An annular ring-tinted contact lens can be used to describe any colored contact lens that has pigment dispersed in a distinct circular pattern. For patients who suffer from certain ocular conditions, these lenses can greatly impact their quality of life.

Translucent Ring

When selecting the iris diameter, the eyecare practitioner is specifying the outer border of the ring tint. The ECP should select a size that is slightly larger than the measured horizontal visible iris diameter (HVID). In patients who have ocular cutaneous albinism (OCA), transillumination defects can result in severe photophobia in both indoor and outdoor lighting conditions.

A dark brown or black annular ring can be manufactured using a hydroxyethyl methacrylate (HEMA)-based lens. Children who have OCA can present with astigmatic refractive error, and a prism ballasted soft toric tinted custom lens can allow clearer vision and cut debilitating light sensitivity; no more wearing sunglasses indoors for these patients!

Opaque Ring

For conditions such as aniridia, traumatic aphakia, or a fixed and dilated pupil where photophobia, glare, monocular diplopia, and/or haloes are present, a tinted contact lens that allows some transmission of light may not suffice to alleviate the dysphotopsia. Most tinted annular rings can be made opaque by adding a black or white iris backing that allows for full iris occlusion (Figure 1).

Pupil Considerations

The conditions referenced above may not be the opportunity to measure the photopic and mesopic pupil size, and there can be varying levels of vision potential. Regardless of how limited the acuity can be, a clear pupil should always be considered. There may be no improvement in quantity of vision, but quality of vision gains is worth the effort in trialing different transparent pupil sizes.

While a pinhole can be trialed in office, a do-it-yourself pinhole tool can be used to better assess a pupil size that will improve any visually debilitating symptoms for a patient (Figure 2).

Finishing Touches

If the patient desires cosmesis enhancement in addition to symptomatic relief of unwanted visual disturbances, a computer-generated or hand-painted iris print added to the front surface of the lens can be used to match the non-effected eye or to bring iris color back to each eye.

This can mean layering several layers of pigment and can decrease oxygen to the corneal surface or even result in an annular tinted lens syndrome (Bucci et al, 1997), when the corneal surface irregularities develop at the clear pupil and pigmentary junction with long-term lens wear. Although the typical replacement schedule for such lenses is a minimum of 12 months, close follow-up with these patients biannually is needed to ensure the benefits of lens wear are not outweighing any risks. CLS

References

1. Bucci FA Jr, Evans RE, Moody KJ, Tanner JB, Capozza RC, Klyce SD. The Annular Tinted Contact Lens Syndrome Corneal Topographic Analysis of Ring-Shaped Irregular Astigmatism Caused by Annular Tinted Contact Lenses. CLAO Journal. 1997 Jul;23:161-167.