Topic 1: Anterior Segment Dysgenesis, Aniridia, Microphthalmos, Coloboma, and Albinism
1. Anterior Segment Dysgenesis (ASD)
Anterior Segment Dysgenesis (ASD) is a group of developmental anomalies resulting from disrupted embryogenesis of the anterior chamber structures including the cornea, iris, lens, and angle. These defects are usually congenital and may be isolated or part of systemic syndromes like Axenfeld-Rieger Syndrome or Peter’s Anomaly.
Clinical Features
- Posterior embryotoxon (thickened Schwalbe's line visible on slit lamp)
- Corectopia (displacement of pupil)
- Iris strands adherent to cornea or trabecular meshwork
- Corneal opacities
- Secondary glaucoma is common
Optometric Management
- Monitor intraocular pressure regularly due to high glaucoma risk
- Visual acuity correction with glasses or low vision aids if opacities reduce clarity
- Early referral to pediatric ophthalmology for surgical evaluation
- Genetic counseling for syndromic cases
Prognosis
Visual prognosis depends on the severity and extent of involvement. Children with associated glaucoma or central opacities may have guarded vision outcomes. Early diagnosis and low vision rehabilitation are critical.
2. Aniridia
Aniridia is a congenital, bilateral absence or severe underdevelopment of the iris. It may be isolated or syndromic (e.g., WAGR syndrome). PAX6 gene mutation is most commonly involved.
Clinical Features
- Partial or near-total absence of iris tissue
- Photophobia and reduced visual acuity
- Associated with foveal hypoplasia, nystagmus, and cataracts
- High risk of secondary glaucoma and corneal opacification (aniridic keratopathy)
Optometric Management
- Tinted contact lenses or cosmetic lenses to reduce photophobia
- Visual acuity correction using spectacles with UV protection
- Monitoring for glaucoma, cataract, and corneal changes
- Low vision aids and educational support when needed
Prognosis
Vision may remain subnormal due to foveal hypoplasia and other structural issues. However, early intervention, use of tinted lenses, and monitoring of complications can significantly improve quality of life.
3. Microphthalmos
Microphthalmos refers to an abnormally small eyeball, which may be isolated or part of syndromic anomalies. It results from incomplete eye development during embryogenesis.
Types
- Simple microphthalmos: Small eye but otherwise structurally normal
- Complex microphthalmos: Associated with coloboma, retinal detachment, or other defects
Clinical Features
- Small corneal and axial length (confirmed via ultrasound/biometry)
- High hypermetropia
- Often associated with other anomalies like cataract or coloboma
- May be unilateral or bilateral
Optometric Management
- Full hyperopic correction to prevent amblyopia
- Low vision aids for severe forms
- Cosmetic prosthesis or conformers in severe unilateral cases with no visual potential
- Referral to ocularist and pediatric ophthalmologist for management planning
Prognosis
The visual prognosis varies from near-normal to severe vision loss depending on the associated anomalies. Early optical correction and amblyopia therapy are crucial in visual rehabilitation.
4. Coloboma
Coloboma is a congenital defect resulting from incomplete closure of the embryonic fissure during fetal development. It may affect the iris, retina, choroid, or optic disc.
Clinical Features
- Iris coloboma: keyhole-shaped pupil usually inferonasally
- Chorioretinal coloboma: white or pale defect in the retina or choroid
- Optic disc coloboma: excavated appearance of the optic nerve head
- Can be associated with microphthalmos or nystagmus
Optometric Management
- Photochromic or tinted lenses for iris coloboma to reduce photophobia
- Low vision aids if posterior coloboma reduces acuity
- Monitor for retinal detachment in choroidal coloboma
- Protective eyewear due to risk in functional monocular patients
Prognosis
Iris colobomas may have minimal visual impact, while choroidal or optic disc colobomas may cause significant visual impairment. With proper optical aids and monitoring, functional vision can be supported.
5. Albinism
Albinism is a group of inherited disorders characterized by reduced or absent melanin pigment in the skin, hair, and eyes. Ocular albinism primarily affects the eyes, while oculocutaneous albinism affects both eyes and skin.
Clinical Features
- Hypopigmented iris and retina
- Nystagmus, photophobia, and foveal hypoplasia
- Reduced visual acuity (20/60 to 20/400)
- Misrouting of optic nerve fibers leading to poor binocular vision
Optometric Management
- Photochromic or tinted glasses to manage photophobia
- High-plus lenses, bifocals, and cylinder correction as needed
- Telescopic aids or magnifiers for near and distance tasks
- Orientation and mobility training in severe cases
- Genetic counseling and supportive education planning
Prognosis
Though vision remains subnormal, many children with albinism achieve functional independence with proper optical correction, lighting adjustments, and educational support. Early low vision assessment is key.
Conclusion
Congenital structural anomalies like anterior segment dysgenesis, aniridia, microphthalmos, coloboma, and albinism pose significant visual challenges in pediatric patients. Optometrists play a critical role in early detection, optical correction, low vision rehabilitation, and multidisciplinary management. Early intervention and tailored support can significantly improve quality of life and learning outcomes for affected children.
Topic 2: Spectacle Dispensing for Children
Spectacle dispensing for children is a specialized and critical area in pediatric optometry. Properly designed and fitted spectacles not only correct refractive errors but also play a pivotal role in the treatment of amblyopia, strabismus, and binocular vision anomalies. Children are not just miniature adults — they have unique anatomical, visual, psychological, and practical needs that must be taken into account when dispensing spectacles.
1. Importance of Proper Spectacle Dispensing in Children
In children, accurate and comfortable spectacle wear can:
- Prevent amblyopia by providing proper refractive correction
- Improve academic performance and learning ability
- Support the treatment of strabismus and accommodative issues
- Enhance confidence and social behavior in school settings
2. Challenges in Pediatric Dispensing
Dispensing spectacles to children presents specific challenges such as:
- Smaller facial and nasal anatomy requiring special frame design
- High activity levels — glasses must be impact-resistant and durable
- Rapid physical growth, requiring frequent refitting or adjustments
- Children may be less expressive about discomfort, so careful observation is needed
3. Frame Selection for Children
The choice of frame is vital for comfort, compliance, and durability. Important factors include:
a. Material
- Plastic frames: Lightweight, colorful, and generally hypoallergenic. TR90 material is preferred for its flexibility and toughness.
- Metal frames: More durable and adjustable, but require hypoallergenic options like stainless steel or titanium.
b. Bridge Fit
- Children have underdeveloped nasal bridges, so the frame should have proper saddle bridges or silicone nose pads to prevent slipping.
c. Temple Design
- Spring hinges and wrap-around temples or elastic straps help keep spectacles in place during activity.
d. Frame Size and Adjustment
- Frame width should match the face — temples should not press against ears or flare outward
- Lens centers must align with the child’s pupils for optical accuracy
4. Lens Selection for Children
a. Material
- Polycarbonate: Preferred for all pediatric lenses due to impact resistance, light weight, and UV protection.
- Trivex: Offers similar benefits with better optical clarity but at higher cost.
b. Lens Design
- Single vision: Most common for correcting myopia, hyperopia, or astigmatism
- Bifocals/Progressive lenses: Used for accommodative esotropia, high near demand, or in conditions like Down syndrome
c. Coatings
- Anti-reflective coating: Improves clarity, reduces eye fatigue, especially useful for digital screen exposure
- Scratch-resistant coating: Essential for children's lenses
5. Prescription Considerations
- Full correction is essential for amblyopia, anisometropia, or strabismus
- In hyperopia, partial correction may be prescribed based on age, symptoms, and binocular status
- Prescribe based on cycloplegic refraction and binocular vision findings
6. Dispensing Tips for Optometrists
- Always double-check lens centration, segment height (for bifocals), and pupillary distance
- Involve the child in frame selection to boost compliance and ownership
- Demonstrate proper spectacle care to child and parents
- Educate caregivers about signs of discomfort: redness, indentation marks, squinting, or refusal to wear
- Schedule regular follow-ups for fit adjustment and prescription review
7. Counseling and Parental Education
- Explain the importance of full-time wear (especially in amblyopia or strabismus)
- Discuss need for frequent refitting due to growth
- Encourage backup pair due to risk of breakage or loss
- Instruct to avoid frequent frame swaps as it may confuse visual development
8. School and Social Considerations
- Help children build confidence by normalizing glasses use
- Educate teachers about the child’s visual needs and ensure front seating if needed
- Encourage participation in physical activity with sports goggles or straps
Conclusion
Spectacle dispensing for children is not merely about correcting refractive errors — it's about safeguarding visual development, ensuring compliance, and promoting functional independence. Pediatric dispensing requires a patient, attentive, and child-friendly approach, with close collaboration between the optometrist, parents, and child. With proper frame selection, lens safety, and ongoing support, children can achieve excellent vision and confidence during their critical growth years.
Topic 3: Pediatric Contact Lens
The use of contact lenses in pediatric patients has evolved significantly in the last few decades. While once considered only for older teenagers and adults, contact lenses are now routinely prescribed for infants, toddlers, and young children under special circumstances. With advancements in lens materials, oxygen permeability, and fitting techniques, pediatric contact lenses serve as essential tools for managing various visual conditions, including high refractive errors, anisometropia, aphakia, keratoconus, and cosmetic rehabilitation.
1. Importance and Indications
Contact lenses in children are not merely cosmetic. They serve critical optical, therapeutic, and functional roles:
- Aphakia: In infants post-congenital cataract surgery, contact lenses provide optical correction when intraocular lens (IOL) implantation is not performed.
- High refractive errors: Especially in cases of high myopia, hyperopia, or astigmatism where spectacles are impractical or cosmetically unacceptable.
- Anisometropia: Contact lenses eliminate image size differences (aniseikonia), improving binocular vision and preventing amblyopia.
- Keratoconus or irregular corneas: Gas permeable or hybrid lenses provide better visual acuity than glasses.
- Cosmetic/occlusive lenses: For children with corneal scars, leukomas, aniridia, or trauma-related disfigurement.
- Myopia control: Orthokeratology and soft multifocal lenses are proven to slow the progression of myopia in school-aged children.
2. Types of Contact Lenses Used in Children
a. Soft Contact Lenses
- Made of hydrogel or silicone hydrogel
- Comfortable and easy to adapt
- Common in older children for daily wear or myopia control
- Available as daily, bi-weekly, or monthly disposables
b. Rigid Gas Permeable (RGP) Lenses
- Used in corneal irregularities, keratoconus, and high refractive errors
- Provide superior optics and oxygen permeability
- Require adaptation and parental involvement in handling
c. Hybrid Lenses
- Rigid center with soft skirt
- Combines the clarity of RGP and comfort of soft lenses
d. Scleral Lenses
- Large diameter lenses vaulting the cornea and resting on sclera
- Ideal for severe ocular surface disease, keratoglobus, or pediatric keratoconus
e. Ortho-K Lenses (Orthokeratology)
- Worn overnight to temporarily reshape the cornea
- FDA-approved for myopia control
- Popular in school-aged children with progressive myopia
f. Cosmetic/Prosthetic Lenses
- Used for cosmetic enhancement or disfigurement (e.g., corneal scars, coloboma)
- Can include painted lenses or occlusive designs for amblyopia therapy
3. Contact Lens Fitting Considerations in Children
a. Age and Maturity
- Infants and toddlers rely on parents for application and care
- Children aged 8–10 may begin independent wear with supervision
- Maturity, hygiene habits, and family commitment are more important than chronological age
b. Corneal Parameters
- Keratometry or corneal topography is critical for lens design
- Infant corneas are steeper and smaller in diameter, requiring customized lenses
c. Lens Movement and Fit
- Should allow sufficient tear exchange, centration, and stability
- Assessment with fluorescein (for RGPs) or slit-lamp evaluation for soft lenses
d. Oxygen Permeability
- Essential to prevent hypoxic complications in young eyes
- Use high Dk materials especially in extended wear or therapeutic use
4. Contact Lens Care and Hygiene
Parental involvement is essential in children below 10–12 years. Important care aspects include:
- Daily cleaning, rinsing, and disinfecting with multipurpose or hydrogen peroxide systems
- Proper hand hygiene before lens handling
- Routine replacement of lenses and cases
- Strict avoidance of sleeping in lenses unless prescribed (e.g., Ortho-K)
5. Complications and Risk Management
Common Complications
- Conjunctivitis: Can be bacterial, viral, or allergic
- Corneal hypoxia: More common with low Dk lenses or extended wear
- Giant Papillary Conjunctivitis (GPC): Especially in reusable soft lenses
- Corneal ulcers or infections: Rare but vision-threatening; require immediate discontinuation and medical care
Prevention Strategies
- Frequent follow-up (every 3–6 months)
- Parental and child education on signs of infection (redness, discharge, pain)
- Using daily disposables in children with poor compliance or hygiene
6. Counseling and Education
- Assess motivation and expectations of both child and parents
- Demonstrate lens insertion/removal using models or videos
- Give written instructions and emergency contact info
- Encourage routine checkups for lens fit, ocular health, and visual needs
7. Role of Optometrist
The optometrist is central to successful pediatric contact lens wear:
- Identifies appropriate candidates based on clinical need and maturity
- Performs accurate fitting and ensures proper movement and centration
- Monitors ocular health and growth-related changes
- Manages complications promptly
- Educates families and coordinates with schools or therapists if needed
8. Case Examples
- Infant Aphakia: After congenital cataract surgery, silicone hydrogel contact lenses offer a temporary optical solution until secondary IOL implantation.
- High Anisometropia: A 6-year-old with +6.00 D in one eye and plano in the other is fitted with a soft lens to reduce aniseikonia and stimulate binocular development.
- Progressive Myopia: A 10-year-old with -4.00 D progressing yearly is placed on Ortho-K therapy and monitored regularly.
Conclusion
Pediatric contact lenses are more than visual aids — they are essential therapeutic tools for treating refractive, binocular, and developmental ocular conditions. Successful outcomes depend on proper patient selection, skillful fitting, close follow-up, and effective parent-child education. With advances in contact lens materials and designs, optometrists are now better equipped than ever to enhance the visual and functional lives of children through safe and effective contact lens wear.
Topic 4: Low Vision Assessment in Children
Low vision in children is a complex and challenging condition where visual function is impaired to the extent that it interferes with daily activities, learning, or mobility, but where useful vision still exists. It is defined as a permanent visual impairment not correctable by conventional glasses, contact lenses, or surgery. Unlike adults, children with low vision may have congenital or early-onset causes, and early assessment and intervention can dramatically improve their functional outcomes.
1. Definition of Low Vision
According to the World Health Organization (WHO), low vision is defined as:
- Best corrected visual acuity (BCVA) in the better eye less than 6/18 but equal to or better than 3/60
- Or a significant visual field loss (less than 10° from fixation)
However, in children, functional definitions are often more useful, focusing on how visual limitations affect learning, reading, orientation, and mobility.
2. Common Causes of Pediatric Low Vision
a. Congenital Conditions
- Albinism
- Optic nerve hypoplasia
- Congenital cataracts (unmanaged)
- Leber’s congenital amaurosis
- Coloboma
b. Acquired Conditions
- Retinopathy of prematurity (ROP)
- Traumatic eye injury
- Infectious causes (e.g., toxoplasmosis, rubella)
- Brain injury or cerebral visual impairment (CVI)
c. Progressive Conditions
- Retinitis pigmentosa
- Stargardt disease
- Macular dystrophies
3. Importance of Early Low Vision Assessment
Children with low vision are often at risk of:
- Delayed motor and cognitive development
- Educational difficulties and literacy delay
- Social withdrawal or behavioral issues
- Dependence on caregivers
Early detection and support from optometrists, educators, and rehabilitation specialists can foster independence, confidence, and academic achievement.
4. Components of Pediatric Low Vision Assessment
a. Case History
- Detailed birth and medical history
- Family history of hereditary eye diseases
- Developmental milestones and cognitive status
- Previous treatments, surgeries, or therapies
- Parental concerns regarding reading, mobility, or school performance
b. Visual Acuity Testing
- Use of age-appropriate and low vision charts (Lea symbols, Bailey-Lovie, ETDRS)
- Distance and near VA measured monocularly and binocularly
- Test with habitual correction, then trial lenses
c. Visual Field Evaluation
- Confrontation field testing for gross field defects
- Tangent screen or Goldmann perimetry in cooperative children
- Observation of navigation and mobility also reveals functional field loss
d. Contrast Sensitivity
- Low contrast can affect reading and facial recognition
- Pelli-Robson or Lea contrast tests used
e. Color Vision Testing
- Use Ishihara, Hardy-Rand-Rittler (HRR), or Color Vision Made Easy cards
f. Oculomotor Evaluation
- Assess fixation, pursuits, saccades
- Eye movement instability may require visual tracking training
5. Functional Vision Assessment
A crucial part of pediatric low vision care is understanding how the child uses vision in real-life settings:
- Does the child hold objects close?
- Can the child follow faces or lights?
- What lighting conditions are preferred?
- Is head posture altered to optimize vision?
6. Low Vision Devices for Children
a. Optical Aids
- Magnifiers: Dome, stand, handheld, or illuminated types
- Telescopes: Monocular or bioptic for distance viewing
- High-add spectacles: Useful for continuous near tasks
b. Non-Optical Aids
- Reading stands to maintain working distance
- Typoscopes for line guidance
- High contrast notebooks and writing guides
c. Electronic Devices
- Closed-circuit televisions (CCTV) or video magnifiers
- Tablets with screen magnification and contrast control
- Screen-reading and text-to-speech software
7. Rehabilitation and Support Strategies
Low vision rehabilitation must be multidisciplinary:
a. Educational Support
- Introduce Braille if necessary for children with profound vision loss
- Use large-print books, audio resources, and contrast-enhancing materials
- Ensure inclusive classroom environment with proper seating and lighting
b. Orientation and Mobility Training
- Teaches safe and confident movement through familiar and unfamiliar environments
- Includes cane training, echolocation techniques, and spatial awareness
c. Counseling and Parental Guidance
- Help parents understand their child’s visual abilities
- Encourage independence and avoid overprotection
- Discuss prognosis realistically while focusing on possibilities
8. Optometrist’s Role in Low Vision Care
The optometrist acts as the primary professional in identifying and supporting children with low vision:
- Conducts comprehensive functional assessments
- Prescribes appropriate low vision aids and trains children in their use
- Coordinates with special educators, pediatricians, and therapists
- Monitors visual function over time and adjusts prescriptions
- Educates parents and helps them access disability support programs
9. Legal and Social Considerations
- Children with BCVA <6 and="" as="" be="" benefits="" blind="" classified="" entitled="" field="" legally="" li="" may="" or="" to="" visual="">
- Certificates enable access to assistive devices, special schools, and financial support
Conclusion
Low vision in children presents a lifelong challenge, but with early detection, multidisciplinary rehabilitation, and proper assistive technologies, affected children can achieve educational success and independence. The optometrist plays a central role in ensuring that every child with visual impairment is empowered with the tools and training needed to make the most of their remaining vision.
For more units of Pediatric Optometry click the link below 👇
👉 Unit 3
👉 Unit 4
These notes are curated to help Bachelor of Optometry students revise key topics in a simplified and exam-focused format. While they are comprehensive and based on the official syllabus, they are not intended to replace standard textbooks, research publications, or clinical guidelines. To build deeper conceptual understanding and clinical competence, students are strongly encouraged to:
- Refer to prescribed textbooks and reference books
- Stay updated with current clinical practices and evidence-based resources
- Participate in clinical postings, case discussions, and hands-on training
