Retinopathy of Prematurity: An Overview

Nakhleh E. Abu-Yaghi

Retinopathy of Prematurity: An Overview

Nakhleh E. Abu-Yaghi

Retinopathy of Prematurity (ROP)

A proliferative retinopathy affecting pre-term infants of low birth weight who have been often exposed to high ambient oxygen concentrations.

At 4th month of gestation, vascular complexes emanate from the hyaloid vessels at the optic disc and grow to the periphery.

They reach the nasal periphery after 8 months of gestation but do not reach the temporal periphery until 1 month after delivery most susceptible retina

Pathophysiology

Supplemental Oxygen exposure, while a risk factor, is not the main risk factor for development of this disease.

Restricting supplemental oxygen use does not necessarily reduce the rate of ROP, and may raise the risk of other hypoxia-related systemic complications.

Multiple factors can determine whether the disease progresses, including

overall health

birth weight

stage of ROP

Risks

Patients with ROP are at greater risk for strabismus

glaucoma

cataract

myopia later in life, and should be examined yearly to help prevent and treat these conditions

Diagnosis

Examination of the retina of a premature infant is performed to determined

how far the retinal blood vessels have grown (the zone)

the character of the leading edge of growing retinal blood vessels at the vascular-avascular border (the stage)

The extent of involvement in clock hours

Staging

The Stages describe the ophthalmoscopic findings at the junction between the vascularized and avascular retina.

Stage 1 is a faint demarcation line. Stage 2 is an elevated ridge. Stage 3 is extraretinal fibrovascular tissue. Stage 4 is sub-total retinal detachment. Stage 5 is total retinal detachment.

Stage 1

Stage 2

Stage 3

Stage 4

Stage 5

Extent of involvement is determined by the number of clock hours involved

Plus disease

Plus disease may be present at any stage.

It describes a significant level of vascular dilation and tortuosity observed at the posterior retinal vessels. This reflects the increase of blood flow through the retina.

Video…

Course

Although the clinical features of ROP usually take several weeks to develop, in rare instances the disease can progress from stage 1 to stage 4 within a few days

In about 80% of infants, ROP will regress spontaneously, leaving few if any residual disease

Spontaneous regression may even occur in patients with partial retinal detachments

Threshold disease Threshold disease is defined as disease

that has a 50% likelihood of progressing to retinal detachment.

Threshold disease is considered to be present when stage 3 ROP is present in either zone I or zone II, with at least 5 continuous or 8 total clock hours of disease, and the presence of plus disease.

Screening

Who should be screened?

Babies born before 31 weeks gestational age

Or weighing 1500g or less

When?

Between 6 and 7 weeks postnatal age or 34 weeks post conceptual age (whichever comes first), but not before 5 weeks post natal age, to detect threshold disease

Follow up

Q 2weeks or more frequently if case suggests rapid progression

Until when?

zone III retinal vascularization attained without previous zone I or II ROP if the postmenstrual age is more than 35 weeks.

full retinal vascularization. postmenstrual age of 45 weeks and no

prethreshold disease regression of ROP (Care must be taken to be

sure there is no abnormal vascular tissue present capable of reactivation and progression.

Treatment

1. Ablation of avascular immature retina by eithercryotherapy or laser photocoagulation is recommendedin infants with threshold disease,.

This is successful in 75% of cases, but the remaining 25% progress to retinal detachment in spite of treatment.

2. Vitreoretinal surgery for tractional retinal detachment3. Anti Angiogenesis therapy

The Early Treatment for retinopathy of Prematurity Study (ETROP) high risk pre-threshold ROP

Any stage Zone I ROP; Zone II stage 2 with plus disease, or stage 3 Zone II with less than 5 contiguous or 8

cumulative clock hours of stage 3 ROP with plus disease

Many things can wait… Children cannot