Вторник, 02.03.2021, 05:19
Вітаю Вас Гость | Реєстрація | Вхід

і

Архив статей

Головна » Файли » 2013 » 3 (117)

Жабоедов Д.Г., Чиж И.Г. Экспериментальное исследование аберраций интраокулярных линз при их децентрации
25.07.2014, 16:24

Резюме
Жабоедов Д.Г.1, Чиж И.Г.2 Экспериментальное исследование аберраций интраокулярных линз при их децентрации.
Представлено экспериментальное исследование аберраций различных моделей интраокулярных линз при их децентрации на искусственной модели глаза. Анализ полученных данных выявил, что линза SL-907 обладает меньшей чувствительностью к децентрации по сравнению с другими моделями ИОЛ.
Ключевые слова: катаракта, факоэмульсификация, интраокулярная линза, децентрация, индуцирование аберраций.
Резюме
Жабоєдов Д.Г., Чиж І.Г. Експериментальне дослідження аберацій інтраокулярних лінз при їх децентрації.
Представлено експериментальне дослідження аберацій різних моделей інтраокулярних лінз при їх децентрації на штучній моделі ока. Аналіз отриманих даних виявив, що лінза SL-907 має меншу чутливість до децентрації порівняно з іншими моделями ІОЛ.
Ключові слова: катаракта, факоемульсифікація, інтраокулярна лінза, децентрація, індукування аберацій.
Summary
Zhaboedov D.G., Chyzh I.H. Aberration experimental study of intraocular lenses at its decentration.
It has been presented the experimental study of aberration induction of IOL different models at its decentration on the artificial eye model. Analysis of the data revealed that the IOL SL-907 has a lower sensitivity to decentration compare to other models.
Key words: cataract, phacoemulsification, intraocular lens, decentration, aberration induction.
Рецензент: д.мед.н., проф. А.М. Петруня

УДК 681.7.066:535.317.6

1Национальный медицинский университет им. А.А. Богомольца (Киев)

 O.O. Bogomolets National medical university (Kyiv)

2Национальный технический университет Украины «Киевский политехнический институт»

National Technical University of Ukraine "Kyiv Polytechnic Institute"

 

zhaboedov@ukr.net

The method of intraocular correction of aphakia has now gained world-wide recognition as the most important stage in medical and vocational rehabilitation of patients with cataract. One of the significant conditions for high optical results achieving is the intracapsular implantation of intraocular lens (IOL) with its maximal centering. However, violations of the IOL central position relative to the optical axis of the eye from the slight shift and decentration to subluxation and complete dislocation are known to occur even at perfectly performed operations, leveling the optical and structural advantages of modern IOLs [1, 4, 8, 10].

According to various authors, the frequency of IOL decentration varies widely – from 10 to 92% [1, 3, 6, 9, 11]. Consequently, IOL implanting in the capsular bag of removed crystalline lens can’t guarantee an exact match of its optical axis with the optical axis of the cornea. So the lens optical axis may be parallel to the cornea optical axis i.e. decentring laterally along the horizontal (axis OX), vertical (axis OY) or simultaneously along both these axes. IOL angular rotation (tilt) around one of the axis is another possible manifestation of decentration.

IOL decentration not only changes the attitude position of optical axis but also leads to marked increase in the aberrational mode amplitude of all degrees especially the lower ones, that have a significant impact on the patients’ visual functions and respectively their quality of life. In this regard, the study of the features of decentred IOL aberration properties is an important task that is essential, both theoretical and practical, since at the presence of a IOL model variety it is still an open question its optimal choice which is depended on individual characteristics of an eye and operation course [2, 5, 7, 8, 11]. Obtaining of objective data on the sensitivity of different IOL models to decentration which generate aberrations is an important factor at the final selection of the lens model for implantation.

The purpose of the study is to identify the changes in spectrum of aberration modes of different models of IOL caused by its decentration.

Materials and methods

The experimental model of the eye has been developed and manufactured at the Department optical and optoelectronic devices of National Technical University of Ukraine «Kyiv Polytechnic Institute» (NTUU «KPI») led by professor I.H. Chyzh.

Aberrometry has been conducted by the ray-tracing aberrometer TRACEY-VFA (USA, Tracey Technologies) with inserting of an IOL inside the physical model of an eye optical system. By means of special gears of IOL shifting along the horizontal axis OX and the angular rotation of IOL around vertical axis the lateral decentration within ±1 mm and rotary decentration within ±8 degrees have been set.

Results

At first aberrometry of the eye model has been conducted without an IOL. The eye model was placed on the aberrometer and centered relative to the optical axis of the aberrometer by mirror images of centering infrared LEDs, produced by light reflection from front surface of the lens-cornea. Then investigated IOL was placed inside of the model and centered regarding to position of centering LEDs mirror images. The average value of the every aberration mode amplitude of the eye model without an IOL, found on the 10 sessions, was subtracted from the average value of the same aberration mode amplitude of the model with a centered IOL. Difference of values, obtained by means of statistical methods, indicated the value of the aberration mode amplitude brought into the model by the IOL itself.

IOL decentration relative to the axial light beams coming out of the lens-cornea, caused changes of the IOL aberration mode amplitudes. These changes were identified by comparing two average values of each aberration mode amplitude, one of which was obtained from the series of 10 sessions of aberrometry of the model with a decentered IOL, and the second – from the series of 10 sessions of aberrometry of the model with a centered IOL. Similarly it was defined the changes of IOL aberration mode amplitudes due to IOL rotation around the vertical axis.

IOL decentration along the axis OX was set to the value ±0.5 mm and ±1 mm, values of IOL angular rotation around the vertical axis were ±4° and ±8°. Aberrometry data of IOL centered relative to cornea are shown in the table 1.

Table 1

Aberrometry data of IOL centered relative to lens-cornea

Manufacturer

IOL

Focal Power

[D]

Lower RMS

[µm]

Higher RMS

[µm]

Total RMS

[µm]

Abbott Medical Optics Inc., USA

TECNIS®

20

0,116

0,139

0,181

Alcon Laboratories Inc., USA

SA60AT

21

0,137

0,053

0,147

SN60WF

20

0,240

0,077

0,252

«US Optics», Ukraine (by technology Lenstec Inc., USA)

SL-907

20

0,044

0,044

0,062

RMS mean value of the IOLs

0,201

0,110

0,236

RMS variation range of the IOLs

max

0,389

0,202

0,403

min

0,044

0,044

0,062

 

               

 

Analysis of the aberration mode spectrum of IOL SL-907 shows that small values of its RMS are the result of much smaller amplitudes of its aberration modes. In our opinion this shows clearly higher quality of this model manufacturing.

Table 2 shows the ranges of IOL decentration and angular rotation which do not lead to RMST values exceeding 0,05 µm (by Marechal) and 0.1 µm (RMS conditionally acceptable value). It is obvious that IOL SL-907 has widest tolerance due to lower sensitivity to decentration and rotation (tilt), slightly lower – IOLs TECNIS® and SN60WF. The IOL model SA60AT shows he lowest tolerance.

 

Table 2

Valid values of IOL decentration and rotation

IOL

Р [D]

Valid value

(RMST=0,05 µm)

Valid value

(RMST=0,1 µm)

Decentration [mm]

Rotation [degree]

Decentration [mm]

Rotation [degree]

TECNIS®

20

±0,30

±2

±0,45

±2,7

SN60WF

20

±0,19

±1,5

±0,30

±2,5

SA60AT

20

±0,1

±0,8

±0,15

±1,2

SL-907

20

±0,3

±3

±0,6

±4,5

 

Conclusions

  1. Thus IOL decentration in the range ±1 mm and angle rotation of ±8° cause an increase of aberration mode amplitudes that accordingly leads to a substantial increase of the RMS values far more exceeding the limit set by Marechal.
  2. Equal values of IOL decentration cause different changes in aberration values of different IOL models, and there is a correlation between RMS proper values and increment of RMS depending on IOL decentration. Lenses with high proper aberrations have significantly higher values of RMS increments caused by IOL decentration.
  3. IOL SL-907 has widest tolerance due to lower sensitivity to its decentration and rotation (tilt), slightly lower – IOLs TECNIS® and SN60WF. The IOL model SA60AT shows he lowest tolerance.

Литература

  1. Алиев Э.Г. Особенности зрительных функций и хирургческой реабилитации у пациентов при децентрации интраокулярных линз с внутрикапсульной фиксацией: дис. … канд. мед. наук : спец. 14.00.08 «Глазные болезни» / Эльман Гасанбала оглы; ФГУ МНТК «Микрохирургия глаза» им. акад. С.Н. Федорова. – М., 2005. – 151 с.
  2. Биометрия положения интраокулярных линз на основе Шаймпфлуг-фотографии / Е.Н. Батьков, Н.П. Паштаев, Н.А. Поздеева, В.В. Зотов // Современные технологии катарактальной и рефракционной хирургии: сб. науч. ст. – М., 2009. – С. 37–42.
  3. Варавка А.А. Аберрометрия при дислокации ИОЛ / А.А. Варавка, А.Б. Качанов // Современные технологии катарактальной и рефракционной хирургии: сб. науч. статей. – М., 2011. – С. 64–68.
  4. Стебнев С.Д. Дислокация интраокулярных линз. Причины, характер, хирургическая тактика, результаты лечения / С.Д. Стебнев, В.М. Малов // Современные технологии хирургии катаракты: сб. науч. ст. – М., 2007. – С. 237–243.
  5. Altmann G.E. Optical performance of 3 intraocular lens designs in the presence of decentration / G.E. Altmann, L.D. Nichamin, S.S. Lane, J.S. Pepose // J. Cataract Refract Surg. – 2005. – Vol. 31. – P. 574–585.
  6. Baumeister M. Tilt and decentration of spherical and aspherical intraocular lenses: effect on higher-order aberrations / M. Baumeister, T. Kohnen // J. Cataract Refract. Surg. – 2009. – Vol. 35, № 6. – P. 1006–1012.
  7. Castro A. Tilt and decentration of intraocular lenses in vivo from Purkinje and Scheimpflug imaging / A. Castro, P. Rosales, S. Marcos // J. Cataract Refract. Surg. – 2007. – Vol. 33, № 3. – P. 418-429.
  8. Hayashi K. Intraocular lens tilt and decentration after implantation in eyes with glaucoma / K. Hayashi, H. Hayashi, F. Nakao // J. Cataract Refract. Surg. – 1999. – Vol. 25, № 11. – P. 1515–1520.
  9. Kim J. Biometry of types of intraocular lenses using Scheimpflug photography / J. Kim, K. Shyn // J. Cataract Refract. Surg. – 2001. – Vol. 27, № 4. – P. 533–536.
  10. Phillips P. Measurement of intraocular lens decentration and tilt in vivo / P. Phillips, J. Perez-Emmanuelli, H. Rosskothen // J. Cataract Refract. Surg. – 1988. – Vol. 14. – P. 129–135.
  11. Taketani F. Influence of intraocular lens tilt and decentration on wavefront aberrations / F. Taketani, T. Matuura, E. Yukawa [et al.] // J. Cataract Refract Surg. – 2004. – Vol. 30 (10). – P. 2158 – 2162.
Категорія: 3 (117) | Додав: siderman | Теги: phacoemulsification, интраокулярная линза, факоэмульсификация, decentration, aberration induction, intraocular lens, cataract, катаракта
Переглядів: 487 | Завантажень: 0 | Рейтинг: 0.0/0
Всього коментарів: 0
Додавати коментарі можуть лише зареєстровані користувачі.
[ Реєстрація | Вхід ]
RSS

Форма входу

Категорії розділу

1 (115) [43]2 (116) [45]
3 (117) [41]4 (118) [34]
5 (119) [47]6 (120) [38]

ПОИСК

НАШ ОПРОС

Оцените наш сайт
Всего ответов: 46

ДРУЗЬЯ САЙТА

Статистика


Онлайн всего: 1
Гостей: 1
Пользователей: 0