Usability of the Software MacuFix for the Categorization of Metamorphopsia and Evaluation of Patient Adherence Compared to the Amsler Grid
Conditions: Vision Disorders
Sponsor: Augenheilkunde Lindenthal

Usability of the software MacuFix for the categorization of metamorphopsia 
and evaluation of patient adherence compared to the Amsler Grid 
 
ClinicalTrials.gov Identifier: NCT04347564 
 
21.04.2021 
 
 
Abstract 
Aim: Macular diseases can lead to metamorphopsia, which is traditionally tested 
using the standard functional test, Amsler grid.  The current study attempts to 
evaluate a new method to assess metamorphopsia, which is based on the software 
AMD-A Metamorphopsia Detector, the app MacuFix®. 
Methods: In this observational study, the usability of a new smartphone-based testing 
method to assess metamorphopsia was evaluated in 45 patients experiencing 
metamorphopsia in at least one eye using the questionnaire "System Usability Score 
(SUS)". Additionally, the diagnostic adherence of self-monitoring with the Amsler grid 
was compared to self-monitoring with the novel software MacuFix®.  
Results: The average score of the SUS questionnaire in this study was 76.7 
(SD=±15.5) corresponding to the score "excellent". The average interval between two 
home tests was significantly shorter when using the app MacuFix (6 days) compared 
to using the Amsler grid (19 days). Once the app was available, the odds ratio for 
persons previously not using a home test to imply the app as a home test was 4.5. 
Conclusion: MacuFix® application can help meet the unmet needs in home 
monitoring of macular function as high user satisfaction and increased testing 
frequency was observed with the use of MacuFix®. This may lead to improved 
outcomes in the treatment of macular disease. 
 
Key Words: 

Metamorphopsia, Usability, Adherence, Age-related macular degeneration  
Diabetic macular edema, Smartphone-based app 
 
Introduction 
Diseases of the macula can lead to metamorphopsia traditionally tested with the 
Amsler grid as the standard functional test.[1] Alternative tests are supposed to 
overcome its limitations.[2-6] A new method to assess metamorphopsia is based on 
the software AMD-A Metamorphopsia Detector®.[7,8] The MacuFix® test (app4eyes, 
developed by Ronald Krüger, patent DE 10 2019 205 318 A1) is available for use on 
a screen (PC, smartphone, tablet, iPad) both for Android and iOS platforms. This 
study determined the user-friendliness with the questionnaire "System Usability 
Score (SUS)" and compared the adherence of self-monitoring with the Amsler grid 
versus the software MacuFix®.[9,10]  
 
Materials and Methods 
For this observational pilot study 47 persons were recruited from the patient pool of 
an ophthalmologic group practice and subjected to the study examination as part of 
their medically necessary control examination. 
As early as October 2019, patients were informed about the planned study and that 
inclusion in the study could only take place after a positive vote of the ethics 
committee.  In the context of the Covid-19 pandemic, stakeholders recommended to 
reduce the number of follow up visits. Many of those interested in participating in the 
study asked for a home test as a supplement to conventional diagnostic tests such as 
Optical Coherence Tomography (OCT). For this reason, based on the approval of the 
competent ethics committee (No. 600213225), the decision was made to inform the 
participating persons about the possibility of using the App MacuFix® as a home test 

and to start a prospective, controlled study to examine the adherence using a self-
test. After a positive vote by the Ethics Committee of the North Rhine Medical 
Association (No. 2020057) on 1st April, 2020, in which the Ethics Committee stated 
that there were no professional ethical or legal objections to the study, patients who 
had expressed interest in participating in the study were informed about the study in 
writing. After signing informed consent 45 patients were included in the study from 4th 
May, 2020 – 30th June,2020. The study conformed to the tenets of the Declaration of 
Helsinki of 1975, as revised in 2013. 
Inclusion criteria 
Patients aged above 18 years of either gender with metamorphopsia (ICD Code H 
53.15) in at least one eye, detected with Amsler grid and a best-corrected visual 
acuity (BCVA) of at least 20/200 and consenting to participate in the study were 
enrolled.  
Exclusion Criteria 
Patients not fulfilling the inclusion criteria, advanced glaucoma and intraocular 
surgery other than cataract surgery or vitrectomy within prior 3 months could not 
participate in the study. 
Endpoints 
The primary endpoint investigated in the observational study was the score of the 
SUS questionnaire. The secondary endpoint investigated in the prospective, 
controlled interventional study arm was the frequency of use of the Amsler test or the 
app MacuFix® measured as the time interval in days between two measurements to 
assess test adherence. 
Examination procedure and period 
As part of a routine examination, each participating patient carried out the MacuFix 
test with each eye with adequate near correction once in the period 4th May, 2020 – 

30th June,2020. In addition, BCVA was measured, a retinal examination was 
performed and a spectral domain OCT (SD-OCT, CIRRUS ™ HD-OCT, Carl Zeiss 
Meditec) was performed. All study patients filled out the pseudonymised 
questionnaire SUS after performing the MacuFix® test. If they were interested, the 
patients were given a link for free use of MacuFix® as a home test on a PC for future 
use of the test. Alternatively, the patients could download the test as an app for use 
with an iPad or smartphone. The patients were asked whether they agreed to be 
interviewed about the frequency of the Amsler test and after three months about the 
frequency of using the app or the Amsler grid. 
On the study day, each patient was asked about the frequency of use of the Amsler 
test. The standardized question was: "I would like to know from you how often you 
have used the Amsler Grid in the past. The following question refers to the period 
from January 2020 to March 2020 (baseline period): How many days usually elapsed 
after a test with the Amsler Grid until the next test?” 
12-14 weeks after the study day, patients were contacted by telephone and asked 
about their testing behavior during the previous three months (comparison period). 
The standardized question was now: "I would like to ask you two questions about the 
Amsler Grid and the App Macufix®. With my question I would like to record how often 
you have carried out one of the two tests in the past three months. Did you use one 
of the two test methods?" The following question, if applicable was “How many days 
usually elapsed after a test with the method you chose until the next time you used 
this test method?”  
 
Explanation of the test procedure for the MacuFix® Test 
The interactive test shows on a PC screen four square fields with a grid pattern of 
horizontal and vertical lines. All four fields have lines that are partially distorted 

(wavy). However, one of the four squares differ from the remaining three squares by 
more strongly distorted lines (see Figure 1). The difference between this grid pattern 
and the remaining three can be noticeable or small. The task of the test patient is to 
select this more distorted field when viewing with one eye wearing appropriate near 
correction. The selection can be made by pointing or a verbal message for an 
assistant or by tapping on the touch screen. This selection must be made at least  10 
times per eye to reach a result: an algorithm determines the smallest distortion 
difference that was correctly named in at least 80%. This is given as a class, where 
class 1 stands for the smallest distortion difference offered, i.e. the best result. The 
procedure takes about 2 minutes per eye. Encrypted results can be sent to the 
ophthalmologist via email. Afterwards the other eye is tested in the same way. All 
data remain on the device during the MacuFix® test. The test was developed in 
accordance with the German data protection regulations (DSGVO). 
 
Fig. 1 MacuFix® Test on a mobile device 
 
System Usability Scale (SUS) Questionnaire  
The SUS questionnaire was developed to determine how users perceive the ease of 
use of a software.[10] It consists of ten statements based on Likert scale, each with 

five possible answers ranging from complete rejection to complete agreement. The 
SUS questionnaire contains five positive and five negative statements about the 
usability of the system to be evaluated. Thus, data is collected which can be 
quantitatively evaluated and interpreted, the result is a percentage usability value of 
the application. The SUS questionnaire contains the following ten statements: 
- I can well imagine using the test regularly. 
- I find the test unnecessarily complicated. 
- I find the test easy to use. 
- I think I would need technical support to use the test. 
- I find that the various functions of the test are easy to use. 
- I think that there are too many inconsistencies in the test. 
- I can imagine that most people learn to master the test quickly. 
- I find the operation very complicated. 
- I have felt very confident in using the test. 
- I had to learn a lot of things before I could work with the test. 
 
For each statement the participant gives his agreement or disagreement in the form 
of a scale ranging from 1= strong agreement to 5= strong disagreement. The results 
of the SUS questionnaire are used to calculate a numerical value (the SUS score). 
The categories in the SUS questionnaire are coded with values from 0 to 4. The 
coding depends on the formulation: If the answer is positive, the answer will be coded 
as 4 for full agreement and 0 for a complete rejection. If the answer is negative, the 
answer will be coded as 0 for full agreement and 4 for a complete rejection. The 
numbers obtained in the 10 questions are added together - the sum is between 0 and 
40 - and then multiplied by 2.5. For example, if the sum of all answers is 22, the SUS 

score is 55. The results of the SUS questionnaire range from 0 (worst score) to 100 
(best score). 
 
Survey on test frequency 
As part of the study investigation on the study day, the study participants were asked 
how many days had usually elapsed between two Amsler grid tests in the baseline 
period. The response spectrum could range from "1" for daily performance to "90" for 
a maximum of once in three months. 12-14 weeks after the study day, the study 
participants were called and asked how many days elapsed between the 
performance of two self-tests in the previous 3 months (comparison period). 
 
Statistical Analysis 
Since the study had a primarily exploratory character, no a priory sample size was 
carried out. The study had two groups of patients, the group of patients who 
continued to use the Amsler test or no selftest after the study day (group “Stay”) and 
the group of patients who used the app MacuFix® after the study day (group 
“Switch”). 
 
Comparison "Stay" and "Switch" after the study day 
For the prospective, controlled study on adherence using a self-test, the null 
hypothesis was, there is no difference in the mean values of the two populations with 
respect to the frequency of use of the Amsler grid and the MacuFix® software 
(interindividual comparison using t-test for unrelated samples). The alternative 
hypothesis was, there is a difference in the mean values of the two populations. 
 

Intraindividual comparison of the test frequency before and after the study day in the 
"Stay" and "Switch" group 
The null hypothesis for the intraindividual comparison was: the frequency of use 
changed in the group of patients who stayed with the Amsler grid in the same way as 
those who switched to the MacuFix® test (intraindividual comparison using the t-test 
for paired samples). The alternative hypothesis was, the change in test frequency 
was different in the group of patients who stayed with the Amsler grid compared to 
those who switched to the MacuFix® test.  
 
Comparison of "Stay" and "Switch" before the study day 
In addition, the t-test for unrelated samples was used to compare whether the "Stay" 
group differed from the "Switch" group in the frequency of self-testing prior to the 
study day in order to rule out a selection bias. The statistical method used for this 
intraindividual comparison was the two-sided t-test for paired samples. 
All statistical analyses were performed with the statistical software "R" (Version 
3.6.1., R Foundation, R Core Team): A Language and environment for statistical 
computing. R Foundation for Statistical Computing, Vienna, Austria. http://www.R-
project.org). 
 
Results 
Composition of the investigated collective 
Of 75 patients questioned, 47 were willing to participate in the study. One patient 
withdrew her consent and one patient was unable to participate in the study due to 
the treatment of a glioblastoma, which had become apparent before the study day 
through a scotoma on the functionally single eye. The remaining 45 patients (18 
females, 27 males) completed the SUS questionnaire on the same day after the 

MacuFix® test had been performed and answered the question referring to the test 
frequency of the Amsler test in the baseline period.  Thirty-five study participants 
were interested in using the MacuFix® test as a home test after the study, three of 
them used a PC, one patient used an iPad and 31 used a smartphone. All subjects 
agreed to a telephone survey to be conducted later on the frequency of using a home 
test. 
The mean age was 68 ± 9.7 years (SD). The mean visual acuity was 20/30 (Snellen 
fraction) or 0.6 (decimal) respectively (SD=0.25). Of the 90 eyes, 18 eyes showed no 
abnormal macular findings. In 22 eyes, there was an early macular degeneration with 
small to medium sized drusen but no changes in the retinal pigment epithelium. 
Sixteen eyes showed intermediate age-related macular degeneration (AMD) with 
large drusen or at least medium-sized drusen associated with pigment epithelial 
changes. Fourteen eyes suffered from AMD (four geographic atrophy, ten 
neovascular AMD). In six cases, epiretinal gliosis or vitreo-macular traction was 
present. One eye showed a macular hole. Diabetic macular edema (DME) was 
present in both eyes of one patient. In one eye macular edema was due to retinal 
vein occlusion, in two eyes due to uveitis. Two eyes showed no edema after 
treatment for uveitic edema. Four eyes had developed Irvine Gass Syndrome 4-12 
weeks (average 7.5 weeks) after cataract surgery while two eyes had central serous 
chorioretinopathy. Of the 90 eyes of 45 study participants two eyes could not be 
measured with Macufix due to central scotoma caused by geographic atrophy. 
MacuFix measurements of 88 eyes were included. 
 
 
Sensitivity and Specificity of MacuFix to identify Metamorphopsia 

When examined with the Amsler Grid, 42 eyes perceived metamorphopsia, 46 did 
not see metamorphopsia. Referring to the Amsler Grid as a gold standard, MacuFix® 
measurements were correct positive in 38, false positive in four, correct negative in 
43 and false negative in three cases. This led to a sensitivity of the App MacuFix® of 
92.7% and a specificity of 91.5 %. 
 
Score SUS 
Average values of the individual questions in the SUS questionnaire are enlisted in 
Table 1. 0 corresponds to a negative and 4 to the best possible rating. The app 
received the best ratings in questions number 7,8,10 reflecting that the study 
participants experienced the test as easy to learn and uncomplicated. To illustrate the 
result of the SUS score, Bangor et al associated the SUS scores of 1000 
questionnaires with a scale of seven adjectives.[9] The scale contains adjectives such 
as "good," "ok," and "bad", that users loosely associated with the usability of a 
product. The authors found that ratings with a score above 85 were associated with 
"best possible". "Excellent" corresponded to ratings of 73-84 points, "good" was 
associated with ratings whose score was 63- 72 points. The rating "okay" correlated 
with score values from 52- 63 and the rating "poor" was associated with score values 
of 51 or less. The average score of the SUS questionnaire in this study was 76.7 
(SD=±15.5), which corresponds to the score "excellent".  
 
Choice of the test procedure 
Of 38 persons who used the Amsler test in the baseline period, eight persons 
continued using the Amsler grid in the comparison period (group “Stay”). The 
remaining 30 patients decided to use the MacuFix test instead of the Amsler test 
(group “Switch”). 

Seven of the 45 patients had not used any self-test to check for metamorphopsia in 
the baseline period. Two of them continued not to use a self-test in the three month 
comparison period after the study day. The remaining five patients used the 
MacuFix® app in the comparison period. None of these patients used the Amsler grid 
after the study day. 
 
Test Frequency 
The average interval between two Amsler tests was 22.5 days in the baseline period 
(SD = ±14.1; confidence interval (CI) = 18.1; 27.0). The average interval between two 
Amsler tests in the comparison period was 19.4 days (SD = ±10.8; CI = 11.9; 26.9). 
The average interval between performing two MacuFix tests after the study day was 
5.8 (SD = ±6.4; CI = 3.7; 7.9). 
 
Intra-individual comparison in the group that continuously used the Amsler test 
("Stay") 
In this group, the interval between two Amsler tests averaged 26 days in the baseline 
period from January to March 2020 and 19 days between two Amsler tests in the 
three month comparison period after the study day. In the group "Stay" the critical 
value is 2.365 with seven degrees of freedom and a probability of error (α) = 0.05. 
Since the test statistic of 1.697 is not higher than the critical value, the test frequency 
with the Amsler test in the baseline period did not differ significantly from the 
comparison period (t-test for paired samples: (|-1.697| < 2.365; p > 0.05; n = 8). 
 
Intraindividual comparison in the group that switched from the Amsler test to App 
MacuFix ("Switch") 

In this group the test frequency increased statistically significant after switching from 
Amsler grid to MacuFix. The time interval between two Amsler tests averaged 31 
days in the baseline period. In the comparison period the average interval between 
two MacuFix tests was 6 days. 
In the Switch group, the critical value is 2.032 at 35 degrees of freedom and α = 0.05. 
Since the test statistic of 6.135 is higher than the critical value, the difference is 
significant (t-test for paired samples: (|-6.135| > 2.032; p < 0.001, n = 36). 
 
Interindividual comparison of the test frequency in the Amsler group with that in the 
MacuFix group after the study day 
The Welch test was chosen because of the different sample sizes. In the comparison 
period the average time interval between two tests in the Amsler group was 19 days, 
whereas in the MacuFix® group the next test was performed after an average of six 
days. The average time to the next test was 13 days shorter in the MacuFix® group 
(95% CI: [3.82; 23.37]), t (7.98) =3.21). This difference was statistically significant (p 
< 0.05). 
 
Comparison of the frequency of the Amsler test before the study day 
In order to determine whether the group of patients who used the Amsler test 
throughout the study (group “Stay”) differed in their general self-behavior from those 
who switched to the App MacuFix®,(group “Switch”) the test frequency data was 
compared before the study day.  
In the baseline period the average time interval between two Amsler tests in the 
"Stay" group was 26 days. In the "Switch" group, the next test was performed after an 
average of 31 days during the baseline period. The time to the next test showed no 
statistically significant difference when using the Welch test in both groups (95%-KI: 

[-21.60; 10.66]), t (15.91) = -0.72; p>0.05. In the baseline period subjects who used 
the Amsler test continuously and those who switched to the App MacuFix® later 
showed no difference in their test behavior. 
 
Test behavior dependent on gender 
Six of the seven subjects who did not use a home test before the study were men. 
Two of these men continued not use any home tests after the study day, four of them 
used the MacuFix® test. Thus, 60% of the men and one woman who had not applied 
any home test previously, decided to use the MacuFix® test after the study day. 
The group of subjects who used the Amsler test in the baseline period consisted of 
18 females and 20 males.  Eight female subjects from this group continued to 
perform the Amsler test after the study day. The remaining ten females switched to 
the MacuFix® test after the study, as did all 20 males in this group. Thus, in the 
group that had already used the Amsler test before the study, 55% of the women and 
100% of the men decided to use the MacuFix® test instead of the Amsler tests for 
self-monitoring in the future. 
 
Proportion of patients who did not use a home test 
Prior to the study seven of 45 patients (15.5%) did not use any home test to evaluate 
their macular function. After the study five of these patients used the App MacuFix®, 
whereas two of 45 patients (4.4%) continued not to use any home test. 
The odds ratio for persons previously not using a home test to imply a home test in 
their routine was 4.5 (OR=7/38: 2/43= 4.5) due to MacuFix®. 
 
 
 

Discussion 
The current study evaluated the comparative data of 45 patients using the application 
MacuFix® and the standard functional test, Amsler Grid. Regarding sensitivity and 
specificity, comparability of MacuFix® and the Amsler Grid, is to some extent limited, 
because MacuFix® tests the central 4° of the visual field whereas the Amsler Grid 
examines 10° when used in the intended distance. 
 
Transferability into everyday care 
According to the SUS questionnaire, the study participants found the test easy to 
learn and uncomplicated, which may also be due to the playful character of the app. 
When using the SUS questionnaire, the app received the worst score on the question 
no. 6  "I think there are too many inconsistencies in the test". In order to reduce 
barriers to implementing the intervention, the help function for using the app has 
been revised in the meantime with the cooperation of patients, educators and 
linguists and the display of the test results has been improved. 
An improvement in health care through self-monitoring tools may possibly improve 
diagnostic and subsequently therapeutic adherence and persistence, thus leading to 
better maintenance of the patient's vision. Home monitoring and telemedicine using 
computer-based testing is especially important in resource deprived areas, for less 
mobile patients such as those in senior care homes or when reduced contacts are 
desirable, as has been highlighted by the ongoing Covid-19 pandemic.[11-14]  
Amsler grid test is popular as it is inexpensive and can be easily explained to the 
patients for assessment of progressive macular damage. Unmet needs in home 
monitoring of macular function are derived from the limitations of the Amsler grid 
such as the non-interactive nature of the test, the missing fixation control during the 
test, the need for reasonable reading vision to discern the lines, a low sensitivity due 

to a suprathreshold stimulus, its poor performance due to the ‘crowding effect' and 
limited awareness of visual field defects until the scotoma is significantly large in size 
due to ‘filling-in phenomenon'.[15,16]  
Some of the ophthalmic home-based tests developed so far do not satisfy the needs 
of patients due to complicated handling and/or high purchase price and/or regulated 
access. These patients can either not afford, do not have access to devices for 
testing due to regulatory hurdles or do not want or are unable to use new 
technologies. The AREDS2-HOME study revealed that 20% of patients who were 
offered the hyperacuity-based ForeseeHome monitoring device (Notal Vision Ltd, Tel 
Aviv, Israel) were unable to use it successfully due to visual field defects or problems 
with its application. [17]  
Diagnostic and therapeutic adherence are crucial for treatment persistence. Ehlken et 
al observed that 44% of their patients did not reveal sufficient adherence in the first 
year of treatment.[18] The AURA study highlighted the role that regular monitoring 
plays in guiding neovascular AMD (nAMD) therapy.[19] The OCEAN study showed 
that a timely start of therapy leads to an improved outcome, but unfortunately only 
60% of patients continued the therapy after two years.[20] The POLARIS study found 
that the adherence of patients with DME is lower compared to AMD patients.[21] The 
ANDROMEDA study investigates the factors that influence the adherence in patients 
with AMD.[22]  
Delayed diagnosis or detection of progression of metamorphopsia account for poor 
visual prognosis and this opens up an area of application for home monitoring and 
telemedicine. Pinnacle clinical trials evaluating anti–vascular endothelial growth 
factor (VEGF) therapies in management protocols for nAMD have demonstrated 
significant visual acuity gains, yet these same benefits are not always reflected in 
real-world patient analyses. In a systematic review, Carrasco et al. described real-

world outcomes in the treatment of AMD by intravitreally administered antivascular 
growth factors (anti-VEGF) and found that the amount of the visual acuity gain as 
seen in the studies was superior to the visual acuity gain seen in the real world 
settings.[23]  
Angermann et al. retrospectively analyzed data of 1264 patients with diabetic 
retinopathy or nAMD receiving treatment with anti-VEGF between 2015 and 2018.[24] 
Multivariate regression analysis showed that advanced age, lack of mobility, and 
need for assisted transport, poor final visual acuity despite treatment, and decrease 
in vision during the observational period were independent risk factors for terminating 
the treatment. The authors concluded that taking the risk of disease progression into 
account, strategies for better compliance and adherence to therapy should be 
considered to optimize patient care. The aspect of improving adherence is crucial as 
well for partner eyes bearing an annual risk of conversion to nAMD of 24%.[25] The 
authors of the post-hoc analysis of the VIEW study requested close monitoring of 
these eyes at risk.[26]   
Macufix® has been shown to be a reliable tool for metamorphopsia detection in AMD 
patients.[27] In the present study, the usability of the Macufix® App was rated as 
excellent  and its availability increased the test frequency by a factor of 3. Therefore, 
we suggest that MacuFix® can safely be offered as a home monitoring solution that 
can connect patients or individuals at risk for macular disease with their eye care 
professional and thus improve patient self-management. 
 
Limitations of the study 
A selection bias may be due to the fact that study participants were recruited from our 
own patient pool who may have been particularly motivated to perform and rate the 
test positively in the sense of social desirability. An observation bias may have arisen 

from the announcement and conduct of a telephone interview and thus have 
influenced adherence. 
In the present study, a randomization was deliberately avoided, since it does not 
represent the everyday practice pattern: patients select a home monitoring test 
mainly based on their own decision and will accomplish it based on an intrinsic 
motivation. The allocation in the context of a randomization can falsify this picture 
and assign patients to a test, which they would not select of their own free will. 
In diseases which result in metamorphopsia, a variety of factors such as age, 
experience with electronic media, visual acuity, other diseases affecting visual acuity 
or the visual field such as cataract or glaucoma, can influence the test adherence to 
an app as confounders. The risk of statistical bias was reduced in our study by intra-
individual comparison. 
 
Conclusion 
Therapeutic agents and dosing strategies designed to overcome treatment burden by  
extending the time between dosing intervals continue to evolve and thus have the 
potential to improve quality of life and visual outcomes in patients with AMD, 
particularly nAMD, when integrated into clinical practice. To avoid discrepancies 
between clinical trials and real-world data due to undertreatment of patients with 
nAMD or DME, even with these upcoming treatment algorithms, strategies that 
strengthen patient adherence will become more important. The high user satisfaction 
and increased testing frequency observed with the use of MacuFix® may lead to 
improved outcomes in the treatment of macular disease. 
 
 
 

References: 
1. 
Amsler M. Die Untersuchung des qualitativen Sehens mit dem quadratischen 
Netz. Anweisung zum Gebrauch der Testtafeln. : Theodore Hamblin LTD; 1958. 
2. 
Arimura E, Matsumoto C, Okuyama S, Takada S, Hashimoto S, Shimomura Y. 
Quantification of metamorphopsia in a macular hole patient using M-CHARTS. Acta 
Ophthalmol Scand. 2007;85(1):55-9. 
3. 
Chew EY, Clemons TE, Bressler SB, Elman MJ, Danis RP, Domalpally A, et 
al. Randomized trial of a home monitoring system for early detection of choroidal 
neovascularization home monitoring of the Eye (HOME) study. Ophthalmology. 
2014;121(2):535-44. 
4. 
Coco-Martin RM, Pichel-Mouzo M, Fernandez I, Plata-Cordero M, Lopez-
Miguel A. Reliability of colour perimetry to assess macular pigment optical density in 
age-related macular degeneration. Eur J Ophthalmol. 2020;30(6):1480-6. 
5. 
Welker SG, Pfau M, Heinemann M, Schmitz-Valckenberg S, Holz FG, Finger 
RP. Retest Reliability of Mesopic and Dark-Adapted Microperimetry in Patients With 
Intermediate Age-Related Macular Degeneration and Age-Matched Controls. Invest 
Ophthalmol Vis Sci. 2018;59(4):152-9. 
6. 
Ward E, Wickens RA, O'Connell A, Culliford LA, Rogers CA, Gidman EA, et al. 
Monitoring for neovascular age-related macular degeneration (AMD) reactivation at 
home: the MONARCH study. Eye (Lond). 2020. 
7. 
Claessens D, Schuster AK. Correlation of Quantitative Metamorphopsia 
Measurement and Central Retinal Thickness in Diabetic Macular Edema and Age-
Related Exsudative Macular Degeneration. Klin Monbl Augenheilkd. 
2019;236(7):877-84. 

8. 
Claessens D, Schuster AK, Krüger RV, Liegl M, Singh L, Kirchhof B. Test-
Retest-Reliability of Computer-Based Metamorphopsia Measurement in Macular 
Diseases. Klin Monbl Augenheilkd. 2020 Dec. 7.(Epub ahead of print) 
9. 
Bangor A, Kortum PT, Miller JT. An Empirical Evaluation of the System 
Usability Scale. International Journal of Human-Computer Interaction. 
2008;24(6):574-94. 
10. 
Brooke J. SUS-A quick and dirty usability scale. In: Corporation DE, editor. 
Usability Evaluation In Industry. London: CRC Press; 1996. 
11. 
Muether PS HR, Hermann MM, Kirchhof B, Fauser S. Long-term effects of 
ranibizumab treatment delay in neovascular age-related macular degeneration. 
Graefes Arch Clin Exp Ophthalmol 2013(251):453–8. 
12. 
Lim JH, Wickremasinghe SS, Xie J, Chauhan DS, Baird PN, Robman LD, et 
al. Delay to treatment and visual outcomes in patients treated with anti-vascular 
endothelial growth factor for age-related macular degeneration. Am J Ophthalmol. 
2012;153(4):678-86. 
13. 
Framme C, Eter N, Hamacher T, Hasanbasic Z, Jochmann C, Johnson KT, et 
al. Aflibercept for Patients with Neovascular Age-Related Macular Degeneration in 
Routine Clinical Practice in Germany: Twelve-Month Outcomes of PERSEUS. 
Ophthalmol Retina. 2018;2(6):539-49. 
14. 
Wintergerst MWM, Bouws J, Loss J, Heimes B, Pauleikhoff D, Holz FG, et al. 
Reasons for delayed and discontinued therapy in age-related macular degeneration. 
Ophthalmologe. 2018;115(12):1035-41. 
15. 
Achard OA, Safran AB, Duret FC, Ragama E. Role of the completion 
phenomenon in the evaluation of Amsler grid results. Am J Ophthalmol. 
1995;120(3):322-9. 

16. 
Parkes L, Lund J, Angelucci A, Solomon JA, Morgan M. Compulsory 
averaging of crowded orientation signals in human vision. Nat Neurosci. 
2001;4(7):739-44. 
17. 
Domalpally A, Clemons TE, Bressler SB, Danis RP, Elman M, Kim JE, et al. 
Imaging Characteristics of Choroidal Neovascular Lesions in the AREDS2-HOME 
Study: Report Number 4. Ophthalmol Retina. 2019;3(4):326-35. 
18. 
Ehlken C, Helms M, Bohringer D, Agostini HT, Stahl A. Association of 
treatment adherence with real-life VA outcomes in AMD, DME, and BRVO patients. 
Clin Ophthalmol. 2018;12:13-20. 
19. 
Holz FG, Tadayoni R, Beatty S, Berger AR, Cereda MG, Hykin P, et al. 
Determinants of visual acuity outcomes in eyes with neovascular AMD treated with 
anti-VEGF agents: an instrumental variable analysis of the AURA study. Eye (Lond). 
2016;30(8):1063-71. 
20. 
Holz FG, Tadayoni R, Beatty S, Berger A, Cereda MG, Cortez R, et al. Multi-
country real-life experience of anti-vascular endothelial growth factor therapy for wet 
age-related macular degeneration. Br J Ophthalmol. 2015;99(2):220-6. 
21. 
Ulbig M, Höh H, Schmickler S, Wolf A, Dimopoulos S, Lorenz K, et al. 
Treatment reality with ranibizumab in clinical routine use for patients with diabetic 
macular edema : 1‑year results of the German POLARIS cohort. Ophthalmologe 
2019;116(7):631-9. 
22. 
Holz FG, Johnson KT, Bauer-Steinhusen U, Rech C, Machewitz T, Muller S, et 
al. ANDROMEDA-an investigation of factors influencing the adherence of patients 
with neovascular age-related macular degeneration using the newly developed 
patient questionnaire LAF-IVT. Ophthalmologe. 2019;117(8):765-74. 
23. 
Carrasco J, Pietsch GA, Nicolas MP, Koerber C, Bennison C, Yoon J. Real-
World Effectiveness and Real-World Cost-Effectiveness of Intravitreal Aflibercept and 

Intravitreal Ranibizumab in Neovascular Age-Related Macular Degeneration: 
Systematic Review and Meta-Analysis of Real-World Studies. Adv Ther. 
2020;37(1):300-15. 
24. 
Angermann R, Rauchegger T, Nowosielski Y. Treatment compliance and 
adherence among patients with diabetic retinopathy and age-related macular 
degeneration treated by anti-vascular endothelial growth factor under universal 
health coverage. Graefes Arch Clin Exp Ophthalmol. 2019;257(10):2119-25. 
25. 
Parikh R, Avery RL, Saroj N, Thompson D, Freund KB. Incidence of New 
Choroidal Neovascularization in Fellow Eyes of Patients With Age-Related Macular 
Degeneration Treated With Intravitreal Aflibercept or Ranibizumab. JAMA 
Ophthalmol. 2019; 137(8):914-20. 
26. 
Heier JS, Brown DM, Chong V, Korobelnik JF, Kaiser PK, Nguyen QD, et al. 
Intravitreal aflibercept (VEGF trap-eye) in wet age-related macular degeneration. 
Ophthalmology. 2012;119(12):2537-48. 
27. 
Krüger R, Claessens D. Reliability of a Novel Computer-Based 
Metamorphopsia Categorization Tool.  Association for  Research and Vision  in 
Ophthalmology; Baltimore 2020. 
 
Figure legends: 
Figure 1: MacuFix used on a Smartphone 
Table Legend: 
Table 1: Average values of individual questions in the SUS questionnaire 
 
 
 
 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Table 1: Average values of individual questions in the SUS questionnaire 
 
Question number and text of the question 
Average value 
1. I can well imagine using the test regularly.  
2,8 
2. I find the test unnecessarily complicated. 
 
3,1 
3. I find the test easy to use. 
 
3,0 
4. I think I would need technical support to use the test. 
3,1 
5. I find that the various functions of the test are easy to use. 
2,8 
6. I think that there are too many inconsistencies in the test. 
2,6 
7. I can imagine that most people learn to master the test quickly. 
3,3 
8. I find the operation very complicated. 
3,4 
9. I felt very confident in using the test. 
3,2 
10. I had to learn a lot of things before I could work with the test. 
3,4