RETINOPATHY OF PREMATURITY (ROP)

• ROP was once described as retrolental fibroplasia (RLF), which is a descriptive term of scar formation behind the eye lens. During the 1940’s and 1950’s, reducing the amount of supplemental oxygen delivered to infants showed a decline in ROP, but also an increase in mortality and cerebral palsy. “ROP occurs in 25 to 35% of preemies up to 35 weeks gestation, with 5 to 10% having stage 3 or m ore and 3 to 5% resulting in blindness.”

• At around 16 weeks, the developing fetus with have retinal capillaries start to branch out. These capillaries “begin from the optic nerve and grow toward the ora serrate, the retina’s anterior end.” It takes almost 40 weeks for the capillaries, and expanded arteries and veins, to reach the entire ora serrate.

• The extrauterine environment is hyperoxic relative to the intrauterine environment. Retinal vessels will start to constrict and their growth is reduced in the presence of high PaO2. If the constriction is not relieved, the vessels will start necrosis, or vaso-oliberate. The un-necrosed vessels will then start to proliferate in an “attempt to reestablish a blood supply to the retina. The proliferation may extend into the liquid portion of the eye, the vitreous, where the vessels hemorrhage.” Scar formation of the retina will occur, and then traction, detachment, and blindness may also occur.
• ROP usually develops from several factors, not just one underlying factor. “These factors include immaturity, hyperoxia, hypoxia, blood transfusions, intraventricular hemorrhage, apnea, infection, hypercarbia, PDA, prostaglandin synthetase inhibitors, vitamin E deficiency, lactic acidosis, prenatal complications, and genetic factors.” Bright lights, maternal diabetes, maternal preeclampsia, heavy maternal smoking, duration of intubation, hypotension, and necrotizing enterocolitis & vitamin E deficiency are also contributing factors for ROP.

• ROP is classified into five stages, stage one being the least harmful, and stage five the most harmful.
• “Stages 1 and 2 customarily get better on their own. Some eyes, however, go on to
• Stage 3 retinopathy of prematurity. This happens when new blood vessels start to grow from the retina toward the center of the eye, forming a ridge between retina that has blood vessels in the back of the eye, and the retina that does not have blood vessels in the front of the eye. This difference in the blood vessels of the retina is because the premature baby has not had the time while in the womb to allow the blood vessels within the retina to grow all the way from the optic nerve in the back of the eye to the front of the eye.”
  • “Stage 3 ROP exists when these disturbing new blood vessels grow out from the ridge in the retina toward the center of the eye. If this blood vessel growth becomes severe and is accompanied by “plus” disease, the child may reach the point where treatment of the peripheral retina with laser (or rarely freezing) treatment is performed. “Plus” disease is defined as enlarged and twisting blood vessels in the back part of the eye.”
  • Plus Disease
    “Peripheral retinal treatment can reduce, but not eliminate, the chance of the ROP progressing to the potentially blinding stages 4 and 5. When stage 4 or 5 ROP is reached, the retina is detached and other therapies can be performed.”
  • Stage 4 ROP
    http://ropard.org/what_is.shtml

Treatment and Prevention:

• Laser Therapy
• Cryotherapy: “A treatment that uses cold as a destructive medium, usually liquid nitrogen
• Surgical Interventions
• Cautious delivery of oxygen
• Preventing hypoxia and/or toxicity
  • Use TCM’s, pulse oximeters and blood gases
• “Scleral buckling: Involves encircling the eyeball with a silicone band to try and reduce the pulling on the retina.” http://ropard.org/what_is.shtml
• “Vitrectomy: Removal of the gel-like substance called the vitreous that fills the back of the eye.” http://ropard.org/what_is.shtml
• “Removal of the lens as well is required during vitrectomy to try and eliminate as much pulling as possible from the retinal surface. Removal of the lens is performed if the retina is touching the back surface of the lens, which would make it impossible to enter the eye for vitreous surgery without damaging the retina.”

• Whitaker, Kent. Comprehensive Perinatal and Pediatric Respiratory Care, 3rd Ed. Delmar Thomson Learning, 2001. p303-306.
http://www.blindpreschool.ca/fact02.html
• http://med-aapos.bu.edu/aapos/dave1.html
• http://www.lowvision.org/retinopathy_of_prematurityxx.htm
• http://www.emedicine.com/ped/topic1998.htm
• http://www.checdocs.org/dr_retino.htm
• http://www.charles-retina.com/rop-faq.htm
• http://www.bostoncare.com/retinopathy_of_prematurity.htm
• http://www.nei.nih.gov/rop/
• http://www.nei.nih.gov/rop/photos.htm
• http://www.nei.nih.gov/neitrials/static/study40.htm
• http://www.nei.nih.gov/health/rop/index.htm#10
• http://www.uhseast.com/12061.cfm
• tsvbi.edu
• http://optom.tripod.com/retinopathy_of_prematurity.htm
• http://www.uic.edu/com/eye/LearningAboutVision/EyeFacts/RetinopathyOfPrematurity.htm
• http://www.ropard.org
• http://www.schepens.com/retinopathy_of_prematurity.htm
• http://www.nei.nih.gov/rop/images/ROP10-31-03.mpeg
• http://www.uic.edu/com/eye/LearningAboutVision/EyeFacts/RetinopathyOfPrematurity.htm
• http://www.visionchannel.net/retinopathy/