FISIKABIO OPTIKA**FISIKA

FISIKA

KEPENTINGAN?Berkaitan asuhan keperawatan orang yang bermasalah pada sistem penglihatannya, khususnya akibat gangguan pada alat optiknya, sepertiAmetropiaAstigmatismeKatarakGlaukoma **FISIKA

FISIKA

TUJUAN PEMBELAJARAN?Memahami & menjelaskan susunan dan fungsi alat optik mata, yang mencakupKorneaKamera okuli anteriorIrisPupil Lensa mataBadan kaca**FISIKA

FISIKA

**FISIKA

FISIKA

**FISIKA

FISIKA

OPTICAL PROPERTIES OF THE HUMAN EYE.The human eye as a visual analyzer makes it possible to distinguish rather accurately between colors, form, dimensions, degree of illumination, and the location of objects in the immediate environment (Figure A2-1). **FISIKA

FISIKA

OPTICAL PROPERTIES OF THE HUMAN EYE.The forward portion of the eye, which is turned toward the light, contains a light-refracting apparatus which transmits the image to a light-sensitive membrane -- the retina; this apparatus consists of a system of refracting media and surfaces -- the cornea, the crystalline lens, the aqueous humor, and the vitreous humor filling the optical cavity.(The light-refracting apparatus also includes the ciliar humor and the iris, which has an opening, the pupil, in the center of it.) **FISIKA

FISIKA

**FISIKA

FISIKA

1. Cornea (transparent, grasslike portion of coat of eyeball).2. Conjunctiva (mucous membrane which lines eyelids and is reflected onto eyeball).3. Ciliary muscle (smooth muscles, controlling alteration of crystalline lens).4. Muscle of eyeball.5. Space posterior to crystalline lens.6. Sclera (toughest of the three membranes, forming the outer protective and supporting layer of the eye ball).7. Choroid (vascular coat of the eye). 8. Retina (innermost tunic of the eye, containing receptors, rods and cones).9. Optic disk (blind spot of retina).10. Optic nerve (transfers images from retina to visual nerve centers located in the brain). **FISIKA

FISIKA

11. Anterior chamber (filled with aqueous humor).12. Iris (opening in center is called the pupil, contains groups of smooth muscles that dilate and contract pupil).13. Posterior chamber (filled with aqueous humor).14. Suspensory ligaments (zonule of Zinn).15. Crystalline lens (transparent biconvex body enclosed in transparent sheath, suspended from ciliary body by suspensory ligaments).16. Vitreous (transparent jelly-like substance contained within transparent membrane close to retina).17. Fovea central is (a pit in the middle of the macula lutea).18. Macula Lutea (point of clearest vision, contains greatest number of cones). **FISIKA

FISIKA

**FISIKA

FISIKA

Figure A2-2. Phenomenon of Spherical Aberration**FISIKA

FISIKA

Figure A2-3. Phenomenon of Diffraction of Light on the Pupil**FISIKA

FISIKA

Figures A2-4. Schemes Showing the Refraction Rays in the Eyes: {a) Normal, (b) Nearsighted (c) Farsighted.**FISIKA

FISIKA

Figure A2-5. Scheme showing the Refraction of Rays in an Astigmatic Eye.**FISIKA

FISIKA

Figure A2-6. Chart for Discovering Astigmatism.**FISIKA

FISIKA

Figure A2-7. Determining which eye is dominant.**FISIKA

FISIKA

Figure A2-8. Muscles of the Right Eye. Arrows Show the Direction in which the Eyeball turns when the Muscles designated**FISIKA

FISIKA

SNELLEN CHARTA Snellen chart is an eye chart used by eye care professionals and others to measure visual acuity. Snellen charts are named after the Dutch ophthalmologist Herman Snellen who developed the chart in 1862.[1] Vision scientists now use a variation of this chart, designed by Ian Bailey and Jan Lovie.

**FISIKA

FISIKA

DESCRIPTIONThe traditional Snellen chart is printed with eleven lines of block letters. The first line consists of one very large letter, which may be one of several letters, for example E, H, or N. Subsequent rows have increasing numbers of letters that decrease in size. A person taking the test covers one eye, and reads aloud the letters of each row, beginning at the top.The smallest row that can be read accurately indicates the visual acuity in that eye.

**FISIKA

FISIKA

Typical Snellen chart to estimate visual acuity**FISIKA

FISIKA

PERTANYAAN?Sebutkan bagian mata yang berfungsi sebagai alat optik!Apakah fungsi mata sebagai alat optik?Bagian manakah dari alat optik mata yang dapat berubah kekuatannya untuk membiaskan sinar?Apakah yang dimaksud dengan ketajaman penglihatan?Bagaimana cara memeriksa ketajaman penglihatan?Bagaimana rumus untuk menentukan ketajaman penglihatan?Apa yang disebut kartu Snellen?Ada berapa deret huruf pada kartu Snellen?Apa yang disebut emetropia dan ametropia?Kemukakan ada berapa macam ametropia!**FISIKA

FISIKA