Associations Between Visual Functions and Severity Gradings, Corneal Scatter, or Higher-Order Aberrations in Fuchs Endothelial Corneal Dystrophy.

Purpose: The purpose of this study was to investigate the associations between visual function and severity grading, corneal scatter, or higher-order aberrations (HOAs) in patients with Fuchs endothelial corneal dystrophy (FECD). Methods: This observational case series study included 49 eyes of 27 patients with FECD and 10 eyes of 10 healthy individuals. We evaluated corrected distance visual acuity (CDVA) using Landolt-C and Early Treatment Diabetic Retinopathy Study charts and contrast sensitivity using the CSV-1000E chart and CSV-1000RN letter chart. We analyzed the associations between visual function and explanatory variables, including age, modified Krachmer grade, central corneal thickness (CCT), anterior segment optical coherence tomography (AS-OCT)-based grade, HOAs, intraocular straylight, and corneal densitometry. We additionally conducted receiver operating characteristic (ROC) analysis to identify the corneal densitometry thresholds for decreased visual function. Results: There were significant associations between visual function and the modified Krachmer grade, CCT, AS-OCT-based grade, HOAs, intraocular straylight, and corneal densitometry. A modified Krachmer grade ≥ 3 was identified as a threshold for decreased visual function. Multivariate analysis showed that corneal densitometry was significantly associated with all visual function parameters, and HOAs were significantly associated with CDVA but not with contrast sensitivity. ROC analysis revealed that corneal densitometry of the posterior layer at 0 to 2 mm ≥ 10 grayscale units (GSU), was identified as a threshold for decreased visual function. Conclusions: HOAs, forward and backward light scatter affected visual function, with backward light scatter being the most influential. In patients with FECD, modified Krachmer grade ≥ 3 and corneal densitometry ≥ 10 GSU were thresholds for visual disturbance.

A Comprehensive Wavefront Assessment of Keratoconus Using an Integrated Scheimpflug Corneal Tomographer/Hartmann-Shack Wavefront Aberrometer.

OBJECTIVES: To characterize higher-order aberrations (HOAs) in different severities of keratoconus (KC) from the anterior and posterior corneal surfaces and whole eye using an integrated Scheimpflug corneal tomographer/Hartmann-Shack wavefront aberrometer. METHODS: This study included eyes with clinical KC, topographic KC (no clinical signs), fellow eyes with very asymmetric ectasia with normal topography and no clinical signs (VAE-NT), and control eyes. Corneal and ocular wavefront aberrations were obtained using an integrated Scheimpflug tomographer/Hartmann-Shack wavefront aberrometer. The diagnostic capability of distinguishing VAE-NT from the control was also tested. RESULTS: This study included 68 eyes with clinical KC, 44 with topographic KC, 26 with VAE-NT, and 45 controls. Clinical KC had significantly greater total HOAs and coma from the anterior and posterior corneal surfaces and whole eye than the other groups ( P <0.05). Although topographic KC had significantly greater values in all wavefront parameters than the control ( P <0.05), ocular and corneal HOAs did not differ between the VAE-NT and control groups. The coma from the anterior cornea in topographic KC was significantly greater than that in VAE-NT ( P <0.05); the coma from the posterior cornea and whole eye did not differ. Total HOAs from the anterior corneal surface exhibited the highest area under the receiver operating characteristic curve value of 0.774 (sensitivity, 73%; specificity, 78%). CONCLUSION: A comprehensive wavefront assessment can be used to quantitatively evaluate corneal and ocular HOAs across various severity of KC. Total HOAs from the anterior corneal surface exhibited the potential ability in distinguishing VAE-NT from the control eyes.

Intereye comparison of visual field progression in eyes with open-angle glaucoma.

PURPOSE: To investigate the intereye correlations between and differences in the rates of visual field (VF) progression in eyes with bilateral open-angle glaucoma. STUDY DESIGN: Retrospective, longitudinal, observational study. METHODS: Patients with bilateral open-angle glaucoma with 8 or more reliable 30 - 2 standard automated perimetry tests over a period of more than 2 years were enrolled. The rate of change of the MD (MD slope) was used as the indicator for the rates of VF progression. Descriptive statistics of the absolute intereye difference in the MD slope values were computed. Factors associated with a large intereye difference (> 0.42 dB/year) were explored. RESULTS: One hundred eighty-eight eyes from 94 patients (56 women) were enrolled. A significant intereye correlation of the rates of visual field progression (P = .002) was found. The mean ± standard deviation and median intereye differences of the MD slope values were 0.29 ± 0.31 and 0.18 dB/year (range: 0-1.41), respectively. The 5th, 10th, 25th, 75th, 90th, and 95th percentiles of intereye differences were 0.01, 0.02, 0.08, 0.42, 0.72, and 0.91 dB/year, respectively. Older age and slower progression were significantly associated with large intereye difference. CONCLUSION: A significant intereye correlation in the rate of VF progression was found in eyes with bilateral open-angle glaucoma. We showed the distributions and associated factors of intereye differences in VF progression. These data may be used for improving the estimation of rates of VF progression.

Optimizing correction of coma aberration in keratoconus with a novel soft contact lens.

PURPOSE: To report on a second-generation prototype contact lens (modified lens) with enhanced optics to correct coma aberration and compare its performance with that of the prototype contact lens (conventional lens) used to optimise correction of coma aberration in keratoconus (KC). METHODS: Both lenses were designed as a set of standardised soft contact lenses (SCLs) with asymmetric powers along the posterior surface. The modified lens differs from the conventional lens in that the optical zone is decentred superiorly by 0.7 mm. The on-eye performance was compared between the SCLs and no-lens wearing in terms of manifest refraction, corrected distance visual acuity (CDVA), ocular aberrations, subjective quality of vision, and on-eye lens position relative to the pupil. RESULTS: Thirty-four KC eyes were included. SCLs significantly decreased coma aberration compared to no-lens wear (none, 0.68 ± 0.27 µm; conventional lens, 0.37 ± 0.28 µm; modified lens, 0.19 ± 0.15 µm; P < 0.001), with the reduction in coma aberration being significantly greater with the modified lens than with the conventional lens (P = 0.018). No significant difference in manifest refraction or CDVA was found among the three conditions. Quality of vision was significantly better with the modified lens than with no SCL wear (P < 0.05) but no differences were found between the SCLs. The on-eye optical center position relative to the pupil was closer to the pupil centre using the modified lens than the conventional lens (P < 0.001). CONCLUSION: Optimisation of the location of the optical zone in a standardised asymmetric SCL improves correction of coma aberrations and on-eye optical centration.

Efficient measurements for the dynamic range of human lightness perception.

PURPOSE: Patients with an eye disease often report nyctalopia, hemianopia, and/or photophobia. We hypothesized that such symptoms are related to the disease impacting the dynamic range of lightness perception (DRL). However, there is currently no standardized approach for measuring DRL for clinical use. We developed an efficient measurement method to estimate DRL. STUDY DESIGN: Clinical trial METHODS: Fifty-five photophobic patients with eye disease and 46 controls participated. Each participant judged the appearance of visual stimuli, a thick bar with luminance that gradually changed from maximum to minimum was displayed on uniform background. On different trials the background luminance changed pseudo-randomly between three levels. The participants repeatedly tapped a border on the bar that divided the appearance of grayish white/black and perfect white/black. We defined the DRL as the ratio between the luminance values at the tapped point of the border between gray and white/black. RESULTS: The mean DRL of the patients was approximately 15 dB, significantly smaller than that of the controls (20 dB). The center of each patient's DRL shift depending on background luminance, which we named index of contextual susceptibility (iCS), was significantly larger than controls. The DRL of retinitis pigmentosa was smaller than controls for every luminance condition. Only the iCS of glaucoma was significantly larger than controls. CONCLUSIONS: This measurement technique detects an abnormality of the DRL. The results support our hypothesis that the DRL abnormality characterizes lightness-relevant symptoms that may elucidate the causes of nyctalopia, hemeralopia, and photophobia.

Quantification of accommodative response and visual performance in non-presbyopes wearing low-add contact lenses.

PURPOSE: Digital eye strain encompasses a range of ocular and visual symptoms across all age groups. Recently, symptoms associated with accommodative or binocular vision stress have become a major problem, especially in young individuals. The purpose of this prospective, single-blinded study was to objectively quantify the accommodative response and visual performance of low-add soft contact lenses (CLs) in young non-presbyopic individuals. METHODS: A daily disposable low-add bifocal design lens (low-add CL) was tested. It employs a centre-distance optical zone and peripheral zone with the added power of +0.50 D to support near vision. Sixteen subjects aged 20-39 years were enrolled in the study. Refractive state and accommodation were measured using an open-field autorefractor with three target vergences, namely, -0.20 D, -2.5 D, and -4.0 D. Binocular visual acuity at high (100%) and low (40%, 20%) contrast and reading ability were assessed. Monofocal soft CLs were used as controls. RESULTS: Accommodative response with low-add CLs was significantly smaller than those with two monofocal CL wearing conditions, i.e., at 40 cm (2.5 D of stimulus) and 25 cm (4.0 D of stimulus) (all p < 0.05). The 20% contrast visual acuity at distance was significantly better with low-add CLs and second-time monofocal CLs compared to first-time monofocal CLs (all p < 0.05). The reading ability was not significantly different. CONCLUSIONS: Quantification of accommodative response and visual performance demonstrated that using low-add CLs alleviated the accommodation under the near-vision condition, without sacrificing distance vision, in non-presbyopes.

Quantitative evaluation of visual function in patients with cornea verticillata associated with Fabry disease.

PURPOSE: To evaluate the visual function of patients with cornea verticillata associated with Fabry disease through quantitative evaluations of contrast sensitivity function and straylight. METHODS: We enrolled 28 eyes of 14 patients with Fabry disease (mean age, 37.1 ± 17.2  years) and 20 eyes of 20 age-matched healthy controls. Comprehensive ophthalmological examinations were performed and contrast sensitivity and letter contrast sensitivity were measured for all patients, following which the area under the log contrast sensitivity function (AULCSF) was calculated. Straylight was quantified using a straylight metre. Furthermore, subgroup analysis was performed according to the whorl-like pattern of cornea verticillata (mild and typical groups). RESULTS: All 28 eyes showed cornea verticillata. Visual acuity and letter contrast sensitivity values were the same for normal eyes and those with Fabry disease. AULCSF differed by 0.15 log[s] between the eyes with Fabry disease and the control eyes (p < 0.001), while straylight differed by 0.45 log[s] between the two groups (p < 0.001). Subgroup analysis based on the whorl-like pattern of cornea verticillata showed that AULCSF and straylight differed by 0.11 log[s] and 0.08 log[s], respectively, between the typical and mild groups (p = 0.036 and p = 0.147, respectively). CONCLUSION: Although cornea verticillata associated with Fabry disease does not affect the visual acuity and letter contrast sensitivity, more comprehensive testing of visual function by the inclusion of straylight and grating contrast sensitivity measurements shows clear functional deficits in these patients.

Fourier Analysis of Corneal Irregular Astigmatism Due to the Anterior Corneal Surface in Dry Eye.

OBJECTIVES: To evaluate corneal irregular astigmatism due to the anterior corneal surface using Fourier harmonic analysis with a Placido ring-based corneal topographer (Placido-based topographer) and three-dimensional anterior segment optical coherence tomography (OCT) in dry eyes. METHODS: Forty-four eyes of 44 subjects with dry eye and 20 eyes of 20 normal control subjects were enrolled. Corneal topographic data were obtained using a Placido-based topographer and OCT. Dioptric data from the central 3-mm zone of the anterior corneal surface were decomposed using Fourier harmonic analysis. Spherical, regular astigmatism, and irregular astigmatism (asymmetry and higher-order irregularity) refractive error components of the cornea from the two imaging modalities were compared. RESULTS: Both asymmetry and higher-order irregularity values were significantly greater in dry eyes than in control eyes for both the Placido-based topographer and OCT measurements (all P<0.05). In dry eyes, measured values of asymmetry and higher-order irregularities were significantly smaller when obtained with OCT than with the Placido-based topographer (both P<0.001). By contrast, these parameters were not significantly different between the two devices in control eyes. In dry eyes, severity of superficial punctate keratopathy in the central corneal region was correlated with irregular astigmatism. CONCLUSIONS: The amount of corneal irregular astigmatism, quantified using Fourier harmonic analysis, was significantly higher in dry eyes than in normal eyes. Measurements obtained with OCT and the Placido-based topographer differed in subjects with dry eyes. Therefore, caution should be practiced when trying to use these measurements interchangeably.

The Effect of Ocular Surface Regularity on Contrast Sensitivity and Straylight in Dry Eye.

Purpose: To investigate the association between visual function and ocular surface regularity in dry eye. Methods: We enrolled 52 eyes of 52 dry eye patients (34 dry eyes with superficial punctate keratopathy [SPK] in the central corneal region [central SPK] and 18 dry eyes without central SPK) and 20 eyes of 20 normal control subjects. All eyes had a best-corrected distance visual acuity better than 20/20. We measured two indices of contrast sensitivity function under photopic conditions: contrast sensitivity and letter contrast sensitivity. The area under the log contrast sensitivity function (AULCSF) was calculated from the obtained contrast sensitivity data. Straylight was quantified using a straylight meter. Results: Dry eyes with central SPK had significantly decreased contrast sensitivity function, including AULCSF and letter contrast sensitivity than those without central SPK and normal eyes (P < 0.05 for each). While the straylight values in both dry eye groups did not differ, straylight values were greater than those in normal eyes (P < 0.05 for both). In dry eye, the AULCSF and letter contrast sensitivity negatively correlated with the central SPK score (R = -0.485, P < 0.001, and R = -0.541, P < 0.001, respectively). Conclusions: In dry eye, reduced contrast sensitivity in part results from central SPK overlying the optical zone and the increased straylight results from tear film instability rather than central SPK.

Ocular forward light scattering and corneal backward light scattering in patients with dry eye.

PURPOSE: To evaluate ocular forward light scattering and corneal backward light scattering in patients with dry eye. METHODS: Thirty-five eyes in 35 patients with dry eye and 20 eyes of 20 healthy control subjects were enrolled. The 35 dry eyes were classified into two groups according to whether superficial punctate keratopathy in the central 6-mm corneal zone (cSPK) was present or not. Ocular forward light scattering was quantified with a straylight meter. Corneal backward light scattering from the anterior, middle, and posterior corneal parts was assessed with a corneal densitometry program using the Scheimpflug imaging system. RESULTS: Both dry eye groups had significantly higher intraocular forward light scattering than the control group (both P<0.05). The dry eye group with cSPK had significantly higher values in anterior and total corneal backward light scattering than the other two groups. Moderate positive correlations were observed between the cSPK score and corneal backward light scattering from the anterior cornea (R=0.60, P<0.001) and corneal backward light scattering from the total cornea (R=0.54, P<0.001); however, no correlation was found between cSPK score and ocular forward light scattering (R=0.01, P=0.932). CONCLUSIONS: Ocular forward light scattering and corneal backward light scattering from the anterior cornea were greater in dry eyes than in normal eyes. Increased corneal backward light scattering in dry eye at least partially results from cSPK overlying the optical zone.

Age-related changes of phoria myopia in patients with intermittent exotropia.

PURPOSE: To investigate the age-related changes in a myopic shift under binocular conditions (phoria myopia) in patients with intermittent exotropia (IXT). METHODS: Forty-five patients with IXT were studied: 21 were < or =9 years old (children), 11 were between 10 and 19 years (adolescents), and 13 were between 20 and 43 years (adults). The angle of strabismus was determined by the alternating prism cover test. The spherical refractive error was measured at 1 m using infrared video retinoscopy under monocular and binocular viewing conditions. RESULTS: The change in the spherical refractive error (DeltaR) between binocular and monocular conditions was significantly larger in adults (DeltaR = -1.11 +/- 1.01 diopters (D), average +/- standard deviation) than in children (DeltaR = -0.34 +/- 0.34 D; P < 0.05, analysis of variance). DeltaR was significantly correlated with the angle of exotropia only in adults (r = 0.55, P = 0.04). After strabismus surgery, DeltaR decreased in adults (n = 3). CONCLUSIONS: Because a significant myopic shift under binocular conditions was detected in IXT patients older than 20 years, phoria myopia can occur after age 20 even if functional disturbances are not observed in children or adolescent IXT patients, a fact that specialists need to bear in mind when treating younger patients.

Reading ability after macular translocation surgery with 360-degree retinotomy.

PURPOSE: To report reading ability using a standardized reading chart after macular translocation with 360-degree retinotomy in eyes with age-related macular degeneration (AMD) or with myopic choroidal neovascularization (mCNV). DESIGN: Interventional case series. METHODS: In 34 eyes of 34 patients with subfoveal choroidal neovascular membrane (AMD, 23; mCNV, 11), macular translocation surgery with 360-degree retinotomy and simultaneous extraocular muscle surgery were performed. The average age was 67.4 +/- 7.9 years, and the average follow-up period was 7.6 +/- 3.3 months. The best-corrected far visual acuity (FVA) was measured with a standardized visual acuity chart using Landolt Cs, and the critical print size (CPS) was determined with the Japanese version of the Minnesota reading chart (MNREAD-J Chart) preoperatively and postoperatively. Preoperative and postoperative change in the CPS was compared with the subjective visual improvement as assessed by a questionnaire. RESULTS: The postoperative improvement of FVA was statistically significant in eyes with mCNV (P =.010) but not significant in eyes with AMD (P =.495). The postoperative improvement of CPS was statistically significant both in eyes with AMD (P =.027) and in eyes with mCNV (P =.004). The subjective visual improvement was significantly correlated with the change of CPS in patients after a second better eye surgery. CONCLUSIONS: After macular translocation with 360-degree retinotomy, the improvement of reading ability was significant in eyes with both AMD and mCNV. We conclude that this surgical method is well suited to improve reading ability of patients with AMD or mCNV.