Lens and Cataract Flashcards
The lens is suspended by a thin filament of zonules from the ___ to the ___ anteriorly and ___ posteriorly
ciliary body, iris, vitreous
Back area is the most important area which contains the retina and its ____
photoreceptors
Outer part and engulfs the whole lens structure
Elastic membrane containing the cortex nucleus.
Lens capsule
Middle part of lens
Cortex
Central part of Lens
Nucleus
Thin filamentous fibers mainly hold the lens in place
attaching it to the ciliary body
Suspensory zonules of Zinn
The Lens capsule is line by ___________ and they continuously
produce lens fibers that is why the lens continuously increase in size, length,
and weight through the years
epithelial cells anteriorly
Function of lens
Refraction and Accommodation
To focus the light exactly at the retina
Bending of light rays that passes through one medium to another
refractive medium
Refraction
Physiologic interplay of the ciliary body, zonule and lens that results in focusing of near objects upon the retina.
Accommodation
The muscles are relaxed, the zonules are taut, and the lens as a whole is flat.
No accommodation,
The ciliary body contracts, zonules relax, and the lens assumes a more globular formation
There is accommodation
4 types of errors of refraction
Myopyia
Hyperopia
Presbyopia
Astigmatism
Term used for a normal refractive index
Emmetropia
Physiologic error
Loss of accommodation due to aging
Inability to read fine print or discriminate fine close objects to about age 40
Presbyopia
Irregular vision
Astigmatism
Nearsightedness
Myopia
Farsightedness
Hyperopia
Diopter in lens of Adolescents
12-16 D
Diopter in lens of 40 yrs old
4-8 D
Diopter in lens of >50 yrs old
<2 D
Treatment of Presbyopia
Corrected by plus lenses
Inability to perform near tasks
• Accommodation starts to fail, lens loses its ability to resolve, separate,
distinguish, and refract the light rays causing blurring of vision.
• Due to irregular refraction within the lens, they may have multiple
images, stardust, or difficulty of driving at night.
Presbyopic Symptoms
Most common cause of loss of lens transparency (Overall)
Age related
Most common cause of loss of lens transparency/ blindness by metabolic disorder
Diabetes
Blurring of vision, glare, second sight and color discrimination
Trauma, drug related, systemic, or metabolic such as diabetes
With lens becoming more yellow to brown in color, objects appear darker
in color that color discrimination becomes more difficult.
Loss of lens transparency
Patients will complain of decreased vision,
glare, and image distortion.
Subcapular lens opacity
Patients have increased refractive power because of a
denser nucleus, developing ?
Lenticular myopia
Lenticular myopia as progressively become more
myopic, such that they can read without the glasses they normally need in a
phenomenon called?
Second sight
Patients have increased refractive power because of a denser nucleus, developing lenticular myopia. They progressively become more
myopic, such that they can read without the glasses they normally need in a
phenomenon called second sight.
Nuclear Sclerosis
Refractive symptoms
Most likely from trauma
Dislocation
Condition where there is tremulousness in the iris or
vibration or agitated motion of the iris with eye movement
Iridodonesis
Peripheral dark reflex with central orange
red reflex
Spoke-wheel sign
Signs of dislocation
Whitish pupillary reflex
Iridodenesis
Opthalmoscopic signs: (+) central dark reflex and spoke-wheel sign
True or False
Examination of the lens is best done with dilated pupil
True
You can use Penlight/slitlamp/ophthalmoscope
Dense Cataract
You can use Slitlamp/opthalmoscope
Less dense Cataract
If the lens is dense enough such that the ophthalmoscope will
not allow for the retina and the optic nerve to be viewed, a ____ may be required.
B scan
Assessment of the red-orange reflex will assist on the
identification of ______
Posterior subcapsular cataract
Provides a magnified view of the lens to describe the type, severity, and location of the cataract.
Slit lamp
Used to evaluate the optic nerve and retina to detect the eye problems that could affect visual acuity such as macula; especially when the patient reports metamorphopsia or
difficulty with near objects.
Opthalmoscope
Any opacity of the lens
Cataract
Causes of cataract
Acquired and Childhood
Cause of Acquired Cataract
• Age related • Traumatic/Radiation • Ocular disease (uveitis, glaucoma etc) • Systemic diseases (DM very quick, etc) • Previous eye surgeries
Pathophysiology of cataract
Product of Protein denaturation and oxidative stress from subsequent hydrolysis
Decreased glutathione concentration and oxidation of methionine and cysteine
Biochemical changes in Cataract
❖ Increased sodium and insoluble protein
❖ Decreased soluble protein
❖ Bound water reflecting loss of binding sites
Classification of cataract according to opacification
Immature Intumescent Mature Hypermature After cataract
Opacity can be observed, but no opacity in between
Transparent lens fibers are present
Opacity is located centrally
Little clarity of cataract
Immature
Swelling of the lens with the presence of fluid clefts
Opacification of all lens fibers is observed
Intumescent
Whole lens homogenously opacified, appears as a
white pupil
Opacification of all lens fiber
Mature
Liquefaction of opaque lens fibers (Morgagnian)
Nucleus is not centrally located (Inferiorly)
Waited for a few months or years then becomes
liquefied to the point that the nucleus becomes
mobile
Some of the lens fibers have liquefied, with calcific
areas
Hypermature
Opacification of the posterior capsule after cataract
surgery.
Primary complication of cataract surgery
After cataract
Lens liquefaction has caused the lensnucleus to go down
Morgagnian lens
Classification of cataract according to location
Nuclear
Cortical
Posterior subscapular
Classification of cataract according to location:
Hard
Nuclear
Classification of cataract according to location:
Soft
Cortical and Posterior Subscapular
Classification of cataract according to location:
Appears gold white granules
Posterior Subscapular
Classification of cataract according to location:
Myopic shifts and better vision
Nuclear
Classification of cataract according to location:
Does not liquefy that much
Nuclear
Classification of cataract according to location:
More or the inside part
Nuclear
Classification of cataract according to location:
Opacity of lens fibers in spoke like pattern
Cortical
Classification of cataract according to location:
More of the intermediate part
Cortical
Classification of cataract according to location:
Almost always granular
Posterior Subscapular
Classification of cataract according to location:
Decreased vision disproportionate to size
Posterior Subscapular
Classification of cataract according to location:
Located in the cortex adjacent to the posterior capsule.
Always at the back
Posterior Subscapular
Classification of cataract according to location:
Common cataract of diabetes, taking steroids, radiation, trauma
Posterior Subscapular
Poor hue discrimination or mononuclear diplopia
Nuclear sclerosis
True of False
Most nuclear cataracts are bilateral but may be asymmetric
True
Earliest symptom of nuclear sclerosis
Improved near vision without glasses/ Second sight
Occurs from an increase in the refractive power of the central lens, creating a myopic (nearsighted) shift in refraction
Nuclear Sclerosis
True or False
Nuclear sclerosis is normal condensation process of the lens that occurs after middle age
True
Changes in the hydration of lens fibers creates clefts in a radial pattern
around the equatorial region
Cortical Cataract
True of False
Most cortical cataracts are bilateral and often symmetric
False (Assymetric)
Visual function is variably affected, depending on how near the opacities
are to the visual axis
Cortical Cataract
They tend to cause visual symptoms earlier in the development owing to
the involvement of the visual axis.
Posterior subscapular
Common symptom of Posterior subscapular cataract
Glare, reduced vision under bright lighting condition
True or False
Pos. subscapular cataract are painful
False
Presence of spots in the visual field
Posterior Subscapular
Contusion may produce a cataract months after the event
Traumatic cataract
Extrusion of lens material into the anterior chamber
Traumatic cataract
Rupture of the lens capsule
Traumatic cataract
Lens induced ocular disease
Phacomorphic or Phacogenic Glaucoma
Phacolytic Glaucoma
Lens induced uveitis
Lens particle Glaucoma
Rapid swelling of lens follows hydration of lens fibers in intumescent
cataract
Phacomorphic or Phacogenic Glaucoma
May follow surgical or accidental rupture of lens capsule
Phacomorphic or Phacogenic Glaucoma
In Phacomorphic or Phacogenic Glaucoma, there is an increases AP dimension of the lens causing?
Pupillary block with forward
movement of the iris
What type of glaucoma can phacomorphic or phacogenic glaucoma can cause?
May result in secondary angle closure glaucoma
Lens is really hard to the point that it disrupts the point of AC hence
creating increased pressure and provides more inflammation
Phacomorphic or Phacogenic Glaucoma
True or False
Phacomorphic or Phacogenic Glaucoma is painless
False
Main treatment for Phacomorphic or Phacogenic Glaucoma
Decrease the pressure by taking out the lens
Leakage of lens proteins from a hypermature cataract cause uveitis
Phacolytic Glaucoma
Uveitic type of inflammation but can also increase the intraocular
pressure
Phacolytic Glaucoma
Presence of macrophage plugging the trabecular meshwork
Phacolytic Glaucoma
Main treatment for Phacolytic Glaucoma
Immediate Surgery
Accidental rupture of the lens capsule
liberates lens proteins
Lens induced uveitis
True or False
Lens induced uveitis sometimes occurs with glaucoma
True
Treatment of Lens induced uveitis
Lens extraction
Corticosteroid administration
Pathognomonic of Lens induced uveitis
Mutton-fat precipitates, posterior
synechiae (adhesions) and pupillary
membranes
Following a penetrating lens injury or surgical procedure, particle of lens
cortex migrates to the anterior chamber obstructing the trabecular
meshwork
Lens particle Glaucoma
Occurs within weeks to months or years
Lens particle Glaucoma
Treatment of Lens particle Glaucoma
Lower IOP and Corticosteroid administration / surgical
removal of retained lens material
Metabolic cataracts
Diabetes Wilsons disease Mytonic dystrophy Galactosemia Hypocalcemia
Sunflower cataract
Wilsons disease
Christmas tree appearance
Mytonic dystrophy
Drug indiced/ Toxic Cataracts
Corticosteroids Anticholinesterase/Myotics Amiodarone Statins Phenothiazines
Posterior subcapsular opacification (PSC)
Corticosteroids
Anterior subcapsular opacification (ASC)
Miotics like Achtylcholinesterase
Stellate anterior axial pigment deposition
Amiodarone
2 types of childhood cataract
Acquired
Congenital
Adverse effect of Lasik
Bursting of Cornea
Lesion >2mm with visual impairment
Surgery
Surgery can prevent what disease in childhood cataract?
Amblyopia or Lazy eye
Most common childhood infection to cause congenital cataract
Rubella
Most common childhood cataract
Congenital
Most common congenital cataract
Hereditary
Lens development anomalies
Ectopia Lentis
Sherophakia
Lenticonus
Aphakia
Displacement or malposition of the eye’s crystalline lens from its normal location
Ectopia Lentis
Signs and Symptoms of Ectopia
lentis
Iridodonesis
Decreased vision
Major syndromes associated with
Ectopia Lentis
Marfan syndrome
Homocystinuria
Weill-Marchesani syndrome
Ectopia Lentis:
some zonular fibers remain attached acting as hinge (lens
subluxated from usual position)
Subluxation
Ectopia Lentis:
Loses entire support of zonular fibers
Dislocation
True or False
Subluxation in Spherophakia is uncommon
False
Increased curvature leading to Myopia
Spherophakia
Small lens with increased anterior and posterior curvatures
Spherophakia
Rare; Cone-shaped anterior pole of the crystalline lens
Lenticonus
Marked thinning of anterior lens capsule
Lenticonus
Condition where the lens is not present
Aphakia
Term who have artificial lenses
Pseudophakia
Methods of correction of Aphakia
Spectacles
Contact Lens
Intraocular lens
Lasik
Indications of cataract surgery
Lens threatens to cause secondary glaucoma or uveitis
Visual defect interferes with patient’s vocation
Permit fundus visualization to monitor glaucoma
Permit adequate visualization of the fundus for retinal/vitreous conditions
As a refractive measure
2 Techniques of Cataract Surgery
Intra-Caps. Cataract Extraction (ICCE)
Extra-caps. Cataract Extraction (ECCE)
• The entire lens is removed
• Make an incision take
everything out
Intra-Caps. Cataract Extraction (ICCE)
• Nucleus and cortex removed, capsule
is intact
Extra-caps. Cataract Extraction (ECCE)
Types of ECCE
Traditional ECCE
Manual small incision cataract
surgery (MSICS)
Phacoemulsification – UTZ
Laser assisted cataract surgery
Surgery with highest and quickest recovery rate, you can do this in 8
minutes and earn 6 figures by melting and suctioning the cataract in place
Phacoemulsification
An incision is made at the limbus either superiorly or temporally. An opening is
created in the anterior capsule (anterior capsulorhexis), and the nucleus and
cortex of the lens are removed. An intraocular lens is placed in the empty
“capsular bag” thus supported by the intact posterior capsule.
Traditional ECCE
In Traditional ECCE:
An incision is made at the limbus either ___ or ___
superiorly or temporally
In Traditional ECCE:
An opening is
created in the _____ and the nucleus and
cortex of the lens are removed.
Anterior capsule (anterior capsulorhexis), and the nucleus and cortex of the lens are removed.
Nucleus is
removed intact, using a small incision. Cortex is removed by manual aspiration.
Manual Small Incision Cataract Surgery (MSICS)
Indicated for dense cataracts unsuitable for phacoemulsification
Manual Small Incision Cataract Surgery (MSICS)
Now the most common form of ECCE in developed countries
Phacoemulsification UTZ
. Uses a handheld
ultrasonic vibrator to disintegrate the hard nucleus. Nuclear material and cortex
are aspirated via a 2.5 – 3 mm incision then insertion of foldable intraocular
lenses.
Phacoemulsification UTZ
If you correct the patient the patient can only see one
vision either far or near
Monofocal
Several focalities (far, near, immediate, at the same time)
Miltifocal
Improves your accommodation
Accommodative
Designed for people with astigmatism
Toric
Infection of the globe that leads to inflammation
End opthalmitis
Whole globe is affected, one of the most common
complication even if you did the surgery well
Panendopthalmitis
Corneal decompensation because of so much
power and heat, because the cornea has a delicate
structure
Retinal
detachment
Once you rupture the capsule the vitreous goes out, it is another factor why we keep the capsule in place
Vitreous loss
It can happen when the surgery is very long and the
pressure drops then you can have hemorrhage
Cystoid macular
edema
Cloudiness post-operatively, because of the
retained inflammatory materials (happens 2-3 years
after surgery) treated only with laser.
After cataracts
