Aniseikonia and retinal morphological changes in eyes undergoing macular hole surgery.

Even after idiopathic macular hole (MH) surgery and with successful closure of MH, aniseikonia is a common postoperative symptom. We investigated the correlation of MH diameter, retinal displacement and retinal layer thicknesses with aniseikonia in 41 eyes of 41 patients undergoing MH surgery with internal limiting membrane peeling. Aniseikonia was measured with the New Aniseikonia Test. Retinal displacement (RD%) was defined as change of retinal distance between the temporal margin of the optic papilla and the intersection of the retinal vessels. Changes of thicknesses of the inner nuclear layer (INL%) and the outer retinal layer (OR%) were calculated. Aniseikonia improved postoperatively. Preoperative aniseikonia and their improvement at 6 months correlated with MH diameters (P = 0.004-0.046). Improvement of aniseikonia correlated with temporal RD% (P = 0.002-0.012). Improvement of vertical aniseikonia correlated with INL% at 2 weeks and with the nasal OR% at 1, 3, and 6 months (P = < 0.001-0.028). MH diameter and age were significant predictors for improvement of aniseikonia. The greater the temporal retina displacement, and the thinner the postoperative INL and OR, the greater the improvement of aniseikonia. MH diameter and age are strong predictors for improvement of aniseikonia after MH surgery.

Retinal Displacement after Scleral Buckle versus Combined Buckle and Vitrectomy for Rhegmatogenous Retinal Detachment: ALIGN Scleral Buckle versus Pars Plana Vitrectomy with Scleral Buckle.

PURPOSE: To assess the risk of retinal displacement after scleral buckle (SB) versus pars plana vitrectomy with SB (PPV-SB). DESIGN: Multicenter prospective nonrandomized clinical trial. METHODS: The study took place at VitreoRetinal Surgery in Minneapolis, Minnesota, Sankara Nethralaya in Chennai, India, and St. Michael's Hospital in Toronto, Canada from July 2019 to February 2022. Patients who underwent successful SB or PPV-SB for fovea-involving rhegmatogenous retinal detachment with gradable postoperative fundus autofluorescence (FAF) imaging were included in the final analysis. Two masked graders assessed FAF images 3 months postoperatively. Metamorphopsia and aniseikonia were assessed with M-CHARTs and the New Aniseikonia Test, respectively. The primary outcome was the proportion of patients with retinal displacement detected with retinal vessel printings on FAF in SB versus PPV-SB. RESULTS: Ninety-one eyes were included in this study, of which 46.2% (42 of 91) had SB and 53.8% (49 of 91) underwent PPV-SB. Three months postoperatively, 16.7% (7 of 42) in the SB group and 38.8% (19 of 49) in the PPV-SB group had evidence of retinal displacement (difference = 22.1%; odds ratio = 3.2; 95% confidence interval [CI], 1.2-8.6; P = 0.02) on FAF. The statistical significance of this association increased after adjustment for extent of retinal detachment, baseline logarithm of the minimum angle of resolution, lens status, and sex in a multivariate regression analysis (P = 0.01). Retinal displacement was detected in 22.5% (6 of 27) of patients in the SB group with external subretinal fluid drainage and 6.7% (1 of 15) of patients without external drainage (difference = 15.8%; odds ratio = 4.0; 95% CI, 0.4-36.9; P = 0.19). Mean vertical metamorphopsia, horizontal metamorphopsia (MH), and aniseikonia were similar between patients in the SB and PPV-SB groups. There was a trend to worse MH in patients with retinal displacement versus those without retinal displacement (P = 0.067). CONCLUSIONS: Scleral buckle is associated with less retinal displacement compared with PPV-SB, indicating that traditional PPV techniques cause retinal displacement. There is a trend toward increased risk of retinal displacement in SB eyes that underwent external drainage compared with SB eyes without drainage, which is consistent with our understanding that the iatrogenic movement of subretinal fluid, such as that which occurs intraoperatively during external drainage with SB, may induce retinal stretch and displacement if the retina is then fixed in the stretched position. There was a trend to worse MH at 3 months in patients with retinal displacement. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Aniseikonia and visual functions with optical correction and after refractive surgery in axial anisometropia.

PURPOSE: To evaluate differences in the subjective aniseikonia and stereoacuity in patients with axial anisometropia after full correction of the refractive error with spectacles, contact lenses, and refractive surgery. METHODS: A prospective study was performed in Cairo University Hospitals on 20 patients with axial anisometropia caused by unilateral myopia > 5 D with > 4 D inter-ocular difference in spherical equivalent who were suitable candidates for excimer laser ablation (LASIK) or implantable collamer lens implantation (ICL). All patients had measurement of best-corrected visual acuity (BCVA), fusion, stereoacuity, and magnitude of aniseikonia with spectacles, contact lenses, and after surgery. RESULTS: The mean age at time of surgery was 25.7 ± 3.1 years. There were no statistically significant differences in the BCVA or stereoacuity with spectacles, contact lenses, or after refractive surgery. Microkonia < 5%) was perceived with spectacles in 8 patients (40%) and remained unchanged in 7 of these 8 patients with contact lenses. Following LASIK (n = 11), there was an induced macrokonia < 2% in 4 patients (36%), persistent microkonia of 3% in 1 patient (9%), and no change in image size in 6 (55%) patients. Following ICL implantation (n = 9), there was a perceived macrokonia of 2% in 4 patients (44%), disappearance of microkonia in 1 patient (11%) and no change in 4 patients (44%). CONCLUSIONS: Differences in BCVA, stereoacuity, and aniseikonia after correction of anisometropia by glasses, contact lens and surgery are both clinically and statistically insignificant. Retinal or neural adaptation might have a role in correction for differences in image size.

Measuring aniseikonia tolerance range for stereoacuity - a tool for the refractive surgeon.

OBJECTIVE: No method exists to measure aniseikonia tolerance in stereoacuity. The brain can compensate for 2%-3% aniseikonia (i.e. 2-3 dioptres of anisometropia) without impairing stereoacuity; however, a substantial proportion of anisometropic patients experience problems caused by disruptions of sensory fusion due to surgically induced aniseikonia. We hypothesized that individual differences in tolerance to aniseikonia exist and sought to develop a method to measure aniseikonia tolerance. METHODS: A total of 21 eye-healthy phakic individuals older than 50 years of age and 11 patients awaiting clear lens extraction were included. Patients were tested with best corrected near and distance visual acuity, cover/uncover test, eye dominance test, stereoacuity threshold (TNO test), slit lamp examination and ocular coherence tomography. The stereoacuity threshold was determined with aniseikonia induced by different size lenses ranging from 1% to 9% magnification of both eyes in increments of 1%. The aniseikonia tolerance range (ATR) was defined as the percentage aniseikonia in which the stereoacuity threshold was maintained. RESULTS: We examined 32 patients with a median age of 65 (95% CI: 62-66 years), CDVA better than 6/7.5 (0.1 logMAR), and median near visual acuity better than 6/6 (0.0 logMAR). The median stereoacuity threshold was 60 arcsec (maximum 30, minimum 120). We observed large inter-individual differences in ATR: 6/31 (19%) participants had an ATR of ≤1%, 1/31 (3%) had an ATR of 1-5%, 7/31 (22%) had an ATR of 5-10%, and 17/31 (54%) had an ATR of >10%. CONCLUSION: We present a reliable method for measuring the amount of aniseikonia that a person can tolerate without impairing stereopsis. We report large inter-individual differences in tolerance of aniseikonia.

Changes in aniseikonia and influencing-factors following successful macula-off retinal detachment surgery.

This study investigated the changes in the severity of aniseikonia after surgery for macula-off retinal detachment (RD), and the relationship between aniseikonia and retinal microstructures. The study included 26 eyes of 26 patients undergoing RD surgery. Visual acuity was measured preoperatively, and at 3, 6, and 12 months postoperatively. Degree of aniseikonia and OCT images were obtained at 3, 6, and 12 months postoperatively. The aniseikonia values (mean ± standard deviation) at 3, 6, and 12 months postoperatively were -5.3 ± 4.2%, -4.4 ± 4.4%, and -3.1 ± 3.2%, respectively. Significant improvement was observed from 3 to 12 months postoperatively (P = 0.001). Twelve months postoperatively, 14 eyes had micropsia, 1 eye had macropsia, and 11 eyes were free of aniseikonia. Stepwise multiple regression analyses revealed that the severity of aniseikonia at 12 months postoperatively was significantly associated with postoperative development of cystoid macular edema (CME) and epiretinal membrane (ERM), as well as area of preoperative RD. In conclusion, although aniseikonia was gradually relieved after RD surgery during a 1-year follow-up period, approximately half of patients had aniseikonia and almost all of them had micropsia. Aniseikonia was associated with presence of postoperative CME, ERM, and area of preoperative RD.

[Clinical analysis of binocular anisei konia after laser in situ keratomileusis on myopic patients].

PURPOSE: To explore the effect produced by laser in situ keratomileusis (LASIK) on binocular aniseikonia(BA) and steropsis of myopic patients. METHODS: Sixty-four cases who received LASIK were divided into 4 groups by different binoeular diopter with the binocular aniserkonia (BA) designed by Liugeping and BA. The patients were tested on 6 months before and after the operation respectively for studing the relationship between the post-operative BA and steropsis. RESULTS: When the binocular diopter difference was < or = 2.5 D, there was no significant difference between the preoperative and postoperative BA. When the diopter difference was > 2.50 D, the incongruons images of simultaneous perception and stereoscopic vision after operation had significant divergence compared with those before the operation. The postoperative stereopsis was closely related to binocular vision. CONCLUSION: LASIK can not only reduce the BA of high myopic anisome tropia patients to a range that can be endured, but also be helpful to restore the stereopsis. Moreover, the better the postoperative binocular vision, the patients have the finer the stereopsis will be.

Closed-system technique for implantation of iris-supported negative-power intraocular lens.

BACKGROUND: The iris-supported claw lens can reversibly correct a wide range of ametropia and aniseikonia with excellent predictability and stability. However, concerns regarding its potential harm to the corneal endothelium have prevented its widespread use. Our experience with the closed-system surgical technique and the spreader device used in 180 cases between 1987 and 1993 has led us to conclude that potential complications are more likely due to the technique of implantation rather than to the properties of the lens itself. METHOD: We conducted a prospective study of 35 eyes of 20 consecutive patients (mean age, 38 years; range, 21 to 55 years) operated on between August 1993 and August 1994. Preoperative spherical equivalent refractions ranged from -6.00 to -21.25 diopters (D) (mean, -12.50 D). Follow up was 6 months (86% of eyes) to 1 year (57% of eyes). Spectacle-corrected visual acuity and endothelial cell density were measured prior to, and 1, 6, and 12 months following lens implantation. All data were analyzed using the paired t-test. RESULTS: Mean endothelial cell density dropped insignificantly (p > .10):by 1.22% at 1 month (n = 34), by 2.25% at 6 months (n = 27), and by 1.21% at 12 months (n = 18). Spectacle-corrected visual acuity increased significantly (p < .001): from a mean of 0.61 preoperatively to 0.77 at 1 month, 0.84 at 6 months, and 0.93 at 12 months postoperatively. At 12 months, 15 eyes (75%) had a refraction within +/-0.50 D, 19 eyes (95%) within +/-1.00 D, and 20 eyes (100%) within +/-2.00 D of emmetropia. CONCLUSIONS: Our results suggest that the closed-system approach using the spreader device allows safe implantation of the Worst iris-supported claw lens.

Eleven-year experience with radial keratotomy.

1,900 consecutive eyes that underwent radial keratotomy by the senior author were evaluated retrospectively. 3 months after surgery, minimum reduction in mean spherical equivalent of 0.67D was achieved with 1 incision and maximum 7.25D with 24 incisions. Uncorrected visual acuity of 20/40 or better was obtained in 99.4% of eyes with low myopia, 64.2% with moderate myopia and 32.4% with high myopia. For anisometropia, bilateral RK reduced refractive error from -12. 12D to -5. 22D in more myopic eyes and -8. 18D to -3. 4D in less myopic eyes and unilateral surgeries reduced refractive error from -9. 45D to -3. 85D. Anisometropia after surgery became clinically and physically acceptable and aniseikonia was significantly improved. No vision threatening complications occurred. Our results indicate that radial keratotomy is a relatively safe and effective surgical procedure for myopia.

The ultrastructure of well-healed lenticules in keratomileusis.

Two well-healed hyperopic keratomileusis homoplastica lenticules, one 4 years old, the other 5 months old, were removed from the same patient following postoperative complications of triplopia and aniseikonia. The lenticules were examined by light and electron microscopy. Both lenticules were repopulated with keratocytes throughout the lamellae. Degenerated keratocytes were observed in the 5-month-old lenticule and recipient stroma, and in the 4-year-old lenticule; no degenerated keratocytes were seen in the recipient stroma of the 4-year-old lenticule. These findings may have resulted from toxic constituents of the solutions used to preserve the donor cornea. The basement membrane was thickened in both lenticules. The epithelial cell layer was irregular in the periphery of the lenticule where Bowman's membrane was disrupted. These findings suggest that careful surgical technique that minimizes damage to Bowman's layer and basement membrane may promote more rapid epithelial healing. The histologic results suggest that the cause of this patient's triplopia was irregular astigmatism.