Contact lens wear and diabetes mellitus

2024 Charles F. Prentice Medal award lecture: Moments of inspiration

In this Prentice Medal Award lecture, I shall recount my career in vision science in the context of three types of inspiration-"being inspired," "personal inspiration," and "inspiring others." My research has derived inspiration from a variety of sources, such as contemporary and historical research doyens in the ophthalmic field and beyond, artists, Greek philosophers, and abstract constructs such as principles and adages. A given moment of inspiration can range from being a profound experience to a subtle realization during a quiet moment of reflection. Here I shall recount the primary research domains of vision science that have defined my academic career in the context of the three types of inspiration defined above. These research domains are ophthalmic markers of diabetic neuropathy, ocular response to contact lens wear, contact lens-induced parainflammation, contact lens-associated microbial keratitis, grading scales for contact lens complications, contact lens prescribing surveys, material properties of contact lenses, contact lens compliance, history of contact lenses, ocular thermography, and ophthalmic bibliometrics. The notions of "being inspired" and "personal inspiration" are necessarily subjective, although I have endeavored to present them here in a scientific context. Conversely, the notion of "inspiring others" can be objectively gauged, at least in part, by counting article citations or the number of times articles are read online or downloaded from a journal website. In conclusion, my research in the vision sciences has been inspired by others, derived from personal ideas, and perhaps in turn has inspired others.

Contact lens wear and the diabetic corneal epithelium: A happy or disastrous marriage?

Diabetes mellitus is an epidemic in the US and abroad. With the advent of new contact lens technology, the use of contact lenses as glucose sensors in lieu of the traditional finger stick is quickly becoming realized. This has the potential to rapidly expand the contact lens market into this growing patient population. The independent cellular and physiological effects of contact lens wear and diabetes on the corneal epithelium have been described. However, little evidence exists to date to support whether there is increased risk associated with contact lens wear in diabetes. The focus of this review is to discuss what is known about the cellular effects of contact lenses on the corneal epithelium, the pathophysiological changes in the corneal epithelium that occur in diabetes, and whether an increased risk for corneal epithelial damage and/or infection may negatively impact safety in diabetic contact lens wearers. Available data indicates that there are inherent risks associated with contact lens wear in diabetics. Importantly, eye care practitioners fitting contact lenses in the diabetic patient need to carefully consider the duration of disease, the level of glycemic control, the presence of retinopathy, and the patient's overall health.

Tear film osmolarity in patients with diabetes mellitus

PURPOSE

To compare tear film osmolarity (TFO) between patients with diabetes mellitus (DM) and normal healthy individuals.

METHODS

In this prospective case-controlled study, the TFO in 46 normal subjects (control group) and 55 patients with DM (study group) was evaluated. TFO in milliosmole (mOsm) was measured by using an auto-osmometer. The serum levels of glycosylated hemoglobin (HbA1c) and blood glucose in all participants were also measured. Mean outcome measures were TFO and its relationship with HbA1c level and duration of DM.

RESULTS

Mean TFO was 320.40 ± 21.80 mOsm/l in the study group and 308.22 ± 18.16 mOsm/l in the control group (p < 0.001). The TFO values were significantly associated with duration of DM (r = 0.476, p < 0.001), but no significant correlation was found with HbA1c level (r = 0.225, p = 0.114).

CONCLUSIONS

The study shows a significantly higher TFO in patients with DM than in the healthy controls. TFO also correlates with the duration of DM.

Diabetes and contact lens wear

The literature suggests that diabetic patients may have altered tear chemistry and tear secretion as well as structural and functional changes to the corneal epithelium, endothelium and nerves. These factors, together with a reported increased incidence of corneal infection, suggest that diabetic patients may be particularly susceptible to developing ocular complications during contact lens wear. Reports of contact lens-induced complications in diabetic patients do exist, although a number of these reports concern patients with advanced diabetic eye disease using lenses on an extended wear basis. Over the past decade or so, there have been published studies documenting the response of the diabetic eye to more modern contact lens modalities. The results of these studies suggest that contact lenses can be a viable mode of refractive correction for diabetic patients. Furthermore, new research suggests that the measurement of tear glucose concentration could, in future, be used to monitor metabolic control non-invasively in diabetic patients. This could be carried out using contact lenses manufactured from hydrogel polymers embedded with glucose-sensing agents or nanoscale digital electronic technology. The purpose of this paper is to review the literature on the anterior ocular manifestations of diabetes, particularly that pertaining to contact lens wear.

Safety of contact lenses in patients with diabetes

The purpose of the present study was to determine if increased complications exist among patients with diabetes as compared with individuals without diabetes who wear soft disposable contact lenses for daily wear. Complications among daily-wear contact lens wearers who have worn soft contact lenses for 1 year or more were reported from a retrospective review of records. Eyes from 254 patients with diabetes and 254 individuals without diabetes (control), one eye for each subject, from six clinical practices were compared using chi2 and exact Wilcoxon analyses as appropriate. The overall incidence of complications was 49.8% among eyes of patients with diabetes and 48.0% among controls. The respective values for occurrence of corneal abrasions were 7.9% and 5.9%, those for corneal staining were 3.2% and 5.5%, and those for pain at some time while wearing a contact lens were 17% and 19.7%. No significant difference in complications, corneal abrasions, corneal staining, or experience of pain was found between daily-wear contact lens wearers with diabetes and controls. Thus patients with diabetes showed no increased complications over patients without diabetes for daily-wear soft contact lens wear.