Background/aim: Little is known about biochemical markers related to change in visual acuity after vitrectomy. We investigated the potential use of transthyretin (TTR), a carrier of the retinol/retinol-binding protein, as a biochemical marker protein.
Methods: We measured TTR using immunonephelometry in a group of patients (n=77) in longstanding (> 1 week) retinal detachment (n=29), fresh (< 1 week) retinal detachment (n=17), macular holes (n=20), or diabetic retinopathy (n=11). Vitreous samples were taken at the start of every vitrectomy procedure. For reference values, cadaver specimens (n=73) were used.
Results: Reference values for vitreous TTR (median 18 mg/l; IQR 4-24 mg/l) comprised 2.2% of reference values for vitreous protein levels (median 538 mg/l; IQR 269-987 mg/l). Vitreous TTR values of patients were comparable in all disorders. Vitreous TTR values were higher in phakic (median 22.5 mg/l; IQR 10-27 mg/l) than in pseudophakic patients (median 12 mg/l; IQR 8-19 mg/l)(p=0.06). Postoperative change in visual acuity correlated well with vitreous TTR values found peroperatively (rs=0.408; p=0.012). Both change in visual acuity and lens status were the only variables which proved to explain the variance of TTR (multiple correlation coefficient: 0.494; phakic status: t=2.767; p=0.0084; and change in visual acuity t=2.924: p=0.0056).
Conclusion: Vitreous fluid concentrations of TTR can be regarded as a biochemical marker for retinal function.