Retinopathy of prematurity

Question 1

Who does this condition affect?

Answer 1

Preterm and low birth weight babies.

Can typically affect babies before 32 weeks gestation.

Question 2

What is it?

Answer 2

Abnormal development of the blood vessels in the retina can lead to scarring, retinal detachment, and blindness.

Question 3

What is the pathophysiology?

Answer 3

• retinal blood vessel development starts at around 16 weeks and is complete by 37-40 weeks gestation
• the blood vessels grow from the middle of the retina to the outer area
• this vessel formation is stimulated by hypoxia, which is a normal condition in the retina during pregnancy
• when the retina is exposed to higher o2 concentrations in a preterm baby, particularly with supplementary oxygen during medical care, the stimulant for normal blood vessel development is removed
• when the hypoxic environment recurs, the retina responds by producing excessive blood vessels (neovascularisation), as well as scar tissue
• these abnormal blood vessels may regress and leave the retina without a blood supply
• the scar tissue may cause retinal detachment

Question 4

What are the 3 zones the retina is divided into?

Answer 4

• Zone 1 = optic nerve and the macula
• Zone 2 = from the edge of zone 1 to the ora serrata
• Zone 3 = outside the ora serrata.

Question 5

How are the retinal areas described?

Answer 5

As a clock face, e.g., there’s a disease from 3-5 o’clock.

Question 6

How are the areas of disease described?

Answer 6

From stage 1 (slightly abnormal vessel growth) to stage 5 (complete retinal detachment).

Question 7

What is ‘plus disease’?

Answer 7

Describes additional findings, e.g., tortuous vessels and hazy vitreous humour.

Question 8

Which babies should be screened for ROP?

Answer 8

Babies born before 32 weeks or under 1.5kg should be screened for ROP. It’s carried out by an ophthalmologist.

Question 9

When does screening start, how often, and when should it stop?

Answer 9

• 30-31 weeks corrected gestational age in babies born before 27 weeks
• 4-5 weeks of postnatal age in babies born after 27 weeks
• screening should happen at least every 2 weeks and cease once the retinal vessels enter zone 3, usually around 36 weeks gestation

Question 10

What is examined during screening?

Answer 10

• All retinal areas have to be visualised
• Screening involves monitoring the retinal vessels as they develop and looking for plus disease.

Question 11

What is the treatment?

Answer 11

Systematically targeting areas of the retina to stop new blood vessels forming. 1st line = transpupillary laser photocoagulation to halt and reverse neovascularisation.

Question 12

What are other treatment options?

Answer 12

Other options include cryotherapy and injections of intravitreal VEGF inhibitors. Surgery may be needed if retinal detachment occurs.