Retinopathy of prematurity

Retinopathy of prematurity, or vasoproliferative retinopathy (formerly called retrolental fibroplasia) is a disease of the retina of very premature babies, in whom the vascular network (vascularization) of the retina is not fully developed at the time of birth.

Normal retinal vascularization begins in the 4th month of gestation and ends by the 9th month.

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Symptoms of Retinopathy of Prematurity

Retinopathy of prematurity occurs either as a response to prolonged exposure to high concentrations of oxygen used in nursing premature infants or as a result of extreme prematurity with low body weight. Various forms of neovascularization are observed. Pathological preretinal neovascularization may regress if normal retinal vascular development occurs in the retina, or it may progress, leading to tractions, exudative or rhegmatogenous retinal detachment. The disease usually begins in the first 3-6 weeks of life, but not later than the 10th week. Cicatricial stages are fully developed by the 3rd-5th month.

Active retinopathy of prematurity

Active retinopathy of prematurity is determined by: location, size, stage, and the presence of "plus disease"

Localization is determined by three zones, the center of which is the optic nerve disc:

• zone 1 is limited by an imaginary ring, the radius of which is two distances from the optic nerve head to the macula;
• zone 2 extends concentrically from the edge of zone 1 to the nasal side of the serrata orb and temporally to the equator;
• Zone 3 consists of a residual crescent-shaped temporal region anterior to zone 2.

The dimensions of the pathological retina are determined clockwise, corresponding to the hours on the dial.

Stages

• stage 1 (demarcation line). The first pathognomonic sign of retinopathy of prematurity is the appearance of a thin, uneven, grayish-white line parallel to the serrata ora, separating the avascular, underdeveloped peripheral retina from the vascularized posterior segment. This line protrudes more temporally toward the periphery, and abnormal vessels may extend from it;
• stage 2 (val). If retinopathy of prematurity progresses, the demarcation line passes into the prominence val, represented by a mesenchymal shunt connecting arterioles and veins. Vessels approach the val, behind which small isolated areas of neovascularization can be determined;
• stage 3 (shaft with extraretinal fibrovascular proliferation). As the disease progresses, the shaft acquires a pink tint due to fibrovascular proliferation, which grows along the surface of the retina and into the vitreous body. It is accompanied by dilation and tortuosity of the retinal vessels posterior to the equator. Retinal hemorrhages often occur, sometimes into the vitreous body. This stage is mainly characteristic of the 35th week of general gestational age;
• stage 4 (subtotal retinal detachment) is caused by the progression of fibrovascular proliferation. The detachment begins from the extreme periphery and spreads more neutrally. Typical for the 10th week of the newborn;
• stage 5 - total retinal detachment.

Although clinical symptoms of retinopathy of prematurity develop over several weeks, the disease rarely progresses from stage 1 to stage 4 in a few days. Spontaneous regression of the disease occurs in 80% of patients with retinopathy of prematurity, sometimes without residual effects on the retina. Spontaneous regression is possible even in patients with incomplete retinal detachment.

Other manifestations of retinopathy of prematurity

"Plus" disease indicates a tendency to progress and is characterized by the following:

• Pupil rigidity associated with significant vascularization of the iris.
• Development of vitreous opacity.
• Opacities in the vitreous body.
• An increase in the number of retinal and vitreous hemorrhages.

If these changes are present, a plus sign is placed next to the stage of the disease.

“Threshold” disease is defined by extraretinal neovascularization of 5 consecutive or 8 total non-consecutive meridians (stage 3) in zones I or 2, combined with “plus” disease and is an indicator for the start of treatment.

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Cicatricial retinopathy of prematurity

In approximately 20% of patients, active retinopathy of prematurity progresses to the cicatricial stage, which can manifest itself to varying degrees - from insignificant to pronounced. Basically, the more pronounced the proliferative disease is at the time of involution, the worse the consequences of cicatricial complications.

• Stage 1: Myopia associated with fine peripheral retinal pigmentation and opacities at the base of the vitreous.
• Stage 2: Vitreoretinal fibrosis on the temporal side with macular tension, which may lead to pseudoexotropia due to widening of the kappa angle.
• Stage 3: More pronounced peripheral fibrosis with retinal folds.
• Stage 4. Retrolental fibrovascular tissue in the form of a semicircle with incomplete retinal detachment.
• Stage 5: Retrolental fibrovascular tissue in a ring with total retinal detachment - a phenomenon previously known as "retrolental fibroplasia".

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Diagnosis of retinopathy of prematurity

Changes in the fundus of the eye in this pathology begin with vascular proliferation, then fibrovascular membranes are formed, hemorrhages, exudates, and retinal detachment appear. In the early stages of retinopathy of prematurity, spontaneous regression of the disease and cessation of the process at any stage are possible.

Visual acuity is significantly reduced (to light perception), electroretinogram is absent in the presence of detachment. The diagnosis is established based on anamnesis data, ophthalmoscopy results, ultrasound examination, electroretinography and registration of visual evoked potentials.

Differential diagnostics depending on clinical symptoms include retinoblastoma, neonatal hemorrhages, intracranial hypertension, congenital anomalies of retinal development, especially familial exudative vitreoretinopathy (Criswick-Schapens disease), characterized by impaired retinal vascularization, fibrous changes in the vitreous body, and frequent development of retinal detachment. The gene responsible for the development of familial exudative vitreoretinopathy is localized in chromosome 11 in the ql3-23 region.

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Treatment of retinopathy of prematurity

Treatment of retinopathy of prematurity in the early stages is usually not required. In later stages, antioxidants, angioprotectors, and corticosteroids are used depending on the clinical manifestations. Treatment for active retinal neovascularization includes local cryotherapy or laser and photocoagulation. In eyes with retinal detachment, the effect of cryotherapy, laser and photocoagulation is short-term. The choice of surgical treatment for retinal detachment depends on the type and extent of detachment (vitrectomy or its combination with sclerotoxic surgeries).

1. Ablation of avascular underdeveloped retina by cryo- or laser coagulation is recommended for "threshold" retinopathy of prematurity. The result is favorable in 85% of cases; in the rest, despite treatment, retinal detachment develops.
2. Vitreoretinal surgery for tractional retinal detachment is often ineffective.