Title: Induced Peripheral Blur and its Effect on Visual functions
Authors: Eman A. Alzghoul1, Pauline Kang1, Sieu Khuu1
- University of New South Wales, Sydney, New South Wales, Australia
Reference: ARVO 2021 Abstract
In this study, young adults were fit with CooperVision Proclear multifocal contact lenses with the near add chosen to generate either a +0.50 or +1.00 of peripheral blur. Whilst the specific add chosen is not clear, this was confirmed by measurement of peripheral refraction. Detection ability was tested with the Humphrey VFA using Goldmann Size I (0.56mm diameter, 0.25mm2) across the horizontal visual field up to 350 on either side. Compared to a single vision contact lens, detection ability was not affected by either multifocal contact lens.
What this means for your clinical practice: this is a positive indication that fitting multifocal contact lenses in young wearers doesn't impact peripheral visual performance. Whilst this research was done in young adults and not children, young wearers could be reasonably reassured wearing multifocal contact lenses shouldn't influence peripheral vision detection.
Purpose: Peripheral hyperopic defocus has been considered to be a contributing factor to myopic progression. Thus, it has been suggested that reducing peripheral blur may slow down myopia progression. However, how the eye recognizes optical blur in different meridians and responds to change in peripheral visual functions is not fully understood. This prospective study hypothesized that inducing myopic peripheral blur using utilized multifocal contact lenses will improve detection visual function and may be involved in reducing myopia progression. In this study, we quantified the impact of peripheral blur on visual function which may provide further insights on myopia development
Methods: 20 myopic subjects (Mean age 21 ± 2 years) were fitted with Proclear multifocal lenses of distance center design in one eye. All subjects were with a central spherical equivalent myopic refraction of -1.00D or more, ≤0.75DC cylindrical power, and 1.00D or more peripheral blur at the horizontal visual field. Peripheral refraction and detection acuity were measured with the contact lens on the eye. All measurements were taken along the horizontal meridian at ±10o, ±20o, ±30o, and ±35o, and under three conditions; no blur, +0.50D, and +1.00D. Linear mixed model and Post-hoc t-tests were used for statistical analysis; to assess changes in visual functions under different peripheral defocus conditions
Results: Compared to the baseline, peripheral refraction was significantly more hyperopic at all points along the horizontal meridian when compared to the center except at nasal and temporal 10o (p < 0.05). No significant difference was found in detection ability with varying amounts of peripheral blur at different locations (p=0.764). However, detection acuity was highest centrally (+/- 10 degrees) and gradually started to decrease peripherally with the lowest acuity at location +/- 35 degrees
Conclusions: The results of this study showed that inducing optical blur changed peripheral refraction across horizontal meridian when compared to spherical contact lenses. Further, the results showed that inducing optical defocus does not change peripheral detection ability along the horizontal visual field which contradicts our hypothesis that improvement in peripheral visual function may be involved in reducing myopia progression. However, more studies need to be conducted to comprehensively establish the impact of hyperopic blur on peripheral detection abilities
Disclosures: Eman A. Alzghoul, None