Chapter-05 ROP Classification

ROP:Classification

18 Retinopathy of Prematurity: A Text and Atlas

INTERNATIONAL CLASSIFICATIONOF ROP27

Zone I (Posterior pole or inner zone): Thelimits of zone I are defined as twice the discfovea distance in all directions from theoptic disc (Fig. 5.1).

Zone II: Extends from the edge of zone Iperipherally to a point tangential to thenasal ora serrata.

Zone III: It is a residual temporal crescentof retina anterior to zone 2.

Extent: The extent of the disease is codedby the number of clock hours with ROP. Theextent of the disease is further described ascontiguous clock hours of ROP or non-contiguous clock hours.

Staging the Disease (Fig. 5.2)(As defined by the ICROP)

ICROP Staging

ROP: stages Description

Stage 1 Demarcation lineStage 2 RidgeStage 3 Ridge with extra-Mild/Moderate/ retinal fibrovascularSevere ProliferationStage 4 Subtotal retinal detach

mentA A. Not involving maculaB B. Involving maculaStage 5 Total retinal detachment

Rush disease: Characterized by engorge-ment of the posterior pole vessels whosemost anterior development was still in the

Fig. 5.1: Depicts the zones in the fundus as described in the ICROP classification

ROP: Classification 19

posterior pole and it was associated withbroad anterior avascular retina.

Plus disease: Schaffer, Quinn and Jhonsonrecognized this feature when they noted thatposterior polar dilation and tortuosityconstituted an important sign related to theseverity of the disease. Associated with itwas the iris vessel dilation and engorge-ment, which resulted in poor pharmacolo-gical dilation of the pupil. This was calledthe plus disease (Figs 5.3A to C).

Stage 1 (Demarcation Line): This line is athin but definite structure that separates theavascular retina anteriorly from the vascula-rized retina posteriorly. There are recogniz-able abnormal branching or arcading ofvessels leading up to it. It is relatively flat,lies within the plane of the retina and iswhite in color (Fig. 5.4).

Fig. 5.2: Right eye showing interrupted extraretinal fibrovascular proliferation (9 clock hours cumulative)Left eye showing continuous extraretinal fibrovascular proliferation (3 clock hours cumulative)

Stage 2 (Ridge): The line of Stage 1 nowhas grown, has height and width, occupiesa volume, and extends up out of the planeof the retina. The ridge may change in colorfrom white to pink (Fig. 5.5).

Stage 3 (Ridge with Extraretinal Fibrovas-cular Proliferation): To the ridge of stage 2is added the presence of extraretinal,fibrovascular proliferative tissue (Fig. 5.6).

Stage 4 (Retinal Detachment): It may becaused by an exudative effusion of fluid,traction, or both, even in this early stage.

Stage 4A. Subtotal retinal detachment notinvolving the macula (Fig. 5.7).

Stage 4B. Subtotal retinal detachmentinvolving the macula (Figs 5.8 and 5.9).

Stage 5: Total tractional retinal detachmentis always funnel shaped and is based on


Fig. 5.4: ROP stage 1 demarcation line

Fig. 5.5: ROP stage 2 ridge

Fig. 5.6: ROP stage 3 extraretinal fibrovascularproliferation

Fig. 5.3A: Mild plus disease

Fig. 5.3B: Moderate plus disease

Fig. 5.3C: Severe plus disease


configuration of the funnel (Figs 5.10 and5.11).

Funnel (Figs 5.12A to D):Anterior Posterior

i. Open Openii. Narrow Narrow

iii. Open Narrowiv. Narrow Open

PRETHRESHOLD ROP (FIGS 5.13)

Prethreshold ROP28 is defined as:

Fig. 5.7: ROP stage 4A subtotal tractionalretinal detachment

Fig. 5.8: ROP stage 4B subtotal tractional retinaldetachment

Fig. 5.9: ROP stage 4B subtotal tractional retinaldetachment

Fig. 5.10: ROP stage 5 total tractional retinaldetachment

Fig. 5.11: ROP stage 5 total tractional retinaldetachment


Figs 5.12A to D: Funnel configurations in Stage 5 ROPA. Anterior-Open; Posterior-OpenB. Anterior-Open; Posterior-NarrowC. Anterior-Narrow; Posterior-OpenD. Anterior-Narrow; Posterior-Narrow

1. Any stage of ROP in zone I with plusdisease

2. ROP stage 3 with plus disease with 3contiguous or 5 interrupted clock hoursof involvement of retina in zone II butless than threshold.

ETROP Study (Early Treatment of ROP)Sub-classification29

Type 1 ROP defined as zone 1 ROP, anystage ROP with plus disease; zone 1, stage3 ROP without plus disease; or zone 2, stage2 or 3 ROP with plus disease- perform retinal

ablation.

Type 2 ROP defined as zone 1, stage 1 or 2ROP without plus disease or zone 2, stage 3ROP without plus disease. These eyes should

be considered for treatment only if they progress

to type 1 or threshold ROP.

THRESHOLD DISEASE

This is defined as:Zone I or II: ROP stage 3 more than 5contiguous or 8 cumulative clock hours withplus disease present.

This is the stage in which the treatmentis mandatory since the chances of progres-sion to retinal detachment are 50 percent ifleft untreated (Figs 5.14 and 5.15).


Figs 5.13A to C: Stage 2, zone 2 mild plusROP (Prethreshold type 1) (17 June)

Figs 5.13D and E: Spontaneously regressing Stage 2, zone 2 mild plus ROP(Prethreshold type 1) at 6 weeks follow-up (5 August)

Birth weight 1.135 kgGestational age 28 weeks,Postconceptional age 35 weeks,Normal vaginal delivery, twins,History of respiratory distress, jaundice, blood transfusion 3 times, sepsis +


Birth weight 1.100 kgGestational age 28 weeks,Postconceptional age 35 weeks,Normal vaginal delivery, twinsHistory of respiratory distress, jaundice, blood transfusion 3 times, sepsis +

Figs 5.14A to C: Right eye Stage 3, zone 1moderate plus ROP (17 June)

Figs 5.14D to F: Left eye Stage 3, zone 1moderate plus ROP (17 June)


Figs 5.15A and B: Right eye Stage 3, zone 1 severe plus ROP (17 July)

ICROP REVISITED

An international group of pediatric ophthal-mologists and retinal specialists hasdeveloped a consensus document thatrevises some aspects of ICROP. Fewmodifications were felt to be needed. Theaspects that differ from the originalclassification include introduction of (1) theconcept of a more virulent form of retino-pathy observed in the tiniest babies(aggressive, posterior ROP), (2) a descrip-tion of an intermediate level of plus disease(pre-plus) between normal posterior polevessels and frank plus disease, and (3) apractical clinical tool for estimating the extentof zone I.

Pre-Plus disease is defined as vascularabnormalities of the posterior pole that areinsufficient for the diagnosis of plus diseasebut that demonstrate more arterial tortuosityand venous dilatation than normal and maylater progress to plus disease.

Aggressive posterior ROP is a new term forRush disease or type 2 fulminant ROP in whichthere is posterior pole vessels show increaseddilatation and tortuosity in all 4 quadrantsout of proportion to peripheral retinopathy,progresses rapidly, does not progress throughclassic stages 1-3 and may appear only as aflat network of neovascularization at thedeceptively featureless junction of vasculari-zed and non-vascularized retina.

Birth weight 1 kg,Gestational age 28 wks,Postconceptional age 36 wks,Normal vaginal delivery, twinsHistory of birth asphyxia and received O2, neonatal jaundiceKept in nursery 1 month, referred from other hospital

Chapter-05 ROP Classification

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