Epidemiology & Technology

Blog Archive

Estimating Indian zonal populations in 2024 using two data sources

The MOHFW projections The UN Population projections : My age groups of intertest were: 0-1516-3031-4546-6061-75>75Age groups of Interest In order to arrive at Administrative zone wise estimate populations for 2024, for my age grousp of interest, I recently used the following methodology: The Estimated population in each zone in each
October 11, 2024

Understanding Cataract Prevalence and Operated variables in RAAB

black flat screen computer monitor
There are various ways that cataract can be defined when analysing data from RAAB surveys. Here, I review the RAAB Analysis R scripts to understand how it is being done in the autogenerated tables. Understanding the case_when syntax This syntax is used very commonly for creating new variables based on
August 9, 2024

Using RAAB6/RAAB7 Analysis R scripts on Desktop

The RAAB team has provided the analytic scripts on the GitHub repo. Once you download the scripts, you need some configuration on your desktopn to be able to use them. First is obviously you need to install R package. You also need to install pandoc [from here] Then you need
August 8, 2024

Global Estimates of Blindness and Visual Impairments

Data from various global estiamates are summarized here for easy reference: Link to my personal google sheet: https://docs.google.com/spreadsheets/d/1iTgBmRA4VwWE1fzRKA1YD1fzzMvn90Vu/edit?usp=sharing&ouid=113111648583609130450&rtpof=true&sd=true Pascolini, 2010 NUMBERS (millions)WorldIndiaPopulation6737.901181.40Visual Impairment ( PVA < 6\18)285.3962.62Blindness (PVA < 3\60)39.378.08Low Vision (< 6\18-3\60)246.0254.54PREVALENCE (1000 per million population)WorldIndiaVisual Impairment ( PVA < 6\18)42.3653.00Blindness (PVA < 3\60)5.846.84Low Vision (< 6\18-3\60)36.5146.17 20102010GLOBALGLOBALBlindness PVA
May 29, 2024

Visual Acuity Conversion Chart

In order to simplify my life when dealing with variations in Visual Acuity Charts when dealing with data from different surveys, I have created the following table for VA conversions What about PL+ / PL-, FCCF etc LogMAR for 1/60 vision is 1.78, rounded off to 1.8 as used in
April 22, 2024

ICD 11 Vision Categories

When analyzing data from blindness surveys, one needs to map out visual acuity against the Visual impairment categorized in ICD. There are some nuances, especially w.r.t Moderate visual impairment (MVI) based on the charts used as some VA charts yield 6/18 vision while others yield 6/19. ICD11 Categories Based on
April 22, 2024

Stata Code for generating corneal opacity outcomes from RAAB 6 surveys

grayscale photography of person's eye
Corneal Opacity Related Outcomes There are four sets of variables Stata Code The above Stata code can be used by anyone under a CC-BY-SA license.
January 12, 2024

RAAB6 Surveys Stata Commands for Cataract Surgical Outcomes

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The WHO Eye Care Indicator Menu has prescribed many core indicators. The Core Indicator 6 is Cataract surgical outcome (visual acuity) in the domain of Output – Eye Care Service Quality Definition: Percentage of eyes with: Estimation of these indicators can be accomplished using the below Stata code I have
August 6, 2023

Stata Code for eCSC and CSC calculations

WHO has identified WHO Effective Cataract Surgical Coverage (eCSC) as a key indicator for monitring Universal Eye Health. LINK There is a slight change from the prior formulae used for eCSC in papers by Ramke et al and the one published by Keel et al. Further, the original CSC estimation
March 14, 2023