Confocal imaging in a fungal invasion of contact lenses.

A 53 year old gentleman presented with complains of decreased vision and discomfort in his left eye (LE) on wearing his contact lenses. His current pair of contact lenses (CLs) were 6 months old and he was an experienced polyhydroxyethylmethacrylate (PHEMA) CL user. Best distance visual acuity in both eyes was 20/20. In the LE, a whitish patch was noted on the CL, which had a granular appearance with fuzzy borders [Fig. 1]. After removing the CLs, corneal superficial punctate keratopathy was noted on fluorescein staining in both eyes (BE) and the rest of the ocular examination was unremarkable. The CL was mounted on a lens holder and confocal microscopy was performed [Fig. 2], which revealed long filamentous branching structures on the surface of CL with short filaments within the substance of the CL [Fig. 3a]. These findings were suggestive of fungal invasion of the CLs, and it was confirmed by histopathological examination using hematoxylin–eosin (H&E) [Fig. 3b] and Grocott–Gomori methenamine silver staining. The patient was storing the lenses in Bausch and Lomb Renu multiplus lens solution dispensed to him with CLs. The microbiology culture of CLs and solution grew Fusarium species. He was asked to discontinue lenses for 2 weeks and order a new pair of CLs. The patient was doing fine until the last follow-up.

Figure 1

(a) Diffuse illumination of a slit-lamp photograph of the left eye with contact lens on showing granular whitish opacity with fuzzy borders (inset) (b) Diffuse slit-lamp photograph of the left eye showing clear cornea after removal of the contact lens

Figure 2

Performing the confocal microscopy of a contact lens after mounting it on a lens holder. (a) Gross image of the infected CL (b) Loading the CL onto the CL holder (c) Applying gel over the CL before confocal microscopy () Performing the confocal microscopy

Figure 3

(a) Negative confocal scan image showing small fungal fragments within the substance of contact lens. (b) Hematoxylin–eosin stain image of the contact lens showing fungus growing in a filamentous form on the surface of the contact lens and the form of penetration pegs (black arrow) within the substance of the contact lens

Discussion

The incidence of fungal contamination of CLs is believed to be around 2% to 5%.[1] It is believed to occur more commonly in hydrophilic CLs and with surface irregularities on the CL.[2] The fungus grows in filamentous form on the surface of CL while it grows in short corkscrew pattern within the substance of the CL, penetration pegs.[34] More than 250 cases have been reported worldwide which have been primarily associated with multipurpose CL disinfecting solutions.[5] Confocal microscopy in such cases can be a helpful noninvasive tool to arrive at the diagnosis.

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Conflicts of interest

There are no conflicts of interest.