Retinopathy of prematurity (ROP) is a condition of the eye occurring in premature infants (less than 31 weeks of gestation) caused by abnormal development of blood vessels in the retina that has been exposed to high-concentration oxygen therapy. Babies who are born with low birth weight are particularly more susceptible to developing this.
ROP is a potentially blinding condition that needs to be assessed and treated as in severe cases it can cause the retina to pull away and detach due to progressively proliferating vessels.
⦁ Low weight at birth (less than 1.5 kg or 1500 grams)
⦁ Gestation age less than 31 weeks
⦁ Exposure to oxygen concentration
⦁ Blood transfusion
⦁ Respiratory distress or other breathing difficulties
The retina is the innermost layer of the eye that receives light and converts it into signals (visual impulses) that are sent to the brain via the optic nerve. When a baby is born premature, the temporal (outer portion) of the retina is not developed because its development is completed one month after birth. When these babies are exposed to oxygen, their newly developing capillaries get obliterated. When oxygen is stopped, there is compensatory development of abnormal capillaries.
All the babies who are born premature (less than 31 weeks of gestation) with low birth weight must be screened for ROP. Babies should be assessed right after their discharge from NICU or within 4-6 weeks after birth. Pediatricians, NICU (neonatal intensive care unit) staff, and Obstetricians must be guided about the importance of screening to prevent this blinding condition.
Ophthalmologists who are skilled in examining infant eyes make the diagnosis of ROP after carefully looking retina through an indirect ophthalmoscope. The eye is dilated by instilling dilating drops and then the retina is seen carefully to assess the stage of retinopathy of prematurity. Diagnosis is very important as many infants have a mild disease that can be managed easily in the early stages.
Clinical features of ROP are classified according to the location of disease in the eye(ZONE), STAGES of ROP, and appearance of retinal vessels (PLUS DISEASE)
ZONE OF INVOLVEMENT OF ROP
ZONE-1: Any ROP in zone-1 is very serious so it needs treatment if has plus disease with it, or if ROP is in stage-3 or onwards. otherwise, it needs only regular observation
ZONE-2: Stage-2 or stage-3 with plus disease in zone-2 requires treatment. Stage-3 in zone-2 without plus disease needs regular observation.
ZONE-3: It is a safer zone so it requires observation only
STAGE-1: only a demarcation line between proliferating portion and the non-proliferating portion of the retina
STAGE-2: the demarcation line has elevated and new blood vessels start entering into it
STAGE-3:Proliferation of blood vessels outside the retina
STAGE-4: Partial detachment of the retina
STAGE-5: When there is total separation of the retina called retinal detachment
PLUS DISEASE: When ROP is characterized by dilation and tortuosity of vessels, vitreous haze, and failure of the pupil to dilate.
⦁ LASER ABLATION of the premature portion of the retina is done. It is the most common method of treatment around the world and it is being done for many years.
⦁ INJECTION OF AVASTIN (Anti-VEGF) causes a decrease in the formation of new abnormal vessels. It is a newer treatment and is showing a good response. Further research is in the process of looking for safety, optimal dosage, and the response to treatment
⦁ SURGICAL PROCEDURES LIKE VITERECTOMY OR SCLARAL BUCKLING is done if ROP continues be worsen or it has pulled the retina called retinal detachment.
⦁ Follow-up after discharge from the hospital is necessary since ROP may not be resolved before discharge. timing of regular follow-ups is very important because any delay in assessment and treatment may cause vision loss. There may be other vision problems associated with it like a squint,
visual impairment, and amblyopia ( lazy eye), so long-term observation of the eye by an ophthalmologist is important.