When a child is born with a drooping upper eyelid, parents often first notice the appearance: one eye seems smaller, the face looks asymmetric in photos, or the child raises the eyebrows or tilts the head to see more clearly. For ophthalmologists, however, congenital eyelid drooping is not only a cosmetic issue. If the upper eyelid covers the pupil, less light reaches the eye, and visual development may be affected during a critical period of childhood.
One relatively uncommon form of congenital ptosis is Marcus Gunn jaw-winking syndrome, or MGJWS. Children with MGJWS may show upper eyelid drooping at rest, but the eyelid can lift involuntarily during jaw-related movements such as opening the mouth, chewing, swallowing, or shifting the jaw. The condition is estimated to occur in about 2%–12% of patients with congenital ptosis and is thought to arise from abnormal neural connections between the muscles involved in chewing and eyelid movement.
Although MGJWS has long been recognized clinically, its effects on visual development have often been discussed under the broader category of congenital ptosis. Yet clinicians have observed an important difference. Children with simple congenital ptosis may compensate for the blocked visual axis by lifting the eyebrows or tilting the head backward. Children with MGJWS do not always develop these sustained compensatory behaviors. A study published in Eye Discovery , titled " Visual Development in Children With Marcus Gunn Jaw-Winking Syndrome and Congenital Blepharoptosis: Early Intervention Considerations ," asked whether MGJWS affects visual development differently from simple congenital blepharoptosis.
Researchers from Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, and collaborating institutions conducted a retrospective cohort study of children aged 3–12 years who were diagnosed with unilateral congenital ptosis and underwent surgery between January 1, 2018, and February 28, 2023. The study included 29 children with MGJWS and 57 children with simple congenital blepharoptosis. The two groups were closely matched for age, sex, and ptosis severity, allowing the researchers to compare visual outcomes with improved baseline comparability. The team collected data on ptosis severity, marginal reflex distance 1, compensatory visual behaviors, refractive status, and best-corrected visual acuity.
The study first found that pupil obstruction was associated with poorer visual development, and that this effect appeared more pronounced in children with MGJWS. Among children with severe ptosis, the interocular difference in logMAR best-corrected visual acuity was greater in the MGJWS group than in the simple blepharoptosis group (0.4005 ± 0.3156 vs. 0.2023 ± 0.2061, P < 0.05). This suggests that, even at a similar level of ptosis severity, visual development may be more asymmetric in children with MGJWS.
A similar pattern emerged when children were grouped according to whether the pupil was obstructed. In the MGJWS group, children with pupil obstruction had a much larger difference in vision between the affected and fellow eyes than those without obstruction (0.3566 ± 0.3026 vs. 0.0340 ± 0.1083, P < 0.01). In the simple blepharoptosis group, pupil obstruction was also associated with a greater interocular difference (0.1910 ± 0.1895 vs. 0.1004 ± 0.0838, P < 0.05). When pupil obstruction was present in both groups, children with MGJWS had poorer visual acuity in the affected eye and a greater interocular visual acuity difference than children with simple blepharoptosis. These findings suggest that static pupil obstruction alone may not fully explain the greater visual differences observed in children with MGJWS.
The researchers then focused on compensatory visual behaviors. Some children with simple congenital ptosis raise the eyebrows or tilt the head to expose the pupil, whereas sustained compensatory behaviors were less common in children with MGJWS. Although jaw movement may briefly elevate the eyelid, this intermittent opening may not provide the same visual exposure as sustained compensation. In a comparison between 24 children with MGJWS who lacked compensatory behaviors and 33 children with pupil-obscuring simple blepharoptosis, the MGJWS group had poorer vision in the affected eye and a larger interocular difference in logMAR best-corrected visual acuity (0.3502 ± 0.2076 vs. 0.1910 ± 0.1895, P < 0.05). The result suggests that the absence of sustained behaviors such as eyebrow lifting or head tilting may make children with MGJWS more vulnerable to visual deprivation caused by eyelid obstruction.
The study also found differences in refractive development. Among children aged 3–6 years, both the affected and fellow eyes in the MGJWS group showed lower hyperopic reserve than those in the simple blepharoptosis group. Spherical equivalent values were 0.1375 ± 1.482 vs. 1.415 ± 1.568 in the affected eye and 0.35 ± 0.6203 vs. 1.089 ± 1.135 in the fellow eye, with both differences reaching statistical significance (P < 0.05). The interocular difference in spherical equivalent was also larger in the MGJWS group (1.238 ± 0.7693 vs. 0.6652 ± 0.7104, P < 0.05). Reduced hyperopic reserve does not mean that a child has already developed myopia, but during early refractive development it may indicate less remaining "buffer" before the eye shifts toward emmetropia or myopia. For children with MGJWS, the findings suggest that clinicians may need to monitor not only vision in the affected eye, but also refractive development in both eyes.
Professor Jin Li from the Department of Ophthalmology at Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, said: "MGJWS has often been discussed within the broad framework of congenital blepharoptosis, but in clinical practice we noticed that these children do not always compensate for visual axis obstruction in the same way as children with simple ptosis. Our study aims to remind clinicians that MGJWS may not be merely an abnormal eyelid position. Its abnormal neural synkinesis and lack of sustained visual compensation may jointly affect visual development. The current findings support earlier assessment of visual development and surgical timing, but they do not mean that all children should receive the same intervention. Pupil obstruction, visual acuity, refractive status, and individual developmental features should all be considered."
The clinical value of the study lies in separating MGJWS more clearly from the broader category of congenital ptosis. The findings suggest that visual risk in children with MGJWS may depend not only on how much the eyelid covers the pupil at rest, but also on whether the child has stable compensatory visual behaviors. Brief eyelid opening during jaw-winking should not be assumed to provide the same visual benefit as sustained eyebrow lifting or head tilting. For children aged 3–6 years, when visual and refractive development remain highly active, earlier ophthalmic assessment, refractive monitoring, and individualized discussion of surgical timing may be especially important.
Article information:
Dai Su, Qiaoran Qi, Shuqin Zhuang, Olivia Qin, Ming Lin, Jiaying Zhang, Jin Li.
Title: Visual Development in Children With Marcus Gunn Jaw-Winking Syndrome and Congenital Blepharoptosis: Early Intervention Considerations.
Fulltext Link: https://doi.org/10.1016/j.edisc.2026.100068
About Eye Discovery
Eye Discovery is an open-access, peer-reviewed international academic journal, with ISSN 3117-4167. It is published quarterly by Elsevier and serves as the official journal of Eye & ENT Hospital of Fudan University, China.
Eye Discovery is dedicated to creating a high-end platform for ophthalmologists, scientists, and scholars worldwide to focus on innovative achievements in ophthalmology and interdisciplinary fields, and to promote academic dissemination and exchange.
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