Optic Discs in Children With Cerebral Palsy
Condition: Cerebral Palsy
MeSH terms: Cerebral Palsy
Study type: Observational

Summary: 
      Hypothesis: Children born prematurely (between 8 and 9 months) with brain damage have an
      abnormal appearance of the optic nerve (nerve in eye) that resembles glaucoma (cupping)
      compared to those born before 8 months.

      Purpose: to see how often children who are born prematurely and have suffered brain damage,
      have abnormal appearance of the optic nerve (nerve in the eye) which mimics glaucoma
      (cupping). This optic nerve cupping is most often seen when children are born after 8 months
      and is rarely seen in children born before 8 months.

      Children born prematurely are known to have injuries to their brain as they are not yet fully
      developed. This often involves the part of the brain that involves vision. Clinicians have
      observed that these children have an abnormal appearance of the optic nerve (nerve in the
      eye), which has the appearance of glaucoma. These children often undergo extensive and often
      unnecessary invasive tests to rule out glaucoma. The investigators wish to establish the
      prevalence of this abnormality so that children are not subjected to unnecessary
      investigations. The investigators also want to understand how the optic nerve cupping
      (similar clinical picture as glaucoma) is related to the approximate timing and extent of the
      brain injury, the type of cerebral palsy and the motor disability of these children.
    

Detailed description: 
      This study will provide prevalence data on the occurrence of optic nerve head cupping in
      children with static encephalopathy in a much larger cohort than previously reported in
      literature (the largest cohort in literature is n=35). Children with a large optic nerve cup
      are treated as "glaucoma suspects". A routine glaucoma work-up in a child includes an
      examination under anesthesia or sedation, since children are unable to co-operate and stay
      still for accurate intraocular pressure measurements. These procedures often have to be
      periodically repeated and are a major financial burden. Importantly, they also carry
      substantial health risks, especially to the premature neonate who needs ICU monitoring after
      any anesthesia procedure. Roughly half of the children who undergo an examination under
      anesthesia for suspicion of glaucoma are found not to have the disease.

      Children with a diagnosis of static encephalopathy attending the Pediatric Neurology clinic
      will be recruited. Interested patients will undergo a routine dilated eye examination after
      obtaining the consent and assent. The optic nerve head parameters (size, shape, color,
      cup-disc ratio, vessel tortuosity) will be recorded by 2 ophthalmologists experienced in the
      evaluation of the optic nerve. Some of the children (who are physically able to sit up in a
      chair and look straight ahead without blinking) will be offered disc photographs. This will
      be a one-time examination done during the routine clinic visit.

      The prevalence of optic disc cupping (≥ 0.5) in a population of children with static
      encephalopathy with onset from 24-36 weeks will be obtained. Comparison of the cup/disc ratio
      in the 2 groups of children based on the approximate timing of the neurological insult will
      also be done.

      The results of this study may allow pediatric ophthalmologists and glaucoma specialists to
      spare a child with static encephalopathy and isolated optic nerve head cupping extensive,
      risky and expensive glaucoma work-up.

      This study will also provide more information on the patho-physiology of the developing
      visual nervous system.
    

Observational model: Cohort
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        Study population will include all children attending the pediatric neurology clinic and
        carry a diagnosis of static encephalopathy or equivalent terms- CNS malformation syndrome
        or cerebral palsy.
      
Keywords: optic disc cupping; cerebral palsy; static encephalopathy; optic disc; optic nerve; periventricular Leukomalacia