Case 1: Spherical Aberration Corrected
By Dr. Steve Byrnes
|Distance Power||+20.00D to -20.00D in 0.25D steps|
|Add Power||+1.00D to +3.50D in 0.25D steps|
|Base Curve||6.9mm to 8.5mm in 0.05mm steps|
|49.00D to 39.75D in 0.25D steps|
|Diameter||9.0mm to 10.00mm in 0.10mm steps|
|Material||Boston ES® recommended|
This is the Renovation Multifocal manufactured by Art Optical. The Front Surface Multifocal Add Power is available in 0.25 steps from +1.00 to +3.50 D. There is a wide range of parameters available to meet the needs of most of the presbyopic patients.
Multifocal Optics Options
3.95mm – standard pupils (7.9mm viewing area)
3.5mm – small pupils (7.0mm viewing area)
4.25mm – large pupils (8.5mm viewing area)
The benefit to this flexible distance/intermediate zone is it allows the eye care practitioner to customize the lens for the patient. For patients with small pupils, the 7.0mm viewing area will enhance near vision. And for patients with bigger pupils, the larger 8.50mm viewing area can help to reduce flare and glare that may be experienced in dim illumination.
The Visionix GP Surface Analyzer
Distance -5.50 D
D-I Zone 3.95 mm
Art Optical uses the Visionix GP Surface Analyzer to verify the ADD gradient generated on the front surface of the Renovation lens. In this example a lens with a distance power of -5.50D (Lilac colored zone) has a ADD of +2.50 (green annular ring) at a distance of approximately 3mm to 3.5 mm from the GC of the lens.
Defining Lens Translation
|1 mm translation||1.5 mm translation||2 mm translation|
Visualize the position of the lens superior edge in relation to the limbus as the lens translates vertically 1.0mm, 1.5 mm and 2.0 mm. By measuring the HVID, subtracting from that value the OAD of the lens and dividing by 2 you can determine the distance from the edge of the lens to the limbus when the lens is centered on the eye.
Spec Rx: -5.75-0.75 x 65 20/20 Add +2.00 J1+
Keratometey: 44.25 (7.62)/ 44.25 @ 95
Wearing 7.65 / 9.2 / -5.25 – Single Vision Design
Design Renovation Multifocal using current GP design
Request CL Add +0.50 stronger than spec RX. Add
Lens Dispensed – Renovation (7.9) 7.65 (44.25) 9.2 -5.25 +2.50
20/20 J1 @ 16 inches
Patients wearing Spherical Design GP Single Vision Lenses can be directly fit to Renovation using the original lens fitting parameters. Occasionally, I use a single vision fitting set to trial fit patients before ordering Renovation lenses.
I have superimposed the Visionix GP Surface Analyzer graph of the front surface of the Renovation lens along with 1 mm concentric rings onto the patient’s Renovation lens.
In this example a lens with a distance power of -5.50D (Lilac colored zone) has a ADD of +2.50 (green annular ring) at a distance of approximately 3mm to 3.5 mm from the GC of the lens.
If the lens translates 1 mm vertically, how much ADD power enters into the visual axis, assuming a 3 mm pupil?
Renovation vs. Renovation-e
|BC 7.65LD 9.5 +2.50
Add +3.25D-I Zone 7.90
|BC 7.55LD 9.5 +2.25
Add +3.25D-I Zone 7.90
Back Eccentricity 0.50
Renovation-e low eccentricity base curve e=0.5. Aspheric base curve adds to multifocal effect similar to Envision design. Better fit for low to moderate toric cornea.
Renovation (left) vs. Renovation-e (right):
The ADD power = +3.25 at 3.5 mm from the GC
These are tangential topography maps taken of the lens in situ. Zone irregularity is perhaps due to tear residue on the lens surface. Due to temporal lens displacement, a simultaneous focus gradient of over 2 diopters is generated. To improve distance vision with the Reonvation-e lens, the patient has to use a slight temporal gaze to center the lens
Managing Spectacle Blur
|Refraction at no contact lens wear for 3 days
-3.50 -1.50 x 180 Add +1.75 20/15 J1+
|Refraction at contact lens removal
-2.50 -1.50 x 105 Add +1.50 20/20 J1+
GP contact lens patients often have “spectacle blur” on removal of their contact lenses. Prescribing new glasses can be problematic. Use of corneal topography along with multiple refractions allow the practitioner to better understand the patients shifting refractive needs and to prescribe the appropriated Spec. RX.
Case 2: SynergEyes® Multifocal Contact Lens
By Dr. Walter Choate
55 yo WF, plant manager, type A+ personality, husband, happy, Crystalens patient.
Dx Myopic Astigmatic Presbyopia
OD -4.00 -0.75 X 165
OS -4.00 -0.75 X 170
Near demand balanced on near and intermediate, likes 16″ reading, and intermediate 25″.
OD -4.50 / +1.75 1.9 7.5 / 8.5
OS -4.25 / +1.75 2.2 7.5 / 8.5
First Progress Evaluation
Hx Blurred Distance VA
VA OD 20 / 20 – 3 J-1
OS 20 / 30 – 1 J-1
Adjusted Rx. No change except 1.9 OZs OU
Second Progress Evaluation
Hx Blurred Distance VA
VA OD 20 / 20-3 J-1
OS 20 / 20 J-1
What have we missed ????
Pupils Photopic 2.0 mm
Scotopic 4.5 mm
The fix: hand-holding / education / great sunglasses