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Cataract

Globally, cataract ( Opacification of the lens) is the single most important cause of blindness, and cataract surgery has been shown to be one of the most cost-effective health-care interventions. Cataract is related to ageing and cannot be prevented, but cataract surgery and insertion of an intraocular lens are highly effective, resulting in almost immediate visual rehabilitation. In well-managed eye units, high quality, high-volume surgery is possible, one ophthalmologist being able to undertake 2000 to 5000 or more operations a year, as long as there are adequate support staff, infrastructure and patients who are able and willing to access the facilities.

Table 4: The estimated number of cataract cases in people aged 50+ populations

  BCVA<3/60 BCVA<6/60 BCVA<6/18
Zone N Prev. n Prev. n Prev.
Mechi 2,092 1.30% 4,103 2.60% 11,485 7.20%
Koshi 2,817 1.20% 6,991 3.00% 23,296 9.80%
Sagarmatha 2,029 0.80% 4,798 2.00% 17,492 7.20%
Janakpur 4,004 1.30% 8,413 2.60% 31,114 9.80%
Bagmati 699 0.20% 1,282 0.30% 7,014 1.90%
Gandaki 1,592 0.70% 5,124 2.20% 20,973 9.10%
Narayani 12,539 5.40% 34,428 14.90% 49,832 21.50%
Lumbini 3,579 0.90% 9,862 2.50% 23,550 6.00%
Rapti 422 0.30% 1,050 0.80% 3,760 3.00%
Dhaulagiri 346 0.40% 748 0.90% 3,342 3.90%
Bheri 2,092 1.40% 3,704 2.50% 11,393 7.70%
Karnali 93 0.50% 274 1.40% 748 3.90%
Mahakali + Seti 3,622 1.40% 5,766 2.30% 12,072 4.80%
Nepal (2001) 35,925 1.30% 86,543 3.10% 239,702 8.50%
Nepal (2011) 46,263 1.30% 111,446 3.10% 308,676 8.50%


Estimates of numbers and proportions of eyes (two eyes of bilateral blinds and one eye of unilateral blinds) in various district/zones who are blind (VA<6/60) in eyes due to cataract is shown in Table 5. The cataract surgical burden and its calculation of annual incidence are calculated on the basis of survey findings conducted in respective zone in recent years and shown in Annexure (Table 31).

Table 5: Estimated number of eyes with cataract and BCVA<3/<0, <6/60 and <6/18 in 50+ population

  BCVA <3/60 BCVA <6/60 BCVA <6/18
Zone Eyes Prev. Eyes Prev. Eyes Prev.
Mechi 12,322 3.90% 18,148 5.70% 34,422 10.80%
Koshi 15,795 3.30% 29,195 6.20% 65,081 13.70%
Sagarmatha 14,197 2.90% 21,501 4.40% 49,966 10.30%
Janakpur 26,197 4.10% 38,651 6.10% 93,851 14.80%
Bagmati 11,989 1.60% 14,564 2.00% 30,109 4.10%
Gandaki     19,571 4.20%    
Narayani     92,725 20.00%    
Lumbini     34,593 4.40%    
Rapti 4,525 1.80% 6,933 2.80% 15,938 6.40%
Dhaulagiri 3,201 1.90% 4,584 2.70% 11,460 6.70%
Bheri 14,503 4.90% 19,190 6.50% 40,376 13.60%
Karnali 1,007 2.60% 1,527 3.90% 2,866 7.40%
Mahakali + Seti 25,877 5.20% 31,923 6.40% 49,756 9.90%
Nepal (2001) 129,613 6.60% 333,104 11.90% 393,825 20.10%
Nepal (2011) 183,162 6.60% 428,954 11.90% 556,531 20.10%


There are estimated about 429,000 eyes as backlog of cataract blind eyes (BCVA <6/60), representing almost three quarter of all causes of blindness due to eye diseases in the country. The main no modifiable risk factor is ageing. Other frequently associated risk factors are injury, certain eye diseases (e.g. uveitis), diabetes, ultraviolet radiation and smoking. Cataract in children is due mainly to genetic disorders. Visually disabling cataract occurs far more frequently in Terai area of the country than in hilly area, and women are at greater risk than men and are less likely to have access to services. The cataract surgical rate—the number of cataract operations per million population per year—is a quantifiable measure of the delivery of cataract surgical services. It is meaningful, however, only when it includes all cataract operations performed in a country, including those in the private sector and during outreach, and when the population size and age structure can be defined. Cataract surgical coverage indicates the number of individuals with bilateral cataract causing visual impairment, who have received cataract surgery on one or both eyes, in other words, the proportion who were eligible for surgery and who received it. This indicator is used to assess the degree to which cataract surgical services meet the need. The data are obtained from population-based surveys.

Cataract is included as major activities in the national plans for the prevention of blindness, and cataract surgical rates are increasing in recent years. Cost-effective surgical techniques have been developed and tested and are being improved continuously (e.g. small-incision cataract surgery and use of good quality, low-cost intraocular lenses)

Table 6: Cataract surgical coverage in different zones of the country (2010, in persons)

  CSC (persons) <3/60 CSC (persons) <6/60 CSC (persons) <6/18
Zone Male Female Total Male Female Total Male Female Total
Mechi 75.9 73.6 74.7 70.1 59.5 64.3 46.6 37.1 41.1
Koshi 85.9 74.8 79.1 72.5 57.5 62.9 39.2 38.3 38.7
Sagarmatha 87.7 79.3 82.6 71.4 67.2 68.9 44.4 39.6 41.5
Janakpur 87.9 81.1 84.1 76.8 69.8 72.7 46.7 47.6 47.2
Bagmati 96.8 96.2 96.5 94.2 94 94.1 76.4 75.6 76
Gandaki       68.1 52.6 59.5      
Narayani       39.3 35.8 37.3      
Lumbini       61.7 70.8 66.6      
Rapti 94.8 92.3 93.5 92.7 81.5 86.5 75.8 64.4 69.3
Dhaulagiri 89.9 67.7 70.5 83.8 78.3 81 59 51.3 54.9
Bheri 83.2 82 82.4 71.3 75.7 74.1 50.7 54.6 53.1
Mahakali + Seti 80.7 84.1 82.7 74 76.8 75.6 61.4 61.9 61.7
Nepal
(weighted)
87.6 82.9 84.6 72.4 68.8 70.2 55.7 53.5 54.5


Table 7: Cataract surgical coverage by zone in the country in 2010 in eyes (in %)

Zone CSC (eyes) <3/60   CSC (eyes) <6/60   CSC (eyes) <6/18  
Male Female Total Male Female Total Male Female Total
Mechi 62.1 53.4 57.5 52 41.7 46.4 35 26.2 30
Koshi 69.1 58.2 62.6 52 41.9 45.9 27.3 26.9 27.1
Sagarmatha 62.3 62.4 62.4 49.7 51.9 51 29.4 30.1 29.8
Janakpur 72 65.5 68.4 61.4 54.9 57.8 35.5 34.1 34.8
Bagmati 78.3 79.8 79.1 74.6 76.1 75.5 60 58.9 59.3
Gandaki *                  
Narayani *                  
Lumbini *                  
Rapti 80.7 75.6 78 74.1 64.4 68.7 52.1 45.6 48.5
Dhaulagiri 73.4 67.7 70.5 65.6 58.4 62 42 35.9 38.8
Bheri 62.2 62.2 62.2 52.9 55.7 54.6 33.3 36.6 35.3
Karnali 77.1 62.4 69.9 64.8 52.5 58.8 50.9 35 42.5
Mahakali + Seti 57.7 61 59.6 51.5 55.4 53.8 39.6 42.9 41.5
Nepal
(weighted)
68.9 65.7 67.1 59.5 56.6 57.9 40 38.8 39.4


Fig 7: Cataract Surgical Rate
Cataract Surgical Rate

Table 8: Visual outcome of cataract surgery (PVA)

Zone IOL   Non-IOL   Total  
good b-line poor good b-line poor good b-line poor
Mechi 60% 22% 18% 0% 14% 86% 56% 21% 23%
Koshi 66% 22% 12% 17% 29% 54% 62% 23% 15%
Sagarmatha 81% 16% 3% 18% 15% 67% 73% 16% 11%
Janakpur 73% 17% 11% 25% 18% 57% 67% 17% 16%
Bagmati 81% 11% 9% 59% 5% 36% 79% 10% 11%
Gandaki 73% 17% 6% 44% 6% 50% 64% 15% 21%
Narayani 57% 33% 10% 24% 28% 48% 48% 32% 20%
Lumbini 64% 28% 8% 16% 25% 59% 59% 28% 14%
Dhaulagiri 64% 22% 14% 56% 6% 38% 64% 21% 15%
Rapti 67% 18% 15% 0% 2% 98% 58% 16% 25%
Bheri 68% 18% 14% 42% 25% 33% 63% 19% 18%
Karnali 81% 10% 9% 37% 17% 46% 66% 12% 22%
Mahakali + Seti 74% 17% 9% 48% 18% 34% 67% 17% 16%
Nepal
(weighted)
70% 20% 10% 30% 17% 53% 64% 20% 16%


Table 9: Visual Outcome of Cataract Surgery (BCVA)

Zone IOL Non-IOL Total    
good b-line poor good b-line poor good b-line poor  
Mechi 77% 10% 13% 10% 19% 71% 73% 10% 17%  
Koshi 74% 15% 11% 17% 33% 50% 69% 16% 15%  
Sagarmatha 85% 13% 2% 22% 22% 56% 78% 14% 8%  
Janakpur 86% 6% 8% 40% 36% 25% 81% 9% 10%  
Bagmati 85% 9% 6% 64% 9% 27% 84% 9% 8%  
Narayani 85% 8% 7% 61% 17% 22% 79% 10% 11%  
Gandaki 88%     64%     80% 7% 13%  
Lumbini 89% 5% 6% 52% 27% 21% 85% 8% 7%  
Dhaulagiri 75% 18% 7% 56% 13% 31% 74% 18% 8%  
Rapti 80% 10% 10% 19% 58% 23% 73% 16% 12%  
Bheri 77% 12% 11% 49% 21% 30% 71% 14% 15%  
  Karnali 89% 6% 5% 65% 15% 20% 81% 9% 10%
  Mahakali + Seti 86% 6% 8% 56% 17% 27% 78% 9% 13%
  Nepal
(weighted)
83% 9% 8% 45% 24% 32% 78% 11% 11%

 

Limitations:

The main limitations are lack of adequate resources and accessibility to surgical service and inadequate political will to address cataract blindness as a national public health issue. In many rural and remote districts, there is no regular cataract surgical service. High-quality, low-cost cataract service models are commonly used in other parts of the country, but their uptake in these areas is low, due to local conditions such as cost, distance and ignorance about the services. The main barriers to uptake of cataract surgery in poor communities are lack of awareness, availability and quality of service, high cost of treatment (direct and indirect cost) and limited access to eliminate blindness due to cataract.

Aim:

Elimination of blindness due to cataract.

Objective:
Provide cataract surgical services at a rate adequate to eliminate the backlog of cataract over a number of years, at a price that is subsidized and affordable for all people, both rural and urban, in an equitable manner, and with a high success rate in terms of visual outcome and improved quality of life.

Strategies:

  • Create demand for services by overcoming barriers to the uptake of cataract surgical services. The approaches recommended include enlisting community health workers to identify people with cataract and to provide follow-up and rehabilitation after surgery. Priority should be given to patients who are bilaterally blind from cataract; however, patients should be encouraged to seek treatment before becoming blind, thereby reducing their dependence on the family and society, and this should be taken into consideration in calculating the desired cataract surgical rate.
  • Develop and mobilize local manpower and resources to provide cataract services. Training and use of mid-level personnel for screening will allow ophthalmologists more time for surgery.
  • Promote services at a cost that all patients can afford. This might require bulk purchase of consumables and different tiers of payment, whereby fees from high-income patients are used to subsidize services for low-income patients. Introduce cost-effective methods and techniques for cataract surgery.
  • Promote services that are close to where people live. Community outreach to remote areas should be conducted where appropriate. Screening for new cases is acceptable only when surgical services are in place so that newly identified patients can be treated. Short-term surgical camps may not be appropriate in a long run except under specific circumstances.
  • Provision periodical or regular cataract surgical service in all 75 district headquarters and plan static and mobile cataract screening program at sub district level.
  • Create network between cataract surgical center at district with all primary eye care centers and health posts for referral of patients requiring cataract surgery.
  • Identification of operable cataract should be provisioned at health post or sub health post level.
  • Mobilize VDC resources for the poor patient requiring cataract surgery
  • Promote high-quality surgery with a good visual outcome. Intraocular lenses should be used for all patients, unless contraindicated. Monitoring of the outcome of surgery should be encouraged to improve quality. Provide facilities and promote practices and behavior that are acceptable to patients.

Targets:

  • Cataract surgical rate: Prevention of blindness program planning should include achievable targets for increasing the cataract surgical rate to the desired level, which should be the rate required to eliminate cataract-related severe visual impairment calculated on the basis of data for the local population. The rate will depend on the prevalence of cataract causing visual impairment, the visual acuity recommended for eligibility for surgery and demographic trends based on current CSR rate and estimated incidence of blindness in the country. In average condition, it has been assumed that one should achieve more than 6000 CSR per million populations to eliminate cataract blindness. District wise annual cataract surgery targets based on incidence rate and CSR are provided in Annexure (Table 31).
  • Cataract surgical coverage: Ultimately, the highest possible cataract surgical coverage (at least 90% among PVA (6/60 in cataract eyes) should be reached. Monitoring cataract prevalence at district and sub district level and using cost-effective methods for assessing cataract surgical coverage will allow identification of gaps, so that services are targeted to areas and subgroups at greatest need.
  • Quality of cataract services: WHO recommended targets for the quality of cataract surgery will be met, i.e. at least 80% of eyes achieve 6/18 or better presenting visual acuity postoperatively and 90% with best correction
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