Surgery Flashcards
DDX of orbital inflammation
- infectious
- bacterial - be wary of TB and nec fas
- autoimmune
- TED
- IgG4
- vasculitic
- wegners
- GCA
- PAN
- other
- granulomatous
- sarcoid
- NSOI
Intraocular calcium
- PFV
- Phthisis
- RB
- retinocytoma
- osteoma
Toric lens rotation
- each degree of rotation decreases toric lens astig by 3% OR
10 degrees off axis decreases by 1/3 OR at 45 degrees cyl power is nil
IOL power and refractive error
1D error in value of lens equals 0.67 D in refractive error
unilateral cataract DDX
idiopathic
masked bilateral
rubella
traumatic
ocular abnormality: PFV, ant seg dysgenesis, post lenticonus, post pole tumour
Drugs and cataracts
steriods
phenothiazines
amiodarone
statins
tamoxifen
pilocarpine/echothiophate
Post op CE IOL see increased inflam
PXF
PDS
DM
kids
prev surgery
prev pilo
Floppy iris sydrome
adrenergic antagonists
Ex: Tamsulosin (alpha 1a antagonist), antihypertensives: Doxazosin, Terazosin, Prazosin, labetalol, antipsychotics: chlopromazine
Triad: miosis billowing prolaps
signs of explusive SCH
dark red reflex
incision gape
iris prolapse
expulsion of lens/v/blood
Risk factors for CME
- VMT
- UV light
- PCR
- v loss
- iris prolapse
- hypotony
Risk of endophthalmitis
- wound leak
- V loss
- DM
- PCR
- prolonged surgery
SEE TABLE
Risk factors for ret detachment
axial myopia
younger age
male
lattice
prev tear
fam hx of RD
qualities of visco elastics cohesives (healon, amvisc) vs dispersives (viscoat, cellugel)
self adherence
viscosity/molecular mass (higher resists more force) (ability to resist flow or force)
surface tension/coating
ease of aspiration
Refractive surgery numbers
Munnerlyn: myopia x optical zone2 / 3
large pupils increase risk of glare
EBMD increase flap complications
conj scar incrase issues with microkeratome suction
Flat k - <40D small flap and free caps
Steep k - >48 button hole flaps
<34 or >50 ks = poor quality va …. for myopia substract 80%, for hyperopia add 100%
Need to leave stromal bed 250
RK incisions 90% thickness - get diurnal flucuation of vision and progressive flattening effect
coupling ratio: amount of flattening in the meridian of the incision divided by the induced steepening in the opposite direction…if 1- then SE unchanged, if + ratio- greater than 1 then hyperopic shift occurs
AK: 95% depth in steep meridian at 7mm optical zone
LRI: 600 um depth just anterior to limbus
PRK and LASIK treat -14- + 6
** to increase effect of LRI, increase length of incision, to increase effect of AK increase length, depth, use multiple incision, reduce the distance between incisions, make it more central
ortho K
overnight use of rigid has perm CL that are fitted at base curve flatter than K curvature…causes temporary flattening of K epi to treat myopia
approved for -0.50–> -6 with up to 1.75 astig
do not treat hyperopia or astig
in studies 1/3 had to discontinue and 75% experienced pain
complications: astigmatism, HOA, recurrent erosins, IK
PRK vs LASIK
PRK
- who can get it : irregular or thin corneas, EBMD , previous K surgery (PKP RK), treatment of LASIK flap complications
- eliminates potential for stromal flap related complications and HOA
- may have decreased incidence of dry eye and ectasia
- corneal haze is major risk, has decreased with MMC (see more with higher refractive error)
- increased risk of infection compared to lasik due to longer epi healing
- cx: persistent epi defect, sterile infiltrates, K haze
LASIK
- faster visual recovery
- decreased photoperative discomfort
- cx: microkeratome, epi sloughing or defects, striae, traumatic flap, DLK, PISK, epi ingrowth, interface debris, ectasia
*** Lasik wait 3 mo for retreatement, PRK wait 6 mo for retreatment
epi ingrowth increases in
- epi defect at time of procedure
- re treatment with lifting of pre existing flap
- traumatic flap dehisence
antibiotic choices
3 year old - preseptal cellulitis, sinus origin?
amox-clav 40mg/kg/day po div bid consult ENT
pen allergic: septra8/60 mg/kg div bid
Adult - Preseptal cellulitis, from lid wound?
if mild Amox-Clav 875/125 mg po bid
pen allergic: TMP/SMX DS 1-2tabs po bid.
Adult - preseptal cellulitis CAMRSA ?
Suspect MRSA TMP/SMX DS 2 tabs po bid
Suspect MRSA clinda 400 mg po TID
Adult- pre septal cellulitis HA MRSA?
vancomycin or linezolid
5 year old with mild pain with EOM, N vision and small Subperiosteal Abcess (SPA).
Cefrtiaxone 100mg/kg/day IV div q12 + Vanco 60mg/kg/day IV div q6 +/- metronidazole 30mg/kg/d IV div q8h.
10 year old with enlarging SPA on CT, increasing proptosis and slight decrease in colour vision.
Start IV Abx as above but consider lateral canth/cantholysis and book for urgent drainage.
Adult with orbital cellulitis, no vision or EOM compromise. Vancomycin 1g q12 h + Ceftriaxone 2g IV q12h + metronidazole 500mg IV q8h
Nec Fas: broad spectrum gram negative and gram positive and anaerobes and clindamycin
patient with blepharospasm during cataract surgery, what do you do?
van Lint block (A)
Anesthetize the terminal branches of the facial nerve
1.5inch, 25-gauge needle is inserted 1 cm lateral to lateral orbital rim as well as superior and inferior orbital margins, inject 3-6cc total
O’Brien (B)
Anesthetize the facial nerve at proximal trunk, done at the level of the neck of the mandible near the condyloidprocess just anterior to the tragus of the ear.
1inch, 27-gauge needle inserted at center of condyloid process to periosteum; inject 3 cc
Nadbath-Ellis block (C)
Anesthetize the facial nerve where it emerges from the stylomastoid foramen
Insert 5/8inch 25-gauge needle into the tympanomastoid foramen, inject 2-cc
Atkinson
This was introduced to overcome the disadvantage of Van Lint and O’Brien’s block. Van Lint causes ballooning and distortion of the lids and ocular adnexa while that of O’Brien produces postoperative pain at site of anaesthesia . The superior branch of the facial nerve is blocked by injecting the anaesthetic solution at the inferior margin of zygomatic bone subcutaneously with a 23g needle .
adverse events associated with nuclear fragment dislocation or v loss
Increased risk of endophthalmitis
increased risk of retinal tear and detachment
uveitis
K edema
increase post-op CME increase
increased risk of sub-optimal post-op visual recovery
risk of elevated IOP
vitreous opacities
recall: if PC rupture associated with 2X endophthalmitis and 20X risk of RD
DSAEK over PK
No open sky results in decrease risk of Suprachoroidal hmg
Not full thickness means better wound integrity and less risk of rupture
Less risk of rejection
reduction in suture related problems
greater accuracy in selection of intraocular lens for triple procedures
Rapid visual recovery
Less induction of astigmatism
