Fundamentals

Lipophilic

( lipid loving ) corneal epithelium

Ocular changes observed in Axenfeld Rieger syndrome

(a) Corectopia on the right eye (displaced pupil is shown by an arrow); (b) Polycoria (the extra hole on the iris is shown by an arrow); (c) Posterior embryotoxon, the prominent Schwalbe's line is indicated with arrows; (d) Iris strands bridging the chamber angle as seen on gonioscopy.

Hydrophilic

(water-loving) corneal stroma polar compounds will have an easier time traversing it

Phototransduction

1) A photon of light strikes the !1 cis retinal molecule causing it to isomerize into all trans retinal 2)This isomerization causes activation of covalently attached OPSIN molecule which then activates multiple G-protein mediated signaling pathways 3) These signaling pathways eventually lead to closing of ion channels that prevent the influx of Na++ and Ca++ 4) Thus the photoreceptor outer segment membrane becomes hyperpolarized

How many short posterior ciliary nerve

10 short and 20 short posterior ciliary arteries tht enter the globe around the ON. 2 long posterior ciliary nerves 2 long ciliary arteries enter the globe in either side of the optic nerve on the horizontal meridian

Adult corneal dimensions

12mm horizontal and 11 vertical

Aqueous production

2 to 3 uL/min

Effects of PILO

23 year-old with pano manifest refraction Hate pilo will become more myopic and thus symptomatic especially for distance viewing . Young hyperopic with +2.00 D would actually be closer to plano with PILO. the 72 year old with +1.00 and with cyclo has little reserve accommodative will not have a refractive change.

Direct acting muscarinic

3 min actions Miosis , accommodation and increased aqueous outflow Accommodation causes the lens to acquire a more spherical shape thus adding refractive power to the overall refractive state of the eye .Accommodation occurs through the contraction of the circular muscle constriction . The longitudinal muscle of thee ciliary body attaches to the scleral spur .Contracture causes tension on the scleral spur which opens the TM PILo causes that .

First tear

3-6 weeks

annulus of Zinn

3N#is 6. V1, sympathetic roots of the CG

Pathway for conjugate horizontal gaze

A combination of voluntary and involuntary eye movements allows us to find, fixate on, and track visible objects in space. Conjugate voluntary eye movements are initiated in the frontal eye field, which lies anterior to the motor cortex in Brodmann's area 8 along the middle frontal gyrus. Frontal eye field fibers traverse the posterior limb of the internal capsule and the cerebral peduncle to terminate in the contralateral paramedian pontine reticular formation (PPRF), also known as the horizontal gaze center. PPRF neurons send axons in turn to the ipsi-lateral abducens nucleus and the contralateral oculomotor nucleus, the latter via the medial longitudinal fasciculus (MLF). The synchronous discharge that is produced in the ipsilateral lateral rectus and the contralateral medial rectus muscles results in voluntary conjugate horizontal gaze Activation of the left frontal eye fields results in conjugate horizontal gaze to the right. When rapid and precise, these voluntary conjugate eye movements are called saccades. Saccades permit the eyes to repeatedly sample the horizontal visual world to find and fixate on an object. A less characterized horizontal gaze center is located in the occipital lobe. This center permits voluntary smooth pursuit movements following objects moving in space.

ophthalmic artery with various branches

A diagrammatic representation of anastomoses of the ophthalmic artery with various branches of the external carotid artery

OA ophthalmic artery,

A diagrammatic representation of the origin and intracranial and intracanalicular course of the ophthalmic artery and its subdivisions, as seen on opening the optic canal ICA internal carotid artery, OA ophthalmic artery, OC optic canal, ON optic nerve, P periosteum, PPS point of penetration of the dural sheath

TM structures

A schematic illustration of the architecture of the conventional outflow pathway in mouse eyes, showing the relationship between the CM, TM, and inner wall (IW) of SC. The CM bifurcates into internal and external branches. An EL fiber net is present within the TM and juxtacanalicular tissue, and tendons of the external CM and the EL fibers of the choroid bend to insert into the juxtacanalicular EL net or connect directly to the IW endothelium. The internal CM makes connections to the lamellated TM that is continuous with the CB stroma. Elastic fibers bridge between the lamellated TM and juxtacanalicular tissue, and αSMA-labeled cells (pink) are present within the lamellated TM and occasionally in the juxtacanalicular tissue.

Primary route of ATP production ot the lens

Anaerobic glycolysis

Lens metabolism

Anaerobic glycolysis 78% of the glucose is metabolized through this pathway Aerobic

PAX6

Aniridia , posterior embryotoxon , Peters Anomaly , Axenfeld anomaly , and congenital cataracts .

Gland of Moll

Apocrine sweat gland

Uveal scleral outflow

Aqueous flows across the CB and into the SUPRACILIARY SPACE.It is pressure independent AC to ciliary muscle , then into the supraciliary and suprachoroidal spaces .This fluid then exits the ye either through intact sclera or along the vessels that penetrate it

Mydriatics and Cycloplegics from longest to shortest

Atropine 7-14 days Scopolamine 4-7 Homatropine 3 days Cyclopentolate 2 days Tropicamide 4-6 hours Phenylephrine 3 to 5 hours

Axenfeld's nerve loop

Axenfeld is an extension of the posterior ciliary nerve, which makes a loop (arrow 3) through the sclera (arrow 5) in the region of the anterior ciliary arteries or between the rectus muscle insertions. In the figure below the nerve is posterior to the junction of the ciliary muscle at the pars plana. The ciliary epithelium is evident (arrow 1) and so are the lens zonular fibers (arrow 2) as they sweep back along the pars plana. The nerve loop is smooth and dome shaped measuring 1-2 mm in size. The loop may appear cystic and or pigmented leading to a surgical misadventure. The loops are present in about 12% of human eyes. Virtually all are associated with blood vessels and all are pigmented. The loop may protrude to cause symptoms but most importantly, Axenfeld's nerve loop is in the differential of a fixed pigmented epibulbar lesion. It is frequently misdiagnosed as a nevus or melanoma. Manipulation of the lesion elicits pain from the subject as the nerve is present at the external surface (arrow 4). This is the sign that should make one reconsider biopsy! Infrequently, the nerve loops may be multiple in the same eye (0.5%) or bilateral (1%) .

Whih visible light is particularly harmful to the retina

BLUE LIGHT leads to the formation of the phototoxic compound A2E which damages the cytochrome oxidase and leads to RPE death and subsequent photoreceptor death .

Dorsal artery

Becomes the OA at around the six week of gestation Supplies the short posterior ciliary arteries , CRA, and the temporal long posterior ciliary artery.

Mechanism of action of lidocaine

Blockage of axonal sodium channels The protonated form blocks on the inner wall of the axonal cell membrane

PGA side effect in ruptured capsule

CME with Latanoprost

NFL

CRA

Peters anomaly

Central cloudy cornea is a rare congenital form of anterior segment dysgenesis in which abnormal cleavage of the anterior chamber occurs. It is characterized by a central corneal opacity (leukoma) due to defects in the posterior stroma, Descemet membrane, and endothelium. Peters' anomaly is one disease in a constellation of diseases that causes corneal opacity due to anterior segment dysgenesis (ASD) during development. It has been known over the years as primary mesodermal dysgenesis of the cornea, congenital anterior synechiae, posterior keratoconus and anterior chamber cleavage syndrome1. Peters' anomaly affects the iris, corneal endothelium and Descemet's membrane leading to Peters' type I. Peters' type II in addition will have lens abnormalities and tend to be bilateral. 60% of those with Peters' anomaly are bilateral. In both forms, opacification of the cornea leads to an amblyogenic effect on a developing infant. Peters' plus syndrome includes short disproportionate stature, developmental delay, dysmorphic facial features, cardiac, genito-urinary, and central nervous system malformation. These systemic findings are seen in up to 60% of patients. Peters' is also associated with many other ocular pathologies including glaucoma, sclerocornea, corectopia, iris hypoplasia, cataract, ICE syndrome, aniridia, iris coloboma, persistent fetal vasculature and microcornea. Premature infants are at highest risk for development of ACD including Peters' anomaly. In addition, a deficiency of heparan sulfate can lead to abnormal neural crest development in utero. Fetal alcohol syndrome has been reported as a cause of Peters'. Peters' anomaly is diagnosis by anterior segment exam in infants found to have corneal opacification present at birth. B-scan ultrasound or ultrasound biomicroscopy can be used to examine the anatomic relationship between the lens, iris and cornea. Genetic testing of one of the aforementioned genes can help to confirm Peter's anomaly, but is classically diagnosis clinically.

The picture above exhibits a CRAO with sparing of the foveal retina due to the presence of a cilioretinal artery

Central retinal artery occlusion (CRAO) occurs when occlusion of the central retinal artery, a branch of the ophthalmic artery, results in infarction of the inner retina with subsequent, typically severe, vision loss. The picture above exhibits a CRAO with sparing of the foveal retina due to the presence of a cilioretinal artery. A cilioretinal artery has been found to be present in 49.5% of patients. The cilioretinal artery branches off the ophthalmic artery and supplies the inner retina in these individuals. This is in contradistinction to the posterior ciliary arteries, which branch off the ophthalmic artery and supply the choroid and outer retina. Patients with a cilioretinal artery may have preserved central vision in the unfortunate event of a CRAO.

Iris coloboma

Closure of the embryonic fissure begins at the equator and then proceeds anteriorly and posteriorly. This is analogous to neural tube closure which starts in the thoracic region and proceeds rostrally and caudally. Similarly, defects in closure at either end have different results. Cornea, iris or ciliary body coloboma results from failed closure anteriorly and defects in choroid, retina and optic nerve results from failed closure posteriorly.

Coloboma of the lens.

Coloboma of the lens.

Axenfeld Loop

Consist of ciliary nerves (posterior) with pigmented melanocytes along their nerve sheaths .

Peters' Anomaly pic

Decreased vision by way of blockage of the central visual axis due to the corneal opacification will lead to deprivation amblyopia. In addition, patient may suffer from glaucoma due to likely malformation of the angle structures as well as shallow anterior chamber. Treatment for spectacle correction and amblyopia treatment should be initiated as soon as possible. Complications Graft failure, infection, and steroid induced glaucoma. Prognosis Prognosis for maintaining clear graft after 2 years is a low 22% as reported in a study by Rao et al5. Due to the young age of the patients, it is believed that immunologic rejection is the most common cause of graft failure. Graft failure rates have been reported to increase when combined with lensectomy and vitrectomy. In addition, those with preexisting glaucoma have a poorer visual prognosis. Overall visual prognosis is poor after corneal graft with one study finding that less than one-third of eyes with Peters' have visual acuity better than 20/400. In that same study, predictors of poor visual outcome included stromal vessels and large corneal grafts >8mm.

12 yold severe distress his mother states that the boy having ruble breathing is urinating all over the pace and is sweating profusely .Bradycardia and miosis what treatment

Diarrhea Urination Miosis Bradycardia, Bronchoconstriction Emesis Lacrimation L Salivation , Sweating , Secretion Excessive patasympathetic activity Pralidoxime and or Atropine Classic insecticide is parathion which is an indirect acetylcholinesterase inhibitor

Phospholine iodide indirect cholinergic

Echothiophate iodide

WMS

Ectopia lentis joint stiffness heart defects broad head (brachycephaly) microspherophakia Opposite to Marfan who are tall, have long limbs and hyperflexible joints

Anatomy, Physiology and Biochemistry

Energy, in the form of ATP, is produced in the lens primarily through anaerobic glycolysis in metabolically active cells in the anterior lens. This process is necessitated by the fact that the oxygen tension in the lens is much lower than that in other tissues, given that oxygen reaches the avascular lens only via diffusion from the aqueous humor.

Toxic optic neuropathy

Ethambutol and Isoniazid(INH)

Gardner's syndrome

Familial adenomatous poly[osis ass with Colon Ca ,Lesiona are actually harmartomas and retinal lesions RPE hyperplasia and CHRPE Hypertrophy

CI in children

Fluoroquinolones have been associated with arthropathy due to adverse effects on cartilage development . Tetracyclines can cause permanent tooth discoloration by forming tetracycline -calcium complexes deposits

CN V1 branches

Frontal ,nasociliary and lacrimal Mnemonic is V1 is NFL

Axenfeld Anomaly and Syndrome

GONIO

Lower than plasma in AH

Glucose Ma++, K+, Mg, roughly the ame

Histo of AR

Histologically, patients with ARS have been found to have a monolayer of endothelial-like cells with a Descemet-like membrane extending from the cornea, across the anterior chamber and angle structures onto the surface of the iris. The membrane is typically found in the quadrant with associated the ectropion uveae/corectopia and the iris atrophy is found in the opposite quadrant

Quadrant from most to least have the highest density of neurons

ISNT

Nevus of OTA

Ipsilateral dermal melanocytosis and proliferation of dermal melanocytes in the periocular skin of CN V 1 And V 2 If an individual has both ocular and periocular skin findings he is said to have OCULODERMAL melanocytosis . 10% chance of Glc andd 1/400 will develop UVEAL MELANOMA

Rhodopsin

Is the most sensitive to the 510 (green light) wavelength of the electromagnetic spectrum .It demonstrates less absorption of blue and yellow light and cannot absorb longer wavelengths (red light) The rhodopsin gene is located on Chr 3 .Rhodopsin is the combination of OPSIN and Cis -11-retinaldehyde .Opsin is synthesized by the photoreceptors .The majority of rhodopsin is located in the plasma membrane outer segments (RODS)11-cis retinaldehyde is photolyzed in the photoreceptors to 11-trans -retinaldehyde.Light activated rhodopsin activates transducin which ultimately leads to a hyperpolarization of the cell .The 11 -trans is transported to the RPE that then recycles to 11 cis . The most common mutation associated with AD RP is a rhodopsin mutation called P23H.Helps protein folding and its defect leads to an accumulation of rhodopsin in the rough endoplasmic reticulum. OPSINs are involved in color vision .There are three types of opsins in the normal person. M,(green ) S (blue ), L (red) cones Each of these photopigments has a different sensitivity to light of different wavelengths, and for this reason are referred to as "blue," "green," and "red," or, more appropriately, short (S), medium (M), and long (L) wavelength cones, terms that more or less describe their spectral sensitivity Gene defects in the L and M cones genes lead to re/green color vision deficits.The L and M cone opsins are located in the X chr. , this explains by most color deficient patients ate MEN, having a red/green deficiency.

Abducens nerve palsy.

Isolated paralysis of the abducens nerve causes horizontal diplopia, forcing the affected eye to orient inward, (i.e., medial deviation of the eye). The affected patient turns the head horizontally toward the ipsilateral shoulder for forward vision.

Trochlear nerve palsy.

Isolated paralysis of the trochlear nerve, an uncommon event, forces the eye to rotate upward and inward. Clinically, this results in vertical diplopia, which is made worse when the eye is directed downward and inward. Classically, such patients complain of difficulty while walking downstairs, the head often tilted down and toward the contralateral shoulder.

Edinger-Westphal nucleus

It supplies preganglionic parasympathetic innervation to the ciliary muscle and pupillary sphincter

What are the Glycosaminoglycans found in the cornea

Keratan sulfate , Chondroitin sulfate and dermatan sulfate

SOF

LTFs

Higher AH than plasma

Lactate Ascorbic acid Ca++ most of the protein is Albumin and transferrin

Lens crystallin

Largest Alpha ( anti oxidant to maintain the clarity of lens with age) 33% Beta -crystallin 55% of th water soluble proteins in the lens , Gamma = crystallin are and are concentrated in the nucleous The smallest crystallin comprise 15%

LHON

Leber hereditary optic atrophy is a mitochondrially inherited (transmitted from mother to offspring) degeneration of retinal ganglion cells (RGCs) and their axons that leads to an acute or subacute loss of central vision; this affects predominantly young adult males.

Radiation sensitivity

Lens <5Gy cornea , conjunctiva . lacrimal gland <50Gy Retina >55Gy Optic nerve Sclera tolerates more tha 1000 Gy

Goblet cells in conjunctiva

Mucin fills the spaces between the microvilli of the corneal epithelium cells to provide a uniform surface .Other functions of the mucin layer are: Lowers the surface tension of the tears film thus stabilizing it lubricate the eye lids as they traverse the globe during blinking Trap foreign particles on the surface of the eye , Changes the corneal epithelium from a hydrophobic layer to a hydrophilic one one , resulting in an even distribution of the tear film.

Anticholinergics are

Mydriatics and cycloplegics

Neural cell Migration

Normal corneal development depends on neural crest migration which occurs in 3 distinctive waves during embryogenesis to produce the structures of the anterior chamber. This typically occurs during the 7th week of gestation. The first wave involves the formation the corneal endothelium as the neural crest cells migrate between the surface ectoderm and the lens. The second waveforms form peripheral neural crest cells migrating between the newly formed corneal endothelium and surface ectoderm to form the keratocytes that will lead to formation of corneal stroma. The final wave involves formation of the iris stroma. Any disruption of neural crest migration or separation can lead to an anterior segment dysgenesis.

Blood supply to the intracanalicular portion of the ON

OA

Intracranial

OA and ICA

Rubella 1st trimester

Ocular (cataracts ) Auditory (deafness) Systemic (cardiac) second semester salt and pepper fundus

Where is the ultimate source of the basal layer of the corneal epithelium

Palisades of Vogt is 1-2 mm posterior to the corneal limbus where the conjunctiva and the Tenon's capsule fuse .

Pupil pathway

Pathways mediating the pupillary light reflex. The axons of the retinal ganglion cells project to

AREDS2

Patients with intermediate AMD(defined as extensive intermediate drusen , ONR LARGE DRUSEN, or non subfoveal geographic atrophy ) in one or both eyes benefited from treatment with reduction in progression to advanced AMD/Also Patients with a history of Advanced AMD in one eye benefit from AREDS vitamins to protect the other eye.

poisoning caused by organic phosphorus pesticides boy or individual in a farm , trouble breathing urinating , all over the place bradycardia MIOSIS

Pralidoxime injection is used together with another medicine AND OR ATROPINE to treat poisoning caused by organic phosphorus pesticides (e.g., diazinon, malathion, mevinphos, parathion, and sarin) and by organophosphate chemicals ("nerve gases") used in chemical warfare. Parasympathetic hyperactivity DIARRHEA URINATING MIOSIS BRADYCARDIA, BRONCHOCONSTRICTION EMESIS LLACRIMATION SALIVATION, SWEATING , SECREATION

Properties

Properties of Rod and Cone Systems Rods Cones Comment More photopigment Less photopigment Slow response: long integration time Fast response: short integration time Temporal integration High amplification Less amplification Single quantum detection in rods (Hecht, Schlaer & Pirenne) Saturating Response (by 6% bleached) Non-saturating response (except S-cones) The rods' response saturates when only a small amount of the pigment is bleached (the absorption of a photon by a pigment molecule is known as bleaching the pigment). Not directionally selective Directionally selective Stiles-Crawford effect (see later this chapter) Highly convergent retinal pathways Less convergent retinal pathways Spatial integration High sensitivity Lower absolute sensitivity Low acuity High acuity Results from degree of spatial integration Achromatic: one type of pigment Chromatic: three types of pigment Color vision results from comparisons between cone responses

Aniridia

Remember that aniridia is not the lack of iris .Rather the majority of cases have a residual stump of iris that often overlaps the trabecular meshwork and leads to Glaucoma .His parents have normal irises which;leads you to conclusion that this is a sporadically inherited aniridia , GU defects and ID are associated with nonfamilial form o f aniridia (WAGR}Therefore an abdominal US must be administered to rule out a Wilms Tumor

11-cis retinal phototransduction

Representation of molecular steps in photoactivation. Depicted is an outer membrane disk in a rod. Step 1: Incident photon (hν) is absorbed and activates a rhodopsin by conformational change in the disk membrane to R*. Step 2: Next, R* makes repeated contacts with transducin molecules, catalyzing its activation to G* by the release of bound GDP in exchange for cytoplasmic GTP, which expels its β and γ subunits. Step 3: G* binds inhibitory γ subunits of the phosphodiesterase (PDE) activating its α and β subunits. Step 4: Activated PDE hydrolyzes cGMP. Step 5: Guanylyl cyclase (GC) synthesizes cGMP, the second messenger in the phototransduction cascade. Reduced levels of cytosolic cGMP cause cyclic nucleotide gated channels to close preventing further influx of Na+ and Ca2+.

Reverse cutting

Reverse cutting i. Configuration similar to the conventional cutting needle except that the 3rd cutting edge is outside the needle I. Triangular with cutting edge at bottom of needle. II. Cuts at tip and three edges of needle. ii. Characteristics I. Suture canal extends deep to path of needle tip. II. Advantageous for full-thickness suturing of tough tissue (facilitates tissue penetration) III. May inadvertently perforate tissue during partial-thickness suturing (e.g., sclera during strabismus surgery)

Laminar nerve

SPCA(20) and brancles of circle Zinn -Haller

Retrolaminar nerve

SPCA(20) pial vessels

Prelaminar nerve

SPCA(20)and recurrent choroidal arteries

It is on the differential for congenital corneal opacifications. S.T.U.M.P.E.D

Sclerocornea tears in Descemet's ulcers metabolic Peters' endothelial dystrophy dermoid.

spheno-ethmoidal recess superior to the superior concha.

Spheroid sinus

medial eyelid lymphatic drainage

Submandibular under the angle of the jaw near the carotid

Most common quadrant for scleral rupture

Superonasal near the limbus Other sites Ina circumferential arc parallel to the corneal limbus in the quadrant opposite the site of impact At the insertion of the rectus muscles At the equator of the globe

Drainage system , aclera except the temporal portion with is meso(fibers of the EOM ), and the crystalline lens

Surface Ectoderm

Aqueous humor passes

TM into Schlemm's canal ,from there aqueous flows into the collector channels , then to deep and midscleral venous plexus and then to the episcleral venous plexus. The blood then drains into the anterior ciliary veins to SOV to cavernous sinus

The uveal tract is attached at 3 sites:

The choroid is part of the uveal tract which includes the iris and ciliary body as well. The uveal tract is attached at 3 sites: 1. the scleral spur 2. internal scleral exit channels of the vortex veins(internal ostia of the VV)Explains the dome configuration of the choroidal hemorrhages 3. optic nerve

Ciliary Body Histology

The histologic sections of ciliary muscle show pink smooth muscle bundles (number 2); some are longitudinally oriented toward the scleral side and others are more circular toward the vitreous. The ciliary muscle is responsible for accommodation. The ciliary epithelium is composed of the inner non-pigmented layer (barely visible here at arrow 4) and outer pigmented layer (arrows 3) . The aqueous is made by the non-pigmented epithelium. The beginning of the pars plicata shows the undulations in the ciliary epithelium. Sclera as marked forms the outer tunic.

What type of ciliary muscle attaches ti the scleral sour and upon contracture causes the TM to open

The longitudinal and circular muscle .That is how Pilocarpine works .

NPECB

The posterior pigmented epithelial layer of the iris is a continuation of the NPECB and thus the neurosensory retina .The pigmentation of this posterior epithelial layer of the iris begins mid gestation at the papillary margin and proceeds periphery .Derived from the Neuroectoderm . The posterior pigmented layer of the iris curves around the margin for short distance onto the anterior border of the iris stroma to give rise to the pupillary RUFF> apex -apex orientation the basal srface is adjacent to the posterior chamber . lens zonules originate from the basal lamina of the NPECB Aqueous humor is secreted by the NPECB The intercellular tight junction (zonula occludens ) between the apices of the cells of the NPECB form the major element of the BLOOD _AQUEOUS BARRIER

BOW region

The region of the crystalline lens that is formed from the nuclei of new , elongating fibers then expresses a protein called the major intrinsic protein (MIP)which presumably is correlated with the elongation of the fibers . Cells elongate and the points where the cells from one side touch the cells from the opposite side form the sutures after this the cells lose their nuclei . The cells form from birth to age 20 years old form the center of the lens and are referred to as the nucleus . The cells on the outside of the lens formed after the age of 20 year sold are referred as the cortex .

Histopathology:

The same principles seen in the gross examination apply to histologic sections for diagnosis. The relationship of the sclera spur (arrow #1) reveals the posterior displacement of the iris-ciliary body complex. Residual meridional ciliary muscle strands are seen attached to the sclera (arrow #2). The effaced ciliary muscle shows pigment as it is reflected posteriorly (arrow #3). Angle injury to the outflow tract is indicated by pigment laden macrophages and fibrosis over the trabecular meshwork (arrow 4). The remaining attached longitudinal ciliary muscle is evident at arrow # 5. Circular muscle fibers are seen at arrow #6. Radial ciliary muscle fibers are evident at arrow #7. Secondary complications of angle recession include obstruction of the trabecular meshwork by synechiae or endothelialization over the trabecular meshwork. The synechiae are sequelae of inflammation and hemorrhage. Endothelialization may reflect injury to the cornea. The final result is glaucoma, which if untreated may result in glaucomatous atrophy (see image below). Treatment: The glaucoma is treated as open angle glaucoma. Some have indicated that trabeculectomy with antimetabolite therapy is more effective than other surgical treatment in these patients. (Ref. 3) Prognosis: About 6% of patients develop glaucoma after angle recession from the mechanisms of trabecular meshwork obstruction described above. Additional mechanisms include damage and scarring to the outflow apparatus, cataract and phacolytic glaucoma.

Crystalline Lens sutures

These sutures represent the ends of the lens fibers (from opposite sides of the lens )interdigitating with each other at the anterior and posterior lens poles

Sympathetic chain to the eye

Three orders 1) Hypothalamus to ciliospinal center of BUDGE-Waller 2) From the ciliospinal center to the superior cervical ganglion 3) From the superior cervical ganglion to the iris dilator muscle

Wht serves as the basis for the EOG

Trans -RPE potential The Apical surface of the RPE has the Na+ K -ATPase transports ions from the subretinal space into the RPE cells .The net flow of ions across this apical surface created an electrical potential that can be measured .This is the basis of the EOG .the macular lesion looks like . Best disease is an AD dz cause by mutations VMD2 gene , Best dz he or she will have an abnormal EOG and normal ERG regardless of what This gene encodes the protein "BESTROPHIN"which i a transmembrane chloride channel located in the basolateral membrane of the RPE

Peters' Anomaly pic 2

Treatments for Peters' anomaly aim at clearing the central visual axis to allow for visual maturation. Full thickness penetrating keratoplasty is the current standard of care. Iridoplasty for reformation of iris and cataract extraction for those with lens involvement.

How many decussations are there in the pupillary reflex pathway

Two One in the optic quiasma One in the pretectal nuclei

What is the major collagen of the stroma

Type 1 70%

Sclera

Type 1 collagen mostly and proteoglycans , decorin , biglycan and aggrecan The outer 2.3 of the sclera merges with the dura of the optic nerve sheath .The strongest points of the scleouveal attachments are the major emossarial canals and the anterior base of the CB

Types of hypersensitivity reaction

Type I IgE Allergic conjunctivitis Type II Cytotoxic Ab OCP Type III Immune complex reactions SJS Type IV are delayed hypersensitivity reactions >these involve recruitment of pre-sensitized immune cells . Contact dermatitis Type V stimulatory hypersensitivity MG/Graves

Prodrug of acyclovir

Valacyclovir has much higher bioavailability

vagus nerve

When someone tells you to relax or you try to breathe deeply to calm down from a tense situation you are hoping to stimulate of the vagus nerve which controls much of our ability to chill out.

Keratocyte( 2.4 million predominant cell in corneal stroma )

a modified fibroblast which produces collagen .Are flat in profile ensures minimal disturbance in transmitted light

Physostigmine indirect cholinergic

act inhibiting acetylcholinesterase

Main refractive element of the eye

air -tear interface positive lens approx. 43 Diopters

A-R syndrome(FOXC1 and PITX2 )

also known a mesodermal dysgenesis , is a group of congenital anterior segment defects that lead to glaucoma 50% of cases .It is often AR and is associated with mutations in the PITX2.In AR there is always a prominent Schwalbe's line(posterior embryotoxon).Other ocular signs include correctopia , iris holes , iridocorneal adhesionand ectropion uvea. Systemic findings in AR include Maxillary hypoplasia , redundant periumbilical , hypospadias and teeth abnormalities including absent teeth (hypodontia )and small teeth(microdontia) AR is caused by abnormal migration of neural crest cells which are required for the normal development of the anterior segment . , migration, or arrested development of neural crest cells in the anterior chamber, facial bones, teeth, cardiovascular system, and periumbilical skin are considered to be the etiological basis for the systemic and ocular findings characteristic of ARS.

Pilo, Miochol and Miostat

are direct Cholinergic acting

Adrenergics agents

are generally mydriatics .

anterior ciliary artery

arises from the OA

Type III collagen

associated with stroma wound healing

Rieger anomaly,

associated with systemic findings, such as dental, facial bone defects including maxillary hypoplasia, umbilical abnormalities, or pituitary involvement is known as Rieger syndrome. The combination of Axenfeld anomaly and Reiger syndrome is known collectively as Axenfeld-Rieger syndrome.

Ventral ophthalmic artery

becomes the nasal long posterior artery

Ventral OA

becomes the nasal long posterior ciliary artery

Dorsal ophthalmic artery

becomes the ophthalmic artery at around the sixth week of gestation .

Intraorbital

branches of the CRA, pial vessels and branches of the OA

CB

cells are arranged nonpigmented and pigmented epithelium apex nonpigmented to apex of pigmented

Lowe syndrome two most common findings

congenital cataracts and glaucoma. also renal tubular dysfunction and ID

Tertiary vitreous

consist of the zonular fibers which hold the lens in place

Blessing-Iwanoff

cyts near the ora serrata is very thin and the ora is closest to the limbus 5.75 mm

Peters anomaly histo

defect in Descemet's membrane and endothelium . Histologically, Peters' type I has an absence of Descemet's membrane and endothelium in the area of the corneal opacity with underlying iridocorneal synechiae. The overlying stroma, Bowman's layer and epithelium are rarely involved. The opacification often involves the central cornea, however, can affect the entire cornea. Peters' type II will have lens abnormalities that can be seen histologically.

NADH dehydrogenase

deficient LHON This leads to an abnormality of the mitochondrial NADH dehydrogenase and thus impaired ATP production .High energy dependent tissues like the ON re severely affected

Fetal ETOH syndrome

delayed growth ID abnormal behavior patterns majority have optic nerve hypoplasia

Middle meatus

drain Frontal , anterior and medial etmoidal,and maxillary

Muller cell

extends from the ILM to the ELM of the retina

Waves of AC formation

first K endo second iris and pupillary membrane third corneal stroma and sclera TM from the neuroectoderm

Dermatan sulfate

found ii skin , blood vessels , tendons lungs

Keratan sulfate

found in cornea and other connective tissue

The fourth cranial nerve (trochlear nerve)

has the longest intracranial course and is the only cranial nerve that has a dorsal exit from the brainstem (figure 1). It begins in the midbrain at the level of the inferior colliculus as fascicles extending from the fourth nerve nuclei.

Glucose

i the main metabolic substrate for the K epi , stromal keratocytes and the endo. 90% from the AH amd 10% from the tear film and limbal; blood vessels

Round taper-point needle

i. Configuration I. Round shaft tapered to a point. II. Cuts at its tip only. ii. Characteristics I. Atraumatic II. Leaves smallest hole of any needle style III. Use in easily penetrable tissue where tissue trauma must be minimized (e.g., iris sutures) Type of point TAPER - these points "push" through tissue and thus produce the smallest holes . Example Ethilon BV100 the is used frequently for watertight closure of conjunctival wounds in trabeculectomy .Taper point neddles have a very difficult time "pushing " through tougher tissue s like cornea and sclera

Cutting

i. Configuration I. Triangular with cutting edge at top of needle and inside II. Cuts at tip and three edges of needle. ii. Characteristics I. Suture canal extends superficial to path of needle tip. II. May pull out of tissue as needle is passed and bigger holes .

Spatula

i. Configuration Trapezoidal -shaped needle that cuts on its point and sides and not at the bottom . These needles facilitate partial-thickness passes and thus are used in operations involving the cornea or sclera.The ability to maintain partial-thickness depth helps aligning tissue ends(PKP) and also prevents the surgeon from accidentally perforating the globe during scleral passes (Stab or scleral buckling suture ) Ethilon VAS 100,TG140 and TG160 I. Four- or six-sided with cutting edges on the sides. II. Cuts at tip and sides parallel to tissue plane. ii. Characteristics I. Displaces tissue above and below needle, avoiding inadvertent penetration of tissue as needle is passed. II. Maintains needle in tissue plane. III. Most frequently used microsurgical needle style

Neuroectoderm

inner NP layer

Heparins/Heparan sulfates

involved in coagulation , angiogenesis , developmental

Pilo4%

is CI in acute angle closure glaucoma because it shifts the lens iris diaphragm forward . Pilo 1%

Ganciclovir

is not a prodrug but instead must be phosphorylated (viral thymidine kinase ) to become activated.For CMV use is restricted due to is to its sever side effect profile(myelosuppression)

UVA

is thought to penetrate deeper into the lens Gluthatione is the major oxygen scavenger found in young people that diminishes with age

Which needles

is typically best for suturing the corneal or sclera Are defined by their shape /curvature as well as their points . 1/8 circle (45 degrees) !/4 circle( 90 degrees) 3/8 circle ( 135 degrees) most common needle 1/2 circle (180 degrees) 5/8 circle ( 225 degrees ) Bi -Curve Compound curve Straight Type of point TAPER - these points "push" through tissue and thus produce the smallest holes . Example Ethilon BV100 the is used frequently for watertight closure of conjunctival wounds in trabeculectomy .Taper point neddles have a very difficult time "pushing " through tougher tissue s like cornea and sclera

Thinnest part of the sclera

just posterior to the EOM insertions 0,3 mm Thickes t aound the optic nerve 1.0 mm

Responsible for majority of resistance aqueous in TM

juxtacanalicular is directly adjacent to the canal

carbonic anhydrase enzyme

more than 99% of this enzyme must be inhibited before significant decrease of IOP.

Chondroitin sulfate

most abundant GAG in the body , found in cartilage , bones , tendons and ligaments

LENS PLACODE

originates from the Surface Ectoderm

Leukotriene B4

oxygen radical formation and lysosomal enzyme release

Peripheral arterial arcade of the eyelid

peripheral arterial arcade between sandwich levator and Muller's muscle

Rifampin

pink -tinged tears and also blepharoconjunctivitis

Superior meatus

posterior etmoidal

Where is the germinative zone if the lens epithelium

pre-equatorial region epithelial cells in the germinative zone ( anterior to the equator )

Embryonic vitreous

primary consist of the Hyaloid artery , vasa hyaloidea propria , some mesenchymal cells and the tunica vasculosa lentis . At approx. pth week gestation the secondary vitreous replaces the primary vitreous

Famciclovir

prodrug of penciclovir

HYaluronates

skin , vitreous , cartilage

Epinephrine is an adrenergic agent

so is mydriatic not cycloplegic

Ionic composition of the lens

sodium low and K +high The Na+/K+ATPase (sodium-potassium adenosine triphosphate ) regulates the ionic composition inside the lens .This enzyme pumps OUT sodium of the lens and potassium INTO the lens .Therefore , relative to the aqueous , sodium levels are low (10 nmo/L) and potassium levels are high (120 mmol/L) inside the lens . This gradient creates an ionic current IN at the anterior and posterior POLES and OUT at the equatorial region

What fatal side effect ha been most associated with systemic Mannitol and or Urea that are utilized to acutely decrease elevated IP.

subarchnoid hemorrhage due to acute volume overload and or rapid brain shrinkage which perhaps places traction on the subarachnoid vessels . Te orderly are increased risk for this fatal side effects since their brain is already shrunken .

lateral eyelid lymphatic drainage

superficial preauricular nodes into the deeper cervical nodes

Ophthalmic artery

supplies the short posterior ciliary arteries ,central retinal artery and thee temporal long posterior ciliary artery.

Accommodation

the ciliary muscles contracts and the lens obtains a more Spherical shape . In a relaxed state the CB muscle has a larger diameter and exerts tension on the zonules which in turn exerts tension on the lens and pulls it into a more disklike configuration. This allows one to see far .When looking up close the parasympathetic system activates .This causes the ciliary muscle to contract and adopt a smaller diameter .The zonules then have less tension placed on them and the lens is now under little tension .In its natural state with no tension placed on it, the lens adopts a more spherical configuration , increasing its diptic power and allowing for vision up close

Infant with allergy to eggs

vaccines to avoid MMR Influenza Rabies yellow fever CAN GIVE HEP B Vaccines to give ASPLENIC patients Meningococcal Hib Haemophilus influenza) Pneumococcal

Some basic cavernous sinus region anatomy,

with arrow color designated in brackets. Cavernous sinus (blue), optic chiasm (yellow), pituitary gland (red), infundibulum (orange), cavernous carotid (purple), intra cavernous portion of cranial nerves 3-5 (brown). The cavernous sinus also contains several critical structures - the internal carotid arteries, cranial nerves 3, 4, 6 and the first two branches of 5. Most of the cranial nerves run along the wall of the sinus which is formed by dural reflections at the skull base. Only cranial nerve 6 runs within the cavernous sinus and as such is the most likely nerve to be affected by cavernous sinus pathology. As the cavernous sinus is partly responsible for venous facial drainage, facial infection can result in cavernous sinus thrombosis, a potentially devastating condition. The normal cavernous sinus should enhance avidly on MRI - any lack of enhancement should raise the question of thrombosis