Managing cataract outcome

SPEAKER 1: Welcome to this presentation on managing cataract outcome. By the end of it, you should be able to– describe the impact of outcome on surgical services, understand the World Health Organization guideline for cataract outcome, and relate to managing and monitoring cataract surgical outcome in eye units. There are several interconnected factors that affect the sustainability of cataract services. Firstly, to deliver efficient surgical services, we need to maintain high output. And this has to be balanced with providing high outcome of surgery to maintain patient confidence. Low cost of surgery is another key factor that helps fuel demand for services.

It is essential to achieve sustainable eye care for a population within their health system in order to reduce blindness from avoidable causes.

Quality of cataract surgery can be measured in three ways– psychological, the patient perspective. This is often linked with satisfaction with surgery. Functional, what patients are able to do before and after surgery. And physiological, a measurement of the vision in the operated eye. Psychological and functional measurements are subjective, and very difficult to standardise. The physiological measurement uses the change in vision acuity to provide an objective perspective on a patient status before and after surgery.

In 2005, a review of data from many population-based and rapid assessment surveys indicated that poor outcomes– less than 6/60– were being found in between 21% and 53% of all operated eyes, across a range of eye units. Most of these poor outcomes were due to aphakia, or breakage of spectacles. Since then, intraocular lens, IOL, implementation, has become the norm in cataract surgery. There have been additional improvements in surgical techniques as well, such a small incision cataract surgery, and phacoemulsification. As a result, we can now expect much lower rates of poor outcome.

The World Health Organization has produced a guideline for the visual outcomes that should be expected from cataract surgery. Outcomes are classified as good, borderline, or poor. And the outcome is good if visual acuity after surgery is equal to or better than 6/18 in the operated eye. An outcome is borderline, if acuity is worse than 6/18, but equal to or better than 6/60. And any acuity less than 6 /60 is classified as a poor outcome. Eye units should aim to have good outcomes in over 80% of all operated cases, at two month follow-up with available correction, or 90% with best correction.

Ideally, borderline and poor outcomes should be found in less than 5% of all cases with best correction, or in up to 15% of cases with available correction. These guidelines can be applied in high and low volume settings, and across static, and outreach service delivery models.

Impact of poor outcome. Vision less than 6/60 after surgery has a range of impacts. Naturally, has a direct and devastating impact on the individual patient, whose expectations have not be met. It also impacts on the reputation of the hospital or service provision and at community level, often creating a long term mistrust of health providers. Reputation at the professional level also needs attention, as issues for training in ethics. Poor outcome means fewer patients and decreased output. Fewer cases done means higher costs. Over time, these factors will challenge the sustainability of the service delivery, and the whole eye care programme may fail. Eye units need to look at outcome measures as a high priority and take corrective action.

There are several causes of poor outcome– selection of patients for surgery; co-morbidities, for example, can impact final outcome; surgical complications, resulting from technique, procedure, or even lack of facilities; failure to provide spectacles to correct postoperative refractive error can reduce benefit to the patient, and finally, sequelae, which are late post-operative complications, such as posterior capsule opacification.

Management to minimise poor outcomes begins at admission stage. A clear examination protocol and vision of assessment should provide a sound understanding of any underlying comorbidities.

Pre-operative selection of cases, particularly in busy high volume settings, should follow up protocol, so that patients with preexisting eye diseases, such as glaucoma, or posterior segment disease, are not missed. And patients need to be prepared and counselled accordingly. Surgical complications such as technique, infections, or appropriate IOL, are important issues which are often overlooked in under-resourced settings. They’re all due to human and infrastructure factors, and can be addressed through good management and training. In the post-operative period, spectacle correction is often a simple intervention that is missed out in poor resource settings. But it should be considered an essential component of service provision. Patients should be made aware of sequelae, and appropriate intervention provided.

Evidence from high volume settings that follow rigid protocols, shows that they also achieve high outcomes.

Eye units need to monitor their cataract surgical outcomes to reduce overall complication rates and provide a reliable quality of service. It is also important to provide the team with feedback to give insight into achievements, and take corrective action when needed. Monitoring should not be used to compare outcomes between surgeons or eye units, as outcome is dependent on many factors besides the skill of a surgeon. It is essential that this is explained to the team before monitoring is implemented.

Monitoring can be implemented manually in low resource settings. It uses a relatively simple tally sheet to record information at two stages on every 20 patients operated for cataract surgery. Information is noted on each surgery, including any problems, IOL implantation, and surgeon. Postoperative vision is recorded at discharge, and then again during follow up at four to six weeks, and classified into good, borderline, or poor. If the outcome is poor, the reason is given– selection, surgery, or spectacles. Information is collected for 100 cases, and then a report is prepared for the team to assess. Management should identify and train a nurse or clerk on how to enter and analyse all the data.

In settings with computers, there’s software available with a similar data entry form. The advantage here, is that the reports can be generated automatically for every 100 cases, and be made available graphically. The software is free to download from the internet. Monitoring reports provide direct information on the percentage of good, borderline, and poor outcomes, and also on the causes of poor outcomes at discharge and follow up. Additional information can also be gained on the age and gender of patients, the first or second eye operations, visual acuity pre- and post-operatively, which can be used to understand the site restoration rate, the percentage of IOL implantations, and operative complications by month. This is important for infection control.

In conclusion, for good cataract surgical outcome, there are three clear steps to follow. One, use IOLs in everyone and always refract post-operatively.

Two, know your outcomes by monitoring service provision using a manual tally sheet or computer software. And three, take practical measures to avoid complications.

Good outcomes of cataract surgery lead to high volume, sustainable eye care services.