- 1. Antero-posterior diameter of normal adult eyeball is:
- A. 25 mm
- B. 24 mm
- C. 23.5 mm
- D. 23m
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Ans: B. 24 mm
The antero-posterior diameter is the longest axis of the eyeball, typically measuring 24 mm in adults. This measurement is essential in determining the axial length, which influences refractive errors. Variations in this diameter can lead to conditions like myopia or hyperopia.
- 2. Smallest diameter of the eyeball is:
- A. Vertical
- B. Horizontal
- C. Antero-posterior
- D. A & B
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Ans: A. Vertical
The vertical diameter of the eyeball is generally smaller than the horizontal diameter. This asymmetry plays a role in the anatomical structure and function of the eye.
- 3. Circumference of an adult eyeball is:
- A. 80mm
- B. 65mm
- C. 75mm
- D. 70mm
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Ans: C. 75mm
The average circumference of an adult eyeball is approximately 75 mm. This measurement helps in understanding the overall size and surface area of the eyeball.
- 4. Volume of an adult eyeball ls:
- A. 7.5ml
- B. 6.5mL
- C. 5.5mL
- D. 8.0 mL
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Ans: B. 6.5mL
The volume of the adult eyeball is around 6.5 mL, which is indicative of the total internal space of the eye. This volume is filled with various fluids like the aqueous and vitreous humor, essential for maintaining intraocular pressure and ocular function.
- 5. Weight of an adult eyeball is:
- A. 7g
- B. 9g
- C. 11 g
- D. 13g
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Ans: A. 7g
The average weight of an adult eyeball is approximately 7 grams. This lightweight structure supports the dynamic movement of the eye within the orbit.
- 6. Anterior segment of the eyeball includes structures lying in front of the:
- A. Iris
- B. Crystalline lens
- C. Vitreous body
- D. Cornea
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Ans: C. Vitreous body
The anterior segment refers to the part of the eye located in front of the vitreous body, including structures like the cornea, iris, and lens.
- 7. Posterior segment of the eyeball includes structures present posterior to the:
- A. Posterior surface of the lens and zonules
- B. Iris and pupil
- C. Vitreous body
- D. Anterior surface of the lens and zonules
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Ans: A. Posterior surface of the lens and zonules
The posterior segment of the eye includes the retina, choroid, and vitreous body, located behind the posterior surface of the lens and zonules.
- 8. Diameter of an adult crystalline lens is:
- A. 5-6mm
- B. 7-8mm
- C. 9- 10 mm
- D. 11-12mm
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Ans: C. 9- 10 mm
The adult crystalline lens has a diameter of about 9-10 mm, which is critical for the focusing power of the eye. The lens’s size and shape change with age and accommodation.
- 9. Thickness of the adult crystalline lens is about:
- A. 2.5mm
- B. 3.5mm
- C. 4.00mm
- D. 5mm
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Ans: C. 4.00mm
The thickness of the adult crystalline lens is approximately 4.00mm. This measurement increases with age, leading to a decrease in accommodative power.
- 10. Radius of curvature of the anterior surface of an adult crystalline lens with accommodation at rest is:
- A. 7mm
- B. 10mm
- C. 8mm
- D. 9mm
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Ans: B. 10mm
The radius of curvature of the anterior surface of the adult crystalline lens is about 10 mm when accommodation is at rest. This curvature allows the lens to refract light properly onto the retina.
- 11. Capsule of the crystalline lens is thinnest at:
- A. Anterior pole
- B. Posterior pole
- C. Equator
- D. None of the above
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Ans: B. Posterior pole
The lens capsule is the thinnest at the posterior pole, measuring about 4 micrometers. This thinness makes the posterior capsule more susceptible to tearing during cataract surgery.
- 12. Infantile nucleus of the crystalline lens refers to the nucleus developed from:
- A. 3 months of gestation to till birth
- B. Birth to one year of age
- C. Birth to puberty
- D. One year of age to 3 years of age
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Ans: C. Birth to puberty
The infantile nucleus forms after birth and continues to develop until puberty. It is situated around the embryonic and fetal nuclei and continues to grow throughout early childhood.
- 13. The lens fibers meet around the Y-shaped suture sin which part of nucleus of the crystalline lens:
- A. Embryonic nucleus
- B. Fetal nucleus
- C. Infantile nucleus
- D. All of the above
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Ans: A. Embryonic nucleus
The Y-shaped sutures are characteristic of the embryonic nucleus, which forms early in development. These sutures result from the arrangement of primary lens fibers during the fetal stage. The Y-formation helps in maintaining lens transparency.
- 14. The youngest lens fibers are present in:
- A. Central core of the lens nucleus
- B. Outer layer of the nucleus
- C. Deeper layer of the cortex
- D. Superficial layer of the cortex
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Ans: D. Superficial layer of the cortex
The youngest lens fibers are found in the superficial layer of the cortex, as the lens fibers are added from the outside inwards. With age, older fibers are pushed towards the center, forming the nucleus, while new fibers continuously add to the outermost layers.
- 15. Schwalbe’s line forming part of the angle of anterior chamber is the prominent end of:
- A. Sclera
- B. Descemet’s membrane of cornea
- C. Anterior limit of trabecular meshwork
- D. Posterior limit of trabecular meshwork
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Ans: B. Descemet’s membrane of cornea
Schwalbe’s line is the termination of Descemet’s membrane at the periphery of the cornea. It is an important landmark in the anatomy of the anterior chamber angle, playing a role in identifying the structures involved in aqueous humor outflow.
- 16. In a normal adult person, the depth of anterior chamber In the centre is about:
- A. 2.5mm
- B. 3mm
- C. 3.5mm
- D. 4mm
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Ans: A. 2.5mm
The anterior chamber depth is typically about 2.5 mm in the center of the eye in adults. This depth is crucial for maintaining proper intraocular pressure and for the accommodation of light. Variations in this depth can be associated with conditions like glaucoma.
- 17. ……… is a sweat gland:
- A. Gland of Moll
- B. Gland of Zeis
- C. Meibomian gland
- D. All of the above
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Ans: A. Gland of Moll
The Gland of Moll is a modified sweat gland located in the eyelid margins. It secretes sweat that helps to lubricate the eyelid margins.
- 18. The layer of the cornea once destroyed does not regenerate is:
- A. Epithelium
- B. Bowman’s membrane
- C. Descemet’s membrane
- D. All of the above
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Ans: B. Bowman’s membrane
Bowman’s membrane, once destroyed, does not regenerate, which can lead to permanent scarring and vision impairment. It is an acellular layer located beneath the corneal epithelium, providing structural support.
- 19. All of the following are true about corneal Endothelium except:
- A. Cell density is about 3000 cells/mm2 at birth
- B. Corneal decompensation occurs when cell count is decreased by 50%
- C. Endothelial cells contain active pump mechanism
- D. Endothelium is best examined by specular microscopy
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Ans: B. Corneal decompensation occurs when
Corneal decompensation typically occurs when endothelial cell density falls below a critical threshold of around 500 cells/mm², not just a 50% reduction.
- 20. Adult size of the cornea is attained by the age of:
- A. 2 years
- B. 3 years
- C. 5 years
- D. 9 years
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Ans: A. 2 years
The cornea reaches its adult size by around 2 years of age, making it one of the earliest parts of the eye to achieve full growth. This rapid growth is essential for normal visual development. After this age, the cornea remains relatively stable in size.
This blog is a must-read for Optometry students and professionals preparing for the Dubai Health Authority (DHA) license exam, HAAD Exam optometry, and Ministry of Health (MOH) license exam. It features 20 meticulously crafted MCQs focused on the Anatomy and Development of the Eye or Ocular Anatomy, covering key topics such as the antero-posterior diameter of the eyeball, the vertical diameter, and the circumference and volume of an adult eyeball.
Each question is provided with detailed answers and explanations, such as the importance of the 24 mm antero-posterior diameter in influencing refractive errors, or how the vertical diameter affects the anatomical structure and function of the eye. You’ll also learn about the anterior and posterior segments of the eyeball, the significance of the crystalline lens’s size and thickness, and the role of Schwalbe’s line in the angle of the anterior chamber. Whether you’re looking for DHA MCQs online, DHA MCQs for Optometrist, DHA MCQs book, DHA MCQs PDF, DHA exam questions, DHA question paper for optometrists, MOH exam questions, MOH MCQs online, MOH question paper for optometrists, or MOH questions & answer optometry, this blog provides a rich resource that’s essential for acing your exams.
