Introduction to ophthalmology for dental students

2. Why should Dentists study
Ophthalmology ?

5. Why should a dentist study Ophthalmology?
Because the eyes and teeth are closely related and
interacting:
1. Both are highly specialized organs.
2. Embryological link (Ectoderm).
3. Neurological link (Trigeminal nerve and Facial nerve).
4. Diseases or syndromes affect both organs.
5. Dental diseases can lead to eye diseases.
6. Importance of eye protection for both the dentist and
the patient.

6.  Eye and teeth are highly
specialized organs of the body.

7.  Eye and teeth are highly
specialized organs of the body.
The human eye
is a highly specialized sense
organ capable of receiving visual
images (retina), which are then
carried to the brain (optic nerve).

8.  Eye and teeth are highly
specialized organs of the body.
The human eye
is a highly specialized sense
organ capable of receiving visual
images (retina), which are then
carried to the brain (optic nerve).
The dental pulp
is a highly specialized mesenchymal
tissue with a restrict regeneration
capacity.
Enamel is the hardest and most highly
mineralized substance of the body.

9. Embryological Link
The three germ layers

10. Embryological Link
 forms the lens, corneal
epithelium & eyelids.
 together with the
ectomesenchyme of the neural
crest  the tooth germ 
organized into three parts:
• the enamel organ,
• the dental papilla and
• the dental sac or follicle.

11. Neurological Link
Trigeminal n. (5th cranial nerve):
Facial n. (7th cranial nerve)

12. Neurological Link
Trigeminal n. (5th CN):
1. Sensory: innervate the skin, mucous membranes and
sinuses of the face.
2. Motor: Only the mandibular branch of CN V has motor
fibers. It innervates the muscles of mastication.
3. Parasympathetic Supply: The post-ganglionic neurons
of parasympathetic ganglia travel with branches of the
trigeminal nerve.
(But note that CN V is NOT part of the cranial outflow of
PNS supply)

13. Neurological Link
Facial n. (7th CN):
1. Motor – muscles of facial expression….etc
2. Sensory – a small area around the external ear.
3. Special Sensory – provides special taste
sensation to the anterior 2/3 of the tongue
4. Parasympathetic – supplies many of the glands
of the head and neck, including:
 Submandibular and sublingual salivary glands.
 Nasal, palatine and pharyngeal mucous glands.
 Lacrimal glands.

16. Treponema Pallidum

19. Dentinogenesis imperfecta in Osteogenesis imperfecta

21. Importance of Eye
protection
For both
 The dentist and
 The patient

22. Importance of Eye
protection
 Risk of ocular contusions
(blunt trauma) and cuts
from clamps and sharp
instruments.
 Risk of trauma by particles
projected by equipment that
can produce a velocity of up
to 50 mph (= 80.46 K/h).

23. Importance of Eye
protection
 Conjunctivitis linked to waterline
contaminants. This can include
adenovirus and herpes simplex.
 Microbial infections from
contaminated handpiece cooling
mists and ultrasonic/air polishing
units.
 Electromagnetic radiation from
lasers and damage from UV
rays from curing lights.

24. Personal Protective Equipments (PPEs)

25. Standard Sterilization of Dental
Instruments

26. Standard Sterilization of Dental
Instruments

27.  Anatomy

28. The skull is divided into two parts
The Cranium
(= Neuro-Cranium)
The Facial Skeleton
(= Viscero-Cranium)
The
Cranium
can
be
divided
into
Cranial
Base
Cranial
Vault

29. The Orbits

30. The orbital cavities are a pair of large bony sockets that
contain the eyeballs and their associated structures.

31. Cranium
Facial
Skeleton
The two orbital cavities are parts of the facial
skeleton and separate it from the cranium.

32. Quadrilateral pyramid

33. .
.

35. 7 Bones form the orbital cavity

36. This view of the skull shows 6
bones,
 missing the palatine bone.

38. The following seven bones form the orbit:
1. Sphenoid.
2. Frontal.
3. Zygomatic.
4. Ethmoid.
5. Lacrimal.
6. Maxilla.
7. Palatine.

39. The following seven bones form the orbit:
1. Sphenoid.
2. Frontal.
3. Zygomatic.
4. Ethmoid.
5. Lacrimal.
6. Maxilla.
7. Palatine.

40. The following seven bones form the orbit:
1. Sphenoid is the most important bone.
2. Frontal.
3. Zygomatic.
4. Ethmoid.
5. Lacrimal.
6. Maxilla.
7. Palatine.
Why ?
Because it contains the two most
important openings of the orbit;
 the optic canal.
 the superior orbital fissure.

41. Orbital walls: 4 walls
1. Roof
2. Floor
3. Medial wall
4. Lateral wall
Which is the longest ?
Which is the shortest ?
Which is the weakest ?
Which is the strongest ?
 the medial wall.
 the floor.
 the medial wall.
 the lateral wall.

54.  Outer protective
layer of the
eye-globe
(Cornea and
sclera)

55.  Middle
nourishment
layer of the
eye-globe
(Choroid,
Ciliary body
and Iris)

56.  Inner sensory
layer of the
eye-globe
(Neurosensory
retina)

57.  Inner sensory
layer of the
eye-globe
(Neurosensory
retina)

62. The lacrimal system is made up of
 a secretory system, which produces
tears, and
 an excretory system, which drains the
tears.

66. Exposure of the palpebral portion of the right lacrimal gland

67. The punctum is the start opening of the
excretory system

70.  Each punctum leads to a canaliculus
 Both canaliculi join at the common canaliculus to enter the
lacrimal sac.

73. The eyelids
Definition:
are movable thin curtains of skin,
muscle, fibrous tissue, and mucous
membrane that cover the eye and
meet at the canthi.

74. Gross anatomy
Interpalpebral fissure
It is the elliptical opening separating
the eyelids.
Usually 30 mm wide and 10 mm high
(slightly higher in females).

75. Gross anatomy
The resting position of eyelids: (in 1ry position)
 The upper lid covers the upper 1/6th of
the cornea, 2mm below superior limbus
(higher in children).
 The lower lid position is level with, or
just above, the inferior limbus.

76. Left eyelid ptosis

78. Orbicularis Oculi muscle

79. Levator palpebrae superioris
upper and lower tarsi (tarsus)
Orbital septum