www.AvtLens.com! ! ! ! ! ! ! www.MyGPSolutions.com

THE AVT RC SCLERAL DIAGNOSTIC SET

Advanced Vision Technologies303-384-1111 888-393-5374

14828 West 6th Avenue, Suite 15-BGolden, CO 80401

Sponsored inpart by:

A N e w C o n c e p t I n S c l e r a l L e n s D e s i g n

!Expanded Central Sagital Zones

!Three Scleral Alignment Zones

!A Simplified Approach to Scleral Lens fittings

Adv an c e d V i s i o n Te c hno l o g i e s

18 Lens Diagnostic Fitting Set

SUPPORTING INFORMATION

14828 West 6th Avenue, Suite 15-B Golden, CO 80401

303-384-1111 888-393-5374

AVT Scleral Lenses

A Simplified Approach To Scleral Lens Fitting

Background Scleral lens fitting has been utilized primarily for the fitting of highly irregular corneas due to trauma, post surgical or genetic considerations. Until recently, very little was known about the sclera and these very large designs which placed the entire weight of the lens beyond the cornea and limbus. Traditionally over the past 20 plus years, Scleral lenses have been fit by very few Practitioners with designs that remained unchanged throughout the years. The basic designs were based on many assumptions having now been proven not absolute. Previous scleral designs incorporated parameters consisting of a central base curve and peripheral system designed to create enough sagital vault to completely clear the cornea while aligning the peripheral carrier of the lens with the sclera. Traditional thinking of the basic sclera considered the sclera to be a very flat curvature. Traditional scleral designs incorporated conventional corneal lens peripheral systems consisting of a series of flattening peripheral curves to create both alignment and edge clearance on the sclera. This traditional approach featuring optic zones routinely smaller than 8.0 mm created a necessity of excessively high sagital values to allow the lens to adequately clear the entire cornea. This high sag fitting philosophy complicated the fitting process with trapped bubbles underneath the lens due to the high clearance of the central curve and adhesion or seal off at the lens edge or the junctions of the mid peripheral system. This seal off, creates

blanching, a white appearance of the sclera inside the lens diameter caused from the decrease of blood flow to the cornea.

Traditional Thinking of the Sclera

14828 West 6th Avenue, Suite 15-B Golden, CO 80401

303-384-1111 888-393-5374

Pacific University has recently completed a large comprehensive study of the sclera. The study consisted of analyzing 48 patients, 96 eyes measuring 1536 angles. The method of measurement was having a de-centered fixation point with the Visante OCT scan. Measurements were taken in four quadrants; superior, inferior, nasal & temporal averaging the angles of the Sclera at 10.0mm to15mm, & 15mm to 20mm.

A new understanding of the sclera has been discovered in that beyond

limbus, the sclera is better defined as a tangent angle rather than a

progressively flattening radius.

The AVT Scleral Fitting System was developed

with this new understanding of the sclera; Simplifying the fitting process while

Increasing patient satisfaction and long term success Understanding the Sclera is defined as a tangent angle rather than radii. Knowing the average sclera angle is quite consistent with most eyes, a standardized Tangent Carrier System in conjunction with an increased central Optical Zone more easily effectively vaults the cornea and limbus while providing alignment with the soft conjunctiva of the sclera.

For Consultation – Call 888-393-5374 or 303-384-1111

14828 West 6th Avenue, Suite 15-B Golden, CO 80401

303-384-1111 888-393-5374

AVT Scleral Tangent Carrier Fitting System

The AVT Scleral Tangent Carrier Fitting System is designed to simplify the fitting process of scleral lenses. The Twelve lens system consists of three Central/Sagital Values (CSV) indentified as: CSV Low/40.00/8.44/Sag 3.875 --- For low elevated cornea such as oblate/Post Surgical CSV Medium/45.00/7.50/Sag 4.150 --- For average elevated most common cornea CSV High/50.00/6.75/Sag 4.350 --- For highly elevated cornea such as Keratoconic The AVT Scleral Tangent Carrier Fitting System provides each CVS with three different tangent carrier angles (TCA) indentified as: TCA Medium/Steep carrier angle --- For less peripheral lift TCA High/Standard carrier angle --- For average peripheral lift (Most Common) TCA Extra High/Flat carrier angle --- For higher peripheral lift Each CVS also has one trial lens selection with increased central sagital value due to an added steep transitional zone between the CSV and TCA. This steep transitional Zone provides increased sagital height centrally as well as more clearance over the limbus. This combination of twelve different sagital heights and tangent carrier angles create a needed combination to properly determine the alignment of the AVT Scleral lens on the majority of human eyeballs. The desired well-fit relationship of the AVT Scleral lens is to assure complete clearance of the cornea allowing no impingement of the lens surface across the cornea or limbal area. The entire weight of the lens should be resting on the sclera. The Pacific Study shows the angle of the sclera at approximately 15mm is quite consistent. The further out on the sclera the more toricity is found due to the muscles attaching to the orbital globe. There seems to be no correlation between the steepness or flatness of the cornea in relationship to the sclera. However there is a slight apparent relationship of toricity meaning when cornea exhibits a great amount of toricity the sclera often-manifest toricity. Toric applications in the peripheral carrier as well as toric optical zones can be designed and manufactured as needed.