Intraocular Lens Update
lens implantation for patients who have cataracts is common and usually successful.
Improved aphakic IOLs have led to a revitalization of IOLs for non-cataractous patients
because many aphakic IOL designs and surgical procedures are also applicable
for phakic IOLs. Refractive surgery now encompasses corneal refractive surgery,
aphakic IOLs and phakic IOLs. This article will discuss the various designs, procedures
and applications of aphakic and phakic IOLs as well as complications, clear lens
extraction and intracorneal implants.
events have occurred in the evolution of aphakic IOLs. In 1949 the first IOL implant
on a human was performed using a lens made from polymethylmethacrylate (PMMA). The
surgeon placed the IOL in the posterior chamber after extracapsular cataract extraction
(ECCE). Many problems from both the lens design and placement location ensued. For
the next two decades, attempts to find a better fixation location included anterior
chamber (AC), iris and iridocapsular placement. All of these were more problematic
than the posterior chamber (PC) fixation, so this became the preferred position
and many subsequent refinements have brought it to its present status.
An important development
in 1967 was the phacoemulsification and aspiration procedure, which allowed a small
incision and control for cataract removal. Unfortunately, because of the existing
IOL design and PMMA material, the incision had to be enlarged for IOL insertion.
There have been many improvements of phaco over the years.
1977 an IOL with flexible posterior haptics became available. Subsequent developments
allowed for placement in the capsular bag. Combining the concepts of intracapsular
phaco and IOL capsular bag fixation eventually led to today's minimally compression-resistant
posterior chamber IOL (PCIOL) with short haptic configuration.
brought the introduction of viscoelastic 1% sodium hyaluro-nate (Healon), which
protected the corneal endothelium during IOL implantation and also made it
easier to perform anterior capsulotomy. This was followed in 1984 by the first foldable
silicone IOL. Manufacturers improved both the design and material, and in 1992 came
the introduction of a procedure involving only a 3mm-wide, self-sealing, clear corneal
incision that could accommodate phaco and IOL insertion. Now surgeons could implant
silicone foldable IOLs without the need for cautery, scissors or sutures, although
one suture is sometimes used.
1992 cataract surgery with only topical anesthetic was introduced and then improved
with the addition of intracameral anesthesia. In 1995 the soft, foldable acrylic
IOL received Food and Drug Administration (FDA) approval for use in the United
are several dozen IOL manufacturers and almost a thousand variations of IOLs,
but a majority of surgeons use silicone or acrylate foldable IOLs, temporal clear
corneal incisions of about 3mm, topical-intracameral anesthesia and adjunctive viscoelastic
basic categories of IOL materials are PMMA, acrylic, acrylic hydrogel and silicone.
PMMA is a good
IOL material, but it can cause mechanical irritation and inflammation and it requires
a larger incision for implantation, which can cause intraoperative complications
and delay postoperative healing. Because small-incision surgery and phacoemulsification
are desirable, rigid IOL materials are less preferable.
acrylics are soft, hydrophobic and mechanically weak. Copolymerization with methacrylates
can maintain the flexibility of the acrylate and increase mechanical strength. Acrylates
have a hydrogen group that, when replaced by a methyl group, creates a methylacryate,
which can be copolymerized with other mono-mers such as PMMA and Poly-HEMA. A wide
range of properties can be produced with various tensile strength, elongation and
are hydrophilic and can be copolymerized with a variety of monomers to produce desired
properties. For IOL materials, acrylate and methacrylate-based materials are
most commonly used with hydrogels.
grade silicone polymers have been used for drains in glaucoma surgery, scleral buckles
and oculoplastic surgery as well as in IOLs.
IOL materials are under investigation.
25 percent of U.S. ophthalmic surgeons prefer silicone foldable IOLs, but about
twice this number prefer acrylic foldable IOLs. Examples of silicone foldable IOLs
are RMX3 (Staar Surgical) and SLM2 (Allergan), and of acrylic foldables are Acrysof
(Alcon) and Sensar (Advanced Medical Optics [AMO], Figure 1).
Special Design Aphakic IOLs
aphakic IOLs have been spherical, single-vision and with some ultraviolet absorption.
Many of the newer IOLs are designed to correct presbyopia, astigmatism, aberrations
or to block specific wavelengths of light.
There are optical parallels between presbyopes who wear contact lenses and those
who have IOLs. One obvious parallel is that both groups need one power correction
for distance and a different one for near. Either group can attain this by correcting
both eyes for distance or for near and wearing spectacles (for the opposite vision
need) over the contact lenses or IOLs. Alternatively, patients can wear single-vision
lenses in a monovision modality.
parallel between presbyopic users of contact lenses or IOLs is that some of them
would prefer to not need auxiliary spectacles. Although the majority of presbyopic
lens wearers do use single-vision lenses (with both eyes corrected for the same
distance) with auxiliary spectacles or monovision, an increasing number are using
some type of bifocal or multifocal contact lenses because of their improved optical
additional parallel is that the general optical concepts used for bifocal or multifocal
contact lenses (diffraction or refraction) are also used for bifocal or multifocal
IOLs. The overall designs of the contact lenses or IOLs both include concentric
rings of two or more zones of various optical powers and aspheric progressive (on
anterior surface of IOLs) or diffractive (on posterior surface of IOLs) optics.
manufacturers have developed or are developing many bifocal or multifocal IOLs,
the three that have FDA approval for use in the United States are ReZoom (AMO),
ReStor (Alcon) and Crystalens (Eyeonics, Figure 2).
predecessor to ReZoom was Array, which produced glare for many patients. ReZoom's
improved refractive optics have decreased this using a five-optical-zone design
of concentric rings in which the central zone is for distance and subsequent zones
alternate near and distance correction. It also features aspheric transitions between
adjacent zones designed for intermediate distance correction. The add power at the
corneal plane is about +2.25D.
ReStor IOL uses special diffractive optics. It has 12 diffractive steps that
start with a 1.3μ height and taper to a 0.2μ height for the 12th step.
The effective add is about +3.00D.
Crystalens' optics are monofocal, contrasted to the multifocal optics of ReZoom
or ReStor. Crystalens has a hinged-plate haptic that allows the IOL to move forward.
When a patient attempts to accommodate, the ciliary body contracts, the tension
on the capsular bag decreases and the pressure within the vitreous body produces
the IOL's forward motion and near focus with an average add effect of +1.00D to
final parallel between bifocal or multifocal contact lenses and IOLs is optical
disturbances. Practitioners don't have the same variety of adds to prescribe with
contact lenses or IOLs as they would have with spectacles. Also, the multi-zoned
ReZoom and ReStor cause some light scatter, glare and halos, especially under reduced
illumination. Some patients adjust to this better than others. In addition, distance
and/or near contrast sensitivity may decrease. Because the Crystalens is monofocal,
it's less likely to produce glare, halos or decreased contrast sensitivity.
Small-incision procedures have minimized surgically induced corneal astigmatism.
Surgeons can correct some pre-existing corneal astigmatism using limbal relaxing
incisions, using peripheral intralimbal arcuate relaxing incisions, by rotating
the basic cataract incision to the steep axis or a combination of these. But the
efficacy varies, and the development of toric IOLs is geared toward a more consistent
efficacy without surgically weakening the cornea and increasing higher-order aberrations
accurately correct pre-existing corneal astigmatism with a toric IOL, the IOL must
be positionally stable in the capsular bag, the surgeon must place the IOL at the
correct axis during surgery and there should be no surgically induced corneal astigmatism.
front-surface toric Staar Surgical Toric IOL is a single-piece silicone IOL whose
plate haptics have large holes to lock and stabilize the IOL in the capsular bag
by migrating epithelial cells. It has linear axis marks on the front surface's periphery
for axis alignment. A range of spherical powers are available as well as labeled
cylinder powers of 2.00D and 3.50D, which after implantation respectively have an
effect of about 1.40D and 2.30D.
method to correct higher amounts of post-operative corneal astigmatism is LASIK.
Of course, spectacles with the appropriate cylindrical correction is an easy option.
IOLs Even in healthy eyes, contrast sensitivity decreases with age, which
decreases functional vision probably due to changes of the crystalline lens' spherical
aberration. That is, the young crystalline lens' negative spherical aberration changes
so that it reduces the older crystalline lens' compensation for the positive spherical
aberration of the cornea. Consequently, retinal image quality decreases. Conventional
spherical IOLs have positive spherical aberration. This adds to the cornea's positive
spherical aberration, which increases spherical aberration.
goal of aspheric IOLs is to improve functional vision and contrast sensitivity by
a lens design that induces negative spherical aberration to help offset the cor-nea's
positive spherical aberration. Three aspheric IOLs have FDA approval: AcrySof IQ
(Alcon), SofPort LI61AO (Bausch & Lomb) and Tecnis Z 9000 (AMO).
pre-surgical average corneal spherical aberration is +0.25μ; the AcrySof and
SofPort add –0.15μ spherical aberration and the Tecnis –0.27μ.
Ophthalmic surgeons can measure a patient's pre-operative corneal spherical aberration
and choose the aspheric IOL that will best help offset it. The goal is to leave
the patient with about +0.10μ, which seems to produce the best contrast sensitivity
and functional vision including for night driving.
the pre-operative cornea doesn't always have the same amount of spherical aberration
as the post-operative cornea. Surgery and incisions can induce HOAs such as coma.
In the future more options may be available in the IOLs' negative spherical aberration
range, which would allow greater customization.
technology is Calhoun Vision's light adjustable lens. This silicone IOL with photosensitive
material uses wavefront sensing and can be adjusted after implantation to correct
refractive errors and perhaps coma and spherical aberration. This lens is a foldable
three-piece IOL with a cross-linked photosensitive silicone polymer matrix, a homogeneously
embedded photosensitive macro-mer and a photo initiator. Irradiation of various
areas of the lens can change spherical and toric power and perhaps reduce or eliminate
Blockage All IOLs block some UV light, but blue-light absorbing IOLs are
also available. Studies are ongoing to determine which type of absorption provides
the best retinal protection as well as the best visual performance under photopic
and mesopic lighting conditions. AcrySof Natural (Alcon, Figure 3) blocks both UV
and blue lights.
IOL Surgery Complications
IOL surgery is a very common procedure that usually produces good results.
However, complications can occur ranging from optical deficiencies to anterior or
posterior segment problems. Many of these have a low incidence and/or can be managed.
The most common
cause of IOL decentration occurs when a surgeon inserts the inferior haptic into
the capsular bag and the superior haptic into the ciliary sulcus, which causes upward
movement of the IOL optic. Superior migration of PCIOLs produces the "sunrise syndrome"
while inferior migration produces the "sunset syndrome."
capture occurs when some or all of the optic is within the pupil and the rest of
the lens is behind the iris. It usually occurs one to two months postoperatively,
and the incidence with silicone or acrylic foldable lenses is very low.
chamber inflammation and persistent iritis in patients after ECCE and PCIOL implantation
probably averages about 2 percent. It results from the breakdown of the blood-aqueous
(UGH) more commonly occurs with anterior chamber IOLs (ACIOLs), but it occasionally
occurs with PCIOLs. It's a rare complication and results from mechanical trauma
on the angle or iris. Pupillary block glaucoma results when the IOL blocks aqueous
flow through the pupil. Malignant glaucoma occurs when anterior aqueous flow is
bullous keratopathy relates to progressive endothelial loss. It has a greater incidence
with ACIOLs and iris-fixated IOLs, but less than 1 percent with ECCE and PCIOLs.
crystalline lens' epithelium exists on the surface of the anterior lens capsule
(where A-cells are located) and on the surface of the capsule at the equator (where
E-cells are located). Anterior subcapsular opacities with some aphakic PCIOLs result
from A-cell proliferation. E-cells are primarily responsible for "secondary cataract"
(posterior capsular opacification, or PCO) after ECCE and IOL placement "in
the bag." Cells proliferate and migrate onto the central region of the posterior
capsule opacification (ACO) usually occurs within a month or so after cataract surgery.
It occurs along the anterior rim of the capsular bag, and its peripheral location
away from the major portion of the anterior surface of the PCIOL has little effect
clinically manifests as fibrous membrane and Elsching pearls. Typically the fibrous
opacity develops two to six months postoperatively and is more common with silicone
IOLs, while the Elsching pearls can develop several months to years after surgery
and are more common with PMMA IOLs. Although various studies show different results,
it seems that about 50 percent of patients who have ECCE/IOL will need neodymiumiyttrium-aluminum
garnet (Nd:YAG) laser capsulotomy within four years postoperatively. The rates are
believed to be lower with acrylic IOLs.
capsulotomy has a four times higher risk of developing retinal detachment (RD),
probably because of loss of hyaluronic acid from the vitreous, its destabilization
and disruptions in the vitreoretinal interface. Surgeons may reduce the incidence
of PCO by intraoperative polishing of the posterior capsule and/or present day acrylic
or silicone IOLs.
macular edema (CME) is another common complication. Although estimates vary, with
ECCE incidence of angiographic evidence is about 15 percent but clinically symptomatic
CME is only about 2 percent. CME typically appears one to three months after surgery,
but infrequently can occur months or years later. Usually it resolves spontaneously,
but about 1 percent of cases are chronic and last more than six months. Use of ketotolac
tromethamine both pre- and post operatively significantly decreases both angiographic
and symptomatic vision problems of CME.
can cause dislocated crystalline lens fragments into the vitreous cavity. Surgeons
can reduce the chance of this happening by using the lowest possible vacuum and
power settings and infusion pressures. Dislocation of the IOL itself into the
vitreous is quite rare.
after ECCE has a less than 1 percent incidence, much less than after ICCE. RDs usually
occur within six months postoperatively, but pseudoaphakia increases the risk of
RD even six years later. Major risk factors for postoperative RD are pre-operative
conditions such as high myopia (eight times higher risk), retinal lattice degeneration
(10 times higher risk), family history of RD and hereditary vitreoretinal degeneration.
Intraoperative factors that predispose to RD include crystalline lens fragments,
disruption of the posterior capsule (13 times higher risk) and Nd:YAG laser capsulotomy
(four times higher risk). Postoperative ocular trauma also produces a four times
relative risk increase. Retinal breaks in pseudoaphakic RD are often anterior near
the vitreous base and therefore more difficult to detect.
IOLs Some patients are aphakic because of ICCE. Options for correction
include spectacles or contact lenses, but there are patients who can't or won't
use them and for whom secondary IOLs are a consideration. Placement of secondary
IOLs may be in the anterior chamber on the iris, or in the posterior chamber with
bag and sulcus fixation or sulcus suture fixation. Modern IOL designs and surgical
procedures have somewhat reduced complications.
IOLs aren't new. In 1983 there was a report of a phakic IOL implanted in the
anterior chamber (AC) using the irido-corneal angle for support. Over the next
decade, a number of phakic lens designs were developed and implanted, with little
success because of designs that used solid materials with thick peripheries and
because of challenging surgical technique. This produced a negative reaction among
the ophthalmic professions and regulatory agencies that resulted in little phakic
IOL use and development. In the mid-1980s, manufacturers developed newer and
better-designed phakic IOLs. Combined with advances in aphakic IOL surgery
that could be applied to phakic IOL implantation, a rebirth of interest resulted
because of significantly improved results. Phakic IOLs are categorized by their
location in the eye: AC angle-fixated, iris-supported and PC. Worldwide there are
a fairly large number of various phakic IOLs in use, but fewer in the United States
have received FDA approval. Most of the knowledge about phakic IOLs has been
gathered by use and studies outside of the United States and from FDA-related clinical
studies in the United States. Predominant phakic IOLs used worldwide include the
Verisyse/Artisan (AMO) and the Implantable Collamer Lens (ICL, Staar Surgical) (Table
and Corneal Refractive Surgery Improved phakic IOLs offer another option
for refractive surgery. Corneal refractive surgery is probably preferable for low
and moderate myopia because LASIK and its variants of laser subepithelial keratectomy
(LASEK or Epi-LASEK) generally produce good comfort, quick recovery and stable results.
However, efficacy and predictability decrease with high myopia. Similarly, LASIK and
conductive keratoplasty (CK) are more effective in treating low hyperopia than high
myopia. Thus, phakic IOLs may be preferable for myopia greater than about 10.00D
and hyperopia greater than about 3.00D. Also note that phakic IOL implantation is
In this context, bioptic simply means the use of more than one type of refractive
surgery in two different planes for the same eye. One example is a phakic IOL to
correct a spherical error and subsequent LASIK to correct corneal astigmatism. Or
for very high myopes or hyperopes, correcting some of the spherical refractive error
with a phakic IOL and the rest with LASIK (in cases in which the refractive error
is too great for safe and effective correction by LASIK alone).
Chamber Considerations In addition to the degree of refractive error, other
considerations for phakic IOLs could include stable refraction coupled with a patient's
inability or disinterest in wearing contact lenses. Phakic ACIOLs (PACIOLs) occupy
space, so the anterior chamber depth needs to be great enough (at least 3.4mm) to
have the phakic IOL and maintain sufficient separation from the corneal endothelium
(which should have a cell count of at least 2,250 cells/mm2). This ensures
that the PACIOL causes no mechanical trauma to the corneal endothelium.
accurate measurement of the anterior chamber is essential with PACIOLs. Ultrasound
scans, the IOL Master (Carl Zeiss Meditec) and the Orbscan II (B&L) are
traditionally used. Three newer instruments for measuring AC depth are the Pentacam
(Oculus), Vosante OCT (Carl Zeiss Meditec) and Artemis #2 (Ultralink).
PCIOLs were originally developed because of concerns about PACIOLs contacting the
cornea and also creating an ovalization of some pupils. Because the phakic PCIOL
is positioned between the back of the iris and the front of the crystalline lens,
there is some concern about mechanically induced cataracts.
IOLs and Trends The Verisyse Phakic IOL (AMO) is an FDA-approved iris-fixated
PACIOL. It's a one-piece compression-molded PMMA lens with a length of 8.5mm and
an optic diameter of 5mm or 6mm. Available powers are –3.00D to –23.50D.
Visian Toric ICL (Staar Surgical) is a phakic PCIOL made of a proprietary UV-blocking
porcine collagen/poly-HEMA copolymer. Powers are –6.00D to –16.50D.
AcrySof is an angle-supported, foldable PACIOL. Powers are –6.00D to –16.50D.
three phakic IOLs are comparable in some ways with aphakic IOL development.
For example, for implantation the Verisyse PMMA lens needs a large incision and
three to six sutures. Large incisions delay visual rehabilitation and have more
potential for wound leaks and infection than small incisions, just as for similar
aphakic IOL configurations. The foldability of the AcrySof phakic IOL is in line
with the need for and development of foldable aphakic IOLs, and the Visian Toric
ICL follows the same path as the development of toric aphakic IOLs. Not only are
there aphakic and phakic IOLs to correct astigmatism, but also to correct presbyopia
and spherical aberration and to filter blue light. In essence, many of the advancements
in lens materials, lens design, optics and surgical procedure developed over the
years for aphakic IOLs have been applied to phakic IOLs.
present risk-to-benefit ratio makes phakic IOLs a viable alternative to other types
of refractive surgery for high ametropia. As the risk-to-benefit ratio improves
with better phakic IOLs and surgical procedures, the use of phakic IOLs may encompass
more than the higher ametropias. But as with aphakic IOLs, potential complications
of their more recent and limited usage, there are fewer studies in general and particularly
fewer long-term studies for phakic compared to aphakic IOLs. Also, as with aphakic
IOLs the continuing development and evolution of phakic IOLs and related surgical
procedures try to address complications and to minimize or eliminate them. Phakic
IOL complications include endothelial cell loss or damage, elevated IOP, pupillary
changes, iris alterations, uveitis, RD and cataract formation. The first is more
common with ACIOLs and the last with PCIOLs.
IOLs and Clear Lens Extraction
crystalline lens provides high plus power to the eye, and a high myope's eye has
excess plus power. Therefore, for over 100 years practitioners have thought about
and at times removed a clear, healthy crystalline lens to better balance the axial
length and overall power of an eye. Of course, ophthalmic surgeons have to compare
the risk-to-benefit ratio of clear lens extraction (CLE) with other procedures for
highly myopic patients. The major risk is RD.
As with cataract
surgery, CLE has become somewhat more viable because of the use of small self-sealing
incisions, phacoemulsification, viscoelastic agents and foldable IOLs. But the risk-to-benefit
ratio is better for patients who have cataracts than for patients who have a clear
have also performed CLE for high hyperopes.
intracorneal implants have been tried over the years, but the only inlays now used
to a large degree are Intacs (Addition Technology) intrastromal corneal ring segments.
Surgeons place these at about two-thirds depth in the peripheral stroma outside
the cor-nea's central optic zone. They reshape the anterior corneal surface to reduce
or eliminate 1.00D to 3.00D of myopia.
The current design
of intracorneal ring segments is two segments each with an arc length of 150 degrees.
At the superior end of each segment is a small positioning hole to help the ophthalmic
surgeon manipulate the segments after insertion.
occupy space within the cornea, which forces an anterior corneal curvature flattening.
Thicker Intacs occupy more space and create greater anterior corneal flattening
and myopia reduction; an increase of about 0.70D of flattening occurs for every
0.05mm increase of device thickness. The available thicknesses in the United States
are 0.25mm (predicted correction of –1.03D), 0.30mm (predicted correction
of –2.00D) and 0.35mm (predicted correction of –2.75D), with 0.40mm
and 0.45mm available elsewhere to correct up to –4.50D.
Technology also received a Humanitarian Device Exemption from the FDA in 2004 to
market Intacs for reduction or elimination of myopia and astigmatism in patients
who have keratoconus and where functional vision is no longer achievable with contact
lenses or eyeglasses.
about two decades, vast improvements have occurred in the safety and efficacy of
aphakic IOLs and corneal refractive surgery. Many millions of patients receive these
procedures each year. Phakic IOLs probably won't experience as dramatic an increase
as aphakic IOLs, but phakic IOL usage may increase significantly. CLS
Dr. White is
a professor at New England College of Optometry and Continuing Education Editor
of Contact Lens Spectrum.
obtain references for this article, please visit http://www.clspec-trum.com/references.asp
and click on document #135.
1. The first aphakic IOL implanted
was made from:
and aspiration was first developed in:
3. U.S. ophthalmic surgeons
most use IOLs made of which material?
4. Which is a silicone
foldable aphakic IOL?
5. Which aphakic IOL uses
6. The effective add of
the Crystalens is about:
a. 2.50D to 3.00D
b. 1.75D to 2.25D
c. 1.00D to 1.50D
d. 0.25D to 0.75D
7. Which of these would
probably produce the least glare and halos?
d. All the same
8. The Staar Surgical Toric
ICL's labeled cylinder power of 3.50D has an effective implanted cylinder power
9. The average corneal
spherical aberration before cataract surgery is about:
10. Which IOL has
a photosensitive material and can be adjusted after implantation?
a. AcrySof IQ
b. SofPort LI 61AO
d. Tecnis Z 9000
11. Which IOL blocks
a. AcrySof Natural
c. Tecnis Z
12. Anterior chamber inflammation
and iritis after ECCE and PCIOL probably averages about:
a. 2 percent
b. 4 percent
c. 6 percent
d. 8 percent
13. PCO or "secondary cataract"
is due to which type of cells?
14. About what percent
of cataractous patients who undergo ECCE and implantation with need Nd:YAG laser
capsulotomy within four years postoperatively?
15. The fluorescein angiographic
incidence of cystoid macular edema with ECCE and aphakic IOLs is about:
a. 35 percent
b. 25 percent
c. 15 percent
d. 5 percent
16. Phakic IOLs may be
preferable to corneal refractive surgery for myopes of over:
17. Anterior chamber depth
for phakic anterior chamber fixated IOLs should be at least:
18. The Verisyse phakic
IOL is made of:
19. The main risk in clear
crystalline lens extraction is:
a. retinal detachment
c. cystoid macular edema
d. posterior capsular opacification
20. With Intacs a thickness
increase of 0.05mm of the inlay creates about what amount of corneal flattening
The following article is offered in conjunction
To obtain credit for
this course, you must: 1. Be a licensed optometrist; 2. Read and study the course
presented in Spectrum; 3. Complete the test within nine months of the publication
date of this issue; 4. Obtain a grade of 70 percent or higher on the exam.
test by blackening the square that corresponds with your response on the pull-out
reply card. Stamp and mail the self-addressed card. Tests must be postmarked
by November 30, 2007.
There is no tuition
or processing fee to you. The CE section is subsidized by Vistakon to support your
professional enhancement. The New England College of Optometry will correct only
the optometry tests, notify optometrists of their scores, and issue certificates
of credit to those who have passed the test. For information regarding your CE credits
and/or certificates, optometrists only can call NEWENCO's Center for Continuing
Education at (617) 236-6283. Please allow 12 weeks for processing, which will be
done in the order that they are received. You are encouraged to respond early.
state board has specific regulations about recognizing
for continuing education certification (see below). If you have questions about
your particular state, please confirm with your state board. This course has also
been submitted for approval by the Council on Optometric Practitioner Education
This course is supported
by an educational grant from VISTAKON®, Division of Johnson &
Johnson Vision Care, Inc.
ARTICLE IS APPROVED FOR UP TO 2 CREDITS FOR OPTOMETRY.
3 hours per year
Alaska Allows 6 hours correspondence
credit in 2 years renewal
Arizona Limit 6 hours of
correspondence credit per 2 years
Arkansas Allows 4 hours
California Allows 20 hours
every 2 years
Colorado Allows 8 hours
every 2 years
Connecticut Does not recognize
Delaware Allows 2 hours
every 2 years
Dist. of Columbia Allows
6 hours every 2 years
Florida Does not recognize
Georgia Allows 5 hours
every 2 years
Hawaii Allows 6 hours every
Idaho Allows 6 hours per
Illinois Allows 2 hours
every 2 years
Indiana Allows 2 hours
of credit per article
Iowa Limit 10 hours of
correspondence credit per 2 years
Kansas 1/2 credit per article:
total 3 credit hours per year
Kentucky Does not recognize
Louisiana Does not recognize
Maine State association
only accepts correspondence
Maryland Allows 6 hours
every 2 years
Massachusetts 1/2 credit
per article: total 2 hours per year
Michigan Allows 2 hours
of credit per article
15 hours during each two-year cycle
Mississippi Allows 4 hours
Missouri Allows 2 hours
of credit per article
Montana Limit 6 hours of
correspondence credit per year
Nebraska Allows 2 hours
every 2 years
Nevada Allows 12 hours
in renewal period
New Hampshire Allows 2
hours per article
New Jersey Allows 12 hours
every 2 years
New Mexico Does not recognize
New York Allows 12 hours
per 3 years (ocular therapy and/or pharmacology only)
North Carolina Limit 4
hours of correspondence credit per year
North Dakota Allows 8 hours
every 3 years
Ohio Allows 10 hours per
Oklahoma Allows 10 hours
Oregon Accepts up to 10
hours maximum per biennium
Pennsylvania Allows 6 hours
every 2 years
Rhode Island Allows 2 hours
South Carolina Does not
recognize correspondence courses
South Dakota Allows 6 hours
every 3 years
Tennessee Does not recognize
Texas Limit 4 hours of
correspondence credit per year
Utah Does not recognize
Vermont Allows 1 hour per
Virginia Allows 2 hours
of credit per article
Washington Allows 10 hours
every 2 years
West Virginia Does not
recognize correspondence courses
Wisconsin Does not allow
correspondence course credit
Wyoming Does not recognize
Contact Lens Spectrum, Issue: February 2007