The efficacy of biofeedback visual rehabilitation therapy in patients with infantile nystagmus syndrome: A retrospective study.

OBJECTIVE: To report fixation stability changes in patients with different forms of infantile nystagmus syndrome (INS), who have undergone a visual rehabilitation through biofeedback fixation training (BFT) with microperimetry (MP). DESIGN: Retrospective study. METHODS: Patients 6 to 12 years-old with INS who performed BFT with MP. Initially 10 once-weekly followed by eight twice-weekly sessions of BFT during a minimum of 6 months period were performed. Visual acuity (VA) and MP fixation stability indices were analyzed, including displacement from fixation point (P1, P2) and percentage of retinal loci used during fixation attempt (BCEA 63% and 95%). Statistical analysis was conducted at baseline (BL), 10 weeks (W10) and 6 months (M6). RESULTS: Twelve patients (mean age 8.9 years.) with INS completed the whole training session. All patients showed significant improvement in the mean BCEA fixation area (deg2): For BCEA@95% BL was 78.0, 46.1 at W10, and 27.4 at M6 (p-value = 0.004). For BCEA@63% BL was 27.3, 15.4 in W10, and 9.17 at M6 (p = 0.01). The ANOVA test for the FS indices of P1 and P2, as well as for BCVA showed no significant difference when compared at the same intervals. CONCLUSION: Fixation stability (FS) indices of BCEAs (63% and 95%) improved at W10 and M6, while P1 and P2 showed significant improvement at W10 but not at M6, probably because BCEA involves a much larger area than P1 and P2. VA did not show significant improvement at any time point.

Biofeedback fixation training method for improving eccentric vision in patients with loss of foveal function secondary to different maculopathies.

PURPOSE: Fixation stability (FS) of the preferred retinal locus (PRL) may be improved by biofeedback fixation training (BFT) with microperimetry. Such training can be done on the patient's PRL or in different retinal loci with better functional characteristics. We studied both options and compared the outcomes. METHODS: Sixty-seven consecutive patients with bilateral central vision loss, poor FS and visual acuity (VA) lower than 0.3 LogMAR were recruited for BFT with microperimeter. Patients were assigned into 2 groups. In group A, BFT was performed on the patient's spontaneous PRL. In group B, PRL was located between 2 adjacent loci with the highest light sensitivity and the lowest distance from the fovea. Two sets of 12 weekly BFT sessions were performed. Primary outcomes were: FS, VA and reading speed. RESULTS: Outcomes were statistically significantly better in group B. Mean percentage of FS at therapy end improved from 32 to 35% for group A and from 40 to 55% in group B. Mean VA improved from 1 to 0.86 in group A and from 1 to 0.84 in group B. Reading speed (wpm) improved from 56 to 58 in group A and from 63 to 89 in group B. CONCLUSIONS: This study describes a reliable methodology of improving eccentric fixation stability using BFT in microperimetry, when the fixation training locus is individualized as the retinal area with best functional characteristics. Further studies are needed to validate its value in a larger scale of patients, at different stages of the disease, and its persistence over time.

Spontaneous onset pseudophakic malignant glaucoma secondary to zonular weakness and cilio-lenticular block.

Malignant glaucoma (MG), also known as aqueous misdirection and cilio-vitreo-lenticular block, is an infrequent cause of secondary angle closure glaucoma. Despite conventional treatment, it often has a poor visual outcome. It is recognized clinically by raised intraocular pressure associated with shallowing of the peripheral and central anterior chamber in the presence of a patent peripheral iridotomy/iridectomy. Despite being known to occur after a variety of surgical procedures, it most commonly presents following filtration surgery in hypermetropic eyes with angle closure glaucoma. It can present within a range of postsurgical latencies, ranging from 1 day to many months. We describe a case of pseudophakic MG that was unusual in that it presented spontaneously many years following cataract surgery. We postulate the etiology of our spontaneous onset pseudophakic MG was the anterior subluxation of the large diameter intraocular lens secondary to zonular weakness.

Test-Retest Reliability of Scotopic and Mesopic Fundus-Controlled Perimetry Using a Modified MAIA (Macular Integrity Assessment) in Normal Eyes.

PURPOSE: To assess the intrasession test-retest reliability of scotopic cyan and scotopic red fundus-controlled perimetry (FCP) in normal subjects using a modified MAIA "microperimeter" (macular integrity assessment) device. METHODS: Forty-seven normal eyes of 30 subjects (aged 33.8 years) underwent duplicate mesopic (achromatic stimuli, 400-800 nm), scotopic cyan (505 nm), and scotopic red (627 nm) FCP, using a grid of 49 stimuli over 14° of the central retina. Test-retest reliability for pointwise sensitivity (PWS), stability of fixation, reaction time and test duration were analyzed using mixed-effects models. RESULTS: PWS test-retest reliability was good among all 3 types of retinal sensitivity assessments (coefficient of repeatability of 4.75 dB for mesopic, 5.26 dB for scotopic cyan, and 4.06 dB for scotopic red testing). While the mean sensitivity decreased with eccentricity for both mesopic and scotopic red testing, it was highest at 7° eccentricity for the scotopic cyan assessment (p < 0.001). CONCLUSIONS: The modified MAIA device allows for reliable scotopic FCP in normal subjects. Our findings suggest that testing of scotopic cyan sensitivity largely reflects rod function.

Reference Clinical Database for Fixation Stability Metrics in Normal Subjects Measured with the MAIA Microperimeter.

PURPOSE: The purpose of this study was to establish a normal reference database for fixation stability measured with the bivariate contour ellipse area (BCEA) in the Macular Integrity Assessment (MAIA) microperimeter. METHODS: Subjects were 358 healthy volunteers who had the MAIA examination. Fixation stability was assessed using two BCEA fixation indices (63% and 95% proportional values) and the percentage of fixation points within 1° and 2° from the fovea (P1 and P2). Statistical analysis was performed with linear regression and Pearson's product moment correlation coefficient. RESULTS: Average areas of 0.80 deg2 (min = 0.03, max = 3.90, SD = 0.68) for the index BCEA@63% and 2.40 deg2 (min = 0.20, max = 11.70, SD = 2.04) for the index BCEA@95% were found. The average values of P1 and P2 were 95% (min = 76, max = 100, SD = 5.31) and 99% (min = 91, max = 100, SD = 1.42), respectively. The Pearson's product moment test showed an almost perfect correlation index, r = 0.999, between BCEA@63% and BCEA@95%. Index P1 showed a very strong correlation with BCEA@63%, r = -0.924, as well as with BCEA@95%, r = -0.925. Index P2 demonstrated a slightly lower correlation with both BCEA@63% and BCEA@95%, r = -0.874 and -0.875, respectively. CONCLUSIONS: The single parameter of the BCEA@95% may be taken as accurately reporting fixation stability and serves as a reference database of normal subjects with a cutoff area of 2.40 ± 2.04 deg2 in MAIA microperimeter. TRANSLATIONAL RELEVANCE: Fixation stability can be measured with different indices. This study originates reference fixation values for the MAIA using a single fixation index.

Screening Patients With Cataract for Premium IOL Candidacy Using Microperimetry.

PURPOSE: To explore the use of microperimetry in the evaluation of macular dysfunction in patients with cataract, to aid in proper intraocular lens selection (multifocal vs monofocal), and to set expectations for postoperative visual function. METHODS: One randomly chosen eye of 10 patients diagnosed as having mild (1+) to moderate (3+) cataract was evaluated before and 1 week after cataract surgery with the MAIA microperimeter (Centervue S.p.A, Padova, Italy). Corrected distance visual acuity, dilated and undilated biomicroscopy and indirect fundus examinations, intraocular pressure measurement, and a MAIA microperimeter test to measure macular sensitivity and fixation pattern were also performed. RESULTS: Two patients showed macular abnormalities before and after surgery that were noted on MAIA testing: one patient showed reduced average threshold sensitivity and abnormal percent reduced threshold, whereas the other patient showed fixation drift demonstrating eccentric fixation. Both eyes had reduced postoperative visual performance after uneventful cataract surgeries. CONCLUSIONS: Because not every macular lesion noted on fundus examination or optical coherence tomography may be clinically significant, microperimetry can be useful to detect clinically significant retinal dysfunction prior to cataract surgery. The outcome may aid in the selection of intraocular lens type and may yield a better documented surgical prognosis. Further studies are necessary to confirm these findings.