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Implementing ROP screening 1: The practical process
How the first two stages of ROP screening are organised in a NICU.
Screening for ROP needs to be effective, efficient and safe for the baby. To achieve this, the screening team must follow a number of key steps at each stage of the process In this video we consider stages one and two. In a second video we will consider stages three and four. Stage 1.
Before screening: The neonatal team, led by the neonatal nurse
undertakes preparation of the place, preterm baby and parents:
Place: The team identifies where in the NICU the examination will take place and sets it up appropriately.
Preterm baby: The team includes the baby on a list and dilates their pupils before examination.
Parents: The team informs them what their baby will undergo in the screening procedure, educates them about the possibilities and obtains their consent to undertake the screening. Before screening, firstly, it’s very important to follow the infection control policy of the unit hand washing between examining patients or wearing gloves, wearing a gown and so on. And this is because it’s very easy to transmit infection from one baby to another in the unit.
You need to check, before you start, that the equipment is ready and that it’s been sterilised and you also need to make sure that equipment is in place to monitor the vital signs of babies, particularly those who are unstable to alert you if they develop bradycardia or if they become apnoeic and stop breathing. It’s also very important that a list of the babies to be examined has been generated.
ideally by the neonatal nurse in consultation with the neonatologist, so it’s very clear which babies, who are currently in-patients, need to be screened as well as a list of babies who’ve been discharged who are coming back for screening and this is where coverage comes in and ensuring that all babies who should be screened are actually screened. Parents need to be informed in advance that screening is going to take place and, ideally, they should give written, informed consent for this to be done and also, ideally, they should have been given health education materials, written materials which are clear, understandable, and in the local language well in advance of screening , so they know what is coming.
Stage 2: During screening the ophthalmologist carries out a systematic examination and records their observations of the ROP stages. The neonatal nurse monitors the baby’s vital signs. There are several things that need to be checked before you actually start examining the retina for retinopathy of prematurity. So the first thing that you need to do is to check that the pupils are dilated. If the pupils are not dilated this may be for two main reasons, either the nurse has not put them in or not put them in properly, or more importantly she has put them in and the pupils have failed to dilate. And this can be because the iris vessels are dilated as part of severe retinopathy of prematurity.
So it can be a warning sign that there is severe ROP present. So if the pupils are not dilated, do not say to the nurse I’ll come back in a day or two to examine that baby. Put more drops in and come back half an hour later and if the pupils have dilated fine you can carry on. If they are still small, continue and just see what you can through the small pupil. Even if you can get a glimpse of plus disease, dilated blood vessels in the retina, this will be enough to tell you that this baby’s got severe disease. Some people examine the eye and hold the eyelids open with their fingers.
other people prefer to use a lid speculum which should be inserted after putting in topical anesthesia It’s very important that the eyes are examined in a systematic way so first the right eye and then the left eye and it’s advisable to look at the posterior pole first, to see whether the retinal blood vessels are dilated and are tortuous.
And look at the vessels in each of the four quadrants as they emerge from the optic disc, and then you can use that information to decide whether there is no plus disease at all, whether there is plus disease present, which means vessels in all four quadrants are dilated and tortuous, or the vessels in just two quadrants are dilated or tortuous, and that can be classified as plus disease. The next thing to do is to look at the peripheral retina. Usually people examine the temporal retina first and then the nasal, and this is done to see how mature the retinal blood vessels are.
What you want to check is to see whether the retinal blood vessels have reached to the ora serrata in the temporal periphery. If those vessels are mature then that means this baby is no longer at risk of retinopathy of prematurity. However, if the blood vessels have not reached the ora serrata, then that baby is at risk of ROP at a later date.
So the way to identify the area of retina that represents zone one is to identify the disc, to identify where you think the macula is - which can actually be quite difficult in preterm babies and then with your eye gauge the distance which is twice the distance from the optic disc to the macula going out towards the periphery and If ROP occurs within that distance then that’s ROP in zone one. When you look at the retina you need to look at all 360 degrees and it’s important to do this because in many eyes you can have zone one in some parts of the retinal periphery and zone 2 in other parts.
Or you may have zone 2 ROP in most of the retina but zone 3 in only one small limited area. So it’s very important that you look to elicit where ROP is occurring in the whole of the retinal periphery. So, having done that for the right eye you then do exactly the same for the left eye In summary Screening for ROP needs to follow a clear process before and during the screening. Before screening the team must ensure that the place is set up, the baby’s pupils are dilated and that the parents have provided their consent. During screening it is important that a careful step-by-step examination of the whole retina is carried out.
In this video, Professor Clare Gilbert explains the procedures involved in the first two stages of any ROP screening process – before and during the eye examination.
An ROP screening case study
The following case study highlights the importance of remaining alert about the risk factors for developing ROP, the importance of repeat examinations and appropriate and timely decision making.Mohamed was born in a high-resource setting at 24 weeks gestation with a birth weight of 625g. At 30 weeks he was well stabilised and a dilated funduscopic examination revealed an immature retina but with no clear demarcation line. There was also no plus disease. A repeat screening examination one week later demonstrated early ROP with a demarcation line (stage 1) at zone 1 in both eyes. One week after that, another repeat examination revealed striking progression of ROP. There was neovascularisation of the iris (NVI) with associated poor dilation. Funduscopic examination revealed plus disease and flat stage 3 disease with scattered haemorrhages along the junction of vascular and avascular retina.Informed consent for laser photocoagulation was obtained from Mohamed’s parents. Given the poor dilation and significant NVI, intravitreal anti-VEGF treatment was also discussed with the parents and presented as an option for treatment. Retinal laser photocoagulation was then performed at this time.Examinations over the next seven days revealed improvement in NVI. At 33 weeks, additional photocoagulation was performed. Further examinations over the next two weeks revealed improvement in the plus disease and the neovasucularisation.
Babies are not born with ROP but it develops after birth. Keeping in mind the complex screening process for this small baby, was the screening process effective?
This article is from the online course:
Retinopathy of Prematurity: Practical Approaches to Prevent Blindness
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Retinopathy of Prematurity: Practical Approaches to Prevent Blindness
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