Ординатура / Офтальмология / Английские материалы / Electrophysiology of Vision_Lam_2005

of the optic disc, vitreous hemorrhage, tractional retinal detachment, cystoid macular edema, and neovascular glaucoma may also occur. The disease is linked to chromosome 11q13 (24).

Affected patients are asymptomatic in early adulthood but have vitreous cells and a selective reduced ERG b-wave response that is most apparent under dark-adapted condition (23). With progression of the disease, the ERG is further impaired and may become non-detectable. The EOG and VEP findings have not been extensively studied but are likely to parallel reduction in ERG responses.

REFERENCES

1.Ahmad NN, Ala-Kokko L, Knowlton RG, Jimenez SA, Weaver EJ, Maguire JI, Tasman W, Prockop DJ. Stop codon in the procollagen II gene (COL2A1) in a family with the Stickler syndrome (arthro-ophthalmopathy). Proc Natl Acad Sci USA 1991; 88:6624–6627.

2.Stickler GB, Belau PG, Farrell FJ. Hereditary progressive arthro-ophthalmopathy. Mayo Clin Proc 1965; 40:433–455.

3.Richards AJ, Baguley DM, Yates JR, Lane C, Nicol M, Harper PS, Scott JD, Snead MP. Variation in the vitreous phenotype of Stickler syndrome can be caused by different amino acid substitutions in the X-position of the type II collagen Gly-X-Y triple helix. Am J Hum Genet 2000; 67:1083–1094.

4.Wagner H. Ein bisher unbekanntes Erbleiden des Auges (Degeneratio hyaloideoretinalis hereditaria). Beobachter im Ka¨nton Zu¨ rich. Klin Monatsbl Augenheilkd 1938; 100: 840–857.

5.Gupta SK, Leonard BC, Damji KF, Bulman DE. A frame shift mutation in tissue-specific alternatively spliced exon of Collagen 2A1 in Wagner’s vitreoretinal degeneration. Am J Ophthalmol 2002; 133:203–210.

6.Brown DM, Graemiger RA, Hergersberg M, Schinzel A, Messmer EP, Niemeyer G, Schneeberger SA, Streb LM, Kimura AE, Weingeist TA, Sheffield VC, Stone EM. Genetic

linkage of Wagner disease and erosive vitreoretinopathy to chromosome 5 q13–14. Arch Ophthalmol 1995; 113:671–675.

7.Perveen R, Hart-Holden N, Dixon MJ, Wiszniewski W, Fryer AE, Brunner HG, Pinkners AJ, van Beersum SE, Black GC. Refined genetic and physical localization of the Wagner disease (WGN1) locus and the genes CRTL1 and CSPG2 to a 2- to 2.5-cM region of chromosome 5q14.3. Genomics 1999; 57:219–226.

8.Hirose T, Lee KY, Schepens CL. Wagner’s hereditary vitreoretinal degeneration and retinal detachment. Arch Ophthalmol 1973; 89:176–185.

9.Criswick VG, Schepens CL. Familial exudative vitreoretinopathy. Am J Ophthalmol 1969; 68:578–594.

10.Plager DA, Orgel IK, Ellis FD, Hartzer M, Trese MT, Shastry BS. X-linked recessive familial exudative vitreoretinopathy. Am J Ophthalmol 1992; 114:145–148.

11.Muller B, Orth U, Van Noubuys CE, Duvigneau C, Fuhrmann C, Scheinger E, Laqua H, Gal A. Mapping of the autosomal dominant exudative vitreoretinopathy locus (EVR1) by multipoint linkage analysis in four families. Genomics 1994; 20:317–319.

12.Feldman EL, Norris JL, Cleasby GW. Autosomal dominant exudative vitreoretinopathy. Arch Ophthalmol 1983; 101: 1532–1535.

13.Ohkubo H, Tamino T. Electrophysiological findings in familial exudative vitreoretinopathy. Doc Ophthalmol 1987; 65: 461–469.

14.Van Noubuys CE. Dominant exudative vitreoretinopathy and other vascular developmental disorders of the peripheral retina. Doc Ophthalmol 1982; 54:1–414.

15.Blair NP, Goldberg MR, Fishman GA, Salzano T. Autosomal dominant vitreoretinochoroidopathy. Br J Ophthalmol 1984; 68:2–9.

16.Kaufman SJ, Goldberg MR, Orth DH, Fishman GA, Tessler HH, Mizuno K. Autosomal dominant vitreoretinochoroidopathy. Arch Ophthalmol 1982; 100:272–278.

17.Roider J, Frisch E, Hoerauf H, Heide W, Laqua H. Autosomal dominant vitreoretinochoroidopathy. Retina 1997; 17:294–299.

18.Traboulsi EI, Payne JW. Autosomal dominant vitreoretinochoroidopathy: report of the third family. Arch Ophthalmol 1993; 111:194–196.

19.Goldberg MR, Lee FL, Tso MO, Fishman GA. Histopathologic study of autosomal dominant vitreoretinochoroidopathy: peripheral annular pigmentary dystrophy of the retina. Ophthalmology 1989; 96:1736–1746.

20.Han DP, Burke JM, Blair JR, Simons KB. Histopathologic study of autosomal dominant vitreoretinochoroidopathy in a 26-year-old woman. Arch Ophthalmol 1995; 113:1561–1566.

21.Han DP, Lewandowski MF. Electro-oculography in autosomal dominant vitreoretinochoroidopathy. Arch Ophthalmol 1992; 110:1563–1567.

22.Kellner U, Jandeck C, Kraus H, Foerster MH. Autosomal dominant vitreoretinochoroidopathy with normal electrooculogram in a German family. Graefes Arch Clin Exp Ophthalmol 1998; 236:109–114.

23.Bennett SR, Folk JC, Kimura AE, Russell SR, Stone EM, Raphtis EM. Autosomal dominant neovascular inflammatory vitreoretinopathy. Ophthalmology 1990; 97:1135–1136.

24.Stone EM, Kimura AE, Folk JC, Bennett SR, Nichols BE, Streb LM, Sheffield VC. Genetic linkage of autosomal dominant neovascular inflammatory vitreoretinopathy to chromosome 11q13. Hum Mol Genet 1992; 1:685–689.

Birdshot retinochoroidopathy (vitiligenous chorioretinitis)

Diffuse unilateral subacute neuroretinitis (DUSN)

Zonal inflammatory retinal disorders:

Acute zonal occult outer retinopathy (AZOOR)

Multiple evanescent white-dot syndrome (MEWDS)

Acute macular neuroretinopathy (AMN)

Multifocal choroiditis

Punctate inner choroidopathy (PIC)

Paraneoplastic and immune-related retinopathies:

Cancer-associated retinopathy (CAR)

Recoverin-associated retinopathy and autoimmune retinopathy without cancer

Melanoma-associated retinopathy (MAR)

CRMP-5 paraneoplastic retinopathy and optic neuropathy

INFLAMMATORY RETINAL DISORDERS

Uveitis (Non-Specific Intraocular Inflammation)

In acute iridocyclitis, or anterior uveitis, the ERG is normal because the retina is not involved (1).

In patients with pars planitis or intermediate uveitis, Cantrill et al. (2) found selective prolonged scotopic and photopic b-wave responses and reduced oscillatory potentials in a study of 13 patients. In contrast, Tetsuka and colleagues

(3) performed ERG in nine patients with pars planitis and noted that the a-wave and b-wave were equally impaired without a selective effect on the b-wave. In the same study, the ERG responses varied from supernormal, due to early active retinal inflammation, to non-detectable from late chronic severe diffuse retinal degeneration. The EOG lightpeak to dark-trough ratios were also reduced.

In posterior uveitis, the ERG is normal with vitreous inflammation and minimal retinal involvement (1). However, when retinal vasculitis is present, impaired ERG responses

correlate directly with the degree of vasculitis on fluorescein angiography (4). When intraocular inflammation produces cystoid macular edema, the foveal focal ERG and multifocal ERG are impaired due to localized retinal dysfunction but the full-field ERG is normal or only mildly impaired since the foveal region may contribute only about 10% of the fullfield cone ERG response. Because the ERG impairment in cystoid macular edema is non-specific, fluorescein angiography and optical coherence tomography are more useful in determining any active macular inflammation. Reduced EOG light-peak to dark-trough ratios parallel ERG reductions, but the EOG ratio may be mildly supernormal in early uveitis presumably due to the acute inflammatory response

(4). The VEP findings parallel ERG responses but may be further reduced when secondary optic nerve head inflammation occurs as part of the posterior uveitis.

Presumed Ocular Histoplasmosis Syndrome

(POHS) and Toxoplasmosis Retinopathy

Focal lesions of the choroid and retina from presumed histoplasmosis and toxoplasmosis cause local areas of retinal dysfunction that rarely produce significant reduction on full-field ERG unless the lesions are extensive. However, areas of localized retinal dysfunction may be detected with multifocal ERG technique.

Behc¸et Disease

Behc¸et disease, described in 1937, is a generalized vasculitis syndrome of unknown origin characterized by intraocular inflammation and ulcers of the mouth and genitals. Other manifestations of the vasculitis include retinal vasculitis, ischemic optic neuropathy, cerebrovascular occlusion, gastrointestinal bleed, and arthralgia. Behc¸et disease is rare in most countries, but is much more common in the Middle and Far East. Factor V Leiden mutation is found at an increased frequency in Behc¸et patients with retinal vascular occlusions (5).

The diagnosis of Behc¸et disease is made on clinical findings. The ERG is variable in Behc¸et disease and correlates with the severity of retinal involvement. Cruz et al. (6) performed full-field ERG and pattern VEP on 12 patients with posterior uveitis from Behc¸et disease. Marked reduction of ERG oscillatory potentials was noted early in the disease with subsequent impairment of a-wave and b-wave. Significant prolongation of the VEP response was also found when the ERG responses were impaired. These impaired ERG responses from Behc¸et disease were confirmed by other authors, some of whom found a selective reduction of the ERG b-wave presumably due to retinal ischemia (7–9). However, in a comparison of 16 Behc¸et patients and 11 patients with non-specific posterior uveitis by Hatt and Niemeyer (10), the scotopic full-field ERG responses were found to be more impaired than photopic responses in both groups, and no characteristic ERG changes for Behc¸et disease were encountered. Therefore, in Behc¸et disease ERG is helpful to assess retinal function although the ERG findings are variable and non-specific. The EOG and VEP in Behc¸et disease have not been extensively studied but are likely to parallel ERG responses.

Vogt–Koyanagi–Harada Disease

Vogt–Koyanagi–Harada disease is a granulomatous inflammatory disorder due to autoimmune response associated with melanocytes (11). The disease is more common in more pigmented ethnic groups. Ocular manifestations include bilateral diffuse choroiditis, serous retinal detachment, pigmentary retinopathy, vitritis, and optic disc hyperemia. Systemic findings include meningismus, alopecia, poliosis, and vitiligo.

Reports of electrophysiological findings in Vogt– Koyanagi–Harada disease are scarce. Degree of ERG impairment correlates with retinal involvement.

Sympathetic Ophthalmia

Sympathetic ophthalmia is a rare form of uveitis in which intraocular inflammation occurs in both eyes after penetrating

trauma or ocular surgery in one eye (12). Aside from penetrating ocular trauma, sympathetic ophthalmia may follow intraocular procedures such as paracentesis, iridectomy, lysis of iris adhesions, cyclodialysis, cataract extraction, evisceration, retinal detachment repair, and pars plana vitrectomy. In addition, sympathetic ophthalmia may rarely follow nonpenetrating ocular procedures such as cyclocryotherapy, laser cyclotherapy, proton beam irradiation, and helium ion therapy for choroidal melanoma. The fellow eye to the injured or operated eye is referred to as the sympathizing eye. The onset of blurred vision and photophobia typically occurs between 3 weeks and 6 months following the inciting trauma or surgery. Clinical features include iridocyclitis and diffuse, focal, or multifocal granulomatous choroiditis. The etiology of sympathetic ophthalmia is unknown but an autoimmune response to ocular antigens is suspected. The risk of sympathetic ophthalmia is reduced if the injured, exciting eye is promptly enucleated after the trauma.

The diagnosis of sympathetic ophthalmia is made based on history and clinical features. Reports of electrophysiological findings in sympathetic ophthalmia are scarce. Degree of ERG impairment correlates with retinal involvement.

Acute Posterior Multifocal Placoid

Pigment Epitheliopathy

Acute posterior multifocal placoid pigment epitheliopathy commonly called ‘‘APMPPE’’ is characterized by multiple flat gray-white subretinal lesions involving the retinal pigment epithelium. The disease is typically bilateral and the cause is unknown. Affected persons are often young adults who develop blurred vision over days and may have had a recent flu-like illness. In early APMPPE, fluorescein angiography shows early blockage by lesions that become diffusely stained in midand late-phases. The lesions fade over several days, and visual recovery occurs over weeks to months. Visual prognosis is good with final visual acuities of 20=30 or better in most patients. Recurrences are infrequent. Occasionally, APMPPE patients may have concomitant central nervous

system vasculitis. The diagnosis of APMPPE is based on clinical features and fluorescein angiographic findings.

During the acute phase of APMPPE, the ERG and EOG are variably impaired and are related to the degree of ocular involvement. Fishman et al. (13) documented a patient who initially had reduced EOG and full-field ERG, and with recovery, the ERG normalized but the EOG remained impaired, suggesting persistent dysfunction of the retinal pigment epithelium. However, Smith et al. (14) reported a patient who initially had minimally reduced full-field ERG and a notably reduced EOG amplitude ratio of 1.55 which normalized three weeks later. More recently, Vianna et al. (15) reviewed the records of 42 APMPPE patients. The EOG was performed on 36 affected eyes, and 21 (58%) eyes had reduced light-peak to dark-trough amplitude ratios of less than 1.8. In the same series, full-field ERG was available in 30 eyes, and reduced ERGs were found in only three (10%) patients. Taken together, although both variable ERG and EOG impairments may occur during the acute phase of APMPPE, the EOG is more likely to be abnormal. Both ERG and EOG improve with disease recovery, but EOG impairments are more likely to persist. Reports of VEP in AMPPE are rare; the VEP is likely to parallel ERG findings and macular function.

Serpiginous Choroiditis

Serpiginous choroiditis is a rare, acute, and chronically recurrent disorder characterized by demarcated geographic zones of gray-white discoloration of the retinal pigment epithelium, followed by atrophy of the retinal pigment epithelium and choroid. Other names for the same disorder include geographic choroiditis and helicoid peripapillary choroidopathy. The cause is unknown and young or middle-aged adults are typically affected. Acute onset of central scotoma in one eye is common, and sequential involvement of the contralateral eye is common. The lesions usually occur initially in the peripapillary region and tend to spread over months to years to involve the macula and the peripheral retina. The diagnosis is made on clinical features.