Retinopathy of prematurity (ROP) is a disorder in premature infants where abnormal blood vessel growth occurs in the retina. The developing retina is susceptible after premature birth interrupts normal vessel development. Exposure to abnormal oxygen levels, either high or low, can further disrupt growth. ROP is evaluated based on location within the retina, severity of abnormal vessels, and presence of "plus disease". Screening allows early detection so treatment like laser ablation can be given if the disease reaches a threshold level with risk of vision loss. While ROP can cause complications like retinal detachment if untreated, screening and timely treatment helps prevent blindness.

1. RETINOPATHY OF
PREMATURITY

2. DEFINITION
• Retinopathy of prematurity ( ROP ) is a disorder of premature, low birth weight
infants featuring abnormal proliferation of the developing blood vessels at the retina
mostly related to injudicious supplementation of oxygen.

3. RETINAL VASCULATURE
• Choroid vascularizes at 6 weeks – 21 weeks. Retinal vascularization starts at ON head at 16 weeks. ( 4 months ).
• After 8 months of gestation retinal vessel reach nasal periphery of retina, they do not reach temporal periphery
until at term or by 1 month after delivery.
• The two phases of normal vascular development are characterized as vasculogenesis, from the 14th week until
the 21st week, and angiogenesis, beginning in the 22nd week and continuing until the retina is fully vascularized
after term.
• Vasculogenesis is triggered by primitive plexus, not VEGF dependant. During vasculogenesis, vascular precursor
cells (VPCs) exit from the optic nerve to form the four major arcades of the posterior retina.
• Angiogenesis is characterized by the proliferation of endothelial cells, arising from the existing vasculature
formed during vasculogenesis.

4. PATHOGENESIS
• Premature delivery interrupts normal vasculogenesis.
• Incompletely vascularized temporal retina is susceptible to O2 damage.
• Premature delivery frequently requires hyperoxic environment, reducing angiogenic drive halting the
vasculogenesis. ( Phase I )
• Sudden cessation in O2 causes hypoxia and overproduction of angiogenic factors such as VEGF. Leads to
angiogenesis overdrive. ( Phase II )

5. GRADING OF DISEASE
- LOCATION
- SEVERITY
- PRESENCE OF PLUS DISEASE

6. LOCATION
• Zone I: The area defined by a circle centered on optic nerve, the radius of which extends
from the center of the optic disc to twice the distance from the center of the optic disc to
the center of the macula.
• Zone II: The area extending centrifugally from the edge of zone I to a circle with a radius
equal to the distance from the center of the optic disc to the nasal ora serrata.
• Zone III: The residual temporal crescent of retina anterior to zone II. By convention,
zones II and III are considered to be mutually exclusive.

8. SEVERITY
• Stage 1: Demarcation Line
• Stage 2: Ridge
• Stage 3: Extraretinal Fibrovascular Proliferation: Neovascularization extends from the ridge into
the vitreous. This extraretinal proliferating tissue is continuous with the posterior aspect of the
ridge, causing a ragged appearance as the proliferation becomes more extensive.
• Stage 4: Partial Retinal Detachment
• Stage 5: Total Retinal Detachment

9. Demarcation line. A whitish line is visible between the normally vascularised retina and
the peripheral retina in which there are no blood vessels

10. Visible ridge. The demarcation line develops into a ridge, with height and width, between
the vascular retina and peripheral retina

11. Blood vessels in the ridge. Blood vessels grow and multiply (proliferate) and are visible
in the ridge

12. Sub-total retinal detachment

13. PLUS DISEASE
• Additional signs of increased venous dilatation and arteriolar tortuosity of the posterior retinal
vessels which can increase in severity to include iris vascular engorgement, poor pupillary
dilatation, and vitreous haze

15. SCREENING
Screening should be carried out for the infants with either of the following:
• Birth weight less than 1500 g or
• Gestational age less than 32 weeks or
• Infants with an unstable clinical course who are at high risk (as determined by the
neonatalogist or paediatrician)

16. The first examination should be done 4 to 6 weeks after birth since very early
examination may have no value.
Screening of all infants at risk of developing ROP should be continued regularly until:
• Retina is completely vascularised
• ROP has fully regressed and there are no signs of risk for visual loss
• ROP has progressed to a level of severity where treatment is indicated

17. If no signs of ROP Infants at risk should be screened at 2-3 week intervals until the
retina is fully vascularised.
If ROP is present
- Zone 1 : stage 1, 2 or 3 ROP without plus disease should be screened at least weekly
because there is a high risk of disease progression.
- Zone 2 : stage 1 ROP should be screened 2 weekly
- Zone 2 stage 2 ROP without plus should be screened 1-2 weekly
- Zone 2 stage 3 ROP without plus should be screened at least weekly

20. TREATMENT
• The principle of treatment is to remove the stimulus for growth of new blood vessels
by ablating the peripheral avascular retina. This will in turn reduce the incidence of
retinal detachment and consequent blindness.

21. WHEN TO INITIATE TREATMENT
Threshold disease of ROP ( CRYO-ROP study )
Defined as having all the following features
• Stage 3 ROP in zone 1, or zone 2
• Involving 5 or more contiguous clock hours; or 8 or more cumulative clock hours and
• the presence of plus disease .
With threshold disease there is a 50% predicted risk of blindness

22. CONT…
High risk pre-threshold disease of ROP (ET-ROP study )
Defined as any of the following
• Zone 1, any stage ROP with plus disease
• Zone 1, stage 3 ROP without plus disease or
• Zone 2, stage 2 or 3 ROP with plus disease
The early treatment of high-risk pre-threshold ROP significantly reduces unfavorable outcome.
The number of clock hours of disease is no longer a determining factor for treatment.

23. • Cryotherapy
• Laser Therapy ( Argon green and diode laser )
• Anti – VEGF
• Vitreoretinal surgery

24. COMPLICATIONS OF ROP
• Myopia ( 80% )
• Strabismus ( 23-47% ) and amblyopia
• Retinal detachment ( 22% )
• Refractive error
• Glaucoma

25. QUESTION 1
The following are true with regard to retinal neovascularization:
a. normal retinal neovascularization begins at 10 weeks'
gestation.
b. the temporal retina is the last to become vascularized.
c. vascularization of the nasal retina is complete at 36
weeks' gestation
d. both birth weight and gestational age of the baby are
important factor in the development of retinopathy of
prematurity
e. unless treated retinopathy of prematurity is a
progressive disease

26. FTTTF
• Normal retinal vascularization begins at 16 weeks gestation
• Vascularisation of the nasal retina is complete at 36 weeks and temporal at 40-45
weeks
• Spontaneous resolution can occur with retinopathy of prematurity

27. THE END