Question:easy
Second sight is seen in which type of cataract?
Second sight is seen in which type of cataract?
Show Hint
Which cataract raises the lens refractive index and induces index myopia?
Updated On: Jun 24, 2026
- Nuclear cataract
- Cortical cataract
- Zonular cataract
- Punctate cataract
Show Solution
The Correct Option is A
Solution and Explanation
Step 1: The phrase second sight describes an elderly patient who finds that reading suddenly becomes easier, occasionally being able to read newsprint without spectacles, which is a transient gift soon overtaken by worsening lens opacity.
Step 2: The optical reason is a rise in the refractive index of a hardening, sclerosing lens nucleus. A higher index lens bends light more strongly, inducing a myopic shift that brings near targets into sharp focus, an effect called index myopia.
Step 3: Since only nuclear sclerosis changes the index of the central lens substance, this phenomenon is tied exclusively to nuclear cataract.
Step 4: The remaining options act elsewhere in the lens, cortex, zonular lamellae, or punctate dots, and never increase nuclear refractive power, so they cannot give second sight.
\[\boxed{\text{Nuclear cataract}}\]
Step 2: The optical reason is a rise in the refractive index of a hardening, sclerosing lens nucleus. A higher index lens bends light more strongly, inducing a myopic shift that brings near targets into sharp focus, an effect called index myopia.
Step 3: Since only nuclear sclerosis changes the index of the central lens substance, this phenomenon is tied exclusively to nuclear cataract.
Step 4: The remaining options act elsewhere in the lens, cortex, zonular lamellae, or punctate dots, and never increase nuclear refractive power, so they cannot give second sight.
\[\boxed{\text{Nuclear cataract}}\]
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