Differences

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--- srk [2026/07/22 15:43] – [Step 8: Refraction Correction] Scott Larson
+++ srk [2026/07/28 12:31] (current) – Scott Larson
@@ Line 1: / Line 1: @@
 ====== SRK/T (Sanders-Retzlaff-Kraff/Theoretical) Formula ======
-FIXME
 The SRK/T is a third-generation IOL power calculation formula combining theoretical optics with empirical regression optimization, published by Retzlaff, Sanders, and Kraff in 1990.
@@ Line 47: / Line 47: @@
 Using the Pythagorean theorem applied to corneal dome geometry:
-$$ H = r - √(r² - (Cw / 2)²) $$
+$$ H = r - \sqrt{r^2 - \left( \frac{Cw}{2} \right)^2}* $$
 ----
@@ Line 78: / Line 78: @@
 The IOL power for emmetropia is calculated using a modified vergence formula:
-$$ \text{IOL}{\text{emme}} = \frac{1000 \times na \left( nr \times r - nc \times L{OPT} \right)}{\left( L{OPT} - ACD{est} \right) \times \left( na \times r - nc \times ACD{est} \right)} $$
+$$ \text{IOL}{\text{emme}} = \frac{1000 \times na \left( na \times r - nc \times L{OPT} \right)}{\left( L{OPT} - ACD{est} \right) \times \left( na \times r - nc \times ACD{est} \right)} $$
@@ Line 84: / Line 84: @@
   * **na** = refractive index of aqueous/vitreous (1.336)
-  * **nc** = corneal refractive index (optimized, typically 1.333)
+  * **nc** = corneal refractive index (1.333)
-  * **nr** = retinal refractive index
-----
 ===== Step 8: Refraction Correction =====
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   * The **T2 modification** (Sheard et al., 2010) later addressed nonphysiologic behavior in the corneal height calculation step
+=====Reference=====
+[[https://docs.eyefixer.org/Cataract/IOL%20Calculations/Development%20of%20the%20SRK_T%20intraocular%20lens%20implant%20power%20calculation%20formula.pdf|Development of the SRK/T intraocular lens implant power calculation formula. Retzlaff et al. J Cataract Refract Surg. 1990;16:333-339]]
+{{tag>cataract}}

cataract