[Intraocular lens power in Russian population: distribution analysis]
S N Svetozarskiy1, A N Andreev1, A V Shvaikin1
1Volga District Medical Centre, Federal Medical and Biological Agency, Nizhny Novgorod, Russia.
Abstract:
Approximately 470 thousand cases of cataract surgery with implantation of intraocular lens (IOL) are performed annually in Russia. The distribution of IOL power in the Russian population has not been studied sufficiently, which makes the IOL procurement planning imperfect.
Purpose:
To analyze the distribution of implanted IOL power and optimize the IOL procurement system.
Material And Methods:
Retrospective analysis of cataract surgeries performed from 2014 to 2015 in the ophthalmic department of Volga District Medical Centre of the FMBA was conducted. Inclusion criteria: age from 20 to 99 years, no refractive surgery in patient's medical history, primary IOL implantation with an A-constant of 118.4, achievement of planned refraction. The studied parameters were IOL power, gender and age of patients. To assess the effectiveness of the procurement system, we analyzed the number of additional «unplanned» purchases and exchanges of IOLs over the course of 5 years (2014-2018).
Results:
According to the inclusion criteria, 1009 medical records were selected, the age of the patients was 68.7±10.9 years. The distribution of IOL power was similar, but different from the normal, characterized by the mismatch of the median and the mean, left-sided asymmetry and peaked shape. Comparison of 2014 and 2015 samples showed no significant differences and low variability of IOL power. Regression analysis revealed a weak correlation between the IOL power and age and no correlation with gender, a trend was observed for IOL power to increase in patients after 50 years. The use of a procurement planning system based on a mathematical model of the IOL power distribution allows reduction of the additional purchases and exchanges of IOLs with the supplier from 5-7% to 1-2% of the total purchases.
Conclusion:
The specific features of the IOL power distribution are related to the distribution of biometry parameters in the population. The use of a scientifically based procurement system reduces staff time and laboring costs, releasing economical and time resources.
