Periventricular leukomalacia with -16 DS high myopia in a 2½ months old infant: A rare case presentation.

Periventricular leukomalacia (PVL) is coagulation necrosis of white matter seen in preterm, low birth weight (LBW) infants and associated with a range of ocular manifestations. We report a case of 2½ months old (47 weeks gestational age) female infant with PVL associated with bilateral high myopia (-16 DS). On examination, child had difficulty in tracking objects and inferior field defect with preference for superior gaze. She was prescribed spectacles and visual stimulation exercises to preserve existing vision and prevent amblyopia. Periventricular leukomalacia can affect full-term infants although it is more common in preterm and LBW infants. All preterm, LBW infants, and those with positive neuroradiological findings must be assessed by an ophthalmologist as early as possible to detect the associated ocular manifestations.

Introduction

Periventricular leukomalacia (PVL) is ischemic injury of oligodendrocytes most commonly seen in premature babies between 29 and 34 weeks of gestational age due to the impaired cerebral autoregulation.[1] PVL is more prominent surrounding the lateral ventricles, descending corticospinal tract, visual and acoustic radiations. PVL affects the visual system maturation and is associated with defective visuospatial orientation, strabismus and optic disc anomalies.[2] PVL can also be seen in near-term (late preterm), as well as term infants. In a study done by Miller, 32% of full-term infants with congenital heart disease exhibited white matter injury.[3] We are presenting the case history of a 47 weeks old infant with PVL associated with bilateral high myopia of −16 DS. Though refractive errors are common in preterm babies, pathological myopia of −16 DS in a term infant with clear lens is uncommon. Early diagnosis and correction of high myopia are crucial as it decides the future visual status of the child.

Case Report

A 2½-month-old female infant (47 weeks gestational age) presented to pediatric ophthalmology department for evaluation of inward deviation of her right eye since birth. One month back she had high-grade fever, vomiting, lethargy, up rolling of eyes and two episodes of clonic seizures of both legs. Ophthalmic examination showed that the child could fix on target occasionally but was not maintaining fixation [Figure 1 and Video 1]. The child maintained an upward gaze suggesting an inferior visual field defect. Anterior segment examination was normal and ocular movements were full by dolls eye maneuver. A variable esotropia of <15 PD was seen in the right eye. Posterior segment examination showed tessellated fundus, dull foveal reflex, and small slightly pale discs with cup-disc ratio of 0.6 suggestive of pseudoglaucomatous cupping. The intraocular pressures were normal. There was no retinal nerve fiber layer thinning in the superior half. Retinoscopy revealed myopic refractive error of −16 DS in both eyes. Ultrasound B-scan revealed axial length of 24.75 mm in the right eye and 22.4 mm in the left eye, incomplete posterior vitreous detachment in both eyes with no evidence of posterior staphyloma.

Figure 1

Visual inattention to bright-colored target

Electroencephalogram showed generalized neuronal hyperexcitability; lumbar puncture revealed elevated neutrophil counts with reduced cerebrospinal fluid glucose level. Magnetic resonance imaging (MRI) of brain showed leptomeningeal enhancement and distension of subarachnoid space with widening of interhemispheric fissure suggestive of meningitis and hyperintense signal in the periventricular region with irregular ventricular margins suggestive of PVL [Figure 2].[4] She was treated with intravenous antibiotics, phenytoin, and subsequently improved. She had not attained neck control and social smile. Her parents are first-degree cousins. There is no similar history in her sibling.

Figure 2

Magnetic resonance imaging showing hyperintense signals inperiventricular white matter

The child was advised spectacles with slight undercorrection and advised to undergo visual stimulation exercises. At 2-month follow-up visit, the child was more visually responsive, demonstrated normal visual fixation and following [Video 2].

Discussion

PVL is caused by cerebral hypoperfusion and oxygen-free radical damage to the periventricular white matter.[1] 3%–4% of infants who weigh <1500 g and 4%–10% of those born before 33 weeks have PVL. Gestational cytomegalovirus infection can also produce PVL.[5] Bradycardia, polyhydramnios, abruptio placenta, and cardiopulmonary arrest are few inciting events for PVL [Table 1]. Full-term infants with congenital heart disease have a higher incidence of white-matter injury.[3] They can present to an ophthalmologist with delayed visual maturation, visual perceptual-cognitive problems, abnormal visual acuity, crowding, nystagmus, visual field defects, optic disk abnormalities, strabismus, and deficient visually guided eye movements.[2] Dutton et al. found more than 50% of patients with PVL had inferior field defects due to damage to the optic radiations in parietal lobe.[6] In PVL with adjacent cortex involvement, exotropia, horizontal tonic gaze deviation, and chaotic jerky nystagmus are noted while esotropia, tonic downgaze, and low-amplitude high-frequency nystagmus are more common in subcortical involvement.[2] Dorsal stream dysfunction includes inaccurate reaching, knocking over objects, difficulty in locating an object in crowded visual field, impaired simultaneous perception, and difficulty in seeing moving targets. Ventral stream dysfunction manifests with difficulties in orientation with unfamiliar places, recognizing faces.[7] If the damage to the optic nerve happens at a later stage of development, as in our case, it may show increased cupping with normal diameter and total atrophy of the disc occurs if the damage happens at an earlier stage.[5] This happens due to trans-synaptic degeneration of the axons. Preterm infant can be screened by transcranial ultrasound which may show hyperechoic cystic shadows in the periventricular region suggestive of PVL. MRI is the gold standard for diagnosis. The child could have developed PVL secondary to infectious etiology as there was no history of intrapartum or antenatal insult.

Table 1

Risk factors of periventricular leukomalacia

Although most of the babies are born hypermetropic, Mukherji et al. proposed that premature babies have increased incidence of myopia, particularly in female infants. Myopia in newborn has got no relationship with mode of delivery (normal vaginal delivery or cesarean section).[8] At birth, the visual acuity is 20/400 and reaches to 20/20 by 18–30 months. The average axial length of the neonatal eye is 16.8 mm, and it reaches 22 mm by 2 years of age. Thereafter, it continues to grow at a rate of 1.1–1.3 mm/year. Axial length is the largest contributor for determination of refractive error.[9] Zadnik et al. proposed that children of myopic parents tend to have an elongated globe predisposing to myopia later. In monkeys with monocularly fused lids, the vision deprived eyes tend to become longer and myopic. The cause of myopia here seems less likely to be genetic as her parents are emmetropic. We also could not relate PVL as the direct etiology of high myopia. However, such high myopia can be an association of various neurological disorders such as PVL. In our case, the ultimate aim of our treatment was to preserve as much vision as possible and prevent amblyopia by proper visual rehabilitation and spectacles. Although visual evoked potentials may help objectively to estimate the child's visual acuity, it was not done in our case.

Visual stimulation exercises are done with bright colored torch, mobile toys, and series of running lights. They help in developing fixation, localization, tracking, establishing eye contact, gaze shift, and eye–hand coordination. Computer-based programs with passive checkerboard stimulation, oddball stimulus design with interesting auditory feedback could be considered as a potential intervention option to improve the vision of children with neurological disorders.[10]

Conclusion

Decrease in visual acuity may affect the physical and intellectual capacity of children. Visual function is an important parameter that directly affects the learning process. Therefore, babies born with positive neuroradiologic findings as well as lower gestational age and birth weight must be assessed by an ophthalmologist as early as possible. Optimal educational and rehabilitation strategies should be developed to meet the needs of visually impaired children.

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Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.