Psikologi faal Indera penglihatan 1 & 2

1. Matrissya Hermita Psikologi faalIndera penglihatan 1 & 2

2. RESEPTOR dan PENGINDERAAN Reseptor : struktur yang menerima stimulus/rangsangan. Terbagi atas : Eksteroreseptor Reseptor yang menerima rangsang/impuls dari luar tubuh. Umum/biasa : suhu, tekanan. Khusus : reseptor indera pengelihatan : retina penghidu : bulbus olfactorius pengecap : gema gustatoria Pendengaran : cocchlea Taktil : paccini, meissner

3. Interoseptor Reseptor yang menerima rangsang/impuls yang berkaitan/berasal dari organ dalam tubuh eg. Lapar, haus, rasa sakit dalam Propioseptor Reseptor menerima rangsang/impuls berkaitan dengan bagian anggota gerakan tubuh eg. Posisi dan pergerakan tubuh

4. INDERA PENGLIHATAN Anatomi MATA Terdiri atas bulbus occuli (bola mata), struktur pelindung : cavum orbita (rongga mata), palpebrea (kelopak mata), conjunctiva, glandula lacrimalis (kelenjar air mata), dan penggerak bola mata (otot ekstrinsik penggerak bola mata : 4 mm. rectus, 2 mm. Obliquus) → melekat jadi 1 dsb capsula tenon. BOLA MATA Bola mata mempunyai bentuk hampir “bulat” (D ± 23mm), dengan bagian anterior yang lebih cembung,disebut cornea. Pada kutub posterior, N II keluar menuju otak pada bagian medial dari axis bola mata, dimana fovea centralis yang merupakan titik tempat bayangan jatuh berada lebih lateral.

5. Dindingnya terdiri atas 3 lapisan Lapisan terluar (tunica fibrosa) → sclera & cornea Lapisan tengah (tunica vasculosa) → choroid, corpus cilliaris, iris Lapisan terdalam (tunica interna) → retina, sel epithel pigmen retina Terbagi menjadi 2 ruangan yaitu COA (camera occuli anterior) dan COP (posterior) oleh iris. Media refrakta → cornea, aquos humor, lensa, corpus vitreum Apparatus akomodasi → lensa, zonula, otot cilliaris

6. Sclera The sclera, which is white in adults, consists ofpacked lamellae of collagen fibers covering theposterior 5/6 of the eye. At the corneal limbus it becomes the substantia propria corneae (stroma). Cornea The cornea has a diameter of about 12 mm inadults. The outside of the cornea consists of stratified nonkeratinized squamous epithelium, which changes to the epithelium of thebulbar conjunctiva at the corneal limbus. Theinside is formed by a single layer of flat endothelialcells. The refractive power of thecornea is about 42 diopters (Db). The centralthickness is approximately 500 μm. Lens The lens, with a horizontal diameter of about10 mm, is situated in the posterior chamber ofthe eye. It is about 3–4 mm thick at the center. It is a biconvex lens, with the anterior surfaceless curved than the posterior surface. The lensshell, which surrounds the nucleus concentrically,lies beneath the lens capsule.

7. Vitreous Body The vitreous body, which is 95 % water, fills thevitreous space situated behind the lens. Its gelatinousconsistency is due to the presence ofhyaluronic acid, mucopolysaccharides, and collagen fibrils. Choroid The choroid occupies the major part of the middlelayer of the eye. In addition to arteries andveins, it also carriesapproximately 15–20 ciliarynerves. It is separated from the retina byBruch’s membrane, which is 2 μm thick. Iris and Pupil The iris, like a diaphragm, forms the pupil. The iris isthinnest at themargin of the pupil and allowsthe bilaminar pigmented epithelium on theback to be seen. The pupil is surrounded by the sphincter pupillae muscle (parasympathetic innervation via the oculomotor nerve), the innervationof which produces contraction of thepupil (miosis). At the margin of the pupil, theiris is widely connected with the ciliary body.The muscle fibers of the dilatatorpupillae muscle(cervical sympathetic) run here, contractionof which leads to pupil dilatation (mydriasis).

8. Retina The retina forms the inner layer of the eye. Divided into a nonsensory (anterior) part and an opticpart. The macula lutea(yellow spot) is lateral to this with the foveacentralisat its center, the site of maximum visualacuity. The inner retina includesthe photoreceptor cells and nine furtheridentifiable layers of the cerebral layer. Primary sensory epithelial cells→120 million rods and 6–7 million cones. There are only cones in thefovea centralis, with no other layers of the cerebrallayer. Rods and cones constitute the retina’s receptors. fovea centralis consists exclusivelyof cones, which are responsible for colorvision in good lighting (photopic vision). The rods are responsible for vision in poorlight (scotopic vision); their greatest density isaround the fovea centralis but they are also distributedoverthe entire retina. The photoreceptorsare absent in the region of the optic disc → blind spot

9. Optic Nerve and Optic Tract The optic nerve is about 45 mm in length, twothirdsof which is inside the orbit. At the laminacribrosa 1 million nerve fibers leave theeyeball and from this point are surrounded bya medullary sheath of oligodenroglia, duramater and pia mater. After passing through theoptic canal, it reaches the optic chiasm on thefloor of the third ventricle after running about10 mm in the middle cranial fossa. Here thenasal fibers of the retina cross to the oppositeside. The optic nerve fibers run as the optictract as far as the lateral geniculate body. The optic radiation (Gratiolet’s radiating fibers) runs from here through the posterior crus ofthe internal capsule to the primary optic visualcortex, the area striata, area 17.

10. Accommodation Accommodation signifies the ability of the eyeto focus the rays from objects to form a clearimage on the retinal plane in relation to the objects’distance from the eye. Accommodation isbased in particular on the ability of the elasticlens to change from a more spherical shapewith highconverging power (near focus) to amore elliptical shape with low converging power (distant focus). Visual acuity means the resolvingability of the eye with an optimally correctinglens, i.e. the ability of the retina barelyto distinguish two points from one another(resolution threshold). A normal eye can justdifferentiate two points when the rays emergingfrom them form an angle at the eye of oneminute of arc (1/60 degree). Visual acuity is calculatedfrom the actual distance of the pointsfrom the eye divided by the distance at whichthe normal eye can resolve the points, and inthe normal eye it is therefore 1ßq = 1.0. Optotypes projected into the distance

11. Visus sangat dipengaruhi oleh sifat fisis mata (aberasi mata = kegagalan memfokuskan bayangan tepat di fovea centralis), besarnya pupil, komposisi cahaya, kemampuan akomodasi, elastisitas otot, intensitas cahaya, faktor retina V = d/D

12. Adaptation Adaptation (A) signifies the adjustment of theeye to different light levels. This is a complexprocess, which comprises a change in pupilsize, a change between rod and cone vision, anda change in the sensitivity of the retina. Accordingto the duplicity theory of vision, daytimeand color vision (photopic vision) is afunction of the cone apparatus, while vision indim light and night vision (scotopic vision) areprovided by the rod apparatus. Light adaptationmeans the transition to photopic visionand is based on pupil constriction and the transitionfrom rod to cone vision with the breakdown of rhodopsin.

13. GERAK BOLA MATA N III → m rectus superior, m.rectus inferior, m. rectus medial, m.obliquus inferior N IV → m obliquus superior N VI → m. rectus lateral

14. BUTA WARNA AKROMATISME/AKROMATOPSIA/Total → tidak dapat membedakan warna dasar, terlihat hitam dan abu-abu DIAKROMATISME/Partial → bisa mbedakan warna tertentu Deutrinophia : sel kerucut hijau (-) Protanophia : sel kerucut merah (-) Tritanophia : sel kerucut biru/kuning (-) Menurut Hering ada 3 macam fotokhemis yang mempunyai 6 macam kualitas yang memberikan 6 macam sensasi → substansi putih-hitam, merah-hijau, biru-kuning. Test Buta warna → Uji Holmgren, Uji Stiling-Isihara.

15. Mata manusia dapat mendeteksi hampir semua gradasi warna bila cahaya monokromatik merah, hijau dan biru dicampur secara tepat dalam berbagai kombinasi tergantung persentase campuran warna-warna dasar tersebut. Young & Helmholtz → Sel kerucut dapat menerima warna merah, hijau dan biru. Ke tiga macam sel kerucut mengandung fotokhemis yang dapat diurai oleh sinar matahari, bila ketiga macam sel kerucut itu mendapat stimulus yang bersamaan maka akan terlihat warna putih. Warna-warna lain merupakan kombinasi dari ketiga macam warna dasar.

16. Thank You!!!!!