Deposit buildup on prosthetic eyes and implications for conjunctival inflammation and mucoid discharge - Beryl Carvalho - Eyes Alive

Introduction

Pine et al have used recently developed measuring tools1 to demonstrate that the presence of surface deposits on prosthetic eyes is associated with less conjunctival inflammation and less severe mucoid discharge in anophthalmic sockets.2 However, the causal direction of these associations was not established in this study. Furthermore, there appears to be no literature describing deposit buildup on prosthetic eyes, even though extensive literature describes deposit buildup on contact lenses. Prosthetic eyes are somewhat analogous to contact lenses, but are made from different materials and worn for very different reasons. Both devices come into contact with the conjunctiva, share a similar eyelid action, are bathed in the same ocular fluids, and accumulate surface deposits. Because of these similarities, relevant information from contact lens investigations provides a useful background for this study.

For example, the composition of deposits on contact lenses is likely to be similar to deposits on prosthetic eyes. Contact lens deposits include tear proteins, lipids (lipid deposit buildup may be both on the surface and inside the lens matrix3,4), mucin, and contaminants, such as skin lipids, dirt, micro-organisms, and metallic and nonmetallic debris.

The aims of this investigation were: to describe the formation of surface deposits on prosthetic eyes over time; to investigate rates of deposit buildup on prostheses with different standards of polish; and to understand the cause of the reported associations between deposits, conjunctival inflammation, and severity of mucoid discharge.1

Materials and methods

Forty-three unilateral prosthetic eye wearers were entered into the study after they completed a questionnaire and agreed to participate in prosthetic eye research which had prior approval from the University of Auckland Human Participants Ethics Committee and the Multi-Region Ethics Committee of the New Zealand Ministry of Health. Participants were excluded from the study if they were aged younger than 18 years, had ocular health issues, or had not worn a prosthetic eye for at least 6 months.

Measuring surface deposits on prosthetic eyes

A staining solution was made by dispersing 5 g of plaque disclosing gel (a mix of mainly ethyl alcohol, food red 105, and water; GC Corporation, Tokyo, Japan) in 30 mL of 0.85% saline solution.1 The participants’ prostheses were submerged in the solution at 20°C (68°F) for a period of 2 minutes. After removing and blotting with tissue paper, the prosthetic eyes were photographed front and back against a black background which included a standard gray scale and a color scale to ensure the consistency of photographic settings throughout the study. Standardized camera settings were used.2 Photographs of the stained prostheses were coded to deidentify the participant but to allow tracking. Each photograph was copied onto the center of a Microsoft PowerPoint (Microsoft Corporation, Redmond, WA) slide which contained a previously developed 0–10 photographic grading scale by which the extent and intensity of deposit buildup could be measured.1 Separate anterior surface and posterior surface deposit scales allowed assessment of the severity of deposit buildup according to the extent and intensity of the stained deposits. The graders were the authors (an experienced ophthalmologist, optometrist, and ocular prosthetist) who used interpolated grades to the nearest 0.1 between 0 and 10 when assessing the deposits. The final grade for the stained deposits on each prosthetic eye was the average of the three graders’ anterior surface and posterior surface scores.