SQUARE GRID DEFORMATION ANALYSIS OF THE MACULA AND POSTOPERATIVE METAMORPHOPSIA AFTER MACULAR HOLE SURGERY.

PURPOSE: To investigate the correlation between postoperative metamorphopsia and macular deformation after macular hole surgery. METHODS: This study included 28 eyes of 28 patients who underwent vitrectomy and internal limiting membrane removal for an idiopathic macular hole. The retinal vasculatures were compared between preoperative and postoperative photographs, and postoperative deformation of the macula was assessed as deformation of the square grid. The displacement of each node was measured, and deformation of the grid was calculated as differences in the coordinates of the adjacent nodes. These parameters were analyzed to find correlation with metamorphopsia measured using the M-charts after 6 postoperative months. RESULTS: The average deformations in the vertical and horizontal lines of the grid were 94.29 µm and 49.72 µm, respectively. Perifoveal deformation was significantly greater than parafoveal deformation (P = 0.001∼0.019). The multiple regression analysis demonstrated that the vertical M-score correlated with superior perifoveal deformation of the vertical line on the fovea (P = 0.036), and the horizontal M-score correlated with temporal perifoveal deformation of the horizontal line on the fovea (P = 0.032). CONCLUSION: The parafoveal tissue was displaced with the fovea concurrently after internal limiting membrane removal in macular hole surgery causing perifoveal deformation, which correlated with postoperative metamorphopsia.

Comparison of conjunctival vascularity changes using optical coherence tomography angiography after trabeculectomy and phacotrabeculectomy.

PURPOSE: To compare bleb vascularity changes using optical coherence tomography angiography (OCT-A) between mitomycin-C (MMC)-augmented trabeculectomy and phacotrabeculectomy and to determine whether bleb vascularity measurements during preoperative and early postoperative periods could act as surrogate parameters to predict surgical outcomes. METHODS: We retrospectively reviewed data for 72 eyes from 72 glaucoma patients who underwent MMC-augmented trabeculectomy with/without cataract surgery. Bleb area scans were obtained using OCT-A during the preoperative period; 1, 2, 4, and 6 weeks postoperatively; and 2, 4, and 6 months postoperatively. For conjunctival vascularity analysis, a semi-automated program was used to calculate color and brightness densities of the selected area. RESULTS: Color and brightness densities were decreased in the trabeculectomy group during all periods but not in the phacotrabeculectomy group at 4 and 6 weeks, as well as 2, 4, and 6 months postoperatively. Color and brightness densities were significantly higher in the phacotrabeculectomy group than in the trabeculectomy group after 6 weeks and 2, 4, and 6 months postoperatively. A Kaplan-Meier survival graph indicated that intraocular pressure differed according to glaucoma type but not surgery type. Logistic regression analysis revealed that brightness density 1 week postoperatively was correlated with reoperation. CONCLUSIONS: Changes in conjunctival vascularity density measured by OCT-A differed according to the surgical method. Following trabeculectomy with MMC, brightness density 1 week postoperatively may be a predictive index for surgical outcomes.

Displacement of the Foveal Retinal Layers After Macular Hole Surgery Assessed Using En Face Optical Coherence Tomography Images.

BACKGROUND AND OBJECTIVE: To investigate the displacement of foveal retinal layers in surgically closed macular holes (MHs) after removal of the internal limiting membrane (ILM). PATIENTS AND METHODS: Medical records of 26 consecutive patients who underwent vitrectomy and removal of the ILM for idiopathic MH were retrospectively reviewed. En face optical coherence tomography images were exported at the level of the choroid, ellipsoid zone (EZ), and inner plexiform layer (IPL) at baseline and at 1, 3, and 6 months. The foveal center of the EZ and IPL was marked in the choroid en face image. The choroidal images were overlapped to match the vasculature in each patient, and the postoperative displacement of the foveal center was compared to baseline. RESULTS: The center of the EZ and IPL was displaced significantly toward the disc during the first 3 months. The mean horizontal displacement at 1, 3, and 6 months was 52.7 µm, 112.5 µm, and 115.4 µm, respectively, for the EZ and 75.2 µm, 117.1 µm, and 136.5 µm, respectively, for the IPL. The location of the foveal center was significantly correlated between the EZ and the IPL (P ≤ .016). CONCLUSIONS: The fovea was displaced nasally and slightly inferiorly after removal of the ILM. The displacement of the photoreceptor and inner retinal layers was concurrent. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:414-422.].

Evaluation of Functional Filtering Bleb Using Optical Coherence Tomography Angiography.

PURPOSE: This study investigated whether filtering blebs can be evaluated using optical coherence tomography angiography (OCT-A) and compared vascularity parameters with conventional bleb grading systems. METHODS: A total of 92 patients with glaucoma, who underwent mitomycin C-augmented trabeculectomy, were enrolled in this study, and 92 eyes were assessed in total. The participants underwent OCT-A in external mode and anterior segment photography for bleb evaluation. For evaluation of bleb vascularity, a blinded observer carefully drew the bleb area on the original OCT-A image using a semiautomated program that calculated the color and brightness densities of the selected area. A blinded observer also classified the grades of the bleb vessels using the Indiana Bleb Appearance Grading Scale (IBAGS) and Moorfields Bleb Grading System (MBGS). The vascularity parameters using OCT-A were compared with the IBAGS and MBGS results. In addition, the correlation between intraocular pressure (IOP) and the bleb vascularity parameters was assessed. RESULTS: Vessel density measured by OCT-A demonstrated excellent inter- and intraobserver reproducibility. The color and brightness densities were positively correlated with the IBAGS and MBGS vascularity scores. There was no difference in accuracy when predicting IOP risk using vascularity scores from the IBAGS and MBGS or when estimating IOP risk using the color and brightness densities on the net reclassification index. CONCLUSIONS: Bleb evaluation using OCT-A can evaluate vessel vascularity and showed correlation to the IBAGS and MBGS vascularity grading. TRANSLATIONAL RELEVANCE: Bleb vascularity measurements using OCT-A could potentially provide objective and quantitative vessel parameters for bleb evaluation following trabeculectomy.

Comparison between refractive outcomes between macula-on and macula-off retinal detachments after phaco-vitrectomy.

PURPOSE: To evaluate axial length (AL) measurements and refractive outcomes in vitrectomy combined with cataract operation for rhegmatogenous retinal detachment (RRD) with wholly detached macula. STUDY DESIGN: Retrospective, consecutive, comparative, clinical study. METHODS: We reviewed the data of patients treated by vitrectomy combined with cataract operation for RRD. The group "Attach" (n=31) consisted of eyes in which retina was not detached within 1.5 disc diameters from the foveal center, and the group "Detach" (n=33) consisted of eyes in which that area was detached entirely. Only those eyes inthe group "Detach", only the eyes (n=20) which AL were measured similar to those fellow eyes were compared to the group "Attach" (n=31). Refractive shift (RS) was defined as the average of the difference between postoperative spherical equivalent (SE) and predicted SE. RESULTS: AL was well measured by A-scan ultrasonography (A-scan) in all 31 eyes of the group "Attach" and their RS was ‒0.57 diopters (D). AL was measured by A-scan similar to the fellow eye in 20 of 33 eyes (60.6%) of the group "Detach", and the RS was ‒0.09 D. The AL difference as much as central subfield macular thickness (about 300um) can make this difference of RS (0.48 D, P=0.025) CONCLUSION: When AL can be measured by A-scan similar to its fellow eye in RRD with wholly detached macula, RS would be smaller than that of the wholly attached macula after phacovitrectomy. It assumed that AL was measured from the RPE under the detached macula in RRD with wholly detached macula.

Bruch's membrane opening-minimum rim width and visual field loss in glaucoma: a broken stick analysis.

AIM: To determine the Bruch's membrane opening-minimum rim width (BMO-MRW) tipping point where corresponding visual field (VF) damages become detectable. METHODS: A total of 85 normal subjects and 83 glaucoma patients (one eye per participant) were recruited for the study. All of the patients had VF examinations and spectral-domain optical coherence tomography to measure the BMO-MRW. Total deviation values for 52 VF points were allocated to the corresponding sector according to the Garway-Heath distribution map. To evaluate the relationship between VF loss and BMO-MRW measurements, a "broken-stick" statistical model was used. The tipping point where the VF values started to sharply decrease as a function of BMO-MRW measurements was estimated and the slopes above and below this tipping point were compared. RESULTS: A 25.9% global BMO-MRW loss from normative value was required for the VF loss to be detectable. Sectorally, substantial BMO-MRW thinning in inferotemporal sector (33.1%) and relatively less BMO-MRW thinning in the superotemporal sector (8.9%) were necessary for the detection of the VF loss. Beyond the tipping point, the slopes were close to zero throughout all of the sectors and the VF loss was unrelated to the BMO-MRW loss. The VF loss was related to the BMO-MRW loss below the tipping point. The difference between the two slopes was statistically significant (P≤0.002). CONCLUSION: Substantial BMO-MRW loss appears to be necessary for VF loss to be detectable in patients with open angle glaucoma with standard achromatic perimetry.

Vascular Displacement in Idiopathic Macular Hole after Single-layered Inverted Internal Limiting Membrane Flap Surgery.

PURPOSE: To compare vascular displacement in the macula after surgical closure of idiopathic macular hole (MH) after single-layered inverted internal limiting membrane (ILM) flap technique and conventional ILM removal. METHODS: This retrospective study included patients who underwent either vitrectomy and ILM removal only or vitrectomy with single-layered inverted ILM flap for idiopathic MH larger than 400 µm from 2012 to 2015. A customized program compared the positions of the retinal vessels in the macula between preoperative and postoperative photographs. En face images of 6 × 6 mm optical coherence tomography volume scans were registered to calculate the scale. Retinal vessel displacement was measured as a vector value by comparing its location in 16 sectors of a grid partitioned into eight sectors in two rings (inner, 2 to 4 mm; outer, 4 to 6 mm). The distance and angle of displacement were calculated as an average vector and were compared between the two groups for whole sectors, inner ring, outer ring, and for each sector. RESULTS: Twenty patients were included in the ILM flap group and 22 in the ILM removal group. There were no statistical differences between the groups for baseline characteristics. The average displacement in the ILM flap group and the ILM removal group was 56.6 µm at -3.4° and 64.9 µm at -2.7°, respectively, for the whole sectors (p = 0.900), 76.1 µm at -1.1° and 87.3 µm at -0.9° for the inner ring (p = 0.980), and 37.4 µm at -8.2° and 42.7 µm at -6.3° for the outer ring (p = 0.314). There was no statistical difference in the displacement of each of the sectors. CONCLUSIONS: Postoperative topographic changes showed no significant differences between the ILM flap and the ILM removal group for idiopathic MH. The single-layered ILM flap technique did not appear to cause additional displacement of the retinal vessels in the macula.

Functional end-arterial circulation of the choroid assessed by using fat embolism and electric circuit simulation.

The discrepancy in the choroidal circulation between anatomy and function has remained unsolved for several decades. Postmortem cast studies revealed extensive anastomotic channels, but angiographic studies indicated end-arterial circulation. We carried out experimental fat embolism in cats and electric circuit simulation. Perfusion defects were observed in two categories. In the scatter perfusion defects suggesting an embolism at the terminal arterioles, fluorescein dye filled the non-perfused lobule slowly from the adjacent perfused lobule. In the segmental perfusion defects suggesting occlusion of the posterior ciliary arteries, the hypofluorescent segment became perfused by spontaneous resolution of the embolism without subsequent smaller infarction. The angiographic findings could be simulated with an electric circuit. Although electric currents flowed to the disconnected lobule, the level was very low compared with that of the connected ones. The choroid appeared to be composed of multiple sectors with no anastomosis to other sectors, but to have its own anastomotic arterioles in each sector. Blood flows through the continuous choriocapillaris bed in an end-arterial nature functionally to follow a pressure gradient due to the drainage through the collector venule.

TOPOGRAPHIC CHANGES OF THE MACULA AFTER CLOSURE OF IDIOPATHIC MACULAR HOLE.

PURPOSE: To investigate retinal displacement in the macula after surgical closure of idiopathic macular hole and to identify factors correlated with displacement. METHODS: This retrospective multicenter study included 73 eyes of 73 patients having idiopathic macular hole. A custom program was developed to compare the position of the retinal vessels in the macula between preoperative and postoperative photographs. En face images of a 6 mm × 6 mm optical coherence tomography volume scans were registered to calculate the scale. A grid comprising 16 sectors in 2 rings (inner; 2-4 mm and outer; 4-6 mm) was superimposed. The displacement of the retinal vessels was measured as a vector value by comparing the location of the retinal vessels in each sector. The correlation between displacement and various clinical parameters was analyzed. RESULTS: The average displacement was 57.2 µm at an angle of -3.3° (nasal and slightly inferior). Displacement was larger in the inner ring (79.2 µm) than in the outer ring (35.3 µm, P < 0.001), and larger in the temporal sectors than in the corresponding nasal sectors (P ≤ 0.008). Inferior and superior displacement was noted in the superior and inferior sectors, respectively. Multiple regression analysis revealed that basal horizontal macular hole diameter and size of internal limiting membrane removal were independent factors of displacement. CONCLUSION: The macula was displaced centripetally, nasally, and slightly inferiorly after surgical closure of idiopathic macular hole. Hole closure, contraction of the nerve fiber layer, and gravity are the suggested mechanisms of macular displacement caused by internal limiting membrane peeling.