FORM 2
THE PATENTS ACT, 1970
(Act 39 of 1970)
COMPLETE SPECIFICATIONS
(See Section 10)
Title: Novel Diffractive EDOF Intraocular Lens Name: Biotech Vision Care Pvt. Ltd. Address: Block 1, Abhishree Corporate Park,
0pp. Swagat Bungalows BRTS Stop, Bopal-Ambli Road
Ahmedabad- 380058, Gujarat, India. Nationality: Indian
The following specification particularly describes the invention and the manner in which it is to be performed.

Title of Invention
Novel Diffractive EDOF Intraocular Lens
Field of Invention
The present invention relates to Extended Depth Of Focus (EDOF) intraocular lens (IOL). More particularly, the present invention relates to development of extended depth of focus intraocular lens (EDOF IOL) by using diffraction pattern (circular groves) on the refractive lens anterior surface to provide continuous vision from far objects to intermediate objects and functional near distance objects also.
Background of the Invention
A cataract is defined as any opacification or clouding of the eye's crystalline lens. Cataracts develop slowly with a gradual decline in vision that cannot be corrected with glasses. Intraocular lenses (IOLs) are implanted in the eyes of patients during cataract surgery to replace the opacified natural crystalline lens for a corrected vision without the need of using spectacles for different visions.
Due to the popular desire for spectacle independence postoperatively, use of intraocular lens (IOL) for presbyopia correction in the setting of cataract surgery is an increasingly prevalent aspect of cataract surgery practice. IOL technology has advanced significantly over the past several decades, and an increasingly diverse set of options for IOL correction of presbyopia has become available to physicians. Multifocal Intraocular lenses are available which can be refractive or diffractive. Diffractive Multifocal IOLs provide better near vision, reading ability, and equivalent intermediate vision, reduce unwanted photic phenomena, and allow greater spectacle independence. Still, there are few problems arising in them. Due to heavy weight of the lens, the ability of the lens to adapt becomes less to size of the pupil and cause

result in blurriness and discomfort to the wearer. Thus the wearer is forced to use spectacles and thus whole utility purpose of the diffractive lenses is failed. Another important aspect of diffractive lenses is that diffractive lenses are generally used for distant vision and short distance visions. They cannot be used for intermediate vision. Hence, the user still has to depend on glasses for intermediate vision. And hence the whole concept of being independent of spectacles is failed.
Another important aspect is center ring of the Diffractive zone. Diffractive multifocal lenses having smaller center zone diameter. If patients having larger angle alpha more than 0.5mm, the visual axis of the eye passes through the diffractive zone and increase the glares in the patient eye. Hence Diffractive lenses are not suitable for larger angle alpha patients who are having more than 0.5 mm alpha value due to the smaller size of the center diffractive zone.
Thus, there is a need to develop such diffractive lenses which are more comfortable to wear to all type of cataract patients and gives a continuous vision for far, intermediate and shorter distances simultaneously without compromising the quality of vision.
Prior Arts and its disadvantages:
The prior art document US7073906B1 is a multifocal ophthalmic lens, which includes a lens element having anterior and posterior surfaces with a central aspherical refractive zone, disposed on one of the anterior and posterior surfaces; and a diffractive bifocal zone disposed outside of the aspherical refractive zone. The central aspherical refractive zone may be disposed on the anterior surface and the diffractive bifocal zone may be disposed on the posterior surface
However, the above-mentioned prior art fails to provide a continuous vision in varying lighting conditions.. Hence, it does not provide adequate vision in

dark and low lighting conditions. Consequently, it cannot be used by the wearer throughout the day.
Another prior art document US5344448 relates to a snap-together arrangement for a multi-focal lens is provided for use as an artificial lens implant in an eye from which the cataractous natural lens has been removed. The lens includes concentric lens portions secured together by an engagement arrangement to engage adjacent lens portions. Haptic members are provided to secure the lens in the eye.
However, the above-mentioned prior art does not provide any arrangement for smooth, glare free and halos free vision during change of the power while viewing distant and closer objects. Hence these lenses are prone to blurriness during change of focal distance. Therefore they fail to provide a smooth and continuous vision for changing distance and hence fail to reduce the dependency on glasses.
Summary of the Invention:
The present invention relates to intraocular lens (IOL) with extended focal depth (EDOF) by using diffraction pattern (circular groves) on the refractive lens anterior surface to provide continuous vision from far objects to intermediate objects and functional near distance objects. The main objective of the present invention Diffractive EDOF intraocular lens is Penta focal technology by adding four nearby add powers to nominal power by using Diffractive & refractive principles which further provides continuous vision more than 2.0 D depth of focus without any loss of contrast
Another objective of the present invention Diffractive EDOF intraocular lens is to provide continuous vision from far distance to intermediate distance and also up to functional near distances for daily activities without being dependent on the glasses.

Further objective of the present invention Novel Diffractive EDOF intraocular lens is to allow the patients to have smaller incision during surgery, which ultimately results in faster recovery and minimal scars.
Another objective of the present invention Diffractive EDOF intraocular lens is to provide 2.0 D extended depth of focus with good contrast which further enables an improved vision.
Another objective of the present invention Novel Diffractive EDOF intraocular lens is to minimize the haloes by providing sufficient spacing between concentric circular diffractive zones and hence give a crystal clear vision.
Yet another objective of the present invention Novel Diffractive EDOF intraocular lens is to minimize the glare by smoothening out the diffractive groves with the provision of curvature at the sharp edges.
Another objective of the present invention Novel Diffractive EDOF intraocular lens is to allow larger angle alpha [around 0.8 mm] of the patients by providing larger diameter at the center diffractive circular grove (1.7mm diameter). The larger diameter of the center ring (around 1.7 mm diameter] further allows the larger angle alpha patients, which is otherwise problematic for other diffractive multifocal IOLs
Yet another objective of the present invention Novel Diffractive EDOF intraocular (IOL) lens is the optimized energy distribution at each add power to provide continuous vision and good contrast in all light conditions (photopic & scotopic conditions].
These and other objects of the invention will be appreciated by reference to the drawings of the invention and to the detailed description of the preferred embodiment that follow, it being understood that not all objects are

necessarily simultaneously attained by each aspect of the invention, and that not all objects are necessarily fulfilled by each claim of the application.
Brief description of the Drawings:
Figure 1 represents the anterior surface of the present invention.
Figure 2 represents the posterior surface of the present invention.
Figure 3 describes the concentric annular diffractive rings/zones in the accordance with the present invention.
Figure 4 describes about the cross sectional view of the present invention.
Figure 5 describes about the posterior surface square edge of present invention.
Figure 6 explains about the optical output result (autofocus scan) in accordance with the present invention.
Detailed Description of the present invention along with the drawings:
The following paragraphs describe preferred embodiments of the device according to the present invention. The claimed subject matter is described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. It will be obvious to a person of ordinary skill in the art will be aware that the activities described are only exemplary and several variations are possible, all of which are understood to fall within the scope of this disclosure. Moreover, the drawings may not be to scale. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of present invention. Any benefits, advantages, or solution to problems that are described herein with regard to specific embodiments are not intended to be construed as a critical, required or essential feature or element of any or all the claims.

The terms 'IOL', 'intraocular lens', 'lens' are used in same sense in the complete text of this document and may be taken as same for the purpose of disclosing the invention herein.
The terms 'EDOF', 'extended depth of focus', are used in same sense in the complete text of this document and may be taken as same for the purpose of disclosing the invention herein.
The following paragraph describes about the design of novel extended depth of focus Intraocular lens (EDOF INTRAOCULAR LENS] in accordance with the present invention and its outcomes and advantages due to the design. The claimed subject matter is explained with the drawings at required places, where in like reference numerals are used.
The present invention of intraocular lens is called extended depth of focus intraocular lens [EDOF IOL). The present invention offers clear vision from far distance to intermediate distance and functional near vision for daily activities like driving, cocking, computer & laptop usage.
The present invention novel Diffractive extended depth of focus intraocular lens is related to intraocular lenses, which are used in the cataract surgery for replacement of the natural crystalline lens. This novel diffractive EDOF lens in accordance with the present invention is developed with hydrophobic acrylic material having the refractive index of 1.52. The design in accordance with the present invention is suitable with the materials like Hydrophilic & Hydrophobic having the range of refractive index higher than aqueous humour like from 1.4 to 1.55 the refractive index. The EDOF intraocular lens design in accordance with the present invention is having single piece structure as described in the figure 1. It shows the front surface of the intraocular lens, which is called as anterior surface of the innovation. The part number 101 represents the center optic portion of the intraocular lens,

which is responsible for the light ray refraction & diffraction inside the eye and part number 102 & part number 103 represents the modified C type haptics of the intraocular lens. The figure 2 represents the back surface of the intraocular lens device, which surface is called as Posterior surface of the intraocular lens. The posterior surface center optic portion represented with the part numbers 104, which is having single radius of curvature on the entire posterior optic surface and part number 105 and 106 represents the haptics of the intraocular lens device in accordance with the present invention.
The center optic portion of the intraocular lens is having the innovative design to provide extended depth of focus to see the objects from far distance to intermediate distance and functional near vision. As depicted in Figure 3, the center optic portion is having 13 concentric circular diffractive rings on the refractive surface on the anterior surface part 107 in accordance with the present invention. The outer peripheral zone shows the refractive surface as shown in the part number 108 in the figure 3.
The Diffractive EDOF property is achieved based on the principle of Diffraction & Refraction. In the diffraction pattern, four nearby add powers are added to the nominal power of the IOL in accordance with the present invention. Hence the technology is called as Penta focal technology by adding four nearby add powers to nominal power by using unique Diffractive & refractive aspheric design in accordance with the present invention.
The diffractive surface adds multifocal property to the IOL in accordance with the present invention. Objects at infinity are focused to the same paraxial focus as a conventional IOL of the same nominal power. Objects at intermediate and functional near distances are also focused to the same point. The intermediate, functional near distances and the relative intensities of the multi foci are design parameters.

In accordance with the present invention, the multi-focal property is achieved with annular, concentric diffractive zones each with the same axially symmetric surface profile. Each zone is displaced along the optical axis from the adjacent smaller zone by the same distance along with each zone surface area is optimized to achieve sufficient intensities. Consequently the width of each annular zone is less than the width of smaller zones in accordance with the present invention. The difference in power between the multiple foci is a function of the area of the zones. The intensity ratio between the multiple foci is a function of the axial displacement between zones. Ie. The zone/ring area provides the power of the foci and the height of the zone/ring provides the intensity.
The outer diffractive zones have increasingly smaller width and it would be impossible to machine zones right out to the edge of an IOL. For this reasons the diffractive zones do not cover the entire surface of the IOL. The zone outside the diffractive zones is larger and different which can be assigned any [single] power. The present invention has the same power as the nominal lens power.
The diameter Di of annular diffractive zone i is given by

The displacement S (step height) between zones is described as


nIOL is refractive index of the lens material
Where p is the ratio between relative intensity at far and foci.
The width of the grove will provide the add power and height of the grove will contribute the energy at particular add power. In accordance with the present invention's design 4 different optimized add powers are given to nominal power (Penta focal technology) to provide continuous vision around 2.0 D depth of focus with good contrast. The larger diameter of the center ring can allow the larger angle alpha patients, which is problematic for the diffractive multifocal IOLs.
The present invention of Novel Diffractive EDOF intraocular lens having 13.0 mm overall size and 6.0 mm diameter of optic portion. In accordance with the present invention the Diffractive pattern is limited up to 5.0 mm diameter on the anterior side and peripheral refractive zone is left for distance vision in low light condition as shown in part number 108 in the figure 3. The 5.0 mm Diffractive zone having 13 number of concentric circular groves with optimized spacing between the rings to reduce the glares. The lens surface in accordance with the present invention has negative spherical aberration to balance the corneal positive aberration. The optimized diffractive zone diameter can provide different add powers and provide continuous vision. The curved edges of groves/rings as shown in the cross sectional view of the Figure 4 cross section A-A and the zoomed view B part numbers 109, 110, 111 & 112 can control the halos and glares and minimize those effects in night light condition. The posterior surface having 360-degree square edge to prevent the early PCO (Posterior Capsular Opacification] as shown in the figure 5 part number 113.

Design specifications of the present invention:
In the design and development of the present invention Novel Diffractive EDOF IOL, Hydrophobic material was used and it was having the refractive index of material 1.524. The design is suitable with the materials like Hydrophilic & Hydrophobic having the range of refractive index higher than aqueous humour like from 1.4 to 1.55 the refractive index. The size of the optic portion is 6 mm and the overall diameter of the IOL is 13.0 mm. These lenses having diopter range from 05.0 D to 40.0 D with a 0.5 D step increment with more than 2.0 D extended depth of field.
Specifications:
Optical Material: Hydrophobic
 Refractive Index: 1.524. [The design is suitable with the materials like
Hydrophilic & Hydrophobic having the range of refractive index
higher than aqueous humour like from 1.4 to 1.55 the refractive
index).
 Optic Surface: Aspheric
 Overall size: 13.0 mm
 Optical Size of the IOL: 6 mm
 Number of concentric diffractive circular groves: 13 (number can
vary as per requirement and add powers]
Results of the present invention:
The present invention of the Novel Diffractive EDOF IOL gives satisfactory results on the optical bench performance. Continuous and extended depth of field is observed in the autofocus scan measurement (Modulation Transfer Function curve) by using monochromatic light wavelength around 546 nm.

The Modulation Transfer Function (MTF) curve in the Figure 6 shows the achieved EDOF property of the IOL at 3 mm aperture size. The MTF curve representing more than 2.0 D depth of field. The maximum achieved intensity at nominal power is more than 0.30 MTF_50 line/mm and the entire range of 2.0 D depth of field having around 0.20 MTF _50 line/mm.
Thus, the achieved depth of field is useful to see the objects from far distance to intermediate distance and functional near objects, which covers the arm's length distance for daily activities. Moreover, Novel Diffractive EDOF intraocular lens allows the patients to have smaller incision during surgery, which ultimately results in faster recovery and minimal scars.
The following description is of the best-contemplated mode of carrying out the invention. The description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense.
Claims:
We Claim:
1. Novel Diffractive EDOF INTRAOCULAR LENS which is shaped so as to be assemblable into an assembled state in situ in a capsular bag of human eye so as to have extended depth of focus as well as see the objects from far distance to Intermediate distance and functional near which covers the arm's length distance also for daily activities comprising of
Light rays passing through the Novel Diffractive EDOF INTRAOCULAR LENS made of hydrophobic shape retaining synthetic material with refractive index

material of at least 1.5 (The design is suitable with the materials like Hydrophilic & Hydrophobic having the range of refractive index higher than aqueous humour like from 1.4 to 1.55 refractive index).
a posterior segment having single radius of curvature on the entire posterior optic surface 104 and the haptic 105,106
anterior segment 101, which is responsible for the light ray refraction & diffraction inside the eye and the modified C type hapticsl02, and 103 kept IOL stable inside the eye;
center optic portion having at least thirteen concentric circular diffractive rings on the refractive surface on the anterior surface as shown in part 107;
the difference in power between the multiple foci is a function of the area of
the zones;
the intensity ratio between the multiple foci is a function of the axial
displacement between zones;
the outer peripheral zone shows the refractive surface 108 and the lens
surface in accordance with the present invention has negative spherical
aberration to balance the corneal positive aberration.
diffractive pattern is limited up to 5.0 mm diameter on the anterior side and peripheral refractive zone is left for distance vision in low light condition
and curved edges of groves/rings 109, 110, 111 & 112 can control the halos and glares and minimize those effects in night light condition along with the posterior surface having 360 degree square edge to prevent the early PCO (Posterior Capsular Opacification).
2. Novel Diffractive EDOF INTRAOCULAR LENS of claim 1, wherein the size of the optic portion is 6 mm and the overall diameter of the INTRAOCULAR LENS is 13.0 mm.

3. Novel Diffractive EDOF INTRAOCULAR LENS of claim 1, wherein the center optic portion having thirteen concentric circular diffractive rings on the refractive surface with optimized spacing between the rings to reduce the glares.
4. The concentric circular diffractive rings of claim 1, wherein the width of each zone is less than the width of smaller zones and each zone is displaced along the optical axis from the adjacent smaller zone by the same distance along with each zone surface area is optimized to achieve sufficient intensities.
5. The outer diffractive zones of claim 1, have increasingly smaller width and it would be impossible to machine zones right out to the edge of an IOL.
6. The diffractive zones of claim 1, do not cover the entire surface of the IOL and the zone outside the diffractive zones is larger and different which can be assigned any (single) power
7. Novel Diffractive EDOF INTRAOCULAR LENS of claim 1, wherein the lens surface has negative spherical aberration to balance the corneal positive aberration.
8. Novel Diffractive EDOF INTRAOCULAR LENS of claim 1 optimized diffractive zone diameter can provide different add powers and provide continuous vision.