DESC:
FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

Complete Specification
(See section 10 and rule 13)

1.Title of the Invention :

EXTENDED DEPTH OF FOCUS HIGH DEFINITION INTRA OCULAR LENS

2. Applicant Name : Appasamy Associates

Nationality : Indian

Address : No.20, 1st Street, SBI Officer's Colony,

P.H.Road, Arumbakkam, Chennai-600106

3. Preamble to the Description :

The following specification particularly describes the invention and the manner in which it is to be performed.

Description
Field of the invention
This invention relates to the field of cataract surgery which involves implantation of an intra-ocular lens (IOL) as a replacement for the Cataractous Natural Lens that is removed.
Background of the invention
Monofocal IOL are most commonly used as a replacement for the natural lens that is removed after a Cataract surgery. These lens offer a fixed focus for one distance. The surgeon may select a near focus, Intermediate and distant focus IOL. One of these is used during the surgery and the focus will not change after surgery. Traditionally, cataract surgery will provide focus of both eyes for distant objects. The patient is required to use reading glasses to see near objects.
Multifocal intraocular lenses provide an almost perfect vision, independent of the focal length. However, there is no guarantee that the multi focal implant will do away with the requirement of using reading glasses. While multifocal IOLs allow less dependence on reading glasses as compared to monofocal IOLs, multifocal IOLs may also present other challenges.
Depending on the size of the pupils, a person may see glare or halos after the implant of a multifocal IOL. The halos can create a distracting ghost image and the brain through a process called neural adaptation, learns to selectively ignore this with passage of time.
Currently available multifocal IOLs do not afford the luxury of both clear distance vision and clear reading vision because of the loss of Contrast.
To overcome this problem, the invention discloses a posterior chamber, foldable IOL manufactured with Hydrophobic acrylic natural yellow chromophore that may be implanted after extraction of a Human Eye cataract in a Phacoemulsification Surgery. The uniqueness of the design of this IOL lies on the anterior surface of its Optics, wherein two separate zones are created to facilitate the implanted patient to visualize distinctly the near objects, intermediate objects as well as distant objects.
Extended depth of focus high definition Lens
While monofocal lens have Single radius of curvature for distance vision, this invention proposes the + 3.5 D addition of a Near radius on the centre portion of 1.5mm in the optical zone of the anterior side. Due to this provision, the patient will get the near vision the rest of the optical zone will cater the need of the intermediate and distance vision. This allows the patient to be independent of spectacles at most of the times during the day today activities.
Another aspect of the invention, proposes the use of a 360 degree enhanced square edge which is added in the equatorial side in the IOL optic. This helps to prevent the PCO Posterior Capsular opacification. This enhanced square edge provides an excellent shrink wrap effect of the IOL equator with the equator of the Capsular bag around a 360 degree which completely blocks cell proliferation from the equator to the central optical zone of the capsular bag thus eliminating the chances of a PCO - Posterior Capsular Opacification which is usually caused during the naturally happening Capsular fibrosis process during any Post Cataract Surgery to fixate the IOL in its designated effective lens position in place of the extracted natural crystalline lens.
Summary of the invention
The invention is a posterior chamber IOL manufactured with Hydrophobic acrylic natural yellow chromophore material and is a foldable intra ocular lens implanted after extraction of a Human Eye cataract performing a Phacoemulsification Surgery, through a smaller incision size of 2.8mm or a 2.2mm in the Clear cornea. The lens is made of a natural yellow chromophore hydrophobic material. This is to prevent the incidence of blue rays (blue light 400 to 480 nm) from sunlight. Yellow tinted intraocular lenses (IOLs) protect the retina more effectively against blue light damage than clear IOLs.
The uniqueness in its design lies on the anterior surface of its Optics wherein two separate zones are created to facilitate the implanted Patient to visualize distinctly the Near objects, Intermediate objects and as well as a distant Object too. This provides the Patient with a perfect functional vision to suit the current technological advancement in the Human life style.
The central zone of 1.5mm diameter which has a +3.5 D add power to cater the need of near vision.
Spherical power of 3.5 dioptres as the Patient's Eye converges to focus the objects placed at a closer distance of 33cm and rest of the optical zone will cater to the need for the intermediate distance at 66 cm and light rays from distant objects at a distance of 6 metres. The light rays reflected from objects within this distance range are focussed on the Retina with the Differential vergence phenomenon of the Human Eye structure. This provides the Patient a facility to accommodate immediately to focus the near objects instantly with the help of this Central zone.
When the light rays hits on the 0.3 micron dipped down edge of this central zone there is an inward bend of the beam thereby eliminating scattering of light. Most of the light energy is bent at the 0.3 micron edge curve of the central zone. This totally eliminates the Glare for the Patient. From 1.3mm to the rest of the optical surface up to 4.75mm diameter the refractive spherical power of the IOL is designed to provide the intermediate and distance vision focussing the light rays from the distant objects. The peripheral 1.25mm forms as a square edge equator for an excellent Capsular Shrink wrap process during fibrosis.
In order to obtain the above functionality of the Extended depth of focus high definition Intra ocular lens, the pupil size of the Patient's Eye is a limiting factor which has to be 1.5mm size to 4mm pupil size under normal lighting conditions for better performance of the above said functionality.
3.0 mm pupil : 16% , 2.0 mm pupil : 36%, 1.5 mm pupil : 64% is recommended for a perfect near vision and the criteria for the distance vision is with the following size against the percentage of light entry through the IOL optics is indicated as 5 mm pupil : 94%, 4 mm pupil = 91%, 3 mm pupil = 84%.
The depth cut in the circular central 1.3 mm zone is of 10 microns height which is fixed for the Extended depth of focus high definition IOL and its smooth edge curved to facilitate effective bending of the Light rays without any reflection component. The central zone ADD power tolerance ranges between 3.2 Dioptres to 3. 5 Dioptres.
The advantages of this new optical design are :
Crystal Clear distance vision
Minimal / No halos around lights
No loss of contrast
Acceptable near and intermediate vision which improves the functional visual ability.
EDOF (Extended Depth Of Focus) technology provided to the Patient which is more effective when the Extended depth of focus high definition IOL is implanted Bi-Laterally as the brain adapts to the Stereoscopic vision much faster as the functionality of this IOL adds up to the way in which light rays reflected from near, intermediate and distant objects entering the Pupillary zone in both the Eyes will be in similar phenomenon without much of any difference in the percentage.
The following graph explains the function of this IOL optics with respect to the light energy.

Inference:
Green graph: As the Pupillary diameter increases it facilitates more Parallel light energy from distant objects to enter the outer Zone of the Extended depth of focus high definition Optics thus enhancing the distant vision and intermediate vision capability and the RED graph indicates that the percentage of light entry through the central zone drops down as there is an increase in the Pupillary diameter hence the near vision is slightly compromised with larger pupil more than 4mm. With a pupil size anywhere in between 1.5mm to 3mm the Percentage of Light entry from the near, intermediate as well as distance is almost equally distributed between the two zones thus enhancing the intermediate and distance vision also.
This newly designed optics - Infocus IOL eliminates the visual disturbances of a diffractive multifocal optic design providing the excellent near, intermediate and distance vision without compromising for the Contrast sensitivity and at the same time with quick brain adaptation when it is implanted bilaterally within a time period of one week to two weeks ( Implantation of Extended depth of focus high definition Intra ocular lens in both Eyes of same Patient ) which provides an excellent Extended depth of focus from +1.5D to -2 D subjective acceptance of the Patients subjected to the visual acuity test against the snellen's visual acuity chart. This test revealed a wide spectrum of flat zone in the defocus curves plotted for different subjects examined. This IOL also provides improved contrast sensitivity minus the Glare and halos at different lighting conditions facilitating the Patients with excellent driving comfort during night times too.
Description of Drawings
Fig. 1 : Front view of the Extended depth of focus high definition IOL
Fig. 2 : Back view of the Extended depth of focus high definition IOL
Fig. 3 : Side view of the Extended depth of focus high definition IOL
Fig. 4 : Side view of the Extended depth of focus high definition IOL with dimensions of the radii of curvature in millimetres
Fig 5 : Overview of the Extended depth of focus high definition IOL
Fig 6 : Perspective view of the Extended depth of focus high definition IOL
Fig 7 : Close-up view of the Extended depth of focus high definition IOL depicting the enhanced square edge

Senthil Kumar B

Agent for the applicant
IN/PA-1549

,CLAIMS:CLAIMS

We Claim:
1. A posterior chamber, foldable Extended depth of Focus high definition Intra Ocular Lens (IOL) manufactured with Hydrophobic acrylic natural yellow chromophore for implantation after extraction of a Human eye cataract in a Phacoemulsification surgery, comprising:
a. Creation of two separate zones on the anterior surface of the IOL, wherein a new Near radius on the centre portion of the optic is provided in addition to the surrounding optic providing a radius for intermediate and distance vision;
b. Such two separate zones allowing the patient to get such functional vision and allowing the patient to be independent of spectacles at most times.
2. The invention as claimed in claim 1, further comprising a 360 degree enhanced square edge at the equator of the IOL to prevent Posterior Capsular Opacification (PCO), wherein such square edge provides an excellent shrink wrap effect of the IOL equator with the equator of the Capsular bag around a 360 degree which completely blocks cell proliferation from the equator to the central optical zone of the capsular bag thus eliminating the chances of a PCO.
3. The invention as claimed in claim 2, wherein:
a. a central zone of about 1.30 mm diameter having nano optics with a smooth dipped down edge of 0.3 micron is provided to cater to the need of near vision with an ADD Spherical power of + 3.5 dioptres as the Patient's Eye converges to focus the objects placed at a closer distance of 33cm;
b. a mid periphery and peripheral zone comprising the area from 1.31mm diameter to the rest of the optical surface upto 4.75mm diameter, the refractive spherical power of the IOL is designed to provide the intermediate vision at 66cm along with a 6m and above distance vision focussing the light rays from the distant objects;
c. and wherein, when the light rays hits on the smooth edged 0.3 micron dipped down of this central zone there is an inward bending of the beam thereby eliminating scattering of light totally which avoids the Glare and halos for the Patient thereby, improving the Contrast sensitivity to a greater extent.
4. The invention as claimed in claim 3, wherein the high functionality of the Extended depth of focus high definition Intra ocular lens is attained for Patient’s with pupil size between 1.5mm to 4mm under normal lighting conditions.
5. The invention as claimed in claim 3, wherein, the Extended depth of focus IOL eliminates the visual disturbances of a diffractive multifocal optic design providing excellent near, intermediate and distance vision without compromising on the Contrast sensitivity and at the same time with quick brain adaptation when it is implanted in both Eyes of same Patient within a period of about 1 to 2 weeks.
6. A method of providing Extended depth of focus with a high definition IOL manufactured with Hydrophobic acrylic natural yellow chromophore for implantation after extraction of a Human eye cataract in a Phacoemulsification surgery, comprising:
a. such IOL comprising two separate zones, wherein a new Near radius on the centre portion of the optic is provided in addition to the surrounding optic providing a radius of curvature for intermediate and distance vision;
b. and wherein such two separate zones allow the patient to get a functional vision and allowing the patient to be independent of spectacles at most times.

Senthil Kumar B
Agent for the applicant
IN/PA-1549