The number of short-sighted patients is 7
The number of long-sighted patients is 5
The number of patients requiring a varifocal lens is 4
Step-by-step explanation:
Stepwise solution-
Throughout the question, only 3 types of patients are mentioned. Hence, it would be safe to assume that he saw/sees these 3 types of patients on Tuesday.
As per the given details-
4 are neither short-sighted patients nor long-sighted patients. Then it means no of varifocal lens patients is 4.
Hence remaining total patients=16-4=12
As given, no of short-sighted patients is 2 more than the number of long-sighted patients.
Let us assume the number of long-sighted patients as “x”
Thus, the number of short-sighted patients would be “x+2”
x+(x+2)=12 (total remaining patients)
2x=10
x=5
Hence, No. of long-sighted outpatients = 5
No. of short-sighted outpatients =7
to get 
.