Correlation Between Optical Coherence Tomography and Photopic Negative Response of Flash Electroretinography in Ganglion Cell Complex Assessment in Glaucoma Patients.

Purpose: To investigate the correlation between the photopic negative response (PhNR) of the light-adapted flash electroretinography (ERG) and measurements of standard automated perimetry (SAP) and optical coherence tomography (OCT) in assessment of retinal ganglion cells' (RGCs) affection in glaucoma. Patients and Methods: A cross-sectional study included 40 eyes of glaucoma patients and 40 eyes of age- and gender-matched normal subjects. Participants underwent a complete ophthalmologic assessment, SAP, OCT, and light-adapted flash ERG using the extended PhNR protocol of the International Society for Clinical Electrophysiology of Vision (ISCEV). Glaucomatous eyes were divided into 3 subgroups: mild (n = 15), moderate (n = 11) and severe glaucoma (n = 14) according to the mean deviation (MD) of SAP. Measurements of SAP, OCT and ERG parameters were analyzed, and correlations between PhNR measurements and other study measurements were evaluated. Results: PhNR amplitudes and PhNR/b-wave ratios were significantly reduced in glaucoma cases compared to healthy controls, and they showed a significant and progressive decline across the three glaucoma subgroups (P < 0.05). An exception to this is PT (b-wave peak to PhNR trough) PhNR amplitude where its reduction was statistically non-significant when comparing between controls and mild glaucoma cases (P = 0.178), and between moderate and severe glaucoma cases (P = 0.714). PhNR amplitudes and PhNR/b-wave ratios correlated significantly with SAP and OCT parameters (P < 0.05). Conclusion: PhNR correlates well with SAP and OCT parameters in glaucoma assessment. PhNR could be a valuable supplementary tool for objective assessment of the RGCs' function in glaucoma.

Multifocal visual evoked potential for evaluation of open-angle glaucoma.

Background: To correlate multifocal visual evoked potential (mfVEP) findings with static automated perimetry (SAP) and spectral-domain optical coherence tomography (SD-OCT) in eyes with primary open- angle glaucoma (POAG). Methods: This cross-sectional study included a consecutive sample of 40 eyes of 40 patients with POAG. The participants underwent a complete ophthalmologic assessment, axial length (AL) measurement, and assessments with SAP, SD-OCT, and mfVEP. Results: POAG cases were aged 49.70 (14.16) years (mean [SD]) and most were females (n = 24, 60%). For eyes of patients with POAG, the mfVEP upper-ring signal-to-noise ratio (SNR) showed a significant negative correlation with best-corrected logMAR visual acuity (r = - 0.33; P = 0.038), and a significant positive correlation with the superior hemifield of the visual field (VF) and the inferior-quadrant retinal nerve fiber layer (RNFL) thickness (r = + 0.34; P = 0.030; r = + 0.51; P < 0.001, respectively). Similarly, the mfVEP lower-ring SNR showed a significant negative correlation with best-corrected logMAR visual acuity (r = - 0.36; P = 0.024) and a significant positive correlation with the inferior hemifield of the VF and superior quadrant RNFL thickness (r = + 0.55; P < 0.001 and r = + 0.70; P < 0.001, respectively). Conclusions: mfVEP is a promising tool for objective assessment of the VF in patients with POAG, as it is positively correlated with the VF and OCT RNFL thickness. Future longitudinal studies with a larger sample size and a specific glaucoma subtype, along with multiple follow-up evaluations, are warranted to confirm our preliminary results.

The role of mitomycin C and porcine extracellular matrix in phacotrabeculectomy.

PURPOSE: To compare between mitomycin C alone, porcine extracellular matrix alone, and combined low dose mitomycin C with porcine extracellular matrix in term of efficacy and safety in phaco-trabeculectomy surgery. STUDY DESIGN: Prospective comparative. METHODS: Sixty eyes of 60 patients complaining of primary open angle glaucoma and cataract, undergoing phaco-trabeculectomy, were distributed into three groups: group I: surgery was augmented with mitomycin C, group II with porcine extracellular matrix, and group III with porcine extracellular matrix combined with low dose mitomycin C. Intraocular pressure was evaluated, postoperatively, at day 1, week 1, and 1, 3, 6, 9, and 12 months. Bleb vascularity, pre- and post-operative intraocular pressure lowering medications, success of IOP control and complications were also evaluated. RESULTS: After 12 months, the mean preoperative intraocular pressure (mm Hg) improved from 30.85 ± 4.7, 33.8 ± 4.2, and 31.05 ± 5.4 mm Hg, in groups I, II, and III respectively, to 13.8 ± 4.7 (55.2%), 15.2 ± 4.8 (55%), and 13 ± 4.9 (58.1%) (p > 0.05). Success of IOP control, postoperative IOP lowering medications and complications were comparable (p > 0.05). Bleb vascularity was significantly different (p < 0.05). CONCLUSION: Mitomycin C, porcine extracellular matrix and their combination are equally effective in phacotrabeculectomy.

Quality of Vision after Deep Anterior Lamellar Keratoplasty (Fluid Dissection) Compared to Penetrating Keratoplasty for the Treatment of Keratoconus.

PURPOSE: To compare the visual quality of patients with keratoconus who underwent penetrating keratoplasty (PKP) or deep anterior lamellar keratoplasty (DALK) with fluid dissection. DESIGN: Cross-sectional, observational study. METHODS: Twelve eyes that underwent PKP (PKP group) were compared to 24 eyes that underwent DALK (DALK group) after complete removal of sutures and stability of refraction. Visual, refractive, corneal topographic, corneal aberrometry, and ocular aberrometry parameters were compared for both groups. The χ2 and Mann-Whitney U tests were used for comparisons as appropriate. P < 0.05 was considered statistically significant. RESULTS: Uncorrected and best spectacle-corrected visual acuity (UCVA and BSCVA, resp.), mean refractive spherical equivalent and mean refractive cylinder (MRSE and MRC, resp.), root mean square of the 3 mm and 5 mm OPD Scan (NIDEK Co. Ltd., Gamagori, Japan), steep and flat meridians (SimK1 and SimK2, resp.), and the difference (corneal cylinder) were not statistically significantly different between groups (P > 0.05, all comparisons). All aberrations, point spread functions (PSF), and the modulation transfer function (MTF) were not statistically different between groups (P > 0.05). CONCLUSION: For our small study, the postoperative PKP and DALK with fluid dissection patient groups had vision/optical quality parameters that were not statistically different. This may indicate that DALK with fluid dissection can replace PKP for keratoconus without compromising vision quality.

Pattern Visual Evoked Potential, Pattern Electroretinogram, and Retinal Nerve Fiber Layer Thickness in Patients with Migraine during and after Aura.

PURPOSE: To study pattern visual evoked potential (PVEP), pattern electroretinogram (PERG), and retinal nerve fiber layer (RNFL) thickness in patients with migraine during and after aura. MATERIALS AND METHODS: We included 60 eyes of 60 patients with migraine (Group 1) and 30 healthy volunteers (30 eyes) as controls (Group 2). Group 1 was studied twice, during a visual aura (1-a) and in between attacks (1-b). All participants underwent full ophthalmological examination, PVEP, PERG, and optical coherence tomographyOCT imaging of the RNFL thickness for each patient. RESULTS: RNFL thickness was found to be thinner in patients during the aura compared to controls. It increased significantly post-aura but remained lower than the controls. Prolonged P100 latency and decreased amplitude were found in patients during aura compared to controls with significant change in between attacks to values comparable to the controls. We found prolonged N95 latency and decreased amplitude in patients during aura compared to controls with significant change post-aura to values comparable to the controls. There was positive correlation between average RNFL thicknesses and VA and spherical equivalent; but it showed negative correlation with duration of migraine, attack duration, and aura duration. Multiple regression analysis showed that the most important determinants of average RNFL thickness in patients of migraine were attack and aura duration (beta = -0.21 and -0.26 and p = 0.03 and 0.04, respectively). CONCLUSION: Migraine attacks impose both functional and structural retinal changes. The functional changes are fully reversible after the aura but not the structural ones. So, vigorous prevention of migraine attacks would be protective for retina.