Examination of the premature infant

Ophthalmoscopic examination of the premature infant requires binocular indirect ophthalmoscopy, use of an eyelid speculum, and wide pupillary dilatation. Normal and pathologic features unique to the infant eye often are encountered. Familiarity with these features is essential for accurate diagnosis and prevention of unnecessary therapeutic intervention. Supplemental oxygen is the mainstay of supportive therapy for idiopathic respiratory distress syndrome, a common cause for morbidity in premature infants. Arterial oxygen monitoring is essential for survival and for prevention of retrolental fibroplasia, but precise arterial oxygen levels associated with development of retrolental fibroplasia have not been established.     

Refractive error in premature infants

PURPOSE: To determine the incidence and the degree of refractive error between the ages of 2 weeks and 6 months in premature infants without retinopathy of prematurity and to seek a correlation between refractive error and age at examination, birth weight, or gestational age. SUBJECTS AND METHODS: In this observational cross-sectional study, eye refraction in 390 premature infants, with no ocular pathology, was measured by cycloplegic retinoscopy at the age of 2 weeks to 6 months. A correlation was sought between refractive error and perinatal variables. RESULTS: Of the 390 infants reviewed, 347 (89%) had a refractive error and 43 (11%) were emmetropic in both eyes. Most of the infants were hyperopic (76.8%). Myopia was observed in only 11.9%. Astigmatism was found in 24.4% of the infants. The mean age at examination was 2.1 +/- 1 months; the mean birth weight was 1639 +/- 444 g, and the mean gestational age at birth was 32.2 +/- 2.4 weeks. The mean spherical equivalent of refraction was +1.56 +/- 1.82 diopters (D) in the right eye and +1.55 +/- 1.78 D in the left eye. Refractive error was positively correlated with age at examination ( R = 0.16, P = 0.001). The mean refractive error was +1.24 D in infants aged 1 month or less and reached +2.50 D at the age of 4 to 6 months. Refractive error was not correlated with birth weight or gestational age. CONCLUSIONS: The incidence of refractive error in premature infants without retinopathy of prematurity in the first 6 months of life may be as high as 89%. Most of these infants are hyperopic. Eye refraction is correlated with age at examination, but not with birth weight or gestational age.     

Ophthalmologic prevention in premature infants

Forty-four of the 262 pupils at the school for blind and visually handicapped children in Nuremberg, i.e., 17%, suffer from sequelae of retinopathy of prematurity (ROP); this condition is currently top of the list of causes of blindness. The risk factors involved were identified by analyzing 294 histories of premature children born between 1981 und 1984. In the case of 16 children, ophthalmoscopic criteria were taken from the 1984 international classification. The data of the children with ROP, at birth and at the time when ROP developed, were recorded on a prognosis card, in each case between the child's absolute age (abscissa) and birthweight in g (ordinate). In this way it was possible to read off the critical phase of retinal development for each newly examined child. This card facilitates monitoring, the provision of forensic evidence, the timing of ophthalmoscopy during critical phases of retinal development, and may also enable further relationships to be detected.     

Visual acuity in premature infants

PURPOSE: To measure grating visual acuity in premature infants and compare it with that in full-term infants. METHODS: The visual acuity of 73 premature and 73 full-term infants was tested at 6 months of age by the Teller Acuity Card procedure. All premature infants had undergone indirect funduscopy for the detection of retinopathy of prematurity (ROP). Seven infants had developed ROP. The mean gestational age of the premature infants was 33 +/- 1.4 weeks as compared with 39.9 +/- 0.9 weeks in the full-term infants. The mean birth weights of the 2 groups were 1,906 +/- 412 and 3,244 +/- 420 g, respectively. RESULTS: Impaired binocular visual acuity was found in 53.4% of the premature infants, but in only 11% of the full-term infants (p < 0.0001). Impaired monocular visual acuity was found in 13.7% of the premature infants as compared with 2.7% of the full-term infants. Within the premature infant group, monocular visual acuity was impaired in 42.9% of those with ROP and in 10.6% of those without ROP (p = 0.0497). Pathological refraction was found in 33.3% of the prematures without ROP and in 14.3% of the prematures with ROP. This difference was not statistically significant. Visual acuity of preterm infants was not different from full-term infants when examined at 6 months of postconceptual age. CONCLUSIONS: Both monocular and binocular visual acuities as measured by the Teller Acuity Cards are worse in premature infants than in full-term infants at the same chronological age. Poor visual acuity in premature infants can be attributed mainly to immaturity of the visual system.     

无早产儿视网膜病变的早产儿早期眼轴的初步研究

目的：探究无早产儿视网膜病变的早产儿早期眼轴长度(axial length,AL),分析AL与性别、胎龄、矫正胎龄、出生体质量及其它眼部生物学参数的相关性。

方法：选取2016-03/10于西北妇女儿童医院眼科筛查的无早产儿视网膜病变的早产儿400例800眼作为研究对象,对出生后4～6wk内首次检查所获得的AL等相关数据进行分析。

结果：本研究纳入早产儿400例800眼,右眼和左眼AL分别为16.11±0.58、16.13±0.53mm,差异无统计学意义(P>0.05),故以双眼AL的平均值作为该组受检者的AL即16.12±0.55mm。本研究中,不同性别早产儿AL差异无统计学意义(P>0.05)。Pearson相关分析表明,AL与胎龄、出生体质量、矫正胎龄、前房深度、玻璃体腔长度均呈正相关(r=0.427、0.401、0.635、0.691、0.878,均P<0.01),与晶状体厚度呈负相关(r=-0.153,P<0.01)。将上述因素纳入多元线性回归分析发现,AL与胎龄、前房深度、玻璃体腔长度具有显著相关性,得出回归方程Y=4.109+0.029X₁+0.481X₂+0.978X₃(Y=AL,X₁=胎龄,X₂=前房深度,X₃=玻璃体腔长度)。

结论：无早产儿视网膜病变的早产儿早期平均AL为16.12±0.55mm,且其与性别无关,与胎龄、出生体质量、矫正胎龄、前房深度、玻璃体腔长度均呈正相关,与晶状体厚度呈负相关。     

Retinopathy in premature infants. Present value of surveillance of premature and newborn infants at risk]

Systematic ophthalmologic screening of infants in a Neonatal Intensive Care Unit is time consuming and sometimes difficult. In this retrospective study of 1200 infants examined in the neonatal unit of Toulouse Regional Hospital from January 88 through December 89, we tried to summarize our findings and assess the value of systematic screening. We found 118 infants with abnormal examination: 58 preterms had retinopathy of prematurity (ROP) (5.16%) with 36 stage I, 15 stage II, 7 stage III (2 stage III+ had cryotherapy), no stage IV. Risk factors are discussed. 40 preretinal hemorrhages, all found in the first week of life. Only 2 of them persisted beyond the 2nd month (0.2%) and we found vascular anomalies that were cryotreated. 20 had various diseases. Diseases requiring early treatment were found in a general context with obvious need of ophthalmologic examination. Our study shows that 4 infants: 2 ROP III+ and 2 retinal hemorrhages or 0.4% of all infants obtained an effective benefit from this systematic screening. We confirmed the value of this screening: all infants in the neonatal care unit have at least one ophthalmologic exam, before they leave the hospital. Preterm less than 1600 g or less than 2000 g with initial resuscitation are checked during first and second month. Preterm less than 1200 g or less than 1600 g who had more than one month of oxygen therapy are checked every month until the 6th month.     

Corneal diameter in premature infants.

The size of the cornea is important in the diagnosis of primary infantile glaucoma. Reference values regarding eyes of premature infants are scarce. Such data are of special importance in areas such as the Middle East where infantile glaucoma is common and often evident already at birth. The authors have measured the horizontal corneal diameter of the eyes of 127 premature Saudi infants with a gestational age between 23 and 36 weeks and a birth weight ranging from 540 g to 4720 g. The corneal diameter ranged from 7.75 mm to 10 mm. The smallest diameter (7.75 mm) was found in an infant with a gestational age of 23 weeks and having a birth weight of 520 g. The largest diameter (10 mm) belonged to two infants with a gestational age of 34 and 35 weeks and a birth weight of 2250 g and 2240 g respectively. Corneal diameter was positively correlated (p < 0.001) with gestational age and birth weight. Graphs depicting the regression line of corneal diameter on gestational age and of corneal diameter on birth weight together with the 95% confidence limits for individual values are provided for reference.