Ophthalmology and ENT — Refractive Error and the Nose, NMC MBBS licence examination syllabus (Nepal Medical Council).
A child failing at school and an adult whose eye is swelling next to a sinus infection are both, in different ways, urgent.
This chapter covers two areas the syllabus names specifically and that the earlier chapters did not reach: refractive error, which is the commonest cause of poor vision in the world and the cheapest to fix, and the nose, where a very common complaint occasionally sits next to the orbit and the brain.
The eye is a lens system focusing light onto the retina. A refractive error means the image does not land there, and the whole classification follows from asking where it lands instead.
Myopia — short sight. The image falls in front of the retina, because the eye is too long or its optics too powerful. Distant objects blur while near ones stay clear, which is why a myopic child sits close to the board and holds books close. Corrected with a concave (diverging) lens.
Hypermetropia — long sight. The image would fall behind the retina. Near work blurs first. The important subtlety is that a young eye can partly compensate by accommodating — so a hypermetropic child may see well but complain of eye strain and headache after reading, because the effort is constant. Corrected with a convex (converging) lens.
Astigmatism. The eye's optical power differs between meridians, so there is no single point of focus at any distance. Vision is blurred both near and far, and correction requires a cylindrical lens.
None of these is a disease of the eye. The eye is healthy; its dimensions do not match its optics. That distinction matters clinically, because a patient whose vision improves fully with a pinhole or with lenses has a refractive problem, whereas one whose vision does not improve has something wrong with the eye itself and needs examining.Presbyopia is often lumped in with the refractive errors and is not one. The lens stiffens with age and loses the ability to change shape, so accommodation fails — the eye can no longer adjust focus for near work.
The history is characteristic: a person in middle age who has started holding things further away to read, finds it worse in dim light and when tired, and whose distance vision is unchanged. Reading glasses solve it. It happens to everyone eventually.
Uncorrected refractive error is among the leading causes of visual impairment worldwide, and the treatment is a pair of spectacles. Two consequences make it a clinical concern rather than an optical one.
In a school-age child, an uncorrected error affects learning. A child who cannot read the board is frequently described as inattentive, disruptive or slow, and acquires that label instead of the glasses that would have solved it.
In a young child, the stakes are higher. A persistently blurred image prevents that eye's visual pathway from developing — amblyopia, covered in the first ophthalmology chapter. Corrected early, vision develops normally; corrected after the developmental window closes, the vision is permanently lost even though the eye is structurally normal and the glasses are now correct.
So the practical instruction: test vision in any child who is struggling at school, and test each eye separately. A child with one good eye and one poor eye performs normally with both open and will not complain — which is exactly how a treatable amblyopia is missed until it is untreatable.Nasal obstruction is extremely common and almost always benign. The single most useful question is whether it affects one side or both.
Bilateral, with sneezing and clear discharge suggests rhinitis. Itch, watery eyes and a seasonal or exposure-related pattern favour an allergic cause; a short self-limiting course with a sore throat favours a viral one.
Bilateral, long-standing, with reduced sense of smell raises nasal polyps. The loss of smell is the useful clue, and polyps are associated with asthma and with aspirin sensitivity — so ask about both.
A deviated nasal septum is very common and mostly asymptomatic. It becomes relevant when obstruction is persistent, one-sided and troublesome enough to affect sleep or exercise — not simply because a deviation is visible.
Unilateral symptoms are a different question. In a child, persistent one-sided obstruction with foul discharge is a retained foreign body until proven otherwise. In an adult, unilateral obstruction — particularly with bleeding or foul discharge — requires examination to exclude a tumour. Bilateral is usually benign; unilateral earns a look.Most acute sinusitis is viral and resolves without antibiotics. The point worth carrying into practice is that coloured nasal discharge does not indicate bacterial infection and is not a reason to prescribe — it reflects the inflammatory cells present in any upper respiratory infection.
What matters far more than the antibiotic decision is recognising the complications, and the reason for them is anatomical: the orbit lies immediately beside the sinuses, separated by a thin plate of bone.
Eye signs demand urgent referral:
And beyond the orbit, intracranial spread presents with severe headache, altered consciousness, neck stiffness or focal neurological signs.
No dioptre values, acuity thresholds or antibiotic regimens appear here: acuity notation differs between systems, the need for correction depends on occupation and symptoms, and most sinusitis needs no antibiotic at all. Use your national guideline.
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