Questions and Answers
Which of the following medications is MOST likely to induce myopia?
What refers to an increased rate of molecular movement down its respective concentration gradient via help from carrier proteins?
Facilitated diffusion
Which symptom is MOST likely associated with olopatadine (Patanol) use?
What ophthalmic drop is of MOST benefit for moderate Fuch's dystrophy?
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A deficiency of which vitamin leads to prolonged dark adaptation?
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What is the resulting NET retinoscopy finding when neutralizing +1.50-1.50 x 090 with a working distance of 50 cm?
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Study Notes
Myopia Induction by Medications
- Recent onset of blurred distance vision may indicate myopia due to medication side effects.
- Isotretinoin, birth control pills, and diuretics are known culprits of drug-induced myopia.
- Myopia originates from corneal swelling, steepening the cornea's curvature; may also be due to lens swelling or ciliary body edema.
- Cessation or dose reduction of the offending drug usually reverses myopia.
Facilitated Diffusion
- Facilitated diffusion increases molecular movement down a concentration gradient through carrier proteins.
- Differs from passive diffusion, which does not involve carrier proteins and operates purely on concentration gradient principles.
- Active transport moves materials against their concentration gradient, requiring energy and specific carrier proteins.
- Group translocation involves chemical modifications during transport, such as phosphorylation of sugars.
Side Effects of Olopatadine (Patanol)
- Olopatadine is used for treating ocular allergies with dual-action mechanisms: blocking H1 receptors and stabilizing mast cells.
- Common side effects include stinging upon instillation, headaches, and an adverse taste.
- Severe adverse effects like tachycardia, depression, GI discomfort, and hallucinations are generally not reported.
Treatment for Fuchs' Dystrophy
- Moderate Fuchs' dystrophy presents with blurry vision, particularly in the morning, due to endothelial guttata.
- Sodium chloride drops are the most effective topical hyperosmotic agents for treating corneal edema from endothelial decompensation.
- Topical steroids can reduce inflammation, but in this case, inflammation is not a factor, making them less beneficial.
Vitamin A and Dark Adaptation
- Vitamin A deficiency leads to prolonged dark adaptation due to inadequate rhodopsin formation.
- Retinol, the active form of Vitamin A, is crucial for rod function in low-light conditions.
- Reduced rhodopsin limits the rods' ability to respond, necessitating more time to adapt to darkness.
Retinoscopy Findings
- A working distance of 50 cm generates a 2.00 D divergent wave that must be considered during retinoscopy.
- The spherical component of retinoscopy findings must be adjusted by subtracting +2.00 D due to the working distance effect.
- Understanding the reciprocal of the working distance is key: for 50 cm, the reciprocal (1/0.5) yields 2.
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Description
Test your knowledge with these flashcards focused on the National Board of Examiners in Optometry (NBEO) Part 1 topics. This quiz highlights important medical conditions as they relate to vision, including myopia induced by medications. Perfect for aspiring optometrists preparing for their exams.
