Paediatric Optometry
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Direct answer
A three-year-old cannot read Snellen letters, but vision is measurable at every age: preferential-looking cards (Teller) estimate acuity in infants, Lea symbols and HOTV matching carry the toddler years, and Snellen or logMAR charts arrive around five. Acuity matures from roughly 6/120 at birth toward 6/9 by age two to three and adult 6/6 by four to five years; fixation and following should be established by six to eight weeks, and stereopsis consolidates through the second six months. Every paediatric refraction is cycloplegic — the average neonate carries about +2.00 D of hyperopia that emmetropises by school age. Red flags demanding urgent referral are leukocoria, any squint persisting beyond three to four months, nystagmus, ptosis, and failure to fix and follow; in premature infants, retinopathy of prematurity screening (birth weight under 2000 g or gestation under about 32 weeks, first examination within about 30 days of life) is mandatory.
What you must remember
- Acuity milestones: about 6/120 at birth, 6/36 to 6/18 by one year, 6/9 by two to three years, adult 6/6 by four to five — always record which chart produced the score.
- Chart ladder: Teller and Cardiff cards under two years; Lea symbols, HOTV with matching card, Allen pictures at two to four; crowded logMAR or Snellen from about five — crowding bars matter because amblyopia hides behind single letters.
- Motility milestones: fixation and following by 6-8 weeks, convergence and accommodation established by 3-4 months; any manifest squint beyond 3-4 months is a referral, not a wait.
- Refraction: neonatal +2.00 DS average, emmetropising through childhood; always cycloplegic retinoscopy (cyclopentolate 1% standard, atropine 1% for the very young or esotropic).
- ROP screening (Indian national criteria): birth weight under 2000 g or gestational age under about 32-34 weeks per current national guidance, first examination by about 30 days of life, repeated by zone and stage.
- RBSK links: Rashtriya Bal Swasthya Karyakram screens birth-to-18-year-olds for the four Ds — defects at birth (including congenital cataract), diseases, deficiencies, developmental delays — at birth, 6 weeks, 9 months, 18 months, 2.5-3 years, then at school entry and periodically, routing eye findings to District Early Intervention Centres.
- Amblyopia risk factors: anisometropia from about 1.00 D, hyperopia beyond roughly +3.50 D, significant astigmatism, media opacity, or a family history of squint and high refractive error.
- Never defer: leukocoria (retinoblastoma until proven otherwise), infantile esotropia (surgery ideally inside the first two years), occluding ptosis.
The four-year-old examination, minute by minute
History first — birth, milestones, family squint or glasses — because prematurity and family history reframe everything. Engage the child with a distant toy; Hirschberg reflexes while she watches: symmetry excludes a large tropia. Cover test at distance and near, a flickering refixation grading the phoria. Acuity next, one eye occluded at a time: Lea symbols at 3 m down to the 6/9 line, then crowded bars. Near point of convergence on a fingernail; stereopsis with the Titmus fly — delight and data in one.
Then drops: van Herick, cyclopentolate 1%, punctum pressed, play interval. Forty minutes later, streak retinoscopy reads +3.00/+0.75 × 90 each eye — moderate hyperopia with mild with-the-rule astigmatism in an orthophoric, symmetric 6/9 child: observe, review in six months unless symptoms intervene. Had she shown a 12-prism-dioptre esotropia, the full plus would be prescribed today, because accommodative esotropia is treated optically before surgically. Fundus with the +20 D lens closes the visit — the paediatric eye earns a full look every time.
Camp realities examiners ask about
Programme mechanics dominate: how RBSK's mobile health teams screen at anganwadis and schools and refer to District Early Intervention Centres; why school screening uses the 6/9 line as its referral trigger; and why teachers can screen acuity but never judge squint or fundus. The perennial trap is the reassured parent: "the squint will straighten itself" is false for any manifest deviation past three to four months, whereas pseudostrabismus from epicanthic folds genuinely disappears — the cover test and corneal reflex, not the family photograph, decide.
Frequently asked questions
Which acuity charts suit a three-year-old?
Lea symbols or HOTV with a matching card at 3 metres, ideally with crowding bars; Snellen letters are reliable only from about age five.
When must an infant's squint be referred rather than observed?
Any manifest deviation beyond three to four months of age — infantile esotropia needs early assessment, often surgery within the first two years for binocular potential.
What are India's retinopathy of prematurity screening criteria?
Birth weight under 2000 g or gestational age under about 32 weeks (local protocols extend to 34), first examined within roughly 30 days of life.
What does RBSK screen for, and where do eye findings go?
The four Ds — defects at birth, diseases, deficiencies, developmental delays — from birth to 18 years at fixed ages, with eye conditions referred through District Early Intervention Centres.
Why is paediatric retinoscopy performed under cycloplegia?
Children accommodate strongly, masking hyperopia and distorting neutralisation; cycloplegia reveals the true refraction that governs safe prescribing in amblyopia and squint.