What are the possible causes and recommended evaluation for a four‑year‑old child presenting with a recessed (sunken) left eye?

Evaluation of a Recessed (Sunken) Left Eye in a Four-Year-Old

A four-year-old presenting with a recessed left eye requires urgent ophthalmologic evaluation to rule out serious orbital pathology, including orbital fractures, enophthalmos from trauma, orbital masses, or congenital orbital abnormalities that can threaten vision and require immediate intervention. 1, 2

Immediate Clinical Assessment

External Orbital Examination

• Assess the orbital anatomy systematically: examine the orbital rims for asymmetry, palpate for bony defects or step-offs suggesting fractures, and evaluate the position of the globe relative to the contralateral eye. 1
• Document head and face position: note any compensatory head tilt, turn, or chin positioning that may indicate the child is attempting to optimize vision or compensate for diplopia. 1, 3
• Inspect for facial dysmorphology: distinctive features including abnormal interocular distance, epicanthal folds, or craniofacial anomalies may suggest congenital orbital malformations. 1

Pupillary and Red Reflex Testing

• Perform pupillary examination in dim light: assess size, shape, and symmetry between the two eyes, as anisocoria >1mm is clinically significant and may indicate neurologic or structural pathology. 1, 4
• Execute the swinging-light test: an abnormal pupillary dilation when light is directed at the left eye indicates a relative afferent pupillary defect, suggesting optic nerve or retinal pathology. 1, 4
• Check the red reflex bilaterally: an absent, diminished, or asymmetric red reflex in the recessed eye may indicate media opacities, retinal abnormalities, or retinoblastoma requiring urgent referral. 4, 5

Ocular Motility and Alignment

• Perform corneal light reflex testing: observe whether the corneal reflexes are symmetric or if the left eye shows displacement, which would indicate strabismus. 1
• Execute cover testing in all gaze positions: any refixation movement indicates strabismus, and gaze-dependent deviation suggests incomitant strabismus from cranial nerve palsy, restrictive orbital disease, or muscle entrapment. 1, 3
• Assess fixation and following: the child should fixate steadily on age-appropriate targets and demonstrate smooth pursuit in all directions; poor fixation may indicate amblyopia or neurologic impairment. 1, 6

Differential Diagnosis by Clinical Context

Traumatic Causes (Most Urgent)

• Orbital floor or medial wall fracture with enophthalmos: blunt trauma can displace orbital contents into the maxillary or ethmoid sinuses, causing the globe to appear sunken and potentially entrapping extraocular muscles. 2, 7
• Globe luxation (rare): although typically presents with proptosis initially, subsequent repositioning or chronic displacement can alter globe position. 7

Congenital Orbital Abnormalities

• Congenital orbital asymmetry or hypoplasia: developmental anomalies may present with unilateral enophthalmos and require imaging to characterize bony and soft tissue structures. 2
• Craniofacial syndromes: conditions affecting orbital development may present with apparent globe recession due to abnormal orbital volume or shape. 1, 2

Orbital Masses or Infiltrative Disease

• Orbital tumors: masses within the orbit can displace the globe posteriorly or cause bony remodeling leading to apparent enophthalmos. 2
• Inflammatory or infectious processes: chronic orbital inflammation can cause fat atrophy and globe recession. 2

Pseudoenophthalmos

• Contralateral proptosis: the "recessed" appearance may actually reflect relative enophthalmos if the right eye is proptotic from thyroid eye disease, orbital mass, or vascular malformation. 2
• Ptosis or dermatochalasis: eyelid abnormalities can create the illusion of a sunken eye without true globe recession. 1

Urgent Referral Criteria

Immediate same-day ophthalmology referral is mandatory if any of the following are present:

• Abnormal or absent red reflex, suggesting retinoblastoma, cataract, or other vision-threatening pathology. 4, 5
• Relative afferent pupillary defect, indicating optic nerve or severe retinal disease. 1, 4
• Incomitant strabismus (deviation that varies with gaze direction), suggesting cranial nerve palsy, muscle entrapment, or restrictive orbital disease. 3
• History of recent trauma, particularly with periorbital ecchymosis, subcutaneous emphysema, or restricted ocular motility suggesting orbital fracture. 2, 7
• Acute onset with neurological symptoms such as headache, vomiting, altered mental status, or focal neurologic deficits. 6, 8

Specialist Evaluation and Imaging

What the Ophthalmologist Will Do

• Perform cycloplegic refraction to assess for significant refractive errors that may contribute to amblyopia risk. 1, 6
• Conduct detailed funduscopic examination after dilation to evaluate the optic disc, macula, retina, and choroid for structural abnormalities. 1
• Measure intraocular pressure if glaucoma is suspected based on corneal findings or optic nerve appearance. 1
• Assess for amblyopia through fixation preference testing and visual acuity measurement using age-appropriate methods. 6, 5

Imaging Indications

• Orbital CT is indicated when trauma is suspected, to evaluate for orbital fractures, foreign bodies, or globe rupture. 2, 8
• MRI is preferred for suspected orbital masses, optic nerve pathology, or intracranial extension of disease, as it provides superior soft tissue characterization without radiation exposure. 2, 8
• Neuroimaging is essential if there are signs of increased intracranial pressure (papilledema), cranial nerve palsies, or acute visual loss with normal anterior segment examination. 8

Critical Pitfalls to Avoid

• Do not dismiss this as normal facial asymmetry without systematic examination; true enophthalmos in a child warrants investigation for underlying pathology. 1, 2
• Do not delay referral for abnormal red reflex or pupillary findings, as conditions like retinoblastoma have time-sensitive treatment windows that directly impact survival and vision preservation. 4, 5
• Do not assume pseudoesotropia if strabismus is present; epicanthal folds may coexist with true strabismus, and both require evaluation. 1, 6
• Do not order imaging without clinical examination first, as the physical findings will guide appropriate imaging modality selection and prevent unnecessary radiation exposure. 1, 2