Abstract
Purpose::
To evaluate the changes of binocular functions such as convergence, divergence, AC/A ration, and near point of convergence(NPC) after the artisan phakic IOL implantation, performed on high myopes.
Methods::
Before the surgery, examinations related to binocular functions were performed. Using rotary prism, convergence and divergence amplitude was measured. Distant and near target were told to focus, by rotating the rotary prism at a constant speed in front of an eye with and without glasses, break and recovery point were measured. For an AC/A ratio, the lens gradient method was used. After the IOL implantation followed by a manufacturer's protocol, the examinations before the surgery were repeated at 1 week, 1 month, and 3 months after surgery. The statistical significance was defined as if p value < 0.05.
Results::
21 myopes enrolled the study. Mean refractive error was -9.43 1.14 diopter(D) and mean age was 27.0 ± 3.3 years old, ranging 23 to 34. After the IOL implantation, mean refractive error was -0.43 ± 0.39 D at 3 month after the surgery. Convergence and divergence break point were 23.04 ± 3.11 PD and 14.20 ± 3.42 PD before the surgery and had decreased after the surgery without any statistical significance. Recovery point showed a similar result. AC/A ratio was 6.39 Δ/D before the surgery, but had decreased to 5.12 Δ/D and 4.79 Δ/D at 1 month and 3 months after surgery respectively, which were statistically significant. NPC showed no statistical significant changes after the surgery.
Conclusions::
There were no statistically signifant changes of binocular visual function, specifically convergence and divergence, after the phakic IOL implantation, but had showed a pattern of decrease. In the other hand, AC/A ratio decreased with statistical significance after the surgery. Thorough pre- operational evaluation of binocular function would prevent an unexpected complication related with the phakic IOL. And also, the results would provide a clue to the safety of phakic IOL implantation.
Keywords: binocular vision/stereopsis • vergence • refractive surgery: phakic IOL