TRIPASS XR تري باس

 

371

William F. Deegan

Jayashree Ramasethu

Treatment of Retinopathy

of Prematurity

52

Retinopathy of prematurity (ROP), a disorder of developing

retinal blood vessels in the preterm infant, may lead to poor

visual acuity or blindness. Screening and timely treatment

improves visual outcomes.

A. Screening for ROP (1–3)

Guidelines for screening preterm infants for ROP are published and updated regularly (1–3). Recommendations for

screening in the United States are (1)

1. Infants with a birth weight of <1,500 g or a gestational

age of 30 weeks or less (as defined by the attending neonatologist).

2. Selected infants with a birth weight between 1,500 and

2,000 g or gestational age of more than 30 weeks with

an unstable clinical course, including those requiring

cardiopulmonary support and who are believed by their

attending pediatrician or neonatologist to be a high risk.

3. The timing of the first exam varies with gestational age.

The initial examination for infants born between 22

and 27 weeks’ gestational age is at 31 weeks’ postconceptional age (gestational age at birth plus chronological age). Infants born later than 27 weeks’ should be

screened initially 4 weeks after birth.

4. Follow-up exams depend on the retinal findings as classified by the International Classification of ROP (4).

Table 52.1 has been adapted from the joint policy statement of the American Academies of Pediatrics and

Ophthalmology, and the American Association for

Pediatric Ophthalmology and Strabismus (1).

5. Babies whose clinical condition deteriorates should be

followed closely (i.e., weekly), as late reactivation and

worsening are possible.

6. Binocular indirect ophthalmoscopy with scleral depression after pupillary dilation remains the gold standard

to accurately screen and monitor babies with ROP. The

exams are done at the bedside with the assistance of the

baby’s nurse.

7. Telemedicine screening with wide-field imaging has

been shown to have excellent sensitivity and specificity

in some centers (5).

B. Classification of ROP (4)

1. Location: Three zones based on concentric circles,

centered on the optic disc (Fig. 52.1)

a. Zone I: Circle whose center is the optic disc and

whose radius is twice the distance from the optic

disc to the center of the macula

b. Zone II: Circle whose radius extends from the optic

disc to the nasal ora serrata and is peripheral to

Zone I

c. Zone III: Temporal crescent of retina anterior to

Zone II

2. Extent of disease

The retina is divided into 12 equal segments, or

clock hours. The extent of retinopathy specifies the

number of clock hours involved.

3. Staging the disease (1,4) (Figs. 52.2 and 52.3)

a. Stage 1—Demarcation line: A flat white line in the

plane of the retina, separating avascular retina anteriorly from vascularized retina posteriorly

b. Stage 2—Ridge: Elevated fibrovascular tissue

extending out of the plane of the retina and separating the vascularized and avascular retina.

c. Stage 3—Extraretinal fibrovascular proliferation:

Neovascularization extending from the ridge into

the vitreous. This tissue may cause the ridge to

appear ragged or “fuzzy” (Fig. 52.2).

d. Stage 4—Partial retinal detachment: A separation of

the retina from the underlying choroid. Traction by

the vitreous, through the presence of neovascular

tissue, pulls the retina away from its underlying

attachments. The intervening (subretinal) space fills

with a proteinaceous fluid.

(1) Stage 4A: Detachment spares the macula.

(2) Stage 4B: Involves the macula

e. Stage 5—Total retinal detachment: Retinal tissue

becomes inextricably bound to reactive vitreous and

is pulled by the vitreous into the retrolental space

(hence the older term, retrolental fibroplasia).

4. Additional signs indicating severity of active ROP

a. “Plus” disease: Dilation and tortuosity of retinal vessels in at least two quadrants of the eye. This is seen