Does Age Influence the Effect of Povidone Iodine 5% on the Cornea?

Research Article

Austin J Clin Ophthalmol. 2017; 4(2): 1081.

Does Age Influence the Effect of Povidone Iodine 5% on the Cornea?

Ridder III WH¹*, Oquindo C¹, Dhamdhere K² and Burke J²

¹Southern California College of Optometry, Marshall B. Ketchum University, Fullerton, CA 92831, USA

²Allergan, Inc., 2525 Dupont Dr. Irvine, CA 92623, USA

*Corresponding author: Ridder III WH, Southern California College of Optometry, Marshall B. Ketchum University, 2575 Yorba Linda Blvd, Fullerton, CA USA 92831, USA

Received: July 19, 2017; Accepted: August 10, 2017; Published: August 17, 2017


Purpose: To determine if age influences the effects of 5% Betadine applied to the eye on visual function, corneal integrity and subjective complaints.

Methods: Twenty subjects were chosen to participate in this study (Ten younger: 25.8 +/- 2.94; and ten older: 58.2 +/- 5.59). LogMAR acuity, contrast sensitivity, corneal fluorescein staining, and subjective complaints were measured before and after 60μl of 5% Betadine was applied to one eye (baseline, 5, 30, and 60 minutes and 4 and 24 hours post-application). Contrast sensitivity at 14cpd was determined with a spatial two-alternative, forced choice procedure (BeethovenTM software). The NEI grid pattern was used to grade corneal staining with sodium fluorescein. Subjective complaints were monitored using the Schein dry eye questionnaire.

Results: The data were analyzed with an ANOVA (linear mixed-effects model). For all the subjects, logMAR acuity was significantly reduced from baseline at the 30 and 60 minute visits (all p values < 0.05) and contrast sensitivity was reduced from baseline at 5, 30, and 60 minutes after Betadine application (all p values < 0.0001). Total corneal staining and the Schein dry eye questionnaire were significantly different from baseline at every visit (all p values < 0.05). The age groups were only different at the 1 hour visit for logMAR acuities.

Conclusions: 5% Betadine application significantly decreases epithelial integrity of the cornea, decreases functional vision, and increases subjective complaints. Age has a minimal effect on the result.

Keywords: Betadine; Corneal staining; Vision; Contrast sensitivity; Symptoms


A recently published study demonstrated that the application of povidone iodine 5% (brand name Betadine 5%, Alcon Laboratories, Inc., Fort Worth, TX) to the eyes of normal patients resulted in an increase in corneal staining and subjective complaints that lasted 24 hours and a loss in functional vision lasting 1 hour [1]. Povidone iodine 5% is commonly used pre-operatively to disinfect the ocular surface [2-5]. In these procedures, a few drops of povidone iodine are placed in the conjunctival sac and this significantly decreases the local bacterial concentration [6]. With the large increase in the number of intravitreal injections in the last decade (i.e., from about 3000 in 1999 to over 2 million in 2012 [7]) ocular disinfection has become extremely important [8,9].

Previous studies of povidone iodine 5% have not considered the effect of the patients age on the cornea or vision [1]. Since aging results in several changes in the cornea (e.g., increased epithelial cell permeability, impaired wound healing, decreased number of keratocytes, decreased endothelial cell density), povidone iodine 5% may be more toxic to the corneas of older patients [10,11]. The effect of age may also be significant because most patients undergoing intraocular injections or surgery are older. The mean age for patients undergoing cataract surgery is over 70 [12,13]. Thus, older individuals may exhibit a greater extent of corneal staining and functional vision problems than younger individuals in response to povidone iodine use.

Povidone iodine can reduce visual function either by disrupting the tear layer or producing corneal epithelial cell damage. The administration of any fluid (e.g., an artificial tear) to the ocular surface can disrupt the tear layer and interfere with vision [14-16]. Tear layer disruption results in a decrease in the modulation transfer function (MTF) for the eye [17,18]. The tear layer is the first refracting surface of the eye and its break up can cause a decrease in contrast sensitivity and visual acuity [19-21]. Artificial tears should have the least effect on visual function. Other agents, like povidone iodine, are not designed to replace or supplement the tear layer. Thus, povidone iodine may not mix well with the native tear layer and can significantly alter visual function due to tear layer disruption. This effect may be greater in older individuals since they are more likely to have an unstable tear layer and a dry eye [22].

Povidone iodine is more acidic than the tear layer and the free iodine it releases may cause corneal epithelial cell damage [23]. Applying Povidone iodine to the conjunctival sac of humans and rabbits produced severe epithelial damage [1,24]. The epithelial damage can then further disrupt the tear layer. If this occurs over the optic axis, this would interfere with vision. Thus, vision can be affected either by the application of povidone iodine disrupting the tear layer or the resulting corneal epithelial cell damage. Age related changes in the cornea may exacerbate the effects of povidone iodine. In this study, the effect of age on povidone iodine 5% use in the normal eye was determined.



Twenty subjects free from ocular pathology were chosen (age range 22 – 68, average age ± SD = 42.0 ± 17.2). The subjects were divided into 2 age groups of 10 each: younger (age range 22 – 33, average age 25.8 ± 2.94) and older (age range 52 – 68, average age 58.2 ± 5.59). Subjects were recruited from the College community. Informed consent was obtained from all subjects after the testing procedure was explained to them and the procedures adhered to the tenets of the Declaration of Helsinki [25]. The procedures were approved by Sterling IRB (Atlanta, Georgia). The subjects were seen for an eligibility visit to determine if they met the inclusion and exclusion criteria.

Inclusion criteria

There were no requirements as to subject race, gender or occupation. All subjects met the following criteria:

Test procedures

Table 1 gives the visit schedule and the tests performed (i.e., visual acuity, contrast sensitivity, sodium fluorescein staining of the cornea, Schein questionnaire) at each visit.