ES2406606B1 - CONTACT LENSES AS AN INTEGRAL SOLUTION TO QUERATOCONO. - Google Patents

Abstract

Contact lenses as an integral solution to keratoconus. # The invention relates to contact lenses for use in irregular corneas and corneal ectasias comprising: # (i) an anterior surface; and # (ii) a posterior surface with a spherical central zone and an aspherical annular zone located around the spherical central zone; # characterized in that the base radius is between 5.50 and 9.00 mm, said spherical central zone has a diameter between 3.00 and 12.00 mm, the eccentricity of the aspheric ring area between 0.2 and 1.6, and the central spherical area forming a tear meniscus between 1 o and 120 microns, and the annular area Aspherical tear menisci between 20 and 150 microns.

Description

CONTACT LENSES AS A COMPREHENSIVE SOLUTION TO QUERATOCONO

FIELD OF THE INVENTION

The invention relates, in general, to contact lenses, more particularly to contact lenses for use in irregular corneas and corneal ectasias (keratoconus, marginally grafted degeneration, ...), as a treatment for improving visual quality in these patients. .

BACKGROUND OF THE INVENTION

The human visual system consists of three main components, the cornea, the lens and the retina. It is called emetropia, the ideal visual condition, so that the eye without effort or without the help of lenses, manages to converge by light refraction focusing them right on the retina, in this way the eye transmits through the optic nerve to the brain a Sharp image for correct vision. In myopia, parallel light rays are focused before the retina resulting in a blurred image. In farsightedness, parallel rays focus on a place after the retina resulting in an out-of-focus image again. Other refractive anomalies such as astigmatism and presbyopia also result in blurred images. To correct the aforementioned refractive defects it is possible to resort to the use of lenses either in the form of glasses or contact lenses or refractive surgery. Keratoconus consists of protrusion and progressive thinning of the cornea. Its clinical presentation includes myopia and / or astigmatism, progressive topographic changes, progressive corneal thinning and, normally, loss of corrected visual acuity. The most common ectasias are keratoconus and pellucid marginal degeneration (DMP). Keratoconus is a degenerative, non-inflammatory deformation of a part of the cornea, which is identified by a protrusion and corneal thinning with loss of resistance and the presence of structural changes in the corneal stroma.

The cornea has a high curvature in the apex with irregular astigmatism according to the degree of affection and a marked flattening in the peripheral area, with a gradual comeal loss of the perception of the shape. The disease usually begins in the second or third decade of life, progresses rapidly and evolves until approximately 45 years where it usually remains stable. The greater the evolution, the greater the loss of vision. A keratoconus / corneal ectasia patient is a chronic patient who, from the manifestation of the disease, will always need clinical help and revisions to improve his visual quality and therefore his quality of life. There is statistical information in Spain that confirms the existence of 1 patient keratoconus / corneal ectasia per 2,000 inhabitants. In the evolution of keratoconus there are a series of changes that have been classified in groups from I to IV according to the degree of dystrophy achieved: In grade I keratometric readings usually vary from 7.60 to 7.20 mm, there is no distortion in the sights, corneal astigmatism is oblique and less than 2.00, with the ophthalmoscope may appear shadows of slight peripheral flattening, the best visual acuity does not exceed 0.8. In grade II the keratometer reading drops to 6.90 mm with more marked shadows, astigmatism, also oblique, is greater than 3.00 D, with moderate deformation of the sights, the ophthalmoscopic reflex shows peripheral flattening shadows and The transparency of the cornea is normal, visual acuity does not reach 0.5. In grade III the readings are between 7.80 and 6.70 mm and the corneal thickness is markedly reduced. The irregular reflex indicates an important conical protrusion, there is no leucoma but in the central part vertical striations of the Descemet membrane are observed, which indicates the infiltration value of aqueous humor in the stroma. The visual acuity is 0.2. In grade IV irregular cornea readings vary between 7.50 and 5.60 mm. It is an acute keratoconus and appears after a hydrops, the distortion of the sights is very noticeable, walleye are observed in the pupillary area as a result of the filtration in the stoma of the aqueous humor that has passed through the endothelium producing ruptures in the membrane of Descemet. In some cases the corneal protrusion prevents a correction with contact lenses so the treatment must be surgical. Currently, the options for treating these conditions include the use of: Standard contact lenses that, especially those of gas permeable material,

They offer a remarkable improvement in vision quality.

Surgical methods, such as intrastromal rings that shape the

cornea internally and would slow the progression of keratoconus.

Corneal CrossLinking CCL: external procedure with UV light and riboflavin. Standard contact lenses allow optical corrections to be obtained by placing a rigid or soft material on the cornea. However, in many cases they are not a solution to the underlying condition and can be annoying to the user, especially in advanced stages. The correction of refractive defects is also achieved by surgical methods either for the remodeling of the cornea surface or for the implantation of corrective lenses. The boom experienced by refractive surgery in recent years has not been without controversy as to the complications that could appear in the medium term in the operated eyes. One of the main characteristics of corneal subtractive laser excimer surgery (PRK, LASEK, EpiLASIK or LASIK) is to produce a weakening of the corneal architecture that can lead to the development of a corneal ectasia of the posterior aspect of the cornea. Therefore, surgical methods have the normal disadvantages and risks in these types of invasive techniques, and they can also have side effects yet to be determined. The need therefore remains to find methods for the treatment of these pathologies that allow overcoming some of the aforementioned inconveniences, allowing an improvement in the quality of life of patients.

SUMMARY OF THE INVENTION

The inventors have now developed a contact lens for the treatment of the mentioned diseases, especially for the treatment of keratoconus, corneal ectasias and other irregularities derived from refractive surgery. The lens has a special design with areas of alignment of specific dimensions, forming a balance of pressures on the corneal surface and a typical fluorogram (tear meniscus) that makes them especially suitable for clinical adaptation in a patient. The lenses allow to obtain the following results:

Eliminations of high order aberrations.

Increased vision quality, both visual acuity and sensitivity in contrast Greater comfort in clinical adaptation to the patient.

The invention is directed to a contact lens for the treatment of corneal ametropia comprising:

(

i) a previous surface; Y

(ii)

a posterior surface with a spherical central zone (also known as the optical zone) and an aspherical annular zone located around the spherical central zone;

characterized in that the base radius is between 5.50 and 9.00 mm, said spherical central zone has a diameter between 3.00 and 12.00 mm, the eccentricity of the aspherical annular zone being between 0.2 and 1 , 6, and forming the central spherical area a tear meniscus of between 1 O and 120 microns, and the aspheric annular area of lacrimal menisci between 20 and 150 microns.

DESCRIPTION OF THE FIGURES Figure 1: illustrates the profile of a normal cornea, where the pressure and tension forces keep the cornea in balance. Figure 2: Illustrates the profile of a cornea with keratoconus. The intraocular pressure exceeds the tension of the cornea, producing protrusion. Figure 3: shows how a permeable lens reinforces the corneal tension producing balance. Figure 4: Lens profile with central zone and two annular zones surrounding the central zone.

DETAILED DESCRIPTION OF THE INVENTION

In a particular embodiment, said aspherical annular zone comprises bands of variable eccentricity, whose eccentricity is independently selected between the values 0.2 and 1, 6. In another particular embodiment, the aspherical annular zone comprises 3 bands whose eccentricity is different in each band. In another particular embodiment, the aspherical annular zone comprises 4 bands whose eccentricity is different in each band.

In another particular embodiment, the contact lens comprises a peripheral annular zone that surrounds the aspherical annular zone and wherein said peripheral annular zone that surrounds the aspherical annular zone is adapted to act as scleral support. The lens of the invention may be of the rigid gas permeable type, whose materials are known. See for example, Efron, Nathan, Contact lens practice. Butterworth-Heinemann Elsevier, Oxford 2010; p 145-197. The lens of the invention can be soft. This lens is indicated in patients who do not support the use of rigid gas permeable lenses. In this case, the material for its manufacture can be selected, for example, from hydrogels, silicone hydrogels and hybrid lenses. The contact lenses of the invention admit multiple materials and the person skilled in the art can determine in each case which one is more appropriate. According to a preferred embodiment, the material from which the lens is formed has an oxygen permeability (Dk) of between 30 and 250 barrers, as measured in accordance with ES 2 166 882 T3, page 15. according to a particular embodiment, the total diameter of the lens is between 8.00 and 20.00 mm. In another particular embodiment said total diameter is between 8.50 and 12.00 mm, preferably between 8.60 and 11.00 mm, more preferably between 9.00 and 10.60 mm. In another particular embodiment, the total diameter of the lens is between 8.60 and 10.50 mm, preferably between 8.70 and 10.00 mm. In another particular embodiment, the total diameter of the lens is between 10.00 and 20.00 mm, preferably between 10.60 and 18.50 mm. In another particular embodiment, the total diameter of the lens is between 11.00 and 19.00 mm, preferably between 12.00 and 19.00 mm, more preferably between 13.00 and 18.50 mm. According to a particular embodiment, said diameter of the spherical central zone is between 3.50 and 11.00 mm. In another particular embodiment, said diameter of the spherical central zone is between 3.50 and 8.00 mm, preferably between 3.50 and 6.50 mm. In another particular embodiment, said diameter of the spherical central zone is between 4.00 and 10.00 mm. In another particular embodiment, said diameter of the spherical central zone is between 4.50 and 10.00 mm. In another particular embodiment, said diameter of the spherical central zone is between 4.00 and 8.00 mm.

For the measurement of the tear meniscus, a Magellan Mapper ™ from Nidek Technologies has been used, which has been calibrated following the manufacturer's instructions. Following the manufacturer's instructions, the corneal topography of the subject has been performed and the measurements obtained from the Magellan Mapper ™ have been taken. For more information on corneal topography and meniscus measurement, see Villa, César. Atlas of corneal topography and ocular aberrometry. National College of OpticiansOptometrists, D.L. . Madrid 2004; pg 76-87; or Ming Wang. Corneal topography in the wavefront era: a guide for clinical application. SLACK Inc. Thorofare, NJ 2006; pg 69-97.

EXAMPLES

The lenses of the invention have been made following the usual methods in this field until reaching the desired dimensions. Two general methods for its preparation are described below.

Method A: WHITE LENSES (high hydro gel and low hydration). Double turning

1st.-Internal Face Block and Cut. The tacos are blocked with inserts and wax in the centering. With the tacos locked in the inserts, they were placed on the lathe to cut the inner face. The insert plug was peeled off, to polish the inner face and bands. 2nd.-Internal Face Polishing. Once the internal face was cut, the insert was placed with the block in the polisher, the appropriate polisher was chosen and a few drops of polish were cast, the internal face was polished. Once polished, the belt polisher was chosen and the soft ones polished. He cleaned the block with paper and controlled the polishing with the magnifying glass: -If the polishing was not correct, it was polished again. -If the polishing was correct, the radius was checked on the radioscopy. -If the radio was not correct and could be corrected, it was polished again. -If the radio was not correct and could not be corrected, it was discarded. -If the radio was correct, the next operation was continued. 3rd.-External Face Lock and Cut.

The thickness of the block was checked with the spectrometer. In the tool for cutting the external face, wax was applied to block the block on its internal face. It was placed on the axis of the volume and focused manually. In the volume of cut of external face the necessary data were introduced to realize the cut, controlling with the magnifying glass, that this was correct. When the cut was correct, the tool was removed with the lens, to perform the following operation.

4th.- External Face Polishing.

The tool was taken with the lens, a few drops of polish were cast and the external face polisher was molded. The tool was placed with the lens on the axis of the polisher, polish was cast on the polisher, this was placed on the lens and allowed to polish. The tool was removed, placed in the CN polisher and polished. Then it was removed to perform the following operation.

5th.- Unlocking.

The tool was introduced with the lens in the ultrasound bath, and the lens was peeled off. Be He cleaned the lens and controlled the power in the front lens. -If the power was not correct but could be reprocessed, the operation was performed timely. -If the power was not correct and could not be reprocessed, it was discarded. -If the power was correct, the following operation was performed.

6th.-Edge Polishing and Cleaning.

The lens was glued and centered on the edge tool with double-sided adhesive tape, placed on the axis of the touch-up unit and the edge polished with sandpaper. With a cloth and polish, he rubbed a few seconds. Then the edges and polishing were controlled with the magnifying glass. The lens was cleaned with paper and Baltane. 7th.-Hydration. The clean lens was left hydrating for 12 hours (approximately) in individual jars with saline solution.

so.-Final Control.

The lens was removed from the hydration bottle and controlled the diameter, thickness, cosmetic and radio in the projector; the power in the front lensmeter. -If the lens did not meet specifications, it was discarded. -If the lens met specifications, the following operation was performed.

9th.-Sterilization.

The clean vial was placed, with saline solution, the hydrated lens was cleaned in the ultrasound bath and placed in the vial. The silicone cap, the capsule was placed and placed in the autoclave tray, to sterilize. Once sterilized, the following operation was performed.

Method B: RGP-HYBRID LENSES. Double turning 1st.-Locking and Internal Face Cutting.

The tacos were blocked with inserts and wax in the centering. With the tacos locked in the inserts, it was placed in the volume to cut the inner face. He removed the insert plug to polish the inner face and bands.

2nd.-Internal Face Polishing.

Once the inner face was cut, the insert was placed with the block in the polisher, it was chosen the right polisher and throwing a few drops of polish, the inner face was polished. A Once polished, the belt polisher was chosen and the soft ones were polished. He cleaned the block with paper and controlled the polishing with the magnifying glass. -If the polishing was not correct, it was polished again. -If the polishing was correct, the radius was checked on the radioscopy. -If the radio was not correct and could be corrected, it was polished again. -If the radio was not correct and could not be corrected, it was discarded. -If the radio was correct, continued with the next operation.

3rd.-External Face Lock and Cut.

The thickness of the block was checked with the spectrometer. In the tool for cutting the external face, wax was applied to block the block on its internal face. It was placed on the axis of the volume and focused manually. In the volume of cut of external face the necessary data were introduced to realize the cut, controlling with the magnifying glass, that this was correct. When the cut was correct, the tool was removed with the lens, to perform the following operation.

4th.- External Face Polishing.

The tool was taken with the lens, a few drops of polish were cast and the external face polisher was molded. The tool was placed with the lens on the axis of the polisher, polish was cast on the polisher, this was placed on the lens and allowed to polish. The tool was removed, placed in the CN polisher and polished. The following operation was taken out and performed.

5th.- Unlocking.

The tool was introduced with the lens in the ultrasound bath, and the lens was detached. Be

5 cleaned the lens and controlled the power in the front lensmeter. -If the power was not correct but it could be reprocessed, the timely operation was performed. -If the power was not correct and could not be reprocessed, it was discarded. -If the power was correct, the following operation was performed.

10 6th.-Edge Polishing and Cleaning. The lens was glued and centered on the edge tool with double-sided adhesive tape, placed on the axis of the touch-up unit and the edge polished with sandpaper. With a cloth and polish, he rubbed a few seconds. The edges and polishing were controlled with the magnifying glass. He cleaned the lens with paper and Solvaran.

15 7th.-Final Control. The diameter was controlled with the V-ruler, the radius in the radioscopy, the power in the front-lensmeter, the thickness in the spectrometer and the cosmetic in the backlight. -If the lens did not meet specifications, it was discarded. -If the lens met specifications, it was cleaned and performed the following operation.

20 Following the methods described above, 4 lenses have been prepared, the characteristics of which are summarized in Table 1. Each of these lenses is used for the treatment of the mentioned indications.

Table 1

Example A

Example B Example C Example D

   Indication

Correction of spherical ametropias (myopia, farsightedness), associated with corneal astigmatism up to 2 dp. Compensation keratoconus 1 grade 1 corneal ectasia (incipient) Correction of spherical ametropias (myopia, farsightedness), associated with high corneal astigmatism up to 6 dp. Compensation keratoconus 1 corneal ectasia grade 11 and 111 (medium or advanced) Correction of spherical ametropias (myopia, farsightedness), associated with high corneal astigmatism up to 6 dp. Compensation keratoconus 1 grade IV corneal ectasia (advanced) Correction of spherical ametropias (myopia, farsightedness), associated with high corneal astigmatism up to 3 dp. Compensation keratoconus 1 corneal ectasia grade 1 (incipient). Complementary application to lens adaptation

of contact in

patients with

ring implants

intrastomals

Geometry

Stero-asteric with four alignment bands Tricurva-asteric with four alignment bands with high eccentricity Multiastérica with three bands of progressive steroastic alignment and variable asteric scleral band Asteric estuary with three alignment bands

Material

RGP-high hydrogel and RGP-high hydrogel and RGP-high hydrogel and RGP-high hydrogel and

low hydration-

low hydration-

low hydration-

low hydration-

hybrid

hybrid

hybrid

hybrid

Base radio

7.00-9.00 (steps 5.50-8.50 (steps 0.05 5.50-9.00 (steps 0.05 6.00-9.00 (steps of

0.05 mm)

mm) mm) 0.05 mm)

Power

± 30.00Dp (steps ± 30.00Dp (steps 0.25 ± 30.00Dp (steps ± 30.00Dp (steps 0.25

0.25 Dp)

Dp)  0.25 Dp) Dp

Zone diameter

3.5-6.5 (steps 0.05 3.5-6.5 (steps 0.05 4.5-10.0 (steps 0.05 4.00-8.00 (steps 0.05

optics

mm) mm) mm) mm)

Total diameter

9.00-10.60 (steps 8.70-10.00 (steps 10.60-18.50 (steps 13.00-18.00 (steps

0.05 mm)

0.05 mm)

0.05 mm)

0.05 mm)

Value

0.2-1.6 (steps 0.01 0.2-1.6 (steps 0.01 0.2-1.6 (steps 0.01 0.2-1.6 (steps 0.01

sphericity

mm) mm) mm) mm)

bands

(eccentricity)

   Bandwidth

1-5 (steps 0.01 mm) 1-5 (steps 0.01 mm) 1-5 (steps 0.01 mm) 1-5 (steps 0.01 mm)

Claims (25)

l. Contact lens for the treatment of comeal ametropias that includes:

(

i) a previous surface; Y

(ii)

a posterior surface with a spherical central zone and an annular zone

aspherical located around the central spherical zone; characterized in that the base radius is between 5.50 and 9.00 mm, said spherical central zone has a diameter between 3.00 and 12.00 mm, the eccentricity of the aspherical annular zone being between 0.2 and 1 , 6, and forming the central spherical area a tear meniscus of between 1 O and 120 microns, and the aspheric annular area of lacrimal menisci between 20 and 150 microns.

2.

Contact lens according to claim 1 wherein said aspherical annular zone comprises bands of variable eccentricity, whose eccentricity is independently selected between the values 0.2 and 1, 6.

3.

Contact lens according to claim 2 in which the aspheric annular zone comprises 3 bands whose eccentricity is different in each band.

Four.

Contact lens according to claim 2 in which the aspherical annular zone comprises 4 bands whose eccentricity is different in each band.

5.

Contact lens according to any one of claims 1 to 4 which additionally comprises a peripheral annular zone surrounding the aspherical annular zone and wherein said peripheral annular zone surrounding the aspherical annular zone is adapted to act as scleral support.

6.

Contact lens according to any one of claims 1 to 5 characterized in that it is a rigid gas permeable lens.

7.

Contact lens according to any one of claims 1 to 5 characterized in that it is a soft lens.

8.

Contact lens according to claim 6 which is formed by a material selected from the group consisting of hydrogels, silicone hydrogels and hybrid lenses.

9.

Contact lens according to any of the preceding claims wherein the total diameter is between 8.00 and 20.00 mm.

10.

Contact lens according to claim 9 wherein the total diameter is between 8.50 and 12.00 mm.

eleven.

Contact lens according to claim 1 or wherein the total diameter is between 8.60 and 11.00 mm.

12.

Contact lens according to claim 11 wherein the total diameter is between 9.00 and 10.60 mm.

13.

Contact lens according to claim 9 wherein the total diameter is between 8.60 and 10.50 mm.

14.

Contact lens according to claim 13 wherein the total diameter is between 8.70 and 10.00 mm.

fifteen.

Contact lens according to claim 9 wherein the total diameter is between 10.00 and 20.00 mm.

16.

Contact lens according to claim 15 wherein the total diameter is between 10.60 and 18.50 mm.

17.

Contact lens according to claim 9 wherein the total diameter is between 11.00 and 19.00 mm.

18.

Contact lens according to claim 17 wherein the total diameter is between 12.00 and 19.00 mm.

19.

Contact lens according to claim 18 wherein the total diameter is between 13.00 and 18.50 mm.

twenty.

Contact lens according to any of the preceding claims wherein the diameter of the spherical central area is between 3.50 and 11.00 mm.

twenty-one.

Contact lens according to claim 20 wherein the diameter of the spherical central area is between 3.50 and 8.00 mm.

22

Contact lens according to claim 21 wherein the diameter of the spherical central area is between 3.50 and 6.50 mm.

2. 3.

Contact lens according to claim 20 wherein the diameter of the spherical central area is between 4.00 and 10.00 mm.

24.

Contact lens according to claim 23 wherein the diameter of the spherical central area is between 4.50 and 10.00 mm.

25.

Contact lens according to claim 23 wherein the diameter of the spherical central area is between 4.00 and 8.00 mm.