Which one is Against the Rule astigmatism
Correct Answer: + 2. 00 x 90deg
Description: Astigmatism:- Definition:- When the rays are focused at different points due to unequal refraction in different meridians. With the Rule Astigmatism:- * Veical meridian is more curved than the horizontal meridian * Eg : Normal eyes (0.25 D), pterygium * 90deg axis >>>> 180deg axis (+ lens at 90deg/- lens at 180deg) Against the Rule Astigmatism:- * When the horizontal meridian is more curved than the veical meridian * 180deg>>>>90deg axis (- lens at 90deg /+ lens at 180deg) * Eg: Post op astigmatism -suture related Oblique Astigmatism :- * The two principal meridias are at right angles to each other ; but not the veical and horizontal meridian like 45deg and 135deg Bioblique Astigmatism:- * The two principal meridias are not at right angles and also not the veical and horizontal meridia.eg : 30deg & 100deg Reference :- Parson's Diseases of the eye 22nd edition; page:- 53,76
Category:
Ophthalmology
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now