Purpose/Aim: We aimed to investigate the effect of monocular blur on the binocular visual field. Materials and Methods: A total of 13 healthy young volunteers participated in this study. The mean subjective refractive error of the dominant eye (DE) was -3.33 ± 1.65D, and the non-dominant eye (NDE) was -3.15 ± 2.84D. The DE was determined by using the hole-in-the-card test. The visual field was examined by the Humphrey Visual Field Analyzer using the 30-2 SITA Standard program. The visual field was measured while wearing soft contact lens under three conditions; ① both eyes: near vision correction; ② DE: near vision correction +3.00D added, NDE: near vision correction; and ③ DE: near vision correction, NDE: near vision correction +3.00D added. The foveal threshold, mean deviation (MD), and pattern standard deviation (PSD) values were investigated. Results: The foveal threshold value (dB) at ①, ②, and ③ was 41.2, 37.8, and 38.1, respectively. The values at ② and ③ were both significantly lower than that at ① (p < 0.0001; p = 0.0003). The MD value (dB) at ①, ②, and ③ was 1.67, 0.19, and 0.51, respectively; the values at ② and ③ were both significantly lower than that at ① (p = 0.0012; p = 0.0118). The PSD value (dB) at ①, ②, and ③ was 1.36, 1.55, and 1.47, respectively. A significant difference in ①, ②, and ③ was not found. Conclusion: These results suggest that monocular blur reduced the sensitivity within the binocular visual field.
In general, visual field is measured under monocular view in clinics. However, in daily life, visual information is managed with both eyes open. To consider the vision quality for a patient’s daily life, evaluating the visual field under binocular open view is important. In cases of monocular visual field abnormality, visual field abnormality is complemented by the normal visual field of the fellow eye under binocular open view condition. Hence, awareness of the visual disturbance is difficult for the patient. In contrast, many patients with monocular cataract also complain under binocular open view condition. However, there are fewer studies on the effect of monocular blur on the binocular visual field result.
In this study, we created a monocular pseudo blur in this study, and investigated the effect of monocular blur within the binocular visual field.
We examined 13 healthy young volunteers (1 man and 12 women; mean age, 21 [range: 20 - 22 years]) in this study, and have publicly invited subjects by poster postingat School of Allied Health Sciences, Kitasato University. All subjects underwent ophthalmology examination. Subjects were excluded from the study if they had any ophthalmologic disease except refractive error. The mean subjective refractive error (spherical equivalent value, SE) of the dominant eye (DE) was −3.33 ± 1.65D, and the SE of the non-dominant eye (NDE) was −3.15 ± 2.84D. The dominant eye was determined by using the hole-in-the-card test. The visual field was examined by using the Humphrey Visual Field Analyzer 740 (Carl Zeiss, Dublin, CA) using Swedish Interactive Threshold Algorithm 30-2 SITA Standard. We measured the visual field while wearing soft contact lens under the following three conditions:
1) Both eyes: near vision correction (both near conditions)
2) DE: near vision correction +3.00D addition/NDE: near vision correction (DE blur condition)
3) DE: near vision correction/NDE: near vision correction +3.00D addition (NDE blur condition)
The measurement of these three conditions was randomly performed. We placed the center of both eyes that coincides with the center of the fixation monitor during the measurement. Subsequently, we compared the foveal threshold, mean deviation (MD), and pattern standard deviation (PSD) values between the measurements of the three conditions.
The study protocol was approved by the Institutional Review Board at the School of Allied Health Sciences of Kitasato University (number 2015-020) and followed the tenets of the Declaration of Helsinki. Informed consent was obtained from all patients after explanation of the nature and possible consequences of the study.
Statistical analysis was performed by using IBM SPSS statistics software (version 23.0; IBM Corporation, Armonk, NY, USA). The Tukeytest was used to compare the foveal threshold, MD, and PSD values between the measurements of the three conditions. The level of statistical significance was set at a p-value less than 0.05.
In this study, significant differences were found between both near conditions and DE blur, NDE blur conditions in the foveal threshold values and MD values.
Pardhan et al. [
Based on these results, no significant difference was found in the foveal threshold, the MD, and PSD values under DE blur and NDE blur conditions, and the values under DE blur condition had a greater tendency to indicate deterioration.
Under natural viewing conditions, humans demonstrate ocular dominance, and this feature is an important aspect of binocular vision. Usually, the dominant eye plays a controlling role in binocular vision [
In this study, a convex lens of 3.00D was added to create the pseudo monocular blur. It was inferred that not to be the result of reflecting the chief complaint against the natural viewing of patients because this situation is different from the blur encountered in conditions such as cataracts. This may have resulted in aniseikonia by adding the convex lens to the eye, and this situation possibly affects the fusion in binocular vision. Moreover, the perimeter used in this study has not been designed for measuring the visual field under binocular open view. Fixation monitoring, eye position, and fusion situation during the measurement were not observed; hence, these can be cited as problems. We considered examining and improving the testing method for these points necessary in the future.
In this study, we investigated the effect of monocular blur to the binocular visual field by monocular pseudo blur. The sensitivity decrease within the binocular visual field was suggested to be influenced by the monocular blur.
Data can be shared upon request.
Conception and design of the study (FF, NS); analysis and interpretation (FF); writing the article (FF); critical revision of the article (FF, NS); data collection (FF); administrative, technical or logistic support (NS). All authors read and approved the final manuscript.
A written informed consent to publish study participant’s data was sought along with the consent for participation into the study.
This study was approved by the Institutional Review Board at School of Allied Health Sciences, Kitasato University (number 2015-020) and followed the tenets of the Declaration of Helsinki.
Fujimura, F. and Shoji, N. (2018) The Effect of Monocular Blur on the Binocular Visual Field. Open Journal of Ophthalmology, 8, 12-17. https://doi.org/10.4236/ojoph.2018.81002