Introduction

Primary Hyperplastic Persistent Vitreous (PHPV) is a congenital disease resulting from ocular dysplasia during the embryonic development of the primary vitreous. Its most common complications include tractional retinal detachment, secondary glaucoma, strabismus, and amblyopia [1]. Here, we present the first case of unilateral anterior PHPV posing as perceptual exotropia.

Case presentation

A four-year-old Chinese boy was admitted to our department with a major complaint of exotropia for one year. The patient previously underwent strabismus surgery to correct the issue without any additional intervention. He was a full-term baby, and his mother was 34-year-old at the time of birth. There is no family history of similar complaints. His physical and mental developments are within normal ranges, with a best-corrected visual acuity of 20/25 in the right eye and 20/125 in the left eye. The right eye examination was unremarkable, while the left eye showed a 30°exotropia with normal eye movement. The slit-lamp examination revealed a normal anterior segment and a transparent lens, while the fundus examination revealed a fibrous vascular membrane originating from the optic disc and extending forward to the rear segment of the lens (Figure 1). An A-scan indicated axial lengths of 22.3mm and 22.2mm in the right and left eyes, respectively. A B-scan, performed for posterior segment assessment, revealed a funnel-shaped echo band in the vitreous cavity extending to the anterior segment of the vitreous and adhering to the lower part of the posterior capsule of the lens. It displayed ocular motion-induced movements without posterior shift (Figure 2). The continuation of the cord-like blood flow signal was detected by Color Doppler ultrasonography, which also indicated the presence of the central retinal artery within the lesion (Figure 3). A diagnosis of PHPV with perceptual exotropia in the left eye was made based on these clinical findings and investigations. Promptly after admission, a 23G minimally invasive vitrectomy was performed under general anesthesia. A vitreous cutting head was used to section the preoptic disc fibrovascular column to release it from the posterior part of the lens. Fibrovascular membrane adherent to the optic papilla was electrocoagulated to avoid active hemorrhage, and laser photocoagulation was used to seal the adjacent retina. The one-week (Figure 4) and two months (Figure 5) post-surgery follow-up visits showed no postoperative complications.

Figure 1: Fundus examination revealing the fibrous vascular membrane from the optic disc extending forward to the rear of the lens.

Figure 2: B-scan showing a funnel-shaped echo band in the vitreous cavity extending to the anterior segment of the vitreous and adhering to the lower part of the posterior capsule of the lens.