Symposium on Quality and Demand for Cataract Surgery

Eur J Implant Ref Surg, Vol 7, February 1995

ESCRS LISBON

SYMPOSIUM ON QUALITY AND DEMAND FOR CATARACT SURGERY

CHAIRMAN: ULF STENEVI, SWEDEN

PARTICIPANTS: MATS LUNDSROM, SWEDEN; JURGEN STROBEL, GERMANY; EMANUEL ROSEN, UK; TETSURO

OSHIKA, JAPAN; THOMAS v. CRAVY, USA; STEPHEN OBSTBAUM, USA.

Introductory Remarks

ULF STENEVI

Department of Ophthalmology University Hospital Lund, Sweden

Recently, I had the opportunity to talk to 10 different colleagues from 10 countries. When I asked them 'What is good quality cataract surgery?' I got 10 very long answers. Unfortunately they were all different.

If we ask our patients we also know that their views on good quality cataract surgery are different from the surgeons. The reflects the fact that we do not have internationally-accepted criteria for defining what is good cataract surgery or the proper handling of our cataract patients. This is in spite of the fact that cataract surgery is probably the most commonly used surgical procedure on a world-wide basis.

If we look at the estimated number of cataract surgeries/lOOO members of the population performed in different countries (Fig. 1), we can see that it varies greatly. We also find that even if countries are very close together geographically, such as

Fig. 1

0955-3681/95/010034 + 15 $08.00/0 34

Sweden and Norway, there can be noticeable differences in the number of cataract operations performed.

This raises 2 other questions 'Why should this be?' and 'What is a really acceptable level?'. Our symposium participants will be facing those questions, as well as others including 'Who benefits from it?', 'Who needs it?', 'When and how should we operate?' and 'At what cost?'. We will also be exploring the cost/ benefit, how quality should be measured and how many operations we should be performing.

Who Benefits from Cataract Surgery?

MATS LUNDSTROM

Department of Ophthalmology Karskrona Central Hospital Kariskrona, Sweden

When we ask which patient benefits from a cataract extraction, a quick answer could be: a patient with a cataract of some importance leading to visual impairment or disabilities which affect everyday activities. The patient should also have a physical and mental status that allows surgery to be performed safely with no major complications.

By benefit for the patient, we mean fewer perceived problems including improved performance of daily activities, such as employment and ability to drive a car. Other benefits are better visual acuity and relief from glare and double vision, etc.

Recently we published a study about the most common disabilities perceived by patients undergoing a cataract extraction. The most frequent problems were the ability to recognize faces, read books, newspapers and TV-text, walk on uneven ground, do fine handwork and go shopping.

Many of the everyday problems faced by patients requiring cataract surgery are caused by glare, double vision, halos, etc., which suggests that even with improved vision after surgery, reduction in glare can be a substantial benefit and an indication for surgery.

Another problem is the visual disparity between the patient's 2 eyes when only the 1st eye undergoes surgery. Some patients may be unaware of this problem and may live very comfortably with it for

© 1995 W.B. Saunders Company Limited

Symposium on Quality and Demand for Cataract Surgery

the rest of their lives. Other patients suffer constantly until the 2nd eye surgery has been performed. In fact, a 1990 study by Brenner reported that the most satisfied patients were those without ocular morbidity who had undergone 2nd eye surgery.

In another recent study, Steinberg and associates found that there was a stronger correlation between postoperative change in perceived problems and change in visual acuity in the better eye than between changes in perceived problems and visual acuity in the operated eye. Our own study found a good correlation between postoperative improvement in binocular visual acuity and the decrease in perceived problems. However, there was a large variation from one individual to another.

PATIENT AGE

Among the preoperative factors that may influence the outcome of surgery is the age of the patient. For example, Brenner has reported that while older patients benefited by improvements in their reading abilities, they were still below average with respect to activities requiring mobility. We have also shown that older patients generally had fewer problems than young patients before surgery, the reduction of perceived problems after surgery was less than it was in young patients. However, it is well established that the visual outcome is lower in older patients than in the young.

OCULAR CO-MORBIDITIES

Other studies have shown that co-existing eye disease, such as diabetes or glaucoma, can have an adverse effect on visual outcome. This suggests the expectations of patients with these or other ocular co-morbidities should be fully understood.

OTHER DISEASES

Because other diseases and handicaps occur as people get older, bad vision may pose an extra burden that may reduce their daily activities even further. Therefore, early surgery in some of these patients may prolong the period of independent living.

COGNITIVE PROBLEMS

We are also aware that although impaired cognitive


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functions that may accompany age may affect our ability to measure the benefits of surgery, it should not be considered as a contraindication for surgery.

PERSONAL PREFERENCES

The benefits of surgery are also heavily influenced by the patient's personal preferences for performing specific activities, such as playing the piano, porcelain painting, hunting, driving a car, etc., but those preferences can vary from one patient to another.

TIMING

In most cases, it is not a question of if a cataract extraction be performed but when. Personally I advocate early surgery before too many of the patient's activities have been abandoned. The right time relates to different visual acuity values and different stages of the disease in different patients. It may also be influenced by geographical, social and health care availability from one area to another.

SOCIAL WELFARE

If the social welfare system means that patients with bad vision can have mobility, transportation and community help at a reduced price, they will not want to give up these benefits after a successful cataract extraction.

Based on all of these considerations, I suggest that we try to find out what will be the expected level of visual functioning after a successful cataract operation. That level might be influenced by a cataract in the other eye but differences in outcome because of 1st or 2nd eye surgery should be taken into account. Therefore we need a good data base with built in reference material which will allow creation of a model which will show not only that the surgical goal has been achieved but also the magnitude of improvement.

We also require better instruments to assess patient benefit. Thus, the increasing rates of cataract extractions can only be justified by a substantial benefit for our patients. Sooner or later we will have to prove that there is a benefit to health care authorities, as well as to our colleagues in other specialties and to ourselves.

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Economy and Cataract Surgery

JURGEN STROBEL

Department of Ophthalmology, University of Jena, Jena, Germany

Over the last 20 years, cataract surgery has changed tremendously and we must now ask ourselves what are the best and quickest procedures and what are their results and consequences? However, although we carry out cataract surgery for the benefit of the patient, it is difficult to calculate its cost-effectiveness in terms that government funding agencies will understand and appreciate.

Table 1 Pre-surgery medications - systemic

Costs in DM

0.48 Atropine 0.72 Luminal 1.68 Dipitilor 0.51 Tranxilium

3.78 DM Total

We can of course calculate the benefit to the patient on the basis of the work they lost before undergoing surgery and we must all work towards cost reductions. There is a balance between the money that is earned and how much money must be paid for surgery. When we analyse those payments we must calculate how much we have to pay the administration, how much we have to pay for housing, how much for investigations, how much for doctors and nurses, etc. Finally, we must pay for the things that we pay before, during and after surgery.

Table 2 Pre-surgery medications -local

Costs in DM

2.60 Chibroamuno 0.20 Mydrum 0.61 Gentamycin 3.80 Neosynphrin 0.39 Zykolat

7.60 DM Total

For example, presurgical costs will include both systemic and local medications (Tables 1 and 2), which in our hospital amounts to just over 10.00 DM. (One US dollar is about 1.5 DM. That is an extremely small amount; 'peanuts'.)

We also find that the pre-surgery costs in the surgery centre come to 57.71 DM. Of course those


Table 3 Pre-surgery/surgery centre

Costs in DM

0.46 Conjucam 2.53 E153 3.80 Neosynphrin 0.99 Zykolat 1. 75 Injection 0.63 Maxidrin 0.65 Oxygenium Infuser 0.63 Injection fixation 0.90 Infusion set

36.09 Claforan i.v. 0.42 Injection set 0.42 Pads 7.95 Oiniset 1.09 Xylocitin

57.71 DM Total

Table 4 Cover materials, etc_

Costs in DM

1.70 Tegaderm 1.94 Surgeon head 5.84 Surgeon head 2 2.43 Mouth 2.43 Face 2.55 Brush 7.93 Cover Instruments

71.21 Cover set 6.12 Gloves 2.47 Fluid packet

104.48 DM Total

costs can vary from surgeon to surgeon or from centre to centre (Table 3). We must also take into account the cost of materials, such as masks, gloves, drapes, etc. That totals 104.48 DM (Table 4).

Although most surgeons think that the implant is the major expenditure during surgery, it represents only about a third of the total costs (Tables 5 and 6), whereas suturing materials cost about 30 DM. However, if you use Healon and a high quality heparin-surface modified IOL, those can be very

Table 5 Materials during surgery

Costs inDM

53.40 Needle set 27.87 Alcon BSS 43.17 Misostat 2.85 Filter 9.00 Lancet

195.00 Healon 335.00 IOL 45.44 BSS 75.90 Phacoset

167.00 Phaco infusion set

954.63 DM Total



Table 6 Costs during surgery-suturing

Costs in DM

35.41 Nylon 10/0 7.07 Supolene

42.48 DM Total

Table 7 Post-surgical costs

Costs in DM

5.90 Eye drops 2.40 Forlecortin 1.13 Gentamycin

9.43 DM Total

Table 8 Single use items

Costs in DM

69.00 Pre-surgery 104.48 Cover material 997.11 During surgery

9.43 Post surgery

1180.02 DM Total

expensive items. Post-surgical costs are minimal (Table 7), while much of the expenditure goes to items that we use only once (Table 8).

We can conclude that because most of the money we expend is in the operating room during surgery, this is the area in which we can think of reducing the costs of surgery. At the same time, we must also take into account another major cost, i.e. the personnel that we need to enable us to perform effective cataract surgery.

What is Acceptable Cataract Surgery?

JOSE GUILHERME CUNHA-VAZ

Department of Ophthalmology, Coimbra University Hospital, Coimbra, Portugal

The question is: What is acceptable cataract surgery?

Basically, it is the surgery that everyone is doing, because in a sense it is an attitude. I am sure that everyone is convinced that he is doing acceptable and good quality surgery. Of course we must realize that good cataract surgery is not something you can


37

do as a cook book situation. Every surgical procedure cannot always be the same for every patient; each situation must be considered on its own.

There are different types of cataract, with different complication rates, each of which may require a different surgical approach. In addition, the patient's understanding of the situation is fundamental and should be dealt with. We should also be more concerned with evaluating the patient's quality of life before and after surgery.

We may also ask: what is an acceptable complication rate?

We know that the complication rate can be influenced by the type of cataract, whether the eye is or is not in active inflammation prior to surgery, the patient's history and other factors. You also have to consider the preoperative examination, the choice of anaesthesia, and the IOL you will be implanting.

These are all important and all have economic consequences. So when you are performing what is considered to be acceptable surgery you must consider all of these things together. You must consider your own knowledge, understanding and experience of the process you are using, while remembering its economic and environmental consequences.

The economic variables that influence you predominately include the cost of the anaesthesia, the time of the physician and how long it takes the patient to recover and go back to work. Although we do not always consider them as such, new technologies can be cost-effective because they can accelerate the patient's recovery and return to normal life and in many cases improve their living conditions.

Basically, the best surgery is the one that gives the best opportunity for full recovery with full vision, and these things can, in the end, pay for the expense of the new technology.

Several studies have suggested that cataract surgery is clearly .the most cost effective surgery being carried out throughout the world.

For example, Javitz and Javitz showed in 1983 that the costs of technology can be re-paid within three months. Medical costs may go up because more people are using the new technology. But at the same time, because people get better more rapidly, they are paying back the costs to society. They are increasingly active, pose fewer problems for their family and are generally happier.

When we ask ourselves: which technique or techniques are the most effective safe and predictable and which are the best guidelines to follow, our own personal experience is important but the best answers will come from well prepared and carried out clinical trials. Because such clinical trials provide uniform methods for data reporting and statistical analyses, they are urgently needed.

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These trials may be tedious and difficult to perform, but they can be an essential support for the surgeon. They increase his confidence because he has at his disposal reliable scientific data which he can use to answer any questions that may come up in his own practice.

In the absence of good clinical trials, we rely on our own personal experiences, which may include thousands of surgeries, for our judgements on what kind of visual acuity and visual stability we can expect. But in our own experience we may have made changes in our techniques and procedures without really remembering the changes we have made.

Finally, I believe one of the biggest challenges for ophthalmic and cataract surgery is to be able to measure the changes that are happening when we perform surgery. We must be able to quantify changes in inflammation that may occur, changes in the cornea, the rate of healing, and the formation of secondary cataracts.

We must also develop improved methods for measuring visual acuity, corneal function, the lens capsule, and any oedema which is present and may be a particular problem for the aging retina. Being able to measure these things becomes increasingly important as we go to minimally invasive surgery in which we are trying to obtain the best results with the least trauma and aggrl'!ssion and with the most rapid, efficient and cost-effective methods we can employ.

One way to help fill the need for improved quantification of our surgical results would be to establish specialized functional evaluation centres throughout the world. Of course the cost of these centres would be enormous, but they could prove invaluable for defining criteria for surgical indications and quality control of our surgical procedures. The activities of these centres could also be correlated with clinical questionnaires sent to ophthalmic surgeons throughout the world. Perhaps the ESCRS will be able to promote the formation of these centres at least in Europe.

The Demand for Cataract Surgery in Europe

EMANUEL ROSEN

Manchester, UK


in cataract surgery. At the same time, the common need for cataract surgery is based on very similar demographic principles.

As Ulf Stenevi and other speakers have shown there is a disparity between supply and demand in Europe. We as ophthalmologists are responsible for this disparity, as are health care purchasers and providers of health and medical resources. This is because we are sending conflicting messages to those purchasers as to what the need for cataract surgery is.

Because we are living in an ageing population on a worldwide basis, there is an increase in the amount of surgery that is needed. On the other hand, this need for surgery transfers to a smaller percentage in terms of demand because not everybody who requires surgery comes forward to ask for it. In addition, there is a lesser percentage in which the appropriate action is taken. There is a move underway at the present time to lower the threshold of cataract surgery even further towards so-called clear lens extraction procedures, which undoubtedly improves visual performance.

In 1992 in the British Medical Journal, Wormald attempted to explore the scope of visual problems in elderly patients over 65 years of age using the criteria of blindness, low vision, visual impairment and cataract (Fig. 1).

He found that cataract accounts for 75% ofthe low vision cases, while individuals with low vision constitute about 7.7% of the world population based on WHO standards and 10.6% according to USA criteria. Therefore, 6-8% of the older than 65 population suffer from cataract and therefore are candidates for surgery. That compares to 0.1-1.4% of the population who undergo cataract surgery each year, suggesting that there is a demand that is not being met.

Europe is a disparate collection of nations with disparate health care systems, resources and skills Fig. 1



In another study, Rosenthal showed in 1985, that 46% of a random population more than 76% had lens opacities, 46% had age-related macular degeneration and 6.6% had glaucoma. In 1987, Pizzarello (Fig. 2) reported that 91 % of individuals between 75 and 85 had lens opacities. However, he and Roberts in the UK found that only 28-35% had what could be considered as visual defects due to their cataracts. That means that a third of these individuals have treatable cataracts.

We are also aware that the incidence of visual deficit, cataract and medical problems increases with a variety of risk factors such as poor economic and social conditions, the greater the amount of sunlight exposure, etc.

Geoffrey Jay and his associates in Glasgow (Fig. 3) have also shown that from 1980 to date, the rate of cataract surgery in patients older than 75 has grown from 7.1% to 10.5% and for those between 65 and 74 from 3.6% to 4.2%.

They also found that the proportion of cataract surgery relative to other eye operations increased

Fig. 2

Fig. 3


39

from 19.3% to 37.5% between 1977 and 1988 and that the visual acuity indications for surgery in patients older than 70 have also decreased.

As other participants in this symposium have shown, the daily visual tasks that are influenced by cataract-associated visual deficit are decreased ability to read, to recognize things and people, ability to drive and to move about freely. As such, the patient's subjective symptoms and desires for improvement are important indications for surgery.

Although we don't have any absolute tests for determining the thresholds for surgery, if we are sensible, we will listen carefully to the patient, do some measurements to assess their visual disabilities and to place them in the context of their visual needs.

At the same time, there has also been an increasing refractive component in the indications for surgery as the quality of surgery has improved and the interest in refractive surgery has increased. In fact, the main refractive surgical procedure practiced by all of us is lens or cataract surgery.

In the UK, the Royal College of Ophthalmologists has recently published a set of provisional guidelines for cataract surgery and its contraindications (Fig. 4). Their contraindications include a patient who is not willing to undergo surgery or who doesn't need it, individuals who are satisfied with glasses or other visual aids, or a patient whose life style will not be changed appreciably by cataract surgery.

The guidelines also suggest that surgery may not be suitable for patients with other medical conditions or in whom the risks outweigh the benefits. In addition, high risk surgery should not be carried out without the patient's full and informed consent.

With respect to performing bilateral simultaneous cataract surgery, which also figures in the debate on cost effectiveness of cataract surgery and patient rehabilitation, the Royal College guidelines (Fig. 5)

Fig. 4

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decry its routine performance and suggest that it should only be performed by a competent surgeon when justified by several indications, including refractive, age-related macular degeneration and high degrees of ametropia. The patient's age and economic considerations should also be taken into account.

Therefore we ultimately come down to the matter of resources, which in turn depend on the health care system. In general, the allocation of resources for ophthalmology must be shared with the allocation for cataract surgery.

In addition, private health care, depending on the country, may mop up some of the demand, but it is important to keep in mind that cataract surgery accounts for from 60-70% of all ophthalmic surgery. When any commodity or service is not subject to a price mechanism, it will have to be rationed in some way if any real attempt is to be made to match supply with demand.

We know that with respect to cataract surgery we are faced with an ageing population whose needs may be neglected. Yet, while there are finite resources, here is an infinite demand fuelled not only by the patients but by ourselves as we exercise our own clinical judgments.

At the same time, it is our responsibility to influence health care providers as to which cases are most deserving of treatment. It is also clear that the health care providers have to balance the need for heart surgery and hip replacements or treating the mentally ill against the demand for ophthalmic and cataract surgery.

These considerations suggest that clinical decisions are based largely on need and that it is up to us to educate the providers of health resources so that we get an appropriate proportion of the available resources.

In that respect, it is worth pointing out that 70%

Fig. 5


of all costs in the British National Health Service go to salaries of surgeons, nurses and support staff and not to those involved in cataract surgery. Here again, there is a need for education.

It is also important that we educate the public that cataract surgery at its best yields excellent results, neutralizes ametropia and provides very rapid rehabilitation. An educated public in turn can create the public opinion that will influence the providers of the resources to deliver our fair share.

We also need to educate ourselves to make certain that we give the proper messages and that they do not conflict with the indications for surgery as we know them. We should also inform optometrists and family doctors so that they can give suitable advice to cataract patients about what is possible today.

The Quality and Demand for Cataract Surgery in the Far East

TETSURO OSHIKA

Toyko, Japan

I would like to report on a recent survey carried out among members of the Japanese Society of Cataract and Refractive Surgery which reflects current trends in Asia. It was based on responses from 836 members in 1992 and 880 in 1993.

In 1993, the total numbers of cataract surgeries in Japan was about 380000, compared to about 900000 in India and much smaller numbers in Korea, Singapore, Taiwan, China and the Philippines (Fig. 1).

With respect to cataract surgeries 1000 population, there were 3.0 in Japan, about the same proportion in Taiwan and 4.1/1000 in Singapore. The

Fig. 1



Japanese figure is about half what it is in the United States. For India, Korea, the Philippines and China, the respective numbers were 1.2, 1.1, 0.3 and 0.1/1000. Those low values undoubtedly relate to poor access to hospitals, poor education insurance coverage, and the limited number of cataract surgeons.

The Japanese survey showed also that the duration of hospitalization ranged from 5 to 10 days for about a third of the patients, with about 18% remaining for from 3 to 4 days. We also found that the percentage of patients undergoing cataract surgery on an outpatient basis increased from 24% to 36% between 1992 and 1993.

In addition, there was an increase in the percentage of surgeons performing phacoemulsification in Japan, from 33% in 1993 to 42% in 1993. There were also increases in Korea and Singapore (Fig. 2), but it does still not appear to be the procedure of choice in east Asian countries.

With respect to anaesthesia procedures in Japan, there was a decline for retro + akinesia from 67% of the respondents in 1993 to 48% in 1993 and an increase in the number of surgeons performing subTenon anaesthesia during the same period (Fig. 3). For both ECCE and phacoemulsification, the preferred anaesthesia procedure was retrobulbar + akinesia.

As in other countries, there was a steady increase in the number of cataract surgeries with IOL implantation in Japan, from 100 000 in 1987 to 290000 in 1993. By far the most popular anterior capsulotomy technique was continuous circular capsulorhexis, used by 83% of ophthalmic surgeons in 1993.

The increase in cataract surgery in Japan is almost certainly due to the fact that all costs for cataract/IOL surgery are reimbursed by the public medical insurance system, which includes US$1600

Fig. 2


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for surgery and IOL and full coverage for hospitalization.

Between 1992 and 1993, there was a substantial decrease in the percentage of surgeons performing ECCE, from 41% to 27%, mirrored by a smaller decrease in the percentage of those performing single-handed phacoemulsification (Fig. 4). Over the same year period there was an increase in the number of surgeons performing dividing phacoemulsification techniques.

The Japanese survey showed also that the percentage of surgeons who preferred phacoemulsification increased between 1992 and 1993, regardless of the age of the surgeon. However, younger surgeons were more likely to perform phacoemulsification than their older colleagues.

Similarly, 48% of the surgeons surveyed said that they had a high interest in performing small incision surgery compared to 39% in 1992. There was also an increase in the use of silicone IOLs and a decline in the percentage of oval PMMA and small PMMA IOLs for respondents performing small incision surgery (Fig. 5).

Fig. 3

Fig. 4

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Those who said that they did not perform phacoemulsification in 1993 (41%) said that the main reason was that they did not have the equipment, while smaller percentages cited complications or difficulties with learning the technique.

In 1992 and 1993, the most promising IOLs for small incision surgery were judged to be the silicone and soft acrylic lenses, mirrored by a decline in preference for the use of hydrogel and PMMA IOLs (Fig. 6). About a third of the Japanese surgeons said that the minimum age limit for IOL implantation was 40, with 27% indicating that they would implant IOLs in patients as young as 20.

With respect to wound closure, similar percentages preferred either running sutures of self-sealing incisions (Fig. 7). The most popular sizes of the IOL optics they used with phacoemulsification were 5.5 mm and 6.0 mm while most of those who performed ECCE preferred a 6.5 mm optic.

On a scale of 0-5.0, interest levels in modified IOLs for surgeons who considered the various options in 1993 were 3.5 for surface modified IOLs, 4.1 for UV blocking lenses, 3.6 for coloured IOLs and 3.0 for multifocals.

Fig. 5

Fig. 6


Fig. 7

The survey indicates that Japanese surgeons are moving more and more towards small incision cataract surgery and that there is an increase in the volume of cataract surgery and its expanding indications. In other east-Asian countries the number of cataract surgeries will have to be doubled or possibly tripled by improving access to hospitals and increasing the surgical manpower.

What can Computer Analysis Teach us about Quality of Cataract Surgery?

THOMAS V. CRAVY

Santa Maria, California, USA

Since the beginning, ophthalmologists have passed down surgical techniques from generation to generation. These techniques have evolved from 'seat of the pants' clinical impressions. Today we have at our disposal powerful desk top computers and versatile software which easily permit a precise quantification of surgical results and statistical comparisons. If we only make the effort to carefully enter these routine measurements, we take before and after surgery, into a computer data base, many truths are just waiting to be discovered.

In this presentation I will explain how computer analysis took me from creating limbal incisions with a 10.0 nylon shoelace suture to unsutured 5 mm lateral pocket incisions. The difference of -1.75 D ATR shift and almost 3 D total decay from the first week through 4 years is compared with a total of 1/3 D WTR shift with a total change of 0.01 D from the first week through 1 year. That's what I would call worthwhile evolution; and the evolution continues.



My 1st example is a study of patients having had planned ECCE via a perpendicular limbal incision which was closed with a 10.0 nylon shoelace suture. Calculation of the surgically-induced astigmatism (SIA) keratometric decay curve using the mean Cravy Kt and the Jaffe K2 magnitude were plotted on a linear time scale (Fig. 1). We observed that a typical spike at 1 week is followed by a quick fall and stabilization.

When we extended the analysis from 6 months to 10 years, a subtle trail off of the curve at about 22 weeks became obvious as a precipitous decline in wound strength as the nylon began to hydrolyse (Fig. 2). No sutures were cut or removed. There was also a steady ATR shift out to at least 4 years and an additional 1.5 D decay after initial stabilization. On the other hand, the plot of the Jaffe K2 magnitude failed to give any indication of the wound dynamics.

At the 1992 ASCRS meeting in San Diego, Dr Jack Holladay presented the Holladay/Cravy/Koch (HCK) formulas for Cross Cylinder Difference (Fig. 3). The crossed cylinder difference of XCD is merely the difference between the with-the-wound (WTW) and

Fig. 1

Fig. 2


43

against-the-wound (ATW) values predicted by the HCK calculations. There are 2 pairs of WTW and ATW values at peak and at the reference meridian (RM).

The absolute value of the Peak XeD is always equal to the magnitude of astigmatism of surgically induced refractive change (SIRC) in the H/C \ K system. It is also equal to the Jaffe K2 magnitude and the Naylor magnitude. When the RM is set to 90 0 as it almost always should be, the value of the XeD at the RM is equal to the N aeser KP. These identities tie together the several methodologies. The Cravy Kt is not identical to any of them, but is very close to the N aeser KP and XeD at 90.

The 4 popular formulas for calculating surgically induced changes in astigmatism (Figs. 4 and 5) show that the Cravy, N aeser and H/C \ K peak XeD formulas all reflect the important wound dynamics illustrated by the data set. However the Jaffe does not and neither would Naylor or HCK MOA.

The previous data are based upon interpolated values of Cravy Kt. When the interpolated data are compared with what I refer to as windowed data, both techniques reveal the important wound

Fig. 3

Fig. 4

44

dynamics in this group of patients. The more windows there are, the closer the windowed data curve resembles the interpolated data curve.

For the interpolation of data for 2 patients, (Fig. 6), represented by the 2 curves, the actual visit values of Kt are indicated by rectangles and the interpolated values by circles. For each week bracketed by visits, a value will be derived by linear extrapolation. Therefore, all values summated for 4 weeks will be the best available for that period, etc.

By comparison, windowing requires a target with plus and minus tolerances. Figure 7 represents targets of 1, 4, 8 and 12 weeks while the width of the window in these cases is 10% of the postoperative target time. One patient had visits at 2.2 and 6.2 weeks which do not fall into the windows and are not included in the data analysis. Interpolation adjusts the variables such as Kt and optimizes time. Windowing utilizes the actual variable at the expense of accurate time.

In a study presented in the JASCRS in 1989, we examined 2 incision groups, limbal and scleral

Fig. 5

Fig. 6


pocket and 4 suture types in each incision group. All incisions were 9.5 mm for planned ECCE; all closures were in a shoelace configuration and no sutures were cut or removed.

Because of its poor performance in the limbal group, it was replaced with 11-0 Mersilene in the scleral pocket group. At the end of a 6-year follow up, the only statistical significance was for 10-0 prolene in the scleral pocket group.

In trying to reduce congenital ATR astigmatism at the time of routine cataract surgery I moved the incision to the side and correlated the aggregate induced astigmatism curve against linear time in weeks. The absence of the usual late decay then lead me to perform routine lateral incisions for cataract surgery.

We also compared the results of identical surgeries (ECCE) except for the fact that we compared the effects of a superior 9.5 mm scleral pocket incision vs a lateral incision of the same type and size. The incisions were closed with an 11-0 Mersilene suture which was never cut or removed. From the first week after surgery the total amount of change was dramatically different for the 2 groups and at 3 years the difference in favour of the lateral incision was statistically significant at P < 0.001 (Fig. 8).

When we compared the aggregate results of phacoemulsification with either a superior or lateral 6.5 mm pocket incision closed with an 11-0 Mersilene shoelace, the lateral incision again demonstrated substantially less overall decay and excellent long-term stability (Fig. 9).

In another study comparing the effect of lateral scleral pocket incisions either 6.0 or 6.9 mm in length, both closed with an 11-0 Mersilene shoelace, we found that the 6 mm group took longer to stabilize and averaged about 0.5 D with WTR shift compared to 0.25 D WTR for the 5 mm group. However, the difference was not statistically significant.

Fig. 7



However, when we compared unsutured incisions of the same sizes, the 6 mm incision shifted more at about 0.5 D WTR than the 5 mm at about 0.25 D. The difference was statistically significant (P< 0.02).

When 6 mm sutured and unsutured incisions were compared, the differences in shift were not statistically significant. Neither was there any statistically significant difference when we compared the 5 mm sutured and unsutured incisions.

From these studies we conclude that for the superior ECCE incision, no incision and suture combinations performed adequately. In addition, they were far less stable than lateral incisions. For lateral incisions, the long-term results were the same whether sutured or not. Finally, we found that un sutured lateral incisions have slightly less WTR shift than larger ones.

Our study suggests also that it is very important to insure the accuracy of the data being fed to the computer and that there must be adequate follow-up to establish stability. Two weeks and sometimes 2 years is not enough.

We also found that one must use a proper

Fig. 8

Fig. 9


45

algorithm and that the Jaffe, Nagel and HCK/MOA mean magnitude plots are not useful for aggregate analysis of wound dynamics. On that basis, I suggest use of either the Cravy, Naeser or HCK XeD astigmatism formula. I also prefer interpolation to perform time-course data analysis and if time windowing is used, it must be done with strict window criteria.

The Demand for Cataract Surgery in the USA

STEPHEN OBSTBAUM

Director of Ophthalmology Lenox Hill Hospital, and Cornell Medical College, New York, NY, USA

In the United States, the national ambulatory medical care survey which sampled patients from doctors' offices can give us some idea of the incidence of the disease while the National Hospital Discharge Survey provides strong indices of the discharges in various census areas. In addition, the National Health Interview Survey tells us about its prevalence in a population. Recently, the Health Insurance Experiment also told us about insurance payments and co-payments and how much has to come out of their pockets when they receive a service or procedure.

With respect to what the patients really need to take care of their particular condition, we must take into account incidence and prevalence rate and must also look at future population estimates from census data. However, at present we do not have answers to all those questions.

In the United States, Wayne Powell has been pulling some of that information together for us and will have presented his findings at the 1994 American Academy of Ophthalmology meeting. Basically he has used several different data bases to show that in the United States, there was a rise in cataract surgery from the 1986 figure of 700 000 until 1991 when it reached a plateau of 1 250 000 and has declined somewhat since then.

However, his figures are based on demand, that is utilization of cataract surgery vs. what the true need might be (Table 1). But with any kind of model that might be done, there is an inherent danger. If we look at the number of full time equivalents, or hours the practitioner really devotes to his patients, the average American ophthalmologist devotes 42 of his 48 hour work week to direct patient care (Table 2).

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Table 1 Current estimate of need and demand for cataract surgery in the United States

Current need/procedures/yr Current demand/yr

1878000 1169000

Figures based on NAMCS data and workforce need.

Table 2 Number of FTEs required for cataract care-1994 (1 FTE = 2106 hours of care)

Need

Demand

Medical surgical Medical surgical

1567 1952 904

1079

Table 3 Future FTE need for cataract care

Year

2000 2010

Medical

1836 2124

Surgical

2286 2647

It can also be shown that the need for cataract surgery, including medical and surgical components, is clearly less than the number of people out there who are doing the work and the demand may be even less (Table 3).

The danger is that in using such models, although the numbers do increase with the passage of time, fewer people than estimated are really needed to do the work. But that is the model and does not really represent what happens in real life.

It concerns me that when we are looking at the numbers that are available to us, we should remember that we want to look at the quality, the cost effectiveness and outcomes of any intervention that we undertake. Outcome management really makes an inter-relation between the quality of medical care, which we have as yet been unable to measure and with the issue of health service cost; not only in ophthalmology, but across the board.

The purpose of outcome management is to be better able to control the end results of medical intervention. This in turn is rooted in clinical issues and decisions that result in possible cost/quality trade-offs.

A real challenge that faces us is our patients' expectations. Their main concern is not just paying for what they get. They want the new technology, but also want to know how safe it is, and if there are adverse reactions, how can we prevent them from occurring. Basically, they are interested in costeffectiveness and their wishes, at least in the United States, will play an increased role in the decisions that will be made.

We must also be concerned about the impact if


health care reforms in the United States, which will be guided by the movement of market forces, along with increased cost restraints and perhaps capitation.

Furthermore, there will be an increased focus on provider performance, that will result in greater competition for patients.

That competition in turn will be based on costs, patient satisfaction and clinical outcomes. That is why it is so important for us to be able to measure outcomes.

We must also be aware that those who are dictating policy, as it affects our profession and our patients, think more on a societal level rather than at the level of the single patient. As practitioners we are concerned with our patients and what their outcomes are after we make a particular intervention.

On the other hand, policy makers are looking at the societal, big picture issues, to make their decisions about what is appropriate and cost-effective, good quality care and practice.

As Dr Cunha-Vaz pointed out, I agree that we must make sure that we are not only able to measure the quality of our care but also that we are able to quantitate its measurement. That is something that we need to do not only in the United States but also on the European and international levels.

Many of us shun the notion of practice guidelines because we think it is an imposition on what we do. The reality is that as we move into the next century practice guidelines will emerge. As a result, what we really need is to be able to measure what we as ophthalmologists and as leaders can provide to the people who are the ones who will be making the decisions as to how we practice.

Discussion

STENEVI - Dr Obstbaum, are there any plans for creating any new data bases in the United States?

OBSTBAUM-Right now at least in ophthalmology there are 2 initiatives; 1 by the ASCRS and 1 by the Academy to start looking at outcomes data. Implicit in collecting outcomes data will be collecting the types of information that we think are important not just for cataract surgery but for glaucoma and corneal surgery, as well as other types of interventions or services that are not interventional. There is a move afoot in the United States for that to happen, but it will take time.



STENEVI-Dr Lundstrom, can you say how far the Swedish national register has been coming along?

LUNDSTROM- We started with our National Register in 1992 and it now covers about 95% of all cataract surgeries performed in Sweden. In October we will pass 100 000 cataract extractions. We can look upon this register as encompassing the whole country. Now we don't have to guess about demography and visual acuity before surgery any more; it's all there. That is because of the dedication of all cataract surgeons in Sweden to their profession and patients. One interesting finding is the great variation in setting priorities and about the indications and benefits for our patients.

STENEVI - Dr Obstbaum, what do you think are the most important parameters that we should measure? You can't measure everything.

OBSTBAUM - I think in this rapidly-evolving field, as ophthalmologists, we can take credit for that because I was president of the Cataract and Refractive Society at the time and contracted with Harvey Branagh at Johns Hopkins to do the initial study on patient outcomes. I think this study should capture things that would help determine what we are really doing for a patient postoperatively. Measures of activities of daily living and glare and things of this nature can really make a difference. If we look at some ofthe studies we see that there is a very poor correlation between visual acuity from a Snellen chart and what the patient sees and how well the patient is satisfied. Satisfaction has to be measured in other ways. I think that once we give up telling the patients that you see 20/20 and ask them can you drive better, or can you sew better, etc., we will really be confronting the important issues.

ROSEN - One of the really frustrating things in participating in this debate - particularly from the European point of view - is the absolute lack of data which we have all complained about. Apart from Sweden and the United States, I don't know of any European country in which the data is collected in an organized way. Can Mats Lundstrom and Steve Obstbaum tell us how much these systems cost? That is something we will have to consider if we implement similar data collecting systems in Europe. Who will pay for these things and what budget will provide the money?

LUNDSTROM-The cost of running a national database is not that overwhelming. At this moment


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we are mostly collecting data preoperatively and postoperatively from a few clinics.

ROSEN - What mechanisms do you have for achieving good compliance from your surgeons. You have a more limited number than we have in the UK and I can't foresee that without someone to do it for the surgeons that we will be able to collect the data in a cost-effective way.

OBSTBAUM-The data available in the United States, as I indicated, is flawed, so that is why I think that the ophthalmologists themselves take an active role in collecting this type of data. There is no doubt that it is important to look at costs up front but if you consider what the potential costs might be down the road if you don't collect the data, things could be exponentially worse. We have to persuade everyone in the audience that it is important to do these things. If we don't preach to the choir then somebody will be preaching to us later on.

STENEVI - Can Dr Cravy - with his excellent computer background - tell us how we might get some useful answers to some of the questions that have been raised here?

CRA VY - In my presentation I tried to make the point that it is highly worthwhile for individual doctors to have an ongoing database in their practice and to segregate different doctors in the practice, the hospital and in the community. All of the surgeries could be pooled so that we could do an aggregate analysis of the cataract surgeries performed in the United States. If every doctor were keeping his own individual data base, they could all be put together and analysed.

STENEVI - Do you employ someone to collect your data or do you do it yourself. If you do it yourself wouldn't you be doing more effective work looking at patients?

CRA VY - Well I had to marry my data collector but there are easier ways to do it. I was so interested in this that I spent several years writing the software to collect the data and perform the analysis. I think that most doctors who get involved in .this are so interested in the outcome and results that the whole office can become involved. It doesn't take a very skilled person to enter the data and to read what the acuities are, from a chart. In fact, I have given users of the software program that I have written instructive audiotapes which are sufficiently helpful that 99% of them can assign the data to other members of staff.

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ROSEN -Dr Cunha-Vaz has stressed the need for good randomized clinical trials to evaluate which is the best way to do the things that we are doing. Surely the problem with cataract surgery is the time that it takes to mount a trial. By the time you get the results, a particular technique used in the trial may have become obsolete.

CUNHA-VAZ-I would like to emphasize that we should not only be content to measure visual acuity but we should also take quality of life outcome into account. It is also important that people involved in cataract surgery collect the necessary data before someone else tells us what to do. There is now a movement underway in the European union to create clinical centres in ophthalmology and other fields which will be able to evaluate and correlate the effectiveness of standardized procedures. Of course you should not change techniques in a trial, but if they are done properly and the right questions are asked it should not take too long to do such trials.

OBSTBAUM-In the United States a very unpleasant and I believe dangerous factor is that


doctors are being paid differently than in the past. We used to be paid a fee for service; when you prepared a bill you would be reimbursed for whatever you did when you could bill and be reimbursed for whatever you did. Now with the managed care system in the United States, the third party payer, i.e. the insurance carrier, lays the dollars on the table and says 'This is all you are getting for 200 000 people'. Divide it as you see fit. At the same time, we want to reduce your utilization by 10% in the next year. That is why outcomes are so important today. In the past, if a doctor was getting a 20% vitreous loss you might turn your head, but now if he has to take the patient back for retinal detachment repair, he is taking money that might otherwise be coming to you. In the midwest where I am very involved in managed care and serve as network manager for 1000s of people, the surgeons are now saying, we want outcomes to determine which surgeons can do which procedures the best. That is another major force developing in the United States and if you have no data on outcomes you have no practice guidelines. If you have no outcomes, there is no way you can work and survive in this managed care environment.


Documents

Symposium on Quality and Demand for Cataract Surgery