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ChM > Refractive Surgery > Flashcards

Refractive Surgery Flashcards

1
Q

What is Prolate shape?

A

shape of the cornea where curvature is steepest at the center and flattens out. Nasal is more flat than temporal

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2
Q

what is placido based corneal topography?

A

measures anterior corneal radius of curvature and ESTIMATE total K power

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3
Q

How much of the total refractive power of the eye comes from the cornea?

A

2/3. Anterior K is very + power; posterior K is negative in power thereby reducing total K refractive power

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4
Q

what are wavefront aberrations?

A

measuring small aberrations on the cornea by shining light on to retina and then measuring the reflected waves and using small lenses to neutralize the aberrations.

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5
Q

what’s the most used wavefront sensor called?

A

Hartmann-Shack

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6
Q

What are Zernike polynomials? what are they expressed as?

A

mathematical formulas used to describe cornea aberrations on wavefront–expressed as root mean square error “RMS”

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7
Q

what are the three most important Zernike coefficients affecting visual quality?

A

spherical aberration, coma, trefoil.

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8
Q

What is Fourier analysis?

A

an alternative method of interpreting aberrometer results than Zernike. Fourier is more detailed

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9
Q

What are lower order aberrations?

A

Lower order are things like myopia (positive defocus), hyperopia (negative defocus), regular astigmatism (orthogonal and oblique defocus)

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10
Q

What are higher order aberrations?

A

more complex aberrations that dependent on pupil size.. increases as pupil dilates.

may increase after surface ablation

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11
Q

impact of surface ablation/LASIK on spherical aberration?

A

increases spherical aberration leading to pronounced halos. increases depth of field but decreases contrast sensitivity

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12
Q

what are the three types of OCT domains?

A

frequency, time, spectral

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13
Q

what are the two types of dry eyes?

A

aqueous tear deficiency, evaporative dry eyes

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14
Q

how do giant papillae form?

A

weakening of inter papillary septa over time

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15
Q

what is at the center of follicles?

A

germinal centers

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16
Q

what is benign lymphoid folliculosis?

A

normal follicles on inferior palpebral conj or in the fornix in young people

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17
Q

make up of KPs

A

fibrin/proteins, neutrophils, lymphocytes, macrophages (mutton fat clumps)

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18
Q

two types of stromal keratitis and causes?

A

suppurative vs nonsuppurative

suppurative: bacterial, fungal, acanthomoeba
nonsuppurative: rheumatoid, cogan’s, syphilis, lyme, TB, leprosy

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19
Q

whats the pathophys of evaporative dry eyes

A

MGD where unsaturated fats becomes saturated and obstructs the gland and leads to tear film instability

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20
Q

whats the pathophys of aqueous tear deficiency?

A

T cell mediated inflammation/destruction of lacrimal gland leading to decreased tear production and increased epithelial apoptosis

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21
Q

how wide is the normal tear meniscus

A

1 mm and convex

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22
Q

mucus discharge is frequent in which kind of dry eye

A

aqueous tear deficiency

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23
Q

when is Aqueous tear deficiency considered secondary to sjogrens

A

if theres hypergammaglobulinemia, collagen vascular disease, SSaSSb positive

24
Q

what is primary and secondary sjogre;s syndrome

A

primary has ill defined systemic disease process. secondary has well defined systemic disease process such as a rheumatoid condition

25
Q

which dry eye is worse in the morning and which is worse in the evening?

A

evaporative is worse in AM

ATD is worse in PM

26
Q

Categorization of MGD?

A

hypo vs hyper delivery. Hypodelivery then is hypo secretion vs obstruction. hypo secretion is due to cicatricial vs non cicatricial

27
Q

risk factors of dry eyes?

A

xerophthalmia, allergies, contact lens wear, high n6/n3 fatty acid ratio, DM, smoking, prolonged video, meds (especially glaucoma drops with benzalkonium chloride)

28
Q

MGD is often associated with what skin condition?

A

rosacea acne

29
Q

whats the mainstay of ATD treatment?

A

replacement therapy: ATs, gels, ointments, restates, xiidra, scleral contacts, autologous serum, moist chambers

30
Q

How to treat filamentous keratitis?

A

debride the filaments, supplement tears, punctal plugs, acetylcysteine 10% for mucolytic, low dose steroid/cyclosporin

31
Q

what are demulcents

A

mucomemetics in Its

32
Q

How long does restasis take to work. How long does xiidra?

A

restates is many months of consistent use. xiidra within a few weeks

33
Q

side effects of xiidra

A

irritation, transient blurry vision, dysgusia, should not insert CL for 15 mins

34
Q

what are the two cholinergic meds used for increasing tears and decreasing xerostomia?

A

pilocarpine, cevimeline

also can do omega fats to help

35
Q

what are some surgical options for ATD?

A

punctal plugs/cautery, lid/conj chalasis surgery, lateral/medial tarrsorrhaphy

36
Q

mainstay of MGD treatment?

A

eyelid hygiene–warm compress, lid massage, lid scrub,

37
Q

what are some adjuncts for MGD treatment aside from hygiene

A

short term azithromycin drop use to decrease bacteria burden, omega fats, PO tetracycline/doxy/minocycline (control disease but not eliminate), LipiFlow

38
Q

rosacea is associate with what organism. what’s the theory of pathogenesis

A

demodex–> increased canthelicidin –>inflammation–>dysfunction of sebaceous gland

39
Q

what are things that can exacerbate rosacea

A

alcohol, emotional stress, spicy foods, hot/cold environment

40
Q

features of ocular rosacea

A

recalcitrant chronic blepharitis, chalazion, excessive oil production, chronic conjunctivitis, stromal keratitis, sterile ulcers, episcleritis/iritis, corneal NV

41
Q

facial lesions associated with rosacea

A

mid facial erythema, telangiectasis, flushing episodes, malarkey rash, rhinopehyma

42
Q

mainstay of treating ocular rosacea?

A

PO tetracyclines (erythropoietin/azithro can be used if tetracyclines are contraindicated)

topical: metrogel and azelaic acid
Intense pulsed light therapy

43
Q

management of ulcerative keratitis in rosacea?

A

conservative is better due to poor prognosis. Can be infectious or noninfectious–can use steroids if determined to not be infectious.

44
Q

what is seborrheic blepharitis?

A

inflammation at the lid margin with scaling, scurf with greasy consistency, PEEs, evaporative dry eyes

45
Q

treatment for seborrheic blepharitis?

A

lid hygiene, selenium sulfide shampoo

46
Q

demodicosis is associated with what exam finding?

A

lash sleeving with refractory blepharitis

47
Q

how to treat democicosis?

A

tea tree oil, oral ivermectin

48
Q

staph blepharitis is seen in what population

A

young people.

49
Q

clinical finding of staph blepharitis?

A

collarettes, hard brittle fibrinous scales, and hard crusts matted around cilia, macaronis, poliosis, trichiasis

50
Q

what are two organisms commonly causing chronic blepharoconjunctivitis?

A

staph aureus and mortadella cunata.

51
Q

chronic angular blepharoconjunctivitis is caused by what organism

A

moraxella cunata

52
Q

staph marginal disease is usually at what clock hours?

A

2, 4, 8, 10

53
Q

what two organisms cause phyctenules?

A

staph aureus, TB

54
Q

hordeolum vs chalazion

A

hordeolum: inflammation of Zeiss or meibomian
chalazion: lipogranulomatous nodule of Zeiss or meibomian.

55
Q

hair loss over chronic chalazion is indicative of what?

A

malignancy–basal, squam, or sebaceous cA.

56
Q

intralesional injection of steroids can be done for chalazion… who should you not do it on.

A

dark skinned individual –can lighten skin in the lesion area.

ChM (59 decks)

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