1. Re-emerging Acanthamoeba Keratitis (AK): Shift in diagnostic trends and outcomes Glasgow Experience
U Agraval, K Ramaesh, D Anijeet
Tennent institute of ophthalmology, Glasgow
 The authors have no financial interest to disclose

2. Purpose
Acanthamoeba keratitis (AK) appears to be re-emerging and remains a diagnostic challenge
INCIDENCE
1973: First Case of Acanthamoeba Keratitis
1989: US 1.36 per million contact len (CL) wearers
1999: Netherlands 3.06 per million CL wearers
1999: West of Scotland 149 per million CL wearers
2002: England/Wales 21 per million CL wearers
Diagnostic methods such as polymerase chain reaction (PCR) have made early diagnosis possible in high risk patients
We report the diagnosis, management and outcomes of patient with AK

3. methods
Retrospective study of 22 patients diagnosed with contact lens related AK at Gartnavel General Hospital, Glasgow
Between January 2009 to July 2014
DATA COLLECTION
Demographics
Delay in AK diagnosis
Type of contact lens
Diagnosis method
Signs and symptoms on presentation
Treatment
Visual outcome
Clinical features: early or late
Additional procedures
Initial visual acuity
Recurrence rate
Initial diagnosis
Follow up

4. NHS Glasgow And ClyDE: No. of cases
Results
NHS Glasgow And ClyDE: No. of cases
Left eyes: 13
Right eyes: 7
Bilateral: 2
22 patients: 7 M, 15 F
Age: mean 35.8, range 18-59
* No. of cases up to July 2014 – total of 17 cases of AK diagnosed in 2014

5. Results Signs and Symptoms Pain: 95% Photophobia: 763%
Foreign Body Sensation: 9%
Tearing: 9%
Decreased Corneal Sensation: 36%
Additional History
Poor hygiene: 2
Extended wear/ Slept in CL: 3
Use during swimming: 2
Type of Contact Lens
Rigid Gas Permeable: 9%
Soft monthly disposable: 40%
Soft daily disposable: 31% Cosmetic: 4%
Unknown: 14%

6. Additional Procedures - None
Results
EARLY FEATURES
Misdiagnosis
CL Related Keratitis: 75%
Corneal Abrasion: 8%
HSV Keratitis: 8%
Fungal: 8%
55%
Epitheliopathy
Punctate Keratopathy
Pseudo/True Dendrties
Perineural Infiltrates
Radial Keratopathy
Delay in Diagnosis
Range: 0-10 weeks
Mean: 2.5 weeks
Follow-up
Visual Acuity
Discharged: 25% 5-12 months
Local follow up: 16%
Range: 5-16 months
Initial: Range 6/6 to 6/36
Visual outcome: Range 6/5 to 6/12
6/5 – 6/6: 82%
6/9 - 6/12: 18%
25% still on treatment
Additional Procedures - None

7. Additional Procedures
Results
Misdiagnosis
Delay in Diagnosis
HSV Keratitis: 50%
CL Related Keratitis: 40%
Corneal Abrasion: 10%
Range: 2-16 weeks
Mean: 5.8 weeks
Additional Procedures
AMG: 50%
PK: 40%
Evisceration: 10%
Visual Acuity
Initial: Range 1/60-POL
Visual outcome: Range: 6/5 to HM
6/5-6/9: 30%
6/12-6/36: 30%
6/60 or less: 40%
30% still on treatment
LATE FEATURES
45%
Follow-up
Stromal infiltrates (Ring)
Ulceration
Anterior Uveitis
Discharged: 30% months
Range: months

8. Results Diagnosis METHOD
SHIFT: Corneal Scrape/Biopsy to Confocal/PCR/Diagnosis
: Early features: 15% Late features: 85% : Early features: 73% Late features: 27%

9. Results Treatment Duration of Treatment Early features:
Range: 1-11 months
Mean: 7 months
Ongoing treatment: 40%
Late features:
Range: 5-36 months
Mean: 14.6 months
Ongoing treatment: 30%
Biguanide – Polyhexamethylene biguanide (PHMB) 0.02% or Chlorhexidine 0.02%
Diamidine – Propamidine Isethionate (Brolene) 0.1% or Hexamidine 0.1%

10. High Index of Suspicion
conclusion
Early diagnosis of AK has a better visual prognosis, therefore early clinical features should be considered in CL wearers
Our study shows there is an emerging trend toward early diagnosis with the use of diagnostic methods such as PCR and confocal microscopy
As AK is re-emerging there should be a very low threshold to implement these in high risk patients
High Index of Suspicion
Contact Lens Wearers
Corneal Trauma
Exposure To Contaminated Water/Soil
Failure To Respond To First Line Treatment for Keratitis

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