[Transient visual decrease after photodynamic therapy].

BACKGROUND

After photodynamic therapy (PDT) some patients complain about a transient decrease of visual acuity during the first postoperative week.

PATIENTS AND

METHODS

Prior to and at 2 days and 1 week after PDT the following parameters were measured: (1) best corrected visual acuity (VA), (2) changes in refraction, and (3) A scan ultrasound biometry was carried out. Linear and 3-D optical coherence tomography was performed in three cases. A total of 53 PDT treatments were followed-up in 24 patients.

RESULTS

Comparison of the pre- and postoperative refraction demonstrated a mean hyperopic shift of +0.35 diopters (dpt) in 43% of treatments (23/53) on the second postoperative day. The hyperopic shift reduced to +0.07 dpt after 1 week. The best corrected VA remained stable or was even better in 68% (36/53) on the second postoperative day. A decrease in VA could be noticed in 32% (17/53) at this time which declined to 23% (12/53) after 1 week. Measurement of the cornea-retina distance using A-scan ultrasound biometry disclosed a mean axial reduction of 0,13 mm at the second postoperative day. This correlates closely with an average hyperopic shift of 0,35 dpt. OCT examination disclosed a transient macular edema in the treated retinal areas.

CONCLUSIONS

A transient hyperopic shift can be measured in 43% on the second postoperative day. The subjective decrease in visual acuity measured over the postoperative days was mainly due to a transient hyperopic shift in our patients. OCT findings disclosed a transient macular edema of the retina treated with PDT, which may relate to a hyperopic shift.