Congenital Nystagmus

Congenital Nystagmus; Horizontal Pendular Nystagmus; Optokinetic Nystagmus Absent; Infantile Nystagmus SyndromeOscillations of the EyesThis young boy has oculocutaneous albinism. In 1979 he presented for evaluation of oscillations of his eyes present since birth. He had no head turn or head tremor. Diagnosis: Albinism Congenital sensory nystagmus Ocular Albinism: Infants with albinism of all types are typically slow to see, often appearing blind in the early postnatal weeks. In the early weeks, before the nystagmus and ocular motor instabilities typical of albinos are manifest, wandering eye movements may be seen. Diaphanous irides and foveal hypoplasia are other features of an albino's eyes. Slit-lamp examination may be needed to identify microscopic sites in the irides that transilluminate light. Visual acuity: Albino infants develop good grating acuity, although letter acuity is destined to be impaired to variable degrees, often in the range of 20/60 to 20/80. Misrouting of the visual pathways: Misrouting of the visual pathways such as excessive crossing at the chiasm or absent crossing of the nasal fibers in achiasmatic subjects with congenital see-saw nystagmus, have lead to development of models for congenital nystagmus based on missed wiring of visual or proprioceptive pathways. The misrouting of the visual pathways characteristic of the hypopigmentation syndromes can be documented by using VEP techniques. The relationship between this misrouting of the visual pathways and congenital nystagmus is yet to be determined. However, it has been suggested that the pendular form of congenital nystagmus may arise from oscillations within the pursuit system. (See Table 10-7 Visual System Disorders Associated with Infantile Nystagmus Syndrome (Chp 10, p513 (ref 10)). Box 10-11 Clinical features of Infantile Nystagmus Syndrome (ref 10) Genetics: Mutations of the tyrosinase gene or P-gene have been identified in some patients with oculocutaneous albinism.This little boy with Infantile Nystagmus Syndrome in association with oculocutaneous albinism has: • Conjugate pendular nystagmus in primary gaze • No head turn • No latent nystagmusCongenitalSurgical procedures for congenital nystagmus are discussed in ref 101. Abel, L.A., Wang, Z.I. and Dell'Osso, L.F.: Wavelet Analysis in Infantile Nystagmus Syndrome: Limitations and Abilities. Invest. Ophthalmol. Vis. Sci. 2008. (In Press). http://www.ncbi.nlm.nih.gov/pubmed/18450585 2. Apkarian P, Bour LJ, Barth PG, Wennigerprick L, Verbeeten B. Non-decussating retinal-fugal fibre syndrome - An inborn achiasmatic malformation associated with visuotopic misrouting, visual evoked potential ipsilateral asymmetry and nystagmus. Brain 1995;118:1195-1216. http://www.ncbi.nlm.nih.gov/pubmed/7496780 3. Classification of Eye Movement Abnormalities and Strabismus (CEMAS) Working Group. http://www.nei.nih.gove/news/statements/cemas 2003. 4. Collewijn H, Apkarian P, Spekreijse H. The oculomotor behavior of human albinos. Brain 1985;108:1-28. http://www.ncbi.nlm.nih.gov/pubmed/3978393 5. Creel D, O'Donnell FE Jr. Witkop CJ. Visual system anomalies in human ocular albinos. Science 1978;201:931-933. http://www.ncbi.nlm.nih.gov/pubmed/684419 6. Creel D, Spekreijse H, Reits D. Visual evoked potential (VEP) methods of detecting misrouted optic projections. Doc Ophthalmol Proc Serv 1981;27:157. 7. Giebel LB, Strunk KM, King RA et al. A frequent tyrosinase gene mutation in classic, tyrosinase-negative (type 1A) oculocutaneous albinism. Proc Natl Acad Sci USA 1990;87:3255. http://www.ncbi.nlm.nih.gov/pubmed/1970634 8. Hertle RW, Maldanado VK, Maybodi M, Yang D. Clinical and ocular motor analysis of the infantile nystagmus syndrome in the first 6 months of life. Br J Ophthalmol 2002;86:670-675. http://www.ncbi.nlm.nih.gov/pubmed/12034691 9. Jacobs JB, Dell'Osso LF. Congenital nystagmus: hypothesis for its genesis and complex waveforms within a behavioral ocular motor system model. J Vis 2004;4:604-625. http://www.ncbi.nlm.nih.gov/pubmed/15330705 10. Leigh JR, Zee DS. Diagnosis of Nystagmus and Saccadic Instrusions. Chp 10; 475-558. In: The Neurology of Eye Movements, Fourth Edition. Oxford University Press, NY 2006; 11. McCarty JW, Demer JL, Hovis LA, Nuwer MR. Ocular motility anomalies in developmental misdirection of the optic chiasm. Am J Ophthalmol 1992;113:86-95. http://www.ncbi.nlm.nih.gov/pubmed/1728153 12. Naumann GOH, Lerche W, Schroeder W. Foveola-Aplasie bei Tyrosinase-positivem oculocutanen Albinismus. Albrecht Von Graefes Arch Klin Exp Ophthalmol 1976;200:39. http://www.ncbi.nlm.nih.gov/pubmed/822741MTcongenitalvsacquirednystagmus; mtcongenitalmotornystagmu