Retinopathy of Prematurity (ROP) (With acknowledgements to

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Retinopathy of Prematurity (ROP)
(With acknowledgements to the Online Journal of
Ophthalmology www.onjoph.com)
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Contents

• Introduction
• Epidemiology
• Incidence
• Pathogenesis and clinical features
• Classification of ROP
• Terminology
• Examination and screening
• Management
• Conclusion

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Introduction

• ROP ? potentially blinding
• ICROP and CRYO-ROP guidelines to screen,
  discuss and treat ROP.
• ?frequency of ROP
• 2 facets
• Acute phase normal vasculature goes awry ?
  abnormal vessel proliferation.
• Chronic phase late proliferation, retinal
  detachment and visual loss due to cataracts
  squints amblyopia etc.
• 90 acute ROP regress spontaneously.
  

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Epidemiology

• Cryo-ROP Incidence and severity correlates with
  LBW and early post-conceptual gestational age.
• ?Incidence of more severe posterior ROP in
  smaller and younger infants.
• Caucasians and Hispanics have ?aggressive ROP
  compared to African Americans.
• Mayet and Cockinos (CHBara) There is a similar
  incidence of ROP in Africans compared to other
  races but with less severity (3).

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Incidence

• Related to gestational age (GA) and birth weight
  (bw).
• ROP rare in bw gt 2000 grams.
• 70 ROP in bw lt 1250g and 7 develop threshold
  ROP.
• Threshold ROP very rare in bw gt 1250g. (Mayet
  Cockinos)
• 95 ROP begins at 32-34 weeks GA.
• Threshold disease at 36 weeks.
• Regression with spontaneous healing at 45-48
  weeks GA.
• Long term ophthalmic follow up of formerly
  premature neonates who suffered severe ROP.

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Pathogenesis and clinical features

• Incomplete retinal vascularisation.
• Vessels migrate from disc to ora at 16 weeks.
• Mature vessels extend to nasal ora at 36 weeks.
• Vessels extend to temporal ora at 39-41 weeks.
• STOP-ROP supplemental treatment of oxygen in
  progression of ROP did not yield statistically
  significant difference in the progression to
  threshold ROP.
• LIGHT-ROP Light reduction in ROP showed no role
  in the incidence or severity of ROP.

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Pathogenesis Cont.
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Classification of ROP

• International Classification of Retinopathy of
  Prematurity (ICROP)
• Describe ROP according to - Zone, Extent and
  Stage.

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Classification of ROP cont.

• Staging
• 5 stages - describe abnormal vascular response.
  Most severe stage is used to determine the stage
  of the eye as whole.

• Stage 1 Demarcation line

• Stage 2 Ridge

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Classification of ROP cont.

• Stage 3 Extaretinal Fibrovascular Proliferation
• Stage 4 Partial Retinal Detachment
• 4a - Extrafoveal
• 4b Foveal
• Stage 5 Total Retinal Detachment

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Classification of ROP cont.

• Plus disease
• signs indicating severity. Venous dilatation
  or arteriolar tortuosity in at least two
  quadrants vitreous haze poor pupil dilatation
  vascular engorgement of the iris.

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Terminology

• Threshold disease Stage 3 in zone 1 or 2 in at
  least 5 contiguous or 8 non-contiguous clock
  hours with plus disease. Point at which infant is
  treated.
• Pre-threshold disease ETROP. High and low risk
  prethreshold disease.
• High risk prethreshold
• Zone1, any stage ROP with plus disease.
• Zone 1, stage 3 with or without plus disease.
• Zone 2, stage 2/3 with plus disease.
• Rush disease Rapid progressive severe form of
  ROP. Posterior location. Dilated, tortuous
  vessels with shunt vessels throughout retina.

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Examination and screening

• Dilate with cyclomydril.
• Screening guidelines vary depending on resources,
  financial implications and medicolegal liability.
• Universal criteria for screening
• 1. Infants with bw lt 1500g or GA lt 31 weeks.
• 2. First examination 4/52 after birth.
• 3. Examine 1 or 2 weekly depending on stage
  of
• disease at initial visit.
• 4. Treat threshold disease.
• 5. Examine until 45 weeks GA without
  threshold disease
• or till vascularisation reaches zone 3.

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Management

• ETROP Cryo-ROP
• Treat threshold disease as it decreases
  unfavourable outcome from 15 to 9.
• Ablation is beneficial for prethreshold ROP.
• Photograph screening for ROP
• Telemedicine with on-site treatment.
• Evidence based screening criteria
• Screen at 31 weeks GA or 4 weeks chronologic
  age if born before 27 weeks.
• Continue screening till 45 weeks GA or
  vascularisation in zone 3.
• Screening of 1250g-1800g infants is cost
  effective.
• ETROP Recognize prethreshold disease and
  follow up 2 weekly.
• Follow up weekly if zone 2,
  stage 2 ROP or if
• vascularisation ends in zone
  1.

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Management Cont.

• Treatment of ROP
• Portable indirect laser units. Laser
  superior to cryotherapy.
• Rush disease
• Poor prognosis if found in zone 1. 64
  anterior zone 1 required surgery after laser.
  100 posterior zone 1 required surgery after
  laser treatment.
• ROP related retinal detachment
• misconceptions
• 1. Stage 4A benign and can wait till
  stage 4B before treating.
• 2. Poor prognosis with total detachment.
• Surgery reserved for stages 4A, 4B and 5.
• Intravitreal triamcinolone in Stage 5? ?
  reattachment success rate.
• Vision restoration technology future.

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Conclusion

• Ultimate prevention prevent premature births.
• The role of VEGF and IGF-1 may lead to
  pharmacologic interventions in preventing
  progression.
• Evidence based data reshape our understanding of
  who to screen and determines the critical timing
  of treatment.
• Digital fundus imaging may revolutionalise
  screening.
• ROP is a lifelong disease with sequelae
  manifesting into the 2nd decade.
• Surgical intervention preserves vision in
  ROP-related retinal detachment esp. before
  macular detachment.