with this model, as chondroitinase ABC digestion, which removes glycosaminoglycans, improves scleral transport in human cadaver eyes.¹⁵

Ciliochoroidal effusion and nonrhegmatogenous retinal detachment can be successfully treated in patients with uveal effusion syndrome by quadrantic partial-thickness sclerectomies.^16,17 The disappearance of serous fluid after partial-thickness sclerectomies is consistent with the hypothesis that abnormally thickened sclera prevents outflow of protein and suggests that the removal of excess extravascular protein may be improved by reducing scleral thickness and resistance. Under normal conditions, eyes with congenital or acquired scleropathies may have enough redundancy in choroidal protein transport mechanisms to achieve physiologic fluid equilibrium and dehydration of the suprachoroid. However, when choroidal fluid dynamics are further stressed by additional pathologic factors, such as compression of the vortex veins, these compensatory mechanisms may no longer be sufficient to overcome the effect of increased colloids in the suprachoroidal space, which may then lead to increased extravascular fluid retention and ciliochoroidal detachment.

Vortex vein compression was first suggested by Schaffer in 1975 as a possible mechanism of uveal effusion in nanophthalmic eyes following glaucoma filtration surgery.¹⁸ Relative obstruction of venous outflow secondary to compressed vortex veins may cause congestion of the choriocapillaris and alter the transmural hydrostatic pressure gradient, favoring increased retention of fluid in the suprachoroidal space. Brockhurst reported successful reattachment of the retina and resolution of ciliochoroidal effusion in nanophthalmic eyes after surgical decompression of the vortex veins.¹⁹ Additional evidence for the role of increased intravascular pressure secondary to reduced ocular venous drainage in uveal effusion was provided by Casswell and colleagues, who reported resolution of retinal detachment after vortex vein decompression in patients with uveal effusion syndrome.²⁰ As proposed by Gass, compression of the vortex veins by an abnormally thickened sclera may contribute to increased fluid retention and serous exudation in the choroid and ciliary body in uveal effusion syndrome.¹⁶

Ophthalmic ultrasound

B-scan ultrasound examination typically shows a smooth, thick, dome-shaped membrane with little aftermovement.²⁴ Ciliochoroidal effusion may be distinguished from retinal detachment by extension of the detachment anterior to the ora serrata. Highly bullous ciliochoroidal detachments may extend posteriorly and insert near the edge of the optic nerve. A-scan evaluation demonstrates a thick, 100% spike at tissue sensitivity, which at low sensitivity can often be seen to be double-peaked.²⁴ In early presentations of uveal effusion syndrome, the only evidence for ciliochoroidal effusion may be subtle degrees of supraciliary effusion on high-frequency ultrasound biomicroscopy. Diffuse, high-reflective thickening of the posterior choroid may be seen (Fig. 73.6). Low-reflective choroidal thickening should raise the suspicion for an infiltrative process secondary to an inflammatory or neoplastic condition.²⁴

Fig. 73.6 B-scan ultrasound of an eye with uveal effusion syndrome shows choroidal thickening and inferior nonrhegmatogenous retinal detachment.

Angiography and optical coherence tomography

The diagnostic value of fluorescein and indocyanine green angiography and optical coherence tomography is limited in uveal effusion syndrome and serves mostly to exclude other etiologies. Angiography may demonstrate a leopard-skin appearance of hyperfluorescence and hypofluorescence (Fig. 73.7). The presence of focal fluorescein leaks and focal pigment epithelial detachments should increase the suspicion for idiopathic central serous chorioretinopathy as the underlying diagnosis. Multiple pinpoint leaks may indicate the presence of an inflammatory or neoplastic choroidal infiltration. Indocyanine green angiography shows diffuse granular choroidal hyperfluorescence in the early phase, indicating marked hyperpermeability of the choroidal vessels.¹³ This choroidal hyperfluorescence persists into the late-phase angiogram and becomes more diffuse, demonstrating increased accumulation of fluid in the choroid. Spectral-domain optical coherence tomography may show focal thickening of the retinal pigment epithelium layer corresponding to the areas of leopard spots.²⁵

Fig. 73.7 Fluorescein angiogram of a patient with uveal effusion syndrome demonstrating leopard-skin appearance of hyperfluorescence and hypofluorescence.

Congenital and acquired scleropathies

As discussed above, congenital or acquired scleropathy with abnormal thickening of the sclera significantly alters the choroidal fluid dynamics and may cause uveal effusion, especially in the presence of other pathogenic factors such as vortex vein compression with reduced venous outflow and elevated uveal venous pressure. Uveal effusion syndrome and nanophthalmos can be considered in the same spectrum of diseases with a congenital primary scleral abnormality. Secondary scleral abnormalities are seen in association with systemic disorders, including amyloidosis or mucopolysaccharidosis.^10,11

Uveal effusion in patients with nanophthalmos is remarkably similar to that seen in the idiopathic uveal effusion syndrome. Nanophthalmos is a pure form of microphthalmia characterized by small eyes and extremely thick sclera with no other identifiable ocular or systemic abnormalities. The axial length is generally less than 20 mm and high hyperopia (> +7.00 D) is typical. Other findings include small corneal diameter, shallow anterior chamber, high lens-to-eye volume ratio, and strong predisposition to develop angle closure glaucoma.²⁶ Uveal effusion and nonrhegmatogenous retinal detachment may occur spontaneously and are frequently induced by intraocular surgery in nanophthalmic eyes.^26,27 The detection of nanophthalmos is important prior to any planned intraocular procedure since prophylactic use of sclerectomies may prevent significant postoperative complications secondary to uveal effusion.

Hydrodynamic effusions

Hydrodynamic factors associated with ciliochoroidal effusion include ocular hypotony, elevated uveal venous pressure, and malignant hypertension. Long-standing low intraocular pressure induces uveal effusion and may in turn be worsened by ciliary body detachment. The most common reason for hypotony is glaucoma filtering or drainage device surgery, especially in the early postoperative period. Resuturing the scleral flap, scleral patch grafting, autologous blood injection, and other methods have been described in the literature to reverse postoperative hypotony.^28–30 Hypotony and uveal effusion complicating anterior-segment surgery are usually secondary to a wound leak or inadvertent filtering bleb. Other ocular disorders that may lead to hypotony and secondary ciliochoroidal effusion include cyclodialysis, penetrating ocular trauma, rhegmatogenous retinal detachment, and ciliary body dysfunction.

Elevated uveal venous pressure and increased transudation from choroidal vessels may be seen in the setting of carotid-cavernous sinus fistula or dural arteriovenous fistulas. When an intracranial fistula is suspected in a patient with uveal effusion, nonrhegmatogenous retinal detachment, and other associated findings, neuroimaging should be obtained. Patients with idiopathic prominent episcleral vessels or Sturge–Weber syndrome have elevated episcleral venous pressure and likely secondary increase in choriocapillaris pressure, which predisposes them to a higher risk of significant ciliochoroidal effusion during intraocular surgery when the intraocular pressure drops to zero.³¹ Compression of the vortex veins and reduction of ocular venous outflow may lead to uveal effusion after scleral buckling surgery.

Malignant hypertension secondary to severe renal disease or pregnancy may lead to ciliochoroidal effusion and nonrhegmatogenous retinal detachment, which usually resolve with blood pressure control.

Inflammatory factors

In addition to causing hypotony, penetrating trauma may induce marked intraocular inflammation, which leads to increased vascular permeability. Chronic low-grade inflammation with increased permeability of the choriocapillaris may also be seen after intraocular surgery. Transient vascular leakage and serous ciliochoroidal fluid accumulation may be seen after thermal injury from panretinal photocoagulation or transscleral cryotherapy. Inflammation of the uveal tract secondary to autoimmune or infectious etiologies may be complicated by ciliochoroidal effusion and nonrhegmatogenous retinal detachment. A uveitic syndrome is usually suspected in these patients based on other ocular findings. A painful or red eye in a patient with uveal effusion may be secondary to scleritis, idiopathic orbital inflammation, or orbital cellulitis. A buckle infection should always be in the differential diagnosis of uveal effusion in a patient with scleral inflammation after scleral buckling surgery.

Neoplastic effusions

Choroidal metastatic tumors or malignant melanoma may infrequently present with ciliochoroidal effusion and nonrhegmatogenous retinal detachment. The diagnosis may only be apparent after an ophthalmic ultrasound in cases with extensive choroidal and subretinal fluid accumulation. In addition to solid tumors of the eye, neoplastic infiltrations and secondary uveal thickening may cause nonrhegmatogenous retinal detachment and occasional serous uveal effusion in lymphoproliferative disorders or melanocytic proliferation.

Scleral thinning procedures

Gass first described sclerectomy with sclerostomy for the treatment of uveal effusion syndrome in 1983.¹⁶ The idea of using this procedure in patients with uveal effusion syndrome arose after an unsuccessful attempt at vortex vein decompression in another patient. Gass operated on both eyes of a patient with thick sclera and uveal effusion and amputated or ruptured the vortex veins during attempted decompression. Despite the occurrence of suprachoroidal hemorrhage in both eyes, ciliochoroidal and nonrhegmatogenous detachment resolved in both eyes postoperatively. This observation led him to hypothesize that the excision of large scleral flaps at the sites of vortex veins was responsible for the successful outcome. To test this hypothesis, he performed quadrantic partial-thickness sclerectomies and sclerostomies without vortex vein decompression or drainage of subretinal fluid in both eyes of a patient with long-standing uveal effusion and bullous nonrhegmatogenous retinal detachment. Complete resolution of ciliochoroidal and subretinal fluid occurred 10–12 weeks after surgery.¹⁶ In 1990, Johnson and Gass expanded on this initial result in a retrospective study of 23 eyes of 20 patients with uveal effusion syndrome who underwent a scleral-thinning procedure without vortex vein decompression.¹⁷ The investigators observed complete resolution of subretinal and supraciliochoroidal fluid in 96% of eyes after one or two procedures. The mean time for resolution of uveal effusion and nonrhegmatogenous retinal detachment was 2.4 months. Other investigators reported similar results using scleral-thinning procedures for treatment of uveal effusion and nonrhegmatogenous retinal detachment associated with Hunter syndrome, nanophthalmos, and uveal effusion syndrome.^{11,13,20,32,33}

The surgical procedure for scleral thinning involves the creation of 5 × 7 mm, one-half to two-thirds thickness sclerectomies in each quadrant, centered 1–2 mm anterior to the equator and placed outside the meridian of each vortex vein to avoid its intrascleral course (Fig. 73.8).^16,17 The long axis of the sclerectomy is oriented circumferentially. An approximately 2-mm linear sclerostomy may be created in the center of each sclerectomy bed and enlarged with a 1–2-mm scleral punch. Similar scleral-thinning techniques have been reported by others treating nanophthalmic or idiopathic uveal effusion.^13,34

Fig. 73.8 Scleral-thinning procedure for uveal effusion syndrome. Borders of the sclerectomy are outlined with partial-thickness scleral incisions (top left). One-half to two-thirds thickness lamellar scleral dissection is performed (top right), creating a scleral window (bottom left) and an excised section of abnormally thick sclera (bottom right).

Pars plana vitrectomy

The extent of visual improvement after scleral-thinning procedures may be limited by photoreceptor and retinal pigment epithelial damage secondary to chronic retinal detachment. In the series reported by Johnson and Gass, visual acuity improved by two or more Snellen lines in 56% of eyes, remained stable in 35% of eyes, and worsened in 9% of eyes.¹⁷ Overall visual acuity was 20/400 or better in 96% of eyes and 20/40 or better in 35% of eyes. Among the 12 of 23 eyes whose final visual acuity was worse than 20/40, the primary vision-limiting factor was atrophic photoreceptor and retinal pigment epithelial damage due to chronic retinal detachment. The mean time for retinal reattachment following scleral-thinning surgery in this series was 2.4 months. To facilitate rapid retinal reattachment and prevent ongoing damage to photoreceptors and the retinal pigment epithelium, Schneiderman and Johnson performed pars plana vitrectomy and internal drainage of subretinal fluid at the time of quadrantic partial-thickness sclerectomies in a 73-year-old man with uveal effusion syndrome and total retinal detachment.³⁵ This patient’s vision improved from hand motions to 20/70 1 year postoperatively. This combined approach of sclerectomies and pars plana vitrectomy for macula-off nonrhegmatogenous retinal detachment in uveal effusion syndrome allows immediate approximation of the photoreceptors and the retinal pigment epithelium and prevents further photoreceptor cell death. An alternative approach is external drainage of the subretinal fluid,²² which presents significant risk of subretinal hemorrhage, profound ocular hypotony, and difficulty accessing the posteriorly shifting subretinal fluid.

Vortex vein decompression

In 1980, Brockhurst reported successful use of scleral-thinning procedure with vortex vein decompression in the treatment of nanophthalmic ciliochoroidal effusion.¹⁹ He described the isolation of the intrascleral portion of the vortex vein and decompressing all four veins. Since scleral-thinning procedures alone are successful in the treatment of uveal effusion syndrome, vortex vein decompression for the treatment of ciliochoroidal effusion in uveal effusion syndrome or nanophthalmos is no longer performed by most vitreoretinal surgeons.

Fluorescein angiography

Fluorescein angiography is useful in demonstrating chorioretinal folds, especially in mild cases with a normal-appearing fundus examination. In the initial stages of hypotony, fluorescein angiography demonstrates an irregular increase in background choroidal fluorescence corresponding to the crest of the choroidal folds (Fig. 73.10). This produces hyperfluorescent streaks that may be seen in the early arterial phase. The hyperfluorescence of these streaks are multifactorial: (1) thinning of the retinal pigment epithelium on the crest of the folds; (2) pooling of the choroidal fluorescein under the crest; and (3) shorter course of the incident blue and reflected yellow-green light during angiography. The troughs of the folds are occupied by compressed retinal pigment epithelial cells, which reduce the transmission of the background choroidal fluorescence and cause hypofluorescence on angiography. Leakage of fluorescein may be seen in the capillaries of the optic nerve and there is typically no leakage in the retinal capillaries.⁴³ In long-standing hypotony, angiography may show permanent alterations in the retinal pigment epithelium. The chorioretinal folds may be differentiated from the folds of the neurosensory retina, which do not alter the background fluorescence.

Fig. 73.10 Fluorescein angiogram in hypotony maculopathy demonstrates hyperfluorescent streaks corresponding to the crest of the chorioretinal folds.

Ocular ultrasound

B-scan ultrasonography typically shows flattening and thickening of the sclera and choroid in the posterior pole⁴⁴ (Fig. 73.11). Anterior-segment evaluation with ultrasound biomicroscopy may be useful for the identification of the underlying etiology of hypotony. The presence of a cyclodialysis cleft or anterior ciliary detachment may only be apparent on ultrasound biomicroscopy.^45,46

Fig. 73.11 B-scan ultrasonography in a patient with low intraocular pressure showing characteristic flattening and thickening of the sclera and choroid in the posterior pole.

Optical coherence tomography

In patients with low intraocular pressure and reduced visual acuity, optical coherence tomography imaging of the posterior pole can help to demonstrate subtle chorioretinal folds of the macula that may otherwise be difficult to detect on biomicroscopy^47–49 (Fig. 73.12). High-resolution optical coherence tomography may detect chorioretinal folding in early hypotony, which may not show any changes in the background choroidal fluorescence during fluorescein angiography.⁴⁸ However, the clinical significance of subtle chorioretinal folds detected only by optical coherence tomography in a patient with unchanged vision is unclear. Optical coherence tomography in a patient with symptomatic hypotony maculopathy and stereotypical biomicroscopic findings typically shows prominent chorioretinal folds (Fig. 73.12).

Fig. 73.12 High-resolution optical coherence tomography may demonstrate subtle (top panel) or prominent (bottom panel) chorioretinal folding in hypotony maculopathy.

Hypotony

The reduction of intraocular pressure may be secondary to decreased aqueous production or increased aqueous outflow. In most cases, both a reduction in aqueous production and an increase in aqueous outflow are present in a hypotonous eye. Table 73.2 lists various etiologies of decreased intraocular pressure, some of which will be briefly discussed below.

Table 73.2 Causes of hypotony

Decreased aqueous production

Reduced aqueous production is an uncommon etiology of hypotony. The factors that lead to decreased aqueous production may be inflammatory, vascular, or structural. Ciliary body inflammation may compromise the production of aqueous in patients with uveitis. Severe intraocular inflammation in the immediate postoperative period following intraocular surgery may decrease aqueous secretion. Trauma may be associated with significant iridocyclitis and hypotony, which may be worsened by increased aqueous outflow due to a cyclodialysis cleft or globe rupture. Decreased ocular perfusion in patients with vasculitis or arterial occlusion may cause ciliary body ischemia. Other causes of decreased aqueous production include ciliary body detachment secondary to ciliochoroidal effusion, trauma, or proliferative vitreoretinopathy.

Increased aqueous outflow

When the aqueous production is no longer sufficient to match the increased outflow, hypotony develops. Most cases of ocular hypotony are secondary to increased aqueous outflow. Under physiologic conditions, the aqueous leaves the eye primarily through the trabecular meshwork and Schlemm’s canal in a pressure-dependent manner, with much smaller amounts exiting through uveoscleral outflow. Several factors may increase aqueous outflow, including wound leak after anterior-segment surgery and excessive aqueous filtration after glaucoma filtering or drainage device surgery. After the introduction of antimetabolites in glaucoma-filtering procedures, the incidence of hypotony increased.³⁹ Antimetabolites inhibit subconjunctival healing and scarring, which would otherwise limit the overfiltration rate. With the introduction of sutureless small-gauge vitrectomy technology, vitreoretinal surgeons encounter ocular hypotony with increasing frequency in their postoperative patients.⁵⁰ Ocular trauma may be associated with scleral rupture and wound leak. Postoperative or traumatic cyclodialysis creates a free communication between the anterior chamber and the suprachoroidal space, increasing the uveoscleral outflow.

Mechanism of maculopathy

Chorioretinal folds form in the hypotonous eye due to scleral shrinkage and reduction of the inner surface area of the sclera. This loss of surface area then leads to folding of the inner portion of choroid and the outer retina.^51–54 Maculopathy develops when the neurosensory retina is thrown into a series of stellate folds around the center of the fovea. This central stellate retinal wrinkling is caused by the thickened posterior scleral wall and the choroid displacing the normally thick retina surrounding the thin foveola.⁴³ The folding of the neurosensory retina is the primary cause of vision loss in hypotony maculopathy. The risk of hypotony maculopathy is highest in young myopic patients, and this may indicate that the sclera is more vulnerable to swelling and contraction in young patients.

Mechanism of optic disc edema

Reduced intraocular pressure may lead to broad areas of choroidal swelling and retinal folding around the optic nerve and this may cause disc edema.⁴³ Another proposed mechanism is the anterior bowing of the lamina cribrosa and constriction of axonal bundles in the lamina scleralis, causing reduced orthograde and retrograde axoplasmic transport and swelling of the optic nerve.⁵⁵ Disc edema may be less impressive in eyes with pre-existing optic nerve disease and loss of axons.

Idiopathic chorioretinal folds

Horizontal macular chorioretinal folds as well as folds radiating from the optic nerve may be seen in young hyperopic patients on routine evaluation.^52,56 These idiopathic chorioretinal folds are usually confined to the area around the macula and optic nerve, but may at times involve most of the posterior pole. Patients usually do not report any visual dysfunction. The appearance of the folds is usually symmetric in both eyes, but may occasionally be seen unilaterally. As the name indicates, the etiology of these chorioretinal folds is unknown and may be secondary to the shrinkage of the fibrous tunic of the eye after an inflammatory process during early years of life.⁴³

Retrobulbar mass lesions

Any space-occupying mass in the orbit may cause scleral edema, choroidal congestion, and chorioretinal folds.^57,58 A mass in the extraconal space may induce astigmatism, whereas intraconal location of a tumor may lead to acquired hyperopia.⁵⁷ Both benign and malignant tumors have been reported to present with chorioretinal folds.

Scleral inflammation

Scleral inflammation with edema, thickening, and choroidal congestion may lead to the development of chorioretinal folds. Thyroid eye disease, idiopathic orbital inflammation, and other autoimmune or infectious uveitic diseases presenting with scleritis may have associated chorioretinal folds.^43,59,60

Scleral buckle

Thickening of the sclera in the posterior slope of a scleral buckle may cause occasional chorioretinal folds in patients who underwent rhegmatogenous retinal detachment repair.

Choroidal tumors

Malignant melanoma or metastatic lesions of the choroid may cause vascular congestion, choroidal edema, and scleral thickening, leading to chorioretinal folds surrounding the tumor.⁴³

Choroidal neovascularization

Spontaneous or laser-induced contraction of subretinal pigment epithelial choroidal neovascular membrane may induce the formation of chorioretinal folds that radiate away from the membrane.⁶¹

Focal chorioretinal scars

Focal scars of the choroid and the retina may sometimes cause contraction and induce chorioretinal folds radiating towards the center of the scar.⁶²

Optic nerve head disorders

Idiopathic intracranial hypertension and papilledema may be associated with chorioretinal folds. These folds are usually horizontal in the macula and converge on the nasal side of the swollen optic nerve.^63,64 Chorioretinal folds have also been seen in patients with unexplained optic atrophy.⁶⁵ In some patients with increased intracranial pressure, chorioretinal folds may present in the absence of any detectable papilledema and a lumbar puncture with an opening pressure may need to be performed to rule out idiopathic intracranial hypertension.⁶⁶

Retinal folds

Retinal folds may be mistaken for chorioretinal folds in some eyes. Usually, folds of the neurosensory retina are narrow and seen radiating away from a focal inner retinal contraction caused by macular pucker or outer retinal contraction secondary to a chorioretinal scar (Fig. 73.13).⁴³ Fluorescein angiography is helpful in differentiating retinal folds from chorioretinal folds, since folds of the neurosensory retina do not change the fluorescence pattern and are not seen on angiography.

Fig. 73.13 Red-free photo of the posterior pole (top panel) and high-resolution optical coherence tomography (bottom panel) demonstrate fine, subtle retinal folds associated with an epiretinal membrane. Fluorescein angiogram shows no fluorescence changes associated with these folds (middle panel).