Retinopathy of prematurity

Retinopathy of prematurity (ROP), initially described as retrolental fibroplasia one of the leading cause of blindness in children.
Despite advances in diagnosis and treatment, as medicine and technology advances and premature infants are surviving at earlier gestational ages, ROP continues to be a significant problem.
ROP results in disorganized growth of retinal blood vessels, which may lead to scarring and retinal detachment.

1. Retinopathy of Prematurity Dr RS Walpitagamage Registrar in Ophthalmology TH Kandy Sri Lanka

2. Disease Entity Retinopathy of prematurity (ROP), initially described as retrolental fibroplasia one of the leading cause of blindness in children. Despite advances in diagnosis and treatment, as medicine and technology advances and premature infants are surviving at earlier gestational ages, ROP continues to be a significant problem. ROP results in disorganized growth of retinal blood vessels, which may lead to scarring and retinal detachment.

3. Etiology ROP occurs in premature infants who are born before the retinal vessels complete their normal growth. Local ischemia plays a role, just as in other proliferative retinopathies like diabetic retinopathy and sickle cell retinopathy. Its incidence varies inversely with birth weight and gestational age. Oxygen has long been known to have a role in the disease process. Excessive oxygen can cause vaso -obliteration in the immature retina. Studies have shown that keeping the oxygen saturation at a lower level from birth can reduce the rate of advanced ROP

4. PATHOPHYSIOLOGY

5. Pathophysiology In utero, the fetus is in a hypoxic state in contrast to after birth. When infants are born prematurely, the growth of retinal vessels is stimulated by vascular endothelial growth factor (VEGF). However if the immature retina is exposed to ongoing hyperoxia, the vessels will stop growing. Over time, the avascular retina becomes ischemic and stimulates VEGF in some cases leading to arterial venous shunts and neovascularization.

6. Risk Factors Key risk factors Low birthweight (less than 1500 grams) Gestational age (32 weeks or less) Extended supplemental oxygen, although the exact role is not fully understood Suggested risk factors Intraventricular hemorrhage, respiratory distress syndrome, sepsis, white race, and multiple births.

7. Primary prevention Screenings of infants at risk with appropriate timing of exams and follow up is essential in identifying infants in need of treatment

8. Recommended Timing of First Exam Based on Gestational Age Gestational Age at Birth Postmenstrual (weeks) Chronologic (weeks) 23 weeks 31 8 24 weeks 31 7 25 weeks 31 6 26 weeks 31 5 27 weeks 31 4 28 weeks 32 4 29 weeks 33 4 30 weeks 34 4 31 weeks 35 4 32 weeks 36 4

9. Diagnostic procedures Following pupillary dilation using eye drops, the retina is examined using an indirect ophthalmoscope. The peripheral portions of the retina are pushed into view using scleral depression

10. Zones depict the location of the disease in the retina

11. The  International Classification of ROP (ICROP)  includes 5 parameters (1) Zone:  The  location  of the disease in the retina Zone I is the posterior retina within 60 degrees of the optic disc Zone II is a concentric circle extending from Zone 1 to the nasal ora serrata Zone III is the remaining temporal retina (2) Clock hours:  The  extent  of the developing vasculature that is involved quantified from 1-12 clock hours (3) Stage:  The  severity  of the abnormal vascular changes observed Stage 1: Demarcation line between vascularized and non-vascularized retina Stage 2: Demarcation line w/ elevation         Stage 3: Demarcation line with fibrovascular proliferation Stage 4a: Partial detachment of retina not involving fovea Stage 4b: Partial detachment of retina involving fovea Stage 5: Total retinal detachment (4) Plus disease:  Venular dilation and arteriolar tortuosity in the posterior pole  (5) Pre-plus disease  Abnormal-appearing vasculature that does not make criteria for Plus disease

12. ROP, Stage 1. Demarcation line between vascularized and vascular retina

13. ROP, Stage 2

14. ROP, Stage 3. Extraertinal fibrovascular proliferation.

15. ROP, Stage 4a. Partial detachment of the retina not involving the fovea.

16. ROP, Stage 4b. Partial detachment of the retina involving the fovea.

17. ROP, Stage 5. Total retinal detachment.

18. Pre-plus disease. Abnormal-appearing vasculature that does not meet criteria for Plus disease.

19. Management Ophthalmologists with adequate knowledge of ROP should perform retinal exams in preterm infants. The initial exam should be based on the infant’s age . Follow up recommendations were updated in 2006 by the American Academy of Pediatrics and depend on the location and stage.  Follow up of 1 week or less: Stage 1 or 2 ROP in zone I Stage 3 ROP in zone II Follow up of 1 to 2-weeks: Stage 2 ROP in zone II Regressing ROP in zone I Immature vessels in zone I

20. Follow up Follow up of 2-weeks: Stage 1 ROP in Zone II Regressing ROP in zone II Follow up of 2 to 3-weeks: Immature vessels in zone II Stage 1 or 2 in zone III Regressing ROP in zone III

21. TREATMENT Treatment is based on 2 multicenter trials: the Cryotherapy for Retinopathy of Prematurity (CRYO-ROP) trial and the Early Treatment for Retinopathy of Prematurity (ETROP) trial (CRYO-ROP Cooperative Group, 1988 and ETROP Cooperative Group, 2008) Laser photocoagulation is the preferred treatment of choice. If laser is not available, cryotherapy may be performed. Laser photocoagulation is performed when ROP reaches  type 1 pre-threshold  disease. It is important to diagnose aggressive posterior ROP (AP-ROP) and treat it immediately, as this form of ROP can rapidly progress to retinal detachment. Intravitreal injections of anti-vascular endothelial growth factor (Anti-VEGF) may cause rapid resolution of AP-ROP ( Mintz-Hittner et al., 2011). However, laser photocoagulation remains the standard of care for most cases of treatment requiring ROP.

22. Surgery If laser or cryotherapy fails to prevent progression of ROP and the patient develops a retinal detachment,  surgery (vitrectomy, scleral buckle)  may be performed. Results are best when done before the fovea has detached. Stage 5 ROP has a poor visual prognosis

23. Complications The most feared complication in ROP is retinal detachment or macular folds. There are a number of other complications related to this disease that can effect visual development. Myopia is a common finding in premature infants with our without ROP. Infants with regressed ROP also have an increased incidence of strabismus, amblyopia, and anisometropia.

24. REFERENCES https://eyewiki.aao.org/Retinopathy_of_Prematurity https://www.aao.org/topic-detail/retinopathy-of-prematurity--asia-pacific#figure7

25. Thank you https://www.slideshare.net/RasikaWalpitagamage