GB2401954A - Contact lens with channels and holes - Google Patents

Abstract

An extreme angled, channelled and fenestrated contact lens, manufactured from any material, has holes angled at equal to or greater than 70{ to the visual axis or pole of the lens. Each drill hole has an entry channel (I) and an exit channel (III). Three or more such holes may be present. Tunnel (II) is shown. The entry and exit channel can be straight or fanned to give maximum passage of tears liquid. The holes may be processed by drilling, laser drilling or heat pierced. The holes may be formed using preformed rods e.g. of acrylate embedded in a hydrophilic button which would drop out when the hydrophilic material expands during hydration.

Description

MEMBRANE LENS - PHASE ONE

Campbell McKay Taylor SOFT CONTACT LENS WITH CHANNELS AND HOLES.

The invention comprises a contact lens of any material, hard, gas permeable, s^-mi soft, soft, nylon, silicone, silicone sheathed in hydrophilic, sterilized biological, sterilized cloned or manufactured from any material whatsoever, with drill holes (fenestrations) processed in such a way as to pierce the lens at angles ranging from 70 degrees upwards from the optical axis of the Lens, to create tunnel fenestrations with entry and exit channels, to closely align the direction of the flow of tears liquid across the lens and eye; with the outer and inner face of the tunnelled fenestration parallel or almost parallel to the optical axis of the lens and vertical or almost vertical to the flow of tears liquid permitting maximum and direct access of tears liquid to and from the front surface of the eye.

For the purpose of this invention this combination of chann.--Ls and tunnel is referred to as a CHUNNEL.

Such chunnels are necessary to introduce fresh tears liquid to the cornea of the eye and to drain spent tears liquid therefrom; the chunnels are so formed that they will introduce and drain tears liquid to and from the chamber between the back central optic radius of the contact lens and the front surface of the eye, in whatever position the lens takes up on the eye.

The entry and exit channels may be straight or they may be fanned in order to gather or dispose of a greater quantity of tears liquid thereby increasing the efficiency of the system.

The number of chunnels, at least three and preferably more, depend on the amount of tears liquid secreted from the lacrimal gland, as deemed by the prescriber, after he or she has taken appropriate tear flow tests.

These channels effectively increase the water content of the lens since they allow a greater supply of tears liquid access to the front surface of the cornea allowing the lens to become a biological membrane, permitting access of fresh sustenance bearing tears to the eye, draining toxic bearing spent tears therefrom. When straight or slightly angled fenestrations are prescribed the flow of tears is inhibited, the tears liquid subject to evaporation and loss of quality.

S ITE OF FENESTTION POJ AS

The cornea is thinnest at the centre where most interchange of absorption and emission occurs, (See Figure 1A) therefore the chunnels are sited to guide tears liquid to a position just above the centre of the eye, and to exit spent tears from a site just below the centre of the eye, returning to the front surface just above the lower lid margin, in the relaxed eye, but so as not to interfere with vision.

DIAMETER OF HOLES

The diameter of the hole is optional but large enough to prevent blockage and to permit a good flow of tears liquid onto and out from the eye surface. Therefore 0.2 - 1.Omm diameter is ideal.

LENS MATERIAL

Chunnels are effective in all lens materials, hard PMMA methylmethacrylate, gas permeable, nylon, silicone, silicone sheathed in hydrophilic, hydrophilic, sterilized animal or cloned biological material or any material from which lenses may be Stormed. When silicone material sheathed in hydrophilic is laser drilled, drilled or heat pierced the comfort is interfered with and the walls of the tunnel are sprayed with hydrophilic material to restore full comfort.

DEFINITIONS:

BACK CENTRAL OPTIC RADIUS

Radius of the back central portion of a contact lens.

BLANK

Sometimes referred to as a button, this is a small cylinder of any material from which a contact lens is formed.

CANALICULUS.

Each canaliculus consists of a vertical portion of about 2mm long and then bends inward for some 8mm, pierce the covering of the lacrimal sac and enter the sinus of Maier thence to the inferior meatus of the nose.

CHUNNL

Chunnel comprises an entry channel a tunnel fenestration and an exit channel, passing superiorly from the front surface of the lens to the back surface and inferiorly from the back surface of the lens to the front surface. The face of each tunnel fenestration is vertical or nearly vertical to the flow of tears liquid, parallel or nearly parallel to the optical axis of the lens.

CORNEA

The transparent anterior portion of the fibrous coat of the globe of the eye [See figures 1 and 2]. The Cornea is avascular, receiving its nourishment by permeation through spaces between the lamellae. Sources of nourishment are the aqueous humour, tears liquid and the limbal (peripheral) capillaries.

The cornea owes its transparency to the regular arrangement of the collagen fibres, but any factor which affects this lattice structure (eg swelling, pressure) results in loss of transparency. Chunnels are formed in a radial pattern and cause minimal interference with vision, since they emulate the regular arrangement of the collegan fibres.

EQUATORIAL PLANE

The plane which is perpendicular to the optical axis.

FENESTRATION

A hole formed on a lens for the purpose of the passage of tears in or out, to or from the surface of the eye.

LIMBUS OF THE CORNEA

The transitional zone lam wide between the conjunctive + sclera and the cornea [See figure 1]

OPTICAL AXIS

The line normal to the surfaces of a lens along which light will pass undeviated.

PUNCTUM

Each punctum is a small round or oval aperture situated on a slight elevation at the inner edge (Nasal) end of the upper and lower lid margin and forms the entry to the canalliculi.

STIRRER

heated stirring device which revolves contact lenses in a basket cleaning process with a vortex effect.

TEARS

Contain nutrients and other beneficial products.

HISTORICAL NOTES

Fenestrated (drilled and countersunk) contact lenses are not new, first suggested by Norman Bier Patent number GB592055 No 2049/45 utilised in the wear of large Haptic or Scleral lenses' which covered most of the front eye surface, such fenestrations cleared up many of the earlier problems with these large hard lenses.

Experimenting with early soft lenses the inventor attempted fenestrations (drilling and countersinking holes) as early as 1962, introducing a fenestrated bifocal contact lens, operating on a surface tear retention system at an international conference in 1964. latent application GB 12849/65 in 1965 was applied for by agents Cruikshanks and Fairweather but not pursued, due to variations of the bifocal effectivity.

Patent EP0698802A1 1995 utilises the fame methodology.

In a lecture to the Scottish Conference in 1976 the inventor introduced a lens formed by a plurality of fenestration holes (see note 2) Fish net perma lens. "The advantages of fenestraLing soft contact lenses"' (See note 3) was introduced at al-n international contact lens conference published in British journal Optician' and American journal Contacto' in 1979.

Fenestrations were also utilised in ''A fenestrated system in kerataconus" Optometry Today 1994 (see note 4).

Patents US3246941, (1966) Moss; FR2741727 A 19970530 (1997) Elie; US6010219 (04.01.2000) N. Stoyan; and WO 02/27388 Al (04.04.2002) R.Andino; all have vertical fenestration parallel i or only slightly angled from the optical axis of the lens whereas the unique monopoly of the present invention is that the chunnels are formed by angles between 70 degrees or more from the optical axis so as to closely approximate parallelism with the flow of tears liquid (see figure 4b and 5) permitting access from the lacrimal gland directly to the surface of the eye, and direct drainage of spent tears liquid from the eye to the drainage system.

INTRODUCTION

Tests indicate that certain beneficial elements pass into the eye by topical means. Borne across the front eye surface by Lears liquid secreted from the lacrimal gland, sited under the eyelids and from the eyelid margins thereafter absorbed into the eye by a flow largely created by thermal attraction; the relatively higher internal eye temperature when compared to the extraneous temperature in normal conditions.

Tears liquid contain many substances which are beneficial to the continued health of the eye.

The cornea is thinner at the centre, approximately 0.57mm, approximately 0.7mm at 20 degrees from the centre (see Figure 1A), thickening towards the periphery. It is therefore likely that greater topical interchange takes place near the centre of the cornea.

When contact lenses are fitted this normal function is interfered with and side effects sometimes develop; the normal passage of tears liquid is hampered, tears liquid evaporate in warm conditions.

Reversal of the process can occur drawing moisture from the soft lens and eventually from the front surface of the eye. Therefore instead of the lens passing fluid on to and into the Cornea the flow of fluid i; reversed and moisture is drawn from the front surface of the eye causing dry eye syndrome, there is also a dangler that spent tears containing toxic matter are reabsorbed into the eye inducing a dangerous situation; thus the NATURAL

FLOW ACROSS THE SURFACE OF THE EYE FROM THE LACRIMAL GLAND TO

THE DRAINS AT THE PUNCTA IS INTERFERED WITH AND MAY BE REVERSED.

Natural processes undergo a change to rectify these problems in order to pump oxygen and beneficial elements into the eye and neovascularization occurs - new blood vessels form at the limbus, the border between the cornea and the sclera, such new vessels grow into the cornea.

In the past the inventor has experimented with low water content material and a plurality of fenestrations (drill holes) which alleviated the problem of neovascularization (See enclosed paper 2).

The fenestrations were sited in a radial formation in the mid peripheral area half way between the centre and the edge of the lens.

DOWNTHRUST

However when such lenses were used to sleep in overnight, the 2 am syndrome, the drying of the eye around two in the morning, caused some discomfort. This was due to the down thrust of the mass of the lens material causing an upthrust of tears liquid on the surface of the eye causing a risk of abrasion of the corneal cells due to the resulting suction effect see illustration (Figure 2). By altering the angle of the fenestrations to become chunnels this problem is overcome since the passage of tears to and from the eye surface follow the natural process of the flow of tears liquid.

INCREASED EFFECT OF UPTHRUST IN PMMA AND GAS PERMEABLE LENSES

Chunnels are very effective with PMMA or gas permeable material.

When fenestrated the down thrust of material and upthrust through the fenestration holes can cause abrasion and the back optic radius of the lens has to be steepened to avert this risk.

this compensation can have an adverse effect on the visual efficiency of the system.

No such compensation is required with chunnels since downthrust of the material causing upthrust through the fenestration holes is minimal. l

SUCKBACK EFFECT.

A further problem experienced with straight and slightly angled fenestrations was SUCK BACK.

Suckback occurs with straight or slightly angled fenestration holes. Spent tears, containing toxic matter emitted from the eye, is sucked to the front surface of the contact lens, fed back through the fenestration and reabsorbed into the eye.

The channel lens obviates both downthrust and suckback since the chunnels are at right angles to the optical axis of the lens the normal directional flow of tears is maximal, downthrust of the lens material is minimal, upthrust through the fenestration holes is also minimal; suck back is no more possible than toxic material flowing against the flow of a river in spate.

Down thrust of lens material and upthrust from the eye increases as the lens material hardens, greatest in methylmethacrylate material or gaspermeable material or very low water content hydrophilic material, a plurality of channels solves these problems in such lenses.

By minimizing the effects of upthrust and suckback chunnels have larger fenestration holes of 0.2 - lam which, in turn, reduce the build up of protein, calcium and carbon deposits.

A plurality of chunnel holes allows the lens to rotate during wear and ensures fresh tear liquid entry superiorly and stale l tear exit inferiorly.

It is also probable that the eye lid epitheliums being slightly roughened have a polishing effect on the cornea which smooths the corneal epitheliums (See figure 2) after prolonged soft lens wear fluorescein staining reveals a roughened surface. This is thought to be caused by the surface cells being protected from the eyelid polishing process; the slight abrasive effect of the grooves of the chunnel lens obviate this problem.

TECHNICAL DETAILS

Holes are drilled, laser drilled or heat pierced on a dehydrated contact lens blank button at a wide angle from the vertical axis of the blank button. The hydrophilic button is drilled to conform to the requisite angles. Swarf is removed by air suction. Fenestrations are usually performed on dehydrated lens material and although heat piercing on hydrated finished soft lenses is feasible, the lens requires dehydration prior to the polishing process.

Polishing of the fenestration may be carried out by various methods. One suggested method is to syringe the holes under pressure with a mixture of minuscule shreds of cloth and water soluble polish allowing the paste to form a plug, the vortex effect when the lens is processed in a stirrer dissolves the plug, polishing the inner walls of the fenestration hole in so ( doing.

Another method is polishing the chunnels with a thread impregnated with appropriate polish; alternatively any of the other historically proven methods.

PREFORMED RODS

Chunnels can be formed by utilizing rods preformed to emulate the requisite fenestrations.

In one embodiment acrylate rods are embedded in a hydrophilic button remaining throughout the cutting and polishing process but would drop out when the hydrophilic material expands during hydration.

In a further embodiment acrylate rods are embedded in a silicone button and pressed out after processing.

Lenses formed from silicone require hydrophilic spraying on the lens surfaces and chunnels to provide acceptable comfort.

After such processing clean chunnels are achieved in the final lens.

DAILY INTERCHANGE METHOD OF CONTINUOUS WEAR

Although continuous wear is not advocated with the chunnel lens, a further development of the concept is embodied in proposed patent, Membrane Lens Phase 2, which combined with the proposed patent on Accessories should give uninterrupted continuous wear with complete safety, comfort and visual efficiency. However overnight wear in practically every case is feasible with the Chunnel lens.

The great advantage with constant wear is that critical time in the morning when everything is gal go/ go! One can spring out of bed and see perfectly for breakfast anal unhindered for that trip to towel without extra demands on a tight schedule. At mid day or evening one is more relaxed so lenses can be taken out and cleaned.

The discipline of constant wear is enhanced by a system of leap frogging with two sets of identical lenses; one pair in wears one pair soaking! cleaning and disinfecting in the case. It is just a matter of changing over and clean lenses are in situs

DRAWINGS AND ILLUSTRATIONS

Figure 1A shows the relative thinning of the cornea over the central surface area of the eye. The cornea is thinner at the centre, approximately 0.57mm, about 0.7mm at 20 degrees from the centre, thickening towards the periphery.

Figure 1 depicts part of the human eye referred to in the application: Showing the almost parallel central area of the CORNEA, the ANTERIOR CHAMBER, ANGLE of the ANTERIOR CHAMBER, where the drainage channels of the eye are situated, the contractile IRIS, behind which WATERY FLUID FORMS, the CRYSTALLINE LENS, the outer fibrous coat termed the SCLERA, the VITREOUS JELLY, the inner lining of the eye - the RETINA, and the OPTIC NERVE where bundles of wire like nerves pass from the eye to the brain.

(vii) shows the optical axis of the eye and (viii) the equatorial plane at right angles to the optical axis.

Figure 2 shows the various sections of the cornea starting with (i) the collective surface epitheliums, comprising the basal cells which grow from the basement membrane above (ii)Bowman's flattening as they approach the surface of the cornea and are called superficial cells.

(iii) Represents the STROMA of the cornea historically referred to as the SUBSTANTIA PROPRIA.

(iv) shows the site of DESCEMET'S MEMBRANE, (v) shows the inner ENDOTHELIUM.

Figure 3 shows a normal fenestration hole; such holes are made by heat piercing, laser drilling or machine drilling, countersunk and polished and are normally formed at right angles to the equatorial plane, perpendicular to the eye surface, or slightly angled therefrom.

This figure also illustrates the down thrust caused by the lens material and the upthrust through a fenestration hole. The effect of such upthrust is greatest in hard or stable contact lenses; upthrust is less in a lens of soft material due to the flexibility of the material and reduces further when the number of fenestration holes are increased.

But comfort increases markedly when fenestrations are angled from 70 to angles greater than 90 degrees becoming channels.

Figure 4a and 4b give a comparison between a normal fenestration, an angled fenestration hole and a chunnel.

Figure 4a (vii) shows the optical axis of the lens and (viii) the equatorial plane at right angles to the optical axis.

Figure 4b shows a chunnel depicted by (i) the entry channel, (ii) the tunnel and (iii) the exit channel; the angled fenestration is shown on the right hand side.

Figure 5 illustrates the Chunnel Lens, the chunnels occur when the fenestrations are angled at 70 to greater than 90 degrees from the optical axis (vii) of the lens or parallel or nearly parallel to the optical equator (viii). This means that the tunnel face of the fenestration hole is parallel or almost parallel to the optical axis (vii) and at or nearly at right angles to the flow of tears liquid l (viii) thus exerting the minimum upthrust on the eye surface causing virtually no suction effect thereon.

The Chunnel comprises (i) an entry channel which leads into the Chunnel blending into (ii) a tunnel at the exit of which there is (iii) an exit channel.

The upper Chunnel leads from the front surface of the soft contact lens, tunnels through the material of the lens then channels on to the front surface of the cornea on the surface of the eye.

The lower channel guides spent tears away from the eye, through (iv) which drains tears liquid from the eye through (v) a tunnel into an outer surface channel (vi).

Figure 6 shows the flow of tears from (i) the lacrimal gland curving (iv) across the surface of the eye to drain through (v) the puncta.

Although generally curving across the eye the tears liquid move in a slightly zig-zag manner due to the blinking of the eye lids followed by gravity drop. This allows nutritious bearing tears to pause at the apex so that interchange between ocular absorption of the beneficial elements and the emission of waste occurs. Movement of the lens whilst blinking emulates this. (ii) represents the upper eye lid margin and (iii) represents the lower eye lid margin; (iv) the meibomium and the accessory sebacious glands, on the lid margins, which secrete oily fluids; these oily fluids float on top of the tear film reducing evaporation of the tears. Tears contain salts, bipolymers, proteins, glycoproteins, urea glucose and oxygen, which are partially absorbed into the cornea and deeper layers of the eye. (

Carbon dioxide and waste products are emitted from the eye and are contained in the lower tears which are thence drained from the eye.

Figure 7 represents the chunnels in plan. These chunnels are seen to swivel on the eye but position to admit the flow of tears liquid through a superior entrance (i) to the cornea and nadir exits (ii) therefrom helping to guide the tears on their natural course.

This is supported by evidence of the passage of fluorescein dye instilled on the superior surface of a Chunnel lens. The dye flows across the outer surface, enters the upper chunnel, crosses the front surface of the cornea and drains through the nadir chunnel, emulating the natural passage of tears liquid.

Figure 8 shows the cylindrical blank (sometimes referred to as a button) which is shaped to form a contact lens by lathing. Arrows show the direction of the drilled holes positioned at a maximum angle from the optical axis of 70 to greater than 90; the resulting bores of the fenestrations pass through the centre of the blank and emerge on the other side below the centre of the cylindrical blank, entering the upper blank at 1/3 depth and exiting at 2/3rd depth, for example, these sites can be varied.

Figure 8A illustrates the lens cut from the button with the positions of the channels. The channels can be angled from 70 to greater than degrees from the optical axis of the eye (Figures I, 4a and 5 vii) Figure 9 shows fenestration holes which exceed 90 degrees from the Optical axis of the lens. Such angles increase the effectivity of the chunnel principle, since they closely align the flow of tears liquid..

Figure 10 Illustrates the increased effectivity of the entry and exit channels when fanning is processed; achieved by oscillating a drill, laser drill, heat piercing device or any other means. Subsequent polishing blends the grooving, providing comfort in wear. (S

Claims (1)

1. A fenestrated contact lens comprising: a lens body adapted for placement adjacent to the surface of an eye said lens body having an inner and outer surface, with channels and holes (fenestrations) processed in such a way as to pierce the contact lens at extreme angles ranging from 70 - to well beyond 90 degrees from the optical axis or pole of the surfaces of the contact lens in order to facilitate the natural flow of lacrimal tears liquid and other beneficial fluids secreted from the lacrimal glands, sebaceous glands and eyelids, to the said eye and after interchange from absorbed beneficial elements to discharged toxic elements, the draining away therefrom.

   fhe extreme angled, channelled and fenestrated contact lens of claim 1 includes tunnel fenestrations with entry and exit channels, the fenestrations and channels forming a so called chunnel. The chunnel is therefore a combination of an entry channel, a hole through the lens and an exit channel. The chunnel provides entry of tears liquid from the front surface of the lens to the chamber between the lens and the eye and the drainage of spent tears liquid therefrom. In

   The extreme angled, channelled and fenestrated contact lens of claim 1 necessitates the inclusion of from 3 to a radiating plurality of such extreme angled chunnels so that on rotation of the contact lens chunnels are adjacent to the incoming flow and the outgoing flow of tears liquid.

   The extreme angled, channelled and fenestrated contact lens of claim 1 comprising a contact lens with a plurality of chunnels, at least three and preferably more, each of which comprises an outer channel leading to a hole which tunnels through the lens material forming an outer and inner face which are vertical or nearly vertical to the flow of tears liquid and parallel or nearly parallel to the optical axis of the lens, leading to a channel on the inner surface of the lens; so that tears liquid is passed directly, without deviation, from the outer surface of the lens to the chamber between the lens and the eye with minimum evaporation.

   The extreme angled, channelled and fenestrated contact lens of claim 1 is so constructed to carry sustenance bearing fresh tears liquid directly, without deviation, from the outer surface f of the lens, just under the eyelid margin, through the lens, to the chamber between the back lens surface and the front surface of the eye with minimal risk of evaporation, to the apical area of the cornea where the maximum interchange of fresh tears liquid and spent tears liquid occurs. Thence passing spent tears directly to the drainage system of the eye.

   The extreme angled, channelled and fenestrated contact lens of claim 1 permits a large aperture of hole size ranging from 0.2mm to 1.Omm and therefore minimises blockage caused by carbon, calcium protein and other debris.

   The extreme angled, channelled and fenestrated contact lens of claim 1 although highly polished, there is still a slight abrasive effect from the grooves or fanning of the of the channels which emulate the polishing effect of the eye lids when blinking thus maintaining the high polish necessary for the health of the cornea.

   The extreme angled, channelled and fenestrated contact lens of claim 1 which may be of any material used in the manufacture of contact lenses: Comprising methylmethacrylate, gas permeable, nylon, silicone, silicone sheathed in hydrophilic, hydrophilic, bovine biological or cloned biological, or any other material; the effectivity of the chunnel increases relative to the hardness of the material.

   The extreme angled, channelled and fenestrated contact lens of claim having the face of the fenestration lying parallel or almost parallel to the visual axis or polar axis of the said lens and perpendicular to the equatorial plane of the said lens produces no down thrust of lens material and upthrust through the fenestration hole causing risk of abrasion rendering the fitting of PMMA methylmethacrylate contact lenses or gas permeable contact lenses both safe and comfortable with minimal compensations; normal fenestrations or slightly angled fenestration require steepening of the inner optical curve and the creation of a deep chamber between the back optic radius of the lens and the front optical radius of the eye, which can produce visual distortions.

   A further unique monopoly of the invention is introducing a button containing rods of a different material, creating a combined button which may be of methylmethacrylate combined with hydrophilic or silicone or a mixture of any materials used in the manufacture of contact lenses.

   led as follows d entS to the claims have

   A fenestrated contact lens comprising a lens body having inner and outer surfaces of at least three channels and holes (fenestrations) piercing both surfaces at an angle of at least degrees from its optical axis characterized in that the holes are formed in the side of a blank prior to cutting the lens The contact lens of claim 1 where fenestrated contact lenses are manufactured with holes having diameters of 0.2mm to l.Omm.

   The contact lens of claim 1 where fenestrated contact lenses can be made of any material used in the manufacture, comprising methylmethacrylate, gas permeable, nylon, silicone sheathed in hydrophilic or hydrophilic.

   The contact lens of claim 1 where fenestrated contact lenses channels or holes are processed by drilling, laser drilling or heat piercing.