When approached by his publisher (Elsevier) to do a third edition of Manual of Contact Lens Prescribing and Fitting with CD-ROM, optometrist Milton M. Hom, of Azusa, Calif., was reluctant. But, he changed his mind after he reviewed the 2000 edition and considered the innovations in contact lenses since then.

As he works on the third edition, Dr. Hom has come across an array of new contact lens designs and materials that will make fitting both the complicated and run-of-the-mill patient a lot easier.

Its prudent for us [optometrists] to play close attention to these new innovations, these new products that come out by the companies, because it determines how we practice, and it improves the quality that we deliver to our patients, he says.
We checked with manufacturers and learned about the innovations that were introduced within the last year.

Gas Permeable Lenses
ContinuVu (Essilor)

Type: Progressive-add multifocal lens that eliminates the need for prism or truncation.
Why use this lens: Optometrist Clarence Chris Russell, of Valrico, Fla., recently fit ContinuVu on patients who were dissatisfied with the optics of other soft bifocal contact lenses. They not only had no problems adapting to the progressive lens, but they were also able to adapt to the material of the lens, he says. Dr. Russell says this lens simulates the natural progressive design found in glasses.
Prescriptions range: Custom made; add power to up to +3.00D.
Base curves: All.
Diameter: 9.3 to 10.3mm.
Wear schedule: Daily wear.
Replacement schedule: According to the O.D.s recommendations.

Dyna Z Intra-Limbal (Lens
Dynamics Precision Lenses)

Type: For patients who have pellucid marginal degeneration, globus cones, low cones post-graft or reverse curves post-refractive surgery. Made with Menicon Z material (Dk 189Fatt Method).
Why use this lens: Michael Brian, O.D., of Henryetta, Okla., likes how the lens can be modified. He recalls one patient who underwent penetrating keratoplasty in one eye, had keratoglobus in the other, and had 9.00D of astigmatism. Glasses provided limited visual improvement. Dr. Brian decided contacts would be needed and chose the Dyna Intra-Limbal large diameter standard series. Still, he says fitting this patient was challenging, particularly on the post-PK eye.
Because of the large amount of astigmatism, the lens initially didnt fit right, he explains. It would rock along the axis of the astigmatism. So, Dr. Brian asked the company to steepen the lens in specific portions. The patient achieved 20/20 acuity in the post-PK eye.
Prescription range: +25 to -25D
Base curves: 9.20mm to 6.60 mm. in 0.05 steps.
Diameter: 11.2mm to achieve 0.5 to 1mm movement. The diameter may need to be smaller or larger so the overall diameter is at least 0.2mm smaller than the cornea.
Edge profile: Desired edge lift will show 0.2mm of clearance. Flatter and steeper edge lifts are available.
Wear schedule: Waking hours.
Replacement schedule: One to two years.

ESSential Concentric S-Form ADD
(CSA, Blanchard Contact Lens Inc.)

Type: A segmented translating aspheric multifocal with a combination of posterior and anterior S-Form ADD designs; available for the ESSential GP or ESSential Xtra GP lenses in series 1, 2 and 3. The combination S-Form ADD creates a segmented translating aspheric multifocal.
Why use this lens: Douglas Benoit, O.D., of Concord, N.H., recommends this lens because it offers patients intermediate and near vision. And, It does not create problems as far as compressing or molding the cornea, he says.
Dr. Benoits advice: Assess how the lens is positioning as well as pupil size because the CSA enhancement adds extra power to the front part of the lens in an annular design. Thus, the lens needs to translate up on downgaze to get the full visual effect at near.
Prescription range: +0.50D to +2.00D (anterior S-Form Add). You can enhance the posterior add available with each series, for a combined add of up to +4.00D.
Base curves: Custom made.
Diameter: Not less than 8.8mm.
Wear schedule: Waking hours.
Replacement schedule: One to two years.

(ABBA Optical, Inc.)

Type: Hybrid multifocal that includes a progressive aspheric posterior surface combined with a segmented anterior surface. The lens also has an aspheric transition zone for added visual and wearing comfort.
Why use this lens: Joseph M. Dzik, O.D., of Chattanooga, Tenn., says he likes this hybrid progressive because it prevents those patients who require more than a +1.75D add from having to use reading glasses with their contacts.
He recalls one patient he fit with a variable focus bifocal contact lens several years ago. When he hit his 50s, the lenses were no longer giving him enough power for reading contracts and things like that, and he asked if there was anything new, so I fit him in the EZEyes, Dr. Dzik says. Now, he can see any size print he wants to see. Hes seeing 20/20 at far and 20/20 at near.
Prescription range: Up to +4.00D add in 0.25D steps.
Base curves: Made to order depending on the K values and Rx.
Diameter: Normally about 9.6mm. The lenses can be customized.
Wear schedule: Waking hours.
Replacement schedule: 12 to 24 months, or as prescribed.

Marquis GP Multifocal
(Curve Differential Optics)

Type: A multifocal that combines a spherical front surface with a multi-aspheric posterior surface and precisely adjusts the reading zones for each of the available 17 Equivalent Curves (EQ).
Why use this lens: Robert Deck, O.D., of Lake Orion, Mich., says the lens reduces chair time. There is only one diameter, and the optical zones are controlled by the EQ, he says. There are only two adds: low and high. Therefore, you know quickly whether the patient is going to be successful with the Marquis GP Multifocal.
Prescription range: Low add (+1.75D or less) and high add (+2.00D or greater).
Equivalent curve: 6.7 to 8.3mm (0.1mm steps), customized.
Base curve: N/A.
Diameter: 9.5 mm.
Wear schedule: Waking hours.
Replacement schedule: Up to O.D.

Soft Lenses
ACUVUE ADVANCE with hydraclear
(Vistakon, a Division of Johnson & Johnson Vision Care Inc.)

Type: A silicone hydrogel with a Dk/t value of 85.7. The lens blocks more than 90% of UVA and 99% of UVB rays.
Why use this lens: John McClane, O.D., of Amelia Island, Fla., likes this lens because it eliminates dryness. For example, he says, one female patient who wore the ACUVUE 2 lens experienced so much dryness and discomfort by each afternoon that she needed to remove her lenses, and use a lot of rewetting drops. The womans work environment wasnt much help, as ceiling fans and the air-conditioning system surrounded her.
We switched her into the ACUVUE ADVANCE, and all of those problems just seemed to go away, he says. She is now able to wear the lenses all day long at work.
Dr. McClane says he now offers ACUVUE ADVANCE to all his daily wear patients.
Prescription range: 6.00D to +4.00D (0.25D steps).
Base curves: 8.3mm and 8.7mm.
Diameter: 14mm.
Wear schedule: More than 9 hours.
Replacement schedule: Recommended for two-week daily wear.

Extreme H2O G60 S-Xtra
(Hydrogel Vision Corp.)

Type: A hydrogel lens available in steeper base curves and in plus powers. Designed to fit patients with a wider range of steeper corneas.
Why use this lens: Optometrist Ken Daniels, of Hopewell, N.J., likes this lens because, The lens parameters are consistent and stable from the beginning to the end of the day due to the water balance of the lens. He adds that because the Extreme H2O is a Group II lens, it has a low frictional component to the ocular surface that prevents binding and enhances comfort.
Prescription range: 0.25D to 8.00D (8.3 base curve); +6.00D to 8.00D (8.6 base curve) in .50D steps -6.00 for both.
Base curves: 8.3mm or 8.6mm.
Diameter: 14.2mm.
Wear schedule: Two week daily wear recommended.
Replacement schedule: Two-week disposable.

(CIBA Vision)

Type: Silicone hydrogel with 138 Dk/t; scheduled for launch in September, 2004.
Why use this lens: Steven I. Bennett, O.D., whose Ann Arbor, Mich., practice participated in clinical trials, has fit 02 OPTIX on about 25 patients who had problems wearing low-Dk lenses. These patients, he says, increased wearing time, and the lenses did not get as coated.
Although the lenses are not approved for extended wear (CIBA is currently working on this), he feels there is a better safety margin for noncompliant patients than with other low-Dk materials.
Prescription range: 1.00D to 6.00D.
Base curves: 6mm.
Diameter: 14.2mm.
Wear schedule: Daily wear.
Replacement schedule: Two-week disposable.

Biomedics 55 Premier
(CooperVision/Ocular Sciences Inc.)

Type: A soft disposable, aspheric lens that corrects for spherical aberration in both the lens and the eye, allowing for clearer vision. Unlike its predecessor, the Biomedics 55 spherical lens, the edges of the Biomedics 55 Premier are rounded. Why use this lens: Gregory Forsyth, O.D., of Raleigh, N.C., helped conduct some preclinical trials. He says the lens offers better acuity than the previous Biomedics 55 to patients with low amounts of against-the-rule astigmatism. Although patients did not complain of discomfort with the prior lens, they reported im-proved comfort with the Premier version, Dr. Forsyth says.
During the redesign of the Biomedics 55 lens, the manufacturer added the asphericity only on the front surface but left the base curve the same. Therefore, Biomedics Premiere fits the same as Biomedics 55, Dr. Forsyth says.
Prescription range: -10.00D to +6.00D in (0.50 steps).
Base curves: 8.6mm, 8.9mm
Diameter: 14.2mm.
Wear schedule: Approved for daily and extended wear.
Replacement schedule: Two weeks.

Emerald Orthokeratology Lens
(Euclid Systems Corp.)

Type: Overnight vision correction for low myopes. Features the Bos-ton Equalens II high-Dk material.
Why use this lens: Gary Gerber, O.D., of Westwood, N.J., has found the lens to be successful for his patients who were on the fence for LASIK surgery. For example, one patient who skis a lot planned to have LASIK but agreed to try over- night ortho-K with the Emerald lens first. Five years later, the patient still wears the lenses nightly and has even referred patients to his practice, Dr. Gerber says.
Prescription range: Recommended for 1.00D to 5.00D of myopia.
Base curves: N/A
Wear schedule: 8 to 12 hours of overnight wear.
Replacement schedule: Annual.

Vol. No: 141:08Issue: 8/15/04