RETINOPATHY OF PREMATURITY - INTRODUCING ISOBEL
- Summary of condition
Isobel (pseudonym) was born premature at 23 weeks and 6 days with stage 3/4b ROP and needed emergency treatment in the hospital for detached retina. Both eyes had laser treatment but treatment to the left eye was unsuccessful. The right eye was stage 3 (plus disease) with enlarged and twisted blood vessels; surgery was successful. The left eye was partially detached and progressed to stage 4b and surgery was unsuccessful. Furthermore the laser treatment burned the periphery of the retinas leaving her with restricted visual fields. The residual scarring also left Isobel with various unspecified ‘blind spots’ across her peripheral right retina.
- What is ROP?
Retinopathy of prematurity (ROP) affects premature babies born before 31 weeks and the smaller the baby the higher the risk of it developing. In serious cases it leads to permanent visual impairment and blindness. The retina develops and matures in-utero but in premature infants the blood vessels of the retina are not fully developed. After a premature birth the blood vessels in the infant’s retina continue developing but in some cases abnormally. New abnormal blood vessels begin to grow. Because they are fragile and immature they proceed to leak in the retina and they leave behind scar tissue. In serious cases the scars can pull on the retina and cause the retina to detach from the eye. Several factors contribute to the disease developing, one of which is an excess of oxygen. ROP is associated with other eye conditions, especially squints, cataracts, glaucoma, myopia and nystagmus. In the majority of cases ROP resolves itself but in a small number of cases (as with Isobel) it needs immediate intervention to prevent blindness.
THE FIVE STAGES OF ROP
Stage 1 - Mild: Abnormal blood vessels grow in the retina. No treatment is needed. The child gains normal vision eventually. It resolves itself.
Stage 2 - Moderate: The blood vessels are slightly more abnormal. Many children do not need treatment and have normal vision in later childhood.
Stage 3 - Severe: blood vessels grow more abnormally. What makes this particularly severe is the growth of abnormal blood vessels in the centre of the eye instead of along the surface of the retina as is normal. In some cases no treatment is needed. If the blood vessels are enlarged and twisted (called ‘plus disease’) intervention is needed.
Stage 4 - Partly detached retina: the scar pulls away and bleeding occurs, abnormal vessels pulling the retina away from the wall of the eye.
Stage 5 - Fully detached retina: final stage. The retina pulls right away from the inner lining of the eye. With no intervention blindness may result.
Laser therapy "burns away" part of the periphery of the retina, which has no normal blood vessels. In doing this, laser treatment destroys the peripheral areas of the retina, slowing or reversing the abnormal growth of blood vessels. But the treatment also destroys some side vision. This is done to save the most important part of sight—the sharp, central vision.
- Isobel’s Vision
Isobel was born around 24 weeks with stage 3/4b ROP and needed emergency treatment in the hospital for a partially detached retina in the left and a potential detachment in the right. Both eyes had laser treatment (burning of the peripheral retina) but treatment to the left eye was unsuccessful. The left eye remains microphthalmic (small) and strabismic (squint) and sees very little; the right eye is myopic with restricted visual fields. To use her right eye she turns her head to one side to see.
- Visual acuity
Isobel has scarring on her retinas, the left eye being the most affected; it is microphthalmic (small, not fully developed), amblyopic (lazy) with a convergent strabismus (inward squint) and with scarring directly over the central vision. The left eye has light perception and no useful central vision. The retina of the right eye is scarred though less so and has a visual acuity of 6/48 (Snellen) or 0.90 (LogMAR). This is based on the Cardiff cards preferential looking test (she made no response to the Kay Picture test).
Isobel is functionally monocular with no useful vision in her left eye. Both eyes also have nystagmus (wobbly eyes). Nystagmus on its own can seriously reduce distance vision and is a condition that is exacerbated by fatigue, associated with focusing difficulties and causes the sufferer to take up to 25% longer over normal visual tasks. Patching has been suggested for the left strabismic eye but has not been implemented at home. Patching would in any case cause Isobel some distress, as it would render her functionally blind. She has been prescribed glasses for myopia but is not made to wear them consistently. Being monocular Isobel has neither depth perception nor three-dimensional vision.
Isobel turns her head to the right to look. She tends to trip and has some difficulty descending stairs. Isobel is light sensitive and reacts to glare and strong light. She brings objects a few inches distance from her face to examine them. She cannot identify people at all if they are more than five or six metres away.
- Near vision
Isobel is able to distinguish a visual target of 2-3cm in size at a distance of one metre. This is not perfect vision for a child of 2.5 years old but it is useful vision. Her near vision is significantly better than her distance vision. It will be necessary to ensure there is good spacing between all details she is presented with. Good separation between details and visual elements on a page is essential with nystagmus as letters and images can become blurred and merge together. Despite her myopia Isobel peers close to details to look. She is able to see a visual target equivalent to point size 18 at 15 cm. In an educational setting she will benefit from print and learning materials of approximately this size or preferably larger i.e. 24 (Arial font). This is practical in a nursery (and reception) setting as many books are already this size, but as the curriculum becomes more demanding it will require more and more adaptations on the part of the staff. Isobel will have difficulty sharing equipment and materials. Isobel will always need her own copy of a book and her own computer where necessary. She will need a big book for herself during story time.
- Eye contact
Isobel has difficulty making direct eye contact and turns her head to achieve her best vision as is often the case with nystagmus and monocular vision. This also has social implications: other children may wonder why Isobel does this and it may cause her to react by becoming withdrawn or to overcompensate by denying her condition. Isobel may sometimes approach others too closely and may need to be shown what is and what is not appropriate social behaviour.
Nystagmus creates an unsteady and blurred image on the retina that is caused by the constant involuntary eye movements. It reduces the clarity, resolution and sharpness of her vision to the extent that she is unable to recognise details such as a familiar face beyond 5metres. This will affect her ability to access texts on the board in an educational setting. Nystagmus is moreover a variable condition and a child can perform better or worse depending on factors such as fatigue, health, mood, stress and time of day. Isobel will need at some point to understand her own eye condition so that she can explain all about nystagmus and ROP to others. She will need to become her own advocate. The best way to deal with embarrassment about her visual impairment is to talk about it.
- Strategies - summary
I recommend the following modifications to the educational setting and curriculum:
- Extra practice with fine motor skills.
- A writing slope or upright easel.
- Adults should enhance the degree and quality of language they use with Isobel.
- Extra support in a low light environment.
- In the playground she would benefit from adult supervision.
- A multi-sensory approach to learning.
- Isobel will benefit from a clutter-free environment.
- Pictures and letters presented to Isobel should be big, bold and bright.
- Attention to be paid to contrast in her learning materials.
- She will benefit from enhanced lighting.
- Extra time for tasks because her eyes are slow in changing focus.
- Pre-teaching - adult to talk about activities in advance with her.
- Good structure, periods of quietness and calm, varied activities, a large play element.
- Awareness-raising with her class so they understand her visual needs and to avoid teasing.
- A mobility assessment.
- Specialist equipment such as a cctv (e.g. Professional Vision Services ‘Student’) and low vision aids (monocular and dome / bar magnifier).
- Laptop and training in touch typing at some point / from an early age.
- Technology such as a kindle or I-Pad for access to texts.
- Ongoing input in her educational settings from a qualified teacher for visual impairment (QTVI). Her teachers will require initial and additional training.
- The building will need an audit.
The Role of a learning support assistant for Isobel
- To ensure her safety.
- To sit with her during circle times and group sessions where the big book is used.
- To adapt learning materials
- To sit with her and point out what the teacher is writing
- A curriculum that is tailored and adapted to meet her needs.
NB For an expanded version of these strategies see post 6/12/22