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Persistent Fetal Vasculature Syndrome


Parag K. Shah, DNB; V. Narendran, DNB; N. Kalpana, DNB.
Correspondance: Department of Pediatric Retina & Ocular Oncology, Aravind Eye Hospital & Postgraduate Institute of Ophthalmology, Avinashi Road, Coimbatore – 641014.Email: drshahpk2002@yahoo.com

 

Definition
It is a congenital ocular disorder where fetal vasculature persists. It can be either subtle (no disturbance in vision) or severe (profound visual loss)

Anatomy
The fetal vasculature is composed of two parts:

  1. Tunica vasculosa lentis: It is situated anteriorly encircling the lens. It has anterior and posterior divisions. Anteri­or division has additional attachments to the pupillary frill of the iris. Posterior division has additional attachments to the cil­iary process and continues with the hyaloid artery posteriorly.
  1. Hyaloid artery: It is situated porteriorly behind the lens. It is also called primary vitreous. The hyaloid vessel extends from posterior surface of lens to the disc. The vasculature fills the vitreous cavity & has many attachments to the retinal surface

Read anatomy of vitreous click here

Normal regression of embryonic vascular system1
During development blood flow to the eye is through hyaloid artery. At the 240-mm stage (seventh month), blood flow in the hyaloid artery ceases. Hyaloid vascular regression occurs in following manner:

The developing lens separates the fetal vasculature from vascular en­dothelial growth factor (VEGF) producing cells, in­ducing apoptosis.

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Pathologies of the Primary Vitreous1
Persistence of the hyaloid vas­cular system occurs in 3% of full-term infants and in 95% of premature infants. There is a spectrum of disorders resulting from persistence of the fetal vasculature.

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Figure 1: Mittendorf’s dot (white arrow).

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Figure 2: Bergmeister's papilla (white arrow).

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Figure 3: Vitreous cyst (white arrow) seen just behind the lens.

Persistent Fetal Vasculature Syndrome (PFVS)3,4

Persistent hyperplastic primary vitreous (PHPV)
As mentioned earlier, it is a congenital ocu­lar disorder in which fetal vasculature does not regress. It is unilateral approximately 90% of the time. No single gene has been identified. The new terminology for Persistent Hyperplastic Primary Vitreous (PHPV) is Persistent Fetal Vasculature Syndrome (PFVS).5 PFVS emphasizes not only the importance of both anterior tunica vasculosa lentis and posterior persistent hyaloid system but also represents the spectrum of structural changes which can present within the eye.

PFVS does not progress during the course of the child's life, but tractional intraocular changes can occur later, most likely due to eye growth. The stalk also can cause traction on the posterior lens capsule leading to posterior lenticonus. Traction on the ciliary body can lead to hypotony. Traction on the retina, lead­s to tractional retinal detachment.

There are three types of PFVS:

  1. Anterior PFVS: It has predominant features of persistent anterior tunica vasculosa lentis without much or any posterior hyaloid component.

Clinical features (Figure 4):

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Figure 4: Anterior PFVS showing microphthalmos with cataract.

Clinical features (Figure 4):

1. Posterior PFVS: It has predominant features of persistent posterior hyaloid artery without much or any anterior tunica vasculosa lentis.

Clinical features:

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Figure 5: Posterior PFVS showing stalk extending from optic disc to lens.

2. Mixed PFVS: Occurs when both the tunica vasculosa lentis and hyaloid system is present. It has a spectrum of presentations depend­ing on the degree of involution of the hyaloid and tunica vasculosa lentis.

Associated diseases
Other systemic associations have been reported with PFV syndrome, most often in association with central nervous system problems 9. However, many of these reports do not rule out mutations in the Norrie disease gene. Associations have also been reported with oculo-palatal-cerebral syn­drome 10, intrauterine herpes simplex virus infection 11, intrauterine exposure to clomiphene, oral-facial-digital syndrome, anterior and posterior colobomas or even cystic globes 12,13 and tuberous sclerosis.14

Differential Diagnosis

  1. Retinoblastoma
  2. Norrie disease: When bilateral PFV syndrome is present8.
  3. Congen­ital cataract.
  4. Walker-Warburg syndrome.
  5. Trisomy.
  6. Familial exudative vitreoretinopathy.
  7. In­continentia pigmenti.
  8. Retinopathy of prematurity.

Visual prognosis
The severity of anterior segment appearance, globe size, severity of lens in­volvement or vascular appearance does notpredict the amount of retinal dysplasia, which in turn often determines the eye's visual result. Retinal dysplasia can be divided into macroscopic and micro­scopic types. Macroscopic dysplasia is defined as changes eas­ily visible with the operating microscope or indirect oph­thalmoscope. Microscopic dysplasia occurs at the cellular or vascular level. Although at present we have no way to deter­mine cell dysplasia, vascular dysplasia can be assessed by flu­orescein angiography. An example of vascular dysplasia is the lack of a capillary-free zone. This finding can be missed with­out angiography and might account for some of the poor vi­sion after successful surgery. Visual evoked potential testing may be useful in predicting retinal dysplasia.7 If a response is present, then it can be helpful in the decision whether to recommend surgery for retinal detachment. This is most helpful when the other eye is uninvolved, and the waveforms can be compared.

Investigations

  1. B scan ultrasound 15: Echography usually shows a shorter than normal globe, although it may be normal in some patients. The lens is often thin and there may be irregularity of the posterior capsule. A retrolental membrane can sometimes be demonstrated. A vitreous band (persistent hyaloid vessel) may be seen extending from the posterior lens capsule to the optic disc. Very often this band is extremely thin and difficult to identify along its entire course (Figure 6). In other situations it can be extremely thick and easy to demonstrate. Sometimes a tractional retinal detachment can be seen posteriorly which can help to differente vitreous band from a closed funnel retinal detachment.

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Figure 6: B scan photo showing a thin band (white arrow) extending aneriorly.

  1. Computed tomographic scanning and magnetic resonance imaging (Figure 7) are rarely needed, mainly to rule out retinoblastoma in doubtful cases.

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Figure 7: MRI scan showing stalk in right eye.

Treatment 3,4

Problem associated with PFVS can be divided into two components that affect vision: the media opacity and retinal changes (both dysplasia and traction). Media opacities are treated similar to that of congenital cataract that is by lens removal, refraction and amblyopia management.

Anterior PFVS

 

Posterior PFVS

Postoperative Treatment     

 

Conclusion

 

References

  1. Sebag J, Nguven N: Embryology of the posterior segment and developmental disorders. B. Vitreous embryology and vitreo-retinal developmental disorders. In: Hartnett ME, editor. Pediatric Retina. Philadelphia. Lippincott Willaims & Wilkins, 2005. pp 13-28.
  2. Meeson A, Palmer M, Calfon M et al. A relationship between apoptosis and flow during programmed capillary regression is revealed by vital analysis. Development 1996;122:3929.
  3. Trese MT, Capone A Jr. Persistent fetal vasculature syndrome (Persistent hyperplastic primary vitreous). In: Hartnett ME, editor. Pediatric Retina. Philadelphia. Lippincott Willaims & Wilkins, 2005. pp 437-443.
  4. Trese MT. Pediatric vitreous surgery. In: Peyman GA, Meffert SA, Conway MD, Chou F. Vitreoretinal surgical techniques. London. Martin Dunitz, 2001. pp 509-518.
  5. Goldberg MF. Persistent fetal vasculature (PFV): an integrated interpretation of signs and symptoms associated with persistent hyperplastic primary vitreous (PHPV). LIV Edward Jackson Memorial Lecture. Am J OphthalmoI 1997;124:587-626.
  6. Shaikh S, Trese MT. Lens-sparing vitrectomy in predominantly posterior persistent fetal vasculature syndrome in eyes with non­axial lens opacification. Retina 2003;23:330-334.
  7. Dass AB, Trese MT. Surgical results of persistent hyperplastic primary vitreous. Ophthalmology 1999; 1 06:280-284.
  8. DeJuan E Jr, Farr A, Noorily S. Retinal detachment in infants. In:Ryan SI, Wilkinson CP, eds. Retina, 3rd ed., vo!. 3, Surgicalretina. St. Louis: Mosby, 2001:2501.
  9. Marshman WE, Jan JE, Lyons CJ. Neurologic abnormalities as­sociated with persistent hyperplastic primary vitreous. Can] Oph­thalmoI 1999;34:17-22.
  10. Pellegrino JE, Engel JM, Chavez D. Oculo-palatal-cerebral syn­drome: a second case (review). Am J Med Genet 2001;99:200-203.
  11. Corey RP, Flynn JT. Maternal intrauterine herpes simplex virusinfection leading to persistent fetal vasculature. Arch Ophthalmol2000;118:837-840.
  12. Tsai PS, O'Brien JM. Retinal hamartoma in oral-facial-digitalsyndrome. Arch Ophthalmol1999; 117:963-965.
  13. Pasquale LR, Romayananda N, Kubacki J, et a!. Congenital cys­tic eye with multiple ocular and intracranial anomalies. Arch Oph­thalmoI 1991;109:985-987.
  14. MilotJ, MichaudJ, Lemieux N, et a!. Persistent hyperplastic pti­mary vitreous with retinal tumor in tuberous sclerosis: report of a case including tumoral immunohistochemistry and cytogenetic analyses. Ophthalmology 1999; 1 06:630-634.
  15. Byrne SF, Green RL. Intraocular tumors. In: Byrne SF, Green RL, editors. Ultrasound of the eye and orbit. Second edition. St. Louis. Mosby, 2002. pp 115-190.