Teaching case. The child is five, esotropia at near, "refraction through an undilated pupil +1.25". Weak glasses were prescribed, the angle did not decrease, acuity of the worse eye is static. After cycloplegia, +4.50. This is not "the eye changed in a week". It is accommodation that was not switched off.
PPP: determining the refractive error is critical for the diagnosis and treatment of amblyopia and strabismus. Cycloplegic refraction with retinoscopy is needed, followed by subjective refinement when the child is capable. Retinoscopy before cycloplegia (dynamic) quickly shows whether there is accommodation on a near target and is useful for asthenopia and suspected accommodative insufficiency — but for prescribing amblyopia glasses, relying on "the undilated pupil" is not enough. In children accommodation is stronger than in adults.
There is no ideal cycloplegic agent: the PPP states directly that there is no agent that is simultaneously safe, fast, adequate and free of systemic effects. The document's working scheme:
- Cyclopentolate 1% — the typical choice in term infants older than 12 months: rapid cycloplegia approximating atropine 1%, shorter in duration. The dose is chosen according to weight, iris colour and previous response.
- Dark iris: repeat drop or adjuvants — phenylephrine 2.5% (produces no cycloplegia) or tropicamide 1.0%.
- Tropicamide 0.5% + phenylephrine 2.5% — a possible combination for dilation and cycloplegia.
- Under 6 months: often a combination of cyclopentolate 0.2% and phenylephrine 1%. Higher concentrations or a repeat are sometimes needed.
- Rarely — atropine sulfate 1% for maximal cycloplegia.
An anaesthetic drop before the cycloplegic reduces stinging and improves penetration. Short-lived systemic effects listed by the PPP: hypersensitivity, fever, dry mouth, tachycardia, nausea, vomiting, flushing, drowsiness, and rarely behavioural changes up to delirium. Punctal occlusion reduces systemic absorption. For a severe reaction — emergency care; the PPP mentions physostigmine as a possible agent in this context.
Why such pharmacology in a course on amblyopia. Because an error of cycloplegia changes the form. Under-cyclopleged hyperopia hides anisometropia, hides accommodative esotropia, produces "normal" instead of isoametropia. The "weak" glasses prescribed do not treat the input, and then the resident honestly writes "occlusion is not helping". It is not the patch that is failing — it is the uncorrected defocus.
Subjective refinement. When the child is capable, it is added. When not — retinoscopy under cycloplegia remains the main number, and this is normal, not a deficiency of the examination.
Alignment is measured before cycloplegia: the angle may change. Refraction for prescribing is done under cycloplegia. Two different times, two different questions.
Boundary. The course does not replace a pharmacology reference and does not fix "a single drop for every iris in Kazakhstan". It fixes the PPP principle: without adequate cycloplegia, the diagnosis of refractive and mixed amblyopia is incomplete.