This document discusses optical biometry measurements and their use in determining appropriate intraocular lens (IOL) calculations and selections. It provides an overview of biometry techniques such as ultrasound and optical methods, compares their accuracy advantages, and outlines considerations for different eye anatomies and conditions. Formulas for calculating IOL power are examined, including preferences for different eye lengths. Challenges in post-refractive surgery patients are also addressed.

1. Optical Biometry Measurements for Future IOL’s Aaron Graham, BA, CCOA

2. Financial Disclosure

3. Ground Rules

4. The Good Exclusive Эксклюзивные Exclusif Exclusiva Superior верхний Supérieur Superior Elite Элитные élite elisión Specialist Специалист Spécialiste Especialista

5. The Good

6. The Good

7. The Good

8. The Good

9. The Good

10. The Good

11. The Good

12. The Good

13. The Good

14. Good καλός Buono Versus έναντι Contro Bad κακός Cattivo

15. The Bad Indifferent Безразлично Indifférent Indiferente Inferior Нижняя Inférieur Inferior Generic родовой Générique Genérico Apathetic апатичный Apathique Apático

16. The Bad

17. The Bad

18. The Bad

19. The Bad

20. The Bad

21. The Bad

22. The Bad

23. The Bad

24. The Bad

27. However, it must be noted that the human eye itself has only a small spot of sharp vision in the middle of the retina, the fovea centralis, the rest of the field of view being blurry.

28. The angle of the sharp vision being just few degrees in the middle of the view, the sharp area thus barely achieves even a single mega pixel resolution.

30. "couching", in which a curved needle was used to push the lens into the rear of the eye and out of the field of vision. The eye would later be soaked with warm clarified butter and then bandaged.

31. Couching continued to be used throughout the Middle Ages and is still used in some parts of Africa and in Yemen.

32. 1748 First lens extraction (Modern Era)

33. 1884 First local anesthetics (Cocaine Drops)

34. 1940 First IOL (Harold Ridley)

35. 1960 PhacoemulsificationCataract Surgery Saga

37. Normal Measurements 23.5mm 12.5mm 245 μm 4.25 mm* 3.24 mm 0.5 – 8mm 550μm K: 43 - 44 D *LT is Age dependant andcontinuously growing

41. Immersion Method – The Immersion method of Ultrasound Biometry is by far the most accurate way to measure the AL of the eye using Sound. This method requires that the probe is placed in a “bath” of saline solution directly over the eye. With the immersion of the probe the cornea is not touched thus eliminating the compression errors.

46. IOL Master (Carl Zeiss)

47. OA 1000 (Tomey) to be launched 2000?Manufacturers

48. Optical Biometer Features

50. Multifocal / Accommodating IOL’s

51. Toric lenses

52. Patient specific anatomical anomalies

53. Very Long / Short Eyes / AstigmatismModern Technology / Knowledge

55. What about the “Dust Cover”?aka Cornea To ensure proper K value along central visual axis Keratometry should be measured at the same time as Axial Length.

56. Poor Alignment * Image courtesy of Karen Bachman and Cara Fletcher from the Cincinnati Eye Institute

57. 40.75 / 43.50 35.25 / 40.50 39.25 / 43.25 37.50 / 42.00 44.75 / 45.25 * Measurements obtained using Reichert Manual Keratometer Model # 12990

58. 42.12 D 37.88 D 41.25 D 39.75 D 45.00 D

60. SRK/T using 119.05

61. www.doctor-hill.com

62. AL = 23.50

64. +3.50 D +7.00 D + 4.50 D +6.00 D 0.00 D

66. US Biometry accuracy ±0.04 mm (theoretical)±0.1 to 0.12 mm (real)

67. Optical Biometry accuracy ±0.03 mm (theoretical) ±0.03 mm (real)

68. US depends on user (0.1mm ≡ 0.28 D)

69. Compression of the eye

70. Misalignment of the probe

71. Achievable accuracy in post-op. refractive error

72. US Biometry based St. Dev.: 0.8D

74. US Biometry requires a 2nd device

75. Anterior Chamber Depth

76. Compression of the anterior chamber (US)

77. Misalignment of the probe (US)

78. Contact (US) vs. Non contact (Optical)

79. Transmission of bad germs (US)

80. Risk of corneal injuries (US)

81. Compression of the eye (US, unless immersion)

83. Higher Accuracy

84. Non contact

85. All measurements in one device

86. Operator independent

87. Speed

88. Patient comfort

90. US Biometer on theoretical optic axis

91. Optical Biometer on the visual optical lineUS Biometer Optical Biometer

94. Lens Constants A-Constants are used with all IOL formulas, and are determined by the anticipated position within the eye. Surgeon Factor – is used with the first Holladay formula, and is determined by the distance from the Iris plane to the Optical plane of the implant. Effective Lens Position (ELP) is used for the Holladay II formula, and is based on the depth of the AC following Cataract surgery with the new IOL in place.

96. The advantage of a simple regression formula is that it is relatively simple to calculate. A factor can be added to a simple regression formula to compensate for a long or a short eye. (These formulas have been discredited by their authors.)

99. A1 – Measured ACD

100. A2 – Measured AL

101. A0 – Regression based on Surgical Outcomes

103. SRK II – Is a formula used in short eyes <22mm as well as in long eyes >24.5mm it uses calculations based on AL and Keratometry (Not in use by most physicians)

104. Olsen – The Olsen formula addresses four areas of concern: the calculation of corneal power, the measurement of axial length, the anterior chamber depth prediction, and the IOL optics. (European)

108. Average Eyes (22.1-24.4mm) Hoffer Q / Holladay I / SRK/T

109. Medium-Long Eyes (24.5-25.9mm) Holladay I / Hoffer Q

110. Long Eyes (25.0mm +) SRK/T / Holladay I (Holladay II All eye lengths.) (Haigis All eye lengths w/optimization)

111. Average Eye

112. Short Eye

113. Long Eye

114. Importance of your Measurements!

115. Remember!! PCIOL For every .1mm error in Calculations, there is a .19D Post-Op SURPRISE! So 1.0mm equals about 2.0D ACIOL For every .1mm error in Calculations, there is a .12D Post-Op SURPRISE! So 1.0mm equals about 1.2D

117. Clinical History Method – Is usable when both the pre-op and post-op Keratometry values are known.

123. Bit of Advice

124. Bit of Advice

125. Bit of Advice Oreo Cake-Batter Milkshake Newbury Street 352 Newbury Street Boston MA 02115 617-236-1666 Open Sunday-Thursday 11am - 11pm Friday-Saturday 11am - midnight

126. The End!!!!

127. Contact Info agraham@haag-streit-usa.com

129. www.nbcolympics.com

130. Tomey

131. www.tomey.co.jp/asia/products/products/Info/OA-1000/OA-1000.pdf

132. Dr. Warren Hill, M.D.

133. http://www.doctor-hill.com

134. JCAHPO

135. http://www.jcahpo.org

136. Google Images:

137. http://images.google.com

138. Reference:

139. http://www.reference.com

140. AAO

141. http://www.aao.org

142. WebMD:

143. http://www.webmd.com

144. ASCRS

145. http://www.ascrs.org