Retinopathy of prematurity is a vascular-proliferative disorder of retina in preterm infants
Classification
Based on International Classification of ROP (ICROP)
Zones of ROP
Stages of ROP
Stage
5a - open funnel - optic disc visible under ophthalmoscopy
5b - closed funnel - optic disc not visible under ophthalmoscopy
5c - stage 5b + anterior chamber changes like uveitis, iridocorneolenticular adhesions
Plus disease
Severity Classification
Aggressive ROP
- developing rapidly from stage 1 to stage 5
- no typical progression of stages
- typically present in zone 1 or posterior zone 2
Screening of ROP
Parameters for consideration
- Birth weight
- Gestational age at birth
RBSK criteria for screening
- born at 34 weeks or less
- gestational age not know conclusively or birth weight below 2000 g
- born at 34–36 weeks + any of the following risk factors
- need for respiratory support
- oxygen therapy for more than 6 hours
- sepsis
- episodes of apnea
- need for blood transfusion
- need for exchange transfusion
- Admission into NICU/SNCU can be taken as a surrogate risk factor
AIIMS criteria for screening
- born at 32 weeks or less
- gestational age not know conclusively or birth weight below 1500 g
- born at 32–35 weeks + any of the following risk factors
- need for respiratory support
- oxygen therapy for more than 6 hours
- sepsis
- episodes of apnea
- need for blood transfusion
- need for exchange transfusion
- Admission into NICU/SNCU can be taken as a surrogate risk factor
How often to screen
- 32 weeks of PMA or 4 weeks of PNA whichever is later
- If born less than 28 weeks or birth weight less than 1200 g ROP to be done at 2-3 weeks of PNA
Follow up
- every 1–2 weeks depending upon the staging
- Screening can be stopped once vascularization is complete (around 40–44 weeks PMA) or if ROP shows regression
How to dilate
- Phenylephrine 2.5% + Tropicamide 0.5%, 2 times at 10 minute interval, 30 mins before examination
Treatment
Ablation of peripheral avascular retina thereby reducing the hypoxic drive of retina
| ROP Type | Management |
|---|---|
| Type 1 | Management needed |
| Type 2 | serial follow-up |
| A-ROP | Management needed |
Laser treatment
- should be done in NICU
- with double frequency YAG laser
- done in GA with cardiac monitor (in resource limited setting 2 mcg/kg bolus followed by 2 mcg/kg/hr of fentanyl can be an alternative)
- both eyes can be ablated in same setting
- followed after 5–7 days and thereafter weekly till signs of regression
Anti-VEGF Drugs
- Bevacizumab or Ranibizumab injection into vitreous chamber
- increased risk of reactivation as compared to laser therapy
- complications include
- retinal detachment
- persistent avascular retina
- macular anomalies
- glaucoma
- vitreous hemorrhage
Vitreoretinal surgery
- For advanced ROP (stage 4 and 5)
- Stage 5 ROP carries a poor prognosis
Regression
2 types
- Spontaneous Regression
- Treatment induced regression
- can be seen 1-3 days of Anti-VEGF and 7-14 days of laser therapy
- rest of retina can vascularize normally or arrest of vascualrization (Persistent Avascular Retina-PAR) can occur
Reactivation
- common with monotherapy of Anti-VEGF; rare with laser therapy
- peripheral avascular retina remain viable and produce VEGF
- This causes reactivation after phase of regression
- occurs between 37-60 weeks PMA
- can be seen in original site or different site
Prevention
- Antenatal steroids - reduce RDS and IVH, both are known risk factors of ROP
- Delayed cord clamping - reduces need of blood transfusion
- Temperature regulation
- Gentle respiratory management
Interventions in neonatal unit - POINTS of care
- Pain Control - use of swaddling and oral sucrose
- Oxygen Management - maintain oxygen saturation between 91-95%
- Infection control
- Nutrition
- Temperature control
- Supportive care