Retinopathy of prematurity - laser treatment

When is treatment considered?

The ET-ROP study demonstrated improved visual outcomes with earlier laser treatment and has replaced previous guidelines set by the CRYO-ROP study.⁶⁻⁸

• Note the ET-ROP criteria for treatment emphasise the significance of "Plus disease" in Zones 1 and 2.

• Treatment is conducted for those eyes reaching Type 1 ROP (high-risk pre-threshold ROP that would normally progress to threshold ROP, if untreated).

  • Threshold ROP is defined as stage 3 ROP, Zone 1, or Zone 2 in 5 or more continuous clock hours or 8 cumulative clock hours with the presence of "plus disease".⁹⁻¹¹

• The aim of treatment is to reduce the incidence of retinal detachment and blindness.

• Laser therapy is the procedure of choice as it is less invasive and less traumatic to the eye and produces less discomfort to the infant¹².

  • Laser therapy uses a diode or argon laser light directed through the pupil onto the avascular retina to perform photocoagulation.

  • The laser burns cause destruction to the avascular retina, leading to diminished blood supply to the area and arrest of ROP progression.

• 15-20% of eyes with severe ROP will not respond, or respond poorly to laser treatment. It is important for both physicians and parents to understand that the treatment is not always effective.

• Successful laser treatment provides the infant affected by ROP with an improved chance to obtain better vision, but it does not mean that the child will necessarily have normal vision.

Preoperative and Intraoperative Care

Preoperative

1. Inform the parents about the need for surgery. Consent should be obtained by the operating ophthalmologist.

2. Preparation of the environment:

   1. Move the baby into a single room or evacuate or shield the other babies from the room where the operation 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 ray from exiting the room.

3. Preparation of the baby:

   1. Check FBC, electrolytes, and glucose to determine biochemical and haematological state, and correct any significant abnormalities.

   2. Baby should be nil by mouth for 4 hours prior to the set time of surgery. An intravenous infusion should be commenced.

   3. Move baby on to a heat table and place in the supine position.

   4. Intubate and ventilate baby to ensure a safe airway for a sedated infant.

   5. Give medication for sedation and analgesia. A fentanyl infusion is the preferred medication. Midazolam and morphine may be used as an alternative. Muscle relaxation with pancuronium may be required.

   6. Instill eye drops - 1 drop of amethocaine 1 % (or 0.4 % benoxinate), 1 drop of 0.5 % Tropicamide and 1 drop of 2.5 % phenylephrine to each eye 30 minutes prior to surgery, and the repeated 10 minutes later.

   7. Maintain baby on continuous monitoring and hourly recordings of:

      • cardiorespiratory status

      • blood pressure

      • SpO2

      • skin temperature

4. Preparation of attending staff members:

   1. All staff in the room must wear protective goggles throughout the procedure.

   2. Surveillance programmes for staff members involved are unnecessary as the laser spot is only 200 micrometres in size, there is a protective filter on the laser, and all staff should wear protective goggles.

   3. Preparation of equipment: The operating ophthalmologist will bring the equipment required for the laser treatment and will be responsible for its safe operation and maintenance. See ADHB Laser Safety Policy.

Intraoperative

Monitor vital signs and possible complications during the procedure.

Postoperative care

1. Wean from ventilation as able.

2. Maintain intravenous fluid therapy as prescribed. Restart enteral feeds when the baby wakes. Monitor for signs of feeding intolerance.

3. Continuous monitoring and hourly recording of cardiorespiratory status, blood pressure, SpO₂, and skin temperature.

4. Baby is nursed with eye shields for at least 8 hours to protect from light if on a heat table, or should be protected from direct light by a cover over the incubator.

5. Observe for oedema of the eyelids, infection, and intra-ocular bleeding.

6. Administer eye drops or ointment as prescribed - usually fusidic acid (Fucithalmic) 1 % eye drops BD for 3 days.

7. Keep parents informed of baby's progress.

8. Follow-up will be arranged by the ophthalmologist - the baby is usually reviewed in one week.