Table 1.

Formulas and calculations of indicators

Indicator	Calculation
Per capita GNI	INR 192,394 billion/1.38 billion=INR 139,867
Per capita GNI produced by the labor force	Per capita GNI/% of labor force=INR 139,867/0.515=INR 271,587
Direct loss of GNI due to blindness	All GNI is assumed to be due to labor force of 51.5%. Assuming that 60% of blind adults are in the age group of the labor force, Direct loss of GNI=Number of blind adults×60% × INR 271,587. To calculate the cumulative loss of GNI, we assume that there is a direct loss of GNI as children start contributing to the economy at 15 years of age with an annual economic growth rate of 5% (total blind children×per capita GNI produced by labor force at 5% growth rate for 35 years and 40 years)
Indirect loss of GNI due to blindness	Number of blind persons × 0.1 (10%) × per capita GNI by labor force. For cumulative loss of GNI due to blindness in children, we have assumed that the caregiver spends 20% of the time taking care of blind children
Economic productivity of blind	Assuming that 20% of blind adults are economically productive at 25% of the productivity level of a member of the labor force
Net loss of GNI due to blindness*	Direct cost + indirect cost−economic productivity
Cumulative loss of GNI due to blindness over the lifespan of the blind adults	Sum of net loss of GNI for 8 years and 10 years respectively at an annual growth rate (GR) of 5%
Cumulative loss of GNI due to blindness over the lifespan of the blind children	Sum of Net loss of GNI for 35 years and 40 years respectively with an annual growth rate (GR) of 5%; assuming all children contribute to labor force and caregivers spend 20% of the time taking care of the blind child
Cumulative loss of GNI due to avoidable blindness	Cumulative loss of GNI due to blindness over the lifespan of blind adults × 82.3% (calculated for 8 years and 10 years)
	Cumulative loss of GNI due to blindness over the lifespan of blind children × 35% (calculated for 35 and 40 years, respectively)
Potential loss of productivity due to vision impairment (for each level of vision impairment)	No. of vision impaired people×60% × INR 271,587×0.005 or 0.089 or 0.314
	Disability weights for mild, moderate, and severe vision impairment.[23]
All the calculations are converted to international dollars (Int$) purchasing power parity (PPP)	Int$ 1=INR 22 in the year 2020.[24,25]
	Int$ 1=INR 9.75 in the year 1997.[24,25]
All the calculations done in 1997-98 are converted to current inflation rates and compared with 2020 data.	1 USD in 1997–98 is equal to 1.6 USD in 2020.[26] Considered 2020 as the base year for our calculations.

*For children, this is the indirect cost