Essential Outcomes Measures are not Acuity, Visual Field and Pressure but rather Performance (AFREV) and Quality of Life

MB Sherwood
University of Florida

The World Health Organization (WHO) defines Quality of Life (Q of L) as “an individual’s perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards and concerns”.

Glaucoma may affect Q of L in several ways. These include the visual effects of the disease itself (decreased visual field and ultimately VA), the psychological effects of diagnosis (specifically fear of blindness), the potential side effects of treatment (either medical or surgical) and financial effects (namely the cost of visits and therapy).

There are important patient-centered clinical questions, which need to be asked, related to glaucoma care. These include “what degree of nerve fiber layer or visual field loss is required for patients to detect a deterioration in their visual function or quality of life?” and “what is the likelihood and time course of the deterioration for that individual patient?”

Success in glaucoma management may be defined from various different viewpoints. An Ophthalmologists’ perspective is likely to be centered around visual field and visual acuity stability, nerve fiber layer and optic disc stability, achieving target IOP and possibly side effects of therapy. Patient or family perspective may be centered more strongly around visual function, task performance, financial limitations and concerns or fears for the future. With reference to the last patient perspective issue, Odberg et al published reported the results of a self-adminstered questionnaire by 589 patents, in which more than 80% reported negative emotions on learning that they had glaucoma. One-third were afraid of going blind. Nine-tenths of the individuals were satisfied with the information and care given, although their knowledge about glaucoma was incomplete and one-fifth missed information, mainly on causes, treatment and prognosis of the disease 1.Other perspectives to be considered when gauging the success of glaucoma care include those of the health care administrator and society in general.

It is easy to measure IOP or even follow a visual field or disc morphology looking for deterioration but it is a harder to scientifically science quantitate the patients’ subjective experience of his or her eye disease and convert that into a numeric score which best shows consistency and can be used to track progression.

Most evaluations of the patients’ perspective of their disease, center around the use of questionnaires. These fall into 2 broad groups; those that are self-administered and those in which the questionnaire is administered by a trained technician either directly or by telephone. Any Q of L questionnaire needs to be validated by a study to confirm its ability to show differences between patients with the disease and normals, and also be able to confirm repeatability and reliability. Most Q of L questionnaires or “instruments” use a scale (eg 0-5 or none, mild, moderate, severe) for patients to describe their response to a question and the overall numeric score is created by summing these numbers for a particular category or domain (such as pain, eating, work etc). Some questionnaires attempt to ask open-ended questions but the answers can be difficult to quantify. Care must be taken, as with visual field testing, not to make the tests too long so that patient concentration and willingness to answer remains high.

Numerous Q of L instruments have been described and evaluated for many different diseases. These fall into 3 main categories;

1) General Quality of Life Instruments which assess the interaction of the disease with the performance of daily life tasks. These include the Medical Outcomes Study (MOS SF-20 & SF-36) which examines 8 parameters (physical functioning, limitations due to physical and emotional problems, social functioning, pain, mental health, vitality and health perceptions). MOS showed patients with glaucoma to have lower scores and those with suspected glaucoma to have intermediate scores 2 .Q of L perception was shown to differ between patients with glaucoma and control subjects when scored using MOS-20 and increasing field loss, decreased visual acuity and complexity of therapy correlated with patents’ reduction in activities of daily vision (scale) (ADVS) 3. Lee et al in 1997 found that “having blurred vision more than once or twice a month had a detectable and significant impact on functional status and well-being” as measured by the SF-36 4. Iester et al reported that Viswanathan et al’s questionnaire was more useful than MOS SF-36 and was more significantly correlated with visual field MD 5.

The Sickness Impact Profile (SIP) uses12 subscales (sleep and rest, eating, work, home management, recreation and pastimes, ambulation, mobility, body care and movement, social interaction, alertness behavior, emotional behavior and communication) to evaluate Q of L.

2) Visual Quality of Life Instruments assess visual functioning related to task performance. The NEI - Visual Functioning Questionnaire (NEI – VFQ) was shown to be reliable and valid for group-level comparisons of health-related Q of L in clinical research 6.

Gutierrez et al found that vision-targeted questionnaires were more sensitive than a generic health-related Q of L measure, to differentiate between glaucomatous and normal reference participants 7. Their findings also indicated that self-reports of vision-targeted health-related Q of L are sensitive to visual field loss and may be useful in tandem with the clinical examination to fully understand outcomes of treatment for glaucoma.

Parrish et al found a weak correlation between visual field impairment, visual functioning and global quality of life with (MOS) 36 scores and a moderate correlation with NEI-VFQ and VF-14 scores 8.

Broman et al used the NEI-VFQ questionnaire to show that subjects with uncorrected refractive error, cataract, diabetic retinopathy, and glaucoma had associated decrements in quality of life, many not explained by loss of acuity 9.

Jampel found that both FVQ and SF-36 correlated only moderately with the Esterman binocular field test and other visual function tests and that A global score derived from a combination of two monocular fields correlated better with patient assessment of vision than did the Esterman and four novel binocular visual field tests 10 11.

The Glaucoma Symptom Scale (GSS), discriminated well between persons with and without glaucoma 12.

Wandell et al used the Health-Related quality of life (HRQOL) in 270 glaucoma patients to indicate that health related quality of life in glaucoma patients in general is good, especially when vision is intact 13.

Nelson et al used questionnaire responses (vision-related quality of life, general health and psychosocial variables), visual acuity, visual fields, Esterman binocular disability scores, contrast sensitivity, critical flicker frequency, color vision, dark adaptation, glare disability (brightness acuity), and stereoacuity scores to explore patients self-reported visual disability resulting from glaucoma. 15 of the 50 questions were noted to have a strong significant relationship with a measure of visual field loss and were included in a new questionnaire scale, the Glaucoma Quality of Life - 15 (GQL-15) 14.

Simmons et al used the Glaucoma Disability Index to assess patients’ quality of life as part of their protocol comparing adjunctive glaucoma medications 15 and Montemayor et al used the Visual Function Assessment and EQ-5D questioners to evaluate visual function and quality of life in patients receiving multiple glaucoma medications 16. Their results suggested that the number of glaucoma medications was not predictive of quality of life.

Five-year result for the Collaborative Initial Glaucoma Treatment Study (CIGTS) indicate similar outcomes as well as Q of L impact reported by the two treatment groups 17 18 19. The quality of life testing in this study included a Visual Activities Questionnaire (VAQ), Sickness Impact Profile (SIP), a symptom and a co-morbidity chart, a question about the degree of fear of becoming blind and many other items.

3) Medication Tolerability Instruments;
Comparison of Ophthalmic Medication For Tolerability (COMTOL).

The need for objective testing of Q of L beyond a pateints’ subjective response to a questionnaire is obviously desirable. Efforts to achieve this goal are underway.

A recent study by Undraa et al, the “Assessment of Function Related to Vision” (AFREV), was designed to investigate the use of a single instrument to assess actual functional ability of people with various eye conditions. In a prospective study, 43 glaucoma patients were evaluated using a standard ophthalmic examination, Lighthouse ETDRS, Pelli-Robson contrast sensitivity, Esterman Binocular simultaneous visual field testing (Humphrey Field Analyser, Program 24-2). Each study patient completed the interviewer-administered version of the National Eye Institute Visual Functioning Questionnaire (NEIVFQ-25). In addition, a trained examiner measured the accuracy of the testee’s performance on a battery of standardized tasks such as “putting stick into holes,” “phone dialing,” “using a calculator,” “lock opening,” “box finding,” “coin finding” and “mobility” tasks. The tests were scored in terms of a standardized assessment for each specific task.

The strongest correlations were between the AFREV total score and contrast sensitivity, binocular visual acuity, better-eye visual acuity, and worse-eye visual acuity. The Esterman efficiency score was strongly correlated with the AFREV summary performance score. The NEI-VFQ total score showed strong correlations with the worse-eye visual acuity, contrast sensitivity and the Esterman score. It was concluded that differences exist between assessment of function using isolated tests (visual acuity, visual field, contrast sensitivity, etc), self-reported assessment (NEI-VFQ, SF-36, Sickness Impact Profile, etc.) and measures of actual performance of tasks of daily living. The vision tests that appeared to correlate best with performance-based measures were contrast sensitivity, binocular visual acuity and Esterman binocular visual field test and there is a poor correlation between the AMA Disability Index and estimates of self- assessment and actual visual performance 20 21 22 23.

In summary, it is helpful for ophthalmologists to have a clear concept of how glaucoma affects the everyday activities and Q of L of their patients. New tools to assess these parameters are important in our efforts to achieve optimal glaucoma care.

References

1 Odberg T, Jakobsen JE, Hultgren SJ, Halseide R. The impact of glaucoma on the quality of life of patients in Norway. I. Results from a self-administered questionnaire. Acta Ophthalmol Scand. 2001 Apr;79(2):116-20.

2 Wilson MR, Coleman AL, Yu F, Bing EG, Sasaki IF, Berlin K, Winters J, Lai A. Functional status and well-being in patients with glaucoma as measured by the Medical Outcomes Study Short Form-36 questionnaire. Ophthalmology. 1998 Nov;105(11):2112-6.

3 Sherwood MB, Garcia-Siekavizza A, Meltzer MI, Hebert A, Burns AF, McGorray S. Glaucoma's impact on quality of life and its relation to clinical indicators. A pilot study. Ophthalmology. 1998 Mar;105(3):561-6.

4 Lee PP, Spritzer K, Hays RD. The impact of blurred vision on functioning and well-being. Ophthalmology. 1997 Mar;104(3):390-6.

5 Iester M, Zingirian M. Quality of life in patients with early, moderate and advanced glaucoma. Eye. 2002 Jan;16(1):44-9.

6 Mangione CM, Lee PP, Pitts J, Gutierrez P, Berry S, Hays RD. Psychometric properties of the National Eye Institute Visual Function Questionnaire (NEI-VFQ). NEI-VFQ Field Test Investigators. Arch Ophthalmol. 1998 Nov;116(11):1496-504.

7 Gutierrez P, Wilson MR, Johnson C, Gordon M, Cioffi GA, Ritch R, Sherwood M, Meng K, Mangione CM. Influence of glaucomatous visual field loss on health-related quality of life. Arch Ophthalmol. 1997 Jun;115(6):777-84.

8 Parrish RK 2nd, Gedde SJ, Scott IU, Feuer WJ, Schiffman JC, Mangione CM, Montenegro-Piniella A. Visual function and quality of life among patients with glaucoma. Arch Ophthalmol. 1997 Nov;115(11):1447-55.

9 Broman AT, Munoz B, Rodriguez J, Sanchez R, Quigley HA, Klein R, Snyder R, West SK. The impact of visual impairment and eye disease on vision-related quality of life in a Mexican-American population: proyecto VER. Invest Ophthalmol Vis Sci. 2002 Nov;43(11):3393-8

10 Jampel HD. Glaucoma patients' assessment of their visual function and quality of life. Trans Am Ophthalmol Soc. 2001;99:301-17.

11 Jampel HD, Friedman DS, Quigley H, Miller R. Correlation of the binocular visual field with patient assessment of vision. Invest Ophthalmol Vis Sci. 2002 Apr;43(4):1059-67.

12 Lee BL, Gutierrez P, Gordon M, Wilson MR, Cioffi GA, Ritch R, Sherwood M, Mangione CM. The Glaucoma Symptom Scale. A brief index of glaucoma-specific symptoms. Arch Ophthalmol. 1998 Jul;116(7):861-6.

13 Wandell PE, Lundstrom M, Brorsson B, Aberg H. Quality of life among patients with glaucoma in Sweden. Acta Ophthalmol Scand. 1997 Oct;75(5):584-8.

14 Nelson P, Aspinall P, Papasouliotis O, Worton B, O'Brien C. Quality of life in glaucoma and its relationship with visual function. J Glaucoma. 2003 Apr;12(2):139-50.

15 Simmons ST, Earl ML; Alphagan/Xalatan Study Group. Three-month comparison of brimonidine and latanoprost as adjunctive therapy in glaucoma and ocular hypertension patients uncontrolled on beta-blockers: tolerance and peak intraocular pressure lowering. Ophthalmology. 2002 Feb;109(2):307-14; discussion 314-5.

16 Montemayor F, Sibley LM, Courtright P, Mikelberg FS. Contribution of multiple glaucoma medications to visual function and quality of life in patients with glaucoma. Can J Ophthalmol. 2001 Dec;36(7):385-90.

17 Mills RP. Correlation of quality of life with clinical symptoms and signs at the time of glaucoma diagnosis. Trans Am Ophthalmol Soc. 1998;96:753-812.

18 Mills RP, Janz NK, Wren PA, Guire KE. Correlation of visual field with quality-of-life measures at diagnosis in the Collaborative Initial Glaucoma Treatment Study (CIGTS). J Glaucoma. 2001 Jun;10(3):192-8.

19 Janz NK, Wren PA, Lichter PR, Musch DC, Gillespie BW, Guire KE, Mills RP; CIGTS Study Group. The Collaborative Initial Glaucoma Treatment Study: interim quality of life findings after initial medical or surgical treatment of glaucoma. Ophthalmology. 2001 Nov;108(11):1954-65.

20 Turano KA, Rubin GS, Quigley HA. Mobility performance in glaucoma. Invest Ophthalmol Vis Sci 1999;40(12):2803-9.

21 Guralnik JM, Simonsick EM, Ferrucci L. A short physical performance battery assessing lower extremity function: association with self-reported disability and prediction of mortality and nursing home admission. Medical Sciences 1994;49(2):M85-M94.

22 Szlyk JP, Seiple W, Fishman GA, et al. Perceived and actual performance of daily tasks: relationship to visual function tests in individuals with retinitis pigmentosa. Ophthalmology 2001;108(1):65-75.

23 Jampel HD. Glaucoma Patient's Assessment of their Visual Function and Quality of Life. Trans Am Ophthalmol Soc 2001;99:301-17