What are the expected results of exams, including Visual Acuity (VA), Color Vision Testing, Goldmann Visual Field (GVF), Electroretinogram (ERG), and Fundus Photography, for retinoblastoma patients?

Expected Examination Results in Retinoblastoma Patients

For retinoblastoma patients, examination results typically show reduced visual acuity, abnormal color vision, constricted visual fields on Goldmann perimetry, diminished or extinguished responses on electroretinogram, and characteristic findings on fundus photography including white tumor masses, calcifications, and vascular abnormalities.

Visual Acuity (VA) Findings

Visual acuity in retinoblastoma patients varies based on tumor location and extent:

• Reduced VA when tumors involve the macula or optic nerve
• Potentially normal VA in peripheral tumors that spare central vision
• In advanced cases (Group D or E), significant visual impairment is common 1
• For children under 3 years, assessment focuses on fixation and following ability 2
• For children 3-5 years, standard visual acuity testing (Snellen letters, HOTV, LEA symbols) may show deficits 2

Color Vision Testing Results

• Abnormal color vision is common, particularly when tumors involve the macula
• Color vision defects correlate with the extent of retinal involvement
• The American Academy of Ophthalmology notes color vision testing as a specialized evaluation that may be indicated in retinoblastoma patients 2

Goldmann Visual Field (GVF) Findings

• Constricted visual fields corresponding to areas of retinal involvement
• Scotomas (blind spots) in areas corresponding to tumor location
• Field defects that correlate with the extent of retinal damage
• Superonasal field defects are common when inferotemporal retina is involved 2
• In advanced cases, significant peripheral field loss may be present

Electroretinogram (ERG) Results

ERG is particularly valuable in retinoblastoma evaluation:

• Diminished or extinguished responses proportional to the extent of retinal involvement
• Reduced a-wave and b-wave amplitudes
• Multifocal ERG (mfERG) may show localized depression in areas of tumor involvement 2
• ERG changes may precede clinically visible changes
• Can help differentiate retinoblastoma from simulating conditions 3

Fundus Photography Findings

Fundus photography reveals characteristic features:

• White or cream-colored tumor masses with calcifications
• Retinal vessel dilatation (observed in 46/47 Group D eyes) 4
• Small retinal vessel changes (35/47 Group D eyes) 4
• Retinal venous leakage (20/47 Group D eyes) 4
• Iris neovascularization (10/47 Group D eyes, 45/53 Group E eyes) 4

Specific Fundus Photography Modalities:

1. Color Fundus Photography:

   • White/cream-colored masses
   • Calcifications appearing as chalky white areas
   • Dilated, tortuous vessels
   • Secondary retinal detachment in advanced cases

2. Fundus Autofluorescence:

   • Hyperautofluorescence in areas of RPE alteration
   • Hypoautofluorescence in areas of calcification

3. Fluorescein Angiography:

   • Intrinsic tumor vessels
   • Areas of hyperfluorescence corresponding to tumor
   • Retinal venous leakage (20/47 Group D eyes) 4
   • Vascular abnormalities at multiple levels (11/53 Group E eyes) 4
   • Most clinically useful findings occur within first 3 minutes 4

Additional Important Considerations

• Examination under anesthesia is often necessary for comprehensive evaluation in young children
• Bilateral examination is crucial as 30-40% of cases are bilateral
• Regular follow-up examinations are essential to monitor treatment response
• MRI is the preferred imaging modality for diagnosis, staging, and treatment monitoring 5
• Retcam imaging has become valuable for documentation and monitoring 4

Common Pitfalls and Caveats

• Visual field testing may be challenging in young children due to cooperation issues
• ERG may require sedation in young patients
• Dilated fundus examination is essential but should be performed with caution if there is concern for increased intracranial pressure
• Misdiagnosis can occur with other conditions that simulate retinoblastoma
• Regular comprehensive examinations are crucial as treatment modalities have evolved significantly 1

The examination results should be interpreted in the context of the International Classification of Retinoblastoma (ICRB) staging to guide appropriate treatment decisions 1.