Basics of clinical optics and their application in clinical ophthalmology. Introduction to principles of interaction of light and its travel through different media. The basic principles, objectives and methods of ophthalmic instruments are also explained.
The presentation I have made and uploaded provides you with an in-depth insight into the patterns the strabismus may take following anomalies of extraocular muscles, deformities of the orbital structures,innnervational disturbances.
The author does not assume responsibility or legal liability for any errors in the text or for the misuse or misapplication of material in this work.
No copyright infringement, or plagiarism intended.
Amrit Pokharel
Real subjective refraction in astigmatismBipin Koirala
hope it will be beneficial for the students in eye care system . please like it and share it if you think it is beneficial for your studies. It will motivate me to upload more slides ..
It describes about the procedure of Hess charting. it serves as a great tool to understand the concepts involved. Suitable for optometry course. This is not a routine procedure but an important procedure which is used in diagnosis.
This PowerPoint presentation is for Grade 10 students. I have included all the topics in this presentation. Here you can know about Light, Types of lenses, Some terms related to lens, Prism, Ray diagrams, Numerical problems related to this chapter, Laws of reflection, refraction, diseases related to eyes. I have briefly described as notes, some examples and illustrations, proper diagrams and so on.
The presentation I have made and uploaded provides you with an in-depth insight into the patterns the strabismus may take following anomalies of extraocular muscles, deformities of the orbital structures,innnervational disturbances.
The author does not assume responsibility or legal liability for any errors in the text or for the misuse or misapplication of material in this work.
No copyright infringement, or plagiarism intended.
Amrit Pokharel
Real subjective refraction in astigmatismBipin Koirala
hope it will be beneficial for the students in eye care system . please like it and share it if you think it is beneficial for your studies. It will motivate me to upload more slides ..
It describes about the procedure of Hess charting. it serves as a great tool to understand the concepts involved. Suitable for optometry course. This is not a routine procedure but an important procedure which is used in diagnosis.
This PowerPoint presentation is for Grade 10 students. I have included all the topics in this presentation. Here you can know about Light, Types of lenses, Some terms related to lens, Prism, Ray diagrams, Numerical problems related to this chapter, Laws of reflection, refraction, diseases related to eyes. I have briefly described as notes, some examples and illustrations, proper diagrams and so on.
Reflection of light
Spherical mirrors
Images formation by spherical mirrors
Representation of images formed by spherical mirrors using ray diagrams
Mirror formula and magnification
Various optical instruments have been designed, using the property of reflection and refraction. Copy the link given below and paste it in new browser window to get more information on Introduction Of Ray Optics and Optical Instruments www.askiitians.com/iit-jee-ray-optics/introduction-of-ray-optics-and-optical-instruments/
The Talk on "Strabismus" is aimed at making the understanding of strabismus easy for medical students. Professor Mazhry Explained Strabismus to a 4rth year Medical Student Undergraduate Ophthalmology informal discussion on the topic of Squint evaluation and clinical evaluation. Dr Abdullah Mazhry who is a 4th Year Medical student of Allama Iqbal medical college participated in the talk.
The talk "Chronic Issues of Dry Eyes" was delivered as a webinar series on 30 Jan 2021. Prof Dr Zia ul Mazhry was the guest speaker. The talk was followed by a lively Q&A session. This webinar was sponsored by Schaigan Pakistan with their leading dry eye treatment brand Eyelub Eye drops. Eyelube composition is as under:<br>Polyethylene Glycol 400 0.4% (lubricant), Propylene Glycol 0.3% (lubricant), Hydroxypropyl Guar (GEL FORMING MATRIX) Sodium Perborate as a disappearing preservative.
A patient education lecture explaining modern catract surgery solutions. Cataract surgery these days not only removes your glasses but can correct other preexisting errors as well. Toric and multifocal IOLs have opened new windows for visual rehabilitation after cataract surgery.
Comprehensive review of Ophthalmic Manifestations of Systemic Disorders for undergraduate medical students and general practionaers. Lecture was taken by Associate Professor Dr. Zia ul Mazhry at Central Park Medical College Lahore Pakistan.
The basic concepts about refractive errors and their corrective options are explained in this lecture. It was taken at Central Park Medical College Lahore Pakistan for fourth year medical students
Introduction to general ophthalmic evaluation and management principles. Lecture taken at Central Park Medical College Lahore Pakistan. The guidelines will be useful for General Practitioners as well.
Introduction to internal assessment criteria for ophthalmology undergraduate students. Lecture was taken at Central Park Medical College Lahore Pakistan for 4th year medical students.
Dr. Mazhry’ Surgical Video, “Inject First and Then Fixate Hydrophobic Single Piece AcrySof IOL” gets selected amongst top 11 ophthalmology videos in the world.
wins a place on American academy of Ophthalmology’s ONE net work during Global ONE Video Contest 2014.
First ever video from Pakistan to get featured on the ONE Network by American Academy of Ophthalmology.
Title:
Choosing amongst current modalities to manage Diabetic Retinopathy
At Medical Retina Clinic, Eye Department WAPDA Teaching Hospital Complex Lahore
Objective:
1. To review the current management options for DR
2. To share author’s four years follow up from Jan 2008 to Nov 2011 at Medical Retina Clinic, Eye Department WAPDA Teaching Hospital Complex Lahore.
3. Discussion on future Trends in management of DR.
Synopsis:
Diabetic retinopathy is the leading cause of new blindness in the world,
Argon LASER treatment has established itself as a gold standard in the management of DR. Intravitreal therapies in the form anti VEGF agents and steroids are also being widely used nationally and internationally. These therapies do not replace but complement each other.
Author will share his four years experience at Medical Retina clinic WAPDA hospital complex Lahore. 125 patients with DR were enrolled during this period. Treatment modalities used, included Argon Green Laser, Intravitreal Anti VEGF (Bevacizumab), Intravitreal Triamcinolone and subtenon Triamcinolone. Staging and severity of the disease as well as response to the offered therapy were the parameters used to tailor the treatment options.
Dr. Zia ul Mazhry
FRCS (Edin), FRCS (Glasgow), FCPS, CICOphth (UK)
Asstt Professor Central Park Medical College Lahore.
Consultant Eye Surgeon and Head of Eye Department
Wapda Teaching Hospital Complex
210 Feroz Pur Road Lahore.
Website: www.EyeAcuity.com
mazhry@yahoo.com
03004401151
Title:
Choosing amongst current modalities to manage Diabetic Retinopathy
At Medical Retina Clinic, Eye Department WAPDA Teaching Hospital Complex Lahore
Objective:
1. To review the current management options for DR
2. To share author’s four years follow up from Jan 2008 to Nov 2011 at Medical Retina Clinic, Eye Department WAPDA Teaching Hospital Complex Lahore.
3. Discussion on future Trends in management of DR.
Synopsis:
Diabetic retinopathy is the leading cause of new blindness in the world,
Argon LASER treatment has established itself as a gold standard in the management of DR. Intravitreal therapies in the form anti VEGF agents and steroids are also being widely used nationally and internationally. These therapies do not replace but complement each other.
Author will share his four years experience at Medical Retina clinic WAPDA hospital complex Lahore. 125 patients with DR were enrolled during this period. Treatment modalities used, included Argon Green Laser, Intravitreal Anti VEGF (Bevacizumab), Intravitreal Triamcinolone and subtenon Triamcinolone. Staging and severity of the disease as well as response to the offered therapy were the parameters used to tailor the treatment options.
Dr. Zia ul Mazhry
FRCS (Edin), FRCS (Glasgow), FCPS, CICOphth (UK)
Asstt Professor Central Park Medical College Lahore.
Consultant Eye Surgeon and Head of Eye Department
Wapda Teaching Hospital Complex
210 Feroz Pur Road Lahore.
Website: www.EyeAcuity.com
mazhry@yahoo.com
03004401151
Dark Room Procedures for undergraduates(MB,BS) in the field of Ophthalmology are explained in simple terms in this presentation. Series of lectures taken at Central Park Medical College Lahore Pakistan.
Title: Making dry eyes wet
Author: Dr. Zia ul Mazhry
FRCS (Edin), FRCS (Glasgow), FCPS, CICOphth (UK)
PURPOSE: to review current management options to treat dry eyes especially evaluation of Genteal gel and Systane eye drops as novel new combinations.
clinical outcome. RESULTS: both the agents showed higher satisfaction and better clinical outcomes as compared to other available wetting agents. CONCLUSION: Genteal eye gel and Syatane eye drops are excellent recent additions to available options to treat dry eyes symptomatically. Genteal family appears to be better tolerated as compared to Systane E/D in our experience.
Dr. Zia ul Mazhry
FRCS (Edin), FRCS (Glasgow), FCPS, CICOphth (UK)
Consultant Eye Surgeon and Head of Eye Department
Wapda hospital complex
210 Feroz Pur Road Lahore
0300 440 1151
Title Secondary posterior chamber IOL (PC IOL) Implantation-made simple
Author(s) Dr zia u Mazhry FRCS, FCPS
Abstract Objective:
1. To classify Indications and to discuss surgical planning for secondary PC IOL implantation
2. To elaborate variations of surgical procedure required to manage different situations encountered in secondary PC IOL implantation.
Synopsis:
Secondary PC IOL implantation in aphakics is an established procedure. Variation of surgical procedure are required to manage different situations. The status of posterior capsule may vary from intact to partially deficient or totally absent. Similarly the technique has to be varied from simple implantation to synechiolysis to anterior vitrectomy combined with single or double haptic trans-scleral fixation of PC IOL.This course will present simplified approach to manage secondary IOL implantation.
Presentation Instruction Course
Subspecialty ophthalmology,Cataract
Education Level advance
Course Format lecture
Target Audience general
Course Length 60 minutes
Program english
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1. Basics of Clinical optics,
ophthalmic Instruments and
eye examination
Dr. Zia-Ul-Mazhry
FCPS(Pak),
FRCS(Edin),
FRCS(Glasgow),
CIC Ophth- (UK)
Associate Professor
Head of Eye Department
Central Park Medical College &
WAPDA Teaching Hospital Complex Lahore
Pakistan.
2.
3. • For Education purpose Only
• Material Taken from Various Internet
Resources
4. Overview
• Part 1
– Pretest
• Part 2
– Clinical Optics and their ophthalmic
Significance
• Part 3
– Ophthalmic instruments and Dark Room Tests
in Ophthalmology
• Part 4
– Post Test
5. Objectives
• The students should be able to:
– Their learning needs and gains
– Understand Clinical Optics and their
ophthalmic Significance
– Use Ophthalmic instrument and perform
eye Examination
– Put it al together to Evaluate, diagnose and
investigate common ocular conditions
7. MCQ-1
• The Focal length of a lens is:
a) Inversely proportional to radius of the
lens.
b) Directly proportional to the power in
diopter.
c) Inversely proportional to power in
diopter.
d) Is not related to power to diopter.
9. MCQ-3
• Average axial length of the normal adult
eye is:
a. 18-20 mm
b. 12-14 mm
c. 16-18 mm
d. 22-24 mm
10. MCQ-4
• Clinical assessment of cataract
progression is done through
a. Snellen’s visual acuity test
b. Distant Direct ophthalmoscopy
c. Slit lamp Examination
d. all of above
11. MCQ-5
• A perimetry is used to measure:
a. Central and peripheral fields
b. Visual acuity
c. Intra ocular pressure
d. Central field only
12. MCQ-6
• Objective of distant direct ophthalmoscopy
is:
a. Scleral examination
b. Conjunctival examination
c. Examination of media opacities
d. Fundus examination
13. MCQ-7
• The image formed during direct
ophthalmoscopy is:
a. Inverted and real
b. Erect and real
c. Inverted and virtual
d. Erect and virtual
14. MCQ-8
• In the process of reflection Angle of
incidence is always:
a. Equal to angle of reflection
b. Grater than angle of reflection
c. Lesser than angle of reflection
d. None of above
15. MCQ-9
• Most of the refraction occurs at the site
of:
a. Retina
b. cornea
c. Lens
d. Aqueous humor
16. MCQ-10
• Test being
performed is used to
measure:
a. Corneal diameter
b. Lens Thickness
c. Anterior chamber Angle
d. All of above
18. Clinical Optics and their
ophthalmic Significance
• Language of Optics
• Vergence
• Reflection and Refraction
• Lenses, Mirrors, prisms and fiber optics
• Focal Length and focal power
22. Real vs. Virtual Images
• Real images are formed by mirrors or lenses
when light rays actually converge and pass
through the image.
• A real image can be projected onto a piece of
paper or a screen. If photographic film were
placed here, a photo could be created.
• Virtual images occur where light rays only
appear to have originated.
• Virtual images can’t be projected on paper,
screens, or film since the light rays do not really
converge there.
24. Language of Optics
• Focal Length and Dioptric Power
The degree of convergence or divergence of a lens is expressed in
terms of its power.
Thus power of a lens is defined as the reciprocal of its focal length.
D = 100
f(cm)
25. Lenses: Focal Length
• Like mirrors, lenses have a principal axis perpendicular to their
surface and passing through their midpoint.
• Lenses also have a vertical axis, or principal plane, through
their middle.
• They have a focal point, F, and the focal length is the distance
from the vertical axis to F.
• There is no real center of curvature, so 2F is used to denote
twice the focal length.
28. Reflection of Light
• A ray of light, the
incident ray, travels in
a medium
• When it encounters a
boundary with a
second medium, part
of the incident ray is
reflected back into the
first medium
32. Critical angle is the angle of
incidence for which the angle of
refraction becomes 90
33. Total internal reflection is an optical
phenomenon that happens when a ray of
light strikes a medium boundary at an angle
larger than the critical angle.
39. Dispersion of Light
Dispersion is the separation of light into a
spectrum by refraction.
This effect causes white light to split into it
spectrum of colors.
40. One of the most
common of these is the
rainbow, which is
caused by water
droplets dispersing
sunlight.
Dispersion-Rainbows
41. REFRACTION
• Refraction is the change in direction of a wave
due to a change in its optical medium.
Normal
Lighter Medium
Denser Medium
43. REFRACTION IN
OPHTHALMOLOGY
• The refraction test is an eye exam that
measures a person's prescription for eyeglasses
or contact lenses.
• This test is performed by an ophthalmologist
or optometrist
44. Lenses and Mirrors
Lenses
• A piece of glass
material, used to
converge or diverge
transmitted light and
form optical images.
Mirrors
• A surface that
reflects light without
diffusion.
45. Concave and Convex Mirrors
Concave mirrors reflect
light from their inner
surface, like the inside
of a spoon.
• Convex mirrors
reflect light from their
outer surface, like the
outside of a spoon.
47. Lens
• A transparent material that is has at least
one curved side
• Refracts light in a predictable and useful
way
48. Types of Lenses
Converging Lens
• makes parallel light rays
come together
• Also known as convex
lens
• Thicker at the center,
thinner at the edges
49. Types of Lenses
Diverging Lens
• makes parallel light rays
move apart
• Also known as concave
lens
• Thinner in the center,
thicker at the edges
50. Lens Function
• Change the appearance of
objects (image appears
larger, smaller, upside down
or misshapen)
• Magnify images
• Project images onto a
screen
51. Terminology
• Optical Centre (O) – centre of the lens; also the
point where the principal axis crosses
• Axis of Symmetry – an imaginary vertical line
drawn through the optical center of a lens;
perpendicular to principal axis
Optical
Centre (O)
52. Focal Point
• Since lenses have 2 sides, they have a focal point
on each side.
• The principal focus is where the light rays converge
• A converging and diverging mirror has the principal
focus on different sides of the lens
53. Focal Point – Converging Lens
• Principal focus is on the opposite side of the lens
as the incident rays
Principal FocusSecondary
Principal Focus
54. Focal Point – Diverging Lens
• Principal focus is on the same side of the lens
as the incident rays
• The focal point is virtual
55. Focal Length
• Focal length (f) is the distance between the
principal focus and optical centre
• Distance from F to O, F to 2F, F’ to O, F’ to 2F
are all equal.
• 2F and 2F’ are twice the distance away from the
optical centre than the focus points.
FF’ 2F2F’ O
56. Terminology
Principal Focus (F)
• A point on the principal axis where the light rays that are traveling
parallel to the principal axis appear to converge
• In a converging lens it is on the opposite side as the incident rays
• In a diverging lens it on the same side as the incident rays
Secondary Principal Focus (F’)
• Focus that is on the opposite side as the principal focus, located the
same distance from the lens as F
• In a converging lens it is on the same side as the incident rays
• In a diverging lens it is on the opposite side as the incident rays
Focal Length (f)
• distance from the principal focus to the axis of symmetry
• Focal length is the same distance with the secondary principal focus
57.
58. Light Rays with a Converging Lens
1. A light ray parallel to the principal axis will
refract through the principal focus (F).
2. A light ray passing through the secondary
principal focus (F’) will refract parallel to
the principal axis.
3. A light ray through the optical centre (O)
will keep travelling in the same direction
without being refracted.
59. Light Rays with a Converging Lens
1. A light ray parallel to the principal axis will
refract through the principal focus (F).
60. Light Rays with a Converging Lens
1. A light ray parallel to the principal axis will
refract through the principal focus (F).
FF’
61. Light Rays with a Converging Lens
1. A light ray parallel to the principal axis will
refract through the principal focus (F).
2. A light ray passing through the secondary
principal focus (F’) will refract parallel to
the principal axis.
62. Light Rays with a Converging Lens
2. A light ray passing through the secondary
principal focus (F’) will refract parallel to
the principal axis.
FF’
63. Light Rays with a Converging Lens
1. A light ray parallel to the principal axis will
refract through the principal focus (F).
2. A light ray passing through the secondary
principal focus (F’) will refract parallel to
the principal axis.
3. A light ray through the optical centre (O)
will keep travelling in the same direction
without being refracted.
64. Light Rays with a Converging Lens
3. A light ray through the optical centre (O)
will keep travelling in the same direction
without being refracted.
FF’
65. LOCATING AN IMAGE ON A CONVERGING LENS
• What happens when object is at F’?
2F’ 2F’
66. LOCATING AN IMAGE ON A CONVERGING LENS
1. Pick a point on the object (usually the top of
the object)
2. Send any two light rays off the point on the
object.
3. Determine the refracted rays. Light rays only
refract when it hits the lens
4. Find the intersection of the light rays. If the
rays do not intersection, extend the refracted
ray until they do (exception: don’t do this for
parallel light rays)
5. Use the point of intersection to location off an
object is needed to locate its image.
67. LOCATING AN IMAGE ON A CONVERGING LENS
Ray 1 – travels parallel to the principal
axis and is refracted through the principal
focus (F)
68. LOCATING AN IMAGE ON A CONVERGING LENS
Ray 2 – travels through the optical centre
(O) and continues straight without being
refracted
69. LOCATING AN IMAGE ON A CONVERGING LENS
Ray 3 (optional since you only need 2 lines to form an intersection) –
travels through the secondary principal
focus (F’) and refracts parallel to the
principal axis
70. LOCATING AN IMAGE ON A CONVERGING LENS
Draw the image given the point of
intersection.
71. LOCATING AN IMAGE ON A CONVERGING LENS
5 Scenarios for the Object
1. Beyond 2F’: Object is greater than 2 focal
lengths from the lens (do>2f)
2. At 2F’: Object is at 2 focal lengths (do=2f)
3. Between 2F’ and F’: Object is between 1
and 2 focal lengths from the lens (f<do<2f)
4. At F’: Object is at the focal point (do=f)
5. Between F’ and lens: Object is less than 1
focal length away from the lens (0<do<f)
72. Case 1 – Object beyond 2F’
Size Attitude Location Type
Reduced Inverted
Between F
and 2F
Real
79. CONVERGING LENSES
The first lens known to be used was a converging lens called
a reading stone. Reading stones formed images that were
upright and larger than the object.
How can a converging
lens produce both
upright and inverted
images?
80. DIVERGING LENSES
• The focal point is virtual
• Thus the principal focus is on the same side
of the lens as the incident rays
81. Light Rays with a Diverging Lens
1. A light ray parallel to the principal axis will
refract through the principal focus (F).
2. A light ray passing through the secondary
principal focus (F’) will refract parallel to
the principal axis.
3. A light ray through the optical centre (O)
will keep travelling in the same direction
without being refracted.
82. Light Rays with a Diverging Lens
1. A light ray parallel to the principal axis will
refract through the principal focus (F).
F’F 2F’2F O
83. Light Rays with a Diverging Lens
2. A light ray passing through the secondary
principal focus (F’) will refract parallel to the
principal axis.
F’F 2F’2F O
84. Light Rays with a Diverging Lens
3. A light ray through the optical centre (O) will
keep travelling in the same direction without
being refracted.
F’F 2F’2F O
85. LOCATING AN IMAGE ON A DIVERGING LENS
1. Pick a point on the object (usually the top of
the object)
2. Send any two light rays off the point on the
object.
3. Determine the refracted rays. Light rays only
refract when it hits the lens
4. Find the intersection of the light rays. If the
rays do not intersection, extend the refracted
ray until they do (exception: don’t do this for
parallel light rays)
5. Use the point of intersection to location off an
object is needed to locate its image.
86. LOCATING AN IMAGE ON A DIVERGING LENS
• Q. Draw the ray diagram for this pencil to
locate its image
F’F 2F’2F O
87. LOCATING AN IMAGE ON A DIVERGING LENS
F’F 2F’2F O
Ray 1 – travels parallel to the principal axis and
is refracted through the principal focus (F)
88. LOCATING AN IMAGE ON A DIVERGING LENS
F’F 2F’2F O
Ray 2 – travels through the secondary principal
focus (F’) and refracts parallel to the principal
axis
89. LOCATING AN IMAGE ON A DIVERGING LENS
F’F 2F’2F O
Ray 3 (optional since you only need 2 lines to form an intersection)
travels through the optical centre (O) and
continues straight without being refracted
90. LOCATING AN IMAGE ON A DIVERGING LENS
F’F 2F’2F O
Size Attitude Location Type
Reduced Upright
Same side
as object
Virtual
92. Concave Lens Ray Diagrams
Ray 1 - travels from the tip of the object parallel to the
principal axis. When it emerges from the lens, it appears to
come from the principal focus (F)
93. Concave Lens Ray Diagrams
Ray 2 - travels from the tip of the object through the optical
centre of the lens and is not refracted.
94. Concave Lens Ray Diagrams
The image occurs where these rays appear to intersect.
98. Slit Lamp
• The slit-lamp
is a low-power
microscope
combined with
a high-
intensity light
source that can
be focused to
shine in a thin
beam.
99. SLE
• Observation by optical
section
• Direct diffuse illumination
• Indirect illumination
• Retro-illumination
• Scattering sclero-corneal
illumination
• Fundus observation and
gonioscopy with the slit
lamp
100. Distant Direct
Ophthalmoscopy
• Objective
– To Examine and classify media
opacities against fundal glow
• Instrumentation
– Direct Ophthalmoscope
• Methods
– Throw the light with DO at half
meter 25-50 cm distance
– Parallax Method of deviation
101. Distant Direct
Ophthalmoscopy
• Parallax Method of deviation
– Ask the patient to move his/her eye
– Opacities Moving
• With
– Anterior to nodal point
• No movement
– At or very near to nodal point
• Against Movement
– Behind the nodal point
104. Principle of Direct
Ophthalmoscopy
• If patient and observer are both
emmetropic, rays emanating from a
point in the patient's fundus will emerge
as a parallel beam and will be focused
on the observer's retina.
107. Examination Technique
• dim the lights.
• ask the patient
to fixate on a
distant target.
• approach the
patient from
the side.
• examine the
optic nerve and
surrounding
retina.
108. Direct Ophthalmoscopy:
Basic skills
• Proper position for
central fundus viewing
• Right eye to right eye
• Left eye to left eye
• Don’t rub noses…
115. Direct Ophthalmoscopy
• Advantages
– Portable
– Easy to use
– Upright image
– Magnification 15x
– Can use w/o dilation
• Disadvantages
– Small field of view
– Lack of stereopsis
– Media opacities can degrade
image
116. Indirect Ophthalmoscopy
• Monocular or binocular
• Advantages:
– Wide field of view
– Binocular instruments
provide stereopsis
• Disadvantages:
– Requires more skill
– Decreased magnification
(3x)
– Requires dilation
– Inverted image
117. Indirect Ophthalmoscopy principle
• The principle of indirect
ophthalmoscopy is to
make
• the eye myopic by
placing a strong convex
lens in front
• of it. This forms a real
inverted image of the
fundus in
• the air between the lens
and the observer.
118. Fig. 5. Limited field of
view in the direct
method. Peripheral
pencils of light do not
reach the observer's
pupil.
Fig. 6. Extended field
of view in the indirect
method. The
ophthalmoscopy lens
redirects peripheral
pencils of light toward
the observer.
127. Retinoscopy
• Objective
– To determine refractve status of the eye
• Instrumentation
– Retinoscope
– Trial Lens set
– Trial frame
128. Retinoscopy
• Methods
– Ask the patient to fixate on a distant target
– Half to 1 meter distance
– Project the streak on pupil
– Move the streak and observe the movement
of red reflex
130. Retinoscopy
• Insert +1 D Lens in front of the eye
while working at 1 meter
– No movement
• Emetropia
– With movement
• Hyperopia
– Against movement
• Myopia of < 1 D
146. MCQ-1
• The Focal length of a lens is:
a) Inversely proportional to radius of the
lens.
b) Directly proportional to the power in
diopter.
c) Inversely proportional to power in
diopter.
d) Is not related to power to diopter.
148. MCQ-3
• Average axial length of the normal adult
eye is:
a. 18-20 mm
b. 12-14 mm
c. 16-18 mm
d. 22-24 mm
149. MCQ-4
• Clinical assessment of cataract
progression is done through
a. Snellen’s visual acuity test
b. Distant Direct ophthalmoscopy
c. Slit lamp Examination
d. all of above
150. MCQ-5
• A perimetry is used to measure:
a. Central and peripheral fields
b. Visual acuity
c. Intra ocular pressure
d. Central field only
151. MCQ-6
• Objective of distant direct ophthalmoscopy
is:
a. Scleral examination
b. Conjunctival examination
c. Examination of media opacities
d. Fundus examination
152. MCQ-7
• The image formed during direct
ophthalmoscopy is:
a. Inverted and real
b. Erect and real
c. Inverted and virtual
d. Erect and virtual
153. MCQ-8
• In the process of reflection Angle of
incidence is always:
a. Equal to angle of reflection
b. Grater than angle of reflection
c. Lesser than angle of reflection
d. None of above
154. MCQ-9
• Most of the refraction occurs at the site
of:
a. Retina
b. cornea
c. Lens
d. Aqueous humor
155. MCQ-10
• Test being
performed is used to
measure:
a. Corneal diameter
b. Lens Thickness
c. Anterior chamber Angle
d. All of above
156. • Thank you
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