What Happens 20 to 30 years After Radial Keratotomy? Case Series.

ABSTRACT: Radial keratotomy (RK) was commonly performed in the 1980s and 1990s. We aimed to clarify the current status of post-RK refractive correction and treatment. We retrospectively reviewed the charts of 70 patients with a history of RK. Of the 70 patients, 44 were identified for clinical outcomes. Refractive or therapeutic intervention (rigid gas-permeable contact lens fit, spectacle prescription, corneal surgery, and use of pilocarpine hydrochloride for photophobia) was possible in 59% of patients with postoperative visual deterioration after RK; in the remaining 41%, therapeutic intervention was not possible. Rigid gas-permeable contact lens fit for corneal irregular astigmatism was the most common refractive intervention and was effective in 36% of cases in the university hospital.

Continuous Corneal Endothelial Damage by Chlorhexidine Alcohol Used for Disinfection in Nonophthalmic Surgery.

PURPOSE: To report a case of corneal endothelial damage caused by alcohol-containing chlorhexidine gluconate (CG-A) and its progression over time. METHODS: This was a case report. RESULTS: A 22-year-old man underwent neurosurgery under general anesthesia. CG-A (1%) was used for disinfection after the application of corneal protection tape. Postoperatively, the patient presented with hyperemia and swelling of the left conjunctiva and was referred to our department. Initial examination revealed left corneal epithelial erosion and corneal edema, which improved on postoperative day 14. The corneal endothelial cell density (ECD) was 3,345 cells/mm2 on day 14, decreased rapidly to 2,090 cells/mm2 on day 42, and slowly reduced to 1,122 cells/mm2 on day 168. Thereafter, no decrease in ECD was observed. CONCLUSIONS: CG formulations can lead to a persistent decrease in ECD over several months, even after improvement of acute corneal edema.

Comparison of Scheimpflug and Anterior Segment Optical Coherence Tomography Imaging Parameters for Japanese Patients With Fuchs Endothelial Corneal Dystrophy With and Without TCF4 Repeat Expansions.

PURPOSE: The aim of this study was to investigate the association between cytosine-thymine-guanine trinucleotide repeat (TNR) expansion in TCF4 and the clinical phenotypes of corneal densitometry or anterior segment morphology in Fuchs endothelial corneal dystrophy. METHODS: This retrospective cross-sectional study included 150 eyes from 75 Japanese consecutive patients with Fuchs endothelial corneal dystrophy. Cytosine-thymine-guanine repeat expansion of leukocyte-derived genomic DNA was analyzed through fragment analysis using polymerase chain reaction and triplet repeat primed polymerase chain reaction. Scheimpflug-based densitometry and anterior segment optical coherence tomography were applied. Corneal densitometry, and corneal and anterior segment morphology parameters were compared between patients with and without TNR expansion of 50 or more (expansion and nonexpansion groups, respectively) using a mixed model. RESULTS: The average age of the patients was 66.8 ± 13.0 years, and the modified Krachmer grading scale was 1, 2, 3, 4, 5, and 6 for 7, 32, 28, 51, 6, and 18 eyes, respectively. Sixteen patients (21%) exhibited ≥50 TNR expansion. No significant differences in sex, age, history of keratoplasty, modified Krachmer grade, and corneal densitometry in either diameter or depth were observed between the 2 groups. No significant differences in anterior segment morphology, including the anterior chamber depth and anterior chamber angle width parameters, were observed using a univariate mixed model, except for central corneal thickness (P = 0.047). However, according to the multivariate mixed model, repeat expansion was not significantly associated with central corneal thickness (P = 0.27). CONCLUSIONS: No significant differences in clinical phenotypes were found between Japanese patients having Fuchs endothelial corneal dystrophy with and without TNR expansion.

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.

Advances in Contact Lens Care Solutions: PVP-I Disinfectant and HAD Wetting Agents From Japan.

ABSTRACT: Half of the individuals who wear contact lenses use reusable lenses that require proper care. Improper contact lens (CL) care and using inadequate disinfecting solutions can lead to lens contamination, CL-related microbial keratitis, and Acanthamoeba keratitis. Oxidative disinfecting solutions, such as hydrogen peroxide, show higher efficacy than multipurpose solutions. Povidone-iodine (PVP-I), an oxidative disinfectant used in ophthalmic surgery, has been proven to be safe and effective. The PVP-I system, a CL disinfecting solution developed in Japan, has demonstrated excellent antimicrobial and antiviral properties. Although CL discomfort does not have a risk of ocular disorders with poor visual prognosis, such as keratitis, CL discomfort can still lead to lens dropout and thus needs to be addressed. To mitigate CL discomfort, it is essential to use disinfecting solutions containing surfactants and wetting agents that improve wettability of the lens surface. A CL solution containing hyaluronic acid derivatives (HADs) as wetting agents that permanently adhere to the lens surface to improve wettability of the lens surface was developed in Japan. There is potential for HAD to be integrated into various solutions. This article reviews the efficacy of novel PVP-I-based disinfecting solution and HAD wetting agents.

Optical Quality and Visual Performance With Different Toric Contact Lens Designs.

OBJECTIVES: To evaluate the optical quality of different toric contact lens (CL) designs and compare their on-eye visual correction performance. METHODS: Twenty soft CL wearers aged 20 to 39 years were enrolled. Two daily disposable silicone-hydrogel toric CLs were tested: the "Eyelid Stabilized Design" (ESD-CL) and prism-ballast design (PB-CL); a spherical daily disposable silicone hydrogel CL (spherical CL) was used as a control. On-eye performance was compared for corrected distance visual acuity (CDVA), astigmatism, and ocular higher-order aberrations (HOAs); astigmatism and ocular HOAs were measured with a wavefront sensor. The subjective quality of vision, rated for "blurred vision" and "double vision," lens rotation, and fitting were also compared. RESULTS: The ESD-CLs, PB-CL, and no-CL provided better CDVA than spherical CL ( P <0.05). Compared with spherical CL and no CL, PB-CL and ESD-CLs caused significantly lesser astigmatism ( P <0.05). Coma was significantly lesser with ESD-CLs than that with PB-CL ( P <0.05); total HOAs did not differ among the four conditions. The subjective ratings for blurred and double vision were significantly lower with ESD-CLs than those with spherical CL ( P <0.05). CONCLUSIONS: Toric CLs provide a better CDVA than spherical CLs. However, differences in coma and subjective symptoms may occur because of the design of toric CLs.

Long-Term Corneal Refractive Power Changes Two Decades After Radial Keratotomy With Microperforations.

ABSTRACT: We retrospectively examined corneal refractive power in three patients who had been followed up for more than 20 years after radial keratotomy (RK) with microperforations (MPs). All patients underwent RK in both eyes and were referred to our clinic because of postoperative decreased vision. MP was observed in five of the six eyes at the initial visit. The corneal refractive power of the anterior and posterior surfaces of the 6-mm-diameter cornea was examined using Fourier analysis based on corneal shape analysis using anterior segment optical coherence tomography. The spherical components decreased in all three cases. The asymmetry and higher-order irregularity components and fluctuations in corneal refractive power were markedly greater in the two cases with MP in both eyes. Fluctuations in corneal refractive power were observed at more than 20 years after RK with MP. Therefore, careful observation is necessary, even after a long-term postoperative follow-up period.

Comparison of Ocular Wavefront Aberration Measurements Obtained Using Two Hartmann-Shack Wavefront Aberrometers.

OBJECTIVES: To assess agreement between measurements of ocular wavefront aberrations obtained using the Pentacam AXL Wave (Oculus Optikgeräte GmbH) (Aberrometer A) and KR-1W (Topcon Corp) (Aberrometer B), both of which are based on the Hartmann-Shack principle. METHODS: In this prospective case-control study, ocular wavefront aberrations measurements were obtained using both aberrometers in patients with keratoconus (KC) and control participants. Ocular wavefront aberrations were measured through the natural pupil without dilation using both devices in a dark room. For both aberrometers, accommodation was inhibited by automatically adding fogging. The individual Zernike coefficients from the second to fourth order were compared between the two aberrometers for a 4-mm pupil diameter. RESULTS: Twenty-six KC and 29 control eyes were assessed. Statistically significant correlations ( P <0.05) were observed for all Zernike coefficients, except for Z 4-2 in the control group. Bland-Altman analysis indicated good agreement between aberrometers and no statistically significant differences in the control group. However, in the KC group, patterns of proportional error were observed in vertical coma Z 3-1 (r=0.338, P =0.008), trefoil Z 4-4 (r=0.701, P =0.003), secondary astigmatism Z 4-2 (r=0.348, P =0.025), and spherical aberrations Z 40 (r=0.407, P =0.012). CONCLUSIONS: The Zernike coefficient values measured by the two aberrometers were well correlated in the control and KC groups. However, in eyes with KC, Aberrometer B tended to present greater values in several Zernike coefficients than Aberrometer A, suggesting that wavefront measurements obtained using the two aberrometers are not interchangeable in patients with KC.

Evaluating the Differences Between Fluorescein Tear Break-up Time and Noninvasive Measurement Techniques.

OBJECTIVES: To compare fluorescein tear break-up time (BUT) and noninvasive BUT measured using interferometry and corneal topography. METHODS: We investigated 34 eyes of 34 patients with dry eye (mean age 39.2±8.3 years) and 16 eyes of 16 non-dry eye subjects (33.5±6.5 years). Tear film stability was measured using fluorescein BUT, noninvasive BUT (NIBUT)-DR1 with an interferometer, and noninvasive keratographic BUT (NIKBUT)-first and average using corneal topography. Correlations between fluorescein BUT and noninvasive BUT parameters were determined statistically. The noninvasive BUTs were compared between the dry eye and non-dry eye groups. The agreement between fluorescein and noninvasive BUTs was described using Bland-Altman analysis. RESULTS: Fluorescein BUT was significantly correlated with NIBUT-DR1, NIKBUT-first, and NIKBUT-average. The Bland-Altman analysis revealed bias and 95% limits of agreement between fluorescein BUT and noninvasive BUTs as follows: NIBUT-DR1: 2.07 s, -5.33 to 9.46 s; NIKBUT-first: 3.39 s, -5.46 to 12.24 s; NIKBUT-average: 6.61 s, -1.58 to 14.79 s. The noninvasive BUTs were significantly different between the two groups. When NIBUT-DR1, NIKBUT-first, and NIKBUT-average with Bland-Altman correction were used as an index for dry eye, the cut-off values were 7.1, 8.4, and 11.6 s, respectively. The sensitivities were 0.735, 0.818, and 0.727 and specificities were 0.500, 0.437, and 0.562, respectively. CONCLUSION: Fluorescein BUT and noninvasive BUTs were significantly correlated, and noninvasive BUTs had higher values than fluorescein BUT. Considering the differences between fluorescein BUT and noninvasive BUTs, noninvasive methods can be used as effective tool for diagnosing dry eye.

Optimized Artificial Intelligence for Enhanced Ectasia Detection Using Scheimpflug-Based Corneal Tomography and Biomechanical Data.

PURPOSE: To optimize artificial intelligence (AI) algorithms to integrate Scheimpflug-based corneal tomography and biomechanics to enhance ectasia detection. DESIGN: Multicenter cross-sectional case-control retrospective study. METHODS: A total of 3886 unoperated eyes from 3412 patients had Pentacam and Corvis ST (Oculus Optikgeräte GmbH) examinations. The database included 1 eye randomly selected from 1680 normal patients (N) and from 1181 "bilateral" keratoconus (KC) patients, along with 551 normal topography eyes from patients with very asymmetric ectasia (VAE-NT), and their 474 unoperated ectatic (VAE-E) eyes. The current TBIv1 (tomographic-biomechanical index) was tested, and an optimized AI algorithm was developed for augmenting accuracy. RESULTS: The area under the receiver operating characteristic curve (AUC) of the TBIv1 for discriminating clinical ectasia (KC and VAE-E) was 0.999 (98.5% sensitivity; 98.6% specificity [cutoff: 0.5]), and for VAE-NT, 0.899 (76% sensitivity; 89.1% specificity [cutoff: 0.29]). A novel random forest algorithm (TBIv2), developed with 18 features in 156 trees using 10-fold cross-validation, had a significantly higher AUC (0.945; DeLong, P < .0001) for detecting VAE-NT (84.4% sensitivity and 90.1% specificity; cutoff: 0.43; DeLong, P < .0001) and a similar AUC for clinical ectasia (0.999; DeLong, P = .818; 98.7% sensitivity; 99.2% specificity [cutoff: 0.8]). Considering all cases, the TBIv2 had a higher AUC (0.985) than TBIv1 (0.974; DeLong, P < .0001). CONCLUSIONS: AI optimization to integrate Scheimpflug-based corneal tomography and biomechanical assessments augments accuracy for ectasia detection, characterizing ectasia susceptibility in the diverse VAE-NT group. Some patients with VAE may have true unilateral ectasia. Machine learning considering additional data, including epithelial thickness or other parameters from multimodal refractive imaging, will continuously enhance accuracy. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Assessment of the corneal biomechanical features of granular corneal dystrophy type 2 using dynamic ultra-high-speed Scheimpflug imaging.

PURPOSE: To evaluate the corneal biomechanical features of eyes with granular corneal dystrophy type 2 (GCD2) by analyzing corneal biomechanical indices obtained using a Corvis ST (CST) dynamic ultra-high-speed Scheimpflug imaging device. METHODS: In this retrospective case-control study, 35 CST parameters were compared in normal eyes (control) and eyes of patients with GCD2 treated at Osaka University Hospital, Osaka, Japan. The parameters included the Corvis Biomechanical Index (CBI), which is important in differentiating eyes with keratoconus from normal eyes. We measured the deposition rates of lesions in the central 7-mm region of the eye and assessed the correlation between the deposition rate and the CBI. RESULTS: Twenty-one eyes with GCD2 and 23 control eyes were analyzed. Eyes with GCD2 showed significantly less corneal stiffness in 15 CST parameters than did control eyes. In particular, the CBI was remarkably higher in eyes with GCD2 than in control eyes (P = 0.000006). Additionally, the deposition rate and the CBI were positively correlated. CONCLUSIONS: GCD2 eyes had softer corneas than did control eyes in most biomechanical CST parameters, and one of the parameters (the CBI) was linked to the rate of deposited lesions. Since IOP may be underestimated in GCD2 eyes, management should be especially careful in GCD2 cases complicated by glaucoma.

Fourier Analysis on Irregular Corneal Astigmatism Using Optical Coherence Tomography in Various Severity Stages of Keratoconus.

PURPOSE: To investigate the diagnostic capability of Fourier indices in detecting clinical or subclinical keratoconus (KC). DESIGN: Prospective cross-sectional study. METHODS: The study included 126 eyes with clinical KC (50 KC without any corneal scar, 50 KC with anterior corneal scar, and 26 KC with posterior scar having a history of acute corneal hydrops), 50 with topographic KC (without clinical signs), 50 with pre-topographic KC (normal topography without clinical signs), and 50 controls. Corneal tomographic data were obtained using anterior segment optical coherence tomography (OCT). Fourier analysis decomposed dioptric data from both anterior and posterior corneal surface into spherical, regular astigmatism, asymmetry, and higher-order irregularity components. The discriminating ability of the Fourier indices of pre-topographic KC, topographic KC, and clinical KC from controls were assessed after quantitative Fourier analysis of irregular corneal astigmatism. RESULTS: Posterior asymmetry and higher-order irregularity components were significantly greater in pre-topographic KC eyes than those in controls (P < .001 for both), with the highest area under the receiver operating characteristic curve (AUROC) of 0.778 and 0.709, respectively. The same was true for anterior asymmetry, posterior asymmetry, and posterior higher-order irregularity components in topographic KC (AUROC of 0.945, 0.941, and 0.893, respectively), whereas it was >0.948 for all Fourier components in clinical KC. CONCLUSIONS: Fourier analysis using OCT can evaluate anterior and posterior corneal irregular astigmatism of various KC stages, from very mild to advanced, including severe cases with corneal scar. Irregular astigmatism indices from the posterior corneal surface showed the highest AUROC values in discriminating early KC stages.

Evaluation of ocular surface and tear function - A review of current approaches for dry eye.

An increasing prevalence of dry eye disease in the past decade has resulted in a greater focus on diagnostic methods for this condition. There has been a proliferation of technologies that attempt to quantify various aspects of tear function and ocular surface health. However, a cost-effective, simple, and efficient method remains elusive. In the Indian context, the majority of these patients present to the general ophthalmologist, and a clinical approach that is quick and easy to perform would allow widespread usage for accurate diagnosis. This article reviews currently available methods and their relevance to the general ophthalmologist.

Preliminary demonstration of a novel intraocular lens power calculation: the O formula.

PURPOSE: To evaluate the performance of a new formula of intraocular lens (IOL) power calculation (the O formula) based on ray tracing without commonly used parameters, including ultrasound-compatible axial length, keratometry readings, and A-constant. SETTING: Tokyo Medical Center, Tokyo, Japan. DESIGN: Retrospective consecutive case series. METHODS: 423 eyes (423 patients) implanted with a single-piece, L-loop, acrylic IOL were enrolled. All biometric data for the O formula were obtained by anterior segment swept-source optical coherence tomography (SS-OCT) and SS-OCT-based biometer. The performance of the O formula was compared with those of the Barrett Universal II (BUII) and Kane formulas at 1 month postoperatively. Statistical analysis was applied according to a heteroscedastic test with SD of prediction errors as the main parameter for formula performance. RESULTS: The SD of the O formula (0.426) was statistically significantly lower than that of the BUII formula (0.464, P = .034) but not statistically significantly different from that of the Kane formula (0.433, P = .601). The percentages of patients with refractive prediction errors within ±0.50 diopter (D) and ±1.00 D of the O, BUII, and Kane formulas were 75.4% and 98.6%, 77.1% and 97.9%, and 76.6% and 98.1%, respectively. CONCLUSIONS: The O formula, based on ray tracing using SS-OCT-based devices, is one of the promising approaches for IOL power calculation, although additional larger scale studies are needed. It may be used as an alternative in IOL power calculation because of its independence from commonly used parameters.

Novel corneal morphological alterations in Vogt-Koyanagi-Harada disease.

PURPOSE: To determine whether visual function, especially when dependent on the anterior segment of ocular tissue, is altered during high-dose steroid treatment for Vogt-Koyanagi-Harada disease (VKH). STUDY DESIGN: Retrospective case series METHODS: This case series included 18 eyes of 18 patients with VKH who received high-dose steroid therapy as initial treatment. All patients underwent anterior swept-source optical coherent tomography (CASIA-2) examinations during their clinical course to measure the central corneal thickness (CCT), average central corneal power (ACCP), maximum curvature (Kmax) and anterior chamber depth (ACD). RESULTS: The treatment duration was classified into the initial phase (earliest initial phase eIP; 0-1 month, initial phase: IP; 1-3months), middle phase (MP; 3-6 months), and late phase (LP; 6-9 months). The CCT decreased significantly after treatment (eIP vs. IP, p<0.01, eIP vs. MP, p<0.01; eIP vs. LP, p<0.01). The CCT at eIP was correlated with the flare value at 0M (R2=0.22). The change in Kmax at MP and LP was correlated with the flare value at 0M. Moreover, CCT at MP was correlated with rate of change in nasal angle open distance (AOD) at IP and rate of change in temporal AOD at IP. CONCLUSIONS: This study was the first to reveal morphological changes in the anterior segment of the eye in VKH using CASIA-2, which may affect visual acuity and the astigmatic axis. It is vital to assess corneal morphology to determine the cause of visual function deterioration in patients with VKH.

Exploratory Search for Characteristic Symptoms to Distinguish Meibomian Gland Dysfunction from Dry Eye in a Population-Based Study in Japan.

Symptom overlap between meibomian gland dysfunction (MGD) and dry eye (DE) makes it difficult to distinguish between these two conditions on the basis of symptoms alone. We searched for characteristic symptoms that might help to distinguish MGD from DE on the basis of a population-based study. Subjects comprised 311 residents of Takushima island (18 to 96 years), including 117 individuals with MGD and 114 with DE. Responses to a symptom-related questionnaire (19 items) were subjected to factor analysis, and univariate regression analysis was performed to identify ocular surface parameters associated with characteristic symptoms of MGD. Factor analysis revealed aggregation of symptoms according to three factors: Factor 1 related to Symptom Score, Factor 2 to DE, and Factor 3 to MGD. Symptoms associated with DE included 11 items, whereas the only item related to MGD was tearing sensation. Pearson's correlation analysis revealed that tearing sensation was associated with tear meniscus height (TMH), noninvasive tear-film breakup time, fluorescein staining score, meiboscore, meibum grade, and Schirmer value. Subjects with MGD experienced significantly more tearing and had a larger TMH than did those without MGD (p = 0.0334). Tearing sensation may thus be a characteristic symptom of MGD. Physicians should suspect MGD who complain of tearing sensation.