•The Eyeball consists of 3 layers, the outer sclera and transparent cornea, The middle
consist of the iris, choroid, and cilliary body. The inner most the retina. The anterior
chamber lies between the iris and posterior surface of the cornea. The posterior chamber
lies between the anterior surface of the lens and posterior surface of the iris. These
chambers are filled with aqueous humor secreted by ciliary's body. The space between
posterior lens and retina filled with vitreous gel. For light to reach the retina it passes
through the cornea, aqueous humor, lens and vitreous. All of these structures help focus
light onto retina, they must remain clear for light to reach the retina and stimulate
•The cornea is transparent and it is the first structure light passes through. It is
responsible for light refraction needed for clear vision.
•The aqueous humor is a clear watery fluid which fills the anterior and posterior
chambers of the anterior eye. It is produced by the cilliary process and passes through the
pupil from the posterior chamber to anterior chamber. It drains through the trabecular
meshwork located in an angle formed by cornea and iris into canal of Schlemm. This
circular canal moves fluid into scleral veins which enters circulation of body .
•Theaqueous humor baths and nourishes the lens and endothelium of the cornea. Excess
production or decreased outflow can increase intraocular pressure above the normal 10-
21 mm Hg. (glaucoma).
•Lens- it is biconvex (rounded raised area on two sides)and it is located behind the iris
and it is supported in place by small fibers called zonules. The lens bends light rays
allowing rays to fall on retina. The shape of the lens is modified by the action of the
zonules as a part of accommodation, which allows a person to focus on near objects e.g.
reading. If the clarity of the lens is altered light transmission will be affected.
•Vitreous Humor – located in the posterior cavity, behind the lens in front of the retina.
•Light passing through the vitreous may be blocked by any non transparent substance
within it. The vision varies depending on amount, type and location of the substance
blocking the light, e.g.. Bleeding into vitreous little light reaches the retina, severely
compromising vision. However cellular debris which is normal, it accumulates from cell
metabolism (floaters) cause only a small shadow. As you age the vitreous becomes more
Anatomy of Eye
•IRIS- color part of eye, it has a small round opening in the center, called pupil, which
allows light to enter the eye. The pupil constricts via action of iris sphincter muscle
innervated by CNIII, and dilates by iris dilator muscle innervated by CNV, to control the
amount of light entering eye.
•Lens- is biconvex, avascular, transparent, located behind the iris. Supported by anterior
and posterior cilliary zonules. It is composed of a thick gelatinous material enclosed in a
clear capsule. It bends light rays so they go on the retina.
•Cilliary Body- lies parallel to sclera, composed of muscle surrounding lens.
•Choroid- It is a highly vascular structure that nourishes the cilliary body, the iris and
outer portion of retina. Extends from where optic nerve enters the eye to cilliary body .
•Retina- innermost layer of the eye. It extends and forms optic nerve. Neurons make up
most of the eye that is why if it is cells are destroyed it can not regenerate. It lies inside
the eyeball. It converts images into a form the brain can understand and process as a
vision. It is composed of 2 types of photoreceptors cells, Rods, and Cones.
•Rods are stimulated in dim or darkened environments, and cones are receptive to colors
in bright environments. The retina center is called fovea centralis, composed of cones,
this area provides the sharpest visual acuity. Surrounding the fovea is the macula, has a
high concentration of cones and is free of blood vessels. The macula is nourished by
choroid and underlying pigment epithelium. The retina is surrounded by retinal arterioles
and veins. The blood supply enters the eye through optic disc located nasally. The optic
disc is where the CNII exits the eyeball. Within the disc is the physiologic cup, a
depression that is seen with opthalmoscope.
•Eyebrows, eyelids, eyelashes- they protect the eye. They provide a physical barrier to
dust and foreign particles. There is also the bony orbit and fat pads,below, and behind
eyeball, protecting eye. The upper and lower lid join at the medial and lateral canthi. The
upper lid blinks continuously, blinking distributes tears over the anterior eye surface, and
helps control light entering eye. Eyelids innervated by CN VII.
•Conjunctiva- transparent mucous membrane, cover inner surface of eyelids, the palpebral
conjunctiva extending over sclera , bulbar conjunctiva, forming a pocket under each lid
Color is pink. Glands in conjunctiva, secrete mucus and tears.
•Sclera- composed of collagen fiber meshed together, formong an opague substance
(white of eye). Makes up most of external eye and encircles the globe joining the cornea
at the limbus. It is tough and helps protect intraocular structures.
•Cornea- transparent avascular makes up anterior globe, allows light to enter. It refracts
light to focus on retina.
•Lacrimal apparatus- consists of glands and ducts, canals and puncta production of tears
•Extraocular muscles- each eye moved by three pairs , superior & inferior rectus muslces,
medial and lat rectus muscle, superior and inferior oblique
•Neuromuscular coordination produces movement of the eye in same direction(conjugate
•Refractive Errors- refraction is the ability of the eye to bend light rays so that they fall
on the retina. When light rays do not focus on the retina properly it is called a refractive
Myopia- person can see near objects clearly (nearsightedness), but distant objects
are blurred. This occurs when the image is focused in front of the retina. Either
because the eye is too short or there is too much refractive power.They use a
concave lens is used to correct the refraction.
Hyperopia- person can see distant objects clearly (farsightedness), close objects
are blurred. This occurs when the image is focused behind the retina, because the
eye is too short or the refractive power is inadequate. A convex lens is used to
Astigmatism- caused by an unevenness in the cornea or lens curvature, causing
horizontal and vertical rays to focus at two different points on the retina, resulting
in visual distortion.
Presbyopia- a form of farsightedness, that occurs as a result of the aging process
The lens ages and become less elastic,it loses it’s refractive powers and the eye
can no longer accommodate for near vision.
Once the image travels through the refractive media, it is focused on the retina,
inverted and reversed left to right. Example. If the object visualized is in the
upper part of the left temporal visual field , it will be focused in the lower part of
the nasal retina, upside down and and as a mirror image . From the retina the
image travels through the optic nerve to the optic chiasm, where the the nasal
fibers of each eye crosses over to the other side. Fibers from the left field of both
eyes form the left optic tract and travel to the left occipital cortex. Fibers from the
right field of both eyes form the right optic tract and travel to the right occipital
•Assessment interview what are the complaints by the person.
•Assessment of PMH (HTN, DM, Cancer, STD, AIDS, MS, Thyroid, etc.), Meds, OTC
(some cold meds. Contain a form of epinephrine,which dilates pupil), antihistamines
cause dryness, steroids contribute to development of glaucoma and cataracts, B-
adrenergic for HTN, can be potentiated by B-adrenergic blockers to treat glaucoma.
•Assessment of nutrition- intake of Vit. C & E, and trace minerals may prevent or delay
retinal damage, zinc deficiency related to erythematous scales in periorbital area.
•Assessment of elimination patterns – straining, valsalva maneuver can increase
•Assessment of visual fields- person covers one eye you cover opposite eye , you are 18
inches in front of the person, ask the person to follow your finger checking all visual
fields they should see the object at the same time you see it.
•Snellen chart, 20/100 bottom number is what a normal person can see at 100 feet , the
top is the distance that the person has to be at to read line.
•Assess six cardinal fields, have patient follow pen through each field and return to center
•Pupil assessment – constriction, convergence, accommodation
•Examine internal structure of eye with ophthalmoscope.
•Tono-pen tonometry- use of special probe, patient’s corneal surface anesthetized, a
covered end of probe gently touched cornea several times to obtain several readings of
intraocular pressure. Normal readings 10-22 mmHg
•Schiotz tonometer- noncontact measures time required to flatten cornea with a puff of
air, measures intraocular pressure. No anesthesia needed.
•One elevated reading does not constitute glaucoma, variations in pressure occurs
throughout the day.
•Gonioscopy-use an instrument to measure the depth of the anterior chamber.
Differentiates open angle from angle- closure glaucoma.
•Slit lamp microscopy a slit beam illuminates ocular structures, examiner looks through
magnifying lens to assess various structures.
•US (a scan probe placed against anesthetized cornea, used after cataract surgery), can do
external probe against closed eyelid to detect other pathology ( detached retina, tumors
Extraocular Cardinal gaze
•Fluorescein angiography- use a nonradioactive & noniodine dye injected IV into a
peripheral vein, followed by serial photographs for a 10 minute period of the retina
through dilated pupils provides information about blood flow. Used for DM.
•Schirmer tear test- measures tear volume produced throughout a fixed time period. Use a
strip of filter paper placed in lower lid, measured after 5 minutes.
•It is an opacity within the crystalline lens. It may be in one or both eyes. It is the third
leading cause of preventable blindness. Most are age related (senile cataract) usually over
age 65, other causes blunt trauma, or congenital factors such as maternal rubella, long
term exposure to UV light, long term use of steroids, DM. Cigarette smoking &heavy
alcohol consumption are associated with early cataract development. Many people may
have some degree of cataract, but all may not have impaired vision.
•Patho- It is usually a result of the aging process, as the lens ages, it’s fibers and protein
change and degenerate, losing it’s clarity. It usually begins at the periphery of the lens,
gradually spreading to the central portion. Over time the entire lens become opague.
When only a part of the lens affected it is called immature.
Decreased visual acuity affecting both close and distance, light rays are scattered as they
pass through the lens so they complain of a glare, because of the glare they have
difficulty adjusting between light and dark environments. They have difficulty
distinguishing colors, The pupil may appear cloudy grey or white rather than black,
Based on visual acuity and complaints of visual dysfunction, the opacity is directly
observable by slit lamp , or opthalmoscopic exam, the pupilmay appear white, US.
Management- non surgical- The person usually changes their glasses until that no longer
works, use of magnifiers to increase close vision, the glare makes night driving difficult
so they drive in the day, surgery indicated when vision and ADL is affected.
Surgical- Only one eye at a time will be done, an artificial lens may be used to replace the
one removed, it is implanted during surgery, all corneal curves anterior eye diameter
done before surgery. Surgery is usually done as outpatient, using local anesthetic, if
general used kept in hospital overnight.
•Using a microscope they make a small incision at the edge of the cornea and remove the
lens either with a forcep or a supercooled probe (cryoextraction), or emulcification (use
ultrasound vibration to break lens material into fragments which is then suctioned out. If
the entire lens and surrounding capsule is removed it is called intracapsular extraction.
•Extracapsular extraction is most common, they remove the nucleus and cortex of the
lens, leaving posterior capsule intact. The remaining capsule supports the lens implant
and protects the retina, also this procedure requires a smaller incision. The implant is
polymethylmethacrylate, PMMA- or Plexiglas.
•Post op- caution patient to avoid reading, lifting, strenuous activities, and sleeping on
operative side, do not disturb dressing, instill drops as ordered, follow up appt., their
visual acuity will be decreased, headache, eye pain, nausea, itching, and redness, use eye
patch or shield (usually 24 hrs),
•Is a separation of the sensory portion of the eye from the choroid, pigmented vascular
layer. It is usually precipitated by trauma, it occurs spontaneously, the vitreous humor
adheres to the retina at the optic disk, the macula and periphery of the eye. With aging the
vitreous humor shrinks and pulls the retina away from the choroid. The retina may tear
and fold back on it’s own or it remains intact but away from the choroid. A break or tear
in the retina allows fluid from the vitreous to enter the area. Fluid from vitreous , choroid
, gravity, and traction by vitreous separates the retina from the choroid. The area
increases in size increasing loss of vision, if this is not corrected the neurons of the retina
will become ischemic and die causing permanent blindness.
•Photopsia (light flashes), floaters (spots), cobweb, hairnet, or ring in the visual field,
painless loss of peripheral or central vision (like a curtain coming across field of vision),
the area of visual loss corresponds to area of detachment.
•Diagnostics – US, slit lamp, History
•Cryotherapy, using supercooled probe, laser photocoagulation causing adhesions to weld
the layers together.
• Scleral buckling- indentation or fold created in sclera, bringing choroid into contact with
retina. Contact maintained with a local implant on the sclera or an encircling strap or
•Air may be injected into vitreous cavity (pneumatic retinopexy), the person is position so
air bubble pushes the detached portion into contact with choroid.,
•No lifting, bending or straining, shield, follow up, Limit position of head following
pneumatic retinoplexy, analgesics, topical antibiotic and corticosteroids
•A condition characterized by increased intraocular pressure and gradual loss of vision. It
is called the silent thief of vision. It affects people over age 40, 25 % of people with it
goes undetected. It is the leading cause of blindness, high incidence among Afro
•Primary glaucoma is most common in age over 60, secondary glaucoma develops as a
result o infection, inflammation of eye, cataract, tumor, hemorrhage or trauma.
•Aqueous humor a thick fluid which occupies the anterior and posterior chamber of the
eye. The normal intraocular pressure 10-20 mmHg, it is maintained by a balance between
the production of aqueous humor in the ciliary body , it’s flow through the pupil from the
posterior to the anterior chamber of the eye, and it’s outflow or absorption through the
trabecular meshwork and canal of Schlemm. When the balance is disrupted usually due to
decreased outflow or absorption of aqueous humor the IOP increases causing ischemia of
the neurons of the eye and degeneration of optic nerve. The neurons begin to die at
periphery of retina, causing painless progressive narrowing of visual field. Primary
glaucoma is broken down into
•Open Angle- most common form, cause unknown, occurs most at earlier age. The
anterior chamber between the iris and cornea is normal. The flow of aqueous humor
through the trabecular meshwork and into canal of Schlemm is obstructed. Restricted
outflow leads to IOP, it is a chronic and gradually progressive.
•Manifestations- loss of peripheral vision, mild headache, diff.adapting to dark, halos
around lights, and diff. focusing on near objects. As pressure increases acuity decreases.
•ANGLE – CLOSURE GLAUCOMA
•Called narrow angle or closed angle, seen over age 35, incidence higher in older adults.
There is narrowing of anterior chamber angle, occurs because of corneal flattening or
bulging of iris into anterior chamber, when the lens thickens during accommodation and
the iris thickens during pupil dilation , this angle can close completely. This permanent
closure can block outflow of aqueous humor through the trabecular meshwork and canal
of Schlemm, IOP raises abruptly, this can damage the neurons of the retina and optic
nerve, leading to permanent loss of vision. It is usually unilateral. Because of the effects
of pupil dilation on aqueous outflow in angle closure glaucoma, episodes occur in
darkness, emotional upset, or other factors that cause the pupil to dilate. Patients may
have intermittent episodes which last several hours, before a prolong attack occurs. Avoid
medications such as Atropine and other anticholinergics which have a mydriatic (pupil
•Manifestations- Severe eye and face pain, general malaise, N/V, seeing colored halos
around lights, abrupt decrease in visual acuity, reddened eye and clouded cornea &
corneal edema, fixed pupil.
•Tonometry, Fundoscopy, Gonioscopy, visual field testing
•Cholinergics (miotics) - Pilocarpine, Carbachol, cause contraction of sphincter of the
iris, constricting the pupil, and contraction of the ciliary muscle that promotes
accommodation for near vision. It allows aqueous humor outflow by increasing drainage
through trabecular meshwork in open angle. In closed angle pupillary constriction flattens
the iris, opening angle, and canal of Schlemm.
•Given by drops
•Adrenergic agonists (mydriatics), - epinephrine and dipivefrin given with miotics to
counteract the effects of miotic on accommodation,. They decrease production of
aqueous humor by cilliary body, thereby decreasing IOP
•Beta Adrenergic blocking agents Timolol (timoptic), decrease production of aqueous
humor in ciliary body, longer half life requiring less frequency, causes systemic effects
like other beta blockers ( broncho spasm, bradycardia heart failure)
•Carbonic Anhydrase inhibitor Dorzolamide (trusopt), decreases production of aqueous
humor lowering IOP, used with other drugs to control pressure when beta blockers are
contraindicated. Acetazolamide (diamox), systemic carbonic anhydrase inhibitor.
Monitor weight and lytes, administer in morning to avoid interrupted sleep because of
diuretic effect. Encourage fluids, get up slowly orthostatic hypotension.
•Prostaglandins Analogs newer class- Latanoprost (Xalatan), increase aqueous outflow.
Long acting requiring once a day
•In acute angle closure diuretics may be given IV, for rapid response of decreasing IOP.
Both carbonic anhydrase Diamox and osmotic diuretic Mannitol are used
•Administer pilocarpine at bedtime it blurs vision
•Ocusert pilo place in conjunctival sac under upper lid given once a week, causes brow
pain and increased tearing and headache
•After instilling drops squeeze bridge of nose gently prevent systemic absorption. Keep
eyes closed for 1-2 min, after administration.
•Open angle – Trabeculoplasty and trabeculectomy filtration - improves drainage from
anterior chamber. In laser Trabeculoplasty multiple laser burns created around trabecular
meshwork, as the burns heal the scars create tension stretching and opening meshwork.
Non invasive use gonioscope.
•Trabeculectomy is a filtration method where a permanent fistula is created to drain
aqueous, from anterior chamber. Part of meshwork removed, and a flap of sclera is left,
creating fistula between anterior chamber and subconjunctival space. Aqueous drains into
space under conjunctiva so it can be absorbed into circ. Done under anesthesia.
•Acute angle closure- Laser iridotomy non invasive use of a laser creating small
perforations in iris (small segment removed) allowing aqueous to drain from posterior
chamber to anterior and out through meshwork, and canal of Schlemm.