ROP Flashcards
Vascularization of the Retina
Fetus is Hypoxic ar 25-35 mm/Hg
VEGF: Vascular Endothelial Growth Factor
You will not grow blood vessesl unless you have this
IGF-1: Insulin-like growth factor 1
need IGF-1 for VEGF to work; it gives it “permission”
IN THE FETUS: VEGF production is regulated by oxygen
VEGF increases by hypoxia and decreases with hyperoxia
2nd stages-once we have ROOP, it is better to sat better
O2 controls VEGF
Vascularization of the retina
Fetus: Igf-1 activates VEGF
IGF-1
levels increase in the 3rd trimester (immature miss them); large amounts in the amniotic fluid; protein intake increases the levels in preterms; s start proteinearly; ROP linked to poorly nourished infants with protein deficits and worsens ROP
1st Phase: Development of ROP
After Birth: retinal development shuts down; room air after birth and more O2 than used to in utero and retinal development shuts down
Avascular area becomes quiet and shrinks down and stops because VEGF is decreased because of Increase in O2
lose placenta; lose noursihment
2nd Phase: Development of ROP
After ~ 4 weeks, the avascular retina increases its metabolic needs and VEGF is again produced
VEGF accumulates until:
ILGF-1 levels reach threshold level reactivating VEGF’s process of retinal vascularization
If IGF-1 reached threhold early and VEGF amounts are not excessive, then no ROP
If IGF-1 levels reach threshold late, then VEGF levels will be excessive and ROP will occur
excessive VEGF causes out of control angiogenesis
causes balled-up vessels, AV hunts at the body of avascular and vascular parts of the retina and you get a little line, then a ridge, then a BIG ridge with little vessels and fibroblasts hooking into the white part of the eye causing traction with causes detatchment
Development of ROP
If ROP develops, it usually occurs between weeks 34-40 weeks after conception
WHO gets ROP?
Premature, severity of illness, number of complications
Zone 1
central visionis preserved if you have zone one/no ROP in zone 1
causes 80% loss of central vision; thankfully most babies who get ROP are already in zone 2
Zones
3 zones moving outward from optic disc
Stages 1-5
Clock hours 0-12hrs
International classification of ROP:
ROP seen is Zone 1 has the worst prognosis
ROP seen initially in Zone III is mild and recovers fully
Stages of ROP
Based on the overproduction of vessels at border of vascularized and avascularized retina
Stage 1
Distinct line between vascular and avascular retina
Stage 2 ROP
Line has become a ridge (vessels cant cross ridge)
Stage 2 with PLUS disease
Plus disease determined by the findings in zone near optic disc
Plus Disease
As ROP in periphery becomes more severe, the veins become dilated and arteries become tortous
RUSH dusease
ROP in Zone 1 accompanied by severe plus disease: can pregress very rapidly to total retinal detatchment
Stage 3 ROP
Vessels now extended BEYOND retina into vitreous
Stage 4
Partial retinal detatchment (4a-spares macula; 4b-macula is involved
Stage 5
TOTAL RETINAL DETATCHMENT
Criteria for intervention
Wait and watch: Zone 1: stage 1 or stage 2 WITHOUT PLUS DISEASE
ZONE II stage 1,2,3 without Plus disease
Threshold ROP
untreated threshold ROP progresses to retinal detatchment in 50% of the cases
Most infants with ROP undergo regression
Even infants with severe stage 3 ROP can be expected to have good vision if regression occurs without distortio or detachment of the retina
Complications of ROP
a late-onset form of glaucoma described in ROP pts when they reach 12-45 yrs
All infants meeting ROP criteria need rexamined
6 months, 3 years and then at least yearly
Treatment of ROP: Purpose:
Eliminates abnormal BV before they lay down enough scar tissue to produce retinal detatchemtn; desctrction of the remaining avascular retina causes production of VEGF to cease
Cryotherapy
Cold ice probe; rarely used
Laser therapy
condensation of protein material by controlled use of light rays; conventional laser thx resulted in permanent destruction of vessels in the peripheral retina
Intravitreal tr allows for continued vesssel growth into the peripheral retina
inject into vitreous to decrease angiogenic factor, VEGF by rendering it inactive
bevacizumab is effective more rapidly than laser
laser: 7-14 days for exsisting VEGF in the vitreous to diminish (ROP to stop getting worse)
Injection imediately stops the effects of VEFG in the perpheral retina andin the vitreous
laser vs Bevacizumab:
no need for intubation and ventilation, less need for post op opthal gtts; usually only 1 single injection is needed for each eye; relatively inexpensive; shorter hsopital lenght of stay; myopia (eso severe) does not occur
Myopia in ROP
laser detroys factors responsible for development of anterior segment of the retina resulting in steeper curvature of the cornea, increased lense thickness, decreased anterior chamber depth; COKE BOTTLE GLASSES
longer follow up (56 wks)
although recurrence of ROP is less with bevac….
