Introduction:
Retinopathy of prematurity (ROP) is globally the most common cause of childhood visual loss. Roughly 32,300 infants worldwide get diagnosed with irreversible vision damage due to ROP each year, with roughly 20,000 becoming blind or severely visually handicapped. Despite substantial breakthroughs in neonatal care, the global number of neonates with ROP has risen as the survival rate of preterm infants has grown. While great progress has been made in understanding the causes and management of ROP over the last few decades, its prevalence and associated blindness remain an issue. To avoid acquired childhood blindness resulting from ROP, it is critical to study its epidemiology and devise effective treatment approaches.
What Is Retinopathy of Prematurity?
Since its discovery in 1942, ROP has been regarded as the most common cause of childhood blindness. Historically, there have been global tri-phasic outbreaks of ROP and ROP-induced blindness. Retinopathy of prematurity is a visual disorder that affects some newborns born prematurely (before 31 weeks). ROP causes aberrant blood vessels to develop in a baby's retina. The retina is a layer of tissue at the back of the eye that turns light into electrical signals transmitted to the brain. The brain interprets this information and forms the images that comprise vision.
What Is the Pathophysiology of Retinopathy of Prematurity?
ROP arises in premature newborns that give birth before the retinal vessels have completed their normal development.
ROP comprises two phases:
-
Oxygen stress can cause delayed retinal vascular development and harm newly formed capillaries. Additionally, abnormal neovascularization can occur in the vitreous rather than the retina.
-
In premature newborns, even room air creates a hyperoxic environment as compared to the intrauterine environment, and oxygen supplementation in cases of respiratory distress exacerbates this hyperoxia.
-
In this phase, hyperoxia inhibits retinal vessel growth, causing partial regression of existing vessels.
-
The second step involves hypoxia-induced pathologic vasoproliferative. Incomplete vascularization leads the retina to become hypoxic, resulting in the release of numerous angiogenic factors like VEGF (vascular endothelial growth factor) and erythropoietin, and then to neovascularization, which leads to intraocular fibrosis and retinal detachment.
How Common Is this Condition?
About 90 percent of these infants have a moderate type of ROP that does not require treatment. There are around 1,100 to 1,500 people who suffer from a severe type that requires treatment. ROP causes legal blindness in 400 to 600 newborns per year.
What Are the Signs and Symptoms of Retinopathy of Prematurity?
There are generally no clear indications or symptoms to notice in a newborn. To determine whether the baby has ROP, an ophthalmologist must closely examine the eyes (including the development of blood vessels in the retinas).
What Are the Complications of Retinopathy of Prematurity?
Untreated, serious instances of retinopathy of prematurity might result in retinal detachment. This means the baby's retina separates from the supporting tissues around it. Retinal detachment can result in significant vision loss or blindness.
What Are the Treatment Options?
The current treatment indications are based on the ETROP study of type 1 ROP, classified as zone 1, any stage of ROP with plus disease; zone 1, stage 3 ROP without plus disease; and zone 2, stage 2 or 3 ROP with plus disease. The CRYO-ROP research conducted in 1986 identified cryotherapy of the avascular retina as the first surgical option for ROP that was acknowledged as safe and effective. This minimized negative outcomes in the eye with threshold ROP.
1. Laser Photocoagulation:
-
The current standard treatment for serious ROP is laser ablation of the peripheral avascular retina. Since the ETROP trial study demonstrated a reduction in unfavorable structural outcomes following previous therapy for high-risk pre-threshold ROP, laser therapy has been regarded as the gold standard for reducing vascular activity and, as a result, reducing the need for surgical treatment for fibrovascular tractional retinal detachment.
-
Laser treatment is now considered quickly for type 1 ROP, whereas careful monitoring is indicated for type 2 ROP.
2. Anti-VEGF Therapies:
-
Intravitreal anti-VEGF therapy is a relatively new treatment option for ROP. Experimental evidence suggests that regulating the VEGF signaling pathway can inhibit pre-retinal neovascularization and facilitate developmental intra-retinal angiogenesis.
-
Retinal ablation includes laser photocoagulation and cryotherapy, which is aimed at eliminating the peripheral avascular retina, and intravitreal anti-VEGF injection encourages the restoration of VEGF signaling to normal levels locally in the retina, which is an appropriate treatment.
3. Cryotherapy:
-
Conventional treatment aims to avoid fibrovascular retinal detachment by suppressing abnormal intravitreal angiogenesis. Threshold ROP was defined as 5 consecutive or 8 total clock hours of stage 3 ROP in zone 1 or zone 2 plus illness.
-
The avascular retinal of threshold ROP was treated similarly using argon and diode lasers. Lasers outperformed cryotherapy because they were easier to carry, well-tolerated, and less harmful.
Conclusion:
Neonatal care has improved dramatically during the last few decades. Nevertheless, ROP remains the biggest cause of pediatric visual impairment worldwide. Understanding the diversity of ROP outbreaks worldwide is critical to reducing this significant global burden. The essential element of ROP prognosis is to prevent it from progressing to an advanced stage and to make it more efficient, the ROP categorization system was developed and improved. Anti-VEGF drugs, except one (Ranibizumab) licensed in Europe, are still used off-label, necessitating the establishment of their safety and efficacy, as well as long-term study results, as with other treatments.
