A. Optic Neuritis
B. Posterior subcapsular cataract
C. Retinopathy of prematurity
D. Retinitis Pigmentosa
- In most, clinical management, a topical steroid is used as a second step out of the three-step management of vernal catarrh.
- The topical Steroid is put at very minimally but if it is put for months and years, then it can result in either glaucoma or posterior Subcapsular cataract.
- Here the condition blurring of vision can never be a cause of glaucoma. So the answer here is Subcapsular Cataract.
2. A 23-year old medical student has been studying 10 hours a day for a week. The night before the exam he lands up with ocular pain and blurred vision for distance. What is the cause?
A. Asthenopia
B. Myopia
C. Ciliary Spasm
D. Hyperopia/Hypermetropia
- The answer is ciliary muscle spasm or accommodating spasm. Let' know the mechanism.
- The distance light rays equal to or more than 6 meters travels parallel and focus at the retina in an emmetropic eye.
- The near light rays are divergent( Basic Physics Principle) before entering into the cornea and later become parallel by the cornea, lens and also focuses later which means it focuses behind the retina.
- The lens changes its shape to more spherical by involuntary action of the ciliary muscle during prolonged near work.
- According to physics:- More spherical the surface, more power it becomes which means it becomes more powerful to bend the light rays.
- Now the eyeball is so powerful pulls the rays on the retina and this is how we accommodate or read the near objects.
- In this question, For the 10 hours, the ciliary muscle is accommodating or in a sustained contraction which makes ciliary spasm. So Zonules Relax and is not able to pull the lens(making Biconvex position). And the eyeball is so powerful to pull the light rays in front of the retina which is called Pseudo-Myopia(temporarily).
- In pseudo-myopia, the patient causes loss of distance rays.
- The distance light rays equal to or more than 6 meters travels parallel and focus at the retina in an emmetropic eye.
- The near light rays are divergent( Basic Physics Principle) before entering into the cornea and later become parallel by the cornea, lens and also focuses later which means it focuses behind the retina.
- The lens changes its shape to more spherical by involuntary action of the ciliary muscle during prolonged near work.
- According to physics:- More spherical the surface, more power it becomes which means it becomes more powerful to bend the light rays.
- Now the eyeball is so powerful pulls the rays on the retina and this is how we accommodate or read the near objects.
- In this question, For the 10 hours, the ciliary muscle is accommodating or in a sustained contraction which makes ciliary spasm. So Zonules Relax and is not able to pull the lens(making Biconvex position). And the eyeball is so powerful to pull the light rays in front of the retina which is called Pseudo-Myopia(temporarily).
- In pseudo-myopia, the patient causes loss of distance rays.
3. A 37-year old myopic(-4.0D/-1.0✖90) patient opts for contact lenses. To his surprise, he gets a crisp distant vision, but hazy near vision causes asthenopia. What could be the reason?
A. Contact Lens Intolerance
B. Dry eyes
C. Elimination of the prismatic effect of glasses
D. Contact lens allergy
- Here the clues to solve question is the age '37-years', 'refraction (-4.0D/-1.0✖90)' and 'not clear near vision'.
- Crisp distant vision and hazy near vision do not indicate About Contact lens intolerance.
- Dry eye is a problem for both distant and near vision.
- Contact lens allergy problem also for both distant and near vision.
- So the answer to this question is the elimination of the prismatic effect of glasses.
- This is the problem of many of us.
Prismatic effect of Lens:-
- Glasses are the combination of two prisms (we know from physics). Base to base prism makes Convex lens and apex to apex prism makes Concave lens.
- We all know that Prism bends the light rays toward the base.
- The concave lens bends the light rays towards the base. The apex to apex prismatic effect of concave glasses helps converge because they are pushing the light rays to the base.
- For near vision, there are three things that happen Accommodation, convergence, and miosis.
- The contact lenses are not a combination of prisms and the wearer losses prismatic effect when he switches from glasses to contact lenses.
- So wearer's whole effort falls in the medial rectus to cause the convergence.
- As he is 37 years old, he is a pre-presbyopia and this age patient falls to accommodate and converge because all his muscles become weakening, and the medial rectus is not so very powerful.
- So suddenly when he switches to a contact lens, the convergence helped by the glasses is not achieved by the contact lens.
- And he has to converge entirely by his own medial rectus which causes haziness and a lot of headaches.
- Crisp distant vision and hazy near vision do not indicate About Contact lens intolerance.
- Dry eye is a problem for both distant and near vision.
- Contact lens allergy problem also for both distant and near vision.
- So the answer to this question is the elimination of the prismatic effect of glasses.
- This is the problem of many of us.
Prismatic effect of Lens:-
- Glasses are the combination of two prisms (we know from physics). Base to base prism makes Convex lens and apex to apex prism makes Concave lens.
- We all know that Prism bends the light rays toward the base.
- The concave lens bends the light rays towards the base. The apex to apex prismatic effect of concave glasses helps converge because they are pushing the light rays to the base.
- For near vision, there are three things that happen Accommodation, convergence, and miosis.
- The contact lenses are not a combination of prisms and the wearer losses prismatic effect when he switches from glasses to contact lenses.
- So wearer's whole effort falls in the medial rectus to cause the convergence.
- As he is 37 years old, he is a pre-presbyopia and this age patient falls to accommodate and converge because all his muscles become weakening, and the medial rectus is not so very powerful.
- So suddenly when he switches to a contact lens, the convergence helped by the glasses is not achieved by the contact lens.
- And he has to converge entirely by his own medial rectus which causes haziness and a lot of headaches.
4. Which of the following is the most likely pupillary finding in an acute, isolated, complete 3rd nerve palsy due to an aneurysm?
A. Ipsilateral miosis
B. Relative Afferent Pupillary Defect(RAPD)
C. Light Near Dissociation
D. Ipsilateral Mydriasis
- The most common cause of 3rd nerve palsy is vasculopathy(Damaged to the blood vessel of the eye), uncontrolled diabetes, hypertension(HTN), and hypercholesterolemia.
- The 3rd nerve carries two different nerve fibers, Somatic fiber(Supplies to SR, IR, MR, IO muscles) and parasympathetic nerve supply(it causes pupil constriction and supplied to ciliary muscle).
- When there is a presence of an aneurysm at the junction of the posterior communicating artery(PCA) and Internal carotid artery(ICA) on which 3rd nerve passes, aneurysm presses the 3rd nerve and damages the para-sympathetic fibers because they are lying on the surface of the 3rd nerve.
- So the pupil can not constrict and correspond sympathetic fibers dilate the pupil.
- So that the answer to this question is ipsilateral Mydriasis.
Diagnosis of 3rd nerve Palsy:-
- Tricks to diagnose by down, out, and ptosis.
- The pupil could be normal size(Pupil Sparing) or it could be dilated(Mydriasis).
- The Pupil sparing 3rd nerve palsy is all about Medical causes that are either Diabetes(DM) and Blood Pressure(BP).
- The mydriatic pupil is all about surgical cases that are life-threatening aneurysms, tumors for which CT, MRI is needed to diagnose.
5. In an adult patient presenting with an acute, isolated unilateral 4th nerve palsy, which of the following is the most common etiology?
A. Myasthenia Gravis
B. Head trauma
C. Systemic Vasculitis
D. Midbrain infarction
- The 4th nerve palsy patient often comes with vertical diplopia or oblique diplopia and with hypertropia or hypotropia. Sometimes upward-inward of eyeball also seen.
- The muscle may involve are SR, IR, SO, IO. We find it with the help of PARK-Bielschowsky law.
- If the diplopia is worsening in downward or inward gaze in reading or walking downstairs, it tells us the diagnosis of the 4th nerve.
- The 4th nerve has unique four(4) different points:-
(a). Longest intra-cranial-Nerve(75mm)
(b). Thinnest intracranial nerve: So it gets easily damaged by Trauma without even opening of the skull or closed head injury.
- In adults most common cause of isolated 4th nerve palsy is head trauma and in children is congenital.
(c). It is the only nerve crossover That the right 4th nerve crossover supplies of the left superior oblique and left 4th nerve crossover supplies of the right superior oblique.
(d). It is the only nerve that comes from the dorsal surface of the brain stem.
