What s a Corneal GP Lens?

Transcription

1 Slide 1 What s a Corneal GP Lens? Richard Dorer NCLEC Blanchard Contact Lens Inc x 131 richarddorer@gmail.com Slide 2 Endorsements I am a paid representative and consultant of Blanchard Contact Lens. I represent Blanchard Contact Lens in the Mid- Western United States. Slide 3 1. Good Vision Benefits of GP Lenses Automatically corrects most astigmatism Excellent optical quality Good surface wettability Good bifocal lens designs 2. Excellent Eye Health On average 2-3 times more oxygen provided to the cornea as compared to most soft lenses Smaller size allows tear exchange and debris removal Fewer deposits due to surface wettability 3. Durability GP lenses last longer and don't need to be replaced as often as soft lenses Lower long-term cost 4. Ease of Handling Smaller size lenses are easier to insert 5. Ease of Care Simple cleaning and disinfecting systems can be used due to wettable surfaces and deposit-resistant surfaces Lower annual cost 6. Slow Down Myopia Progression Studies have shown that GP lenses slow down myopia progression in young people

2 Slide 4 Benefits of GP Lenses Provide Many Management Options Spherical Lenses Highly Astigmatic Lenses Presbyopic Lenses Keratoconus Lenses Slide 5 Key Requirements for RGP Materials Oxygen permeability Predictable fitting Wettability Deposit resistance Visual acuity Stability durability Slide 6 Where do the Corneal Lenses Go? Lenses are supported by the cornea and a thin tear layer. The Lids are what Feels the edge. Once a lens is worn for 1-2 weeks patients usually don t experience Lens Awareness

3 Slide 7 Insertion / Removal Slide 8 Video of Insertion and removal Make the video Slide 9 Spherical GP Lenses Rotate Spherical GP lenses always rotate nasal This is a function of the blink. When you blink our eye lids do not go straight down they act in a scissor motion. This and the teeter-totter effect help keep debris from under the lens.

4 Slide 10 Evolution of GP Lenses PMMA Non-Breathing Plastic Silicone Acrylate Boston II, PP02 Fluoro Silicone Acrylate Equalens, FluoroPerm 30, 60, 92 Aercore Chemistry Boston ES, Boston XO Silicone Hydrogel Onsi 56, Hybrid FS Slide 11 Traditional Backbone PMMA based - Dk = 0 Chains pack together tightly O CH3 O CH3O O O OCH 3 O O CH 3 Slide 12 AERCOR Polymer Backbone Chains are spaced O O O O O O O O Oxygen permeability without silicon provides Dk = 15 from the backbone alone

5 Slide 13 Base Curve Parts of a GP Lens Secondary & Peripheral Curves Optical Zone Peripheral / Secondary Curves Edge Profile Diameter Overall Lens Diameter (Uses lids to control lens) Slide 14 A base curve is utilized in the proper fitting of a contact lens. This is in direct relation to the patients K readings. Base Curve Base Curve Slide 15 When reading the base curve only the central portion is used. (Read) Base Curve

6 Slide 16 The overall diameter is from outside edge to outside edge. This enables the lids to help position the lens on certain designs. Diameter Lens Diameter Slide 17 Optical Zone Diameter The optical zone is where all the usable optics are for the lens. Outside of this area is know as the peripheral area. Slide 18 Intermediate / Peripheral Curves Intermediate and peripheral curves manage the way the GP lenses perform on the eye. Changes in the base and secondary / peripheral curves will effect the fit. Intermediate & Peripheral Curves

7 Slide 19 Intermediate / Peripheral Curves Intermediate and peripheral curves manage the way the GP lenses perform on the eye. Changes in the base and secondary / peripheral curves will effect the fit. Slide 20 Intermediate / Peripheral Curves Intermediate and peripheral curves manage the way the GP lenses perform on the eye. Changes in the base and secondary / peripheral curves will effect the fit. Slide 21 Secondary / Peripheral Curves Blending the curves makes the lens more comfortable

8 Slide 22 Slide 23 The edge profile is very important to the overall comfort of the GP lens. This is the part of the lens that a patient will notice as awareness. Edge Profile Edge Profile Slide 24 It is very important to have a good rounded edge. Enhances comfort Decreases Lens Awareness Edge Profile

9 Slide 25 Front Curve The power of a GP lens is derived mainly from the front curve. The base curve also plays a part in the lens power. Front Curve Slide 26 Types of Single Vision GP Designs Spherical Aspheric Toric Front Surface Toric Back Surface Toric Bi-Toric Kerataconous Slide 27

10 Slide 28 Evaluating RGP Lenses Containing UV Blockers BLOCKED FLUORESCENCE = PSEUDOSTEEP PATTERN Slide 29 Slide 30 Monovision Contact Lenses This is the most common and the oldest form of Bi-focal contact lenses. Traditional Monovision Uses spherical lenses (one eye for near & one for distance) Modified Monovision Uses sphere in dominant eye and bi / multifocal for the other Modified Bifocal Uses bifocal in both eyes however, one eye is for distance and the other is for near

11 Slide 31 Bifocal / Multifocal RGP Designs Aspheric Executive Crescent Concentric Fused Flat-top Multi-aspheric Slide 32 ALTERNATING VISION Slide 33 Executive GP Bifocals are very effective when a patient has a critical near demand. No Intermediate Vision Uses prism to keep position Very thick and bulky Uncomfortable Bifocal / Multifocal RGP Designs

12 Slide 34 Crescent GP Bifocals are very effective when a patient has a critical near demand. No Intermediate Vision Uses prism to keep position Very thick and bulky Uncomfortable Bifocal / Multifocal RGP Designs Slide 35 Bifocal / Multifocal RGP Designs Fused Flat Top bifocals are made from fusing a different index plastic in-to a carrier button. Good near vision. No Intermediate Vision Uses prism to keep position Thinner than Executive and Crescent Bifocals Uncomfortable Slide 36 Concentric Bifocals are the least used of these types of GP lenses. Near vision is located in the center of the lens. No Intermediate Vision Bifocal / Multifocal RGP Designs

13 Slide 37 Bifocal / Multifocal RGP Designs This is the first generation of Multifocals Usually fit 2 to 4 diopters steeper than flat K Corneal molding and spectacle blur is a major issue Cannot achieve high ADD powers Slide 38 Bifocal / Multifocal RGP Designs Next generation of Aspheric Multifocals. The Blanchard Essential GP Multifocal is a great example. Fit more along a corneal alignment fitting philosophy Very thin and comfortable More ADD available than other aspheric multifocals Slide 39 Bifocal / Multifocal RGP Designs The Essential CSA GP Multifocal is the newest style of GP Multifocals. This lens offers all the benefits of aspheric multifocal lenses and executive bifocal lenses. More ADD is capable in this design because of the addition of Concentric S- Form Add placed on the front of the lens.

14 Slide 40 CSA Enhancement Concentric S-Form ADD Slide 41 CSA Enhancement Concentric S-Form ADD How It Works Distance Optics Intermediate Optics Near Optics CSA Enhancement for Supplemental ADD Concentric S-Form Aspheric Multifocal Optics Slide 42 HOW IT WORKS IN PRIMARY GAZE, THE PATIENT IS MAINLY LOOKING THROUGH THE CENTER OF THE LENS (DISTANCE CORRECTION).

15 Slide 43 PRIMARY GAZE LENS POSITIONING Slide 44 HOW IT WORKS WHEN READING, CONVERGENCE COUPLED WITH A SLIGHT UPWARD TRANSITION OF THE LENS, FAVORS THE UTILIZATION OF THE MORE CONVEX POWERS ON THE PERIPHERY OF THE LENS, CREATING THE DESIRED MULTIFOCAL EFFECT. Slide 45 READING TASK LENS POSITIONING

16 Slide 46 IMPORTANT NOTE IN ORDER TO MAXIMIZE THE ADD AVAILABLE IN EACH SERIES, THE LENS NEEDS TO TRANSLATE UPWARD ALONG THE VERTICAL MERIDIAN AS THE PATIENT LOOKS FROM DISTANCE TO READING TASKS. AN UPPER LID ATTACHMENT WILL FACILITATE THE UPWARD TRANSITION OF THE LENS. Slide 47 BLANCHARD ESSENTIAL RGP Slide MM 9.5MM 10.0MM

17 Slide 49 SERIES I SERIES II SERIES III Slide MM 7.70MM 7.80MM Slide 51 ESSENTIAL RGP BCR=7.50 mm Too flat BCR=7.40 mm Acceptable flat fit

18 Slide 52 ESSENTIAL RGP BCR=7.30 mm Acceptable steep fit BCR=7.20 mm Too steep Slide 53 BLANCHARD ESSENTIAL RGP X X Slide 54 FITTING Best to use diagnostic lenses Fitting Calculators Obtain manufacturer s fitting guides designs vary greatly between manufacturers Selection of initial lens Each manufacturer has own recc. starting point

19 Slide 55 Questions?