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mercredi 4 septembre 2019

Childhood Retinal Detachment


 Introduction
Retinal detachment in is uncommon in childhood,accounting for between 1.7% and 5.7% of all retinal detachment [4, 34]. In a study of 45,000 army recruits,it has been calculated that the age-related annual incidence of retinal detachment in patients aged 10–19years is 2.9 per 100,000 [32]. Young children and infants do not complain ofvisual loss and retinal detachment in children frequently presents late or with fellow eye involvement;22–38% may present with proliferative vitreoretinopathy of grade C or D [2]. Many studies have identified trauma and myopia as predisposing causes ofretinal detachment in children. Emphasis is now also placed on the importance of inherited disorders,such as Stickler syndrome,which is associated with a high risk of giant retinal tear and the recognition that myopia,especially congenital myopia,is likely to be an indication ofother ophthalmic or systemic abnormalities.Retinal detachment may complicate developmental abnormalities, including colobomata, congenital cataract, congenital glaucoma and retinopathy of prematurity. Congenital retinal detachment,or congenital nonattachment of the retina,is now recognized as part of the spectrum of vitreoretinal dysplasia. Retinoblastoma or other tumours may give rise to a “solid”detachment.Retinal detachment may also result from intraocular infection or inflammation. When considering the aetiology, family history and examination ofrelatives and,in particular,examination of the vitreous can give valuable information. Children may need careful examination under anaesthesia to determine
Childhood Retinal Detachment Arabella V.Poulson,Martin P.Snead
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∑ Retinal detachment in childhood is uncommon and has a different range of aetiologies from adult retinal detachment ∑ It often presents late or with involvement of the fellow eye ∑ High myopia,particularly if congenital,usually indicates an underlying abnormality ∑ Retinal dialysis is not associated with posterior vitreous detachment ∑ Giant retinal tear is usually associated with abnormal gel and an underlying hereditary vitreoretinopathy and should be differentiated from dialysis because it has a different prognosis and requires different management ∑ Stickler syndrome is the commonest inherited cause of retinal detachment with a lifetime risk of more than 60% ∑ Stickler syndrome may have no systemic features and can be diagnosed purely on the vitreous phenotype ∑ Many causes of retinal detachment in childhood are associated with an underlying developmental abnormality which may limit the prognosis for good vision ∑ There is a real case for offering prophylactic treatment to prevent retinal detachment where there is a familial risk of giant retinal tear Core Messages
the cause ofthe retinal detachment and whether it is rhegmatogenous,tractional or exudative. The range ofunderlying causes ofretinal detachment in children is different from that in adults.The association with complex intraocular pathology and the additional problems of amblyopia in young children means that they often present a formidable challenge to treatment.Where possible,therefore,serious consideration should be given to prophylaxis against retinal detachment.
12.2 Trauma
Trauma has been reported as the cause in 27–51% of cases of childhood retinal detachment [47].Traumatic retinal detachment is seen most commonly in older children and is usually caused by blunt trauma. Retinal tears may be found in approximately 2–5% [9]. Penetrating injuries and retained intraocular foreign bodies are less frequent causes but are associated with severe proliferative vitreoretinopathy.
12.2.1 Blunt Ocular Trauma
Retinal detachment due to blunt trauma is almost always rhegmatogenous and most commonly caused by a disinsertion at the ora serra
ta (dialysis) (Fig.12.1A), usually occurring in older children.Bilateral retinal detachment due to traumatic dialysis has been described as a rare presenting feature of nonaccidental injury [14]. Sudden antero-posterior compression associated with a corresponding coronal expansion typically causes avulsion of the pars plana epithelium,which can be seen as a characteristic irregular ribbon within the vitreous cavity (Fig.12.1B). The superior quadrant is more often involved in contrast to the usual lower temporal quadrant involvement in nontraumatic dialysis [17, 33]. The disinsertion may involve more than 90° of the circumference and superficially resemble a giant retinal tear. However, the vitreous gel remains attached to the posterior flap so that there is no independent mobility characteristic ofa giant retinal tear.Further distinguishing features are the absence of radial extensions,which frequently occur at the apices of giant retinal tears and the normal compact healthy vitreous gel architecture.Giant tears in childhood are typically associated with abnormal gel and inherited vitreoretinopathies. Recruitment of subretinal fluid is typically slow in a dialysis so that unless the ora serrata is routinely examined after blunt trauma,the diagnosis may be delayed by several weeks until the macular becomes involved [22]. Dialyses respond well to repair with scleral buckling techniques. Ragged impact necrosis breaks account for about one-fifth of retinal breaks seen in blunt
192 Chapter 12 Childhood Retinal Detachment
Fig.12.1. a Retinal detachment due to traumatic retinal dialysis.bAvulsed pars plana epithelium in the vitreous cavity following blunt trauma
a b
trauma [22].Retinal vessel and retinal pigment epithelial disruption may be confirmed on fundus fluorescein angiography. The retinal detachment usually presents soon after the injury. These breaks are often large, irregular and posterior to the equator and therefore need an internal approach with vitrectomy for effective repair. Giant retinal tears account for a minority of retinal breaks due to blunt trauma. They respond well to vitrectomy and internal tamponade, although the visual prognosis is often limited by associated ocular damage.
12.2.2 Penetrating Ocular Trauma
Retinal perforation or incarceration from penetrating trauma rarely causes acute rhegmatogenous retinal detachment.The associated corneoscleral wound provides access for extrinsic fibroblasts so that combined tractional and rhegmatogenous retinal detachment presents sometimes much later. Vitrectomy and internal tamponade with or without relieving retinectomy may be required as severe proliferative vitreoretinopathy commonly occurs.Traumatic giant retinal tears have been reported to occur in 22% of open globe injuries [34].
12.3 Nontraumatic Retinal Dialysis
Nontraumatic retinal dialysis (Fig.12.2) accounts for approximately 10% ofall juvenile retinal detachment [17,43].The male-to-female ratio is 3:2 [43] and the majority of patients are hypermetropic or emmetropic [17,33,36].In 97% of cases,the dialysis affects the inferotemporal quadrant but multiple dialyses occur in one-third and 37% may be bilateral [43].Detachments associated with dialyses progress slowly, have a low incidence of PVR and characteristically present either as an incidental finding or when the macula becomes detached. They can be managed routinely with buckling techniques
and the use of a small (typically 3-mm) circumferential sponge reduces the likelihood of postoperative motility problems. Although the anatomical success rate of surgery is high,visual recovery may remain poor if there has been chronic macular involvement. Examination of the fellow eye under anaesthesia is also important,as retinal dialysis may be bilateral and oral abnormalities,in the form ofa “frill”or flat dialysis,are found in the fellow eye in up to 30% of cases.
Summary for the Clinician ∑ Retinal dialysis – May or may not be caused by trauma – Is not associated with posterior vitreous detachment ∑ Giant retinal tear – Is usually associated with abnormal gel and an underlying hereditary vitreoretinopathy – Should be differentiated from dialysis because it has a different prognosis and requires different management – Results from posterior vitreous detachment and can be recognized by independent mobility of the posterior flap and may develop radial extensions because of this – Can involve less than 90°of circumference
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Fig.12.2. Retinal detachment due to nontraumatic retinal dialysis
12.4 Familial Retinal Detachment
Rhegmatogenous retinal detachment can occur in a number ofinherited disorders (see Table12.1), the most common being the Stickler syndromes due to mutations in the genes for type II and type XI collagens,constituents of both vitreous and cartilage.High myopia and retinal detachment are also seen in Marfan syndrome, Ehlers–Danlos syndrome,Smith–Magenis syndrome, Kniest syndrome and spondyloepiphyseal dysplasia congenita. The detachments are often complex and frequently caused by giant retinal tear. In familial exudative vitreoretinopathy (FEVR),Norrie disease and incontinentia pigmenti,there is an underlying retino
vascular abnormality and tractional retinal detachment.Rarely retinal detachment may complicate juvenile X-linked retinoschisis.
12.4.1 The Stickler Syndromes
12.4.1.1 Type 1 Stickler Syndrome
Stickler initially described a family with a dominantly inherited pattern of high myopia,a high incidence of retinal detachment and abnormal epiphyseal development with premature degenerative changes in various joints. Subsequent analysis of this and other families linked the disorder to COL2A1,the gene for type II col
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Table12.1. Inherited disorders associated with retinal detachment
Disorder Symbol Locus Gene Protein McKusick No
Stickler syndrome type 1 STL1 12q13.2 COL2A1 Type II collagen 108300 Stickler syndrome type 2 STL2 1p21 COL11A1 Type XI collagen 604841 Kniest dysplasia – 12q13.11–13.2 COL2A1 Type II collagen 156550 Spondyloepiphyseal SEDC 12q13.11–13.2 COL2A1 Type II collagen 183900 dysplasia congenita Spondyloepimetaphyseal SMED 12q13.11–13.2 COL2A1 Type II collagen 184250 dysplasia (Strudwick type) VPEDa – 12q13.11–13.2 COL2A1 Type II collagen – Ehlers–Danlos type VI EDS VI 1p36.3-p36.2 PLOD1 lysine 225400 hydroxylase Marfan syndrome MFS 15q21.1 FBN1 Fibrillin 154700 Wagner vitreoretinopathy WGN1 5q14.3 – – 143200 Smith–Magenis SMS 17p11.2 RAI1 – 182290 Norrie’s disease ND Xp11.4 NDP Norrin 310600 Familial exudative vitreo- EVR1 11q13–23 FZD4 Frizzled-4 receptor 133780 retinopathy (FEVR) EVR1 11q13.4 LRP5 LRP5b 603506 EVR2 Xp11.4 NDP Norrin 310600 EVR3 11p12–13 – – 605750 Incontinentia pigmenti IP2 Xq28 NEMO – 308300 Juvenile X-linked RS1 Xp22.2–22.1 RS – 312700 retinoschisis Knobloch syndrome KNO 21q22.3 COL18A1 Type XVIII 267750 collagen
a Vitreoretinopathy associated with phalangeal epiphyseal dysplasia,bLRP5 low-density lipoprotein receptor-5
lagen on chromosome 12. Stickler syndrome is therefore on the mild end of a spectrum of chondrodysplasias,which include spondyloepiphyseal dysplasia congenita, spondyloepimetaphyseal dysplasia and Kniest dysplasia.
Ophthalmic Features
Eighty percent of patients with type 1 Stickler syndrome are myopic.The myopia is congenital and usually of high degree. The 20% who are emmetropic,or even hypermetropic,do in fact have an increased axial length which is refractively compensated by cornea plana. The term “congenital megalophthalmos” or “cryptomyopia” has been used to encompass both states. Lens opacities, often wedge-shaped cortical opacities peculiar to Stickler syndrome,may be seen.Pigmented radial paravascular lattice is a characteristic feature but the fundus appearances can be deceptively normal. The vitreous phenotype, however, is pathognomonic. A vestigial amount of gel behind the lens is bordered by a distinct folded membrane, termed the membranous or type 1 vitreous anomaly (Fig.12.3A) [39]. This membrane is congenital and should not be confused with the posterior hyaloid membrane, which differs in its position, its movement and the degree of surface crinkling.The lifetime risk ofretinal detachment, particularly due to giant retinal tear (Fig.12.3B,C),and which can occur at any age,is at least 60% [38].
Facial Features
Classically,patients have a flat midface with a depressed nasal bridge, anteverted nares, and a small, recessed chin. These findings are usually most evident in children,becoming less obvious in adults.Facialfeatures are so variable that in isolation they are unreliablefor making a diagnosis. Many patients have some degreeofmidline clefting ranging from the extreme ofthe Pierre-Robin sequence, through clefting of the hard or soft palate,to the mildest manifestation ofbifiduvula.
Hearing
Patients with Stickler syndrome may suffer hearing difficulties for two reasons.Firstly,the association with cleft and higharched palate leads to an increased incidence of serous otitis mediacausing a conductive hearing deficit.Insome patients, a mild conductive element persists,despite treatment, because of ossicle defects or tympanic membrane abnormalities.Secondly,there can be an associated high tone sensorineural hearing loss that may be so subtle that many patients are unaware of the deficit. Baseline audiometry therefore has an important diagnostic role to reveal subtle asymptomatic high tone loss.
Joints
Children with Stickler syndrome classically have hypermobile joints (Fig.12.4).Joint mobility can be assessed objectively using the Beighton scoring system to allow comparison with anage,sex,and race matched population.
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Fig.12.3. aType 1 (membranous) vitreous anomaly (arrow) seen in type 1 Stickler syndrome.bGiant retinal tear with radial extensions.cTotal retinal detachment due to 360°giant retinal tear
a b c
With increasing age, the hypermobility is lost and a degenerative arthropathy of variable severity may develop by the third or fourth decade. Typical radiological changes show irregularity of articular contour and loss of joint space. By middle age, some patients require joint replacement surgeryfor hips or knees.
Other Features
Patients are of normal height and often have slender extremities and long fingers.They are of normal intellect.Early reports of increased mitral valve prolapse have not been substantiated by recent studies which show that it is no more frequent than in the general population [1].
Ocular Only Stickler Syndrome
A subgroup of type 1 Stickler syndrome has been identified without systemic skeletal or auditory involvement.One mechanism explaining this is a mutation in exon 2 of the COL2A1 gene. Exon 2 is principally expressed in the eye and spliced out of cartilage,resulting in a predominantly ocular form of Stickler syndrome with minimal or absent systemic involvement [27]. Because of the absent systemic features, this group are at particular high risk ofmissed diagnosis, emphasising the importance of the ophthalmic examination in the diagnosis ofStickler syndrome.
12.4.1.2 Type 2 Stickler Syndrome
Although most patients with Stickler syndrome were found to have the type 1 vitreous phenotype, it became clear that a minority of pedigrees had the same classical systemic features and the same risk ofretinal detachment but had a different vitreous phenotype. The vitreous was also highly abnormal but instead of the classical membranous anomaly, sparse, irregularly thickened, “beaded” fibrils were seen throughout an otherwise empty-looking gel (type 2 vitreous phenotype).Linkage to COL2A1 was excluded. Mutations in the gene encoding the a1 chain of type XI collagen (COL11A1) on chromosome 1 have been found in seven families [23, 31, 40] and these are, to date, the only mutations associated with the type 2vitreous phenotype. These pedigrees have a similarly high risk of detachment and giant retinal tear but appear to have a higher prevalence of sensorineural deafness than the type 1 Stickler families [26].
12.4.1.3 Molecular Genetics
Types II and XI are fibrillar collagens and are found in both vitreous and cartilage.Collagens consist of three polypeptide chains (a chains), which are folded into triple helical molecules to form fibrils.Collagen II is a homotrimer,each a chain being the product of the COL2A1 gene. Collagen XI is a heterotrimer with each achain being the product of a different gene. In vitreous, the three genes are COL11A1, COL5A2 and COL2A1 and in cartilage COL11A2 on chromosome 6 replaces COL5A2.Mutations ofCOL11A2 may thus cause systemic features of Stickler syndrome without eye involvement (type 3 Stickler syndrome). The difference in severity of clinical features between the type II collagenopathies can be explained in part by the fact that in Stickler syndrome many different mutations in COL2A1 cause premature termination codons.These result in haploinsufficiency where normal, but half-quantity, collagen is produced. Mutations in the more severe conditions have a dominant
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Fig.12.4. Joint hypermobility in Stickler syndrome
negative effect,where normal and mutant collagen are available to co-assemble, with consequent adverse effect on trimer assembly. Some families have neither ofthe two vitreoretinal phenotypes and linkage to the known loci has been excluded so there is at least one further locus to be discovered.
12.4.1.4 Management
Once the diagnosis of Stickler syndrome has been established, a coordinated multidisciplinary approach may be needed to manage myopia and retinal detachment,combined conductive and sensorineuraldeafness,cleft palate and joint problems.Although intelligenceis normal, patients ofschool age may face considerable educationaldifficulties because of combined visual,hearing and speech impairment.Prophylactic retinopexy should be offered to reduce the risk of retinal detachment [38] and because of the lifetime risk of detachment,all patients require long-term follow-up. Parents and other siblings should also be examined so that affected members of the family are identified,offered prophylaxis and genetic advice.
Summary for the Clinician ∑ The Stickler syndromes are dominantly inherited disorders of collagen connective tissue and the commonest inherited cause of rhegmatogenous retinal detachment in childhood ∑ Type 1 Stickler syndrome is caused by mutations in COL2A1,the gene for type II collagen ∑ The diagnosis can reliably be made by examination of the vitreous phenotype ∑ Type 2 Stickler syndrome is caused by mutations in COL11A1,a gene for type XI collagen and has a different “beaded” vitreous phenotype ∑ Other variable features include cleft palate, deafness and arthropathy ∑ The risk of retinal detachment is extremely high and frequently due to giant retinal tear ∑ The diagnosis should be considered in: – Neonates with Pierre-Robin sequence or midline cleft
– Infantswith spondyloepiphyseal dysplasia associated with myopia or deafness – Patients with a family history of rhegmatogenous retinal detachment – Sporadic cases of retinal detachment associated with jointhypermobility, midline clefting,ordeafness.
12.4.2 Kniest Syndrome
Kniest syndrome is an autosomal dominant disorder that shares many similarities with Stickler syndrome. Mutations are found in the same gene as for Type 1 Stickler syndrome (COL2A1), but result in dominant-negative effects rather than haploinsufficiency with consequently more severe arthropathy.It typically presents at birth with shortened trunk and limbs, congenital megalophthalmos and flattened nasal bridge.The joints are often large at birth and the fingers long and knobbly.Motor milestones can be delayed because of joint deformities and muscle atrophy may result from disuse. Both conductive and sensorineural hearing loss may be present as with the Stickler syndromes.The intellect is normal and myopia, retinal detachment and giant retinal tear are the major ophthalmic complications.
12.4.3 Spondyloepiphyseal Dysplasia Congenita
Spondyloepiphyseal dysplasia congenita (SEDC) presents at birth with shortening of the trunk and to a lesser extent the extremities.It is inherited as an autosomal dominant disorder and characteristically results from dominant-negative mutations in the gene for type II collagen (COL2A1). Patients classically develop a barrelshaped chest associated with an exaggerated lumbar lordosis which may compromise respiratory function.Odontoid hypoplasia may be present predisposing to cervico-medullary instability and imaging of the cervical spine should be considered prior to general anaesthesia. The limb shortening is disproportionate, affecting mainly the proximal limbs with hands and feet
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appearing relatively normal.Myopia,retinal detachment and giant retinal tear are the major ophthalmic complications and,as with the other type II collagenopathies, both conductive and sensorineural hearing loss may be present.
12.4.4 Spondyloepimetaphyseal Dysplasia (Strudwick Type)
Spondyloepimetaphyseal dysplasia (SEMD) also forms part ofthe clinical spectrum ofdominantly inherited type II collagenopathies. The features include severe dwarfism,pectus carinatum and scoliosis which are usually marked. Cleft palate and retinal detachment are frequently associated, as with SEDC. Disproportionately short limbs and delayed epiphyseal maturation are present at birth.Radiologically,the disorder is indistinguishable from SEDC during infancy but a characteristic mottled appearance created by alternating zones of osteosclerosis and osteopaenia develops during early childhood.
12.4.5 Vitreoretinopathy Associated with Phalangeal Epiphyseal Dysplasia
Richards [29] reported a large family with dominantly inherited rhegmatogenous retinal detachment,premature arthropathy and development of phalangeal epiphyseal dysplasia, resulting in brachydactyly. The phenotype appears distinct form other type II collagenopathies,but sequencing identified a novel mutation in the C-propeptide region of COL2A1. The glycine to aspartic acid change occurred in a region that is highly conserved in all fibrillar collagen molecules.
12.4.6 Dominant Rhegmatogenous Retinal Detachment
Rhegmatogenous retinal detachment without systemic involvement can occur as a dominantly inherited trait.Recent work [28,30] has identified a number of novel missense mutations in
COL2A1, some of which have resulted in vitreous phenotypes similar to those seen in isolated cases of rhegmatogenous detachment rather than those seen in Stickler syndrome.Dominant rhegmatogenous retinal detachment (DRRD) is a more appropriate description for this subtype.
12.4.7 Marfan Syndrome
Marfan syndrome is a dominantly inherited disorder of fibrillin production with a prevalence of approximately one in 20,000 and features skeletal, cardiovascular and ocular abnormalities.The fibrillins are high-molecular-weight extracellular glycoproteins,and mutations in the fibrillin gene on chromosome 15 (FBN1) cause Marfan syndrome and dominant ectopia lentis.Fibrillin has been found to be widespread in lens capsule, zonules,iris,ciliary body,choroid and sclera [45]. In a study to correlate genotype with phenotype [35],it was noted that,whereas large-joint hypermobility is more common in those with premature termination codon mutations, lens dislocation and retinal detachment are less common.The association of rhegmatogenous retinal detachment with Marfan syndrome is well recognized and approximately 75% occur below 20years of age [24].Retinal detachment due to giant retinal tear formation is reported to occur in 11% [37]. Although there is a significant association with myopia,this is characteristically developmental in contrast to the congenital,nonprogressive myopia found in type 1 Stickler syndrome. In Marfan syndrome the pupils characteristically dilate poorly because of a structural iris abnormality and, when combined with lens subluxation and thin sclera,retinal detachment repair can be particularly difficult. Pars plana lensectomy and internal tamponade are often required.
12.4.8 Ehlers–Danlos Syndrome
The Ehlers–Danlos syndromes are a heterogeneous group ofinherited connective tissue disorders that are characterized by joint hypermobility and skin fragility and hyperextensibility.Patients
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with the autosomal recessive type VI variant of the Ehlers–Danlos syndromes (EDS VI),also classified as the kyphoscoliotic type, are clinically characterized by neonatal kyphoscoliosis,generalized joint laxity,skin fragility,and severe muscle hypotonia at birth.EDS VI results from mutations in the lysyl hydroxylase 1 gene (PLOD1) causing a deficiency of lysyl hydroxylase.This enzyme hydroxylates specific lysine residues in the collagen molecule to form hydroxylysines, important in collagen cross-linking, which gives collagen its tensile strength.Ocular involvement in EDS VI includes myopia,thin sclera,microcornea and rhegmatogenous retinal detachment. Retinal detachment repair may be complicated by susceptibility to suprachoroidal haemorrhage because ofvascular fragility.
12.4.9 Wagner Vitreoretinopathy
Wagner described 13 affected individuals in a three-generation pedigree with autosomal dominant inheritance, low myopia, fluid vitreous,cortical cataract,and variably affected dark adaptation. The cardinal features noted were the completeabsence ofthe normal vitreal scaffolding and preretinal,equatorial,and avascular greyish-white membranes. Rhegmatogenous retinal detachment was not originally reported. There are no associated systemic features. Twenty-eight members of the original pedigree have been examined [16] and four patients had a history of a rhegmatogenous retinal detachment in one eye at a median age of 20years and 55% of patients older than 45years had peripheral tractional retinal detachments.Chorioretinal atrophy and cataract increased with the patients’age.Several families with Wagner syndrome, including the original pedigree, have been linked to 5q14.3.
12.4.10 X-Linked Retinoschisis
X-linked retinoschisis is an uncommon cause of retinal detachment in childhood accounting for 2.5–5% of all paediatric retinal detachments.
Most affected children have a characteristic foveal schisis and peripheral retinoschisis is seen in 70% (Fig.12.5) [12]. Highly elevated, bullous retinoschisis involving the macula may occur in infancy and eventually reattach spontaneously, leaving pigment demarcation lines [11].Haemorrhage may occur within the schisis cavity or the vitreous.Retinal detachment may occur in up to 16% [12].A full thickness retinal break occurring de novo or a communication between outer and inner leaf defects in the schisis wall may lead to rhegmatogenous retinal detachment.Full thickness breaks may be effectively managed by scleral buckling procedures. Where communication exists between inner and outer leaf breaks, an internal approach may be required. The gene causing X-linked retinoschisis has now been identified and molecular genetic diagnosis in affected males and carrier females is now possible.
12.4.11 Familial Exudative Vitreoretinopathy
Familial exudative vitreoretinopathy (FEVR) is a bilateral, clinically and genetically heterogeneous condition that is characterized by a failure ofperipheral retinal vascularisation.It has a remarkable similarity to retinopathy of prematurity but occurs in full-term infants who are otherwise healthy and have not been treated with oxygen in the neonatal period. The changes may be mild with a peripheral retinal avascular zone, detectable with certainty only by fluorescein angiography, or may slowly progress to cause peripheral neovascularisation and exudative or tractional retinal detachment and vitreous haemorrhage. Rhegmatogenous retinal detachment may also occur.Progression of fundus changes and threat to vision is rare after age 20years. There is a high incidence of myopia, anisometropia and amblyopia, especially in asymmetric disease. Progressive disease may be treated with peripheral photocoagulation or cryotherapy. Vitreoretinal surgery may be challenging because of adherent posterior hyaloid membrane [20].Since the original description in 1969 [7] demonstrating autosomal dominant inheritance, many more reports
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have confirmed autosomal dominant, X-linked and even autosomal recessive forms. The autosomal dominant form (EVR1) can be caused by mutations in the frizzled-4 gene (FZD4) on chromosome 11q13-q23 and also by mutations in the LRP5 (low-density lipoprotein receptor-related protein-5) gene, which maps to 11q13.4. The X-linked form (EVR2) can be caused by mutations of the Norrie disease gene (NDP), which has been mapped to Xp11.4. The gene products are proteins important in Wnt signalling pathways that regulate vascular development in the eye [41,46].The gene underlying EVR3 which has been mapped to 11p12–13 has yet to be identified.Mutations in the LRP5 gene have been suggested to cause autosomal recessive as well as autosomal dominant FEVR [21].
12.4.12 Norrie Disease
Norrie disease is an X-linked recessive syndrome of blindness,deafness,and mental retardation. Affected males are blind at birth or early infancy. About 25% are mentally retarded and about one-third develop progressive sensorineural hearing loss, with onset at any time from infancy to adult life, which may lead to profound deafness.The ocular findings include abnormal vascularization ofthe peripheral retina, bilateral retinal folds, traction retinal de
tachment, vitreous haemorrhage and bilateral retrolental masses.The retinal detachments are usually of early onset and have been diagnosed in utero. Most cases progress to an extensive vitreoretinal mass and bilateral blindness. The gene for Norrie disease has been identified on Xp11.4.Norrin,the product ofthe Norrie disease gene,is a secreted protein important for normal retinal vascularization and regression of hyaloid vessels and also regulates the interaction of the cochlea with its vasculature.
12.4.13 Incontinentia Pigmenti
Incontinentia pigmenti is an X-linked dominantly inherited disorder usually lethal in males, affecting skin, bones, teeth, the central nervous system and eyes. The characteristic skin lesion begins soon after birth,with a linear eruption of bullae, which resolve to leave a linear pattern of hyperpigmentation. Ocular features are usually apparent within the 1styear oflife can occur in up to 77% [18].The main abnormalities are peripheral vascular abnormalities and retinal pigment epithelial defects. Macular vasculopathy with progressive capillary closure has also been described [13]. The affected eye is often microphthalmic and complications can arise from late tractional retinal detachment in up to half of those with eye involvement [18]. Prophylactic cryotherapy or
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Fig.12.5. Characteristic foveal and peripheral features of X-linked retinoschisis
photocoagulation to the peripheral avascular retina has been reported to arrest vascular proliferation and prevent late tractional detachment.Familial incontinentia pigmenti is caused by mutations in the NEMO gene and is referred to as IP2, or classical incontinentia pigmenti. Sporadic incontinentia pigmenti, the so-called IP1, which maps to Xp11, is categorized as hypomelanosis of Ito.
12.5 Retinal Detachment Complicating Developmental Abnormalities
Paediatric rhegmatogenous retinal detachment has been found to be associated with a developmental abnormality in 41% [44].These include retinopathy of prematurity, persistent fetal vasculature (persistent hyperplastic primary vitreous), buphthalmos, coloboma, microspherophakia and retinoblastoma.
12.5.1 Congenital Cataract
Retinal detachment complicating surgery for isolated congenital cataract has been reported to occur in 5% of cases with an average interval of 22years. Detachment may occur during childhood in a minority [10].Whether this is as a result of cataract surgery or related to an intrinsic abnormality is not entirely clear, although a long delay and retinal detachment also occurring in unoperated eyes would suggest the latter.
12.5.2 Ocular Coloboma
Eyes with ocular colobomas are at a significantly increased risk of detachment and account for approximately 0.5% of paediatric retinal detachments [25]. Giant retinal tears are seen in association with lens colobomas [19] and rhegmatogenous detachment may develop in eyes with choroidal coloboma, when small retinal breaks may be found in the hypoplastic retina
overlying the coloboma. Assessment of vision can be difficult and the diagnosis ofdetachment can be further impaired by nystagmus, microphthalmos and cataract. Retinal breaks occurring away from the colobomatous area may be managed by conventional buckling techniques, provided the sclera is of sufficient quality for suturing and the break can be adequately closed. More usually, the retinal break overlies the colobomatous area. Breaks are often small and may be multiple,and their localization can be aided peroperatively by the identification of “schlieren”during internal drainage.Argon laser photocoagulation may be applied around the border ofthe colobomatous area and,where this includes the papillomacular bundle,this may be applied prior to retinal reattachment to minimize associated thermal damage to the nerve fibre layer. Both retinal pigment epithelium and Müller cells are vestigial or absent within the coloboma so that to be effective, retinopexy needs to be applied outside the margin. Recurrent detachment is common [15],so permanent internal tamponade is often required.
12.5.3 Optic Disc Pits and Serous Macular Detachment
The association of serous macular detachment and optic disc pits is well recognized and similar findings with the morning glory disc abnormality indicate that these two conditions are variations ofthe same basic abnormality.Serous macular detachment may occur in 30–50% and usually in patients too young to have a posterior vitreous detachment.Spontaneous resolution is reported to occur in up to 25%,although permanent visual loss may result if macular detachment is prolonged or recurrent.The origin ofthe subretinal fluid is more likely to be cerebrospinal fluid rather than vitreous,although the evidence is not conclusive. The combination of argon laser photocoagulation with internal tamponade either with or without vitrectomy appears to offer greater chance of successful retinal reattachment. Attempts at internal drainage have suggested that there is no rhegmatogenous element and fluid is displaced by gas tamponade until it
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is reabsorbed and recurrence is prevented by formation ofa chorioretinal adhesion at the disc margin.
12.5.4 Retinopathy of Prematurity
The incidence of early retinal detachment following advanced retinopathy of prematurity (ROP) has been substantially reduced by better screening and prophylactic cryotherapy or photocoagulation. However, the visual results following vitreoretinal surgery for those which do progress to retinal detachment have been very disappointing. The major, and often multiple, surgical challenges need to be carefully weighed against a partial and spontaneous retinal reattachment in up to 10% of cases. Lens-sparing techniques have been advocated for pathology confined posterior to the equator [5].Preserving the lens whilst gaining surgical access to the vitreous base in the neonatal eye is technically demanding and requires adequate visualization of the pars plicata by using the operating indirect ophthalmoscope or wide-angle viewing systems. Late retinal detachment following treated or untreated retinopathy of prematurity is wellrecognized and is more commonly rhegmatogenous,but may be tractional or a combination of the two.Retinal changes,which may be an indication of regressed ROP, include myopic changes, displacement of macula and retinal vessels, retinal folds, pigmentary changes, incompletely vascularized peripheral retina, abnormal branching and tortuous and telangiectatic vessels. Repair of late retinal detachment is frequently possible with vitreoretinal surgery and the prognosis relates more to the pre-existing visual potential prior to retinal detachment.A recent report reviewed 29 patients with late rhegmatogenous retinal detachment following regressed,untreated ROP [42].Sixtythree per cent presented between 8 and 20years and 90% were myopic. The majority of breaks were found in the temporal retina, mainly superotemporal. There was a 69% success after initial surgery with scleral buckling or vitrectomy and,with repeated surgery,a final reattachment rate of 97%.
12.6 Other
12.6.1 Inflammatory or Infectious
In one series, 15% of 34 children with rhegmatogenous retinal detachment had a history of inflammatory or infectious disease in the eye with the detachment [44].Acute retinal necrosis, characterized by anterior uveitis, occlusive retinal vasculitis and progressive peripheral retinal necrosis, occurs primarily in nonimmunocompromised adults as a result of reactivated herpes simplex or varicella zoster virus infection.The risk ofretinal detachment is high, reported to be between 25% and 75% and due to retinal breaks,usually following posterior vitreous detachment after the acute phase is over. Although less common,it has been reported to occur in children [6]. Ocular involvement in paediatric AIDS patients has been reported in 50%, 33% having CMV retinitis and 17% retinal detachment [3]. Although uncommon,bilateral serous retinal detachment in Vogt-Koyanagi-Harada may affect young children, and has been reported in children as young as 4years old [8]. Ocular toxocariasis is a rare cause of retinal detachment,usually tractional,associated with a peripheral granuloma.
12.6.2 Exudative Retinal Detachment
Exudative retinal detachment is uncommon but has a wide variety of causes in childhood, including Coat’s disease, retinoblastoma, choroidal haemangioma, capillary haemangioma,posterior scleritis and Harada’s disease. If there is doubt about the diagnosis,computed tomographic (CT) scan or ultrasound,or a careful examination under anaesthesia should be carried out in order to rule out retinoblastoma.
202 Chapter 12 Childhood Retinal Detachment
12.7 Prophylaxis in Rhegmatogenous Retinal Detachment
In contrast to most other paediatric blinding retinal disorders,blindness through retinal detachment is in most cases potentially avoidable if a rationale for the prediction and prevention of retinal detachment could be developed.This goal has been frustrated by a lack of understanding of the factors influencing retinal detachment even in high-risk groups, which are only now beginning to be unravelled. Factors traditionally associated with retinal detachment include refractive error, a positive family history, visible lattice retinopathy and fellow eye involvement,but the nature of these associations is poorly understood. The prevalence of myopia varies enormously and even in Stickler syndrome up to 20% patients may have no significant refractive error. Many patients with retinal detachment have none of the accepted risk features such as lattice retinopathy and,in those that do,retinal tear formation frequently occurs in areas remote from such pathology,so that the associations with accepted risk factors requires refinement. In Stickler syndrome there is a high risk of giant retinal tear (GRT) which is often bilateral and a frequent cause of blindness.The rationale for offering prophylaxis in such high-risk cases is to prevent progression of GRT to detachment by applying treatment to the post-oral retina at the site of giant tear development. A study investigating the role ofprophylactic 360° cryotherapy in type 1 Stickler syndrome has recently been completed. Although there were significant differences between the ages of the control and study groups,the risk of retinal detachment in 204 patients with type 1 Stickler syndrome reduced from 62% to between 3%

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