Diagnostic criteria for retinopathy of prematurity.
According to the pathogenesis of retinopathy of prematurity, it is clinically classified into acute active phase, degenerative phase and scarring phase.
Acutely active phase.
Staging and partitioning were performed according to the international classification of ROP (ICROP) combined with the screening criteria of the University of Toronto Children’s Hospital in Canada.
1. Staging.
Stage 0: There is no ROP lesion of any kind (nor is there a dividing line for stage 1), but the retina is not completely vascularized.
Stage Ⅰ: A white flat thin demarcation line appeared between the vascularized and non-vascularized areas in the posterior pole of the retina.
Stage II: The white demarcation line further widens and increases in height, forming a crest-like elevation above the retinal surface.
Stage III: The crest-like bulge develops further with new blood vessels growing into the crest and vitreous fibers proliferating.
Stage IV: partial retinal detachment, stage IVa peripheral retinal detachment without macular involvement, stage IVb retinal detachment progressing to the center and involving the macula.
Stage V: total retinal detachment in the shape of a funnel.
2.Zone.
Zone Ⅰ: centered on the optic disc, within the area of 2 times the distance from the optic disc to the central macular recess.
Zone Ⅱ: centered on the optic disc, the distance from the optic disc to the nasal serrated edge is the radius, excluding zone Ⅰ.
Zone Ⅲ: the area of the crescent beyond zone Ⅱ on the temporal side, which is the site of frequent retinopathy of prematurity.
3.Special lesions ;
(1) Additional lesion (plus): the retinal vessels in the posterior pole appear angry and distorted, or the anterior iris vessels are highly dilated. Additional lesions are an indication of active ROP, and once they appear, it means poor prognosis.
(2) Threshold lesion: ROP stage III, in zone I or II, with neovascularization occupying 5 o’clock ranges consecutively or lesions discontinuous but involving 8 o’clock ranges with PLUS. this stage is the key to early treatment.
(3) Pre-threshold lesions ;
a. Pre-threshold lesion type 1.
i.Any stage lesion of zone I with PLUS lesion;
ii. Stage III lesions in zone I without additional lesions;
iii. Stage II or III lesions in zone II with additional lesions.
b. Pre-threshold lesion type 2.
i. Stage I or II lesions in zone I without additional lesions;
ii. Stage III lesions in zone II without additional lesions.
(4) Rush lesion: ROP lesions are confined to zone I with flat neovascularization. This stage of lesion development is rapid and should be alerted.
Degenerative phase.
Most children enter the degenerative phase as ROP development stops with age. This phase is characterized by the gradual regression of the crest and the growth of normal retinal capillaries towards the avascular area of the retina, leaving no sequelae. However, 20% to 25% of children still progress into the scar stage.
Scar stage.
The irreversible changes left behind when the active lesion subsides become the scar stage.
Grade 1: No significant changes in the posterior pole of the fundus, mild scarring in the periphery (pigmentation, choroidal atrophy), and mostly normal vision.
Degree 2: retinal vessels traction to temporal side, macula deviated to temporal side, pigmentation, opaque white tissue mass visible in the periphery. If the macula is not involved, the vision is good. If the macula is involved, there will be different degrees of visual impairment.
Degree 3: Retinal folds are formed, adhered to the lesioned vitreous membrane and wrapped by blood vessels, and connected to the white tissue mass toward the periphery, and vision is generally below 0.1.
Degree 4: A white cloudy substance occupies part of the pupil area within the vitreous membrane of the posterior part of the lens.
Degree 5: Fibrous tissue proliferation behind the lens, forming corneal clouding, complicated by cataract, often with eye atrophy and vision loss.
Differential diagnosis.
1. Permanent primitive vitreous hyperplasia (PHPV): due to incomplete degeneration of vitreous vessels, resulting in retinal hyperplasia and crepitations. The child has no history of prematurity, mostly monocular onset, no ROP-like vascular abnormalities in the fundus, and the residual primitive proliferative vitreous behind the crystal is grayish white.
2. Hereditary diseases.
(1) Familial exudative vitreoretinopathy (FEVR): fundus changes are similar to ROP, the disease is autosomal dominant, there is a family history, the lesion is a chronic process, there is no history of prematurity or oxygen absorption.
(2) pigmentary incontinence: X-chromosome chain dominant disorder, male children do not survive and those who do are female. The onset of the disease is bilateral, with fundus changes similar to those of ROP, but the extent of the lesions is asymmetrical, and 35% are accompanied by other ocular abnormalities. Other changes include rash, dental abnormalities and neurological abnormalities such as epilepsy, delayed mental development and spastic paralysis, but there is no history of premature birth.
(3) Norrie’s disease: It is an X-chromosome linked recessive disorder in which the mother is the carrier and the male child is affected. 1/3 of the patients have congenital blindness, deafness and mental abnormalities. The disease develops in both eyes and manifests as tractional retinal detachment and peripheral fibrous membrane formation. The disease appears shortly after birth and progresses very rapidly.
3, inflammatory lesions: peripheral uveitis, Toxoplasma gondii infection and other lesions, in addition to peripheral retinal exudate, proliferation, patients do not have a clear history of premature birth, history of oxygen, the lesions develop quickly, usually a few days after the onset of ocular inflammatory manifestations, such as anterior chamber pus, vitreous turbidity, ciliary congestion and eye pain.
4, tumor: retinoblastoma is common, and the white pupil sign also appears in the late stage. However, most patients do not have a history of prematurity and have a family history. The mass and calcified spots are visible on ultrasound and CT.
5, congenital cataract: the lesion site of children with this disease is in the lens, and the ROP is posterior lens clouding.