RETINOPATHY OF PREMATURITY

Dr Paavan KalraDepartment of Ophthalmology

S P Medical CollegeBikaner

INTRODUCTION

• Disease of retinal vasculature in immature retina of a premature neonate

• Results from interruption of normal vascularization

• Characterized by vaso-obliteration/ vaso cessation followed by abnormal neovascularization and ultimately cicatrisation

• Leading cause of childhood blindness in US

• Epidemic in low to middle income countries like India – ‘THE THIRD EPIDEMIC’

• VISION 2020

LANDMARK STUDIESCorroborative study for role of O2 -

1950s

ICROP - 1984, 1987, 2005

CRYO ROP

ETROP

LIGHT ROP

STOP ROP

HOPE ROP

PHOTO ROP

BEAT ROP

EMBRYOLOGY

Retinal Vascularization begins – 16 weeksPhase 1 – vasculogenesis – posterior pole

21-22 weeksPhase 2 – angiogenesis - progression to ora serrata

Nasal ora – at term (37th week PMA)Temporal ora – 38th week PMA (post

natal)

Choroidal Vascularization complete by 21 weeks

• Hypoxic state in utero - mixed venous bloodPaO2 = 25 mm Hg VEGF

• Placental IGF 1

• Functional maturation of photoreceptors and visual pathways at 28 to 32 weeks PMA. Increase in metabolic demand at 28 to 32 weeks

PATHOGENESIS OF ROP• Premature birth relative hyperoxia

(PaO2 = 60-80 mm Hg - low VEGF) Low IGF

• PHASE I – birth to 32 weeks PCA Vaso cessation

• PHASE II – after 32 weeks PCA - relative hypoxia (high VEGF and low IGF) Vaso proliferation

• REGRESSION / CICATRIZATION - >38 weeks PCA (decrease in VEGF and increase inTGF beta)

IMMATURE VASCULARIZATION

ACUTE ROP

REGRESSION

CICATRICIAL DISEASE

INCOMPLETE VASCULARIZATION

COMPLETE VASCULARIZATION

RISK FACTORS• Three crucial risk factors:

– Birth weight– Gestational age– Number of days oxygen administered

• Other risk factors:– Multiple births– Blood transfusions– Intra Uterine Growth Retardation (IUGR) – Failure of increase in weight– Respiratory Distress Syndrome (RDS)– Fluctuations in Sa O2– Multiple apneic episodes– Hypercarbia, Acidosis– Sepsis– Intra Ventricular Hemorrhage (IVH)– Vit E deficiency– Anemia– Seizures.

CLASSIFICATION

• ZONE

• EXTENT

• STAGE

• PLUS

ZONES

EXTENT

STAGEStage 0 Immature Vascularization

Stage 1 Line of demarcation

Stage 2 Ridge of elevated tissue

Stage 3 Extra retinal fibrovascular proliferation (neovascularization)

Stage 4 Partial retinal detachment

4a Macula spared

4b Macula involved

Stage 5 Total retinal detachment

Open Open Funnel

Open Narrow Funnel

Narrow Open Funnel

Narrow Narrow Funnel

STAGE 0 : IMMATURE VASCULARIZATION

STAGE I : DEMARCATION LINEWhite in color

Abnormal branching or arcading of vessels posteriorly

STAGE II : RIDGE

Popcorn Isolated tufts of neovascular tissue posterior to ridge level of retina

White to pink

STAGE III : EXTRA RETINAL NEOVASCULARIZATION

MILD MODERATE SEVERE

STAGE IV a STAGE IV b Macula Spared Macula involved

STAGE IV : PARTIAL RETINAL DETACHMENT

• STAGE IV RETINAL DETACHMENT-Exudative, if early-Tractional, as part of the change over from acute to cicatricial disease. -Rhegmatogenous detachments, years later

STAGE V : TOTAL RETINAL DETACHMENT

PLUS• posterior venous dilation and arteriolar

tortuosity of at least 2 quadrants• Arises gradually or very rapidly.• Due to AV shunting mainly in ridge tissue• Severity indicator

• Often associated iris vessel engorgement miosis resistance to dilating medications vitreous hazetunica vasculosa lentis

Preplus disease: vascular abnormalities of the posterior pole more than normal, less than PLUS

The newly accepted preplus serves as a warning

CLINICALLY SIGNIFICANT TERMS• Threshold ROP: CRYO ROP study

Zone I stage III with PlusZone II Stage III with Plus( 5 contigous or total 8 clock hours)

• Prethreshold ROP: ETROP studyHigh risk Prethreshold

Zone I Stage I, II, III with plus Stage III without plusZone II Stage II and III with plus

Plus disease has increased in importance while the extent (clock hours) of disease has diminished

• AP-ROP: aggressive posterior ROP

-Earlier known as ‘RUSH Disease’

-posterior location,

-rapidly evolving preplus and plus disease neovascularization that may be subtle or even intraretinal in nature.

-Progress to stage IV & V in 2-3 weeks without passing through characteristic stages II and III

- requires laser treatment more than once

TREATMENT

• RETINAL ABLATION– CRYO– LASER

• SCLERAL BUCKLING

• VITRECTOMY– LENS SPARING– With LENSECTOMY

• Under GA• Distance from ridge to limbus noted• Applied to the anterior avascular area wherever ridge is

present• Ridge avoided• SPOTS – Preferrably Transconjunctival

Contiguous15 – 30End point – creamy whiteCopious irrigation

• Delivered through INDIRECT OPHTHALMOSCOPE + 28D• Ridge Avoided• SPOTS

Size =100 micronsHalf burn width apartEnd point – grade II gray burn

After LASER treatment• zone 2 ROP – generally regresses after a single treatment session.

• APROP– may regresses but can reactivate with return of plus

disease – progressive posterior hyaloidal contraction, and

progression to tractional posterior retinal detachment – Post-treatment vigilance is necessary

AP ROP : Treatment in 2 StepsIst – upto Flat Neovascular FrondsIInd – after regression of Fronds

(area beneath fronds continue to remain source of VEGF and hence reappearance of disease)

SCLERAL BUCKLEUnder GAPeritomy2.5 mm encircling band passed beneath 4 RectiOne anchoring mattress suture applied in all quadrantsRemoval after 3-6 months

VITRECTOMYNecessary in advanced casesLensectomy avoidedPeeling of membranesRelieve of tractionNo attempt to drain Sub Retinal Fluid

AIM : Ambulatory vision ie being able to see objects and move around a room without stumbling or bumping into obstacles.

REGRESSION

Involution or disappearance Gradual, can be very prolongedDifficult to recognize early in its course

CLASSIFICATION OF CICATRICIAL MACULAR CHANGES

MACULAR SCORE ANATOMICAL DEFINITIONMS-0 NormalMS-1 Macular ectopia MS-2 Macular foldMS-3 Macular detachmentMS-4 Total detachment

MACULAR ECTOPIA MACULAR FOLD

SCREENING

INTERNATIONALBirth Weight <1500 gGA < 32 weeksHigher BW/GA with risks(unstable babies)

31 weeks PCA or 4 weeks CA, which is later

INDIANBW <1500 g / 1750 gGA < 34-35 weeksHigher BW/GA with risks(unstable babies)

31 weeks PCA or 4 weeks CA, which is earlier(VLBW babies at 2-3 weeks CA)

RECOMMENDATIONS

• Neonatal ICU

• Combined to neonatal checkup

• Monitoring of systemic status

• Antisepsis

• Warm, dry and fed

• Pupillary Dilation : 2.5% phenyl ephrine + 0.5% Tropicamide – Twice, 15 mins apart 30 mins before exam

• Speculum

• INDIRECT ophthalmoscope ( with small pupil attachment ), 28/30D lens, scleral depressor

• PLUS DISEASE to be looked for before speculum and scleral depression

END OF SCREENING• COMPLETE VASCULARIZATION

• VASCULARIZATION in ZONE III (till 1 DD of temporal ora) – if no previous ROP in zone I & II

• REGRESSED ROP ( b/w 40 -44 weeks PCA)– no active disease left

• 45 weeks PCA with less than pre threshold disease

RETCAM• WIDE FIELD CONTACT RETINAL PHOTOGRAPHY – 130 deg

• Easy use by nurses and technicians• Eliminates inter observer variability• Teaching tool• Overcomes logistics of screening• More cost effective than examination• Tele ophthalmological screening

• “REFFERAL WARRANTED ROP”

• PHOTO ROP• KID ROP

Fluorescein Angiography can be done

OPTICAL COHERENCE TOMOGRAPHY

THANK YOU