Retinopathy of prematurity

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

Normal retinal vascularization begins on the 4th month of the gestational period and ends by the 9th month.

[1], [2], [3], [4], [5],

Symptoms of retinopathy of prematurity

Retinopathy of prematurity occurs either as a response to prolonged exposure to large concentrations of oxygen used in nursing preterm infants, or as a result of deep prematurity at low body weight. Various forms of neovascularization are observed. Pathological preretinal neoplasms can regress if retinal vessels develop normally in the retina, and may progress, leading to traction, exudative or rheumatogenic retinal detachment. The disease usually begins in the first 3-6 weeks of life, but not later than the 10th week. Cicatricial stages fully develop by the 3rd-5th month.

Active retinopathy of prematurity

Active retinopathy of prematurity is determined by: localization, size, stage, the "plus-illness"

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

• Zone 1 is limited to an imaginary ring whose radius is two distances from the optic nerve to the macula;
• zone 2 extends concentrically from the edge of zone 1 to the nasal side of the og serrata and temporal to the equator;
• zone 3 consists of a residual temporal region in the form of a crescent anterior to zone 2.

Dimensions of the pathological retina are determined clockwise, according to the dial clock.

Stages of

• Stage 1 (the demarcation line). The first pathognomonic sign of retinopathy of prematurity is the appearance of a thin, uneven, grayish-white line, parallel to the sera of serrata, dividing the avascular underdeveloped peripheral retina from the vascularized posterior segment. This line predominates more temporally at the periphery, from it abnormal vessels can depart;
• Stage 2 (shaft). If the retinopathy of prematurity progresses, the demarcation line passes into the prominence shaft, represented by a mesenchymal shunt connecting the arterioles and veins. Vessels approach the shaft, behind it can be identified small isolated areas of neovascularization;
• Stage 3 (shaft with extrorefinal fibrovascular proliferation). With the progression of the disease the shaft acquires a pink shade due to fibrovascular proliferation, which grows over the surface of the retina and into the vitreous. It is accompanied by the expansion and tortuosity of the retina vessels posterior to the equator. Often there are hemorrhages of the retina, sometimes in the vitreous. This stage is mainly characteristic for the 35th week of the general gestational age;
• Stage 4 (subtotal retinal detachment) is due to the progression of fibrovascular proliferation. The detachment starts from the extreme periphery and spreads more neutrally. Typical for the 10th week of the newborn;
• stage 5 - total detachment of the retina.

Although the clinical symptoms of retinopathy of preterm develop within a few weeks. Occasionally the disease progresses from stage 1 to stage 4 in a few days. In 80% of patients with retinopathy of prematurity, spontaneous regression of the disease takes place, sometimes without residual phenomena on the retina. Spontaneous regression is possible even in patients with incomplete retinal detachment.

Other manifestations of retinopathy of prematurity

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

• Rigidity of the pupil associated with a significant vascularization of the iris.
• Development of opacity of the vitreous.
• Opacification in the vitreous body.
• Increase in the number of hemorrhages of the retina and vitreous.

With these changes, a plus sign is placed next to the stage of the disease.

"Threshold" disease is determined by extraretinal neovascularization of 5 consecutive or 8 total inconsistent meridians (stage 3) in zones I or 2, combined with "plus" disease and is an indicator for the initiation of treatment.

[6], [7], [8], [9]

Cicatricial retinopathy of prematurity

Approximately in 20% of patients the active retinopathy of prematurity passes into the cicatrical stage, which can manifest itself in varying degrees - from insignificant to severe. In general, the more pronounced the proliferative disease at the time of involution, the worse the consequences of scarring complications.

• Stage 1. Myopia associated with delicate peripheral pigmentation of the retina and opacities at the base of the vitreous.
• Stage 2. Vitreoretinal fibrosis from the temporal side with a strain of the macula, which can lead to pseudo-exotropy due to the expansion of the kappa angle.
• Stage 3. More pronounced peripheral fibrosis with retinal folds.
• Stage 4. Retrolental fibrovascular tissue in the form of a half-ring with incomplete retinal detachment.
• Stage 5. Retrolental fibrovascular tissue in the form of a ring with total retinal detachment is a phenomenon previously known as "retrolental fibroplasia".

[10], [11], [12], [13], [14], [15], [16], [17]

Diagnosis of retinopathy of prematurity

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

Visual acuity is significantly reduced (before light sensation), there is no electroretinogram in the presence of detachment. The diagnosis is established based on the history, results of ophthalmoscopy, ultrasound examination, electroretinography and registration of visual evoked potentials.

Differential diagnosis, depending on the clinical symptoms, is carried out with retinoblastoma, newborn hemorrhages, intracranial hypertension, congenital anomalies of retinal development, especially familial exudative vitreoretinopathy (Criswick-Skepens disease), characterized by impaired vascularization of the retina, fibrotic changes in the vitreous and frequent retinal detachment. The gene responsible for the development of familial exudative vitreoretinopathy is localized in the 11th chromosome at site ql3-23.

[18], [19], [20], [21], [22], [23]

Treatment of retinopathy of prematurity

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

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