Unusual retinal vessels

http://www.optometry.co.uk/articles/docs/8a09ee2c4a719fd88e90e28ce345ac0e_Swann1991119.pdf

Remnants of the hyaloid system

• Mittendorf dot
  Bergmeister’s papilla
  Vogt’s arcuate line
• very rarely, the whole vessel being preserved from disc to lens
• associated with persistence of the primary vitreous, coloboma and ONH hypoplasia

Cilioretinal artery

• present in 30-40% of eyes
• arise from the temporal optic disc in a hook-like manner, often traversing the papillomacular area
  more common in cases of optic disc pit, situs inversus, pre-papillary loops and optic disc drusen
• in CRAO, the presence of a cilioretinal arteriole may enable some degree of central vision to be retained
  

Congenital tortuosity

• more commonly involves retinal arterioles than veins
• usually non-progressive with all other findings being normal
• there is a progressive form which is inherited as an autosomal dominant trait and may be
  associated with retinal haemorrhages
  should bedifferentiated from that secondary to other problems, such as epiretinal membrane,
  vein occlusion and diabetes

Situs invertus

• retinal vessels emerge from the optic disc in an anomalous direction
• typically seen in tilted disc syndrome and also in myopic eyes
• a dragged disc and vessels can have a similar appearance and occurs in retinopathy of prematurity

Congenital retinal macrovessel

• a retinal vessel, usually the inferio-temporal retinal vein, is enlarged and drains an area
  superior to the macula
• vision may be slightly reduced by the large vessel crossing the macula
• macular cysts are more common in these patients

Pre-papillary loops

• 95% of these vessels are arterioles, and usually originate from and return to an arteriole on or near the disc
  the loops may be small and simple or large and corkscrewed
• many are surrounded by the white remnants of Bergmeister’s papilla
  usually unilateral with associated cilioretinal arterioles
• fill before or with other retinal arteries on fluorescein angiography and do not leak
• vitreous haemorrhage and occlusion of the loop have been reported

AV malformations

• arterioles and veins communicate without an intervening capillary bed
• may be isolated to a small arteriole and venule or be widespread involving the entire vascular tree
  intracranial and facial vascular malformations may be associated and constitute the Wyburn-Mason syndrome
  similar vascular anomalies can involve the orbit, conjunctiva, sclera and iris, and
  neovascular glaucoma can be a complication
• should be differentiated from the phakomatosis von Hippel-Lindau’s disease
• patients should be referred for neurological assessment

Collateral vessels

• preformed capillaries connecting retinal, and retino-choroidal circulations
• indicate a preceding vascular disorder which may point to a significant ocular and/or systemic disease
  unlike new vessels, they do not leak on fluorescein angiography
• potential causes include retinal vein thrombosis and glaucoma
• if the patient, especially a middle-aged female, has a chronic, progressive vision loss, together with a pale, swollen optic disc and a disc collateral, then optic nerve sheath meningioma is a likely cause

New vessels

• new vessels proliferate following ischaemia in conditions such as diabetic retinopathy and central retinal vein thrombosis
• may form on the optic disc, elsewhere in the fundus and in the anterior segment
• delicate feathery appearance and leak fluorescein