Anterior Segment, Van Herick Angle Estimation, and Cornea

What is one of the most common findings of lids and lashes?

What is the definition of that condition?

What are the two major classifications of blepharitis?

Blepharitis

Family of inflammatory diseases

Anterior blepharitis, Posterior blepharitis

What are the three major causes of and associations with blepharitis?

Bacteria, Staphylococcus, Skin disorder, Rosacea, Seborrhea, Parasitic, Demodex

What two things does the prevalence of blepharitis increase with?

Age (71% chance > 65, 3% in 18-22), CL wear (40% of CL wearers have bleph)

What are common symptoms of blepharitis?

Itching, matting of lids in AM, burning, pain, epiphora, FB sensation, redness, photophobia, dec VA

What other condition has some of these symptoms?

Dry eye has some of these symptoms

What does the clinical course of blepharitis look like?

Chronic course, Intermittent exacerbations of symptoms, Can get worse -> inc frequency of WC, lid hyg

What four characteristics of blepharitis would gross examination of eyelids show?

Erythema of margins, Crusting of lashes, Madarosis, Poliosis

What five characteristics of blepharitis would a slit lamp exam of lids and lashes show?

scurf/rosettes - Wrap around root of eyelash Inspissated glands - Clogged zeiss, moll, or MG

Frothy tears

Margin irregularities - Undulated, not smooth,

Margin telangiectasia - Small dilated bv -> erythema

What are inspissated glands characteristic of?

Posterior blepharitis, Meibomitis, MGD, Waxy excrescences

What does posterior blepharitis do to MGs overtime?

Normal -> moderate loss -> severe loss

How does saponification occur?

Bacterial lipases hydrolyze meibum, Creating soap -> foamy like substance in eyes

What is the typical control for blepharitis?

Warm compresses, Melt meibum out, Lid scrubs, Surfactant cleaners, Clear gunky meibum taken out by WC, NPAT - non-preservative artificial tears, Preservatives attack normal flora of eyes by dominating lubricant drops at higher amounts

What antibiotics are used for blepharitis?

Doxycycline po, Azithromycin gtts or po

Why Doxycycline po and Azithromycin gtts or po?

Antibacterial and anti-inflammatory, Preferred b/c blepharitis is not an infection - its an inflammatory response

What other bleph treatments are available?

Removing debris/exfoliation, Devices that meet MGs, Intense pulse light therapy, Affect superficial BV; inc tissue temp, Eliminate flora, Topicals, Hypochlorous acid, Natural antimicrobial agent produced by neutrophils, Demodex, Tea-tree oil extract, Xdemvy

Where does the slit lamp beam hit during van herick?

Focusing optic beam at limbus - 1 to 2 mm area b/w clear cornea and opaque sclera

What is measured during van herick?

Ratio of limbal anterior chamber depth to corneal width

What is angle closure?

Peripheral iris blocks TM outflow

Causing IOP to spike

Aqueous is produced 24/7 (at varying rates)

At night = lowest production - beta blockers less effective b/c dec in production

What is the order of angle depths for van herick and gonioscopy?

Van herick = estimated AC depth - ISNT (widest to narrowest); Gonioscopy = actual angle depth - ITNS

Why is the order different by van Herick angle estimation vs gonioscopy?

Van herick - Corneal shape = convex -> cornea steeper vertically -> optical section appears to have larger gap so chamber appears deeper and cornea is flatter horizontally -> gap appears smaller so it appears shallower; Gonio = actual angle depth

What does van Herick angle estimation depend on?

Distance from angle - if put beam closer to cornea -> appears wider; Angle appears more open when angle estimation performed farther from same angle

Why use van Herick angle estimation?

Over-estimates narrowness of angle; Grade 2 = occludable but unlikely to close; Must do gonio before angle becomes occludable

Where are corneal nerves more prominent? Where are they found?

More prominent near limbus; Found in the stroma

What two criteria must be met for the definition of a corneal ulcer?

Epithelial defect; Sub-epithelial infiltrate; Opaque base of WBCs

What are two types of corneal ulcers?

Infectious - infection-causing pathogen present; Sterile - no pathogen but body mistaken and mounts inflammatory reaction -> cellular damage

What are the differentiating characteristics of sterile vs infectious corneal ulcers?

Sterile - small, peripheral, multiple/arcuate, AC quiet, no discharge, mild pain, little to no K thinning; Infectious - large, central, single, AC rxn, discharge, pain, excavated

Why is a central location more likely to be infectious than a peripheral one?

Center has fewer immune cells to fight infection - need help for immune cells to migrate - needs more time; Corneal ulcer near limbus less likely to be infection b/c more immune cells

Why is a peripheral location more likely to be inflammatory than a central one?

More immune response from limbus

Why are multiple locations more likely to suggest a sterile problem?

Bacterial infection hard to start in cornea (like bacterial conjunctivitis); Wonder if patient is immune-compromised or not infectious

What four characteristics suggest marginal keratitis?

Peripheral infiltrates; +/- epi defect; 10/2 and 5/7 positions; Conj hyperemia; sterile!

What is treatment for marginal keratitis?

Bacterial colonization; Lid hygiene; Topical antibiotic; Inflammation; Topical steroid; No infection but will give steroid + antibiotic to prevent secondary infection from steroid use

What are axenfeld loops?

Normal anatomic landmark; Gray or white nodules; 3 mm posterior to limbus; Long posterior ciliary nerve; May share channel with artery

What are epicapsular stars?

Form of cataract; Fetal remnants; Brown dots/stars