Spontaneously resolving macular cyst in an infant.

The purpose of this study is to describe transient macular cysts in an infant and correlate their occurrence with normal development events. A newborn Caucasian girl presented with a protruding corneal mass in her left eye at birth. She underwent a complete ophthalmic examination. A keratinized staphylomatous malformation involving the entire cornea and precluding further visualization of the anterior and posterior segment was observed in the left eye. Spectral domain optical coherence tomography (SD-OCT) of the right eye performed when the child was approximately 6-week-old had revealed an unexpected finding of macular cysts involving the inner nuclear and outer retinal layers. Corneal transplant in the left eye was performed a month later. Ocular examination under anesthesia just prior to surgery revealed normal intraocular pressure, anterior segment and retina in the right eye. SD-OCT was normal in both eyes and showed complete resolution of the cysts in the right eye. The patient had not been on any medications at that time. Although clinical retinal examination might be unremarkable, SD-OCT may reveal cystic spaces in the macula. In the absence of conditions known to be associated with macular edema, transient macular cysts may arise due to a developmental incompetence of the blood-retinal barrier or may represent transient spaces created during normal migration of retinal cells. Further study is warranted to delineate the entity of transient macular cysts in infancy.

Introduction

Macular edema occurs in a broad spectrum of disorders that result in a localized collection of fluid due to breakdown of the blood retinal barrier. When it acquires a characteristic petalloid appearance due to the formation of cystic spaces, it is referred to as cystoid macular edema (CME). Non-CME macular cysts may also develop because of tissue loss secondary to disruption of retinal architecture in the macular region.[1] We report the detection of macular cysts by spectral domain optical coherence tomography (SD-OCT) in the normal eye of a systemically healthy infant. Spontaneous resolution was noted 6 weeks later, suggesting the possibility that this finding may be a benign developmental event.

Case Report

A newborn Caucasian girl presented with a protruding corneal mass in her left eye at birth. She was otherwise healthy and was born at term following a normal pregnancy and delivery. Family history was noncontributory.

We first examined the child when she was 2 months old. While preoperative visual response was appropriate for age in the right eye, vision was light perception in the left eye. Ophthalmic examination of the right eye was unremarkable. A keratinized staphylomatous malformation involving the entire cornea and precluding further visualization of the anterior and posterior segment was observed in the left eye. B-scan ultrasound showed a normal posterior segment. SD-OCT of the right eye done prior to arrival at our institution, when the child was approximately 6 weeks old, had revealed an unexpected finding of macular cysts involving the inner nuclear and outer retinal layers [Figure 1]. OCT could not be performed on the left eye due to the mass.

Figure 1

Spectral domain optical coherence tomography at 6 weeks age shows macular cysts in the inner nuclear and outer plexiform layers of the retina in the left eye. Vertical hyper-reflective columns traversing across and bridging the cavities can be seen

Corneal transplant was performed a month later. Ocular examination under anesthesia just prior to surgery revealed normal intraocular pressure, anterior segment and retina in the right eye. SD-OCT was normal and showed complete resolution of the cysts in the right eye [Figure 2]. She had not been on any medications at that time.

Figure 2

Repeat spectral domain optical coherence tomography performed at 10 weeks of age shows complete resolution of the macular cysts and normal macular morphology in the left eye

At the time of surgery, the child was found to have only peripheral remnants of iris in the left eye consistent with incomplete aniridia. The lens was anteriorly displaced. Histology of the mass and cornea confirmed a diagnosis of Peter's anomaly with an ectatic keratinized cornea. Molecular genetic testing of the paired box protein (PAX6) gene was negative. The eye was left with dense amblyopia such that occlusion of the otherwise normal right eye could not be sustained.

Discussion

Our patient with unilateral Peter's anomaly had a normal clinical retinal examination of the fellow eye, but SD-OCT incidentally revealed cystic spaces in the macula. OCT has been found to be a more sensitive tool than ophthalmoscopy in detecting macular pathology.[2]

Optimization of the hand-held SD-OCT for use in neonates and infants, has led to its wide-spread use in evaluating the macula in neonates.[3] Macular cysts involving the inner nuclear layer were detected by SD-OCT in 39% eyes of neonates undergoing routine screening for retinopathy of prematurity.[4] The authors speculated that the macular findings may be a vascular endothelial growth factor related phenomenon. Cabrera and coworkers evaluated the macular region of 39 healthy newborn infants with SD-OCT and reported subretinal cystic changes in the macula in 15% of infants.[5] They also reported spontaneous resolution by 1-4 months of age. The authors attributed the cystic changes to fluid accumulation. Intravenous fluorescein angiography was not performed in either of the afore-mentioned studies.

CME may develop in a newborn infant due to various conditions that disrupt the blood-retinal barrier. Our patient had no findings suggestive of any of the acquired causes of macular edema such as vascular occlusion, trauma, inflammation, or retinal dystrophy. The spontaneous resolution of the CME makes it more likely that transient accumulation of fluid in the macular region might have occurred due to a developmental incompetence of the blood-retinal barrier. The apical junctional complexes of the retinal pigment epithelial cells are initially leaky.[6] As the neural retina and choriocapillaris develop, there are progressive changes in the composition of the tight junctions, expression of cell adhesion proteins and distribution of membrane and cytoskeletal proteins, leading to the development of a competent outer blood-retinal barrier.[6] The cysts seen in our patient may also represent non-CME tissue spaces, again reflecting a transient developmental event. Several studies have shown that the macular region is not fully mature at birth. From birth until 15 months old, the fovea continues to deepen as a result of the migration of cells in the inner retina toward the periphery. There is also a central migration of cones and an elongation, maturation and increase in packing density of foveolar cones.[78] These structural evolutionary changes could perhaps also result in formation of transient spaces in the macula.

Although transient macular cystic changes in newborns have recently been reported,[45] our paper attempts for the first time to correlate their occurrence with normal developmental events.

Further study is needed to delineate the entity of transient macular cysts in the neonatal period and to determine their effect, if any, on visual development.