3.1.2 Uses a slit lamp to examine the external eye and related structures.

Question 1

Illumination style: Direct

Slit lamp settings for: Lashes, Bulbar conj, Palpebral conj

Answer 1

• Low (6-10x)
• Filter: No
• Slit size: wide
  Looking for:
• Lashes: Blepharitis/styes
• Bulbar conj: Hyperaemia/pterygium/pinguecula
• Palpebral conjunctiva: Hyperaemia/Follicles/Papillae

Question 2

Illumination style: Direct

Slit lamp settings for: Lid margins, contact lens

Answer 2

• Med/high (16-25x)
• Filter: No
• Slit size: wide
  Looking for:
• Lid margins: Meibomian glands/tear duct patency
• contact lens: Lens fit

Question 3

Illumination style: Direct

Slit lamp settings for: Cornea, iris, lens surface

Answer 3

• Med/high (16-25x)
• Filter: No
• Slit size: Medium
  Looking for:
• Cornea: Opacities
• iris: Naevus
• lens surface: Qualitiy/wetting/engravings

Question 4

Illumination style: Direct

Slit lamp settings for: Limbus

Answer 4

• Med/high (16-25x)
• Filter: Red-free
• Slit size: Medium
  Looking for:
• Limbus: Vascularisation

Question 5

Illumination style: Direct

Slit lamp settings for: Cornea (DEEP)

Answer 5

• Med (25-40x)
• Filter: No
• Slit size: Narrow
  Looking for:
• Limbus: Dellen/stroae/folds/endothelial

Question 6

Illumination style: Direct

Slit lamp settings for: Cornea, Conjunctiva

Fluro

Answer 6

• Med/high (16-25x)
• Filter: Blue + Fluroscein
• Slit size: Medium
  Looking for:
• Cornea: Staining
• Conjunctiva: Staining

Question 7

Red-free filter

Answer 7

• Blocks structures below retional pigmental epithelium (RPE) and enhances contrast of retinal blood vessels and haemorrhages
• Helps in cup to disc (C:D) ratio assessmemt
• Helps identify nerve fibre layer (NFL) dropout - a sign of glaucoma

Question 8

Blue filter

Answer 8

• Can enhance reflectivity of optic disc drusen
• For use with fluorescein/fluorescrein angiography
  *

Question 9

Yellow filter

Answer 9

Reduces UV exposure

Question 10

Common techniques for slit lamp:

Answer 10

• Decoupling a slit lamp allows free movement of illumination to allow for sclerotic scatter. Good for corneal opacities, corneal clouding, band keratopathy etc
• Specular reflection for endothelium viewing
• Neovascularisation seen using retroillumination & even green illumination
• Conical beam for cells & flare
• Iris & lens transillumination

Question 11

Step by Step approach: anterior exam

Answer 11

• Wash hands or use hand sanitiser
• Set up patient at correct height, with canthus marker aligned. Always ask if height is okay for the patient
• Get patient to look at your right ear if starting with right eye & vice versa
• Start with lids & lashes. Scan across bottom then top lids with 6-10X mag, ideally bright diffuser beam
• Then conjunctiva & sclera with 10X mag. Make patient look left, then up, then right, then down (lift lid!) then straight at your ear
• Use 16X mag for cornea & lens with parallelepiped & working your way into optic section. This is when you do your van hericks nasal & temporal
• Use retroillumination on the lens by aligning the illumination & microscope at 0 degrees ,directed at the pupil then more towards the edge of the pupil and you will see an orange reflex

Question 12

Van Hericks & Angles

Answer 12

• Assessor will ask you to do van hericks then ask you to grade it. So make sure you know where 60 degrees is! Nasal & temporal!
• It is worth learning about van hericks & angle closure glaucoma:
  
  • Grade 1 <1:4, grade 2 1:4, grade 3 1:2 grade 4 1:1 or 1:1>
    
    • Read College Management guidelines
• Risk of angle closure is after dilation is 0.07-0.09%?

Question 13

Angle closure suspect:

Answer 13

• Description: Anatomically pre-disposed eye
• Symptoms: None
• Signs: high IOP, narrow angles (grade 1-2), schaeffer grade 1 or less
• Management: Laser iridotomy

Question 14

Intermittent angle closure

Answer 14

• Description: Recurrent attacks lasting 1-2hrs
• Symptoms: Transient blurred vision/haloes, headaches
• Signs: High IOP & corneal swelling during attacks, narrow/occludable angles in between attacks
• Management: Laser iridotomy

Question 15

Acute angle closure

Answer 15

• Description: total closure, sudden & painful
• Symptoms: Severe pain, nausea, blurred vision/haloes
• Signs: Redness, closed angles, corneal oedema, vertically fixed mid dilated pupil, very high IOP
• Management: Emergency referral. Oral acetazolamide if IOP 40+. Laser irodomy, miotics & carbonic anhydrase inhibitors used

Question 16

Chronic angle closure

Answer 16

• Description: Progressive closure due to synechiae
• Symptoms: None (at first)
• Signs: Peripheral anterior synechiae on gonioscopy, disc changes (pallor), Hlaucomfleckem iris atrophy, dilated pupil
• Management: Laser iridotomy

Question 17

Peripheral anterior synechiae and Glaucomflecken?

Answer 17

Peripheral anterior synechiae —> adhesions of anterior iris to TM blocking the iridocorneal angle

Glaucomflecken —> looks like “spilled milk” on the anterior lens capsule - from necrosis of lens epithelial cells

Question 18

Prediposing Factors for Angle Closure

Answer 18

Anatomical

sex (F:M ratio 3:1)
ethnicity (e.g. Chinese, Vietnamese, Inuit). PACG is recognized as a leading cause of blindness in East Asia
family history
short axial length (hypermetropia)
shallow AC (F>M)
increasing age (AC becomes shallower as lens thickness increases)
small corneal diameter
Iatrogenic (secondary angle closure) - i.e. caused by medication or treatment

Drug induced (topical and systemic)
Adrenergic agents e.g. phenylephrine

Drugs with anticholinergic effects e.g. tricyclic antidepressants, antihistamines

Drugs that may cause ciliary body oedema, e.g. topiramate (for epilepsy and migraine), sulphonamides

Surgery induced
Angle closure may follow a number of surgical procedures, for example vitreo-retinal surgery with intraocular gas, especially in aphakic eyes

Question 19

Treatment for acute angle closure glaucoma

And extra information

Answer 19

• Medication - acetazolamide, anti hypertensives
• Interventions - YAG laser treatment/iridotomy, clear lens/cataract removal

Extra Information

• Pupillary block —> angle between lens & posterior iris closed off
• Non pupillary block (plateau iris) —> iris bows forward to block angle between iris & posterior cornea