Study type
Study method
Suite A
Suite B
Retrospective comparative
Phase 1. n = 10,608
Jan 1988–Mar 1989
Preoperative conjunctival topical application of Argyrol (n = 4547)
Preoperative conjunctival topical application of Argyrol (n = 6101)
Prospective comparative
Phase 2. n = 8083
Apr 1989–Feb 1990
Preoperative conjunctival topical application of 5% povidone-iodine
(n = 3489)
Preoperative conjunctival topical application of Argyrol
(n = 4594)
Argyrol is an antiseptic solution at varying strengths of mild silver protein. It is manufactured in the chemical industry to pharmaceutical grade using denatured pharmaceutical-grade protein for ophthalmic application and elemental silver to produce the silver protein molecule. It is recommended for use on mucous membranes to resolve local infections in mucous-membrane-lined organs. Historically, it has been extensively used in gonorrheal infections and in prevention of gonorrheal blindness.
Povidone-iodine (PI) is an antiseptic used for skin disinfection of patients and hands of the healthcare providers. PI came to commercial use in 1955, and it is on the World Health Organization (WHO) list of essential medicines. It has minimal toxicity but produces a powerful antimicrobial effect after 1 min of skin contact. This effect is attributed to the release of free iodine and persists for at least 1 h. It is believed that iodine penetrates the cell wall and reacts with amino acids and nucleotides, which, ultimately, disrupt the cell’s protein synthesis. It is contraindicated in people with iodine allergy and in people with hyperthyroid disease.
Results (Table 34.2)
There were 44 incidences of endophthalmitis in phase 1 study and 29 incidences of endophthalmitis in phase 2 study; culture-proven endophthalmitis occurred in 18 patients in phase 1 and in 13 patients in phase 2 study. There was statistically significant reduction of endophthalmitis with preoperative conjunctival application of 5% PI.
Table 34.2
Povidone-iodine prophylaxis study results
Study type | Study method | |
|---|---|---|
Suite A | Suite B | |
Retrospective comparative Phase 1. n = 10,608 | Topical Argyrol Total: 0.42% (19/4507) Culture +ve: 0.18% (8/4507) Culture −ve: 0.24% (11/4507) | Topical Argyrol Total: 0.40% (25/6101) Culture +ve: 0.16% (10/6101) Culture –ve: 0.25% (15/6101) |
Prospective comparative Phase 2. n = 8083 | Topical povidone-iodine Total: 0.11% (4/3489) Culture +ve: 0.06% (2/3489) Culture −ve: 0.06% (2/3489) | Topical Argyrol Total: 0.54% (25/4594) Culture +ve: 0.24% (11/4594) Culture –ve: 0.30% (14/4594) |
Recommendations
Povidone-iodine is recommended for both skin (10% solution) and conjunctival (5% solution) application. It is necessary that the contact time should be at least 1 min. Ideally, PI should dry after skin preparation and the conjunctival cul-de-sac should not be irrigated before 1-min contact time with PI solution.
Frequently Asked Questions
- 1.
What is the contact kill time of povidone-iodine?
A: The contact time varies from 10 to 900 s (15 min), but most of the microorganisms get killed in 60 s or less (Table 34.3).
- 2.
What is ideal povidone-iodine for ophthalmic care?
Microorganism | Contact kill time in seconds |
|---|---|
Staphylococcus | 15–80 |
Streptococcus | 15–30 |
Bacillus | 10–30 |
Nocardia | 60 |
Pseudomonas | 15–900 |
Escherichia | 30–120 |
Enterobacter | 60 |
Proteus | 15–180 |
Klebsiella | 60 |
Aspergillus | 30 |
Candida | 10–20 |
A: Wu et al. studied the impact of preoperative preparation protocol using different concentrations of PI in extracapsular cataract extraction (ECCE) with polymethylmethacrylate (PMMA) intraocular lens (IOL) insertion [2]. The protocols were:
Protocol 1—skin preparation with 10% PI + conjunctival preparation with 5% PI
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