We thank Prof Gonzales de la Rosa for the comments regarding our paper. Agreement on issues among different laboratories can sometimes be problematic. When reputable laboratories disagree, it is usually not because one is right and the other is wrong. Rather, it is because there are differences in the manner in which each group views the problem, how they interpret the items under investigation, their prior experience, and the results of other investigators. We believe that our system of evaluating the merit and validity of scientific and clinical research is fair and provides the best current method of determining whether a research project is worthy of publication or not. Additionally, we believe in other factors in conducting research: 1) results by the inventor are usually better than those obtained by others who have no conflict of interest; 2) collaboration with others is advantageous; 3) critical peer review is a fair and just means of evaluating research; and 4) disagreements among different laboratories can be positive. Experiments and results are more powerful and compelling than arguments.
Prof Gonzales de la Rosa raised the suspicion that many patients with glaucomatous optic neuropathy (GON) were false positives, considering the greater optic disc size compared to normals (2.13 vs 1.81 mm 2 ). The average optic disc size based on the Heidelberg Retina Tomograph (HRT) database is 1.6 to 2.6 mm 2 ; thus differences within this range are probably unlikely to bias the inclusion criteria. Moreover, GON was based on masked consensus grading by expert graders (all experienced senior glaucoma specialists), with adjudication by a third, and all GON eyes showed at least 1 typical glaucomatous sign.
The relationship between optic disc size and glaucoma is complex. It is quite common to find greater disc areas in glaucoma and GON groups compared to controls in glaucoma studies. Larger optic discs increase the likelihood of diagnosis. Studies have reported that large optic discs may be more susceptible to glaucomatous damage based on biomechanical properties.
Our comment regarding the fair diagnostic ability of Pulsar in GON eyes was based on area under the receiver operating characteristic curve (ROC) values in different groups and not with other instruments. We are not in agreement with Prof Gonzales de la Rosa’s view that “it is widely accepted that the early diagnosis of glaucoma should be established using criteria of high specificity.” This may be true for population screening, but not in patients with suspect glaucoma where high sensitivity may be preferred over excellent specificity.
In summary, we stand by our published results and are confident that our collaborative efforts, acceptance through the peer review process, and comments from other laboratories are supportive of this work. However, we also encourage other laboratories and investigators who have no direct or indirect financial or other conflicting interest in this device to pursue further research in this area. In this view, we believe that this can serve as a challenge and an opportunity for other investigators to pursue issues related to Pulsar perimetry.