To analyze the refractive and keratometric stability in hyperopic astigmatic laser in situ kerato... more To analyze the refractive and keratometric stability in hyperopic astigmatic laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) during the first 6 months after surgery. This retrospective cross-sectional study included 97 hyperopic eyes; 55 were treated with LASIK and 42 with PRK. Excimer ablation for all eyes was performed using the ALLEGRETTO excimer laser platform using a mitomycin C for PRK and a mechanical microkeratome for LASIK. Keratometric and refractive data were analyzed during three consecutive follow-up intervals (6 weeks, 3 months, and 6 months). The corneal topography was obtained using Scheimpflug topography, and subjective refractions were acquired by expert optometrists according to a standardized protocol. After 3 months, mean keratometry and spherical equivalent were stable after LASIK, whereas PRK-treated eyes presented statistically significant (P<0.001) regression of hyperopia. In eleven cases, hyperopic regression of >1 D occurred. The optical zone diameter did not correlate with the development of regression. After corneal laser refractive surgery, keratometric changes are followed by refractive changes and they occur up to 6 months after LASIK and for at least 6 months after PRK, and therefore, caution should be applied when retreatment is planned during the 1st year after surgery because hyperopic refractive regression can lead to suboptimal visual outcome. Keratometric and refractive stability is earlier achieved after LASIK, and therefore, retreatment may be independent of late regression.
Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie, Jan 3, 2016
Previous studies have suggested that, to improve refractive predictability in hyperopic LASIK tre... more Previous studies have suggested that, to improve refractive predictability in hyperopic LASIK treatments, preoperative cycloplegic or manifest refraction, or a combination of both, could be used in the laser nomogram. We set out to investigate (1) the prevalence of a high difference between manifest and cycloplegic spherical equivalent in hyperopic eyes preoperatively, and (2) the related predictability of postoperative keratometry. Retrospective cross-sectional data analysis of consecutive treated 186 eyes from 186 consecutive hyperopic patients (mean age 42 [±12] years) were analyzed. Excimer ablation for all eyes was performed using a mechanical microkeratome (SBK, Moria, France) and an Allegretto excimer laser platform. Two groups were defined according to the difference between manifest and cycloplegic spherical equivalent which was defined as ≥1.00 diopter (D); the data was analyzed according to refractive outcome in terms of refractive predictability, efficacy, and safety. In...
To investigate the influence of lag time between the onset of central visual acuity loss and surg... more To investigate the influence of lag time between the onset of central visual acuity loss and surgical intervention of macula-off retinal detachment. This retrospective case series examined all consecutively treated eyes with primary macula-off retinal detachment at the University Hospital Hamburg (Germany) from February 2010 to February 2015. Records of 1727 patients operated by six surgeons were reviewed. Eighty-nine eyes (5.2%) from 89 patients met the inclusion and exclusion criteria. The main outcome measure studied was final visual acuity as a function of symptom duration of macula-off detachment. Secondary outcome measures studied were influence of age and surgical technique. Symptom duration was defined as the time from the onset of loss of central vision to surgical intervention. After 10 days no clinically relevant difference was seen in final visual acuity. Eyes with symptom duration of 3 days or less achieved best final visual acuity (p<0.001). Age and preoperative visual acuity had no influence while vitrectomised eyes had better outcome compared with those with scleral buckling. Our study suggests that 1. After 10 days of central visual acuity loss, the final visual outcome is clinically comparable and independent of further delay of surgery up to 30 days. 2. Eyes treated up to 3 days after onset of loss of central vision have better final visual acuity than eyes with longer lag time. However, we did not find statistically significant differences within the first 3 days. 3. Surgery for macula-off retinal detachment may therefore most likely not be postponed without compromising the patient's visual prognosis.
The British journal of ophthalmology, Jan 18, 2016
To explore the application of intraoperative wavefront aberrometry (IWA) for aphakia-based biomet... more To explore the application of intraoperative wavefront aberrometry (IWA) for aphakia-based biometry using three existing formulae derived from autorefractive retinoscopy and introducing new improved formulae. In 74 patients undergoing cataract surgery, three repeated measurements of aphakic spherical equivalent (SE) were taken. All measurements were objectively graded for their quality and evaluated with the 'limits of agreement' approach. ORs were calculated and analysis of variance was applied. The intraocular lens (IOL) power that would have given the target refraction was back-calculated from manifest refraction at 3 months postoperatively. Regression analysis was performed to generate two aphakic SE-based formulae for predicting this IOL. The accuracy of the formulae was determined by comparing them to conventional biometry and published aphakia formulae. In 32 eyes, three consecutive aphakic measurements were successful. Objective parameters of IWA map quality signific...
To evaluate the effect of corneal cross-linking (CXL) in progressive keratoconus by applying in v... more To evaluate the effect of corneal cross-linking (CXL) in progressive keratoconus by applying in vivo static and dynamic Scheimpflug analyses. In this longitudinal retrospective study, corneal topography and tomography (Pentacam HD) and dynamic Scheimpflug-based biomechanical analyses (CorvisST [CST]) of 24 eyes of 24 patients with progressive keratoconus before and 6 months after CXL were reviewed. New dynamic curve analyses, provided by Oculus Optikgeräte, were performed to analyze corneal dynamics throughout the entire response to the CST air puff impulse. Besides subtle changes of topography and tomography, only the CorvisST predefined parameters peak distance (-0.5 mm) and radius of the intended cornea (+0.5 mm; P < .05) demonstrated statistically significant differences 6 months after CXL. Using new dynamic curve analyses, additional distinct changes of the corneal biomechanical characteristics after CXL were noted. Published results of corneal biomechanical changes after CXL for progressive keratoconus based on single, predefined CST parameters are inconsistent. The new dynamic curve analyses demonstrate distinct changes of the biomechanical properties of the cornea and might therefore be the next step in understanding in vivo analyses of corneal biomechanics. [J Refract Surg. 2016;32(1):34-39.].
To improve keratoconus (KC) screening with new in vivo biomechanical Scheimpflug analyses. After ... more To improve keratoconus (KC) screening with new in vivo biomechanical Scheimpflug analyses. After adjusting for intraocular pressure and corneal thickness, predefined static and new dynamic Scheimpflug curve analyses [Pentacam HR and Corvis ST (CST); Oculus] of 87 normal eyes, 27 subclinical KC eyes, 42 suspected KC, and 65 manifest KC eyes were reviewed retrospectively. A t test (for a normal distribution), Wilcoxon matched-pairs test (if not normally distributed), and receiver operating characteristics were used to test for statistically significant differences between these groups. In addition, new dynamic curve analyses were performed to analyze corneal dynamics throughout the entire response to the CST air puff impulse. Comparing normal and KC-suspect eyes, the parameters A1 length, A2 length, radius of the inward-bended cornea, and deflection length at the highest concavity revealed statistically significant differences. In addition, the newly calculated "applanation length level" and "deflection length level" demonstrated consistently increasing differences with increasing statistical significance between normal eyes and those with advancing KC stages. However, when comparing normal and subclinical KC eyes, none of the analyzed parameters demonstrated statistically significant differences. In vivo biomechanical analyses (CST) at their current state only marginally improve KC screening protocols. Newly generated parameters such as the applanation length level and deflection length level might further improve early KC screening.
Es gibt allgemein bekannte Fallstricke bei der Wahl der geeigneten Behandlungsstrategie in der ho... more Es gibt allgemein bekannte Fallstricke bei der Wahl der geeigneten Behandlungsstrategie in der hornhautrefraktiven Chirurgie. Einer von ihnen ist der Konflikt zwischen den Modellen, die entweder nur auf dem topographischen oder subjektiven präoperativen Zylinder basieren.
To compare the effect of a rotating microkeratome (M2) and a linear microkeratome (SBK) on the ch... more To compare the effect of a rotating microkeratome (M2) and a linear microkeratome (SBK) on the change in the astigmatic component in eyes with preoperative plano refractive cylinder. University Medical Centre Hamburg-Eppendorf, Hamburg, Germany. Retrospective case series. An Allegretto excimer laser was used to perform laser ablation in myopic eyes of consecutive patients. The laser in situ keratomileusis (LASIK) procedure included mechanical flap preparation using a microkeratome, either a linear type with a single-use 90 μm head to create a nasal hinge or a rotating type with a single-use 90 μm head to create a superior hinge. The Alpins vector method was applied to describe the effects of LASIK on postoperative refractive cylinder. The study evaluated 1045 eyes of 852 patients. Although the mean overall efficacy and safety indices indicate the procedure was highly precise, safe, and efficient, there were statistically significant differences in surgically induced astigmatism (SIA) between the microkeratomes (P = .002). The postoperative refractive cylinder (ie, SIA) was 0.75 diopter (D) or more in 116 eyes (11.1%), 44 (12.8%) of 344 linear cases and 72 (10.3%) of 701 rotating cases. Independent of the type of microkeratome used, the SIA was slightly higher in eyes treated first; the mean magnitude of the induced astigmatism was 0.35 D. In approximately 10% of eyes with preoperative plano refractive myopia, the astigmatic component tended to be overcorrected. Nevertheless, independent of the type of microkeratome, the maximum mean magnitude of refractive cylinder documented was 0.35 D. No author has a financial or proprietary interest in any material or method mentioned.
In eyes with a preoperative plano refractive cylinder, it would appear that there is no rationale... more In eyes with a preoperative plano refractive cylinder, it would appear that there is no rationale for astigmatic treatment. The aim of this retrospective, cross-sectional data analysis was to determine the amount of topographic astigmatism in refractive plano eyes that results in reduced efficacy after myopic laser in situ keratomileusis (LASIK). This study included 267 eyes from 267 consecutive myopic patients with a refractive plano cylinder. Receiver operating characteristic analysis was used to find the cut-off values of preoperative ocular residual astigmatism (= topographic astigmatism) that can best discriminate between groups of efficacy and safety indices in preoperative plano refractive cylinder eyes. Preoperative ocular residual astigmatism (ORA) (or topographic astigmatism) of ≤0.9 diopters (D) resulted in an efficacy index of at least 0.8 statistically significantly more frequently than eyes with a preoperative ORA of >0.9 D. Eyes with a high ORA preoperatively also ...
PURPOSE: We aimed to determine the incidence of buttonhole after laser in situ keratomileusis (LA... more PURPOSE: We aimed to determine the incidence of buttonhole after laser in situ keratomileusis (LASIK). We also evaluated possible risk factors, treatment strategies and visual outcome. SETTING: multicentric, including several international clinics. METHODS: : In this comparative case series we reviewed the medical records of 164,603 patients (315,259 eyes) that underwent LASIK from January 2003 to December 2011 to identify cases of buttonhole. All surgeries were performed by means of a manual microkeratome. The main outcome measures were incidence of buttonhole after LASIK, response to treatment and visual outcome. Possible risk factors, clinical course, days to retreatment and surgical treatment were recorded. RESULTS: Buttonhole was found in 137 eyes in 134 patients (105 myopes and 32 hyperopes). Age, preoperative refraction and keratometric power were not statistically significant independent risk factors. Buttonholes appeared in thinner corneas. Patients were retreated with a ne...
To analyse tomographic changes in eyes classified as &amp... more To analyse tomographic changes in eyes classified as 'normal', 'keratoconus-suspect' and 'clinically manifest keratoconus' based on the established KISA% definition of Rabinowitz and Rasheed and to develop the category of 'subclinical keratoconus eyes' to expand the classification into a 'subtopographic' range. Tomographic and topographic analyses of 670 eyes performed with a rotating Scheimpflug imaging system (Pentacam(®) , Oculus Inc., Wetzlar, Germany) were retrospectively analysed. Based on the KISA% keratoconus classification system, eyes were assigned to a 'normal', 'keratoconus-suspect' or 'manifest keratoconus' group. In addition, a new group of 'subclinical keratoconus eyes' was analysed, comprising unsuspicious fellow eyes of patients with keratoconus. T-tests, Wilcoxon rank-sum test, receiver operating characteristics (ROC) and robust regression analyses were performed to correlate tomographic parameters with the increasing KISA% index. KISA%-grouped keratoconus eyes showed robust tomographic changes. By adding the subclinical group, although the concurrent topography was unchanged, we were able to demonstrate statistically significant changes for almost all tomographic parameters (parameters with highest sensitivity/specificity: ART_max, [0.69/0.69], BAD_D [0.66/0.66]). The highest coefficient of determination (R(2) ) with the KISA% index was demonstrated for Ele_f_max (R(2) = 0.70), Ele_f_TP (R(2) = 0.69), Ele_b_TP (R(2) = 0.69) and BAD_D (R(2) = 0.68). We recommend the use of the expanded KISA% index (eKISA% index) as the basis for the definition of keratoconus and normal groups in future keratoconus research projects.
To examine the impact of temperature and sunlight duration on refractive and visual outcome of la... more To examine the impact of temperature and sunlight duration on refractive and visual outcome of laser-assisted in situ keratomileusis (LASIK) in myopic eyes. University Medical Center Hamburg-Eppendorf, Germany, and Care Vision Refractive Centers, Germany. Retrospective, cross-sectional data analysis. This study comprised 1,052 eyes of 1,052 consecutive myopic patients (419 males, 633 females; mean age at surgery 35.0±9.0 years) with a mean preoperative refractive spherical equivalent (SE) of -3.88±1.85 diopters (D). Two subgroups were defined, comprising patients undergoing surgery during either meteorological winter or summer. Manifest refraction, uncorrected, and corrected distant visual acuity (UDVA and CDVA) were assessed pre- and postoperatively. We applied robust regression analysis with efficiency index (EI), safety index (SI), and postoperative SE (in D) as dependent variables. At the 1-month (33.0±5.0 days) follow-up, the mean postoperative SE was -0.18±0.44 D. Bivariate co...
To examine the impact of seasonality on the refractive and visual outcomes of laser in situ kerat... more To examine the impact of seasonality on the refractive and visual outcomes of laser in situ keratomileusis (LASIK) in myopic eyes. Department of Ophthalmology and Care Vision Refractive Centers, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. Retrospective cross-sectional data analysis. Two subgroups were defined. The first comprised patients having surgery during meteorological winter and the second, patients having surgery during meteorological summer. The manifest refraction and uncorrected and corrected visual acuities were assessed preoperatively and postoperatively. Robust regression analysis was applied with the efficacy index, safety index, and postoperative SE as dependent variables. This study comprised 1052 eyes of 1052 consecutive myopic patients (419 men, 633 women; mean age at surgery 35.0 years ± 9.0 [SD]) with a mean preoperative refractive spherical equivalent (SE) of -3.88 ± 1.85 diopters (D). At the 1-month follow-up (mean 33.0 ± 5.0 days), the mean...
To provide the first clinical data in determining the feasibility, quality and precision of intra... more To provide the first clinical data in determining the feasibility, quality and precision of intraoperative wavefront aberrometry (IWA)-based refraction in patients with cataract. IWA refraction was recorded at 7 defined measurement points during standardised cataract surgery in 74 eyes of 74 consecutive patients (mean age 69±11.3 years). Precision and measurement quality was evaluated by the 'limits of agreement' approach, regression analysis, correlation analysis, Analysis of variance (ANOVA) and ORs for predicting measurement failure. Wavefront map (WFM) quality was objectivised and compared with the Pentacam Nuclear Staging analysis. Out of 814 IWA measurement attempts, 462 WFMs could be obtained. The most successful readings (n=63) were achieved in aphakia with viscoelastic. The highest (50.63%, SD 20.23) and lowest (29.19%, SD 13.94) quality of WFMs across all measurement points were found after clear corneal incision and in pseudophakia with viscoelastic, respectively....
To analyze the refractive and keratometric stability in hyperopic astigmatic laser in situ kerato... more To analyze the refractive and keratometric stability in hyperopic astigmatic laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) during the first 6 months after surgery. This retrospective cross-sectional study included 97 hyperopic eyes; 55 were treated with LASIK and 42 with PRK. Excimer ablation for all eyes was performed using the ALLEGRETTO excimer laser platform using a mitomycin C for PRK and a mechanical microkeratome for LASIK. Keratometric and refractive data were analyzed during three consecutive follow-up intervals (6 weeks, 3 months, and 6 months). The corneal topography was obtained using Scheimpflug topography, and subjective refractions were acquired by expert optometrists according to a standardized protocol. After 3 months, mean keratometry and spherical equivalent were stable after LASIK, whereas PRK-treated eyes presented statistically significant (P<0.001) regression of hyperopia. In eleven cases, hyperopic regression of >1 D occurred. The optical zone diameter did not correlate with the development of regression. After corneal laser refractive surgery, keratometric changes are followed by refractive changes and they occur up to 6 months after LASIK and for at least 6 months after PRK, and therefore, caution should be applied when retreatment is planned during the 1st year after surgery because hyperopic refractive regression can lead to suboptimal visual outcome. Keratometric and refractive stability is earlier achieved after LASIK, and therefore, retreatment may be independent of late regression.
Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie, Jan 3, 2016
Previous studies have suggested that, to improve refractive predictability in hyperopic LASIK tre... more Previous studies have suggested that, to improve refractive predictability in hyperopic LASIK treatments, preoperative cycloplegic or manifest refraction, or a combination of both, could be used in the laser nomogram. We set out to investigate (1) the prevalence of a high difference between manifest and cycloplegic spherical equivalent in hyperopic eyes preoperatively, and (2) the related predictability of postoperative keratometry. Retrospective cross-sectional data analysis of consecutive treated 186 eyes from 186 consecutive hyperopic patients (mean age 42 [±12] years) were analyzed. Excimer ablation for all eyes was performed using a mechanical microkeratome (SBK, Moria, France) and an Allegretto excimer laser platform. Two groups were defined according to the difference between manifest and cycloplegic spherical equivalent which was defined as ≥1.00 diopter (D); the data was analyzed according to refractive outcome in terms of refractive predictability, efficacy, and safety. In...
To investigate the influence of lag time between the onset of central visual acuity loss and surg... more To investigate the influence of lag time between the onset of central visual acuity loss and surgical intervention of macula-off retinal detachment. This retrospective case series examined all consecutively treated eyes with primary macula-off retinal detachment at the University Hospital Hamburg (Germany) from February 2010 to February 2015. Records of 1727 patients operated by six surgeons were reviewed. Eighty-nine eyes (5.2%) from 89 patients met the inclusion and exclusion criteria. The main outcome measure studied was final visual acuity as a function of symptom duration of macula-off detachment. Secondary outcome measures studied were influence of age and surgical technique. Symptom duration was defined as the time from the onset of loss of central vision to surgical intervention. After 10 days no clinically relevant difference was seen in final visual acuity. Eyes with symptom duration of 3 days or less achieved best final visual acuity (p<0.001). Age and preoperative visual acuity had no influence while vitrectomised eyes had better outcome compared with those with scleral buckling. Our study suggests that 1. After 10 days of central visual acuity loss, the final visual outcome is clinically comparable and independent of further delay of surgery up to 30 days. 2. Eyes treated up to 3 days after onset of loss of central vision have better final visual acuity than eyes with longer lag time. However, we did not find statistically significant differences within the first 3 days. 3. Surgery for macula-off retinal detachment may therefore most likely not be postponed without compromising the patient's visual prognosis.
The British journal of ophthalmology, Jan 18, 2016
To explore the application of intraoperative wavefront aberrometry (IWA) for aphakia-based biomet... more To explore the application of intraoperative wavefront aberrometry (IWA) for aphakia-based biometry using three existing formulae derived from autorefractive retinoscopy and introducing new improved formulae. In 74 patients undergoing cataract surgery, three repeated measurements of aphakic spherical equivalent (SE) were taken. All measurements were objectively graded for their quality and evaluated with the 'limits of agreement' approach. ORs were calculated and analysis of variance was applied. The intraocular lens (IOL) power that would have given the target refraction was back-calculated from manifest refraction at 3 months postoperatively. Regression analysis was performed to generate two aphakic SE-based formulae for predicting this IOL. The accuracy of the formulae was determined by comparing them to conventional biometry and published aphakia formulae. In 32 eyes, three consecutive aphakic measurements were successful. Objective parameters of IWA map quality signific...
To evaluate the effect of corneal cross-linking (CXL) in progressive keratoconus by applying in v... more To evaluate the effect of corneal cross-linking (CXL) in progressive keratoconus by applying in vivo static and dynamic Scheimpflug analyses. In this longitudinal retrospective study, corneal topography and tomography (Pentacam HD) and dynamic Scheimpflug-based biomechanical analyses (CorvisST [CST]) of 24 eyes of 24 patients with progressive keratoconus before and 6 months after CXL were reviewed. New dynamic curve analyses, provided by Oculus Optikgeräte, were performed to analyze corneal dynamics throughout the entire response to the CST air puff impulse. Besides subtle changes of topography and tomography, only the CorvisST predefined parameters peak distance (-0.5 mm) and radius of the intended cornea (+0.5 mm; P < .05) demonstrated statistically significant differences 6 months after CXL. Using new dynamic curve analyses, additional distinct changes of the corneal biomechanical characteristics after CXL were noted. Published results of corneal biomechanical changes after CXL for progressive keratoconus based on single, predefined CST parameters are inconsistent. The new dynamic curve analyses demonstrate distinct changes of the biomechanical properties of the cornea and might therefore be the next step in understanding in vivo analyses of corneal biomechanics. [J Refract Surg. 2016;32(1):34-39.].
To improve keratoconus (KC) screening with new in vivo biomechanical Scheimpflug analyses. After ... more To improve keratoconus (KC) screening with new in vivo biomechanical Scheimpflug analyses. After adjusting for intraocular pressure and corneal thickness, predefined static and new dynamic Scheimpflug curve analyses [Pentacam HR and Corvis ST (CST); Oculus] of 87 normal eyes, 27 subclinical KC eyes, 42 suspected KC, and 65 manifest KC eyes were reviewed retrospectively. A t test (for a normal distribution), Wilcoxon matched-pairs test (if not normally distributed), and receiver operating characteristics were used to test for statistically significant differences between these groups. In addition, new dynamic curve analyses were performed to analyze corneal dynamics throughout the entire response to the CST air puff impulse. Comparing normal and KC-suspect eyes, the parameters A1 length, A2 length, radius of the inward-bended cornea, and deflection length at the highest concavity revealed statistically significant differences. In addition, the newly calculated "applanation length level" and "deflection length level" demonstrated consistently increasing differences with increasing statistical significance between normal eyes and those with advancing KC stages. However, when comparing normal and subclinical KC eyes, none of the analyzed parameters demonstrated statistically significant differences. In vivo biomechanical analyses (CST) at their current state only marginally improve KC screening protocols. Newly generated parameters such as the applanation length level and deflection length level might further improve early KC screening.
Es gibt allgemein bekannte Fallstricke bei der Wahl der geeigneten Behandlungsstrategie in der ho... more Es gibt allgemein bekannte Fallstricke bei der Wahl der geeigneten Behandlungsstrategie in der hornhautrefraktiven Chirurgie. Einer von ihnen ist der Konflikt zwischen den Modellen, die entweder nur auf dem topographischen oder subjektiven präoperativen Zylinder basieren.
To compare the effect of a rotating microkeratome (M2) and a linear microkeratome (SBK) on the ch... more To compare the effect of a rotating microkeratome (M2) and a linear microkeratome (SBK) on the change in the astigmatic component in eyes with preoperative plano refractive cylinder. University Medical Centre Hamburg-Eppendorf, Hamburg, Germany. Retrospective case series. An Allegretto excimer laser was used to perform laser ablation in myopic eyes of consecutive patients. The laser in situ keratomileusis (LASIK) procedure included mechanical flap preparation using a microkeratome, either a linear type with a single-use 90 μm head to create a nasal hinge or a rotating type with a single-use 90 μm head to create a superior hinge. The Alpins vector method was applied to describe the effects of LASIK on postoperative refractive cylinder. The study evaluated 1045 eyes of 852 patients. Although the mean overall efficacy and safety indices indicate the procedure was highly precise, safe, and efficient, there were statistically significant differences in surgically induced astigmatism (SIA) between the microkeratomes (P = .002). The postoperative refractive cylinder (ie, SIA) was 0.75 diopter (D) or more in 116 eyes (11.1%), 44 (12.8%) of 344 linear cases and 72 (10.3%) of 701 rotating cases. Independent of the type of microkeratome used, the SIA was slightly higher in eyes treated first; the mean magnitude of the induced astigmatism was 0.35 D. In approximately 10% of eyes with preoperative plano refractive myopia, the astigmatic component tended to be overcorrected. Nevertheless, independent of the type of microkeratome, the maximum mean magnitude of refractive cylinder documented was 0.35 D. No author has a financial or proprietary interest in any material or method mentioned.
In eyes with a preoperative plano refractive cylinder, it would appear that there is no rationale... more In eyes with a preoperative plano refractive cylinder, it would appear that there is no rationale for astigmatic treatment. The aim of this retrospective, cross-sectional data analysis was to determine the amount of topographic astigmatism in refractive plano eyes that results in reduced efficacy after myopic laser in situ keratomileusis (LASIK). This study included 267 eyes from 267 consecutive myopic patients with a refractive plano cylinder. Receiver operating characteristic analysis was used to find the cut-off values of preoperative ocular residual astigmatism (= topographic astigmatism) that can best discriminate between groups of efficacy and safety indices in preoperative plano refractive cylinder eyes. Preoperative ocular residual astigmatism (ORA) (or topographic astigmatism) of ≤0.9 diopters (D) resulted in an efficacy index of at least 0.8 statistically significantly more frequently than eyes with a preoperative ORA of >0.9 D. Eyes with a high ORA preoperatively also ...
PURPOSE: We aimed to determine the incidence of buttonhole after laser in situ keratomileusis (LA... more PURPOSE: We aimed to determine the incidence of buttonhole after laser in situ keratomileusis (LASIK). We also evaluated possible risk factors, treatment strategies and visual outcome. SETTING: multicentric, including several international clinics. METHODS: : In this comparative case series we reviewed the medical records of 164,603 patients (315,259 eyes) that underwent LASIK from January 2003 to December 2011 to identify cases of buttonhole. All surgeries were performed by means of a manual microkeratome. The main outcome measures were incidence of buttonhole after LASIK, response to treatment and visual outcome. Possible risk factors, clinical course, days to retreatment and surgical treatment were recorded. RESULTS: Buttonhole was found in 137 eyes in 134 patients (105 myopes and 32 hyperopes). Age, preoperative refraction and keratometric power were not statistically significant independent risk factors. Buttonholes appeared in thinner corneas. Patients were retreated with a ne...
To analyse tomographic changes in eyes classified as &amp... more To analyse tomographic changes in eyes classified as 'normal', 'keratoconus-suspect' and 'clinically manifest keratoconus' based on the established KISA% definition of Rabinowitz and Rasheed and to develop the category of 'subclinical keratoconus eyes' to expand the classification into a 'subtopographic' range. Tomographic and topographic analyses of 670 eyes performed with a rotating Scheimpflug imaging system (Pentacam(®) , Oculus Inc., Wetzlar, Germany) were retrospectively analysed. Based on the KISA% keratoconus classification system, eyes were assigned to a 'normal', 'keratoconus-suspect' or 'manifest keratoconus' group. In addition, a new group of 'subclinical keratoconus eyes' was analysed, comprising unsuspicious fellow eyes of patients with keratoconus. T-tests, Wilcoxon rank-sum test, receiver operating characteristics (ROC) and robust regression analyses were performed to correlate tomographic parameters with the increasing KISA% index. KISA%-grouped keratoconus eyes showed robust tomographic changes. By adding the subclinical group, although the concurrent topography was unchanged, we were able to demonstrate statistically significant changes for almost all tomographic parameters (parameters with highest sensitivity/specificity: ART_max, [0.69/0.69], BAD_D [0.66/0.66]). The highest coefficient of determination (R(2) ) with the KISA% index was demonstrated for Ele_f_max (R(2) = 0.70), Ele_f_TP (R(2) = 0.69), Ele_b_TP (R(2) = 0.69) and BAD_D (R(2) = 0.68). We recommend the use of the expanded KISA% index (eKISA% index) as the basis for the definition of keratoconus and normal groups in future keratoconus research projects.
To examine the impact of temperature and sunlight duration on refractive and visual outcome of la... more To examine the impact of temperature and sunlight duration on refractive and visual outcome of laser-assisted in situ keratomileusis (LASIK) in myopic eyes. University Medical Center Hamburg-Eppendorf, Germany, and Care Vision Refractive Centers, Germany. Retrospective, cross-sectional data analysis. This study comprised 1,052 eyes of 1,052 consecutive myopic patients (419 males, 633 females; mean age at surgery 35.0±9.0 years) with a mean preoperative refractive spherical equivalent (SE) of -3.88±1.85 diopters (D). Two subgroups were defined, comprising patients undergoing surgery during either meteorological winter or summer. Manifest refraction, uncorrected, and corrected distant visual acuity (UDVA and CDVA) were assessed pre- and postoperatively. We applied robust regression analysis with efficiency index (EI), safety index (SI), and postoperative SE (in D) as dependent variables. At the 1-month (33.0±5.0 days) follow-up, the mean postoperative SE was -0.18±0.44 D. Bivariate co...
To examine the impact of seasonality on the refractive and visual outcomes of laser in situ kerat... more To examine the impact of seasonality on the refractive and visual outcomes of laser in situ keratomileusis (LASIK) in myopic eyes. Department of Ophthalmology and Care Vision Refractive Centers, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. Retrospective cross-sectional data analysis. Two subgroups were defined. The first comprised patients having surgery during meteorological winter and the second, patients having surgery during meteorological summer. The manifest refraction and uncorrected and corrected visual acuities were assessed preoperatively and postoperatively. Robust regression analysis was applied with the efficacy index, safety index, and postoperative SE as dependent variables. This study comprised 1052 eyes of 1052 consecutive myopic patients (419 men, 633 women; mean age at surgery 35.0 years ± 9.0 [SD]) with a mean preoperative refractive spherical equivalent (SE) of -3.88 ± 1.85 diopters (D). At the 1-month follow-up (mean 33.0 ± 5.0 days), the mean...
To provide the first clinical data in determining the feasibility, quality and precision of intra... more To provide the first clinical data in determining the feasibility, quality and precision of intraoperative wavefront aberrometry (IWA)-based refraction in patients with cataract. IWA refraction was recorded at 7 defined measurement points during standardised cataract surgery in 74 eyes of 74 consecutive patients (mean age 69±11.3 years). Precision and measurement quality was evaluated by the 'limits of agreement' approach, regression analysis, correlation analysis, Analysis of variance (ANOVA) and ORs for predicting measurement failure. Wavefront map (WFM) quality was objectivised and compared with the Pentacam Nuclear Staging analysis. Out of 814 IWA measurement attempts, 462 WFMs could be obtained. The most successful readings (n=63) were achieved in aphakia with viscoelastic. The highest (50.63%, SD 20.23) and lowest (29.19%, SD 13.94) quality of WFMs across all measurement points were found after clear corneal incision and in pseudophakia with viscoelastic, respectively....
Arch Soc Esp Oftalmol 2018;93(2):60-68., Jun 1, 2018
PURPOSE:
To assess visual outcomes of retreatment after laser in situ keratomileusis (LASIK) by l... more PURPOSE: To assess visual outcomes of retreatment after laser in situ keratomileusis (LASIK) by lifting the flap or performing photorefractive keratectomy (PRK) on the flap, as well as to establish whether there was an increased risk of epithelial ingrowth (EIG) when LASIK and lifting of the flap are separated by a long time interval and to determine the incidence of corneal haze after PRK.
METHODS: Retrospective study of 4077 patients (5468 eyes) who underwent LASIK and subsequent retreatment were reviewed in order to study their visual results and identify cases of EIG and corneal haze.
RESULTS: Enhancements included 5196 eyes from 3876 patients that were retreated by lifting the flap, and 272 eyes from 201 patients that were retreated by PRK on the flap. No statistically significant differences were found between the retreatments in terms of predictability, efficacy, and safety. A total of 704 cases of EIG were found after lifting the flap, for which surgical cleansing was necessary in 70. Surgical cleansing decreased the efficacy index when compared with patients with EIG who did not need cleansing (P=.01). Differences in terms of safety and predictability were not statistically significant. The incidence of corneal haze after ablation of the surface of the previous flap was 14.34%, although none of these cases were clinically relevant.
CONCLUSIONS: Visual outcomes were similar between patients who were retreated by lifting the flap and those who underwent PRK. The incidence of EIG when the flap was lifted was 13.55%. The incidence of EIG increases with the time elapsed between the primary procedure and retreatment.
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Papers by Toam Katz
To assess visual outcomes of retreatment after laser in situ keratomileusis (LASIK) by lifting the flap or performing photorefractive keratectomy (PRK) on the flap, as well as to establish whether there was an increased risk of epithelial ingrowth (EIG) when LASIK and lifting of the flap are separated by a long time interval and to determine the incidence of corneal haze after PRK.
METHODS:
Retrospective study of 4077 patients (5468 eyes) who underwent LASIK and subsequent retreatment were reviewed in order to study their visual results and identify cases of EIG and corneal haze.
RESULTS:
Enhancements included 5196 eyes from 3876 patients that were retreated by lifting the flap, and 272 eyes from 201 patients that were retreated by PRK on the flap. No statistically significant differences were found between the retreatments in terms of predictability, efficacy, and safety. A total of 704 cases of EIG were found after lifting the flap, for which surgical cleansing was necessary in 70. Surgical cleansing decreased the efficacy index when compared with patients with EIG who did not need cleansing (P=.01). Differences in terms of safety and predictability were not statistically significant. The incidence of corneal haze after ablation of the surface of the previous flap was 14.34%, although none of these cases were clinically relevant.
CONCLUSIONS:
Visual outcomes were similar between patients who were retreated by lifting the flap and those who underwent PRK. The incidence of EIG when the flap was lifted was 13.55%. The incidence of EIG increases with the time elapsed between the primary procedure and retreatment.