Nyctalopia in Children
Nyctalopia - Overview
Definition
Nyctalopia, or night blindness, is impaired vision in dim light and darkness, primarily affecting dark adaptation.
Key Points
- Can be congenital or acquired
- Often first symptom of retinal dystrophies
- May indicate systemic conditions
- Critical for early childhood development
- Can affect educational and social activities
Pathophysiology
Normal Dark Adaptation
- Rod Photoreceptor Function
- Rhodopsin cycling
- Vitamin A dependent process
- Neural signal transmission
- Retinal Pigment Epithelium Role
- Vitamin A metabolism
- Visual cycle maintenance
- Photoreceptor support
Pathological Changes
- Rod Dysfunction
- Genetic mutations
- Nutritional deficiencies
- Retinal degeneration
- Visual Cycle Disruption
- Vitamin A processing defects
- RPE dysfunction
- Metabolic disorders
Causes & Associations
Congenital Conditions
- Retinitis Pigmentosa
- Multiple genetic forms
- Progressive rod-cone dystrophy
- Early onset nyctalopia
- Congenital Stationary Night Blindness
- X-linked forms
- Autosomal forms
- Non-progressive
- Leber Congenital Amaurosis
- Severe early vision loss
- Multiple genetic variants
Acquired Causes
- Nutritional Deficiencies
- Vitamin A deficiency (most common)
- Zinc deficiency
- Protein malnutrition
- Retinal Diseases
- Chorioretinitis
- Central serous retinopathy
- Diabetic retinopathy
- Medications
- Ethambutol
- Isotretinoin
- Some antipsychotics
Diagnosis & Assessment
Clinical Evaluation
- History Taking
- Age of onset
- Progression pattern
- Family history
- Associated symptoms
- Physical Examination
- Visual acuity
- Color vision
- Visual fields
- Fundus examination
Specialized Testing
- Dark Adaptometry
- Gold standard test
- Measures adaptation threshold
- Quantifies severity
- Electroretinography (ERG)
- Rod and cone responses
- Disease classification
- Prognosis assessment
- Genetic Testing
- Gene panel testing
- Family screening
- Treatment planning
Management Approach
Treatment Strategies
- Nutritional Support
- Vitamin A supplementation
- Balanced diet
- Regular monitoring
- Genetic Counseling
- Family planning
- Prognosis discussion
- Support group referral
Vision Rehabilitation
- Adaptive Devices
- Night vision devices
- High-contrast materials
- Mobility aids
- Educational Support
- School accommodations
- Special lighting needs
- Safety measures
Monitoring & Prevention
- Regular Follow-up
- Vision assessment
- Disease progression
- Complication screening
- Preventive Measures
- UV protection
- Nutritional counseling
- Lifestyle modifications
