3.1.8 Uses a slit lamp to assess anterior chamber signs of ocular inflammation.

Question 1

What does inflammation do to the eye?

Answer 1

• Causes dilated vessels, more WBCs come to protect against infection
  
  • The inflammatory response increases the amount of blood flow to the site of injury to get more nutrients and white blood cells to an area in need. To increase blood flow to the area, the blood vessels get wider (dilate).

Question 2

What is uveitis?

Answer 2

Inflammation of the uvea, the iris, ciliary boyd (focuses eye and produces clear fluid) and choroid (nourishes oter layers of retina). Inflammation of uvea is called uveitis, when this inflammation affects the iris and ciliary body, its called anterior uveitis - the most common type.

Question 3

How does it present?

Answer 3

• Symptoms - rapid onset of unilateral pain, blurred vision (depends on severity), photophobia, redness & watery discharge
• Signs - Ciliary Injection, Miosis, Cells & flare, KPs, Hypopyon, Iris nodules (Busacca - iris stroma, Koeppe - pupillary margin), PS, Lowered IOP (function of ciliary body not as good) (can sometimes be raised if TM blocked by cells & flare)
• Management - Emergency, same day referral. Make sure to look at fundus to exclude posterior uveitis & if clear view not obtained, must make HES aware

Question 4

Examination of uveitis

Answer 4

• Room lights OFF, time given for examiner to dark adapt
• Conical beam/something very close (3mm works) e.g. a slit set at the lowest height i.e. slightly higher than a conical beam
• Direct the microscope through pupil with light source at 45-60 degrees temporally, not illuminating any iris.
• Direct microscope onto aqueous by moving into focus (between beam on cornea & beam on lens), magnification 16-25X, highest brightness
• Move in & out; the aqueous should be optically empty and contain no cells or protein to give rise to aqueous flare (Tyndall’s phenomenon). Flare indicates recent or active inflammation and needs to be referred urgently
  
  • The fluid within the anterior chamber is called the aqueous humor. It is normally transparent akin to water, and lets through all the light from the front of the eye, so it can pass through the lens to fall on the retina.
  • However, when there are proteins present inside the fluid, the light may reflect in multiple directions, leading to the scattering of light. This is called the Tyndall effect, and is due to the presence of turbidity in the aqueous humor.

Question 5

Flare

Answer 5

protein in inflammation from break down of blood-aqueous barrier (limits diffusion of large molecules into aqueous & backflow of aqueous humour), escaping from dilated vessels (dilated from inflammation) of the ciliary stroma (part of ciliary body), into iris stroma & then into anterior chamber; smokey appearance, genuinely literally looks like black, whispy smoke floating in the aqueous

Question 6

Cells

Answer 6

white (in anterior uveitis) or red blood cells (red normally means hyphema e.g. after blunt trauma, intraocular surgery etc); can be counted. The white cells leak from inside the blood vessels of the uvea to outside the blood vessels. These white cells permeate the uveal tissue and leak out of the uvea into the aqueous

Question 7

Why should cells/flare be checked pre-dilation?

Answer 7

Should be checked before dilation, otherwise pigment cells can be released from dilation (rubbing of posterior iris to lens zonules). Also, NaFl in applanation tonometry can result in increased flare

Question 8

Sun grading scale:

Answer 8

Aqueous cells:
0. None
1. 2-5 cells seen in 45 seconds or one minute
2. 5-10cells seen at once
3. Cells scattered o

Question 9

Corneal Endothelium:

Answer 9

Specular Reflection
1. Focus on tear film 16x, angle 45 deg
2. Move microscope until dazzlling bright reflection seen
3. 3. Behind bright reflection there should be duller reflection; endothelium, increase mag to 40x

Question 10

Iris & Lens anterior surface

Answer 10

• Retroillumination works best
  
  • Use 1.5-2mm beam, height reduced & directed straight on (0-10 degrees) into pupil to show red reflex

Question 11

Conical beam must be used to check the aqueous for cells & flare:

Answer 11

o Makes beam width & height equal (1mm) to produce circular light
o 45 degrees
o Turn off room lighting.
o Oscillate joystick. May get px to look up and then straight. Medium to high mag.
o Beam if focused between the cornea and anterior les

Question 12

Sun Grading scale, AC Cells

Answer 12

SUN Grading AC Cells
0 <1
0.5+ 1 – 5
1+ 6 – 15
2+ 16 – 25
3+ 26 – 50
4+ 50+

Question 13

Sun grading AC flare

Answer 13

SUN Grading AC Flare
0. none

1. faint
2. moderate (iris/lens still visible)
3. marked (iris/lens hazy)
4. intense (fibrin/plastic aqueous)

Question 14

Different types of uveitis

Answer 14

 The uvea is comprised of the iris, ciliary body & posterior choroid
 Iritis = inflammation of the iris (anterior uveitis)
 Iridocyclitis = inflammation of iris and ciliary body
 Intermediate: inflammation of pars plana, peripheral retina, vitreous
 Posterior: inflammation posterior to vitreous base
 Panuveitis: inflammation of the entire uveal tract (iris, ciliary body and choroid) – always chronic

Question 15

Acute

Answer 15

Single episode (25% patients)
Non-granulomatous
 Acute onset
 Fine KPs
Generally idiopathic
Usually unilateral

Question 16

Chronic

Answer 16

> 3 episodes (40%)
Granulomatous
 Mutton fat KPs
 Iris nodules
More likely to be associated with systemic conditions
 RA, IBS etc
If bilateral – more likely to become chronic
Eye may be asymptomatic despite presence of inflammation

Question 17

Symptoms

Answer 17

 Sudden onset (at first episode), more gradual at subsequent
 Reduced vision likely (if unilateral, may be reduced vision between each eye)
 Pain – exacerbated by induced pupillary constriction
 Photophobia
 Redness
 Lacrimation

Question 18

(sorry!)

Signs

Answer 18

 Circumcorneal hyperaemia (ciliary injection)
 Pupil - miosis due to sphincter spasm or misshaped due to posterior synechiae
 Aqueous cells (WBCs)
 Aqueous flare – haziness of the aqueous in the AC (protein)
 Keratic precipities (corneal endothelial deposits; formed by aggregation of polymorphonuclear cells, lymphocytes and epithelioid cells) – more common in chronic/longstanding
o Adhere to the corneal endothelium sclerotic scatter on the cornea or indirect parallelepiped
o Mutton fat – large cluster present (granulomatous)
o Fine – small (non-granulomatous)
 Hypopyon – horizontal level of whitish purulent exudate composed of inflammatory cells @ inferior AC
 Posterior synechiae – occurs at the pupil margin; iris is adherent to the anterior lens
o If substantial – pupil block - affect aqueous movement from the posterior to anterior chamber
o This causes the iris bombe / iris bows forward
 IOP affected
o Decreased in acute phase due to decreased aqueous production
o High due to posterior synechiae causing iris bombe or viral conditions such as HSV
 Iris nodules (uncommon)
o Koeppe – small & near pupil
o Bussaca – large & far from pupil
 Anterior vitreous cells indicate intermediate & posterior uveitis
 Posterior segment check to rule out CMO & posterior uveitis

Question 19

Differential diagnosis

Answer 19

 AACG (hazy cornea, nausea)
 Intraocular FB (DIY history)
 Other forms of uveitis

Question 20

Management (CMGs)

Answer 20

 Non-pharmacological - sunglasses for photophobia & cyclopentolate to ease symptoms
 Local guidelines (G&GC) – emergency referral to ophthalmology, generally phone ARC
o Generally given prednisolone 1% hourly until eye white – penetrating steroid
o 2 hours for 5 days; and then begin tapering over no less than 6 weeks
o Cyclopentolate 1% tds 7 days ciliary spasm & prevent synechiae
 Generally, IP can treat in practice, more likely to refer if 1st episode / signs of granulomatous inflammation