<p> Ophthalmic Surgery Lab</p><p>Anatomy of the Eye</p><p>Conjunctiva – coverlet like thin transparent membrane that lies over the cornea extending onto the inner lids both upper and lower</p><p>Three Layers called “Tunics”</p><p>1. Fibrous tunic</p><p>Cornea = anterior 1/3rd of eye</p><p>Sclera = posterior 2/3rd of eye</p><p>On the outer surface of the sclera are the 6 extrinsic (outside) muscles also called EOM (extra- ocular muscles) which are what control globe/eye movement:</p><p>Superior oblique (SO), inferior oblique (IO), lateral rectus (LR), medial rectus (MR), inferior rectus (IR), superior rectus (SR)</p><p>EOM are controlled by three of the twelve total cranial nerves:</p><p>LR6 (SO4) 3</p><p>The lateral rectus (LR) is controlled by the VI cranial nerve called the abduscens</p><p>The superior oblique (SO) is controlled by the IV cranial nerve called the trochlear </p><p>All other EOM are controlled by the third cranial nerve called the occulomotor </p><p>Cranial Nerve Review from class:</p><p>I. Olfactory –smell (think of the old paper factory in Canton that stinks!)</p><p>II. Optic – vision</p><p>III. Occulomotor</p><p>IV. Trochlear</p><p>V. Abduscens </p><p>2. Vascular Tunic</p><p>Contains two intrinsic (inside) muscles:</p><p>Iris – because it is a circular muscle composed of smooth muscle, it can be controlled by medications that allow it to dilate the pupil or contract the pupil Ophthalmic Surgery Lab</p><p>Ciliary muscle – controlled the shape of the lens which is what allows you to achieve the function of “accommodation” which is simply put to “focus”</p><p>3. Nervous tunic</p><p>Retina</p><p>Two Cavities in Eye</p><p>1. Anterior Cavity </p><p>Contains aqueous humor – body continues to reproduce and normally your body maintains this through drainage into the Canal of Schlemm (where cornea meets sclera inside the fibrous tunic) so that you do not overproduce it which can lead to increased intra-ocular pressure)</p><p>Contains two chambers:</p><p>Anterior chamber = front of cornea to iris</p><p>Posterior chamber= iris to lens</p><p>Cavities separated by normally intact lining/capsule behind/surrounding the lens</p><p>2. Posterior Cavity also called Vitreous chamber</p><p>Contains retina and vitreous humor (vitreous body)</p><p>Vitreous humor –what you have at birth is all you will ever have</p><p>Provides shape to the globe and keeps retina in place</p><p>Ophthalmic Medication Classifications</p><p>Majority are in a liquid/eye drop (gtt) form. Some are in ointment (ung) form. Ophthalmic Surgery Lab</p><p>1. Topical antibiotics</p><p>2. Dyes</p><p>3. Topical anesthetics</p><p>4. Anti-inflammatories</p><p>5. Mydriatics – dilate iris hence the pupil to allow visibility into the eye</p><p>6. Miotics – constrict the iris making pupil smaller used to maintain a new lens in place post- phacoemulsification or extracapsular lens extraction</p><p>7. Viscoelastic agents </p><p>8. Irrigants</p><p>Examples of frequently used ophthalmic medications:</p><p>1. Topical antibiotics - neosporin, erythromycin, gentamycin, neomycin, tobramycin</p><p>Often combined with anti-inflammatories</p><p>2. Dyes – rose Bengal, fluorescein</p><p>3. Topical anesthetics –cocaine, lidocaine, tetracaine, bupivacaine, proparacaine</p><p>4. Anti-inflammatories – dexamethasone, prednisolone (Pred-forte)</p><p>Often combined with antibiotics</p><p>5. Mydriatics – atropine sulfate</p><p>6. Miotics – Pilocarpine</p><p>7. Viscoelastic agents –Healon, Amvisc</p><p>8. Irrigant – BSS (balanced salt solution)</p><p>Common Eye Pathologies</p><p>Chalazion – benign tumor that is the result of an inflamed swollen oil gland on the eye lid</p><p>Corrective surgery called chalazion excision</p><p>Pterygium – overgrowth of conjunctiva from inner canthus of eye that can extend into the iris Ophthalmic Surgery Lab</p><p>Corrective surgery called pterygium excision</p><p>Cataracts – opacity or clouding of the lens</p><p>Corrective surgery called phacoemulcification (soft lens seen in younger patients) or extracapsular lens excision (hard lens seen in older patients)</p><p>Strabismus – misalignment of the eye(s) due to EOM tone issues</p><p>Corrective surgery called Recession Resection (R & R). Patient may only need one or the other or both.</p><p>Surgical Considerations:</p><p>Careful steady movements when working around MD and microscope; don’t bump either!</p><p>Use BSS to keep cornea moist intra-operatively (slow drops periodically out of MD line of sight)</p><p>Lint-free towels or drapes</p><p>No sponges! </p><p>Use Weck Cells (spears)</p><p>Preservative-free ophthalmic medications</p><p>Never use water in the eye</p><p>Powder-free gloves</p><p>Careful slow transport if moving to a stretcher or bed post-operatively</p><p>Patients are awake so watch your conversations in that they are not inappropriate or loud</p>