Retinopathy Of Prematurity

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Retinopathy Of Prematurity

• ROP

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• The term Retinopathy Of Prematurity was first
  suggested by Heath in 1952

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ROP

• Retinopathy Of Prematurity is a disorder of
  retinal blood vessel development in the premature
  infant.
• The severe form is characterized by retinal
  vascular proliferation, scarring, retinal
  detachment, and blindness.

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ROP Causes

• Major Cause
• Prematurity It affects prematurely born babies.
• All babies less than 1500 g birth weight or
  younger than 32 weeks' Gestational Age (GA) at
  birth are at risk of developing ROP.

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ROPRisk Factors

• Gestational age less than 32 weeks
• Birth Weight less than 1500 gm especially less
  than 1250gms
• Oxygen therapy Excessive oxygen use
• RefThe National Medical Journal of India 1996
  9(5) 211-4.

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Contd

• Other factors
• Sepsis,
• Multiple blood transfusions,
• Multiple births,
• Hyaline membrane disease,
• Use of aminophylline, antibiotics,
• Apnoeic spells,
• Low pH,
• Ultraviolet light therapy, etc

RefThe National Medical Journal of India 1996
9(5) 211-4.
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ROP Symptoms

• Results of severe ROP and premature birth may
  produce some of the following signs
• White pupils (Leukocoria)
• Abnormal eye movements (Nystagmus)
• Crossed eyes (Strabismus)
• Severe nearsightedness (Myopia)

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Changing Incidence of Severe ROP in
Industrialized Countries, and Survival Rates of
Low Birth Weight Babies.
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Normal Eye Development

• From 16 weeks to birth, retinal blood vessels
  grow out from the optic nerve to reach the
  peripheral retina. 
• The last twelve weeks of a normal 40 week
  gestation are crucial in the development of fetal
  eyes.

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Development In premature babies

• In premature infants, the normal growth of blood
  vessels stops.
• The area without adequate blood supply emits a
  chemical trigger to stimulate growth of the
  abnormal vessels.
• These vessels lead to a formation of a ring of
  scar tissue attached to both the retina and the
  vitreous gel that fills the center of our eyes.
• As the scar contracts, it may pull on the retina
  creating a retinal detachment.

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• Regardless of the gestation age at birth, ROP
  seems to occur at about 37 to 40 weeks.

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Severity of the disease

• Stage 1
• Demarcation Line
• A line that is seen at the edge of vessels,
  dividing the vascular from the avascular retina.
• Retinal blood vessels fail to reach the retinal
  periphery and multiply abnormally where they end .

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Stage 2

• Ridge
• The line structure of stage 1 acquires a volume
  to form a ridge with height and width.

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Stage 3

• Ridge with extra-retinal fibrovascular
  proliferation
• The ridge of stage 2 develops more volume and
  there is fibrovascular proliferation into the
  vitreous.
• This stage is further subdivided into mild,
  moderate and severe, depending on the amount of
  fibrovascular proliferation

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Stage 4

• Partially detached retina.
• Traction from the scar produced by bleeding,
  abnormal vessels pulls the retina away from the
  wall of the eye.

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Stage 5

• Completely detached retina and the end stage of
  the disease.
• If the eye is left alone at this stage, the baby
  can have severe visual impairment and even
  blindness.

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ROP Anatomical Location

• The area of the retina affected by ROP is divided
  into three zones

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Zone 1

• It is the most centrally located, and ROP
  develops in this zone if the retina in this area
  is most underdeveloped
• Zone 1 is more severe compared with disease
  limited to zones 2 or 3

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Zone 2

• It is the intermediate zone where blood vessels
  often stop in ROP

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Zone 3

• It is the peripheral zone of the retina, where
  vessels are absent in ROP, but present in normal
  eyes.

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ROPLocation of Zones
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ROPDiagnosis

• The only way to diagnose that baby has ROP is an
  eye exam by an ophthalmologist at 4 weeks of age.

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ROP Treatment

• Treatment for ROP depends on the stage and
  severity of the condition.
• The milder stages of the disease typically
  resolve themselves on their own, and do not
  require treatment.
• If the disease has progressed to a point where
  the baby's vision is at risk, treatment is
  required

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Treatment Modalities

• The treatments goal is to destroy the retina
  that is deprived of retinal vessels.
• This helps to shrink the new vessels and prevents
  the formation of dense scars that usually follow

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Laser Photocoagulation

• Laser photocoagulation is the most common
  treatment modality.
• A laser is directed to a designated spot to
  destroy abnormal vessels and seal leaks.
• Laser photocoagulation is the preferred method of
  treatment by surgeons, because there is little
  postoperative pain and swelling

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Cryotherapy

• Cryotherapy can be used to treat threshold ROP
  but is not the preferred
• It involves destroying abnormal tissue by
  freezing and is often used to treat Grade III ROP
• Cryotherapy reduces the risk for retinal
  detachment from 43 to 21.
• Drawback
• Cryotherapy also causes significant swelling of
  the eye and eyelid, which makes postoperative
  assessment difficult.

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Other treatments

• Scleral buckle and vitrectomy are also commonly
  used for severe stage 4 and stage 5
  retinopathies.
• Vitrectomy
• This is a complex procedure, which involves
  the use of microscopic instruments to remove the
  vitreous from the eye and replace it with a
  saline (salt) solution.

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ROPComplications

• Poor vision
• Myopia
• Premature infants with ROP have a high risk for
  strabismus and amblyopia.
• Infants with regressed ROP are at risk for eye
  problems as they grow. These are called late
  complications of ROP
• Those with Stage V also have a 30 risk for
  developing angle closure glaucoma.

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Prevention

• The most effective prevention of retinopathy of
  prematurity is prevention of premature birth

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Discussion

• The incidence of ROP in moderately premature
  infants has decreased dramatically with better
  care in the neonatal intensive care unit.
• However, this has led to high rates of survival
  of very premature infants who would have had
  little chance of survival in the past.
• Since these very premature infants are at the
  highest risk of developing ROP, the condition may
  actually be becoming more common again.