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P. Limoli, E.M. Vingolo, L.M. D'Amato, R. Solari, E. Giacomotti, R. Di Corato, P. Costanzo; Microperimetry and Fixation in the Low Vision Patient . Invest. Ophthalmol. Vis. Sci. 2005;46(13):4330.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: We have studied the relation between quality of fixation and visual acuity (BCVA, near BCVA, retinal sensitivity in microperimetry MP1) in order to understand better the role of neural photostimulation during the rehabilitation of the low vision patients. Patients and methods. First of all, we analized fixation in microperimetry on a large and eterogeneus group of people (265 eyes ) in order to comphrehend the correlation between all visual parameters. Then we analized the effects of neural photostimulation not only on traditional visual parameters but also on fixation examined with microperimetry. Then we analized a second group of 22 eyes, that underwent 10 sessions of neural photostimulation in order to study at the beginning (T0) and at the end (T1) of the therapy, the following parameters: BCVA near, near BCVA in pts, retinal sensitivity in decibels tested with MP1. In the rehabilitative project we have used visual pathfinder (VPF) that is a photostimulative method which can improve visual performance in low vision and ambliopic patients or in anyone who needs to improve his visual acuity. Results: In the patients of the first group of 256 eyes in which we studed the relation between quality of fixation and visual acuity, we obtained with T–Test, an highly significative correlation between percentage of fixation within 2° and BCVA (R=0,497 P<0,0001) and between percentage of fixation within 2° and near visual acuity (R=0,414 P<0,0001). In the patients of the second group of 22 eyes we obtained the following results: 1) average fixation within 2° changes from 52% (T0) to 66% (T1) (R=0,019677866 Standard deviation 33,76488605). 2) near visual acuity changes from 22,2 pts (T0) to 16,1 (T1) (R=0,002380547 SD 16,71085108). 3) average BCVA changes from 0,38 (T0) to 0,45 (T1) (R=0,039093802 SD 0,344299151). 4) average sensititvity in decibels changes from 6,5 dbs (T0) to 7,7 dbs (T1) (R=0,0512 SD 4,6461). Conclusions: The effects of a better fixation within 2° causes an improvement of foveal detection which determines an improvement of visual acuity. Besides, a better fixation explains the improvements of reading performances (ARVO 2004), which reduces regression and improves the amplitude of saccadic movements along the reading line. We think that neural photostimulation can increase the fixation percentage and foveal detection, such as has been analized with microperimetry, and can be successfully combined with visual rehabilitation.
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