A novel vector field analysis for quantitative structure changes after macular epiretinal membrane surgery.

The aim of this study was to introduce novel vector field analysis for the quantitative measurement of retinal displacement after epiretinal membrane (ERM) removal. We developed a novel framework to measure retinal displacement from retinal fundus images as follows: (1) rigid registration of preoperative retinal fundus images in reference to postoperative retinal fundus images, (2) extraction of retinal vessel segmentation masks from these retinal fundus images, (3) non-rigid registration of preoperative vessel masks in reference to postoperative vessel masks, and (4) calculation of the transformation matrix required for non-rigid registration for each pixel. These pixel-wise vector field results were summarized according to predefined 24 sectors after standardization. We applied this framework to 20 patients who underwent ERM removal to obtain their retinal displacement vector fields between retinal fundus images taken preoperatively and at postoperative 1, 4, 10, and 22 months. The mean direction of displacement vectors was in the nasal direction. The mean standardized magnitudes of retinal displacement between preoperative and postoperative 1 month, postoperative 1 and 4, 4 and 10, and 10 and 22 months were 38.6, 14.9, 7.6, and 5.4, respectively. In conclusion, the proposed method provides a computerized, reproducible, and scalable way to analyze structural changes in the retina with a powerful visualization tool. Retinal structural changes were mostly concentrated in the early postoperative period and tended to move nasally.

Plasma Antiretinal Autoantibody Profiling and Diagnostic Efficacy in Patients With Autoimmune Retinopathy.

PURPOSE: To evaluate plasma antiretinal autoantibody (ARA) profiling and diagnostic efficacy for autoimmune retinopathy (AIR). DESIGN: A multicenter, diagnostic evaluation study. METHODS: Forty-nine patients with a clinical diagnosis of AIR, disease controls including 20 patients with retinitis pigmentosa (RP), and 30 normal controls were included. Plasma samples from patients were analyzed for the presence of 6 ARAs, including recoverin, α-enolase, carbonic anhydrase II, heat shock protein 60, aldolase C, and cone-rod homeobox/cone-rod retinal dystrophy 2 using western blotting. RESULTS: Autoantibody detection rates against cone-rod homeobox/cone-rod retinal dystrophy 2, heat shock protein 60, and aldolase C in AIR were 67.3%, 40.8%, and 42.9%, respectively, which were higher than those in RP and normal controls (P < .001, P < .001, and P = .007, respectively), but recoverin, α-enolase, and carbonic anhydrase II were not different from other control groups (P = .117, P = .774, and P = .467, respectively). Among ARAs, antirecoverin antibody was the most specific, as it was found in 3 (6.1%) patients with AIR and none of the control groups. As the number of detected ARAs increased, the probability of AIR increased (odds ratio: 1.913; P < .001; 95% confidence interval: 1.456-2.785). The positive number of ARAs was significantly higher when photoreceptor disruption was observed on optical coherence tomography, or severe dysfunction was observed in electroretinography (P = .022 and P = .029, respectively). CONCLUSIONS: The profiles of ARAs in the AIR group were different from those in the RP and normal controls. The higher number of positive ARAs suggests a higher possibility of AIR diagnosis. ARAs should be used as adjunct tools for the clinical diagnosis of AIR.

NASAL CROWDING AND NASAL TILTING OF THE MACULA AFTER EPIRETINAL MEMBRANE SURGERY.

PURPOSE: To identify postoperative macula deviation after epiretinal membrane surgery and to investigate its clinical effects. METHODS: Patients who underwent idiopathic epiretinal membrane removal and followed up for >12 months were enrolled. Macular deviation was evaluated using disk margin-to-fovea distance, foveal angle, and horizontal and vertical asymmetry of retinal thickness and volume. Horizontal or vertical asymmetry was defined as percentile asymmetry between nasal and temporal quadrants or between superior and inferior quadrants, respectively. The association between macular deviation parameters and best-corrected visual acuity and metamorphopsia were evaluated. Baseline and postoperative parameters were compared depending on epiretinal membrane severity. RESULTS: Data from 102 eyes with a mean follow-up of 21.14 months were analyzed. Disk margin-to-fovea distance and foveal angle decreased with time and horizontal asymmetry of thickness and volume increased with time, showing nasal crowding and nasal tilting. Postoperative changes of disk margin-to-fovea distance and horizontal asymmetry were associated with best-corrected visual acuity. Severe epiretinal membrane eyes showed greater postoperative nasal deviation than mild epiretinal membrane eyes. CONCLUSION: Postoperative nasal crowding and tilting was quantitatively identified. The causative layers for nasal deviation might be the inner retinal layers, as the foveal angle decreased with time. Postoperative disk margin-to-fovea distance shortening and nasal-deviated horizontal asymmetry were correlated with best-corrected visual acuity improvement.

Surgical outcomes of unilateral lateral rectus recession versus recess-resect in children with convergence insufficiency type intermittent exotropia.

To determine the efficacy of unilateral lateral rectus recession (ULR) for convergence insufficiency-type intermittent exotropia (CI-type IXT), we compared surgical outcomes following ULR and recess‒resect (RR) procedures for CI-type IXT. In this retrospective study, medical records of 57 children who underwent ULR (n = 30) or RR (n = 27) for CI-type IXT of less than 25 PD at distance with a postoperative follow-up of 6 months or more were reviewed. Surgical success was defined as an alignment between 10 PD exodeviation and 5 PD esodeviation at distance and near fixation. The postoperative exodeviation showed no significant difference between the two groups at the last follow-up. A significant reduction in the mean near-distance difference was achieved postoperatively in both groups: from 5.4 PD preoperatively to 2.5 at last follow-up after ULR, and from 8.2 to 2.4 after RR (both p = 0.001). However, this difference between ULR and RR was not statistically significant (p > 0.05). The success rate at the last follow-up was 63.3% for ULR and 70.4% for RR (p = 0.574). ULR was found to be an effective treatment for CI-type IXT, with similar surgical outcomes to RR.

Comparison of clinical usefulness of central 30-2 and 24-2 threshold tests using SITA strategy.

PURPOSE: To compare the clinical utilities of the SITA-based central 24-2 and 30-2 threshold tests. METHODS: Three hundred sixty-five (365) eyes of 183 glaucoma and glaucoma suspect patients who had undergone both central 30-2 and 24-2 threshold testing using the Swedish interactive threshold algorithm (SITA) standard strategy were retrospectively reviewed. The tests were performed in patients with a minimum visual acuity of LogMAR best-corrected visual acuity (BCVA) 0.3. We compared test time, fixation loss (%), false-positive error rate (%), and false-negative error rate (%), all of which are indices of reliability. We additionally compared the mean deviation (MD), pattern standard deviation (PSD), and visual field index (VFI), all of which are indices of the visual field test. RESULTS: The mean age was 54.67 ± 14.95. MD, VFI, and fixation loss showed no significant difference between the 30-2 and 24-2 tests. As expected, 24-2 was shorter in duration: 5.64 ± 1.09 min versus 7.51 ± 1.38 min (p < .001), a 24.51 ± 9.45% difference. The false-positive error rate was significantly higher, but the false-negative error rate was lower, with the 24-2 threshold test (p = .009, p < .001). The PSD also was lower with 24-2 than with 30-2 (p < .001). CONCLUSION: The two tests' VFI and MD are comparable. The 24-2 test may be a more efficient examination for most patients in terms of test time. In the other relevant aspects, the two tests are not identical. Therefore, it would be advisable to tailor visual field testing to the individual patient.

Surgical outcomes of intermittent exotropia according to exotropia type based on distance/near differences.

We compare the surgical outcomes of intermittent exotropia of the basic, pseudo-divergence excess (pseudo-DE) and true divergence excess (true DE) types. A study was performed with 342 patients who had undergone surgery for intermittent exotropia of the basic, pseudo-DE or true DE type with a postoperative follow-up period of 6 months or more. The main outcome measures were postoperative angles of deviation at distance and near, and surgical success rates. Surgical success was defined as alignment between exodeviation of 10 PD and esodeviation of 5 PD at distance and near. Additionally, survival curves of recurrence were analyzed by the Kaplan-Meier method. The postoperative angles of deviation at both distance and near in pseudo-DE type were significantly smaller than those in basic type at the final examination (p = 0.003, <0.001). The final surgical success rate in pseudo-DE (70.2%) was better than in basic (46.3%) or true DE (28.6%) (p = 0.003, 0.01). Reoperation for recurrent exotropia was performed in 27% of the basic, 17% of the pseudo-DE, and 35.7% of the true DE cases. According to a survival analysis for recurrence, patients with pseudo-DE showed lower incidence of recurrence than did patients with basic and true DE (p = 0.003, 0.02). In conclusion, the patients with intermittent exotropia of the pseudo-DE type showed better surgical outcomes than those with the basic or true DE type. Pseudo-DE also showed a lower recurrence rate than did the other 2 groups.

Utility of the optical quality analysis system for decision-making in cataract surgery.

BACKGROUND: A cataract is a common cause of vision impairment that requires surgery in older subjects. The Optical Quality Analysis System (OQAS, Visiometrics SL, Terrassa, Spain) assesses the optical quality of the eye in cataract patients. This study shows the role of the optical quality evaluation system for decision-making in cataract surgery. We investigated the clinical utility of the OQAS for decision-making in cataract surgery. METHODS: Sixty-seven eyes from 67 patients undergoing cataract surgery and 109 eyes from 109 control subjects were compared. The best corrected visual acuity (BCVA) was measured. The objective scatter index (OSI), modulation transfer function (MTF), Strehl ratio, predicted visual acuity (PVA) 100%, PVA 20%, and PVA 10% were measured using the OQAS. The sensitivity and specificity of the different parameters were analyzed using the receiver operating characteristic (ROC) curve. The main parameters measured were sensitivity and specificity. RESULTS: The BCVA, OSI, PVA 100%, PVA 20%, and PVA 10% were higher in the cataract group compared to those in the control group, while the MTF and Strehl ratios were lower (p <  0.001 for all). ROC analysis showed that the OSI had the largest area under the curve and that the sensitivity and specificity of the OSI were 83.9 and 84.6%, respectively, at the optimal cut-off point of 2.35. CONCLUSION: The MTF, OSI, Strehl ratio, PVA 100%, PVA 20% and PVA 10% may be useful parameters for preoperative decision-making in cataract surgery. The OSI appears to be the most effective parameter for this purpose.

Postoperative changes of intermittent exotropia type as classified by 1-hour monocular occlusion.

PURPOSE: To evaluate postoperative changes of the intermittent exotropia type as classified by 1-hour monocular occlusion test. DESIGN: Institutional, retrospective study. METHODS: We retrospectively reviewed the medical records of 179 patients who had undergone surgery for intermittent exotropia with a postoperative follow-up of 6 months or more. We evaluated the exodeviation obtained before and after 1-hour monocular occlusion preoperatively and again at postoperative 1, 3 and 6 months. Intermittent exotropia was divided into 4 types according to Burian's classification. The main outcome measure was the distribution of intermittent exotropia type based on 1-hour monocular occlusion in both pre- and postoperative periods. RESULTS: Of the 179 patients, 152 (84.9%) were assigned preoperatively to the basic type, 14 (7.8%) to the pseudo-divergence excess type, and 13 (7.8%) to the convergence insufficiency type. At postoperative 1, 3, and 6 months, the exotropia-type distribution was shifted predominantly to the basic type (p<0.001, p = 0.004, p = 0.029, respectively). Among the preoperative basic-type patients, 96.9% maintained that type postoperatively. However, only 18.2 and 11.1% of the pseudo-divergence excess and convergence insufficiency types maintained the same type. The proportions of the basic type had increased at postoperative 6 months, from 87.8 to 95.7% for bilateral lateral rectus (BLR) recession, from 73.7 to 92.3% for unilateral recess-resect (R&R), and from 88.0 to 95.0% for unilateral lateral rectus (ULR) recession. CONCLUSION: The type of intermittent exotropia changed mostly to the basic type postoperatively even as classified after 1-hour monocular occlusion. This finding was consistent regardless of the surgical methods (BLR, ULR recession and R&R).

Changes of corneal topographic measurements and higher-order aberrations after surgery for exotropia.

PURPOSE: To analyze changes in corneal topographic measurements and higher-order aberrations (HOAs) after horizontal muscle surgery for exotropia. DESIGN: Retrospective, observational study. METHODS: A total of 131 eyes of 121 patients who had undergone surgery for exotropia were included. The eyes with unilateral lateral rectus (ULR) or bilateral lateral rectus (BLR) recession(s) were assigned to group A, and those with unilateral lateral rectus recession & medial rectus resection (R&R) to group B. Corneal topographic measurements and HOAs were compared between the preoperative and postoperative periods using a Placido-dual Scheimpflug analyzer (Galilei 2TM, Ziemer, Port., Switzerland) for each group. RESULTS: In group A, simulated keratometery (sim K) was significantly changed until 3 months postoperatively relative to the preoperative value (postoperative 1 week, p = 0.017; 1 month, p = 0.037; and 3 months, p = 0.023, respectively). All steep K (steep sim K, steep-Kpost, and TCP-steep K) parameters also were significantly changed at postoperative 1 month (p<0.001, p = 0.015, p<0.001, respectively), but not at 3 months. Among the higher-order aberrations, spherical aberration (Z40) and secondary horizontal astigmatism (Z42) at postoperative 1 week had significantly changed from the preoperative values, as had horizontal quadrafoil (Z44) at 1 month. However, in group B, only vertical quadrafoil (Z4-4) showed statistically significant changes, at postoperative 1 and 3 months. None of the other postoperative parameters was significantly different from the corresponding preoperative value. CONCLUSION: Lateral rectus recession induced changes in both corneal topographic measurements and HOAs, whereas R&R did so only in HOAs. These changes might explain some patients' complaints about poor quality of vision.

Effect of combining inferior oblique muscle weakening procedures with exotropia surgery on the surgical correction of exotropia.

PURPOSE: To determine whether the inferior oblique (IO) muscle weakening procedure combined with exotropia surgery affects the surgical correction of exotropia. DESIGN: Institutional, retrospective study. METHODS: We retrospectively reviewed the medical records of 310 patients who had undergone exotropia-correcting surgery combined with IO weakening (group A, 64 patients) or without IO weakening (group B, 246) with a postoperative follow-up of 6 months or more. The main outcome measures were the postoperative mean angle of horizontal deviation, the success rate, and the overcorrection rate. Surgical success was defined as an alignment between 10 prism diopters (PD) of exodeviation and 5 PD of esodeviation. RESULTS: The postoperative mean angles of exodeviation, throughout the follow-up period, did not significantly differ between the groups. Although the surgical success rate was higher in group B at postoperative 1 month (p = 0.035), there was no statistical difference between the 2 groups from postoperative 6 months.: The final success rates were 56.3 and 51.6% (p = 0.509). The overcorrection rate was significantly higher in group A at postoperative 1, 6 and 24 months (p = 0.017, p = 0.028, p = 0.030, respectively); however, at the final follow-up, there was no overcorrection in either group. CONCLUSION: The overcorrection rate was higher in group A until postoperative 2 years, even though the mean angles of exodeviation and the success rates did not significantly differ between the 2 groups. Surgeons should be mindful of overcorrection when planning exotropia surgery combined with the IO weakening procedure.

Early postoperative changes of motor alignment after surgery for intermittent exotropia.

PURPOSE: To evaluate the early postoperative changes of the angle of deviation after surgery for intermittent exotropia. METHODS: We retrospectively reviewed the medical records of 114 patients who had been surgically treated for intermittent exotropia and followed-up on postoperatively for 1 month or more. Patients were observed at postoperative 6 h, 1 day, 1 week, and 1 month. The main outcome measure was the change of the angle of deviation during the early postoperative period (from 6 h to 1 day postoperatively). RESULTS: The mean preoperative angle of exodeviation was 26.3 ± 7.6 PD at distance and 25.4 ± 10.3 PD at near. The angle of deviation was -3.3 (esodeviation) ± 7.0 PD at distance and -0.7 ± 7.1 PD at near at postoperative 6 h, and -3.7 ± 6.9 PD and -0.8 ± 6.8 PD at postoperative 1 day. Neither of these sets represented a significant change from 6 h to 1 day postoperatively (p = 0.300 at distance, p = 0.945 at near). However, in 25 patients (21.9%) the angle of deviation changed 5 PD or more from 6 h to 1 day. Among them, ten showed exodrift and 15 esodrift. At postoperative 1 month, the deviations became significantly more exotropic compared with postoperative 1 day (p < 0.001). CONCLUSIONS: The mean angle of deviation showed no significant change from 6 h to 1 day postoperatively, but 21.9% of patients showed a change of 5 PD or more in this period. These results should be considered in determining the time and the target angle of adjustment in adjustable strabismus surgery for exotropia.

Influence of Myopia on Size of Optic Nerve Head and Retinal Nerve Fiber Layer Thickness Measured by Spectral Domain Optical Coherence Tomography.

PURPOSE: To investigate optic nerve head size and retinal nerve fiber layer (RNFL) thickness according to refractive status and axial length. METHODS: In a cross-sectional study, 252 eyes of 252 healthy volunteers underwent ocular biometry measurement as well as optic nerve head and RNFL imaging by spectral-domain optical coherence tomography. Correlation and linear regression analyses were performed for all subjects. The magnification effect was adjusted by the modified axial length method. RESULTS: Disc area and spherical equivalent were positively correlated (r = 0.225, r2 = 0.051, p = 0.000). RNFL thickness showed significant correlations with spherical equivalent (r = 0.359, r2 = 0.129, p = 0.000), axial length (r = -0.262, r2 = 0.069, p = 0.000), disc radius (r = 0.359, r2 = 0.129, p = 0.000), and radius of the scan circle (r = -0.262, r2 = 0.069, p = 0.000). After adjustment for the magnification effect, those relationships were reversed; RNFL thickness showed negative correlation with spherical equivalent and disc radius, and positive correlation with axial length and radius of the scan circle. The distance between the disc margin and the scan circle was closely correlated with RNFL thickness (r = -0.359, r2 = 0.129, p = 0.000), which showed a negative correlation with axial length (r = -0.262, r2 = 0.069, p = 0.000). CONCLUSIONS: Optic disc radius and RNFL thickness decreased in more severely myopic eyes, but they increased after adjustment for magnification effect. The error due to the magnification effect and optic nerve head size difference might be factors that should be considered when interpreting optical coherence tomography results.

Vitamin D Supplementation for Patients with Dry Eye Syndrome Refractory to Conventional Treatment.

This study investigated the effect of vitamin D supplementation in patients with dry eye syndrome (DES) refractory to conventional treatment with vitamin D deficiency. A total of 105 patients with DES refractory to conventional treatment and vitamin D deficiency that was treated with an intramuscular injection of cholecalciferol (200,000 IU). Serum 25-hydroxyvitamin D (25(OH)D) levels were measured. Eye discomfort was assessed using ocular surface disease index (OSDI) and visual analogue pain score (VAS). Tear break-up time (TBUT), fluorescein staining score (FSS), eyelid margin hyperemia, and tear secretion test were measured before treatment, and 2, 6, and 10 weeks after vitamin D supplementation. Mean serum 25(OH)D level was 10.52 ± 4.61 ng/mL. TBUT, and tear secretion test showed an improvement at 2 and 6 weeks after vitamin D supplementation compared to pretreatment values (p < 0.05 for all, paired t-test). Eyelid margin hyperemia and the severity of symptoms showed improvement at 2, 6, and 10 weeks after vitamin D supplementation (p < 0.05 for all). Compared to pre-treatment values, FSS, OSDI and VAS were decreased at 2 weeks (p < 0.05 for all). In conclusion, vitamin D supplementation is effective and useful in the treatment of patients with DES refractory to conventional treatment and with vitamin D deficiency.

Low Serum 25-Hydroxyvitamin D Levels Are Associated with Dry Eye Syndrome.

BACKGROUND: Dry eye syndrome (DES) is a common tear film and ocular surface disease that results in discomfort, visual disturbance, and tear film instability with potential damage to the ocular surface. Systemic diseases associated with DES include diabetes mellitus, rheumatoid arthritis, depression, anxiety, thyroid disease, allergic diseases, irritable bowel syndrome, chronic pain syndrome, and hyperlipidemia. Interestingly, it has been found that most of these are associated with low levels of serum 25-hydroxyvitamin D (25(OH)D) or inadequate sunlight exposure. METHODS: In this cross-sectional data analysis, noninstitutionalized adults aged ≥19 years (N = 17,542) who participated in Korean National Health and Nutrition Examination Survey 2010-2012 were included. Information regarding duration of sunlight exposure was collected from the survey participants. Serum 25(OH)D and zinc levels were measured. The confounding variables were age, gender, sunlight exposure time, region of residence, obesity, serum 25(OH)D level, diabetes mellitus, rheumatoid arthritis, depression, thyroid disorder, atopic dermatitis, history of ocular surgery, regular exercise, and walking exercise. RESULTS: Mean serum 25(OH)D levels of subjects with and without DES were 16.90 ± 6.0 and 17.52 ± 6.07 (p<0.001). Inadequate sunlight exposure time (odds ratio [OR], 1.554; 95% confidence interval [CI], 1.307-1.848), urban residence (OR, 1.669; 95% CI, 1.456-1.913), indoor occupation (OR, 1.578; 95% CI, 1.389-1.814), and low serum 25(OH)D level (OR, 1.158; 95% CI, 1.026-1.308) were the risk factors for DES. After adjusting for age, sex, obesity, diabetes mellitus, rheumatoid arthritis, depression, thyroid disorder, atopic dermatitis, history of ocular surgery, regular exercise, and occupation, low serum 25(OH)D level (OR, 1.178; 95% CI, 1.010-1.372) and deficient sunlight exposure time (OR, 1.383; 95% CI, 1.094-1.749) were the risk factors for diagnosed DES. CONCLUSION: Low serum 25(OH)D levels and inadequate sunlight exposure are associated with DES in Korean adults. These results suggest that sufficient sunlight exposure or vitamin D supplementation may be useful in DES treatment.