EYE AND VISION DISORDERS MIDTERMS Anatomy of The Eye

EYE AND VISION DISORDERS Layers of the Eye
MIDTERMS Sclera
 Outermost layer
Anatomy of The Eye  White avascular dense fibrou
EYEBALL  Helps maintain the shape of t
 Sits in the orbit contents
 Moved through all fields of gaze by the extraocular muscles
innervated by CN II, IV, and VI Choroid
CV III = involves in size of pupil  Middle vascular layer
 Helps give supply of blood
CORNEA structures of the eye
 Transparent avascular *attached to ciliary muscle = l
domelike structure that
forms the anterior most Retina
portion of the eyeball  Composed of neural tissue
 Main refracting surface of nerve
the eye  Landmarks:
 Contains high concentration o Optic disc: point of en
of nerve fibers  Pink, oval or c
REFRACTION = bending of light o Retinal vessels
o Macula: responsible fo
IRIS
 Surrounds the pupil Chambers of The Eye
 Highly vascularized pigmented collection of fibers Anterior Chamber:
 Contains dilator and sphincter muscles which controls pupil size  Aqueous – filled
o Dilator muscles are controlled by the sympathetic  Lies between the
nervous system (everything is high and dry except) posterior cornea and
o Sphincter muscles are controlled by the anterior iris and pupil
parasympathetic nervous system
LENS Posterior Chamber
 located behind iris and pupil  Aqueous – filled
 avascular and transparent biconvex structure  Lies between the
 enables focusing for near and distant vision through posterior iris and pupil
accommodation and anterior lens
 involves refraction of light (bending of light) Anterior lens =
focal length aqueous humor is
focuses light rays directly on the retina produced

VISION MECHANISM Vitreous Chamber
 Contains the gelatinous vitreo
 Largest chamber in the ocula


Humors of The Eye
Aqueous Humor
 Transparent nutrient- filled flu
 Produced by the posterior ch
 Production influences intraoc
o Normal IOP range = 1

Vitreous Humor
 Mostly water
 Helps maintain the shape of


ERRORS OF R
 Vision is impaired because
prevents light rays from focus
 Main symptom is blurred vis
Distant Objects  Emmetropia: a normal refracti
 to focus on objects in on retina with no optical defec
distance, the ciliary
muscles relax and the lens MYOPIA
flatten and thins. Light rays

, ASTIGMATISM
 Cause: irregular corneal curve Medical Management:
 Irregularity causes the GOAL: maintain a safe level of IOP
incoming light to be bent  Pilocarpine; Carbachol
unequally o Cholinergic agents (m
o MOA: opens the trabe
Clinical Manifestations: pupils allowing increas
 Headaches o S/E: difficulty seeing in
 Distorted vision/ Blurred vision *Miotics = pupil constr
 Eye strain  Acetazolamide (Diamox)
 Squinting o Carbonic Anhydrase I
 Difficulty driving at night o MOA: decreases aque
o S/E: GI upset, impoten
Management:  Timolol
 Prescription eyeglasses o Beta – blocker
 LASIK (Laser – assisted in situ keratomileusis) o MOA: decreases aque
o S/E: bradycardia, hyp
LASIK **If not increased level of IOP is not
 Surgical procedure optic nerve, thereby causing blindnes
 Low to moderate amounts of
myopia or hyperopia, with or Laser Management
without astigmatism Laser trabeculoplasty:
- A laser beam is applied to t
Photorefractive keratectomy (PRK) surface of the trabecular mes
 Indications open the intratrabecular spa
o Low to moderate amounts widen the canal of S
of myopia or hyperopia, promoting outflow of aqueou
with or without and decreasing IOP.
astigmatism
o Insufficient corneal Indications:
thickness - Open-angle glaucoma
adequately controlled on
GLAUCOMA tolerated medical therapy
 A group of ocular condition characterized by elevated IOP - Open-angle glaucoma in
 Common among people older than 40 years’ old which compliance with
 No cure but treatable therapy is less than optim
practical, social, or e
reasons or if the medical
effect profile is co
unfavorable for the patien
- Open-angle glaucoma i
medical treatment as initia

Surgical Treatment
Trabeculectomy:
 Surgical creation of an openin
fistula in the trabecular mesh
to drain aqueous humor from
anterior chamber to
subconjunctival space
*Progressive eye disorder  GOAL: create the right amou
*IOP: influenced by the production of aqueous humor flow without causing overfiltra

Aqueous Humor is produced in the Indications:
ciliary body. From the posterior  POAG
chamber, the aqueous humor  PCAG unresponsive to iridoto
enters the anterior chamber through  Childhood glaucomas
the pupil and drains through the
trabecular meshwork into the canal
of Schlemm, normal flow depends
on the intact drainage system and an Primary Closed Angle Glaucom
open angle (45 - degree).  reduction in the outflow
aqueous humor resulting

angle closure