CATARACT 229 vey, 20 percent of all aphakics had had both eyes operated upon. With increasing cultural acceptance of surgery, increasing resources, etc., the need and desire for bilateral surgery might increase: this would also increase the amount of surgical time needed to per- form these operations. Nepal may adopt a policy of providing only one operation per person, to decrease the number of operations needed. Out of 200,000 cataract patients if 65 percent are operated on one eye (130,000 operations) and 35 percent on both eyes (140,000 operations), a total of 270,000 operations will be per- formed. Another factor that will influence projections is which of the several different definitions of "backlog" is adopted. The backlog of people blind in both eyes was chosen for the illustrations presented here. As the programme increases in effectiveness and cataract surgery is in more demand, many people not yet blind may desire surgery. Some of these people may be impaired in both eyes but not yet blind in either; others may be have cataract blindness in only one eye. In the Nepal Blindness Survey, 15 percent of those operated on for cataract could still see in at least one eye. In other words, the number of operations was approximately 115 percent the number of cataract blind people. At a cataract eye camp, a surgeon is reluctant to turn away a patient with one mature cataract and one immature cataract simply because that patient does not fit the vague operational classification of "the operable backlog." For planning purposes, it is necessary to estimate the per- centage of additional operations that will be done in patients who are not yet cataract blind. Tables 6-32 and 6--33 show the effect of different assumptions of how many people have surgery on both eyes and how many operations are done "outside the backlog." Surgical "output" depends on more than surgical skills-it also depends on effective logistics, communication, use of auxiliary per- sonnel, scheduling of travel, etc. Although a surgeon can do dozens of operations in one day under ideal conditions, it is not reasonable to assume that such rates of surgery can be sustained for a long period. If we assume each surgeon operates 200 days per year and does 15 operations per day, one surgeon can do 3,000 operations per year. If 25 operations per day are possible, one surgeon can do 5,000 operations per year. If a surgeon does 5,000 operations per year, 68 surgeon-years will be required to carry out 337,500 operations. If one assumes 3,000 operations per year, 113 surgeon-years will be needed. In other words, between 68 and 113 surgeon-years would be needed
