Solution Confusion Causes Corneal Edema: A Case Report

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Cameron Clark
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1 Solution Confusion Causes Corneal Edema: A Case Report Elizabeth Dow, O.D. Cornea/Contact Lens Resident The University of Alabama at Birmingham, Birmingham, Alabama, USA Abstract A 47- year- old female presenting with complaints of sudden- onset blurry vision following wear of soft contact lenses soaked in gas permeable contact lens solution is diagnosed with bilateral toxic keratitis and corneal edema. I. Case History a. Patient demographics: 47- year- old African American female b. Chief complaint: The patient reported sudden- onset blurry vision after inserting soft contact lenses (Acuvue Oasys for Presbyopia) that she had accidently soaked in rigid gas permeable (RGP) contact lens solution (Optifree GP) for one night. c. Ocular history: This patient is a long time spectacle wearer and has worn RPG contact lenses for over ten years. When reaching presbyopia, she was refit into a soft multifocal contact lens at another office. She suffered a foreign body related corneal abrasion in 2006 which healed without lasting consequences. Her ocular history is also positive for strabismus surgery at age seven and vision therapy as a child; she remains an intermittent alternating exotrope. In addition she has been diagnosed with meibomian gland dysfunction and bilateral suspicion of glaucoma due to optic nerve head appearance (notch and cupping). d. Medical history: Her medical history includes hypertension, seasonal allergies and acid reflux. She was previously a smoker and currently occasionally drinks alcohol. e. Medications: Hydralazine/hydrochlorothiazide f. Other salient information: The patient presented with complaints of bilateral blurred vision one day following a bifocal RGP contact lens follow up appointment. As adjustments were being made to the segment height, prism and power of her bifocal RGP lenses, she returned to soft multifocal contact lens wear (Acuvue Oasys for Presbyopia). She mistakenly soaked her soft contact lenses in Optifree GP instead of Optifree RepleniSH overnight. She inserted her lenses upon waking and by the time she drove to work in the morning, her vision was blurry in both eyes. She attempted to clean the lenses of the Optifree GP solution with RepleniSH, but was unable to resolve her visual blur. The patient said her eyes burned a little bit but denied any pain. She presented to clinic wearing only the right soft contact lens. The soft multifocal contact lenses were fit at another office and the parameters are not known. II. Pertinent Findings a. Visual acuities 1. Entering visual acuities were OD 20/100 (c soft contact lens) and OS 20/200 (sc)

2. Corrected visual acuity in phoropter with most recent Rx dated three weeks prior was OD: - 4.00 DS, 20/80 +2, pinhole 20/70-2 and OS: - 3.75-0.50x120, 20/70, no improvement with pinhole b.

2 2. Corrected visual acuity in phoropter with most recent Rx dated three weeks prior was OD: DS, 20/80 +2, pinhole 20/70-2 and OS: x120, 20/70, no improvement with pinhole b. Biomicroscopy scattered superficial punctate keratitis (spk), OU 2. limbus to limbus corneal edema with stromal haze, OU stromal striations, OU 4. Anterior segment photos, OU (right eye, photo credit: Amber Zaunbrecher, OD) c. Intraocular pressure: Goldmann tonometry: 21mmHg OD, OS III. Differential Diagnosis a. Primary/leading 1. Toxic keratitis OU 2. Soft contact lens edema OU b. Others 1. Endothelial dystrophy OU 2. Inflammatory conditions (ex: infectious) OU

3 IV. Diagnosis and Discussion a. Diagnosis: bilateral toxic keratitis with corneal edema, suspect secondary to RGP solution used with soft contact lenses b. Discussion: 1. Clinical findings Stromal striations as seen in figure 1 occur when corneal thickness has increased by six to seven percent. (1) These white lines are apparent when edema in the stroma disrupts the regular configuration of the collagen fibers. (1) This type of reaction to preservative toxicity in ophthalmic preparations is not well documented and a broad literature review gleans little information and a lack of case reports. This patient also showed signs of epithelial damage as superficial punctate keratitis. Preservative toxicity to the corneal epithelial is a well- researched and publicized topic and not to be covered in this case presentation. 2. Investigation of etiology The patient in this case suffered an unusually adverse reaction to a contact lens solution. What is especially interesting is that this patient was habitually using Optifree GP as her RGP lens solution. It was not until she wore a soft contact lens that had been soaked in the GP solution that she had a toxic reaction. A soft contact lens extends the amount of time that an ophthalmic solution is in contact with the cornea. (2) Furthermore, soft contact lenses can absorb preservatives into their polymer matrix and serve as a reservoir, (2) whereas preservatives are less likely to be absorbed by rigid gas permeable contact lenses. (3) Hence, any adverse effects that the solution components have on the ocular tissues may be exacerbated. (2) An inquiry into the solution contents and possible causative agent is warranted in this case. Optifree GP solution contains: a cationic cellulose derivative polymer, hydroxypropyl guar, a proprietary wetting/conditioning polymer system, polyethyele glycol, Polyquad (polyquaternium- 1) % and edetate disodium 0.01%. Of these components, those that raise suspicion as causative toxic agents are the preservatives: edetate disodium and Polyquad. Polyquad is also present in this patient s habitual soft contact lens solution, Optifree RepleniSH. By this line of reasoning, edetate disodium is the remaining causative agent for this patient s toxic reaction. Edetate disodium has been found to cause less corneal toxicity than other preservatives (4). Nonetheless, all preservatives that are effective against bacterial growth are known to be toxic to the ocular surface. (3) As mentioned, soft contact lenses can absorb preservatives into their polymer matrix and serve as a reservoir. (2) When compared to preservative molecules of a larger molecular weight, a molecule with a smaller molecular weight is more likely to be absorbed into the lens material. Said preservatives would be of a moderately low molecular size, estimated by molecular weights (mw) on the order of 500 grams per mole (g/mol) and under. (3) The molecular weight of edetate disodium is 372 g/mol. (figure 2)

4 Figure 2. Edetate disodium (mw: 372 g/mol) (5) As such, edetate disodium could potentially be sequestered into the soft contact lens material during soaking only to later be released down the concentration gradient onto the ocular surface. This may lead to high concentrations of the preservative on the eye. (6) It has been shown that the toxicity of edetate disodium is dependent on the concentration and duration of exposure to human corneal epithelial cells, (7) both of which were increased in this case. V. Treatment, management The patient was reassured, educated on the nature of the condition and instructed to begin Muro 128 5% solution qid, OU and to begin Tobradex ophthalmic solution qid OU. She was also advised to discard her current soft contact lenses. Muro 128 was prescribed for its hypertonic effects of dehydrating the edematous corneas. Tobradex was prescribed to both provide antibiotic cover for the epithelial defects and curb the inflammatory reaction to toxicty. She did not have her glasses and was given one pair of Acuvue TruEye daily disposable contact lenses, /8.5/14.2 OU to be worn until she got home and then discarded. She was warned against driving and confirmed that her spouse would pick her up. She was instructed to return to clinic the following day. The patient returned the next day, as instructed. She had used Tobradex two times since the last visit but was unable to find Muro 128 at the pharmacy. The patient said that her eyes felt better and her vision was back to normal. Spectacle corrected visual acuities were 20/20 OD, 20/20 OS and 20/15 OU. Slit lamp exam reveals mild spk and clear, non- edematous stroma in both eyes. No striations were observed. The anterior chamber was deep and quiet. Intraocular pressure measured via Goldmann tonometry was 18 mmhg OD, OS. The patient was instructed to continue Tobradex qid x 4 days OU and not to wear her soft contact lenses x 4 days. Her next appointment would be scheduled when her RGP bifocal contact lenses arrived. VI. Conclusion This case was an unusually adverse reaction to a solution that this patient habitually uses for her RGP contact lenses. The use of the solution on a soft contact lens allowed a toxic level of preservative to remain on the ocular surface in both an extended duration and elevated concentration: the preservative was not only held on the eye upon insertion of the soft contact lens but also released from the lens matrix reservoir. The sustained contact time and concentration of the preservative on the cornea caused the toxic reaction observed. This patient has had many years of experience with both soft and hard contact lenses and is aware of proper care and solution use. Her adverse reaction occurred when she

5 mistakenly used Optifree GP instead of Optifree RepleniSH, as their appearance and labeling is similar (Figure 4). Figure 4: Optifree RepleniSH and Optifree GP The author suggests that it may perhaps be advantageous to patients for the appearance of solution packaging to be immediately discernible, especially in an uncorrected and potentially blurry state. This case of corneal toxicity was accidental on the part of the patient, but may have a clinical lesson to practitioners who prescribe piggyback style lens systems for corneal irregularities such as keratoconus. When two separate care systems are prescribed for the patient in a piggyback fitting system, there can be solution exchange once the lenses are on the eye. Using a care system that is compatible with both soft and RGP lenses can be considered. One example of such a system is Clear Care. This solution is approved for both soft and RGP contact lenses. Since Clear Care utilizes the neutralization of hydrogen peroxide into water and oxygen gas, the possibility to preservative toxicity is removed. VII. References 1. White, Paul. "Contact Lens Complications - - Part II." Contact Lens Spectrum Feb Web. 02 Aug Silbert, JA. A review of therapeutic agents and contact lens wear. Journal of the American Optometric Association (1996):

6 3. Than, Tammy. "Drop and Ointment Instillation in Contact Lens Wear." Review of Cornea and Contact Lenses 19 May Web. 02 Aug Kusano, Mao, Masafumi Uematsu, Takeshi Kumagami, Hitoshi Sasaki, and Takashi Kitaoka. "Evaluation of Acute Corneal Barrier Change Induced by Topically Applied Preservatives Using Corneal Transepithelial Electric Resistance In Vivo." Cornea (2010): "Edetate disodium." sigmaaldrich.com. Web. 24 Aug Chou, Brian. "Repairing Contact Lens Care." Contact Lens Spectrum Feb 2007: n. pag. Web. 02 Aug Saarinen- Savolainen, Paula, Tomi Järvinen, Kaoru Araki- Sasaki, Hitoshi Watanabe, and Arto Urtti. "Evaluation of Cytotoxicity of Various Ophthalmic Drugs, Eye Drop Excipients and Cyclodextrins in an Immortalized Human Corneal Epithelial Cell Line." Pharmaceutical Research (1998):

Case no.4. Subjective. Subjective (2) Caucasian female, 62 Y.O., consulting for a XXX opinion on her condition.

Case no.4. Subjective. Subjective (2) Caucasian female, 62 Y.O., consulting for a XXX opinion on her condition. Case no.4 Contact lenses: cause Subjective Caucasian female, 62 Y.O., consulting for a XXX opinion on her condition. Works as a lab technician for a veterenary surgeon No exposure to chemicals Had been