CLASSIFICATION OF RETINOPATHY OF PREMATURITY
The International Classification of Retinopathy of Prematurity grades severity of the disease by stages (0-5), location of the disease into zones (1-3) and extent of the disease based on the clock hours (1-12) .
Stages
Stage 0 - mildest form of ROP, with immature retinal vasculature and no clear demarcation of vascularized and nonvascularized retina
Stage 1 - fine, thin demarcation line with no height and thickness appears between the vascular and avascular retina.
Stage 2 - the white line widens into a broad, thick ridge clearly separating the vascular and avascular retina.
Stage 3 - neovascularisation grows into the vitreous on the ridge, on the posterior surface of the ridge or anteriorly toward the vitreous cavity and the ridge has a velvety appearance with a ragged border.
Stage 4 – sub-total retinal detachment beginning at the ridge where the retina got pulled anteriorly into the vitreous by the fibrovascular ridge
Stage 4A - partial retinal detachment not involving the fovea.
Stage 4B - partial retinal detachment involving the fovea.
Stage 5 - total retinal detachment in the shape of a funnel.
Stage 5A - open funnel.
Stage 5B - closed funnel.
Plus disease
”Plus disease” is an indication of activity and is characterised by the appearance of dilatation and tortuosity of the retinal vessels, iris vascular engorgment, pupillary rigidity, and vitreous haze.
Zones
The retinal blood vessels grow out from the optic disk, and the designation by zones corresponds to this vascular development pattern as shown in the diagram below.
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Retinopathy of Prematurity
Zone 1 – extends from the optic disc to a point double the distance from the disc to the fovea, a radius of 30°.
Zone 2 is a circle surrounding the zone 1 circle with the nasal ora serrata as its nasal border.
Zone 3 - the residual crescent anterior to zone 2
The extent of ROP is recorded as clock hours in each eye according to the relevant zone.

Regressed ROP
Regressed ROP may result in vitreoretinal sequelae producing vascular and retinal changes in the peripheral retina.

Source:CPG Retinopathy of Prematurity Dec 2005 MOH Malaysia

PREPARATION FOR TREATMENT OF RETINOPATHY OF PREMATURITY
PRE-OPERATIVE PREPARATION:
Preparation of the Parents
The premature baby has a potentially blinding condition, which needs urgent treatment and must be handled with the utmost consideration. The ophthalmologist should discuss the situation with the parents in detail.
Consent
Consent should be obtained by the treating ophthalmologist.
Ideal location for treatment
Neonatal unit is the best location as close supervision and monitoring throughout the procedure can be provided.
Preparation of the environment
1. Move the baby into a single room where the laser procedure is to be performed.
2. The room is closed to all visitors and staff members not looking after the baby.
3. A sign must be displayed on the doors indicating that a laser procedure is taking place and that no one should enter.
4. Doors and windows are shielded to prevent the laser light exiting the room.
Preparation of attending staff members
All staff in the room must wear protective goggles throughout the procedure.
Preparation of equipment
The ophthalmologist will bring the equipment required for the laser treatment and will be responsible for its safe operation and maintenance.
Preparation of the baby
1. Inform the paediatrician and prepare the baby.
2. Check full blood count, electrolytes, and glucose to determine biochemical and haematological state, and correct any significant abnormalities.
3. Baby should be nil by mouth for 4 hours prior to the set time of laser procedure. An IV infusion should be commenced.
4. Dilate the pupils fully by instilling eye drops : 1 drop of 0.5% cyclopentolate and 1 drop of 2.5% phenylephrine or gutt Cyclomydril (0.2%cyclopentolate and 1% phenylephrine) in each eye every 10 minutes 1 hour prior to procedure.
5. Move baby onto a heated table and place the baby in supine position.
6. Intubate and ventilate the baby to ensure a safe airway. Good sedation (e.g. fentanyl) and analgesia (e.g. fentanyl, morphine) during laser procedure are essential since laser treatment can be painful.
7. Maintain the baby on continuous monitoring and hourly recordings of cardio-respiratory status. Experienced staff must be in attendance until baby has fully recovered.
Intraoperative
Monitor vital signs and possible complications during the procedure.
Paediatric postoperative management
1. Wean off ventilation when stable.
2. Maintain intravenous fluid therapy as prescribed.
3. Restart enteral feeds when the baby wakes up.
4. Monitor for signs of feeding intolerance.
5. Continuous monitoring and hourly recording of cardio-respiratory status, blood pressure, SpO2, and skin temperature.
6. Baby is nursed with eye shield for at least 8 hours to protect from light if on a heated table, or should be protected from direct light by covering the incubator.
7. Observe for oedema of the eyelids, infection, and intra-ocular bleeding.
8. Administer eye drops or ointment as prescribed .
9. Keep parents informed of baby’s progress.
10. Follow-up appointments are to be stressed and scheduled accordingly.
Ophthalmic post-operative management
• Mydriatic, antibiotic and steroid drops instilled for a week.
• Examine the retina after a week by which time `plus’ disease should show the signs of regression.
• Re-treatment may be needed in selective cases especially if there is still active ROP it is probably not necessary to treat all skip areas.

GENERAL INFORMATION FOR PARENTS

Babies with birth weights less than 1500 gm or those born prematurely 8 weeks or more, should routinely have their eyes examined. This is done to pick up those infants who may develop a disease known as’ Retinopathy of Prematurity ‘(ROP)
It is important to understand that ROP is a common condition. Most babies only get a mild form of ROP which will resolve completely by itself without affecting the vision. But some babies may progress to advanced form of disease and require treatment. There are various methods of treatment available which are effective and successful.
Prematurity is the main cause of ROP, the more premature the baby is born the greater the risk of developing ROP. The use of oxygen has been implicated but a clear relationship between oxygen therapy and ROP has not been well established. The baby’s general condition may also play a role in the development of ROP.
ROP affects the development of blood vessels in the retina of the eye. The retina is the innermost layer at the back of the eye responsible for vision. The blood vessels are not fully developed as the baby is born prematurely. There is a possibility of development of abnormal blood vessels and progress to sight threatening complications. However, in mild forms of ROP, which are very common, vision is not affected and the babies will have complete recovery.
Screening of the premature babies helps in the early diagnosis of ROP especially those with severe ROP, which needs prompt treatment for good outcome.
The screening is usually carried out within a few weeks after birth, and is usually done before the baby has been discharged from the hospital. In some cases babies would need to come back to the eye clinic on an outpatient basis for further examination of the eyes. It is very important that regular examinations are carried out to monitor the progress of the disease and to administer the treatment if indicated.
Please ask your doctor for more information if you need any further information

Source:CPG ROP DEC 2005 MOH MALAYSIA