Abusive head trauma (AHT) is a general term for abusive head injuries in infants and young children. Formerly called shaken baby syndrome (SBS), the term AHT is now standardized as a broader concept that includes not only violent shaking but also impact-type injuries from striking the head 1).
AHT is classified into three types.
AHT (Shaken Baby Syndrome)
Mechanism: The abuser grasps the infant’s shoulders and shakes them violently back and forth, transmitting repeated acceleration-deceleration forces to the brain, retina, and optic nerve.
Main ocular findings: Numerous multilayered retinal hemorrhages extending from the posterior pole to the entire periphery, hemorrhagic retinoschisis, and retinal folds. These are seen in 80–85% of typical cases 1).
Characteristics: Bilateral simultaneous onset. Hemorrhages occur from both arteries and veins.
AHT (Blunt Force)
Mechanism: Brain and eye trauma from direct impact to the head.
Main ocular findings: Fundus changes at the impact site (coup) and opposite side (contrecoup). Upper facial impact can also cause trauma to the eyelids, cornea, iris, and lens1).
Characteristics: Bleeding tends to be localized around the impact site, differing from the widespread circumferential bleeding seen in shaking-type injuries.
AHT (Shaking + Impact)
Mechanism: Combined mechanism of shaking and impact.
Main ocular findings: Ocular findings of shaking type and impact type may coexist.
Features: Characteristic widespread hemorrhage of the shaking type may combine with local changes at the impact site1).
AHT is the leading cause of death from child abuse. The mortality rate is high at 15–38%, and only about 30% of patients recover normally. Even among survivors, 30–50% have some residual disability. Retinal hemorrhage is found in 85% of infants and young children who die from abusive head trauma.
The classic triad of AHT—subdural hematoma, ischemic brain injury, and retinal hemorrhage—has been widely cited as the historical concept of SBS. Among these, retinal hemorrhage is considered the finding most likely to result from violent shaking.
According to data from Western countries, about 25% of all AHT cases do not involve retinal hemorrhage, and mild to moderate hemorrhage accounts for approximately one-third of all cases2).
Infants with AHT are often brought to the emergency department with systemic symptoms such as impaired consciousness, seizures, poor feeding, and irritability. They cannot report eye symptoms themselves. Diagnosis depends on multidisciplinary assessment and fundus examination.
The sensitivity of retinal hemorrhage due to AHT reaches 85%, and specificity reaches 94%, contributing significantly to diagnosis. The characteristic fundus findings in typical cases (AHT shaking type) are that “in the absence of underlying systemic or ocular diseases, a very large number of retinal hemorrhages occur acutely, transiently, and simultaneously in both eyes, from both arteries and veins, extending from the posterior pole to the mid-periphery or periphery, circumferentially in all directions” 1).
Fundus findings
Characteristics
Frequency/diagnostic significance
Multilayered, multiple retinal hemorrhages
From posterior pole to entire periphery, from both arteries and veins. Dot, blot, flame-shaped, from preretinal to subretinal full-thickness vertically. If extending to periphery, more than 1,000 hemorrhagic spots
Sensitivity 85%, specificity 94%. Most common fundus finding in AHT
Hemorrhagic retinal schisis
Blood accumulation between internal limiting membrane and retinal layers. Often with a central white spot (Roth spot)
Seen in about 1/3 of AHT cases. Most specific finding. Outside abuse, limited to fatal traffic accidents, falls from ≥11 m, etc.
Retinal fold
Circular fold along the posterior pole vascular arcade (main fold) and secondary folds extending orthogonally and radially. Also peripapillary radial folds and branch folds along blood vessels.
Indicates that maximal vitreous traction has occurred. The most severe finding in classification.
As a feature of multilayered hemorrhage, the vertical distribution of bleeding extends not only through the full thickness of the retina but also to the epiretinal space (vitreous hemorrhage), subretinal space, and sometimes to the choroid1). Small punctate hemorrhages from capillaries (linear in the nerve fiber layer) are common. Horizontally, the hemorrhages spread across the entire fundus, and if they reach the periphery, approximately 1,000 or more hemorrhagic spots can be observed 1).
In each hemorrhagic spot or patch, the vessel wall is disrupted, and there is no component of exudation or leakage. Because the hemorrhage results from traumatic microvascular wall rupture, vasogenic extracellular edema, exudative spots (hard exudates), cellular edema, and soft exudates are not seen 1).
Hemorrhagic retinoschisis is the most specific retinal finding for AHT. It is observed in about one-third of all AHT/SBS cases. To date, this finding has been confirmed in non-abusive situations only under extremely limited circumstances, such as fatal traffic accidents, a falling object directly hitting the head, or a fall from a height of 11 meters or more.
Traction from vitreous fibers adhering to the vitreous surface often causes splitting of the retinal layers and separation of the internal limiting membrane. The presence of a central white spot (Roth spot) is a diagnostic clue.
Retinal folds indicate that the strongest possible vitreous traction, even greater than that causing retinal hemorrhage or retinoschisis, has occurred 1). They are often circular folds (main folds) along the posterior pole vascular arcades, with characteristic secondary folds extending perpendicularly or radially from them. Radial folds around the optic disc and branch-like folds along retinal blood vessels are also observed. When the layers are severely deformed, cell arrangement is disrupted, leading to loss of transparency and whitening.
Some cases have few hemorrhages, are limited to the posterior pole, or have no hemorrhages at all. However, if hemorrhages are confirmed from both arteries and veins, AHT is strongly suspected 1).
QWhat is the finding of hemorrhagic retinoschisis?
A
Hemorrhagic retinoschisis is a condition in which the retinal layers are separated by vitreous traction, and blood accumulates between the layers. Sub-internal limiting membrane hemorrhage is most common, often with a central white spot (Roth spot). It is found in about one-third of AHT cases and is considered the most specific fundus finding. Outside of abuse, it is confirmed only in extremely limited situations such as fatal traffic accidents or falls from 11 meters or more, so if this finding is present, it strongly suggests AHT.
The typical age of onset is around 1 year old in infants and toddlers. At this age, the head is proportionally large, neck muscles are underdeveloped, and head support is weak. Additionally, the brain is not fully myelinated, and the vitreous is firmly attached to the entire retina, making them susceptible to acceleration-deceleration forces from violent shaking.
According to the Ministry of Health, Labour and Welfare classification of abuse, there are four types: physical abuse, sexual abuse, neglect (including medical neglect), and psychological abuse. AHT is included in physical abuse.
A history of vaccination does not cause AHT. Seizures, coughing, vomiting, and apnea do not cause retinal hemorrhage 1). The movement of the vitreous body and the strength of traction are completely different between everyday shaking (nystagmus, eye movements, vehicle vibrations, vigorous exercise) and the violent, large-amplitude shaking of the head in AHT 1).
Typically, patients present to the emergency department with complaints of impaired consciousness, seizures, low-level falls, or other injuries, and are discovered after admission when an ophthalmology consultation is requested. Ophthalmologists rarely have the opportunity to examine the fundus findings caused by violent shaking1).
Pale retinal hemorrhages may disappear within 24 hours, and even typically, they are significantly absorbed within one week. It is desirable to perform a fundus examination within 24 hours of injury, and at the latest within 72 hours.
In deceased individuals, mydriatic agents are ineffective, but the pupils are slightly dilated, allowing fundus observation. Fundus examination can be performed up to 72 hours after death. This has important significance as a forensic record1).
Inspection of the external eye and anterior segment: Observe eye position, eye movements, pupillary reaction, external eye, and anterior segment first1).
Indirect ophthalmoscopy under mydriasis: Observe the entire fundus including the periphery (due to systemic management, the first examination may be performed without mydriasis).
Fundus chart documentation: Record using a chart format with two circles indicating the equator and the ora serrata. Document the distribution of hemorrhages (numerous, circumferential, nearly uniform) so that the overview is clear1).
Fundus photography: Photograph not only the posterior pole but also the mid-periphery and periphery.
Recording with wide-field fundus cameras (RetCam®, Optos®) is useful for objective documentation of the mid-periphery and periphery, and fundus chart drawings serve as evidence comparable to photographs1)3).
The minimum content that should be recorded as fundus findings is shown below.
Category
Checkpoints
Retinal hemorrhage
Number of hemorrhagic spots (a few, a dozen, too many to count), anteroposterior distribution (full-thickness or not), circumferential distribution (full circumference or not), uniformity, multilayered nature, vitreous hemorrhage, choroidal hemorrhage
Multiple small schises, hemorrhage with white spots, presence or absence of internal limiting membrane detachment and hemorrhage within it, shape of the edge
Retinal fold
Circumferential fold, secondary fold, radial folds around the optic disc, elevation along blood vessels
Chart entry
Age of hemorrhage, extent (entire circumference, mid-periphery, periphery), presence of “nearly uniform hemorrhage”
Photography
Fundus photographs of posterior pole, mid-periphery, and periphery
Localized near the posterior pole, does not spread to the entire fundus1)
Circulatory disturbance (venous stasis). In children, if coagulation is normal, increased intracranial pressure alone does not cause massive hemorrhage
Ocular contusion (single blow)
Coup/contrecoup only
A single blow does not cause widespread hemorrhage in all directions1)
Neonatal retinal hemorrhage
Hemorrhage due to passage through the birth canal. Centered at the posterior pole
Resolves within 2–6 weeks after birth1)
Convulsions
Do not occur1)
Retinal hemorrhage is not caused by convulsions
Chest compression (cardiac massage)
A few punctate hemorrhages in the peripapillary and posterior pole veins
Limited to a few punctate hemorrhages1)
Blood coagulation abnormality
Involved in increased bleeding
Does not directly cause multiple vascular wall ruptures1)
For differentiation from low-height falls, it is known that a single fall from a height of 1.2 m or more is required to cause a few small punctate or blotchy retinal hemorrhages in infants. If a child presents with multilayered, multiple retinal hemorrhages despite a history of “falling backward while standing holding onto something” or “falling off a sofa,” the history and medical findings are inconsistent, and abuse should be the first differential diagnosis.
QCan retinal hemorrhage occur from a low-height fall (e.g., from a sofa or bed)?
A
For an infant to develop a few small dot or blot retinal hemorrhages from a single low-height fall, a height of 1.2 meters or more is required. Falls from a standing position while holding onto furniture or from a sofa or bed (typically less than 60 cm) are unlikely to cause even this degree of retinal hemorrhage. Therefore, even if a low-height fall is reported, if multilayered, multiple, or widespread retinal hemorrhages are observed, abuse should be strongly suspected due to inconsistency between the history and findings.
QBy when should a fundus examination be performed?
A
It is desirable to perform the examination within 24 hours of injury, and at the latest within 72 hours. Faint retinal hemorrhages may disappear within 24 hours, and most are usually absorbed within one week. If the examination is performed after the hemorrhages have resolved, findings may not be captured. Therefore, when an infant suspected of abuse is brought in, prompt referral to an ophthalmologist should be made.
The diagnosis of AHT should not be made by an ophthalmologist alone, but based on comprehensive assessment by all departments including pediatrics, neurosurgery, neurology, orthopedics, radiology, pathology, and forensic medicine 1). The ophthalmologist participates in this multidisciplinary collaboration and contributes significantly to the diagnosis by providing information obtained from fundus findings.
A typical clinical flow is as follows 1).
Visit to emergency department with complaints of impaired consciousness, seizures, or low-level fall
Head CT, MRI, and systemic examination (evaluation by all departments)
Dilated fundus examination and documentation by ophthalmologist
Comprehensive diagnosis by all departments
AHT confirmed → Report to child consultation center
If uncertain, consult a specialist in retina or pediatric ophthalmology1).
Importance of medical records and fundus documentation
Fundus chart descriptions and wide-angle fundus camera images may be used as forensic evidence in court and legal proceedings. It is essential to objectively and thoroughly record the distribution, amount, morphology, and age of hemorrhages1).
QWhat should an ophthalmologist do when AHT is suspected?
A
The ophthalmologist does not diagnose AHT alone but participates in a multidisciplinary assessment. Perform a dilated fundus examination promptly, and record the amount, distribution, morphology, and age of hemorrhages in detail using fundus charts and photographs. If characteristic fundus findings are present, inform the pediatrician of suspected abuse and document appropriately in the medical record. If AHT is confirmed or strongly suspected, there is a mandatory duty to report to the Child Guidance Center (nationwide common dial 189). When in doubt, consult a specialist or specialized institution.
When an abuser grabs an infant around 1 year old by the shoulders and shakes them violently back and forth, the head moves greatly forward and backward, and repeated acceleration-deceleration forces are transmitted to the brain, retina, and optic nerve. In infants, the brain is not fully myelinated and is immature and vulnerable, leading to severe damage such as neurological impairment and bleeding due to vascular rupture.
In infants, the vitreous body is firmly attached to the entire retina. When the eyeball is shaken vigorously along with the head, the vitreous moves significantly, strongly pulling on the firmly attached retina. This traction force destroys blood vessel walls and causes retinal hemorrhage1).
Traction forces act not only vertically but in all directions, and rotational movements involving tangential motion relative to the retinal plane play a significant role 1). This explains why, in typical cases, numerous hemorrhagic spots and patches are widely distributed circumferentially from the posterior pole to the mid-periphery or periphery.
When traction intensifies further, not only does the vessel wall rupture, but the retinal layer structure itself is destroyed.
Retinoschisis: Traction by vitreous fibers adherent to the retinal surface causes splitting of the layer structure, leading to separation between retinal layers. Separation of the internal limiting membrane is common, but intraretinal splitting and mixed types also occur 1)
Retinal fold: When traction force becomes even stronger, the full thickness of the retina is lifted, forming a retinal fold. This indicates the strongest traction, greater than that causing hemorrhage or separation1)
Hemorrhage from both healthy arteries and veins without underlying disease occurs only in trauma1). Additionally, among traumatic causes, shaking in AHT is unique in that it rarely causes simultaneous hemorrhage in both eyes1).
The movement of the vitreous and the strength of traction are completely different between everyday shaking (nystagmus, eye movements, vehicle vibration, vigorous exercise) and violent head shaking in AHT. This is the biological basis for the differential significance of fundus findings in AHT1).
QCan retinal hemorrhage really occur just from shaking?
A
Everyday shaking (such as from vehicle vibrations, nystagmus, eye movements, or vigorous exercise) and the violent shaking in AHT result in completely different vitreous movement and traction forces. Retinal hemorrhage does not occur from everyday shaking. The typical fundus findings in AHT (multiple, multilayered hemorrhages from the posterior pole to the entire peripheral retina, hemorrhagic retinoschisis) are pathophysiological evidence of trauma caused by extremely strong force and vitreous traction. Retinal hemorrhage does not occur from vaccination, seizures, coughing, vomiting, or apnea.
AHT is the leading cause of death from child abuse. The mortality rate is 15–38%, and even among survivors, only about 30% achieve normal recovery. Residual disabilities include motor impairment, cognitive impairment, epilepsy, and visual dysfunction.
Even after retinal hemorrhage resolves, retinal disorders such as hemorrhagic retinoschisis may lead to chorioretinal atrophy after absorption, resulting in irreversible visual dysfunction. In particular, when the macula is involved, severe visual impairment may occur 1).
Since extensive hemorrhage temporarily impairs vision, AHT is recognized as a condition in which extensive hemorrhage or lesions occur in organs, leading to dysfunction 1). Retinal folds involve full-thickness elevation of the retina and are irreversible 1).
Vitreous surgery is mainly indicated for blunt trauma type, except in special cases. Prognostic factors affecting postoperative outcomes have been reported 7).
In 2025, the Japanese Ophthalmological Society, Japanese Association of Pediatric Ophthalmology, Japanese Society of Ophthalmic Surgery, and Japanese Society of Ocular Circulation jointly published “Guidelines for Abusive Head Trauma (AHT) in Infants and Young Children: How to Examine and Interpret the Fundus” 1). This guideline is a comprehensive reference citing 67 articles, clarifying that not only the “presence” but also the “distribution” of fundus findings has diagnostic significance.
Wide-field fundus cameras such as RetCam® and Optos® enable objective recording of the mid-peripheral and peripheral retina, contributing to improved diagnostic accuracy for AHT 1)3). Azuma et al. (2024) reported an evaluation of vitreous traction mechanisms in AHT using wide-field fundus photographs 3).
Optical coherence tomography (OCT) is useful for confirming retinal separation and retinal folds, and can provide detailed visualization of changes in retinal layer structure that are difficult to capture with fundus photography alone4).
Traction Force Simulation Using Finite Element Models
Computer simulation analysis of vitreoretinal interface traction in AHT is advancing, and attempts are being made to quantify the mechanical effects of violent shaking forces on the retina5).
Analysis of 110 autopsy eyes with AHT has revealed detailed laminar distribution of retinal hemorrhages and their mechanisms of occurrence6). Additionally, pathological analyses of macular retinoschisis and retinal folds have been reported8)9), accumulating scientific evidence for the diagnostic significance of fundus findings.
Ophthalmic Testimony in Judicial and Forensic Settings
Awareness of the evidentiary value of ophthalmic findings in diagnosing AHT is increasing, and standardized documentation of fundus charts and photographs plays an important role in judicial decisions1).
Narang SK, Haney S, Duhaime AC, et al. Abusive head trauma in infants and children: Technical Report. Pediatrics. 2025;155:e2024070457.
Azuma N, Yoshida T, Yokoi T, et al. Retinal hemorrhages and damages from tractional forces associated with infantile abusive head trauma evaluated by wide-field fundus photography. Sci Rep. 2024;14:5246.
Sturm V, Landau K, Menke MN. Optical coherence tomography findings in shaken baby syndrome. Am J Ophthalmol. 2008;146(3):363-368.
Suh DW, Song HH, Mozafari H, et al. Determining the tractional forces on vitreoretinal interface using computer simulation model in abusive head trauma. Am J Ophthalmol. 2021;223:396-404.
Breazzano MP, Unkrich KH, Barker-Griffith AE. Clinicopathological findings in abusive head trauma: analysis of 110 infant autopsy eyes. Am J Ophthalmol. 2014;158(6):1146-1154.
Ho MC, Wu AL, Wang NK, et al. Surgical outcome and prognostic factors after ophthalmic surgery in abusive head trauma. Retina. 2022;42(5):967-972.
Levin AV, Alnabi WA, Tang GJ, et al. Pathology of macular retinoschisis due to vitreoretinal traction in abusive head trauma. J AAPOS. 2018;22:E35.
Abed Alnabi W, Tang GJ, Eagle RC Jr, et al. Pathology of perimacular folds due to vitreoretinal traction in abusive head trauma. Retina. 2019;39:2141-2148.
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