Abstract: An ophthalmic lens is provided having a PET polarizing film integrally bonded thereto and, optionally, a hard coating integrally bonded to the PET polarizing film. In a preferred construction, the lens material may be surface treated, either physically and/or chemically, for integrally bonding the film to the lens material. Similarly, in another preferred construction, the film may be physically and/or chemically surface treated for integrally bonding a hard coating to the PET film.

Abstract: A color-enhancing polarized lens is constructed having substantially trichroic spectral-transmission. A lens so constructed may have an overall transmitted tint which is a virtually colorless gray to the eye. A lens so constructed and tint-neutralized delivers unexpectedly dramatic improvements in the areas of color saturation, chromatic and luminous contrast, clarity of detail, depth perception, haze penetration, and overall impact.

Abstract: A transparent optical material containing at least one selenium atom, a plastic lens comprising the transparent optical material, and methods for preparing them. In addition, there are also disclosed novel selenium-containing compounds represented by the following formulae (1), (2) and (4) which are useful for the transparent optical material and the plastic lens: ##STR1## wherein symbols are as defined in the specification.

Abstract: An image viewing system to permit viewing of three-dimensional images, wherein users wear a pair of eyeglasses to view displayed images. The pair of eyeglasses include lenses having LCD polarizing filters and a LCD controlling unit configured to adjust the polarization of the lenses based upon the orientation of the glasses. A sensing unit, located on the glasses, monitors the orientation of the glasses and when the orientation is skewed from a default orientation, the sensing unit notifies the controlling unit of the new orientation. Upon receipt of the new orientation, the controlling unit then initiates a change in the polarization of the LCD filters. Adjustment of the polarization allows users of 3-D viewing glasses to freely adjust head position relative to the displayed images without compromising the integrity of the viewed image.

Abstract: An improved sunglass lens laminate has first and second lens portions joined by an adhesive, wherein the adhesive at least one of (1) an ultraviolet absorber in an amount sufficient to block substantially all solar radiation up to about 400 nm, and (2) a dye to provide selected visible light transmission characteristics to the laminate. In a preferred embodiment, a polarizing film is disposed between two lens portions to form a polarizing sunglass lens laminate.

Abstract: Hinge and one or more wires, or electrical conductors, wherein portion of such wire or wires extends axially through the hollow pivot pin of a hinge and wherein such portion of the wire or wires is placed in torsion upon the hinge being pivoted.

Abstract: An ocular mounting assembly for adjustably mounting a pair of ocular devices, such as telemicroscopic loupes, to an eyeglass frame or head mount with linear and rotational adjustments, but with view angle being permanently preset in accordance with working distance. The ocular mounting assembly includes an adjustable ocular support assembly and an adjustable clamp assembly rotatably attached to the ocular support assembly. The ocular mounting assembly includes a housing and two slidable mounting arms to which the ocular devices are attached, the transverse cross-sectional shape of the housing interior and mounting arms being such that substantially all of the volume of the housing interior is consumed apart from close tolerances to facilitate the sliding motion, thus resulting in a structure which cooperates to assist in providing a substantially rigid assembly.

Abstract: A method and apparatus for reducing glare created by oncoming headlights or the sun at either dusk or dawn is disclosed. The method uses a light filter to reduce the intensity of light encountered by a driver from oncoming headlights in a region. The region is defined by the driver's side portion of the windshield and a separatrix. The separatrix includes a horizontal segment, a vertical segment, and a perspective segment. The horizontal segment is located between the driver's side portion and the passenger's side portion of the perimeter of the windshield. The horizontal segment has first and second ends such that the second end is adjacent to the driver's side portion and the first end is adjacent to the passenger's side portion. The vertical segment begins at a central position on the upper portion of the windshield and ends at the first end of the horizontal segment.

Abstract: A polarizing lens for sunglasses comprising a laminate having a polarizing thin layer and supporting layers made from polycarbonate-resin being laminated on both surfaces of the thin layer, and a method and an apparatus for producing said polarizing lens. The laminate used for the inventive polarizing lens is formed as a oblong in which polarizing axis is corresponded to the cross direction thereof, and is so curved as to have a non-spherical curved surface whose curve along the direction of polarizing axis is shaper than curve along the direction orthogonal to the polarizing axis.

Abstract: An electric connection configuration for an electro-optical device comprises a brow bar member which houses the electronics of the device, and a pair of flexible conductor tabs which attach to the electronics in the housing and extend therefrom to form electrodes for connection to the lenses. When the brow bar is attached to the frame, the conductor tabs hang over the frame and extend within the space formed by the eye openings of the frame. As the lenses are fitted into a respective eye opening, the flexible conductor tabs are folded back such that they become sandwiched between the edge of the lens and the frame. In a preferred embodiment, the flexible conductor tabs each form a positive electrode, and a pair of screws, which also serve to attach the brow bar to the frame, each form a negative electrode for attachment to a respective lens.

Abstract: A polarizing film or composite which can eliminate glare of the light reflected by an object and passing therethrough while maintaining the original color of the object. The polarizing film is color-adjusted so that the color coordinates L, a and b in the UCS color space, where L is the color brightness divided into 0 to 100 sections and in terms of tristimulus values X, Y and Z in the standard colorimetric system CIE, L=100Y.sup.1/2, a=175 (1.02X-Y) Y.sup.1/2, b=70 (Y-0.847Z) y.sup.1/2, will be 22.ltoreq.L.ltoreq.70, -2.0.ltoreq.a.ltoreq.2.0, -2.0.ltoreq.b.ltoreq.2.0, that the light transmittance in the wavelength range of 410-710 nm will be within +30% of its average, and that the light transmittance in the wavelength range of 410-750 nm will be not more than 2% when two of said polarizing films are put one upon the other so that their polarizing axes extend perpendicularly to each other.

Abstract: A pair of eyeglasses includes a focus adjusting device including an auxiliary frame formed with two lens frames, two annular ring-like wheels rotatably fitted within the two lens frames, a flexible loop member connecting the two annular ring-like wheels, two lenses fitted in the two annular ring-like wheels, an engaging plate fixedly mounted on an intermediate portion of an inner side of the auxiliary frame and provided with a hook, and a main frame provided with a pair of temples for fitting over ears of a user and having two lens frames in which are fitted two lenses, the main frame having an inner side being provided with a recess dimensioned to receive the hook of the engaging plate, whereby the eyeglasses can be adjusted to change the focus as desired.

Abstract: An article comprising substrate having a surface and a coating on the surface of the substrate, the coating comprising a fluoropolymer and a fluorochemical surfactant. The fluoropolymer and the fluorochemical surfactant are selected such that the article is anti-reflective, abrasion resistant and anti-fogging. Methods of making the same are also described.

Abstract: A lens assembly is disclosed comprising at least first and second removably superimposed eyewear elements each comprising a frame member including framing means for at least one lens. Each frame member has a first longitudinal curvature in an unassembled condition of the lens assembly, and at least the at least second eyewear element further has a flexible intermediate portion providing for longitudinal flexibility of the at least second eyewear element along a transverse medial axis thereof such that the at least second eyewear element is deformable to define a second longitudinal curvature complimentary with the first longitudinal curvature of the at least first eyewear element when the at least first and second eyewear elements are removably axially superimposed in longitudinal alignment.

Abstract: A device for selectively reducing the intensity of light in the field of view of an eye or of an optical instrument is described. The device can reduce the light intensity emanating from multiple sources. In one embodiment, an eye gear has a frame, a power source, a light sensor, two light transmissive lenses having an array of shutter elements, user controls and processing circuitry. The user controls are utilized to set user constants to customize the apparatus, and may be used to select a mode of operation. During operation, the light sensor scans the field of view and produces light intensity signals. These light intensity signals are processed with the user constants and preset threshold values. If the light intensity signals exceed any of the threshold values, then one or more elements of the shutter matrices of each lens is darkened.

Abstract: A variable density light-polarizing spectacles apparatus comprising a frame having right and left lens carrier portions, a bridge portion, and rearwardly directed temples for supporting the spectacles apparatus before the eyes of the wearer. Inner right and left lenses are rotatably mounted within the right and left lens carrier portions, respectively. Each inner lens has a notched portion at its periphery. A gear assembly is positioned substantially between the right and left lens carrier portions of the frame. The gear assembly meshes with the notched portion of the inner lenses to allow for the simultaneous rotation of the inner right and left lenses. The frame has an upwardly-facing opening substantially above the bridge portion. A portion of the gear assembly extends slightly beyond the upwardly facing opening of the frame to permit manual adjustment of the orientation of the inner lenses. A removable, outer lens assembly slidably engages the frame.

Abstract: A device for selectively reducing the intensity of light in the field of view of an eye or of an optical instrument is described. The device can reduce the light intensity emanating from multiple sources. In one embodiment, an eye gear has a frame, a power source, a light sensor, two light transmissive lenses having an array of shutter elements, user controls and processing circuitry. The user controls are utilized to set user constants to customize the apparatus, and may be used to select a mode of operation. During operation, the light sensor scans the field of view and produces light intensity signals. These light intensity signals are processed with the user constants and preset threshold values. If the light intensity signals exceed any of the threshold values, then one or more elements of the shutter matrices of each lens is darkened.

Abstract: A sealed, polarizing lens assembly including a frame, a first light polarizing lens element, a second light polarizing lens element superimposed with the first lens element and rotatable in relation to the first lens element. The frame and the first element define a sealed chamber in which the second element is entirely enclosed and rotatable relative to the first pair of elements. Means for rotating the second internal element in the sealed chamber relative to the first pair of elements are provided. In one form the means for rotating the internal element in the seal chamber comprise a sealed gearing mechanism with user-accessible external actuators. The sealed, easily-adjusted lens assembly of the invention prevents contamination of internal lens surfaces by dust and moisture, for example. The seal chamber can also be provided with a fluid or gas with desired optical or thermal barrier characteristics.

Abstract: An electrochromic device for use in the field of optical lenses. The device includes a substrate having an expanse and an edge region. A first electrode layer is coated on the expanse and extends substantially across the expanse and into the edge region. An electrochromic layer is coated on the first electrode so that the first electrode layer physically isolates the electrochromic layer from the substrate. A second electrode layer is coated on the electrochromic layer, so that the electrochromic layer physically isolates the second electrode layer from the first electrode layer. A first contact is electrically connected to the first electrode layer. An isolative barrier is coated on the first electrode layer in the edge region. A second contact is electrically connected to the second electrode layer. Alternatively, an isolative channel is formed in the second electrode layer to electrically isolate the first electrode layer from the second electrode layer.

Abstract: A lens structure and electronic control system is provided for use in eyeglasses. The lens structure is formed by a pair of lenses with a transmission layer formed by an electro-optic material is disposed therebetween. The transmission layer is used to control the amount of light that is transmitted through the lens structure by placement of a variable voltage placed across it. The transmission layer can be formed by either a dichroic dye or by a ferro-electric material such as PLZT. The electronic control system uses a photoamperic sensor placed behind the lens structure to develop a current proportional to the transmitted light. The current is converted into a voltage which is compared to a desired transmission range. If the sensed transmission level is outside the desired range the control circuit causes a power supply to add or decrease the charge across the lens as necessary to bring the transmitted light level back into the desired range.

Abstract: The invention concerns photochromic compounds with general formula (I): ##STR1## where R.sup.a, R.sup.b and R.sup.c represent hydrogen; alkyl, aryl, OR, SR, COR or COOR, where R represents hydrogen, alkyl or aryl, amino with formula NR.sub.1 R.sub.2, where R.sub.1 and R.sub.2 each represent hydrogen, alkyl, cycloalkyl, or aryl, R.sub.1 and R.sub.2 may together form a heterocycle containing four to seven members with the nitrogen atom and may intracyclically contain one or more heteroatoms selected from nitrogen, oxygen, sulphur, or a halogen atom; a mono- or polyhaloalkyl; an NO.sub.

Abstract: It is a pair of glasses capable of producing a 3-D visual effect, mainly including a frame, two polarizing lenses set in the frame, and two additional lanminated lenses removably disposed either in front of or behind the two polarizing lenses. The laminated lenses each consists of two glass sheet layers, an LCD layer between the two glass sheet layers, and a polarizer layer attached to an outer side of one of the two glass sheet layers. When a voltage is applied to the LCD layer, molecules constituting the LCD layer rotate and change their arrangement directions to produce light blocking effect, enabling the glasses to be used as an LCD shutter glass for watching a 3-D image system. When the additional laminated lenses are removed, the glasses can be used as a normal sun glass.

Abstract: The optical instrument comprises at least one lens (5) and application means (9) for applying the optical device. The lens is constituted at least in part by a liquid crystal device (LCD); power supply means of regulable voltage (11) are provided, to control the transparency of the lens.

Abstract: Sunglasses are provided wherein each lens opening has a fixed polarized lens and a rotatable polarized lens. A slide is carried by the frame, with each rotatable lens being connected thereto at locations outside of the lens openings. Lateral movement of the slide effects the rotation of the rotatable lenses, thereby varying the transitivity of the sunglasses.

Abstract: A combination lens assembly having optical properties suitable for use in eyewear comprising a glass lens member and a plastic lens member having a rim for holding the glass lens proximate thereto.

Abstract: In a preferred embodiment, glasses or spectacles of identical polarized lenses have an additional matching pair of detachably mountable separate other identical polarized lenses variably rotatable to vary intensity of the polarized light when intermittently mounted by insertion past depressable resilient locking structure and dismountable by withdrawing past the depressable resilient locking barrier structure.

Abstract: A light transmission adjustable spectacle structure comprises for each lens set thereof a fixed polaroid lens and a rotatable polaroid lens which has a number of non-polarized aperture-like areas formed thereon so that when the rotatable lens is rotated relative to the fixed lens to have the polarization directions thereof normal to each other, light is only allowed to pass through the apertures of the rotatable lens. This significantly cuts down the transmission of light through the lens set. In addition, by suitably selecting the size of the aperture-like areas, the depth of focus of retinal image occurring to a wearer of the spectacles is properly increased to provide a more clear view to the wearer.

Abstract: Plastic lenses having substantially no optical power and a light-polarizing layer therein are prepared by shaping composite laminate of the light-polarizing layer between opposed sheets of thermoplastic material by heating and pressing the laminate between opposed shaping molds (platens), the platens having predetermined radii of curvature for the production of a lens having substantially no optical power. Shaping is effected under conditions of heating and pressing sufficient to cause flow of the thermoplastic sheets and conformation thereof to the respective curvatures of the forming surfaces of the platens. The lenses are especially suited as sunglass lenses for spectacles.

Abstract: An ophthalmic device comprises a frame having a pair eye apertures and first and second linearly polarizing elements fixedly or rotatably mounted in the apertures. The first and second elements each have a polarizing transmission axis and the axes are fixedly or selectively disposed at an angle of 45.degree. to 90.degree. with respect to each other.

Abstract: A light polarizing spectacle lens including a lens body and a light polarizing film embedded in the lens body. The lens body is made from a resin mixture comprising a pregelled monomer of about 65 to 75 weight percent of the mixture, a conventional monomer of about 25 to 35 weight percent of the mixture, and isopropyl carbonate of about 2.7 to 2.9 weight percent of the mixture. The polarizing film is in the form of a wafer dried at approximately 140.degree. F. to 160.degree. F. for about 2-12 hours.

Abstract: A method and apparatus for enhancing the vision of an individual viewing an object through an optical path through water. The method includes filtering the light that enters one eye of the individual to effect subtractive filtration to compensate for differential light absorption of water, and filtering light that enters the second eye of the individual which does not compensate for the differential light absorption of water. The apparatus includes two light transmitting elements, one of which filters light to effect subtractive filtration to compensate for differential light absorption by water and the other of which does not compensate for the differential absorption of light by water.

Abstract: Disclosed and claimed are a substantially hermetically sealed variable density ophthalmic device, preferably in the form of sunglasses or goggles. The device includes front and rear frame components which matingly fit and seal together. The polarized or retarder lenses include at least one pair of rotatable lenses. These lenses are preferably rotatable by a flexible strip having a knob. A grommet or boot or the combination thereof seals the interface where the strip enters a frame component.

Abstract: A lens and a pair of glasses incorporating the lens wherein each lens has first and second lens elements, preferably formed of mineral glass, with a bigradient coating deposited on the inner surface of the first lens element by a vacuum coating process. The lens elements are laminated together with a polarization film therebetween and have an anti-reflectant coating preferably on the outer surface of the second lens element. Waterproof coatings may be formed on the anti-reflectant coated outer surface of the second lens element and the outer surface of the first lens element.

Abstract: A visual aid for nighttime driving of automobiles having an exterior side mounted rear vision mirror wherein a driver tends to be subjected to headlight glare directly from oncoming automobiles and headlight glare reflected by the mirror from following automobiles, having a frame, and a supporting assembly, including a glare reduction arrangement which includes a direct glare portion and a reflected glare portion for reduction of light transmission therethrough. A lens arrangement including the glare reduction arrangement and a frame mounted blocking portion of the glare reduction arrangement may also be used.

Abstract: A pair of variable density sunglasses include two lens elements of polarized material forming each lens. The other lens element is rotatable in a channel in the frame by manipulation of a gear mounted on the nose bridge, the gear teeth being engaged with gear teeth on the edge of the outer lens element. Rotation of the gear is limited by a peg extending from the back thereof into an arcuate channel on the nose bridge. The stationary inner lens is prevented from rotation by an edge tab extending into an opening in the lens channel through which the gear and rotatable lens engage.

Abstract: A method of reducing the impact of a reading deficiency caused by a slow transient response comprises the steps of inserting a light diffuser in a reader's light path to attenuate the high spatial frequency information mediated by the cone receptors of the eye(s) of the reader, and inserting a chromatic filter which limits stimulation to the red and/or green cone receptors relative to stimulation of the blue cone receptors in the eye(s) of the reader whereby the magnitude of the cone mediated sustained response of the reader is reduced towards a more normal balance relative to the impaired transient response of the reader. An apparatus for reducing the impact of a reading deficiency caused by a too slow transient response of a reader comprises a light diffuser and a chromatic filter to limit the red and/or green mediated sustained transmission relative to the blue cone mediated transient transmission, the diffuser and filter being locatable in the reader's light path.

Abstract: A lens (10) that substantially blocks horizontally polarized light and selectively blocks wavelengths between 300 and 549 nanometers. The selective blocking is controlled by a sharp cut-on filter (14) selected to cut-on at either 450, 500, 515, 530, or 550 nanometers. The specific blocking and cut-on point selected is dependent upon the ultimate usage/environment of the lens (10). If a 450 cut-on filter is selected, wavelengths between 300 and 449 nanometers are blocked before a cut-on occurs at 450 nanometers; similarly, a 550 cut-on filter blocks wavelengths between 300 and 549 nanometers before a cut-on occurs at 550 nanometers. The lens (10) also allows 30 to 40 percent of wavelengths over 625 nanometers to be transmitted. The filter (14) in combination with the polarizer (16) blocks harmful Ultraviolet radiation and blue light.

Abstract: A pair of subliminal imaging spectacles is provided with a matched pair of visual subliminal images designed and placed so as to merge into one image due to the stereoscopic effect of human vision and thus to impart a subliminal message to the wearer.

Abstract: A variable density light control apparatus includes plural polarizers, at least two of which are at least partially crossed, and at least one of the polarizers being variable to the extent that it polarizes light as a function of a prescribed input, thereby to control the intensity of light transmitted through the apparatus proportionally to the intensity of the incident light to the apparatus. The range of intensity control can be varied according to the crossed relationship of the polarizers and/or according to the polarization effectiveness of the controllable polarizer. Color effects can be controlled. The apparatus may be utilized in various devices, including displays, windows, eye glasses, and ski goggles.

Abstract: A corrective lens system with selectable optical characteristics includes a lens element for placement in the optical path of a human eye ahead of the retina of the eye and a polarizer element for placement in the optical path of the human eye ahead of the lens element. The polarizer element is configured to pass plane polarized light toward the lens element and the lens element has first and second regions with different optical characteristics, the first region being polarized and arranged to restrict the passage of plane polarized light having other than a given direction of polarization. The lens element may be an intraocular lens, a contact lens, or a corneal implant lens, and one embodiment includes a polarizer element mounted on a spectacles frame as a component of an ocular telescope utilized to treat macular degeneration so that when the spectacles are worn light is restricted from passing through the first region of the lens element.

Abstract: Unique eyewear is disclosed having electronically controlled lens structures in which the optical transmissivity thereof is automatically adjusted to a level correlated with the level of ambient light. The preferred eyewear includes a pair of lens having liquid crystal material therebetween, a control circuit having a sensitivity-adjustable, ambient light sensor, and a power supply. The preferred power supply includes a battery and a photocell array distributed about the periphery of the lens structures. In use, the control circuit senses ambient light level and adjusts the transmissivity of the lens structure to a level correlated with the ambient light level.

Abstract: Variable density sunglasses comprise a frame with a pair of rim portions, each rim portion having sidewalls and first and second interior grooves formed therein between the sidewalls. A pair of first lenses are fixed mounted in the first grooves. A pair of second lenses can be threadably mounted into or demounted from the second grooves along thread planes that are defined by access channels, each access channel extending from a second groove to one of the sidewalls. Each second lens has a circular periphery and a cut extending radially inwardly from the periphery to define two thread edges. The thread edges enable the lenses to be inserted into the respective channels for rotational mounting. Once mounted, rotaation of the second lenses within the second grooves allows the density of light passing through the aligned first and second lenses to be varied.

Abstract: The present invention provides a method of producing a special lens by bonding a polarizing film to an eyeglass lens on the basis of the angle corresponding to the distortion of eyeball, that is, the distorted vision angle measured.

Abstract: A variable density light transmitting device comprising a first light transmitting layer having a plurality of light polarizing areas with differently oriented transmission axes; a second light transmitting layer overlying said first light transmitting layer and movable relative said first layer while remaining generally parallel to said first layer, said second light transmitting layer having a plurality of light polarizing areas of differently oriented transmission axes of corresponding size and arrangement to said light polarizing areas on said first light transmitting layer; said light polarizing areas on said first layer being selectively positionable opposite different ones of said light polarizing areas of said second layer by relative movement of said first layer with respect to said second layer; whereby variable density light transmission is provided through said first and second layers by said relative movement.

Abstract: A lens (10) that substantially blocks horizontally polarized light and selectively blocks wavelengths between 300 and 549 nanometers. The selective blocking is controlled by a sharp cut-on filter (14) selected to cut-on at either 450, 500, 515, 530, or 550 nanometers. The specific blocking and cut-on point selected is dependent upon the ultimate usage/environment of the lens (10). If a 450 cut-on filter is selected, wavelengths between 300 and 449 nanometers are blocked before a cut-on occurs at 450 nanometers; similarly, a 550 cut-on filter blocks wavelengths between 300 and 549 nanometers before a cut-on occurs at 550 nanometers. The lens (10) also allows 30 to 40 percent of wavelengths over 625 nanometers to be transmitted. The filter (14) in combination with the polarizer (16) blocks harmful Ultraviolet radiation and blue light.

Abstract: A sunglass lens has two mounds of ground mineral glass laminated together with a polarization film to form a single lens having inner and outer surfaces. The inner surface is provided with an anti-reflectant coating and the outer surface is provided with a bigradient coating. A process for making the lens is also disclosed in which bigradient material is vaporized in a vacuum coating machine.

Abstract: A method and system are provided for detecting, characterizing and monitoring eye diseases and, particularly, optic nerve diseases, by determining the difference in relative brightness sensed by the two eyes. The method utilizes eyeglasses having a pair of cross-polarizing lenses selectively adjustable for blocking or admitting light into each eye. The patient observes an illuminated test object while looking through the eyeglasses at maximum luminance. By adjusting the relative polarization of the lenses for the eye in which the test object appears the brightest, while occluding the other eye, the amount of brightness sensed by that eye can be compared to the other eye. If there is a disparity in brightness-sense between the eyes within certain pre-established ranges, the nature of the eye disease can be detected and specifically characterized, and its progression or resolution can be monitored.

Abstract: The effect of the glasses of this invention is estimated and is summarized as follows:(1) The effect of reducing the consciousness of eye fatigue is seen.(2) There is a tendency that the mental subjective symptoms are reduced.(3) Because the sense of fatigue is reduced, concentration becomes easier and it is presumed that it is helpful in preventing irritation and weariness.Since fatigue differs depending on the length of working time, it seems to be necessary to take into consideration the effect due to other fatigue than eye fatigue and the effect of motivation. It seems also necessary to investigate under different conditions the latent fatigue which has not been covered in this report.

Abstract: A method and system are provided for detecting and monitoring the treatment of eye disease by determining the presence of visual field defects. The method utilizes eyeglasses having a pair of cross-polarizing lenses selectively adjustable for varying the amount of luminance of an Amsler grid as observed by the patient through the eyeglasses. By adjusting the relative polarization of the lenses separately for each eye until the patient is barely able to see the Amsler grid, the sensitivity of the patient's eyes to the presence of scotomas is greatly increased. By having patients record the presence of scotomas while observing the Amsler grid through the eyeglasses, it is possible to screen patients for visual loss associated with various eye diseases, such as atrophic SMD. Recording the existence of scotomas on a periodic basis enables an ophthalmologist to determine whether atrophic SMD may be advancing to hemorrhagic SMD requiring treatment to prevent permanent loss of central vision.

Abstract: A filter holder which clips on to an ophthalmic trial refraction frame or clip on to a person's spectacles with a clip on attachment is disclosed comprising a knob which rotates a shaft and a gear. The gear engages a ring with teeth in it. This ring is attached to a plate which has a channel cut through it, a pin to locate the position of the variable neutral density filter and a locking disc which holds the filter against the plate. On the back of the filter holder is a disc with an aperture mounted off the axis of symmetry of the filter holder so that the aperture is aligned with the channel in the edge of the plate. The patient sights through the aperture, the channel and the variable neutral density filter. By turning the knob, the neutral density filter rotates and the density in log units can be read on a scale on the front of the body of the filter holder.