Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

*BCSC deck > Lens > Flashcards

Lens Flashcards

1
Q

What type of cataract is characteristic of ischemic ocular conditions?

A

Posterior subcapsular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Chronic UV radiation exposure typically causes what type of cataract?

A

Cortical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the most radiosensitive structures in the eye?

A

Lens > cornea > retina > optic nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How much radiation exposure leads to cataract formation? How long does it take to develop cataracts after radiation?

A

2 Gy in 1 fraction, 2-3 years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What lens capsule finding is seen when operating on patients with aniridia?

A

Thinner than normal lens capsule -> makes capsulorrhexis challenging

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is responsible for postoperative myopic shift?

A

Capsular contraction or phimosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What complication is more common after intracapsular CEIOL than extracapsular?

A

Retinal detachment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is posterior infusion syndrome or posterior fluid misdirection syndrome?

A

Occurs after hydrodissection -> fluid misdirected into vitreous cavity leading to anterior displacement of lens and shallowing of anterior chamber

Not associated with pain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What types of IOLs have been associated with highest rates of corneal decompensation?

A

Closed-loop ACIOLs, iris-clip lenses

Flexible/open-loop ACIOLs at less risk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What can be done to reduce increased risks of cataract surgery in patient with COPD?

A

Small-incision surgery: reduces risk of suprachoroidal hemorrhage and iris prolapse

Reverse Trendelenburg position may help patient breathe more easily

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

After performing LASIK in myopic patient, how will central corneal power differ when measured by keratometer versus topography?

A

Corneal curvature is overestimated by keratometry compared to topography (keratometry only measures central 3 mm)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What IOL is most likely to cause negative dysphotopsia?

A

Smaller square-edge PCIOL in the bag

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What IOL pathology is associated with positive dysphotopsias?

A

Decentered PCIOLs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What carbohydrate metabolism change occurs in lens in presence of high levels of glucose?

A

Aldose reductase activity increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the rate-limiting step in glucose phosphorylation in the lens? What occurs when glucose concentration increases in the lens?

A

Hexokinase reaction

Sorbitol pathway activated when glucose concentration increases -> aldose reductase is key enzyme in this pathway

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What kind of patient would benefit from Trendelenburg positioning for cataract surgery?

A

Kyphotic patients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What should be done during cataract surgery for eye containing silicone oil?

A

Inferior iridotomy to prevent pupillary block from silicone oil migration into anterior chamber through zonules

18
Q

What should be done for nanophthalmic eyes undergoing cataract surgery to reduce risk of uveal effusion? (3)

A

Suture all incisions, administer mannitol preoperatively to dehydrate the vitreous, use lower aspiration rate or higher infusion pressure

19
Q

When performing phacoemulsification on patient with zonular incompetence, what change in settings would most effectively reduce chances of complications?

A

Lower aspiration flow rate -> diminishes fluctuation and turbulence in AC depth, reduces risk of vitreous prolapse

20
Q

What average IOP-lowering effect is expected from phacoemulsification in eye with high IOP?

A

10-30% IOP lowering (can consider cataract surgery as stand-alone procedure in eyes with early to moderate glaucoma)

21
Q

What is viscosity of OVDs? What factors determine viscosity?

A

Resistance to flow, thickness and thinness of a fluid

Determined by molecular weight and concentration

22
Q

What is elasticity of OVDs?

A

Ability to return to original tape after being stressed

23
Q

What is surface tension of OVDs?

A

How readily fluid sticks to another surface

Inversely proportional to coatability: low surface tension is better at coating tissue, but more difficult to remove from the eye

24
Q

What pattern of Nd:YAG laser reduces risk of lens dislocation?

A

Spiraling circle

25
Q

What type of cataract develops as a result of blunt trauma?

A

Stellate or rosette cataract involving posterior lens capsule

26
Q

Anesthesia of terminal branches of facial nerve

A

van Lint block

27
Q

Anesthesia of CN VII trunk as it exits stylomastoid foramen between mastoid process and mandibular ramus

A

Nadbath-Ellis block

28
Q

Anesthesia of CN VII anterior to tragus at mandible

A

O’Brien block

29
Q

Anesthesia of temporofacial branch along inferior border of zygoma toward top of ear

A

Atkinson block

30
Q

What complications result from inadvertent intravenous injection of retrobulbar anesthesia?

A

Cardiac arrhythmia, seizures, respiratory arrest, brainstem anesthesia

31
Q

What is most commonly isolated from cultures of patients with cataract surgery-associated endophthalmitis?

A

Staph epidermidis

32
Q

What complication is associated with reverse “S-shaped” insertion of aspheric single-piece IOL?

A

Loss of asphericity and refractive surprise (small myopic shift)

33
Q

What is the most common enzyme deficiency that causes galactosemia?

A

Galactose 1-phosphate uridyltransferase (Gal-1-PUT)

34
Q

What is a benefit of retrobulbar over peribulbar anesthesia?

A

More rapid anesthesia

35
Q

The majority of high-energy phosphate bonds for lens metabolism are provided by what pathway?

A

Anaerobic glycolysis

36
Q

What percentage of lens glucose passes through citric acid cycle?

A

3%

37
Q

What leads to age-related nuclear sclerosis?

A

Formation of protein-to-protein and protein-to-glutathione disulfide bonds (aggregation and accumulation of insoluble proteins)

38
Q

What is a risk factor for intraoperative iridodialysis?

A

Floppy iris syndrome

39
Q

What clinical test tests macular function in patient with dense cataract precluding visualization of fundus?

A

Maddox rod testing (loss of red line of Maddox glass = scotoma suggesting macular disease)

40
Q

Where is the germinative zone of the lens epithelium?

A

Immediately anterior to the equator

41
Q

Risk factors for suprachoroidal hemorrhage (7)

A

Hypotony, high myopia, age, hypertension, tachycardia, cardiovascular disease, longer operating times

42
Q

Minimum visual acuity threshold for PAM to accurately estimate potential vision

A

> 20/200

Macular issues (AMD, edema, scarring), serous RD, glaucoma, amblyopia can make PAM testing unreliable

*BCSC deck (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions