Terms of Use


The Nallasamy Formula is a machine learning-based IOL power calculation tool developed based on historical medical records at Kellogg Eye Center. This formula has been optimized for use with biometry data from the Haag-Streit LENSTAR LS 900 optical biometer in combination with the Alcon SN60WF biconvex intraocular lens (IOL). The Nallasamy Formula may also be used with data from other optical biometers, which provide clinically equivalent biometry data as compared to the LENSTAR LS 900. It may also be used with other biconvex IOL models in the power range of +6.00 to +30.00D WARNING: Using other data sources or IOL models than the original ones the model was derived on, may reduce the overall performance of the formula.


The Nallasamy Formula is a tool to assist physicians in selecting the appropriate IOL for their patients. The results obtained by the calculator are not intended to serve as instruction from the author. Surgeons must arrive at their own independent determination regarding the proper treatment for their patients and are solely responsible for the refractive outcome. By using the Nallasamy Formula, you agree to waive and hold the author harmless from any claims you may have arising out of your use of this tool.

Data Protection

The Nallasamy Formula is designed as a medical device and fulfils the essential requirements for this type of product, including data protection. The exchange of data with the Nallasamy Formula is done via secure and encrypted connections only and all data is stored encrypted to protect it against unauthorized access. All data identifying the patient is encrypted directly on the user’s PC and is not accessible to the service provider at any time. Only information relevant for the calculation of IOL is collected and processed by the formula. The Servers are based in the United States.


The Nallasamy Formula is based on the intellectual property of Dr. Nambi Nallasamy. It is provided for educational and clinical purposes only. The user may not reverse engineer, decompile, or disassemble the Nallasamy Formula. The user may not adapt or modify, create derivative works, operate a service bureau, or act as a Software as a Service (SaaS) provider based upon the Nallasamy Formula. The License below defines the extent of Licensee’s rights with respect to the Nallasamy Formula.

Non-exclusive, Limited License

This agreement gives the user the right to access the Nallasamy Formula and to use it for the limited purpose of performing IOL power calculations for user’s internal business, including user’s clinical operations and purposes only. Said license rights are not transferable or sublicensable, nor may the Nallasamy Formula be reproduced, or modified without the express prior written consent of Dr. Nambi Nallasamy. Licensee agrees to use all reasonable efforts to prevent unauthorized use, distribution, disclosure or publication of the formula or any data generated using the formula. By this license, the user acquires no ownership right, title or interest in the Nallasamy Formula, or in any applicable patents, trademarks, copyrights, trade secrets and other intellectual property rights which may be embodied or contained therein.

Patient Information and Cookies

Use of the Nallasamy Formula may involve the entry of certain patient data, which may be deemed “protected health information” (“PHI”) under the Health Insurance Portability and Accountability Act of 1996 and Standards for Privacy of Individually Identifiable Health Information, 45 CFR Parts 160 & 164 (“HIPAA”) as amended or supplemented by additional legislation or regulations from time to time. All data is encrypted during transfer of the data from the original computer and the server. The data provided is stored for the purpose of improving the performance of the Nallasamy Formula and research. The Nallasamy Formula website uses cookies to facilitate easier navigation within the site and provide a higher level of convenience for the visitor. A cookie is a small piece of information about an Internet session that may be created when a visitor accesses a web site. The cookies used by the Nallasamy Formula website are not written to the visitor’s hard drive, exist only until the browser is shut down, do not contain any personal information regarding the visitor, and do not retrieve any information from the visitor’s personal computer.

No Warranties

The Nallasamy Formula is provided “as-is” without any warranty whatsoever. The users assumes all risks and responsibilities for IOL power selection by the calculator to achieve the user's intended results, for the use of the calculator, and for the use of any results obtained from the calculator and shall indemnify and hold Dr. Nambi Nallasamy harmless from and against all loss, cost, claims or damages arising out of the user’s use of the Nallasamy Formula and the information contained in or compiled by the calculator. to the maximum extent permitted by applicable law, and in all states and jurisdictions where such disclaimers are permitted by law, Dr. Nambi Nallasamy expressly disclaim all representations and warranties regarding the calculator, either express or implied, including but not limited to implied warranties of merchantability, fitness for a particular purpose, and non-infringement. Dr. Nambi Nallasamy expressly disclaims any warranty, either express or implied, regarding system and/or calculator availability, accessibility, or performance. by accepting these terms, the user hereby acknowledges that, at any given time, the Nallasamy Formula may not be available or may become unavailable due to one or more of the following: periodic system maintenance, technical failure of the Nallasamy Formula, telecommunications infrastructure, or delay or disruption attributable to viruses, denial of service, increased or fluctuating demand, acts or omissions of third parties, acts of god, or any other cause reasonably beyond the control of Dr. Nambi Nallasamy.

Limitations on Liability

The user hereby expressly assumes the entire cost of any damage resulting from the user’s use of the Nallasamy Formula and the information contained in or compiled by the calculator and shall indemnify and hold Dr. Nambi Nallasamy harmless from and against all loss, cost, claims or damages arising out of the user’s use of the Nallasamy Formula and the information contained in or compiled by the Nallasamy Formula. To the maximum extent permitted by applicable law, and in all states and jurisdictions where such limitations and exclusions are permitted, in no event will Dr. Nambi Nallasamy be liable for any damages whatsoever (including, without limitation, direct, indirect, special, consequential, punitive, or incidental damages) arising out of the use of or inability to use the formula, even if Dr. Nambi Nallasamy has been advised of the possibility of such damages.

Terms and Conditions

Upon acceptance of the terms of this Agreement by clicking “I agree” below, the user will be bound by the terms of this Agreement. Dr. Nambi Nallasamy reserve the right to change this policy at any time. This Agreement cannot be modified except by Dr. Nambi Nallasamy. This Agreement shall be governed by and interpreted in accordance with the laws of the United States, without giving effect to its conflict of law provisions. This Agreement may be terminated by Dr. Nambi Nallasamy at any time for a violation of its terms; any failure by Dr. Nambi Nallasamy to immediately address or enforce any aspect of this Agreement shall not be considered a general or continuing waiver of such right of termination. Dr. Nambi Nallasamy may discontinue temporarily or permanently the Nallasamy Formula and the availability of the Nallasamy Formula to the user or to others at any time, in their sole discretion.