1
Q
What are the symptoms of cataract
A
reduced VA
Loss of contrast sensitivity
Change in colour perception particularly with blue colours
Glare with light scatter
Monocular diplopia
Difficulty seeing in low light situations
2
Q
What kind of cataract leads to myopic shift
A
nuclear sclerotic cataract
3
Q
Why is the nuclear sclerotic cataract yellowish
A
deposition of urochrome pigment
4
Q
What is the function of the cuboid epithelial cells of the human lens
A
located beneath the anterior capsule and extend to lens equator; cells in germinative zone (equator) divide continuously and differentiate to form lens fibres
5
Q
What is the difference between immature, mature, hypermature and morgagnian cataract
A
immature- lens partially opaque
mature- lens completely opaque
hypermature- cataract shrunken and wrinkled anterior capsule due to leakage of water out of the lens
morgagnian- hypermature cataract liquefaction of cortex allows nucleus to sink inferiorly
6
Q
Why does diabetes mellitus lead to cataract formation and what are the classic types of cataract?
A
high glucose in aqueous humour- diffuse into lens. glucose metabolised to sorbitol accumulates in lens causing osmotic overhydration.
Rare: snowflake corticalo opacities. Age related cataract comes sooner in these patients. NS common- progress rapidly
7
Q
What sort of cataract forms in myotonic dystrophy?
A
90% develop fine iridescent cortical opacities in 3rd decade, sometimes resembling christmas tree cataract. Evolve into visually disabling wedge shaped cortical and subcapsular opacities in star like conformation by 5th decade
8
Q
What sort of cataract forms in atopic dermatitis
A
10% of patients with severe atopic dermatitis develop cataracts in the second- fourth decade. Bilateral and may mature quickly. Shield like dense anterior subcapsular plaque that wrinkles the anterior capsule. Posterior subcapsular opacities may occur
9
Q
What kind of cataract forms in NF2
A
early cataract in 60% patients. PSC cataract, or capsular/ mixed.
10
Q
What are some causes of secondary cataract
A
chronic anterior uveitis
acute congestive angle closure
high myopia (pathological myopia)
Hereditary fundus dystropies
Secondary to medications (steroids, chlorpromazine)
11
Q
If a patient had an MI when should cataract surgery be deferred to
A
3-6 months from date of MI
12
Q
If a patient had a stroke, when should cataract surgery be deferred to
A
at least 6 months from date of stroke
13
Q
What is the sight loss risk when counselling patients for cataract surgery
A
1 in 1000 operations eye left with little- no sight.
1 in 10,000 the patient will lose the eye
14
Q
What is the risk of PCR +/- vitreous loss, dropped nucleus, retinal detachment, endopthalmitis and suprachoroidal haemorrhage
A
PCR- 1% or less
Dropped nucleus 0.2%
RD- <1%
Endoph- 0.1%
Suprachoroidal haem- 0.04%
15
Q
Which biometry formula are good for eyes with AL <22mm shorter AL
A
Hoffer Q
Haigis
Hill RBF
Kane
16
Q
Which biometry formula are good for eyes with AL >26mm long AL
A
Barrets Universal II
Holladay
Haigis (with optimised constant)
Kane
17
Q
What are some formulas which help calculate biometry in post refractive surgery patients
A
Measure ‘true’ corneal power using refractive history method, contact lens method. Insert this into standard eg Hoffer Q, or Masket formula. But Haigis- L regression formula uses statistical data to facilitate calculation.
18
Q
How long should patients not wear contact lenses for prior to cataract surgery biometry
A
soft CL- upto 1 week prior
rigid gas permeable- upto 6 weeks
19
Q
What margin of error is acceptable in cataract surgery post op
A
post operative unaided refraction within 1D of predicted outcome 90% within 0.5D in 2/3rds
20
Q
What do most surgeons aim for post phaco IOL
A
-0.25
21
Q
What post op target should be considered when the fellow eye isn’t ready for phaco IOL yet
A
within 2D to prevent anisekonia or aim emmetropia and lens exchange fellow eye
22
Q
What is the concept of monovision post phaco IOL
A
non dominant eye 1-2 dioptres of myopia allow unaided vision for reading. Fellow eye emmetropia in dominant eye.
23
Q
What must patients younger than 55 be warned about with phaco iol
A
active focusing will be lost after the implantation of a
conventional monofocal IOL
24
Q
what is secondary pseudopolyphakia
A
supplementary IOL may be placed in the sulcus in addition to an IOL in the capsular bag, for instance to address a residual refractive error following primary surgery.
Avoid in nanophthalmic eye due to angle closure risk
25
What are some types of flexible IOL's
Acrylic
Silicone
Collamer
26
What is an example of rigid IOL
PMMA- cant be folded- need larger corneal incision 5-6mm
27
What are the differences between hydrophobic and hydrophilic acrylic IOL's
hydrophobic- greater refractive index, thinner. So can cause dysphotopsia (glare and reflections). Greater reaction in eyes with uveitis. Hydrophilic offers superior biocompatibility but risk of calcification requiring IOL removal and inflammation.
PCO risk higher with hydrophilic IOL's
28
What are the benefits of heparin coated IOL's
reduces attraction and adhesion of inflammatory cells. This is good for eyes with uveitis
29
What is the advantage of aspherical optics in IOL's
counteract spherical aberration and improve contrast in mesopic conditions.
30
What does a high Aspiration flow rate (AFR) do
Increased attraction of lens material towards the phaco tip with faster vaccuum build up and swifter lens matter removal but with less effective power
31
What does vaccuum adjustment on phaco machine do
generated during occlusion when pump attempting to aspirate fluid. determines how tightly material is held by phaco tip when occluded providing ability to manipulate lens fragments. High vaccum can decrease total power needed to remove the lens
32
What is post occlusion surge
when occlusion of phaco tip by lens material is broken, pent up energy results in sudden temporary outflow increase 'surge'. Result in PCR. Modern phaco machines suppress this
33
What is the difference between peristaltic and venturi pump
peristaltic flow pump- pull fluid and lens material into phaco tip by compressing tubing over variable speed rollers. vacuum generated when occlusion of tip occurs
Venturi creates a negative pressure in vessel by passing compressed gas across its entrance. This syncrhonizes vacuum and AFR so no independent means of adjusting AFR
34
What are the different types of OVD's
Cohesive- create and maintain intraocular spaces - maintain space during capsulorhexis and inflation of bag for IOL. Lead to prolapsed iris as high molecular weight. Confer more sustained post operative IOP rise.
Dispersive- more adherent to surfaces protect endothelium- more difficult to remove from eye less likely to cause IOP spike. They retain air bubbles and lens fragments compromise view
Adaptive OVD- mixed characteristics
35
What is the soft shell technique
Injection of outer dispersive layer followed by inner cohesive layer. Used for eyes with high risk of corneal decompensation eg corneal guttata
36
What steps in cataract surgery can femtosecond lasers help with
corneal incisions
capsulorhexis
initial fragmentation of lens
astigmatism relieving incisions
37
What are the signs of PCR intraop
sudden deepening or shallowing of AC and momentary pupil dilation
Nucleus falls away and cannot be approached by phaco tip
vitreous aspirated into phaco tip causes slowing of aspiration
torn capsule/vitreous can be visualised
38
What drugs can help with vitreous visualisation
trypan blue
triamcinolone
39
If placing a sulcus lens- how should power modifications be done for the IOL
With rhexis capture original planned IOL power or possibly less 0.5D can be used (weaker power). Without capture reduce by 0.5-1D
40
What are the risks of AC IOL's compared to PC IOL's
pupil block if PI not done.
bullous keratopathy
hyphaema
iris tuck
pupil irregularities
41
What is a suprachoroidal haemorrhage
bleed into suprachoroidal space from ruptured posterior ciliary artery. Can result in extrusion of intraocular contents (expulsive). 0.04% risk with phaco.
42
How is suprachoroidal haemorrhage managed post initial closure
if spontaneous absorption fails to occur, drainage needed 7-14 days after by which time liquefaction of blood clot has taken place. Visual prognosis is variable. prolonged chorioretinal apposition >14 days reduces prognosis. PPV can be done if retina adherent/detached. Apposed kissing haemorrhages may resolve spontaneously without apparent retinal problems
43
What are the risk factors for post operative endophthalmitis
PCR
Prolonged op time
Combined procedure eg with vitrectomy
Clear corneal sutureless incisions
temporal incision
wound leak on day 1
delaying post operative topical antibiotics until 1 day post op
topical anaesthesia
adnexal disease and diabetes
44
What pathogens are commonly found in post operative endophthalmitis and what are the sources
s. epidermidis
flora of lids/ conjunctiva. Contamination via incisions in early post op stage. Contaminated solutions and instruments, environmental air, surgeon, other operating room personnel
45
What are the prophylactic steps to minimise endophthalmitis risk
instil 5% povidone into conjunctival fornices for 3 minutes preop
prep surgical site and redrape eyelashes away from surgical field
treat blepharitis/ conjunctivitis/chronic dacryocystitis/ infection in contralateral eye or socket preop
IC Cefuroxime at the end of surgery/Moxifloxacin
Early resuturing of leaking wounds rather than observe
46
What are some documented risks of intracameral vancomycin
haemorrhagic occlusive retinal vasculitis - avoid as routine prophylaxis
47
What is TASS and how is it managed
use of inappropriate or contaminated irrigating fluid or viscoelastic. An intense fibrinous reaction with corneal oedema may develop although other signs of infectious endophthalmitis are absent. Treatment is with intensive topical steroids and a cycloplegic.
48
What volume of aqueous is needed in tap
0.1-0.2mls on 25g needle
49
What volume of vitreous is needed in tap
1-2ml syringe to aspirate 0.2-0.4mls vitreous fluid and 23G needle or disposable vitrector.
50
What antibiotics and doses are used in endophthalmitis
Ceftazidime 2mg in 0.1ml and Vancomycin 2mg in 0.1ml
Amikacin 0.4mg in 0.1ml alternative to ceftazidime in penicillin allergic patients
51
What does the EVS study show
benefit for immediate PPV in eyes with LP vision at presentation with 50% reduction in severe visual loss.
52
What is the prognostic outcome for endophthalmitis
Eyes at LP vision presentation- 30% achieve 6/12 or better
If better than LP figure increase to 60%.
Poor outcome related to early retinopathy from exotoxins
53
What are some late problems with endophthalmitis
persistent vitreous opacification- aggressive extended topical, periocular, oral steroid leads to resolution. PPV considered if persistent opacification
Maculopathy- ERM/ CMO / Ischaemia
Hypotony- drain choroidal effusion, seal leaky wounds, RD/ anteiror vitreous membranes need vitrectomy
Chronic uveitis/secondary glaucoma/ RD/ phthisis
54
What is the pathogenesis of delayed onset endophthalmitis
develops when an organism of low virulence p. acnes becomes trapped within the capsular bag (saccular endophthalmitis). Organisms become sequestered within macrophages protected from eradication but continued expression of bacterial antigen. Occurs from 4 weeks to years (mean 9 months)
55
What are some signs of delayed onset endophthalmitis
low grade AAU, medium large KP's. Vitritis common. Inflammation responds but recurs once treatment stopped. Enlarging capsular plaque of organisms in residual cortex within the peripheral capsular bag is common
56
How to manage delayed onset endophthalmitis
fluoroquinolones topical -penetrate eye well, concentrated within macrophages.
57
How to treat delayed onset endophthalmitis
Intravitreal abx are alone unsuccessful
Removal of capsular bag/ residual cortex/ IOL requiring PPV + IVT abx (vancomycin)
Secondary IOL implantation considered at later date
58
How can the incidence of PCO be reduced
when capsulorhexis opening is in complete contact with anterior surface of the IOL.
59
What types of IOLs are more prone to PCO
PMMA and probably hydrophilic to a lesser extent. Implant design is more relevant. Square optic inhibit PCO but high rate of dysphotopsia
60
What is a Soemmering ring
whitish annular or doughnut shaped proliferation of residual cells classically formed in the periphery of capsular bag following older methods of cataract surgery. May form at the edge of capsulorhexis or capsulotomy
61
What size opening should you aim for in YAG PCO
Equate approximately to the size of physiologically dilated pupil under scotopic conditions- average 4-5mm in pseudophakes.
Should not extend beyond optic edge as vitreous can come round it and prolapse forward
62
What is capsular bag distension syndrome
fluid accumulates between IOL and posterior capsule leading to distension of posterior capsule, slight anterior displacement of IOL and myopic shift. Trapped fluid becomes turbid causing reduced vision.
63
What are the risk factors for capsule distension syndrome
AL >25mm
small capsulorhexis
adhesion between IOL optic and anterior capsular rim
64
What test can confirm diagnosis of capsule distension syndrome and how is it treated
Anterior segment OCT
YAG PC
65
What are the risk factors for post operative CMO
ERM
History of CMO in fellow eye
PC rupture + vitreous loss and incarceration into incision site
AC IOL
Secondary IOL
Diabetes (10x risk)
Uveitis
Topical prostaglandin treatment
66
What is the difference between negative and positive dysphotopsia
A dark shadow in the temporal periphery (negative dysphotopsia – often the most troublesome), scintillations,
haloes, peripheral or central glaring or flashes (positive dys-
photopsia) and possibly monocular diplopia.
67
How to manage dysphotopsias post cataract surgery
- reassure patient symptoms settle with time- neuroadaptation
- positive nocturnal symptoms with pupil constriction eg brimonidine but dilation can help with negative dysphotopsia
- reverse optic capture (vaulting optic forward out of the bag, leave haptics in place), sulcus IOL, Piggyback IOL in sulcus
- IOL exchange to round edged lens
Avoid laser capsuolotomy as it complicates exchange
68
What are some reasons for post phaco ptosis
use of post op topical steroids. Do not correct until at least 1 year post op
69
What is the incidence of congenital cataract and how common is bilaterality and what is the inheritance pattern
3 in 10,000 live births.
2/3rd bilateral
AD inheritance
70
What are some causes of congenital cataracts
chromosomal abnormalities, metabolic disorders, intrauterine infections
71
What is the pathogenesis of Galactosaemia and what sort of cataract is typical
AR condition
Impairment of galactose utilisation caused by absent galactose 1 phosphate uridyl transferase (GALT). Unless galactose is withheld from diet, severe systemic complications result in death. Oil droplet lens opacity develops within first few days/ weeks of life.
72
What is the pathogenesis of Lowe syndrome and what sort of cataract is typical
oculocerebro renal syndrome is X linked recessive OCRL 1 gene. Inborn error of amino acid metabolism with neuromuscular renal and other manifestations. Cataract universal and microphakia also present. Congenital glaucoma in 50% of patients.
73
What is the pathogenesis of Mannosidosis and what sort of cataract is typical
AR disorder
Deficiency of alpha mannosidase. Progressive mental deterioration/ MSK. Punctate lens opacities arranged in spoke like pattern in posterior lens cortex frequent. Corneal clouding can occur
74
What intrauterine infections are associated with congeital cataract
Rubella
Toxoplasmosis
CMV
Varicella
Measles
Syphilis
HSV/ HIV
75
What are some systemic and ocular features of down syndrome
LD, stunted growth, distinct facial and peripheral features, thyroid dysfunction. Cataract- opacities varied and symmetrical develop in late childhood. Iris Brushfield spots, hypoplasia, chronic blepharitis, myopia, strabismus and keratoconus
76
What are some systemic and ocular features of Edwards syndrome (Trisomy 18)
facial/ peripheral features, deafness, cardiac anomalies, LD, early death
Ocular- cataract, ptosis, microphthalmos, corneal opacity, uveal and disc coloboma, VR dysplasia
77
What are some associations of anterior polar cataract
PPM, Aniridia, peters anomaly, anterior lenticonus
78
What are some associations of posterior polar cataract
posterior lenticonus
fetal vascular remnants including Mittendorf dot. This form of opacity high risk for dehiscence during surgery and PCR
79
What should be kept in mind when thinking about operating on congenital cataracts
balance the fact that the earlier you operate especially <4 weeks age high risk of glaucoma in juvenile years
80
When should bilateral dense congenital cataracts be operated on
between 4-10 weeks of age to prevent stimulus deprivation amblyopia
81
When should bilateral partial congeital cataracts be operated on
may not require surgery until later. Defer surgery in favour of monitoring
82
When should unilateral dense congenital cataracts be operated on
more urgent surgery. No consensus. 6 weeks latest point at which surgery performed. generally between 4-6 weeks. Followed by aggressive anti amblyopia therapy.
83
At how many weeks is the prognosis for congenital cataract poor
if detected after 16 weeks of age
84
What surgical points are important to address during this congenital cataract surgery
anterior capsulorhexis
aspiration of lens matter
capsulorhexis of posterior capsule
limited anterior vitrectomy + IOL implantation
85
What are some post operative complications after congenital cataract surgery
PCO- universal MUST do posterior surgical capsulotomy at primary operation
Secondary membranes if uveitis not treated aggressively
Proliferation of lens epithelium universal forming Soemmering ring- inconsequential
Glaucoma- younger age of surgery higher risk. Secondary OAG in 20% eyes before 5 years after surgery. Angle closure immediately post op in microphthalmic eyes
RD uncommon quite late complication
86
What does post congenital cataract surgery visual rehabilitation look like
spectacles for older children with bilateral aphakia
Contact lenses- for bilateral/unilateral aphakia. After 2 years compliance may worsen
IOL implantation in younger children effective- aim hypermetropia, as eye grows becomes emmetropic/ myopic
87
What is ectopia lentis
hereditary or acquired displacement of lens fromn normal position
Lens may be completely dislocated making it aphakic or partially displaced. Manifest with phacodonesis.
87
What are some acquired causes of ectopia lentis
Trauma
PXF
Inflammation: chronic cyclitis, syphilis
Hypermature cataract
Large eye eg high myopia/ buphthalmos
88
What are some causes of ectopia lentis without systemic associations
Familial ectopia lentis - AD condition bilateral symmetrical superotemporal displacement
Ectopia lentis et pupillae rare congeital bilateral disorder. AR inheritance displacement of pupil and lens in opposite directions. Pupils small dilate poorly. Microspherophakia may be present
Aniridia
89
What are some causes of ectopia lentis with systemic associations
Marfan syndrome
Weill Marchesani syndrome
Homocystinuria
Sulfite Oxidase deficiency
Stickler syndrome
Ehler Danlos Syndrome
hyperlysinemia
90
What are some features of Marfan Syndrome
AD inheritance FBN1 gene variable expressivity. MSK features tall thin stature/ arachnodactyly, narrow high arched palate. Dilation of aortic root, mitral valve prolapse, aortic aneurysm formation
Bilateral ectopia lentis 80%, subluxation superotemporal. Zonules intact. Glaucoma/ RD/ lattice degeneration seen
91
What are some features of Weill Marchesani syndrome
Rare systemic CTD. Converse of Marfans. Inheritance AR/ AD.
AD results from polymorphism in FBN1 gene. Short stature short fingers, LD, Ectopia lentis 50%. Inferior subluxation in late childhood, microspherophakia so pupil block with angle closure can happen
92
What are some features of Homocystinuria
AR disorder- decreased enzymatic metabolism of amino acid methionine causes systemic accumulation of methionine and homocysteine
Features are coarse blond hair, blur iris, malar flush, marfanoid habitus, neurodevelopmental delay, early atherosclerosis
Treat with oral pyridoxinem folic acid, vitamin B12 to reduce plasma homocysteine and methionine levels.
Ectopia lentis is inferonasal universal by 25 years. Zonules have high cysteine levels disintegrate so accommodation lost. Pupil block occurs. Other eye features iris/ optic atrophy, myopia, RD
93
What is anterior lenticonus
bilateral axial projection of anterior lens surface int oAC. oil droplet sign seen on retroillumination. Almost all patients have Alport syndrome.
94
What is Alport syndrome
ereditary condition characterized by pro-
gressive sensorineural deafness and renal disease associated with
abnormal glomerular basement membrane. Retinal
flecks and posterior polymorphous corneal dystrophy may also occur.
95
What is posterior lenticonus
Bulging of the posterior axial lens associated with local thining/absence of posterior capsule. Most unilateral, sporadic. With age bulging increases and lens cortex may opacity. Posterior subcapsular opacification is common.
96
What is lentiglobus
rare, unilateral generalized hemi spherical deformity of lens. Associated with posterior polar opacity
97
What is Microspherophakia and Microphakia
Microspherophakia- lens small and spherical
Microphakia- small lens than normal diameter
98
Conditions associated with Microspherophakia
isolated familial (dominant) abnormality, or in association with a number of systemic conditions
Marfan and Weill–Marchesani syndromes, hyperlysinaemia and congenital rubella.
Ocular associations include Peters anomaly and familial ectopia lentis et pupillae.
99
What is a lens coloboma
congenital indentation of lens periphery. Result of localised zonular deficiency. Not a true coloboma as no focal absence of tissue layer due to failure of closure of optic fissure. Occasionally lens coloboma associated with iris/fundus coloboma
100
Part 2
flashcards
Decks in class (20)
# Cards
-
Exam Techniques68
-
Eyelids183
-
Lacrimal Drainage System41
-
Orbit167
-
Dry Eye34
-
Conjunctiva80
-
Cornea183
-
Corneal and Refractive Surgery49
-
Episclera and Sclera35
-
Lens101
-
Glaucoma236
-
Uveitis191
-
Retinal Vascular Disease147
-
Acquired Macula Disorders163
-
Inherited Retinal Degenerations127
-
Retinal Detachment99
-
Vitreous Opacities10
-
Strabismus201
-
Neuro-ophthalmology352
-
Ocular Tumours164
