Survey of the clinical use of glare and contrast sensitivity testing Douglas D. Koch, M.D., John F. Liu, M.D.
ABSTRACT In August 1988, we surveyed a random 10% sample of the members of the American Society of Cataract and Refractive Surgery about their use of contrast sensitivity and glare testing. Of 396 surveys mailed, 214 were returned for a response rate of 54.3%. Thirty-six percent of respondents used glare testing alone; 5.6% used contrast sensitivity testing alone; 23.4% used both test modalities; 35% used neither. The most common uses of glare and contrast sensitivity testing were to evaluate visual function in patients who have cataracts, secondary cataracts, and/or intraocular lens problems.
Key Words: cataract evaluation, contrast sensitivity testing, glare testing, Snellen acuity
The limitations of Snellen acuity testing in assessing visual function have stimulated the development of new modes of visual testing. In particular, glare and contrast sensitivity testing provide important information about visual function that can supplement Snellen acuity readings. 1 ,2 These tests are potentially of greatest importance for patients who have relatively good Snellen acuities yet complain of significant visual disability. Because of advances in surgical techniques, such patients are often candidates for surgery. There are therefore obvious scientific, medicolegal, and, more recently, regulatory reasons for fully documenting their degree of visual disability. We wished to determine how extensively glare and contrast sensitivity testing were used by ophthalmologists with a known interest in cataract surgery. We conducted this survey prior to the imposition of guidelines for cataract surgery by the state peer review organizations (PRO), thereby eliminating the effect of external regulatory requirements on usage.
MATERIALS AND METHODS In the summer of 1988, we sent a 15-question survey to 396 American ophthalmologists, selecting every tenth name on the alphabetical membership list of the American Society of Cataract and Refractive Surgery. We selected this sample size to maximize our accuracy in determining the percentage of members using glare and/or contrast sensitivity in their practices. We assumed that 50% to 75% of the members used one or more of these tests. Our sample size of 396 members gave an alpha error of 0.025 for a minimum error of 0.05 at a usage level of 65% to 70%. This means that there was only one chance in 40 of having a greater than 5% error in determining the actual level of usage among those surveyed. To maintain strict confidentiality, the questionnaires and return envelopes were not marked or labeled. All questions were multiple choice; some required only one answer and others permitted a selection of several answers. The questions solicited information on the respondents' reasons for using or
From the Cullen Eye Institute, Houston, Texas (Koch), and Waco Eye Associates, Waco, Texas (Liu). Reprint requests to Douglas D. Koch, M.D., 6501 Fannin NC-200, Houston, Texas 77030.
J CATARACT REFRACT SURC-VOL 16, NOVEMBER 1990
707
Table 1. Incidence of glare and contrast sensitivity testing. U sed neither
35.0%
Table 2. Indications for glare and contrast sensitivity testing.
Indications
Glare
Contrast Sensitivity
Cataracts
98%
94%
U sed one or both
65.0%
Used both
23.4%
U sed glare only
36.0%
Secondary cataracts
62%
63%
Total glare use*
59.4%
Intraocular lens problems
28%
35%
Used contrast only
5.6%
Corneal problems
17%
19%
9%
27%
Optic nerve diseases
8%
31%
Glaucoma
0
31%
Total contrast use*
Retinal diseases
29.0%
*Includes the 23.4% who used both
not using glare and contrast sensitivity testing, the indications for their use, the preferred devices, advantages and disadvantages of these tests, and the impact of these tests on their practices. Responses were coded, entered into a computer database, and analyzed using the Statistical Analysis System (SAS) on an IBM-compatible computer. RESULTS We received responses from 214 of the 396 surveyed-54.3%. Sixty-five percent (65%) used contrast sensitivity and/or glare testing in their practices (Table 1); 59.4% used glare testing, and 29% used contrast sensitivity testing. The most frequent indication for glare testing was cataract evaluation, followed by secondary cataracts, intraocular lens evaluation, and corneal problems (Table 2). The primary indications for contrast sensitivity testing were similar, although a higher percentage of respondents also used contrast sensitivity to evaluate glaucoma, optic nerve diseases, and retinal diseases. The respondents indicated they used these tests primarily on cataract patients to assess visual function more accurately (Table 3). Other reasons included enhancing patient understanding and medicolegal factors. Respondents were evenly split in their selection of cataract patients on whom these tests were used. Approximately 50% used them on all patients complaining of glare regardless of Snellen acuities, whereas the other half used them only on patients who complained of glare despite having good Snellen acuities (Table 3). Seventy-seven percent (77%) of those using glare testing and 41 % of those using contrast sensitivity testing indicated that, in selected patients, these tests served as a final arbiter in determining the need for surgery (Table 3). Among users of these tests, the great majority indicated that Snellen acuity was the most accurate 708
J CATARACT REFRACT
means of assessing visual function in cataract patients (Table 4). Contrast sensitivity testing was felt to be the least effective by slightly more than 50% of this group. By far the most popular glare tester was the Brightness Acuity Tester (BAT), followed by the Miller Nadler Glare Tester, and the True Visual Acuity (TVA). The most popular contrast sensitivity system was the VCTS charts (Vis tech Corp.), with smaller numbers using the TVA and various other systems (Table 5). Respondents gave several reasons for selecting particular glare and contrast sensitivity devices,
Table 3. Use of tests in cataract patients. Glare
Contrast Sensitivity
Reasons for use Accurate visual function assessment
95%
84%
Patient understanding
65%
58%
Medicolegal
41%
21%
4%
11%
48%
52%
50%
40%
Marketing Patient status All patients with glare regardless of Snellen acuity Only patients with good Snellen acuity and glare All patients with good Snellen acuity regardless of visual complaints All patients Use in selected patients as arbiter to determine need for surgery
SURG-VOL 16, NOVEMBER 1990
6%
7%
19%
23%
77%
41%
Table 4. Users' ranking of effectiveness of visual function tests in cataract patients. Most*
Least*
Snellen acuity
73%
18%
Contrast sensitivity
19%
56%
Glare
14%
21%
Table 5. Devices used. Glare
Contrast Sensitivity
BAT*
65%
Vis tech charts§
Miller Nadlert
24%
TVA
16%
TVA:j:
13%
Other
11%
Other
8%
79%
*The percentages in these columns do not add up to 100% because some responders ranked more than one test as most or least effective.
*Brightness Acuity Tester (Mentor 0 & 0, Inc., Norwell, MA) tMiller Nadler Glare Tester (Titmus Optical, Inc., Petersburg, VA) :j:True Visual Acuity (InnoMed Corp., Brea, CAl §Vistech Consultants, Inc. (Dayton, OH)
including ease of use, speed of testing, ease of patient understanding, low cost, portability, and scientific validity (Table 6). Most users maintained that these tests did not affect their surgical volumes (Table 7). Among users of these tests, 76% believed there definitely was or possibly was potential for abuse to justify unnecessary surgery. Most respondents who used these tests
indicated they did not bill separately for these procedures. Among users of these tests, the major criticism was the lack of standardization. Fewer criticized the lack of scientific validity, difficulty for physicians and their patients to interpret the tests, time required to administer the tests, cost, and poor correlation with symptoms (Table 8). Among those who did not use them, the major criticisms were lack of standardization, lack of familiarity with the tests, lack of scientific validity, superfluity of the tests, cost, and lack of correlation with symptoms. A plurality (42%) of respondents had a surgical volume of 11 to 25 cases per month, with approximately 20% having volumes of 0 to 10, 26 to 50, and more than 50 (Table 9).
Table 6. Reasons for selecting device.
Glare
Contrast Sensitivity
Ease of use
72%
57%
Speed of testing
67%
45%
Patient understanding
58%
47%
Low cost
50%
34%
Portability
49%
18%
Scientific validity
42%
52%
DISCUSSION
Table 7. Surgeons' attitudes toward glare and contrast sensitivity testing. Altered surgical volume Increased
14%
Decreased
1%
No change
85%
Potential for abuse to justify unnecessary surgery Definite potential
35%
Possible potential
41 %
No potential Unsure
5% 19%
Percentage of users billing for tests Glare
35%
Contrast sensitivity
40%
J CATARACT REFRACT
We recognize that there are limitations to a survey of this nature. 3 Multiple-choice questions limit the range of responses and presumably bias responses in specific directions. Since the confidentiality of the respondents was maintained, we could not resurvey those who did not respond to determine how they might differ from those who did. We nevertheless believe that our results provide important information on trends in vision testing. This survey points out the widespread use of glare and contrast sensitivity testing by cataract surgeons prior to the imposition of surgical precertification requirements by peer review organizations. Sixtyfive percent (65%) of our respondents indicated that they used glare and/or contrast sensitivity testing to supplement Snellen acuity testing (Table 1). Although the majority of those using these tests indicated that Snellen acuity was still the most effective means of assessing visual function, 77% and 41 % indicated that, in selected patients, glare and contrast sensitivity testing, respectively, served as the "final arbiter" in determining whether to proceed with surgery (Table 3). For many ophthalmolo-
SURG-VOL 16, NOVEMBER 1990
709
Table 8. Respondents' criticisms of glare and contrast sensitivity testing.
Table 9. Surgical volume of respondents. Cases Per Month
Glare Users Nonusers Lack of standardization Lack of scientific validity
44%
45%
Contrast Sensitivity Users Nonusers 55%
31%
19%
31%
21%
21%
Hard to interpret by physician
9%
32%
21%
13%
Time to administer test
7%
11%
19%
14%
Hard to interpret by patient
3%
10%
13%
11%
Cost
8%
30%
15%
20%
Lack of correlation with symptoms
6%
18%
11%
16%
Lack of familiarity with test
2%
37%
5%
28%
Superfluous
2%
32%
6%
20%
gists, therefore, these tests have become an integral part of their practices. The respondents indicated that they used glare testing primarily to evaluate patients with anterior segment disorders. Contrast sensitivity testing was used for anterior segment problems as well as for the evaluation of retinal and optic nerve diseases. These uses are consistent with our understanding of these tests. 1 ,2 Glare is caused by intraocular light scattering, and hence glare testing is likely to be more specific in evaluating anterior segment media opacities. Contrast sensitivity loss can be induced by a wide variety of disorders involving the anterior and posterior segments. Users of these tests indicated that they selected their particular devices for pragmatic and scientific reasons. Indeed, the responses in Table 6 could be interpreted as suggesting that practical reasons superseded scientific ones. However, the majority of users seemed to accept the scientific validity of these devices (see Tables 3 and 8); this presumably enabled them to select the particular devices best suited to their practice needs. The major criticism of these tests among users and nonusers was lack of standardization. Nonusers were more critical of the lack of scientific validity, high cost, and actual need for these tests, although approximately 33% of them indicated that one 710
Percentage
0-10
19
11-25
42
26-50
21
>
18
50
reason for not using them was their lack of familiarity with the tests. The results of this survey indicate that controversy about the uses and potential abuses of glare and contrast sensitivity testing exists. Many respondents indicated that these tests help them evaluate their patients' complaints better. Many of the nonusers criticized the tests as being superfluous. There was widespread concern about the potential for abuse of these tests to justify unnecessary surgery. Such potential unfortunately exists even for Snellen acuity. A drop in visual acuity to 20/80 could be used to justify surgery, whereas in most instances the determining factor should be the patient's perception of how severely his or her lifestyle is hampered by the cataract-induced visual loss. It is not surprising that ophthalmologists perceive glare and contrast sensitivity testing to be vulnerable to this same type of abuse. At the conclusion of the questionnaire, we asked the respondents to provide additional comments; nine did so. The contrasting views are well represented by these two comments: "I definitely believe that these acuity tests are true representations of patients' functional acuity, and patients should be strongly informed that they [the patients] may be a hazard to their and the public's safety." "The patient's symptoms, rather than any acuity test or equivalent, are the most important determinants for the need for surgery. As you know, when a cataract prevents a patient from satisfactorily enjoying his lifestyle, then surgery should be considered." Reflecting on the guidelines that were soon to be imposed in many states by peer review organizations, another respondent stated: "I hated to have the patient pay for testing which I found gave no different results than could be easily predicted by the other portions of the regular exam using clinical judgment and experience. I am aware that these tests are more sensitive than Snellen acuity and that I will soon have to do them for medicolegal and insurance
J CATARACT REFRACT SURG- VOL
16, NOVEMBER 1990
reasons - and I will do so at that time and play the game." Undoubtedly, multiple factors will determine the evolution of the use of various vision tests in ophthalmologists' practices. Perhaps the most optimistic finding in our survey is ophthalmologists' growing interest in vision testing and their willingness to explore new methods for more accurately assessing their patients' visual function.
REFERENCES 1. Koch DD. Glare and contrast sensitivity for the clinician. Ophthalmol Clin No Am 1989; 2:415-429 2. American Academy of Ophthalmology. Ophthalmic procedures assessment: Contrast sensitivity and glare testing in the evaluation of anterior segment disease. Ophthalmology 1990; 97:1233-1237 3. Learning DV Practice styles and preferences of ASCRS members-1988 survey. J Cataract Refract Surg 1989; 15: 689-697
J CATARACT REFRACT SURG- VOL
16, NOVEMBER 1990
711
ABSTRACT In August 1988, we surveyed a random 10% sample of the members of the American Society of Cataract and Refractive Surgery about their use of contrast sensitivity and glare testing. Of 396 surveys mailed, 214 were returned for a response rate of 54.3%. Thirty-six percent of respondents used glare testing alone; 5.6% used contrast sensitivity testing alone; 23.4% used both test modalities; 35% used neither. The most common uses of glare and contrast sensitivity testing were to evaluate visual function in patients who have cataracts, secondary cataracts, and/or intraocular lens problems.
Key Words: cataract evaluation, contrast sensitivity testing, glare testing, Snellen acuity
The limitations of Snellen acuity testing in assessing visual function have stimulated the development of new modes of visual testing. In particular, glare and contrast sensitivity testing provide important information about visual function that can supplement Snellen acuity readings. 1 ,2 These tests are potentially of greatest importance for patients who have relatively good Snellen acuities yet complain of significant visual disability. Because of advances in surgical techniques, such patients are often candidates for surgery. There are therefore obvious scientific, medicolegal, and, more recently, regulatory reasons for fully documenting their degree of visual disability. We wished to determine how extensively glare and contrast sensitivity testing were used by ophthalmologists with a known interest in cataract surgery. We conducted this survey prior to the imposition of guidelines for cataract surgery by the state peer review organizations (PRO), thereby eliminating the effect of external regulatory requirements on usage.
MATERIALS AND METHODS In the summer of 1988, we sent a 15-question survey to 396 American ophthalmologists, selecting every tenth name on the alphabetical membership list of the American Society of Cataract and Refractive Surgery. We selected this sample size to maximize our accuracy in determining the percentage of members using glare and/or contrast sensitivity in their practices. We assumed that 50% to 75% of the members used one or more of these tests. Our sample size of 396 members gave an alpha error of 0.025 for a minimum error of 0.05 at a usage level of 65% to 70%. This means that there was only one chance in 40 of having a greater than 5% error in determining the actual level of usage among those surveyed. To maintain strict confidentiality, the questionnaires and return envelopes were not marked or labeled. All questions were multiple choice; some required only one answer and others permitted a selection of several answers. The questions solicited information on the respondents' reasons for using or
From the Cullen Eye Institute, Houston, Texas (Koch), and Waco Eye Associates, Waco, Texas (Liu). Reprint requests to Douglas D. Koch, M.D., 6501 Fannin NC-200, Houston, Texas 77030.
J CATARACT REFRACT SURC-VOL 16, NOVEMBER 1990
707
Table 1. Incidence of glare and contrast sensitivity testing. U sed neither
35.0%
Table 2. Indications for glare and contrast sensitivity testing.
Indications
Glare
Contrast Sensitivity
Cataracts
98%
94%
U sed one or both
65.0%
Used both
23.4%
U sed glare only
36.0%
Secondary cataracts
62%
63%
Total glare use*
59.4%
Intraocular lens problems
28%
35%
Used contrast only
5.6%
Corneal problems
17%
19%
9%
27%
Optic nerve diseases
8%
31%
Glaucoma
0
31%
Total contrast use*
Retinal diseases
29.0%
*Includes the 23.4% who used both
not using glare and contrast sensitivity testing, the indications for their use, the preferred devices, advantages and disadvantages of these tests, and the impact of these tests on their practices. Responses were coded, entered into a computer database, and analyzed using the Statistical Analysis System (SAS) on an IBM-compatible computer. RESULTS We received responses from 214 of the 396 surveyed-54.3%. Sixty-five percent (65%) used contrast sensitivity and/or glare testing in their practices (Table 1); 59.4% used glare testing, and 29% used contrast sensitivity testing. The most frequent indication for glare testing was cataract evaluation, followed by secondary cataracts, intraocular lens evaluation, and corneal problems (Table 2). The primary indications for contrast sensitivity testing were similar, although a higher percentage of respondents also used contrast sensitivity to evaluate glaucoma, optic nerve diseases, and retinal diseases. The respondents indicated they used these tests primarily on cataract patients to assess visual function more accurately (Table 3). Other reasons included enhancing patient understanding and medicolegal factors. Respondents were evenly split in their selection of cataract patients on whom these tests were used. Approximately 50% used them on all patients complaining of glare regardless of Snellen acuities, whereas the other half used them only on patients who complained of glare despite having good Snellen acuities (Table 3). Seventy-seven percent (77%) of those using glare testing and 41 % of those using contrast sensitivity testing indicated that, in selected patients, these tests served as a final arbiter in determining the need for surgery (Table 3). Among users of these tests, the great majority indicated that Snellen acuity was the most accurate 708
J CATARACT REFRACT
means of assessing visual function in cataract patients (Table 4). Contrast sensitivity testing was felt to be the least effective by slightly more than 50% of this group. By far the most popular glare tester was the Brightness Acuity Tester (BAT), followed by the Miller Nadler Glare Tester, and the True Visual Acuity (TVA). The most popular contrast sensitivity system was the VCTS charts (Vis tech Corp.), with smaller numbers using the TVA and various other systems (Table 5). Respondents gave several reasons for selecting particular glare and contrast sensitivity devices,
Table 3. Use of tests in cataract patients. Glare
Contrast Sensitivity
Reasons for use Accurate visual function assessment
95%
84%
Patient understanding
65%
58%
Medicolegal
41%
21%
4%
11%
48%
52%
50%
40%
Marketing Patient status All patients with glare regardless of Snellen acuity Only patients with good Snellen acuity and glare All patients with good Snellen acuity regardless of visual complaints All patients Use in selected patients as arbiter to determine need for surgery
SURG-VOL 16, NOVEMBER 1990
6%
7%
19%
23%
77%
41%
Table 4. Users' ranking of effectiveness of visual function tests in cataract patients. Most*
Least*
Snellen acuity
73%
18%
Contrast sensitivity
19%
56%
Glare
14%
21%
Table 5. Devices used. Glare
Contrast Sensitivity
BAT*
65%
Vis tech charts§
Miller Nadlert
24%
TVA
16%
TVA:j:
13%
Other
11%
Other
8%
79%
*The percentages in these columns do not add up to 100% because some responders ranked more than one test as most or least effective.
*Brightness Acuity Tester (Mentor 0 & 0, Inc., Norwell, MA) tMiller Nadler Glare Tester (Titmus Optical, Inc., Petersburg, VA) :j:True Visual Acuity (InnoMed Corp., Brea, CAl §Vistech Consultants, Inc. (Dayton, OH)
including ease of use, speed of testing, ease of patient understanding, low cost, portability, and scientific validity (Table 6). Most users maintained that these tests did not affect their surgical volumes (Table 7). Among users of these tests, 76% believed there definitely was or possibly was potential for abuse to justify unnecessary surgery. Most respondents who used these tests
indicated they did not bill separately for these procedures. Among users of these tests, the major criticism was the lack of standardization. Fewer criticized the lack of scientific validity, difficulty for physicians and their patients to interpret the tests, time required to administer the tests, cost, and poor correlation with symptoms (Table 8). Among those who did not use them, the major criticisms were lack of standardization, lack of familiarity with the tests, lack of scientific validity, superfluity of the tests, cost, and lack of correlation with symptoms. A plurality (42%) of respondents had a surgical volume of 11 to 25 cases per month, with approximately 20% having volumes of 0 to 10, 26 to 50, and more than 50 (Table 9).
Table 6. Reasons for selecting device.
Glare
Contrast Sensitivity
Ease of use
72%
57%
Speed of testing
67%
45%
Patient understanding
58%
47%
Low cost
50%
34%
Portability
49%
18%
Scientific validity
42%
52%
DISCUSSION
Table 7. Surgeons' attitudes toward glare and contrast sensitivity testing. Altered surgical volume Increased
14%
Decreased
1%
No change
85%
Potential for abuse to justify unnecessary surgery Definite potential
35%
Possible potential
41 %
No potential Unsure
5% 19%
Percentage of users billing for tests Glare
35%
Contrast sensitivity
40%
J CATARACT REFRACT
We recognize that there are limitations to a survey of this nature. 3 Multiple-choice questions limit the range of responses and presumably bias responses in specific directions. Since the confidentiality of the respondents was maintained, we could not resurvey those who did not respond to determine how they might differ from those who did. We nevertheless believe that our results provide important information on trends in vision testing. This survey points out the widespread use of glare and contrast sensitivity testing by cataract surgeons prior to the imposition of surgical precertification requirements by peer review organizations. Sixtyfive percent (65%) of our respondents indicated that they used glare and/or contrast sensitivity testing to supplement Snellen acuity testing (Table 1). Although the majority of those using these tests indicated that Snellen acuity was still the most effective means of assessing visual function, 77% and 41 % indicated that, in selected patients, glare and contrast sensitivity testing, respectively, served as the "final arbiter" in determining whether to proceed with surgery (Table 3). For many ophthalmolo-
SURG-VOL 16, NOVEMBER 1990
709
Table 8. Respondents' criticisms of glare and contrast sensitivity testing.
Table 9. Surgical volume of respondents. Cases Per Month
Glare Users Nonusers Lack of standardization Lack of scientific validity
44%
45%
Contrast Sensitivity Users Nonusers 55%
31%
19%
31%
21%
21%
Hard to interpret by physician
9%
32%
21%
13%
Time to administer test
7%
11%
19%
14%
Hard to interpret by patient
3%
10%
13%
11%
Cost
8%
30%
15%
20%
Lack of correlation with symptoms
6%
18%
11%
16%
Lack of familiarity with test
2%
37%
5%
28%
Superfluous
2%
32%
6%
20%
gists, therefore, these tests have become an integral part of their practices. The respondents indicated that they used glare testing primarily to evaluate patients with anterior segment disorders. Contrast sensitivity testing was used for anterior segment problems as well as for the evaluation of retinal and optic nerve diseases. These uses are consistent with our understanding of these tests. 1 ,2 Glare is caused by intraocular light scattering, and hence glare testing is likely to be more specific in evaluating anterior segment media opacities. Contrast sensitivity loss can be induced by a wide variety of disorders involving the anterior and posterior segments. Users of these tests indicated that they selected their particular devices for pragmatic and scientific reasons. Indeed, the responses in Table 6 could be interpreted as suggesting that practical reasons superseded scientific ones. However, the majority of users seemed to accept the scientific validity of these devices (see Tables 3 and 8); this presumably enabled them to select the particular devices best suited to their practice needs. The major criticism of these tests among users and nonusers was lack of standardization. Nonusers were more critical of the lack of scientific validity, high cost, and actual need for these tests, although approximately 33% of them indicated that one 710
Percentage
0-10
19
11-25
42
26-50
21
>
18
50
reason for not using them was their lack of familiarity with the tests. The results of this survey indicate that controversy about the uses and potential abuses of glare and contrast sensitivity testing exists. Many respondents indicated that these tests help them evaluate their patients' complaints better. Many of the nonusers criticized the tests as being superfluous. There was widespread concern about the potential for abuse of these tests to justify unnecessary surgery. Such potential unfortunately exists even for Snellen acuity. A drop in visual acuity to 20/80 could be used to justify surgery, whereas in most instances the determining factor should be the patient's perception of how severely his or her lifestyle is hampered by the cataract-induced visual loss. It is not surprising that ophthalmologists perceive glare and contrast sensitivity testing to be vulnerable to this same type of abuse. At the conclusion of the questionnaire, we asked the respondents to provide additional comments; nine did so. The contrasting views are well represented by these two comments: "I definitely believe that these acuity tests are true representations of patients' functional acuity, and patients should be strongly informed that they [the patients] may be a hazard to their and the public's safety." "The patient's symptoms, rather than any acuity test or equivalent, are the most important determinants for the need for surgery. As you know, when a cataract prevents a patient from satisfactorily enjoying his lifestyle, then surgery should be considered." Reflecting on the guidelines that were soon to be imposed in many states by peer review organizations, another respondent stated: "I hated to have the patient pay for testing which I found gave no different results than could be easily predicted by the other portions of the regular exam using clinical judgment and experience. I am aware that these tests are more sensitive than Snellen acuity and that I will soon have to do them for medicolegal and insurance
J CATARACT REFRACT SURG- VOL
16, NOVEMBER 1990
reasons - and I will do so at that time and play the game." Undoubtedly, multiple factors will determine the evolution of the use of various vision tests in ophthalmologists' practices. Perhaps the most optimistic finding in our survey is ophthalmologists' growing interest in vision testing and their willingness to explore new methods for more accurately assessing their patients' visual function.
REFERENCES 1. Koch DD. Glare and contrast sensitivity for the clinician. Ophthalmol Clin No Am 1989; 2:415-429 2. American Academy of Ophthalmology. Ophthalmic procedures assessment: Contrast sensitivity and glare testing in the evaluation of anterior segment disease. Ophthalmology 1990; 97:1233-1237 3. Learning DV Practice styles and preferences of ASCRS members-1988 survey. J Cataract Refract Surg 1989; 15: 689-697
J CATARACT REFRACT SURG- VOL
16, NOVEMBER 1990
711
