Transcript The Aging Eye

The Aging Eye
January 5, 2004
Dorothy D. Sherwood, M.D.
Cataracts
• Cataracts are the leading cause of
blindness world wide.
• Cataract surgery is the most frequently
performed surgical procedure in the US
with 1.5 million operations annually
• 50% of those over 65 develop vision
impairing cataracts.
Cataracts
• Definition and
Symptoms of
Cataracts.
– Clouding of the lens
which prevents light
from passing through
properly to the retina
– Types -3
Cataracts
• Nuclear Cataracts
– Most common age-related cataract
• Substantial genetic component
• Age, female sex, smoking are risk factors
• More common in white
• Cortical
– Related to sun exposure
– More common in blacks
• Posterior Subcapsular
– steroids
Cataracts
• Symptoms:
– Cloudy vision, glare, halos, decreased night
vision, faded colors, double vision, need for
brighter light when reading
• Treatment – can neither be prevented or
treated with medications – surgical only
– Removal of lens and insertion of intraocular
lens (permanent)
Cataracts
• Indications for surgery
– When visual impairment interferes with ADL’s, driving,
working,
– Co-existing ocular conditions requiring removal for
treatment such as macular degeneration, diabetic
retinopathy, glaucoma
• Peri-operative evaluation- none
– 19000 cases – no improved outcome with preoperative evaluation, except MI within 3 months
– No need to stop anticoagulants or ASA-Archives –
April 28, 2003 – 163(8):901-908
Cataracts
• Peri-operative complications
– Hypertension
– Arrhythmia
– 31 complications per 1000 procedures
Cataracts
• Surgical Strategies
– Dilate eye and wash with povidone-iodine
solution
– Small self-sealing corneal or scleral incision is
made for phacoemulsification tip and IOL
– Injection of viscous material into anterior
chamber to maintain the stability of the eye
– Open the capsule with continuous tear
capsulotomy, inject saline, separate lens from
capsule with phacoemulsification
Cataracts
• Phacoemulsification introduced by Kelman
in 1967
– Ultrasound probe using piezoelectric crystals
to convert electrical energy into mechanical
energy
• Irrigation and aspiration of the cataract.
The posterior capsule is kept intact.
• Anesthesia is usually 1% lidocaine topical
Cataracts
• IOL
– First implanted by Ridley in 1949
– Currently it is a small, foldable silicone or
acrylic material injected into the capsule.
– Monofocal or multifocal lens are available
• Monofocal – distant vision only, near vision
requires glasses
• Multifocal – both – however, halos and loss of
clarity are down side
Cataracts
• Postoperative Care
– Topical eye drops
• Antibiotics – gatifloxacin or moxifloxacin
• Steroids for inflammation –prenisolone acetate 1%
• NSAI drops – ketorolac tromethamine0.5% to
prevent inflammation in the retinal
• Examined one day, one week, two weeks, 1
months and 3 months post op – glasses can be
prescribed in 2 weeks.
Cataracts
• Risk Benefits:
– Bleeding, infection, posterior dislocation of lens
material- intraoperative
– Post operative -High-level of pressure in the eye,
corneal swelling, retinal inflammation, dislocation of
the IOL, retinal detachment, infection
– Posterior capsule opacifications (PCO) – migration of
lens remnants to the visual axis of the capsule – less
common with improved technique – treat with laser
Cataracts
• Future –
– Laser, ultrasound – less heat generated,
– Pulse phacoemulsification – less heat – less
chance for wound burn
Cataracts
• Take home
– Most common cause of blindness worldwide, affecting
50% of the over 65 population
– Clouding of the lens which impairs light travel to the
retina.
– Age, female sex, smoking, white – nuclear
– Black, sun exposure – cortical
– Steroids – subcapsular
– MI 3 months prior is only risk factor- no preop
evaluation needed.
– Post op meds: gatifloxacin or moxifloxacin,
prenisolone acetate 1%, and ketorolac
tromethamine0.5%)
Glaucoma
• The triad of increased intraocular pressure,
degeneration of the optic nerve head, restricted
visual field – open angle glaucoma
• Visual impairment in 0.7% of those over 60, 4%
of those over 90
• IOP greater than 17.5 mmHg is associated with
a persistent loss of vision and underscores the
need to aggressively treat intraocular pressure
Glaucoma
• Diagnosed before loss of vision by
ophthalmoscopic examination of the optic nerve
to detect cupping.
–
–
–
–
Blacks
Advanced age
Family history
Elevated intraocular pressure- Goldman’s tonometer
is gold standard – but the Schiotz indentation
tonometer is cheap and easy to use – normal
pressure is 15 to 16 mmHg – those with pressures
over 21 are considered to have ocular hypertension
Glaucoma
• Dynamics of aqueous
humor:
– Produced by ciliary
body, circulates
around lens, through
pupil, and anterior
chamber
– Flows out through the
trabecular meshwork
into the venous
system –here-in lies
the problem
Glaucoma
• Treatment is started when there is optic
disc cupping or even when there is just
elevated pressure >21 (normal 15).
• The remainder of this discussion on
glaucoma will cover the drugs used to
treat this problem
Glaucoma
• Pharmacopoeia
– Topical inhibition of carbonic anhydrase
– Agonism of the alpha-adrenoceptor
– Safer beta-adrenoceptor antagonist
– Prostaglandin Analogues
– Enhancement of trabeuclar outflow and
uveoscleral outflow
Glaucoma
• Carbonic Anhydrase Inhibitors-sulfonamides- 1
drop tid
– Inhibition of carbonic anhydrase in the eye results in
decreased fluid transport across the ciliary body
resulting in decreased formation of aqueous humor
– Dorsolamide (Trusopt), brinzolamide (Azopt)- as
effective as timolol, additive to timolol, brinzolamide is
less irritant as its pH is 7.5 vs 5.6
– Burning, stinging, bitter taste, 15% - allergic
conjunctivitis
Glaucoma
• [beta]-Adrenoceptor Antagonist– Timolol – (Timoptic) – used since 1979lowers intraocular pressure – the method of
action is unknown, but may be related to
decrease in aqueous humor production
– Contraindicated in asthma, severe COPD,
bradycardia, third degree heart block, CHF
– Betaxolol – (Betoptic or Kerlone)- may have
decreased bronchoconstriction and causes
increased retinal blood flow.
Glaucoma
• Combination therapy
– Dorsolamide and timolol (Corsopt) – decreases
pressure by 50%
• [alpha]-Adrenoceptor Agonists
– Stimulate presynaptic feedback inhibition of
norepinephrine and reduce aqueous humor formation.
– .125% clonidine tid equal to pilocarpine, the standard
• Doses of .25% or .5% produced hypotension
– Brimonidine-(Alphagan)- reduces AH production, but
also increases uveoscleral outflow - .2% tid – as
effective as timolol
• Headache, dry mouth, fatigue, ocular discomfort
Glaucoma
• Prostaglandin Analogs;
– Latanoprost (Xalatan) –approved in 1996 –
more effective than timolol bid and is only
dosed qd. Causes increased pigmentation,
growth of eyelashes, conjuctival hyperemia
– Enhance uveoscleral outflow
– Other drugs in same class:
• Unoprotatone(Rescula), travoprost (Travatan),
bimatoprost (Lumigan)
Glaucoma
• Muscarinic agents – parasympathomimetic
drugs have been used since 1870’s.
– Contraction of the muscle of the ciliary body – pulls
scleral spur, opens trabecular meshwork, and
increases aqueous flow form the eye
– These agents are anticholinesterases
• Pilocarpine -.25% to 4% every 4 to 8 hours as needed
• Cause miosis and cataracts
• Ocusert- wafer placed under the lid once a week – less side
effects.
Glaucoma
• Cannabinoids
– 1971- smoking marijuana lowers intraocular
pressure by 45%
– No successful topical form and systemic
causes too many side effects
Glaucoma
• Take home points
–
–
–
–
–
–
–
DX and TX early – Schiotz tonometer, cupping of disc.
Risk: Age, black, family history
Drugs: CAI – decrease AH – Dorsolamide
Alpha agonist – decrease AH - Brimonidine
Beta blocker – unknown- Timolol
Prostaglandin analog- scleral-uveal –Lantaoprost
Muscarininc- opens the trabecula - Pilocarpine
Macular Degeneration
• Most common cause of blindness in the
Western World – 8 million people world
wide.
Macular Degeneration
• Macula is 5.5 mm in
diameter, fovea is at
its center – located
temporally from the
optic disc.
• Fovea is thinnest part
of the retina – no
blood vessels
• Preponderance of
cone cells – detailed
central vision
Macular Degeneration
• The retina is functionally 2 layers
– Rods and cones – connected to the optic
nerve
– Retinal pigment epithemlium and its basal
lamina called Bruch’s membrane – maintains
the integrity of the barrier between the choroid
and the retina
– The choroid is between the retinal and the
sclera
Macular Degeneration
• Causes:
– Risk factors : age, soft drusen, macular pigmentary
change, chorioidal neovascularisation in the other
eye, hypertension, smoking, family history
– The retinal pigment epithelium becomes less efficient
– results in accumulation of waste material called
drusen. The retinal pigment cells degenerate and
central vision is lost
– This is dry type age related MD – slowly progressive
– 5 to 10 years to blindness
Macular Degeneration
• Geographic pattern of
retinal pigment
epithelial atrophy
Macular Degeneration
• Disruption of Bruch’s
membrane– Choroidal
neovascularizationedema – disruption of
visual function – wet
type or exudative age
related MD
Macular Degeneration
• Clinical features
– Blurring of the central vision
– Reduced vision, metamorphopsia
• The lines on graph paper will appear wavy or
distorted
– Ophthalmoscopic examination – chorioretinal
atrophy on dry or macular edema on wet type,
associated with retinal hemorrhages and lipid
exudate
Macular Degeneration
• Retinal and choroidal
angiography
– Intraretinal
hemorrhage and
edema of macula
– Fluorescein angiogram
with leakage
– Indocyanine green
angiogram – choroidal
vasculature
Macular Degeneration
• Clinical Advances
– Laser treatments for choroidal neovascularization
– Radiation treatment may preserve near vision and
contrast sensitivity
– Prevention: High dose Zn and Vit A,C,E
– Lutein and zeaxanthin carotenoids – potent nativeantioxidants found in high concentration in the macula
– needs to be studied
– Suppression of vascular endothelial growth factor or
other antiangiogenic agents
Macular Degeneration
• Take Home Points
– Risk – age, soft drusen, htn, smoking, family
history
– Retina – retinal pigmented epithelium and
rods and cones
– Dry – failure of the RPE to remove waste
products – results in accumulation of stuffatrophy
– Wet- neovascularization of the Choroid –
breaks Burch’s membrane-edema
The Aging Eye
• References:
– “Age related macular degeneration”; BMJ Volume
326(7387); March 1 2003; pp 485-488
– “Recent Advances and Future Frontiers in Treating
Age-Related Cataracts”; JAMA volume 290(2); July 9,
2003; pp248-251
– “Drug Therapy-Medical Management of Glaucoma”;
volume 339(18); October 29 1998; pp1298-1307
– “New Glaucoma Medications in the Geriatric
Population: Efficacy and Safety”; JAGS volume 50(5)
May 2002; pp 956-962