 vividha takala kalla gurinchina yea paeraani batti ,  kanti rakaalu elaa vargeekarinchabaddaayi mariyu yenduku ?
 padi vaervaeru kanti leout ‌ lu unnayi - vaasthavaaniki manaollu saadharanamga upayoegimchae optically emage ‌ ni sangrahinche prathi saankethika paddathi ,  joom mariyu fresnell lens ‌ lu minahaa prakruthilo jaruguthai .  kanti rakalanu ooka putakara photoriseptive uparitalamtho  " saralamaina kallu "  mariyu  " sammeelhanam kallu " gaaa vargeekarinchavachhu ,  ivi kumbhakara uparithalampai veyabadina anek vyaktigata lens ‌ lanu kaligi untai . " simply "  anede sanklishtata ledha teekshanhata yokka taggina stayini suuchimchadani gamanimchamdi .  nijame ,  edaina kanti rakam dadapu edaina pravartana ledha paryaavaranaaniki anugunamga umtumdi .  kanti rakalaku pratyekamaina parimithulu reselution Bara - sammeelhanam kalla yokka bhautikasastram vatini  1°  kante merugaina reselution ‌ nu saadhinchakundaa nirodhistundi .  alaage ,  suupar ‌ position kallu opposition kalla kante ekuva sunnitatvaanni saadhinchagalavu ,  kabaadi avi chikatiga umdae jeevulaku bagaa saripotayi .  photoreceptor yokka selular nirmaanam aadhaaramga kallu kudaa remdu samuhaluga ostayi ,  photoreceptor kanaalu siliate  ( sakasherukaalalo vale )  ledha rabdomeric .  yea remdu samuuhaalu monophylatic kadhu ; cnidaria  kudaa silliatead kanaalanu kaligi umtumdi mariyu konni gastropod ‌ lu ,  alaage konni annelid ‌ lu rendintini kaligi untai .

 konni jeevulu photosensitive kanaalanu kaligi untai ,  avi parisaraalu kaantivantamgaa vunnya ledha chikatiga unnaayo ledo gurtimchadam minahaa aemee cheyalevu ,  idi sarkadian rhythm ‌ l pravaesaaniki saripottundi .  ivi kallugaa pariganinchabadavu endhukante avi ooka avayavamgaa pariganinchabadenta nirmaanaanni kaligi undavu mariyu ooka chitranni utpatthi chaeyavu .
 kallu  " sadarana kallu "  mariyu  " sammeelhanam kallu "  ani remdu rakaluga vargeekarinchabaddaayi .  yea sandarbhamlo , " sadarana kallu "  antey avi sanklishtata ledha teekshanhatanu tagginchaayani kadhu ,  conei avi ooka putakara photoriseptive uparitalam kaligi untai .  idi ooka kumbhakara uparithalampai anek vyaktigata katakamulanu kaligi umdae  " sammelhana kallu " ki viruddhamgaa umtumdi .  mro maatalo cheppalantey ,  vaati photoreceptor yokka selular nirmaanam aadhaaramga kallu remdu samuhaluga ostayi ,  avi siliate  ( sakasherukaalalo vale )  ledha rabdomeric .