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Subha's Ophthalmic Page
search information related to IOL, biometry, corneal topography, etc.
If you are new to my site:



Understanding Tecnis PureSee IOL
Explains how does the Tecnis PureSee IOL provide depth of focus and intermediate vision to patients.
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Mar 26, 202510 min read
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ETDRS vs Snellen chart
Difference between the Snellen chart and the ETDRS chart based on logmar
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Mar 13, 20251 min read
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Diffractive orders with multifocal IOLs, echelette design and the concept of chromatic aberration correction
standard way of diffractive trifocal IOL manufacturing has been to use the 0 order for distance, & the +1 & +2 orders intermediate & near
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Mar 8, 20258 min read
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Understanding spiral optics designed Rayner Galaxy Intra Ocular Lens
Since the launch of the RayOne Galaxy lens, there has been a significant amount of attention focused on spiral optics and how such design provides multiple focal points to provide depth of vision to patients. The adoption of spiral optics to provide such multifocality in IOLs or contact lenses is new, and not many literature is available that would help a layman like myself, to comprehend. So here I set out to reflect what I have understood whatever reading material is availa
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Mar 1, 20258 min read
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Negative Dysphotopsia- Video explanation
This is a video explanation on negative dysphotopsia, its causes, symptoms, and treatment options.
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Jan 19, 20251 min read
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Classification of monofocal, enhanced, and EDOF IOLs based on performance on defocus curve
Adapted from the JCRS https://doi.org/10.1097/j.jcrs.0000000000001502
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Dec 15, 20241 min read
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Biometry case study-Selecting right patient for multifocal IOLs
A case study detailing how to avoid a bad outcome by looking into the IOL calculation or biometry page throughly
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Dec 8, 20240 min read
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How patient axial length, corneal power and effective lens position affect the near-vision with a multifocal lens
Recently, Filomena and co-authors ( https://doi.org/10.1097/j.jcrs.0000000000001502 ) presented evidence based scientific classification of partial and full range vision lenses. Based on their classification, I could summarize the following: a) IOLs that provide more than 2.3 diopter of pseudo-accommodation at .2 log mar (6/9.5 or 20/32) in the defocus curve can be classified as full range of vision IOLs b) IOLs that provide less than 2.3 diopter of pseudo-accommodation at
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Nov 27, 20242 min read
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How the Barrett Universal II formula works - impression from a user
The following video content is an impression of how the Barrett Universal II formula works. Barrett Universal II is an unpublished...
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Jul 27, 20241 min read
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