Abstract
Purpose :
The Boston keratoprosthesis (KPro) is used for the treatment of corneal blindness in cases of poor prognosis for traditional keratoplasty, with favorable visual outcomes and improvement in quality of life. However, patients implanted with this device often complain of disabling glare under certain conditions and it is unknown how visual function differs from that of a normal cornea. The purpose of this study is to evaluate intraocular light scattering and color vision in patients implanted with KPro.
Methods :
Patients with implanted KPro and vision better than 20/100 were asked to participate in the study. Eyes were divided into PMMA and titanium backplate groups. When possible, the patient’s fellow eye served as control. Intraocular scattering was quantified with a C-Quant (OCULUS Optikgeräte GmbH) straylight meter that measures foveal light scatter (log S) produced by a glaring light ring at 7 degrees of eccentricity. Color vision was assessed with the use of Munsell D-15 test.
Results :
Fifteen eyes implanted with Boston type 1 keratoprosthesis (10 with PMMA backplate and 5 with titanium backplate) were measured. Eight eyes (5 eyes without corneal pathology, 1 eye with mild aniridic keatopathy and 2 eyes with keratoconus and no corneal opacity) served as controls. We found that PMMA KPro backplate model produced more intraocular light scattering than the control cornea (p<0.01). There was also a trend towards more light scattering in the PMMA group compared to the titanium group but this did not reach significance for the sample size (p = 0.11). There was no difference in color vision testing among groups, probably due to the long-term chromatic adaptation.
Conclusions :
Eyes implanted with Boston KPro have significantly more intraocular light scatter than fellow eyes with a normal and/or diseased cornea. An opaque backplate such as the titanium model may contribute to reduce intraocular light scattering in these patients.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.