|Year : 2002 | Volume
| Issue : 4 | Page : 330-332
Bietti's crystalline dystrophy
Dinesh K Sahu, Abdul B Rawoof
Department of Ophthalmology, Manipal Hospital, Bangalore-560 017, India
Dinesh K Sahu
Department of Ophthalmology, Manipal Hospital, Bangalore-560 017
This first report from India describes 5 cases of Bietti's crystalline dystrophy without corneal involvement
Keywords: Bietti′s crystalline dystrophy, retinal pigment epithelium, atrophy, India
|How to cite this article:|
Sahu DK, Rawoof AB. Bietti's crystalline dystrophy. Indian J Ophthalmol 2002;50:330-2
Crystalline corneo-retinal dystrophy is an uncommon hereditary condition first reported by Bietti in 1937 as a corneo-retinal degeneration. The disease usually occurs in the second or third decade of life and is characterised by tapetoretinal degeneration with glittering yellow crystals scattered in the retina, atrophy of the retinal pigment epithelium (RPE) and choroid; and sparkling yellow crystals in the superficial paralimbal cornea. The characteristic retinal crystals are observed in all cases but the associated corneal dystrophy is not a consistent feature of the disease. Other reported features include progressive night blindness, constriction of the visual fields, subnormal electroretinogram (ERG) and electro-oculogram (EOG) and defective colour vision in advanced cases.[1-6] Bietti's crystalline retinopathy has been reported from different parts of the world. The majority of patients are of Asian origin, especially of Japanese and Chinese descent.,,, We herein describe 5 Indian patients who showed the features of Bietti's crystalline dystrophy, but without corneal deposits.
| Case report|| |
Between 1998 and 2000, five patients with disease characteristics were identified. They were from two different families from south India. The clinical profiles of these cases are described in [Table - 1]. One of these families is described below.
The first family included two brothers, aged 25 and 31, who were examined in October 1998, for complaints of progressive night blindness and reduction of vision. These brothers were the only sons of consanguineous parents (second-degree consanguinity). The best-corrected visual acuity of the elder brother was 6/18 in right eye and 6/24 in the left eye; and it was 6/18 in both eyes of the younger brother. Both showed mild to moderate constriction of the visual fields with few scattered paracentral scotomas. In both patients, the intraocular pressure (12-21 mm Hg) and anterior segment were normal. Fundus examination showed yellowish-white sparkling crystals scattered all over the posterior pole with a substantial amount of retinal pigment epithelium (RPE) degeneration in both eyes. The crystals appeared at different levels in the retina. The disc and retinal vasculature were unremarkable. The foveal reflex was absent and was replaced by a patch of RPE degeneration with mottled appearance ([Figure - 1]a,[Figure 2]a). Fluorescein angiography showed geographic areas of RPE and choriocapillaries atrophy in the posterior pole with prominence of medium to large choroidal vessels in the early and mid phase. There was diffuse hyperfluorescence in the posterior pole during the late phase corresponding to the areas of RPE degeneration and relatively well preserved chorio-capillaries. The crystals neither transmitted nor blocked the fluorescence ([Figures 1]b, [Figure 2]b). The colour vision showed red-green deficiency on Ishihara's pseudoisochromatic plates. Ocular electrophysiologic tests were done elsewhere. The Arden's ratio in EOG was subnormal, at 1.41-1.75. The normal medical evaluation included baseline haematocrits, urine examination, amino acid analysis of urine and serum, lipid profile, liver function tests, and renal function tests. The parents were not available for examination.
| Discussion|| |
Bietti's crystalline dystrophy is characterised by deposits of sparkling yellowish-white crystals in the retina and sometimes in the peripheral cornea. It usually manifests in the second decade of life as autosomal recessive or dominant disorder. Corneal biopsy specimens have demonstrated crystals resembling cholesterol or cholesterol ester and complex lipid inclusion in the corneal and conjunctival fiboblasts. Similar inclusions are also seen in circulating lymphocytes, suggesting that Bietti's corneoretinal dystrophy may be a systemic abnormality of lipid metabolism., Biochemical studies however do not support cholesterol or cholesterol esters as the stored compound.
Two subtypes of Bietti's crystalline dystrophy have been proposed: a localised type with findings confined to the posterior pole and a diffuse type with widespread retinal findings. Fluorescein angiographic findings depend on the degree of RPE atrophy, pigment mottling, crystal deposition and atrophy of choriocapillaries. Decreased vision nyctalopia and paracentral scotomas are the chief presenting symptoms. The characteristic clinical signs include fine white crystals located in the superficial paralimbal corneal stroma and occasionally in the paralimbal conjunctival epithelium; intraretinal yellow-white crystals located in the posterior pole of retina; and RPE and choriocapillaries atrophy. The retinal vessels and optic nerve are usually normal but there may be some vascular attenuation and/or disc pallor in advanced cases. In addition to a reduction in vision, colour vision defects of the tritan type are not unusual. Visual field defects correspond to areas of RPE and chorio-capillaries atrophy, manifesting as paracentral scotomas or peripheral field loss depending on the severity of the disease.
The ERG is low normal to moderately abnormal in the localised type and severely subnormal to non-recordable in the diffuse type. The EOG is mildly abnormal to non-recordable depending on the severity of the disease.
Ophthalmoscopic and angiographic characteristics are usually sufficient to diagnose Bietti's crystalline dystrophy. Useful adjuncts include colour vision, visual field and electrophysiological testing; corneal biopsy and evaluation of peripheral blood lymphocytes and skin fibroblasts. The differential diagnoses of crystalline retinopathy include oxalosis, cystinosis, canthaxantine use, tamoxifen use, talc emboli, Sjogren Larsson syndrome, idiopathic juxtafoveal retinal telangiectasia and gyrate atrophy. A detailed medical history, thorough systemic and ocular examination; and fluorescein angiography are usually sufficient to exclude these conditions. None of our patients showed any features of these diseases.
In the patients described here the most prominent features included parental consanguinity, progressive diminution of vision, nyctalopia, yellow-white crystals in the posterior pole of retina, and characteristic angiographic features. None of them had corneal deposits. No systemic disease or metabolic disorder was found in any of these patients.
| References|| |
|1.||Bagolini B, Loli Spada G. Bietti's tapetoretinal degeneration with marginal corneal dystrophy. Am J Ophthalmol 1968;65:53-60. |
|2.||Welch RB. Bietti's tapetoretinal degeneration with marginal corneal dystrophy: Crystalline retinopathy. Trans Am Ophthalmol Soc 1977;75:164-79. |
|3.||Wilson DJ, Weleber RG, Klein ML, Welch RB, Green WR. Bietti's crystalline dystrophy: A clinicopathologic correlative study. Arch Ophthalmol 1989;107:213-21. |
|4.||Gizzard WS, Deutman AF, Nijhuis F, Aan De Kerk A. Crystalline retinopathy. Am J Ophthalmol 1978;86:81-88. |
|5.||Harrison RJ, Acheson RR, Dean-Hart JC. Bietti's tapetoretinal degeneration with marginal corneal dystrophy (crystalline retinopathy): Case report. Br J Ophthalmol 1987;71:220-3. |
|6.||Hu DN. Ophthalmic genetics in China. Ophthal Paedic Genet 1983;2:39-45. |
|7.||Hayasaka S, Okuyama S. Crystalline retinopathy. Retina 1984;4:177-81. |
|8.||Richards BV, Brodstein DE, Nussbaum JJ, Ferencz JR, Maeda K, Weiss L. Autosomal dominant crystalline dystrophy. Ophthalmology 1991;98:658-65. |
[Figure - 1]
[Table - 1]
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