Case Report Bilateral Optic Nerve Aplasia: A Rare Isolated Central Nervous System Anomaly Tejaswini P. Khandgave, Varsha N. Kulkarni, Deepa V. Muzumdar, Neelam Puthran
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ABSTRACT Optic nerve (ON) aplasia is a rare developmental anomaly comprising of absence of the ON, ganglion cells and the central retinal vessels. It is usually accompanied by a variety of central nervous system (CNS) malformations. We report an extremely rare case of bilateral true ON aplasia occurring as an isolated CNS anomaly. A 10‑month‑old female child was detected with bilateral absence of fixation, associated with multiple ocular findings of microcornea, anterior embryotoxon, pupillary corectopia, partial aniridia and lens coloboma. The optic disc locations were visible as avascular whitish areas. There were no retinal vessels seen in the disc area or elsewhere. There were bilateral multiple chorioretinal atrophic patches present. B‑scan ultrasonography showed bilateral absence of ONs. Magnetic resonance imaging showed thinned out bilateral ONs with a hypoplastic optic chiasma and optic tract. There were no other CNS anomalies. Flash visually evoked potential was unrecordable.
Website: www.meajo.org DOI: 10.4103/0974-9233.134690 Quick Response Code:
Key words: Aniridia, Anterior Embryotoxon, Coloboma, Corectopia, Microcornea, Optic Nerve Aplasia
INTRODUCTION
O
ptic nerve (ON) aplasia is a rare, congenital developmental anomaly, comprising of absence of ON, central retinal vessels and ganglion cells.1,2 It is generally, accompanied by other central nervous system (CNS) anomalies. A search of the medical literature has revealed only two previous reports of bilateral ON aplasia in otherwise normal children.3,4
CASE REPORT A 10‑month‑old female child, born of a third degree consanguineous marriage, presented with an inability to make eye contact and follow objects since birth. There was no significant history regarding the antenatal, natal and post‑natal period. Developmental milestones had been reached normally. General examination revealed platycephaly of the skull. Neurological and other systemic examinations were within normal limits. On ophthalmic examination, an absence of fixation with up‑rolling of each eye was noted. The child did not
follow any light or visual target and the pupillary reflexes were absent in both eyes. Ocular movements as tested by Doll’s eye maneuver were normal. The ocular adnexa were also normal. Anterior segment examination revealed bilateral anterior embryotoxon with bilateral microcorneas. The right eye had an inferiorly placed pupil (corectopia) while the left eye had partial aniridia associated with a lens coloboma in the inferotemporal quadrant. There were no abnormalities seen on gonioscopy and intraocular pressures were within normal limits. Axial lengths were also within normal limits. Ophthalmoscopy revealed the absence of both optic discs, which were represented by whitish, undefined round structures. Both, the disc area and the retina were devoid of retinal blood vessels. There was marked choroidal tessellation with multiple areas of chorioretinal atrophy seen bilaterally [Figures 1 and 2]. The ONs could not be seen on B‑scan ultrasonography. Magnetic resonance imaging of the brain showed the presence of markedly
Department of Ophthalmology, Bharati Hospital and Research Centre, BVD University Medical College, Pune, Maharashtra, India Corresponding Author: Dr. Tejaswini P. Khandgave, Department of Ophthalmology, Bharati Hospital and Research Centre, BVD University Medical College, Pune ‑ 411 043, Maharashtra, India. E‑mail: [email protected]
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Khandgave, et al.: Bilateral Optic Nerve Aplasia
thinned out ONs [Figure 3]. The optic chiasma and optic tracts were hypoplastic. Flash visually evoked potential (VEP) was unrecordable. There were no other CNS abnormalities detected.
DISCUSSION The ON is formed of the axons of the retinal ganglion cells, which are derived embryologically from the inner neuroblastic layer of the optic cup.5 Failure of development of these cells is rare. When there is accompanying failure of development of mesodermal elements as well, it is termed aplasia of the ON which is an absence of optic disc, ganglion cells and central retinal vessels.1,2 Many cases, which have been reported in literature as ON aplasia are, in fact, cases of ON hypoplasia as some of the features above are present.6 Our case had true bilateral ON aplasia as there were no retinal vessels seen in either eye and the optic discs were visible as ill‑defined avascular whitish structures. The radiological report of thinned ONs, were likely to be merely ON sheaths with some glial tissue. Flash VEP was performed to distinguish ON hypoplasia from ON aplasia. VEP was unrecordable.
Figure 1: Right eye fundus shows whitish area representing disc, absent retinal vessels, multiple chorioretinal atrophic patches. Inset shows a view of inferior retina
Variable ophthalmic features associated with ON aplasia include micro‑ophthalmos, enophthalmos, ptotic lids, squint, microcornea, trabeculodysgenesis, iris hypoplasia, iris coloboma, aniridia and persistent hyperplastic primary vitreous.1,2 In the current case, there were several associated ocular abnormalities, such as microcornea, anterior embryotoxon, corectopia, partial aniridia, lens coloboma and multiple chorioretinal atrophic areas. ON aplasia cases are generally associated with multiple CNS anomalies such as hydrancephaly and hypopituitarism.7,8 Our patient had a platycephaly, which was not accompanied by any CNS abnormalities other than ON aplasia.
Figure 2: Left eye fundus shows whitish area representing disc, absent retinal vessels and a large chorioretinal atrophic patch
Management of such cases is directed towards any associated neurological problems. Since there is no specific ophthalmic management, the parents are counseled regarding education, vocational rehabilitation and mobility training of blind children. To the best of our knowledge, this is only the third case of bilateral ON aplasia in a normal child, which is an extremely rare developmental anomaly.
ACKNOWLEDGMENT Dr. Priscilla Joshi, Prof. and HOD, Department of Radiology, Bharati Hospital and Research Centre, BVD University Medical College, Pune.
Figure 3: T2 weighted magnetic resonance imaging showing thinned out optic nerves with hypoplastic chiasma
Dr. Umesh Kalane, Pediatric Neurologist, Department of Pediatrics, Bharati Hospital and Research Centre, BVD University Medical College, Pune.
Middle East African Journal of Ophthalmology, Volume 21, Number 3, July - September - 2014
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Khandgave, et al.: Bilateral Optic Nerve Aplasia
REFERENCES 1.
2.
3.
4.
5.
Brodsky MC. Anomalies of the optic disc. In: Miller NR, Newman NJ, editors. Walsh and Hoyt̀s Clinical Neuro Ophthalmology. 5th ed., Vol. 1. Baltimore: Williams and Wilkins; 1998. p. 799‑800. Brodsky MC. Congenital optic disc anomalies. In: Taylor D, Hoyt G, editors. Pediatric Ophthalmology and Strabismus. 3rd ed. Baltimore: Elsevier‑Saunders; 2005. p. 637‑8. Scott IU, Warman R, Altman N. Bilateral aplasia of the optic nerves, chiasm, and tracts in an otherwise healthy infant. Am J Ophthalmol 1997;124:409‑10. Sanjari MS, Ghasemi Falavarjani K, Parvaresh MM, Kharazi HH, Kashkooli MB. Bilateral aplasia of the optic nerve, chiasm, and tracts in an otherwise healthy infant. Br J Ophthalmol 2006;90:513‑4.
6. 7. 8.
Nathalie F, Davis EA. Embryology of the eye. In: Yanoff M, Duker JS, editors. Ophthalmology. 2nd ed., Vol. 1. New Delhi: Elsevier; 2006. p. 24. Alqahtani J. Optic nerve aplasia: A case report and literature review. J Pediatr Neurosci 2008;2:150‑3. Storm RL, PeBenito R. Bilateral optic nerve aplasia associated with hydranencephaly. Ann Ophthalmol 1984;16:988‑92. Brodsky MC, Atreides SP, Fowlkes JL, Sundin OH. Optic nerve aplasia in an infant with congenital hypopituitarism and posterior pituitary ectopia. Arch Ophthalmol 2004;122:125‑6.
Cite this article as: Khandgave TP, Kulkarni VN, Muzumdar DV, Puthran N. Bilateral optic nerve aplasia: A rare isolated central nervous system anomaly. Middle East Afr J Ophthalmol 2014;21:262-4. Source of Support: Nil, Conflict of Interest: None declared.
Author Help: Online submission of the manuscripts Articles can be submitted online from http://www.journalonweb.com. For online submission, the articles should be prepared in two files (first page file and article file). Images should be submitted separately. 1) First Page File: Prepare the title page, covering letter, acknowledgement etc. using a word processor program. All information related to your identity should be included here. Use text/rtf/doc/pdf files. Do not zip the files. 2) Article File: The main text of the article, beginning with the Abstract to References (including tables) should be in this file. Do not include any information (such as acknowledgement, your names in page headers etc.) in this file. Use text/rtf/doc/pdf files. Do not zip the files. Limit the file size to 1 MB. Do not incorporate images in the file. If file size is large, graphs can be submitted separately as images, without their being incorporated in the article file. This will reduce the size of the file. 3) Images: Submit good quality color images. Each image should be less than 4096 kb (4 MB) in size. The size of the image can be reduced by decreasing the actual height and width of the images (keep up to about 6 inches and up to about 1800 x 1200 pixels). JPEG is the most suitable file format. The image quality should be good enough to judge the scientific value of the image. For the purpose of printing, always retain a good quality, high resolution image. This high resolution image should be sent to the editorial office at the time of sending a revised article. 4) Legends: Legends for the figures/images should be included at the end of the article file. 264
Middle East African Journal of Ophthalmology, Volume 21, Number 3, July - September - 2014
Copyright of Middle East African Journal of Ophthalmology is the property of Medknow Publications & Media Pvt. Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
Access this article online
ABSTRACT Optic nerve (ON) aplasia is a rare developmental anomaly comprising of absence of the ON, ganglion cells and the central retinal vessels. It is usually accompanied by a variety of central nervous system (CNS) malformations. We report an extremely rare case of bilateral true ON aplasia occurring as an isolated CNS anomaly. A 10‑month‑old female child was detected with bilateral absence of fixation, associated with multiple ocular findings of microcornea, anterior embryotoxon, pupillary corectopia, partial aniridia and lens coloboma. The optic disc locations were visible as avascular whitish areas. There were no retinal vessels seen in the disc area or elsewhere. There were bilateral multiple chorioretinal atrophic patches present. B‑scan ultrasonography showed bilateral absence of ONs. Magnetic resonance imaging showed thinned out bilateral ONs with a hypoplastic optic chiasma and optic tract. There were no other CNS anomalies. Flash visually evoked potential was unrecordable.
Website: www.meajo.org DOI: 10.4103/0974-9233.134690 Quick Response Code:
Key words: Aniridia, Anterior Embryotoxon, Coloboma, Corectopia, Microcornea, Optic Nerve Aplasia
INTRODUCTION
O
ptic nerve (ON) aplasia is a rare, congenital developmental anomaly, comprising of absence of ON, central retinal vessels and ganglion cells.1,2 It is generally, accompanied by other central nervous system (CNS) anomalies. A search of the medical literature has revealed only two previous reports of bilateral ON aplasia in otherwise normal children.3,4
CASE REPORT A 10‑month‑old female child, born of a third degree consanguineous marriage, presented with an inability to make eye contact and follow objects since birth. There was no significant history regarding the antenatal, natal and post‑natal period. Developmental milestones had been reached normally. General examination revealed platycephaly of the skull. Neurological and other systemic examinations were within normal limits. On ophthalmic examination, an absence of fixation with up‑rolling of each eye was noted. The child did not
follow any light or visual target and the pupillary reflexes were absent in both eyes. Ocular movements as tested by Doll’s eye maneuver were normal. The ocular adnexa were also normal. Anterior segment examination revealed bilateral anterior embryotoxon with bilateral microcorneas. The right eye had an inferiorly placed pupil (corectopia) while the left eye had partial aniridia associated with a lens coloboma in the inferotemporal quadrant. There were no abnormalities seen on gonioscopy and intraocular pressures were within normal limits. Axial lengths were also within normal limits. Ophthalmoscopy revealed the absence of both optic discs, which were represented by whitish, undefined round structures. Both, the disc area and the retina were devoid of retinal blood vessels. There was marked choroidal tessellation with multiple areas of chorioretinal atrophy seen bilaterally [Figures 1 and 2]. The ONs could not be seen on B‑scan ultrasonography. Magnetic resonance imaging of the brain showed the presence of markedly
Department of Ophthalmology, Bharati Hospital and Research Centre, BVD University Medical College, Pune, Maharashtra, India Corresponding Author: Dr. Tejaswini P. Khandgave, Department of Ophthalmology, Bharati Hospital and Research Centre, BVD University Medical College, Pune ‑ 411 043, Maharashtra, India. E‑mail: [email protected]
262
Middle East African Journal of Ophthalmology, Volume 21, Number 3, July - September - 2014
Khandgave, et al.: Bilateral Optic Nerve Aplasia
thinned out ONs [Figure 3]. The optic chiasma and optic tracts were hypoplastic. Flash visually evoked potential (VEP) was unrecordable. There were no other CNS abnormalities detected.
DISCUSSION The ON is formed of the axons of the retinal ganglion cells, which are derived embryologically from the inner neuroblastic layer of the optic cup.5 Failure of development of these cells is rare. When there is accompanying failure of development of mesodermal elements as well, it is termed aplasia of the ON which is an absence of optic disc, ganglion cells and central retinal vessels.1,2 Many cases, which have been reported in literature as ON aplasia are, in fact, cases of ON hypoplasia as some of the features above are present.6 Our case had true bilateral ON aplasia as there were no retinal vessels seen in either eye and the optic discs were visible as ill‑defined avascular whitish structures. The radiological report of thinned ONs, were likely to be merely ON sheaths with some glial tissue. Flash VEP was performed to distinguish ON hypoplasia from ON aplasia. VEP was unrecordable.
Figure 1: Right eye fundus shows whitish area representing disc, absent retinal vessels, multiple chorioretinal atrophic patches. Inset shows a view of inferior retina
Variable ophthalmic features associated with ON aplasia include micro‑ophthalmos, enophthalmos, ptotic lids, squint, microcornea, trabeculodysgenesis, iris hypoplasia, iris coloboma, aniridia and persistent hyperplastic primary vitreous.1,2 In the current case, there were several associated ocular abnormalities, such as microcornea, anterior embryotoxon, corectopia, partial aniridia, lens coloboma and multiple chorioretinal atrophic areas. ON aplasia cases are generally associated with multiple CNS anomalies such as hydrancephaly and hypopituitarism.7,8 Our patient had a platycephaly, which was not accompanied by any CNS abnormalities other than ON aplasia.
Figure 2: Left eye fundus shows whitish area representing disc, absent retinal vessels and a large chorioretinal atrophic patch
Management of such cases is directed towards any associated neurological problems. Since there is no specific ophthalmic management, the parents are counseled regarding education, vocational rehabilitation and mobility training of blind children. To the best of our knowledge, this is only the third case of bilateral ON aplasia in a normal child, which is an extremely rare developmental anomaly.
ACKNOWLEDGMENT Dr. Priscilla Joshi, Prof. and HOD, Department of Radiology, Bharati Hospital and Research Centre, BVD University Medical College, Pune.
Figure 3: T2 weighted magnetic resonance imaging showing thinned out optic nerves with hypoplastic chiasma
Dr. Umesh Kalane, Pediatric Neurologist, Department of Pediatrics, Bharati Hospital and Research Centre, BVD University Medical College, Pune.
Middle East African Journal of Ophthalmology, Volume 21, Number 3, July - September - 2014
263
Khandgave, et al.: Bilateral Optic Nerve Aplasia
REFERENCES 1.
2.
3.
4.
5.
Brodsky MC. Anomalies of the optic disc. In: Miller NR, Newman NJ, editors. Walsh and Hoyt̀s Clinical Neuro Ophthalmology. 5th ed., Vol. 1. Baltimore: Williams and Wilkins; 1998. p. 799‑800. Brodsky MC. Congenital optic disc anomalies. In: Taylor D, Hoyt G, editors. Pediatric Ophthalmology and Strabismus. 3rd ed. Baltimore: Elsevier‑Saunders; 2005. p. 637‑8. Scott IU, Warman R, Altman N. Bilateral aplasia of the optic nerves, chiasm, and tracts in an otherwise healthy infant. Am J Ophthalmol 1997;124:409‑10. Sanjari MS, Ghasemi Falavarjani K, Parvaresh MM, Kharazi HH, Kashkooli MB. Bilateral aplasia of the optic nerve, chiasm, and tracts in an otherwise healthy infant. Br J Ophthalmol 2006;90:513‑4.
6. 7. 8.
Nathalie F, Davis EA. Embryology of the eye. In: Yanoff M, Duker JS, editors. Ophthalmology. 2nd ed., Vol. 1. New Delhi: Elsevier; 2006. p. 24. Alqahtani J. Optic nerve aplasia: A case report and literature review. J Pediatr Neurosci 2008;2:150‑3. Storm RL, PeBenito R. Bilateral optic nerve aplasia associated with hydranencephaly. Ann Ophthalmol 1984;16:988‑92. Brodsky MC, Atreides SP, Fowlkes JL, Sundin OH. Optic nerve aplasia in an infant with congenital hypopituitarism and posterior pituitary ectopia. Arch Ophthalmol 2004;122:125‑6.
Cite this article as: Khandgave TP, Kulkarni VN, Muzumdar DV, Puthran N. Bilateral optic nerve aplasia: A rare isolated central nervous system anomaly. Middle East Afr J Ophthalmol 2014;21:262-4. Source of Support: Nil, Conflict of Interest: None declared.
Author Help: Online submission of the manuscripts Articles can be submitted online from http://www.journalonweb.com. For online submission, the articles should be prepared in two files (first page file and article file). Images should be submitted separately. 1) First Page File: Prepare the title page, covering letter, acknowledgement etc. using a word processor program. All information related to your identity should be included here. Use text/rtf/doc/pdf files. Do not zip the files. 2) Article File: The main text of the article, beginning with the Abstract to References (including tables) should be in this file. Do not include any information (such as acknowledgement, your names in page headers etc.) in this file. Use text/rtf/doc/pdf files. Do not zip the files. Limit the file size to 1 MB. Do not incorporate images in the file. If file size is large, graphs can be submitted separately as images, without their being incorporated in the article file. This will reduce the size of the file. 3) Images: Submit good quality color images. Each image should be less than 4096 kb (4 MB) in size. The size of the image can be reduced by decreasing the actual height and width of the images (keep up to about 6 inches and up to about 1800 x 1200 pixels). JPEG is the most suitable file format. The image quality should be good enough to judge the scientific value of the image. For the purpose of printing, always retain a good quality, high resolution image. This high resolution image should be sent to the editorial office at the time of sending a revised article. 4) Legends: Legends for the figures/images should be included at the end of the article file. 264
Middle East African Journal of Ophthalmology, Volume 21, Number 3, July - September - 2014
Copyright of Middle East African Journal of Ophthalmology is the property of Medknow Publications & Media Pvt. Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
