|Year : 2015 | Volume
| Issue : 2 | Page : 169-171
Congenital retinoschisis: A case report
Siddharam Janti, Charanya Chendilnathan, Ayyakutty Muni Raja, Adnan Matheen
Department of Ophthalmology, Chettinad Hospital and Research Institute, Tamil Nadu, India
|Date of Web Publication||13-Jul-2015|
Dr. Siddharam Janti
Chettinad Staff Quarters, Chettinad Hospital and Research Institute, Tamil Nadu
Source of Support: None, Conflict of Interest: None
Congenital retinoschisis is an X linked retinal dystrophy characterized by splitting of neural retina leading to defective vision. A 12-year-old male child came with defective vision since childhood. On examination his best-corrected visual acuity was 6/24 and 6/12 in right and left eye respectively. Indirect ophthalmoscopy showed silver grey retinal reflex and bilateral cartwheel like macular degeneration. Fundus fluorescein angiography was normal. Electroretinogram showed reduction in b-wave amplitude for combined response and normal a-wave and reduced photopic response. Optical coherence topography showed cystic lesions in the inner nuclear and outer plexiform layer of retina. With all the above findings diagnosis of retinoschisis was made out. Hence it is important for early investigation for child with defective vision and start treatment or there will be permanent loss of vision.
Keywords: Electroretinogram, optical coherence topography, retinal dystrophy
|How to cite this article:|
Janti S, Chendilnathan C, Raja AM, Matheen A. Congenital retinoschisis: A case report. Muller J Med Sci Res 2015;6:169-71
| Introduction|| |
Congenital retinoschisis is an X linked retinal dystrophy characterized by splitting of neural retina leading to defective vision. X linked juvenile retinoschisis was first described by Haas in 1898. X-linked retinoschisis (XLRS) is a rare hereditary retinal disease with a prevalence of about 1:120000 to 1:20 000. 
Even though it is rare condition there is no knowledge about this condition with all specialists and the reporting of this disease is less and many cases are missed out. Genetic counseling of ophthalmic diseases are poor in countries like India and we should establish proper genetic counseling centres and there should be knowledge about ophthalmic genetic diseases and treated in early stages to prevent blindness.
| Case Report|| |
A 12-year-old male child came to ophthalmology department with reduced vision in both eyes since childhood, which was gradual in onset and progressive in nature. On examination his Visual acuity was 6/24 and 6/12 in right and left eye respectively. There was no improvement with pinhole or glasses. Intraocular pressure recorded by non-contact tonometer was 17 mmhg in both the eyes. Indirect ophthalmoscopy showed silver grey retinal reflex and bilateral cartwheel like macular degeneration [Figure 1] and [Figure 2]. Fundus fluorescein angiography was normal. Electroretinogram showed reduction in b-wave amplitude for combined response and normal a wave and reduced photopic response [Figure 3]. Optical coherence topography showed cystic lesions in the inner nuclear and outer plexiform layer of retina [Figure 4] and [Figure 5]. With all the above findings, diagnosis of retinoschisis in both eyes was made out.
|Figure 3: Showing electroretinogram changes loss of the b-wave amplitude for the scotopic, nonattenuated flash, as well as loss of the oscillatory potentials|
Click here to view
|Figure 4: Optical coherence topography Showing cystic spaces in both inner and outer macular retina in right eye|
Click here to view
|Figure 5: Optical coherence topography Showing cystic spaces in both inner and outer macular retina in left eye|
Click here to view
| Discussion|| |
Congenital retinoschisis, a relatively rare ocular disorder first described by Haas. It is also been called congenital vascular veils, cystic disease of the retina in children. Juvenile retinoschisis is characterized by bilateral maculopathy, with associated peripheral retinoschisis in 50% of patients. 
X-linked retinoschisis (XLRS) is a rare hereditary retinal disease with a prevalence of about 1:120000 to 1:20 000. It is associated with a mutation in the XLRS1 gene located on the short arm of X chromosome, Xp22.2.  Although considered a rare condition it is one of the most common cause of juvenile macular degeneration.
Cystic-like, stellate maculopathy, or foveal schisis, is present almost universally in XLRS and may be the only abnormality in one half of cases. Similar to the findings in Goldmann-Favre disease, no late leakage occurs on fluorescein angiography. In older patients, foveal schisis evolves into an atrophic maculopathy. The average visual acuity is 20/60 (6/18) at age of 20 years and 20/200 (6/60) at age of 60 years. 
In retinoschisis the inner retina is split at the level of the nerve fiber layer typically in the inferotemporal quadrant, and bilaterally in 40% of patients. The inner layer balloons into the vitreous cavity, and unsupported retinal vessels may lead to recurrent vitreous hemorrhages from associated vitreous traction. Vitreous veils may overlie the retinoschisis.  In XLRS, the vitreous exerts an effect upon the bullous nature of the retinoschisis lesion. The elevation is seen to flatten after a posterior vitreous detachment has produced a separation between the vitreous face and the internal limiting membrane. It is as if the vitreous releases the inner layers of the retina, which allows them to settle back into an anatomical position.
The Mizuo-Nakamura phenomenon has been described in four unrelated men who suffered from X-linked recessive retinoschisis.  Originally described in patients who had autosomal recessive Oguchi's disease, a form of congenital stationary night blindness, this phenomenon also occurs in patients who have an X-linked cone dystrophy. 
The diagnosis is largely based on clinical examination. Optical coherence tomography (OCT) will show widespread cystic spaces in both inner and outer macular retina. Fluorescein angiography generally shows no leakage of dye or true cystoid macular edema in the posterior pole, while the periphery may show slow filling of opacified, dendritic retinal vessels. 
The ERG shows selective loss of the b-wave amplitude for the scotopic, nonattenuated flash, as well as loss of the oscillatory potentials. This ERG abnormality suggests a panretinal dysfunction, in spite of the ophthalmoscopic appearance of only foveal retinal schisis. No consistent ERG findings are found in female carriers, although sporadic reports of abnormalities exist. Visual fields demonstrate absolute scotomas in areas of peripheral schisis, because the neural chain of information is interrupted. A relative central scotoma also is seen. Dark adaptation is normal or only minimally affected in X-linked retinoschisis. There are no known systemic associations. 
Prophylactic treatment of retinoschisis or holes in schisis is not recommended, whereas secondary retinal detachment necessitates intervention. Combined retinal detachment and retinoschisis requires intervention to close the outer layer holes and full-thickness retinal breaks by vitrectomy, perfluorocarbon reattachment, and photocoagulation to areas of schisis and detachment, with scleral buckling of the retinal periphery. Gopal et al. suggests that light burns of laser photocoagulation to the schisis area, in absence of significant traction by the inner layer, is probably safe and may not induce iatrogenic retinal breaks. The mechanism for the successful collapse of schisis cavity is not clear. Obviously, the burns at the outer later of the schisis facilitated the absorption of the intracystic fluid.  In young patients who are unable to comply with rigorous postoperative positioning requirements imposed by instillation of long-acting gas, silicone oil tamponade may be preferable. 
Genetic counseling is necessary in all cases. Carrier state detection generally is regarded as difficult in this disease, although isolated reports exist. Most patients develop a significant loss of macular function in one or both eyes with time. Children need to be examined frequently to rule out amblyopia, vitreous hemorrhage, or retinal detachment.  Hence it is important for early investigation for child with defective vision and start treatment or there will be permanent loss of vision.
| References|| |
Brasil OF, da Cunha AL, de Castro MB, Japiassú RM. Macular hole secondary to X-linked juvenile retinoschisis. Ophthalmic Surg Lasers Imaging 2011;1:42, Online e4-5.
Tantri A, Vrabec TR, Cu-Unjieng A, Frost A, Annesley WH Jr, Donoso LA. X-linked retinoschisis: A clinical and molecular genetic review. Surv Ophthalmol 2004;49:214-30.
Weber BH, Schrewe H, Molday LL, Gehrig A, White KL, Seeliger MW, et al
. Inactivation of the murine X-linked juvenile retinoschisis gene, RS1h, suggests a role of retinoschisin in retinal cell layer organization and synaptic structure. Proc Natl Acad Sci U S A 2002;99:6222-7.
Wang T, Waters CT, Rothman AM, Jakins TJ, Römisch K, Trump D. Intracellular retention of mutant retinoschisin is the pathological mechanism underlying X-linked retinoschisis. Hum Mol Genet 2002;11:3097-105.
Al-Swaina N, Nowilaty SR. Macular hole in juvenile X-linked retinoschisis. Saudi J Ophthalmol 2013;27:283-6.
Sikkink SK, Biswas S, Parry NR, Stanga PE, Trump D. X-linked retinoschisis: An update. J Med Genet 2007;44:225-32.
Yu H, Li T, Luo Y, Yu S, Li S, Lei L, et al
. Long-term outcomes of vitrectomy for progressive X-linked retinoschisis. Am J Ophthalmol 2012;154:394-402.e2.
Dhrami-Gavazi E, Schiff WM, Barile GR. Nanophthalmos and acquired retinoschisis. Am J Ophthalmol 2009;147: 108-10.e1.
Gregori NZ, Berrocal AM, Gregori G, Murray TG, Knighton RW, Flynn HW Jr, et al
. Macular spectral-domain optical coherence tomography in patients with X linked retinoschisis. Br J Ophthalmol 2009;93:373-8.
Gopal L, Shanmugam MP, Battu RR, Shetty NS. Congenital retinoschisis: Successful collapse with photocoagulation. Indian J Ophthalmol 2001;49:265-6.
Shanmugam MP, Nagpal A. Foveal schisis as a cause of retinal detachment secondary to macular hole in juvenile X-linked retinoschisis. Retina 2005;25:373-5.
Yu J, Ni Y, Keane PA, Jiang C, Wang W, Xu G. Foveomacular schisis in juvenile X-linked retinoschisis: An optical coherence tomography study. Am J Ophthalmol 2010;149:973-8.e2.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]