[Difference and distance between the central and thinnest points of the cornea: impact of refractive state, age and ocular side]

BACKGROUND

The aim of the study was to quantify the difference in corneal thickness between the central and thinnest points (∆PachyZ-PachyD), the distance between the center of the cornea and its thinnest point (vector length PachyD) and to explore the impact of refractive state, age and ocular side.

PATIENTS AND METHODS

This was a multicenter, retrospective, cross-sectional study and medical records of 16,872 eyes were reviewed. The Orbscan® (Bausch and Lomb) procedure was used for pachymetry and keratometry.

RESULTS

The results showed that ∆PachyZ-PachyD and vector length PachyD were higher in hyperopic eyes (∆PachyZ-PachyD: 11.99 ± 12.08 µm, vector length PachyD: 0.85 ± 0.44 mm) compared to myopic eyes (∆PachyZ-PachyD: 9.2 ± 7.86 µm, vector length PachyD: 0.7 ± 0.37 mm; p < 0.001). Refractive state, age and ocular side demonstrated an independent, statistically significant impact on ∆PachyZ-PachyD and vector length PachyD.

CONCLUSIONS

As a result of the significant impact of refractive state, age and ocular side on ∆PachyZ-PachyD and vector length PachyD, these variables should be considered in a normative data collection.

Eye laterality: a comprehensive analysis in refractive surgery candidates

PURPOSE

To explore eye laterality (higher refractive error in one eye) and its association with refractive state, spherical/astigmatic anisometropia, age and sex in refractive surgery candidates.

METHODS

Medical records of 12 493 consecutive refractive surgery candidates were filtered. Refractive error (subjective and cycloplegic) was measured in each subject and correlated with eye laterality. Only subjects with corrected distance visual acuity (CDVA) of >20/22 in each eye were enrolled to exclude amblyopia. Associations between eye laterality and refractive state were analysed by means of t-test, chi-squared test, Spearman's correlation and multivariate logistic regression analysis, respectively.

RESULTS

There was no statistically significant difference in spherical equivalent between right (-3.47 ± 2.76 D) and left eyes (-3.47 ± 2.76 D, p = 0.510; Pearson's r = 0.948, p < 0.001). Subgroup analysis revealed (I) right eye laterality for anisometropia >2.5 D in myopic (-5.64 ± 2.5 D versus -4.92 ± 2.6 D; p = 0.001) and in hyperopic (4.44 ± 1.69 D versus 3.04 ± 1.79 D; p = 0.025) subjects, (II) a tendency for left eye cylindrical laterality in myopic subjects, and (III) myopic male subjects had a higher prevalence of left eye laterality. (IV) Age did not show any significant impact on laterality.

CONCLUSIONS

Over the full refractive spectrum, this study confirmed previously described strong interocular refractive correlation but revealed a statistically significant higher rate of right eye laterality for anisometropia >2.5 D. In general, our results support the use of data from one eye only in studies of ocular refraction.

[Therapeutic excimer laser treatment of the cornea]

Concomitant with new innovations in the field of refractive surgery, therapeutic excimer laser applications like phototherapeutic keratectomy (PTK) and topography-guided customised ablation treatment are gaining high importance and undergoing rapid evolution. Nowadays, PTK is an effective treatment modality for superficial corneal pathologies. Primary indications are decreased epithelial adherence, superficial opacifications and an irregular corneal surface. For the right indication and successful treatment of corneal pathologies with PTK, a knowledge of the size, depth and nature of the pathology, as well as the refractive status of both eyes is important. Next to slit-lamp examination, objective measuring systems like the topography, confocal microscopy and the anterior segment OCT facilitate presurgical planning. Regarding the treatment procedure the surgeon can choose between a variety of methods. PTK can be combined with manual epithelial debridement or done by only using the excimer laser. In the case of an irregular corneal surface, depending on the pathology, masking fluids or topography-guided custom ablation protocols can increase the visual outcome. To avoid recurrence of the underlying pathology (e.g., corneal dystrophy, haze), the topical application of 0.02% mitomycin C for 20-60 seconds has proved to be a safe and effective procedure. If the surgeon considers all the patient-related factors carefully and manages to combine the available treatment options correctly, PTK embodies an effective and minimally invasive alternative to lamellar or penetrating keratoplasty.

Subjective pain, visual recovery and visual quality after LASIK, EpiLASIK (flap off) and APRK - a consecutive, non-randomized study

INTRODUCTION

Laser in situ keratomileusis (LASIK) is superior to surface ablation techniques (SAT) such as alcohol photorefractive keratectomy (APRK) or Epi-LASIK (EpiK) in terms of visual recovery and postoperative pain. This study compares subjective symptoms and visual recovery of two different SATs with LASIK.

MATERIALS AND METHODS

One hundred and twenty seven patients were operated using one of the three techniques. Patients filled out a questionnaire describing symptoms assessing subjective visual recovery on a linear scale from 'not functioning' to 'full visual function' and pain on a linear scale from 'no pain' to 'severe daily pain'. Subjective symptoms such as halos, double vision, low night vision, reduced contrast and dry eyes were also evaluated.

RESULTS

Visual recovery was faster and discomfort symptoms less pronounced with the LASIK than with surface ablation procedures. More pain was reported after APRK than after EpiK (flap-off technique) in the early postoperative period, with a maximum of pain on postoperative days 3-4. Subjective visual recovery showed no statistically significant difference between the two surface ablation procedures. Halos, double vision, low night vision, reduced contrast and dry eyes were more extensively reported by the EpiK than the APRK group and were less pronounced in the LASIK than in the SAT group.

DISCUSSION AND CONCLUSIONS

Our study does not uniformly support the previously published favourable results of EpiK compared to APRK with regard to subjective recovery of vision and postoperative pain.

Association between ocular dominance and spherical/astigmatic anisometropia, age, and sex: analysis of 1274 hyperopic individuals

PURPOSE

To determine the association between ocular dominance and spherical/astigmatic anisometropia, age, and sex in hyperopic subjects.

METHODS

The medical records of 1274 hyperopic refractive surgery candidates were filtered. Ocular dominance was assessed with the hole-in-the-card test. Refractive error (manifest and cycloplegic) was measured in each subject and correlated to ocular dominance. Only subjects with corrected distance visual acuity of >20/22 in each eye were enrolled, to exclude amblyopia. Associations between ocular dominance and refractive state were analyzed by means of t-test, χ(2) test, Spearman correlation, and multivariate logistic regression analysis.

RESULTS

Right and left eye ocular dominance was noted in 57.4 and 40.5% of the individuals. Nondominant eyes were more hyperopic (2.6 ± 1.27 diopters [D] vs. 2.35 ± 1.16 D; P < 0.001) and more astigmatic (-1.3 ± 1.3 D vs. -1.2 ± 1.2 D; P = 0.003) compared to dominant eyes. For spherical equivalent (SE) anisometropia of >2.5 D (n = 21), the nondominant eye was more hyperopic in 95.2% (SE 4.7 ± 1.4 D) compared to 4.8% (1.8 ± 0.94 D; P < 0.001) for the dominant eye being more hyperopic. For astigmatic anisometropia of >2.5 D (n = 27), the nondominant eye was more astigmatic in 89% (mean astigmatism -3.8 ± 1.1 D) compared to 11.1% (-1.4 ± 1.4 D; P < 0.001) for the dominant eye being more astigmatic.

CONCLUSIONS

The present study is the first to show that the nondominant eye has a greater degree of hyperopia and astigmatism than the dominant eye in hyperopic subjects. The prevalence of the nondominant eye being more hyperopic and more astigmatic increases with increasing anisometropia.

Association between ocular dominance and spherical/astigmatic anisometropia, age, and sex: analysis of 10,264 myopic individuals

PURPOSE

To determine the association between ocular dominance and spherical or astigmatic anisometropia, age, and sex.

METHODS

Medical records of 10,264 myopic refractive surgery candidates were filtered. Ocular dominance was assessed with the hole-in-the-card test. Manifest refractive error was measured in each subject and correlated to ocular dominance. Only subjects with corrected distance visual acuity (CDVA) of >20/22 in each eye were enrolled, to exclude amblyopia. Associations between ocular dominance and refractive state were analyzed by means of the t-test, χ(2) test, Spearman correlation, and multivariate logistic regression analysis.

RESULTS

Right and left eye ocular dominance was noted in 61.7% and 35.6% of the individuals. Ocular dominance had no significant impact on SE refraction in subjects with SE or cylindrical anisometropia <0.5 D. For anisometropia >2.5 D (n = 278) the nondominant eye was more myopic in 63.7% (SE -5.8 ± 2.64 D) compared to 36.3% (-4.69 ± 2.39 D; P < 0.001; adjusted P (Padj) < 0.001) for the dominant eye being more myopic. Nondominant eyes showed higher astigmatic power than dominant eyes (-0.95 ± 0.91 D versus -0.89 ± 0.84 D; P < 0.001). For astigmatic anisometropia >2.5 D, nondominant eyes exhibited a higher amount of astigmatism in 75% of subjects. Nondominant eyes of subjects <29 years and 30 to 39 years of age had a significantly higher astigmatic power than did dominant eyes of the same age group.

CONCLUSIONS

In contrast to previous reports, this study, including myopic refractive surgery candidates, revealed that the nondominant eye was more myopic for SE anisometropia >2.5 and more astigmatic for cylindrical anisometropia >0.5 D.

Relationship between minimum corneal thickness and refractive state, keratometry, age, sex, and left or right eye in refractive surgery candidates

PURPOSE

To evaluate the relationship between the thinnest point in corneal thickness and the refractive state, keratometry, age, sex, and the ocular side.

SETTING

Eye clinics in Germany and Austria and the Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

DESIGN

Cross-sectional study.

METHODS

Medical records of refractive surgery candidates from 2006 to 2010 were reviewed. Univariate variance analysis, covariance analysis, Bravis-Pearson correlations, Spearman rank correlations, and t tests were performed to analyze the relationship between the thinnest point in corneal thickness and the biometric parameters.

RESULTS

The study evaluated 4600 eyes. The mean thinnest point in corneal thickness was 549 μm ± 33 (SD). Refractive state, mean keratometry, and age had a statistically significant impact on the thinnest point in corneal thickness. The mean thinnest point in corneal thickness was 548 ± 33 μm in myopia, 555 ± 34 μm in hyperopia, and 553 ± 35 μm in high astigmatism, with a statistically significant difference between hyperopic eyes and myopic eyes (P<.001). No correlation was found between the thinnest point in corneal thickness and sex or ocular side. Refractive state (r = 0.07, P<.001) and age (r = 0.05, P<.001) showed a positive correlation and keratometry (r = -0.09, P<.001) a negative correlation with the thinnest point in corneal thickness.

CONCLUSIONS

Refractive state, mean keratometry, and age had a statistically significant, although marginal impact, on the thinnest point in corneal thickness. Sex and the ocular side had no effect.

Bilateral crystalline corneal deposits as first clinical manifestation of monoclonal gammopathy: a case report

Aims

To report the clinical and diagnostic findings of a patient with bilateral corneal deposits caused by an underlying monoclonal gammopathy.

Methods

Slit-lamp biomicroscopy, confocal microscopy and additional serological tests were performed on a 35-year-old man presenting with bilateral crystalline corneal deposits.

Results

The patient was diagnosed as having monoclonal gammopathy based on elevated levels of serum immunoglobulin G. Confocal microscopy showed highly reflective (protein) deposits throughout the entire cornea, with the highest density in the epithelium and anterior stromal keratocytes.

Conclusions

Monoclonal gammopathy, a potential sign of a life-threatening disease, can lead to dense, bilateral corneal deposits. As such changes can occur long before ocular or systemic discomforts appear, an early diagnosis is crucial. Ophthalmologists should be aware of corneal deposits as potential warning signs of monoclonal gammopathy.

[Infectious keratitis after LASIK--update and survey of the literature]

LASIK has become the preferred surgical procedure for the correction of refractive errors. Microbial keratitis is a rare but severe complication. The incidence of post-LASIK keratitis, (uni- and bilateral) is difficult to estimate. The risk of bilateral infection could until now only be approximated by calculating it from the risk of unilateral infection. Due to the fortunately low incidence of post-LASIK keratitis, large-scale studies are necessary to obtain valid statistical data. The American Society of Cataract and Refractive surgery (ASCRS) developed a post-LASIK infectious keratitis survey in 2001. 116 post-LASIK infections were reported by the members of the society. The calculated incidence was 0.035 % or 1 infection in every 2919 procedures. Llovet et al. found 9 patients (18 eyes) with bilateral post-LASIK keratitis out of 204 586 procedures (incidence 0.0084 %). Gram-positive bacteria and atypical mycobacteria are the most common causes for microbial post-LASIK keratitis. There is an increasing literature of post-LASIK case reports caused by rare or atypical species. Severe cases of keratitis are more often correlated with a prolonged onset of infection and caused by atypical species. An overview of the current literature and our own data regarding post-LASIK keratitis (uni-, and bilateral) are presented.

Bilateral Achromobacter xylosoxidans keratitis after laser in situ keratomileusis

A 31-year-old man was referred to us 2 months after bilateral laser in situ keratomileusis (LASIK). On presentation, the corrected distance visual acuity was hand motion in the right eye and 20/25 in the left eye. Slitlamp examination showed a diffuse central stromal infiltrate, flap melting, and hypopyon in the right eye and marked interface opacities with crystal-like edges in the left eye. Flap lift and irrigation were performed. Because of the progressive keratitis, penetrating keratoplasty (PKP) was done in both eyes. Achromobacter xylosoxidans was isolated from both corneal buttons, and therapy was changed to chloramphenicol prednisolone eyedrops 8 times a day and intravenous meropenem 500 mg 3 times a day according to sensitivity testing. Two months after surgery, both transplants remained clear.

A phase II study evaluating the efficacy and safety of single agent IMC A12, a monoclonal antibody (MAb), against the insulin-like growth factor-1 receptor (IGF-IR), as monotherapy in patients with metastastic, asymptomatic castration-resistant prostate cancer (CRPC)

5142

Background: IGF-IR-mediated signaling contributes to prostate cancer carcinogenesis and pathogenesis and may be associated with hormone resistance. IMC-A12 is a fully human IgG1 MAb that specifically targets the IGF-IR and inhibits ligand binding and signaling. In xenografts, IMC-A12 inhibits growth of both androgen-dependent and -independent prostate cancer. This phase 2, multicenter study was designed to assess the safety and antitumor activity of IMC-A12 in asymptomatic pts with metastatic CRPC who were chemotherapy-naive. Methods: Pts received IMC-A12 10 mg/kg IV every 2 wks; until evidence of progressive disease (PD), intolerable toxicity, or other withdrawal criteria were met. Radiologic evaluation was performed every 8 wks. PD by bone scan required at least 2 new lesions with confirmation at subsequent imaging per PCWG2. Results: 19 of 31 pts treated have discontinued IMC-A12, 12 due to PD. 9 of 31 pts experienced disease stabilization for ≥6 mos (range: 7.4–12.5 mos), 5 pts (3 with PSA reduction) continue on IMC-A12. The most common AEs possibly or probably related to IMC-A12, were fatigue (25.8%) and hyperglycemia (19.4%). In 4 pts cases of Grade 3 hyperglycemia was treatment related none requiring discontinuation of IMC-A12; 1 pt required insulin but continued on study. Approximately 70% of pts experienced at least transient elevation of nonfasting glucose to above normal range. Other AEs grade ≥3 at least possibly related to IMC-A12 were one case each of thrombocytopenia (requiring IMC-A12 discontinuation), hyperkalemia, fatigue, pneumonia (resulting in death), and Grade 4 pharmacokinetic and pharmacodynamic analayses are pending leukoencephalopathy (probably related; requiring IMC-A12 discontinuation). Pharmakinetic and pharmacodynamic analyses are pending. Conclusions: IMC-A12 monotherapy appears well tolerated in pts with metastatic asymptomatic CRPC. As in phase I, hyperglycemia was largely asymptomatic and manageable. Disease stabilization for > 6 months in 9 of 31 pts suggests that IMC- A12 may have modest antitumor activity. Additional studies of IMC-A12 in CRPC are planned.

[Table: see text]