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Vitreous cysts are rare. Their origin is postulated to be a congenital remnant of the primary hyaloidal system1 or ciliary body pigment epithelium.2 Although most vitreal cysts are asymptomatic, some may cause intermittent visual field defects. Treatment is seldom indicated, though laser photocystotomy or vitrectomy have been suggested.1,3
Iris cysts include iris pigment epithelial cysts and stromal cysts.4 The former may get dislodged into either the anterior chamber or into the vitreous chamber. They become symptomatic when they enlarge and occlude the visual axis. Treatment includes aspiration or surgical excision of the cyst.
Both vitreous and iris cysts have been previously reported as sporadic findings. In this report, we present the clinical and echographic manifestations of intraocular cysts in two siblings.
Two sisters, 11 and 3 years old, were referred for evaluation because of intraocular cysts and amblyopic fellow eyes. They were the products of a full term normal pregnancy with an uneventful perinatal history. Their parents were not relatives. Past medical history was unremarkable. The children in the family were reportedly healthy with no ocular pathology but were inaccessible for examination.
The older sister was known to have worn glasses since the age of 7 years. She complained of intermittent obscuration of vision in her right eye. Her vision was 6/12, J1 right eye and counting fingers at 1 metre with J14 left eye. By indirect ophthalmoscopy of her right eye, a round pigmented, cystic structure was observed in the vitreous cavity (fig 1). The left fundus showed myopic chorioretinal changes with a tilted optic disc. Retinoscopy showed marked myopic anisometropia of +1.00 −1.25×75° right eye and −10.50−2.00×95° left eye. Ultrasonography disclosed a 3.05 mm cystic, round, hypoechogenic vitreal structure (fig 1). It was partially mobile with vitreal after-movements and was tethered to fine vitreal strands. Its walls showed internal reflectivity of 60%, whereas its contents had very low (<5%) reflectivity.
The younger sister was fitted with spectacles at the age of 7 months because of anisometropic myopia. Her visual acuity (picture cube) was 0.03 right eye with unsteady fixation and 0.2 left eye. In her left eye a cystic, pigmented lesion was attached to the posterior iris surface and extended into the anterior vitreous (fig 2). It was located in the superotemporal quadrant causing adjacent lenticular cortical opacities. Indirect ophthalmoscopy revealed bilateral mild retinal myopic changes. High frequency echography of the iris lesion disclosed a cyst with hypoechogenic content measuring 3.68 mm in diameter (fig 2). Cycloplegic refraction showed anisometropic myopia of −7.5−1.00 ×90° right eye and −0.5−3.50 ×80° left eye.
The poor vision in the fellow eye (without cyst) was attributed to the high anisometropia present in both sisters. They were prescribed glasses with anti-amblyopic therapy by patching. No invasive therapy of the cysts in the eye with better vision was recommended.
This reports the unusual association between vitreous and iris cysts found in two siblings. The familial clustering of pigmented intraocular cysts suggests a hereditary aetiology in these sisters. Sallo et al5 reported on the occurrence of primary marginal pigment epithelial iris cysts in four members of one family, thus postulating an autosomal dominant heredity pattern. Nork and Millecchia1 reported an association between vitreous cyst in a patient and corneal dermoid in her son. A familial association between vitreous cyst and iris cyst was not previously reported. Our study, in accordance with previous reports, emphasises the need for examination of family members once an intraocular cyst has been diagnosed in a young child.
The second unusual association described in these siblings is the deeply amblyopic fellow eye with high anisometropic myopic astigmatism. It is not clear whether axial myopia developed because of the amblyopia or whether the amblyopia is secondary to anisometropia. Amblyopia in anisometropia results from the suppression of cortical vision centres that receive inputs from the chronically defocused eye. Also, the eyes of a child with anisometropic amblyopia look normal to the family, leading to delay in detection and treatment.
The physical characteristics of the vitreous cyst we described, including its confinement to the region of Cloquet’s canal, are similar to those reported by others.1 This suggests that the cysts may be remnants of the persistent fetal vasculature, though this manifestation was not included in Goldberg’s description of this disease.6 However, since no surgical excision was performed, we may postulate regarding their cellular origin. Nork and Millecchia1 suggested after histological studies, that the cyst origin was pigment epithelial-type cells. In our study, indirect evidence that the cysts originated from pigment epithelium include their homogeneous brown pigmentation, medium reflectivity, and continuation of iris cyst with the posterior iris surface. The cellular origin of the vitreal cyst is less obvious. It can either be a primary congenital hyaloidal remnant or a cyst that detached from the iris during childhood. Only few have reported on vitreous cysts jarring loose from the ciliary body pigment epithelium.2
Proprietary interest: none.
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