The authors would like to thank Dr. J. C. Barry for his comments on our article (1). The authors’ aim was to prevent the patients’ odyssey from specialist to specialist described in the opening part of his letter. The diagnostic tests mentioned are performed easily and quickly. With the help of these tests, a physician who is not practicing in ophthalmology can adequately differentiate between the described visual disturbances and refer a patient to an ophthalmological-optical specialist, if necessary—avoiding the long journeys described in the letter.
There seems to be general agreement about the fundamental value of the pinhole test. In the opinion of the authors, the vitreous opacities mentioned by Dr. Barry are not included in the refractive errors addressed in this publication. (Circumscribed) vitreous opacities typically result in fluctuating local visual impairments. Those affected note the characteristic symptom of vitreous floaters, in particular along with eye movements while looking at a homogenous bright background: Typically, the shadows of such vitreous opacities continue moving even after the eye movement has stopped. This is explained by the inertia of the vitreous body (and circumscribed opacities contained therein) in relation to the wall of the eyeball.
In young individuals (and especially in children), viewing through a pinhole could in principle trigger accommodation. However, the authors think that this is unlikely, for the following reasons: In contrast to the so-called “instrument myopia“, which occurs, for example, when looking through an optical instrument, the overall depth of a pinhole is negligibly small. In addition, when a sieve-like pinhole occluder is held in front of a patient’s eyes, the impression of looking into an instrument does simply not occur (due to the numerous holes available to look through).
The authors would like to thank Prof. Schmidt for his additions. Due to the limitations imposed by the publisher with regard to text length and number of references, a CME article can never be exhaustive.
The condition of night myopia mentioned by Prof. Schmidt can indeed be a reason for nocturnal visual disturbances. Night myopia can be caused by numerous factors, including but not restricted to the presence of aberrations along with a large pupil diameter, e.g. in the form of spherical aberrations (due to an increased refractive power of peripheral parts of the lens) (2, 3).
With regard to the examination of metamorphopsia, the authors are grateful for the comments pointing out further methods available for the assessment of this visual disturbance. In this context, the method of the working group led by C. Matsumoto is worth mentioning as it allows to quantify this visual disturbance (4).
The authors did not intend to present the historical development of computerized visual acuity testing. They rather wanted to present the design of the Freiburg Visual Acuity Test (FrACT), a widely adopted and well-documented acuity testing tool which is available online.
Prof. Dr. med. Ulrich Schiefer
Hochschule Aalen, Germany
Conflict of interest statement
Prof. Schiefer has received honoraria for consultancy from Servier, Pharm-Allergan, and Haag-Streit and payments for lectures from Alcon Pharma, Pharm-Allergan, MSD-Chibret, Pfizer, and Oculus.
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|2.||López-Gil N, Peixoto-de-Matos SC, Thibos LN, González-Méijome JM: Shedding light on night myopia. J Vis 2012; 12 (5): 4 CrossRef MEDLINE|
|3.||Hope GM, Rubin ML: Night myopia. Surv Ophthalmol 1984; 29: 129–36 CrossRef|
|4.||Nomoto H, Matsumoto C, Arimura E, et al.: Quantification of changes in metamorphopsia and retinal contraction in eyes with spontaneous separation of idiopathic epiretinal membrane. Eye (Lond) 2013; 27: 924–30 CrossRef MEDLINE PubMed Central|