BACKGROUND: In this case report, we present for the first time central retinal artery occlusion (CRAO) and central retinal vein occlusion (CRVO) as a complication of persistent hyaloid artery (PHA).
METHODS: In August 2019, a six-year-old male patient manifested right eye (RE) excessive tearing, conjunctival injection and pain. On examination, RE demonstrated light perception and intraocular pressure of 36 mmHg. The diagnoses of neovascular glaucoma, CRVO and CRAO were established as affirmed with fluorescein angiography (FA). PHA was not reported. Extensive work-up and family history were unremarkable. The child was born on term after uncomplicated twin pregnancy. In December 2019, he was referred to our Centre. Transillumination revealed fully dilated, non-reactive RE pupil, clear lens and tubular remnant of HA containing blood cells in its lumen freely rotating in the anterior vitreous.
CONCLUSIONS: PHA results from failure of apoptosis during gestation. It can easily be observed during the red reflex screening at neonatal wards. We hypothesized that PHA twisting led to torsion of the residual primordial common bulb, branching off to HA and CRA with CRAO occurring first. The consequential CRVO presumably advanced by venous stasis due to decrease in arterial inflow. Liquid vitreous appears as early as 4 years of age enabling PHA to whirl more freely. Thus, in case of PHA, we advocate FA to be performed and if connection with retinal artery is proven, parents should be informed on the possible devastating complications and prompt surgical treatment should be considered.

BACKGROUND: A persistent hyaloid artery is a rare fetal remnant. Several complications such as amblyopia, vitreous hemorrhage, and retinal detachment have been reported. Here, we present a case of vitreous hemorrhage with a persistent hyaloid artery.
METHODS: A healthy 16-year-old male presented with blurred vision in his left eye. Vitreous hemorrhage occurred and absorbed spontaneously. Slit-lamp examination demonstrated a Mittendorf\'s dot and fundus examination revealed a persistent hyaloid artery. Optical coherence tomography (OCT) showed a Bergmeister\'s papilla. The blood flow of the persistent hyaloid artery via the Bergmeister\'s papilla was found by OCT angiography.
CONCLUSIONS: The persistent hyaloid artery should be considered as a cause of spontaneous vitreous hemorrhage of young healthy patient. The OCT angiography will be a useful noninvasive approach to confirm the patency of the persistent hyaloid artery.

The review points to the issues of persistent hyaloid artery, more precisely to possible clinical features, the influence on visual functions and potential complications during intraocular surgeries. In professional journals we can find just few reviews regarding this rare deviation of the eye development, therefore we want to present our experience. The persistent hyaloid artery causes chronical local changes of eye background at both of our patients, retinal detachment and retinoschisis. The findings werent accompanied by significant decrease of visual functions or subjective patients complaints. Considering the potential complications published in journals such as hemoftalmus or retinal vessel occlusion we decided to be more conservative. Thats why we just checked-up the condition of the eye background and we were prepared to perform a surgery if necessary. Key words: persistent hyaloid artery, tractional retinal detachment, retinoschisis.

OBJECTIVE: Walker-Warburg syndrome (WWS) is a type of congenital muscular dystrophy (CMD) characterised by severe brain malformation, lissencephaly, and congenital eye abnormalities. Despite the coexistence of various eye abnormalities, results from optical coherence tomography (OCT) in WWS have not previously been reported. We herein report specific OCT findings in an infant with WWS.
METHODS: The patient was a 14-day-old boy delivered by caesarean section at 38 weeks and 4 days of gestation and with a birth weight of 2,543 g. A cranial MRI showed lissencephaly, hydrocephalus, an encephalocele, and cerebellar hypoplasia, consistent with the diagnosis of WWS.
RESULTS: A bilateral ocular examination showed no abnormalities of the anterior eye segment. A fundus examination showed a persistent hyaloid artery in the vitreous cavity, a widespread loss of fundus pigmentation, transparent choroidal vessels (some choroidal vessel sections were visible), and the absence of a distinct macular reflex. OCT showed no foveal pit and an indistinct laminar structure of the retina. The infant subsequently developed congenital glaucoma and he then died of respiratory failure at the age of 8 months.
CONCLUSIONS: WWS is associated with a high incidence of congenital eye abnormalities, and this infant showed findings consistent with WWS. OCT revealed a marked retinal dysplasia.

METHODS: A 5-year-old male presented with bilateral poor vision, esotropia and a previous diagnosis of cataract since he was 1 year old. The physical examination revealed bilateral posterior paracentric capsule opacification, vitreous cavity with a permeable pulsatile blood filled hyaloid artery in both eyes. He was kept under observation.
CONCLUSIONS: Persistent hyaloid artery is an uncommon faulty primary vitreous regression, often unilateral (although it may be bilateral) and sporadic, associated with microphthalmos. It may be complicated with glaucoma and phthisis bulbi. Vitrectomy plus lensectomy or simple observation are the accepted treatment options.

METHODS: A 72 year-old woman referred for cataract surgery in her right eye. Biomicroscopy revealed a retrocapsular fibrotic tissue in communication with the optic nerve, suggesting a persistent hyaloid artery (PAH). A posterior capsule rupture unexpectedly occurred during lens hydrodissection. One day after surgery, fundus examination showed a combined central retinal artery and vein occlusion.
CONCLUSIONS: PAH is uncommon, but its presence may alert us of this possible complication during cataract surgery.