Ophthalmology of eye examination presentation

Examination of eye and various instruments used for eye evaluation

1. OPHTHALMOLOGY Dr. ARCHANA KUMARI Assistant Professor VSR 421 (2+1) Department of Surgery And Radiology Bihar Veterinary College, BASU, Patna-800014

2. Aesthesiology – Deals with description of special sense organs of touch , smell, sight and hearing . Ophthalmology – Is the science which deals the structure function and disease of the eye. Optometry –Optometry is a health care which involves examination of the eye and applicable visual system for defect or abnormal as well as the medical diagnosis and management of eye disease. Orthoptics -Treatment of defectives visual habits, defects of binocular vision (such as strabismus) by non-surgical measure specially by exercise to strengthen the muscle.

3. Anatomy of Eye

4. Eye lid :- Upper lid is much more extensive and more movable than the lower one. Palpebral fissure :- The interval between the lids is termed the palpebral fissure. When eye is closed, it is an oblique. When open it is biconvex in outline. The ends of the fissurs are the angles or canthi and are distinguished as medial and lateral (Rounded). The lids unite on either side and form the commissures .

5. Anatomy of eye

6. Refractive media of the eye – Cornea, aquons humour, lens and vitrous humour Refractive surface of the eye – Anterior surface of the cornea, anterior surface of the lens and post-surface of lens.

7. Rectangular Pupils like those in goats , cow and horses allow for a wider field of vision.

8. Panctum lacrimal :- The edges of each lid is pierced near the medial angle by a minute slit like opening the punctum lacrimale which is the entrance to the lacrimal duct. The lacrimal duct upper and lower begin at the puncta and converge at the medial commissure to open in to the lacrimal sac. Harders gland ( Harderian gland) :- Resembles lacrimal gland situated on the inner surface of the 3 rd eyelid close to its outer border. Tarsal gland :- Modified sebaceous gland situated within the tarsal plate. The duct of these gland open along the free border of the eyelid.

9. . Tunic of eye Sclera Tunic fibrosa Cornea Choroid Vascular tunic or Uvea Ciliarybody Iris Nervous Retina

10. Muscles of E ye [ 7 ] Muscles Inervation Action Dorsal rectus Oculomotor III Elevate globe Ventral rectus Oculomotor Depresses globe Medial rectus Oculomotor Turns globemedially ( hasll ) Lateral rectus Abducent IV Turns globe Dorsal Oblique Trochlear IV Rotate (12-0 clock) Ventral oblique Oculomotor III Rotate (12-0 clock) Retractor occului Abducent VI Retracts globe 4 straight 2 Oblique 1 Retactor

11. Muscles of the Eye

12. EXAMINATION OF THE EYE

13. Naked eye examination – A gross abnormalities of the anterior segment of the eye can be detected by naked eye examination. Penlight examination in dark room - Penlight examination. The light should be used from as many different angles as possible. Handling the patient as part of the eye examination.

14. Opthalmoscope (Better necessary to dilate the pupil (atropine 2% into eye about fifteen minutes before examination). Mydriatics – Dialate the pupil Atropin sulphate, coccin HCl Distant direct ophtholmoscopy Distant direct ophthalmoscop y

15. Close direct ophthalmoscopy – Close direct ophthalmoscopy (a) placingthe ophthalmoscope (b) Viewing theeye . Note that the fingers holding the ophthalmoscope areresting against the patient’s headandthat excessiverestraint is unnecessary, unlessthe patientis dangerous if unrestrained. Close direct ophthalmoscopy the head is being restrained correctly, with the hand under the mandible. The eye that is closer to the dog is being used for the ophthalmoscopy . The ophthalmoscope must be close to both the clinician’s eye and the patient’s eye.

16. Indirect Ophtholmoscopy Monoocular (2) Binocular Monocular indirect ophthalmoscopy . Note that the fingers holding the lens are in contact with the patient’s head. Binocular indirect ophthalmoscopy . This gives a wide-angle view of the fundus with stereopsis .

17. Ultrasonography – Helps in the diagnosis of luxation of lens and retinal detachement . Electroretinography (ERG) – To asses the condition of retina when ophthalmoscope examination is not possible as in cataract also help in prognosis in glaucoma .

18. Tonometer ( sehietz tonometer ) Dog Iop – 15 to 25 mm . Estimation of intraocular pressure (IOP) using a rebound tonometer (“ Tonovet ”). The probe-tip is gently allowed to contact the axial corneal surface (without the use of local anesthetic ) by pressing the measurement button. Several readings are taken, so that aberrant readings may be disregarded. prevent “pooling” of residual stain.

19. The ball is held high and the animal's attention directed towards it by making a noise. The ball is then released in the animal's field of view and the animal is obse r ved to see whether it follows its path . The normal response is movement of the eye to track the falling cotton ball. Cotton Ball test

20. It standardized strips of filter paper measure equeous production over one minute in an unanaesthetized eye. Normal value for the Shirmer test in the dog are a mean 20 mm and a minimum of 15 mm. 10-15 mm is border line. Measurement of lacrimal function using gradated (“ Schirmer ”) tear strips. The tip of each strip is folded and placed into the lower medial fornix for one minute and the resultant STT1 value recorded. This test should be performed before the installation of any topical agents. prevent “pooling” of residual stain. Shirmer test

21. Ulceration of cornea Nasolacrimal patency. The strip should be wetted with sterile saline or water and touched to the dorsal or ventral bulbar conjunctiva. A lternatively , one drop of fluorescein solution can be applied to the eye. The eye is then irrigated with further saline to flush excess fluorescein from the ocular surface. Fluoresein test

22. A positive Jones or fluorescein passage test result, as evidenced by the appearance of fluorescein stain at the nostril following its application to the ipsilateral corneal surface. In some dogs the nasolacrimal duct opens caudally within the nasopharynx , and fluorescein stain is found in the mouth rather than the nostril after application of the stain to either corneal surface. Fluoresein test

23. Leave the animal for walking towards an obstacle and observing whether he tries to avoid it or walk into it. Ask the owner to stand at the end of this “ Maze” , whereas the dog at the other end. Ask the owner to prompthe dog to come towards him / her. Examine how the dog navigate the maze. Animal is said to fall the test the test , if it collides with Obstacle. Do the 'Maze 'test both in ' low light ' as well as 'bright light ' conditions. To asses animal's 'Scotopic' as well as 'Photopic' vision 'Maze' Test or Obstacle Test

24. Maze test or Obstacle test

25. Elicited by making direct and sudden hand motion across the visual field of the ipsilateral eye while the contralateral eye is covered. The normal/positive response is blink. Perform this test in ambient light conditions. Keep the movement of the hand gentle ( since blind animal will respond to this air current by blinking , A false positive result ). Perform this test from different aspects of the eye. As this is a learned cortical response, it is absent in very young patients normally. (Untill 12 weeks in dogs ) 'Menace Response' Test

26. Interpretation of Menace test Positive -Animal is visual and eyelid are functional Negative - Animal is blind or Lesion in facial nerve or Physical hindrance in closure of eyelids Incomplete eyelid closure ( Lagophthalmos ) is common in beachycephalic breeds of dogs and cats.

27. This is tested by lightly touching the lateral and medial canthi one by one. The normal response is blink. 'Palpebral /Blink Reflex' Test Afferent pathway- Opthalmic branch of Trigeminal Efferent pathway- Facial Nerve Muscle - Orbicularis oculi.

28. This is tested by lightly touching the peripheral cornea with the sterile swab tip or wisp of cotton wool. The normal respnse is ' blink '. 'Corneal Reflex' Test Afferent Pathway - Opthalmic branch of trigeminal Efferent pathway - Facial nerve (Eye lid closure) Abducens (Globe retraction) Muscles - Orbicularis oculi (eye lid closure) Retractor Oculi (Globe retraction)

29. This is tested by showing bright focal light quickly into the eyes, one at a time.- The normal response is blink The blink is mostly ipsilateral and to lesser extent contralateral. 'Dazzle Reflex' Test This is a subcortical Reflex It is merely reflective of the functionality of the- Retina optic nerve supra optic nuclei of hypothalamus But not the Visual Cortex

30. For this test, the Pupil is exposed to bright light in a semi dark room. A normal reflex will be the contraction of pupil. Record both direct and indirect PLRs Direct PLR :- When the movement of ipsilateral iris is noted. Indirect / Crossed PLR :- It is the contraction of the contralateral pupil while light is being shown in other eye. Pupillary Light Reflex (PLR) Test Afferent Pathway: - Optic Nerves Efferent Pathway: - Oculomotor :It is parasympathetic fibers Muscles :- Iris Sphincter

31. Thank You