W. Wiegand

Measurement of viscoelastic corneal parameters (corneal hysteresis) in patients with primary open angle glaucoma

BACKGROUND The ocular response analyzer (ORA) uses an air-pressure-triggered, dynamic, bi-directional corneal applanation method to measure biomechanical parameters of the cornea. Corneal hysteresis (CH) is defined as the difference in intraocular pressure recorded during inward and outward applanation. CH is therefore an indicator for the viscoelastic properties of the cornea. PATIENTS AND METHODS CH was recorded in non-glaucoma patients (80 eyes) as well as in patients with primary open angle glaucoma (POAG, 82 eyes). The correlation between CH and central corneal thickness (CCT) was analyzed. RESULTS Mean CH was 10.6+/-2.2 mmHg in the non-glaucoma group and 9.3+/-2.2 mmHg in patients with POAG (p<0.01). CH and CCT showed a positive correlation in non-POAG patients, however no such correlation was found in the POAG group. CONCLUSION Patients with POAG show an alteration of biomechanical corneal parameters with a significant decrease in corneal hysteresis. A positive correlation between CH and CCT, which was seen in the non-glaucoma group could not be detected in the POAG group.

Bestimmung viskoelastischer Hornhauteigenschaften (korneale Hysterese) bei Patienten mit primärem Offenwinkelglaukom

BACKGROUND The ocular response analyzer (ORA) uses an air-pressure-triggered, dynamic, bi-directional corneal applanation method to measure biomechanical parameters of the cornea. Corneal hysteresis (CH) is defined as the difference in intraocular pressure recorded during inward and outward applanation. CH is therefore an indicator for the viscoelastic properties of the cornea. PATIENTS AND METHODS CH was recorded in non-glaucoma patients (80 eyes) as well as in patients with primary open angle glaucoma (POAG, 82 eyes). The correlation between CH and central corneal thickness (CCT) was analyzed. RESULTS Mean CH was 10.6+/-2.2 mmHg in the non-glaucoma group and 9.3+/-2.2 mmHg in patients with POAG (p<0.01). CH and CCT showed a positive correlation in non-POAG patients, however no such correlation was found in the POAG group. CONCLUSION Patients with POAG show an alteration of biomechanical corneal parameters with a significant decrease in corneal hysteresis. A positive correlation between CH and CCT, which was seen in the non-glaucoma group could not be detected in the POAG group.

Anatomische und funktionelle Ergebnisse nach elektiver Makulachirurgie

ZusammenfassungHintergrundDie funktionellen und anatomischen Ergebnisse nach elektiver Makulachirurgie sollen untersucht werden.Methoden381 Augen, die aufgrund eines Macular pucker (n=244) oder eines Makulaforamens (n=137) einer Standard-Pars-plana-Vitrektomie (PPV) mit hinterer GK-Abhebung, Membrane peeling (ohne ICG-Anfärbung) und einer SF6-Instillation in dem Zeitraum von 6/1995 und 12/2001 unterzogen worden sind, wurden retrospektiv ausgewertet.ErgebnisseIn der untersuchten Gruppe musste ein Zweiteingriff aufgrund einer visusbedrohenden Komplikation in 8/381=2,1% der Fälle durchgeführt werden. Bei den Patienten mit Macular pucker besserten sich die Metamorphopsien in 46,6%, der Median des Visus stieg von präoperativ 0,3 auf 0,5 postoperativ an. Die primäre Verschlussrate der Makulaforamina lag bei 92,2%, der Median des Visus aller operierten Augen stieg von 0,2 präoperativ auf 0,4 postoperativ an.SchlussfolgerungIn unserem Kollektiv wurde in nur 8/381 Augen (2,1%) ein vitreoretinaler Zweiteingriff aufgrund einer visusbedrohenden Komplikation nach elektiver Makulachirurgie notwendig. Im Vergleich zum Spontanverlauf beeinflusst die PPV den funktionellen Verlauf sehr günstig.AbstractPurposeThe purpose of this paper is to assess the anatomical and functional results after macular surgery in a large group of patients.MethodsBetween June 1995 and December 2001, 381 eyes underwent vitreous surgery for macular pucker (n=244) or macular holes (n=137) with a standard pars plana vitrectomy (PPV) with induction of posterior vitreous separation, membrane peeling, peeling of the internal limiting membrane (no ICG staining was used), and gas instillation (SF6).ResultsA second surgical intervention due to vision-threatening complications after PPV had to be performed in 8 of 381=2.1%. In the macular pucker group, metamorphopsias improved in 46.6% and the median of visual acuity (VA) improved from preoperative 0.3 to postoperative 0.5. Hole closure of macular holes was obtained in 92.2%; the median of VA improved in this group from preoperative 0.2 to postoperative 0.4.ConclusionIn our group a second vitreoretinal procedure due to vision-threatening complications had to be performed in 2.1%. Compared to the spontaneous course, PPV for macular pucker or macular hole has a very positive influence on functional parameters.

Anatomical and functional results after elective macular surgery

ZusammenfassungHintergrundDie funktionellen und anatomischen Ergebnisse nach elektiver Makulachirurgie sollen untersucht werden.Methoden381 Augen, die aufgrund eines Macular pucker (n=244) oder eines Makulaforamens (n=137) einer Standard-Pars-plana-Vitrektomie (PPV) mit hinterer GK-Abhebung, Membrane peeling (ohne ICG-Anfärbung) und einer SF6-Instillation in dem Zeitraum von 6/1995 und 12/2001 unterzogen worden sind, wurden retrospektiv ausgewertet.ErgebnisseIn der untersuchten Gruppe musste ein Zweiteingriff aufgrund einer visusbedrohenden Komplikation in 8/381=2,1% der Fälle durchgeführt werden. Bei den Patienten mit Macular pucker besserten sich die Metamorphopsien in 46,6%, der Median des Visus stieg von präoperativ 0,3 auf 0,5 postoperativ an. Die primäre Verschlussrate der Makulaforamina lag bei 92,2%, der Median des Visus aller operierten Augen stieg von 0,2 präoperativ auf 0,4 postoperativ an.SchlussfolgerungIn unserem Kollektiv wurde in nur 8/381 Augen (2,1%) ein vitreoretinaler Zweiteingriff aufgrund einer visusbedrohenden Komplikation nach elektiver Makulachirurgie notwendig. Im Vergleich zum Spontanverlauf beeinflusst die PPV den funktionellen Verlauf sehr günstig.AbstractPurposeThe purpose of this paper is to assess the anatomical and functional results after macular surgery in a large group of patients.MethodsBetween June 1995 and December 2001, 381 eyes underwent vitreous surgery for macular pucker (n=244) or macular holes (n=137) with a standard pars plana vitrectomy (PPV) with induction of posterior vitreous separation, membrane peeling, peeling of the internal limiting membrane (no ICG staining was used), and gas instillation (SF6).ResultsA second surgical intervention due to vision-threatening complications after PPV had to be performed in 8 of 381=2.1%. In the macular pucker group, metamorphopsias improved in 46.6% and the median of visual acuity (VA) improved from preoperative 0.3 to postoperative 0.5. Hole closure of macular holes was obtained in 92.2%; the median of VA improved in this group from preoperative 0.2 to postoperative 0.4.ConclusionIn our group a second vitreoretinal procedure due to vision-threatening complications had to be performed in 2.1%. Compared to the spontaneous course, PPV for macular pucker or macular hole has a very positive influence on functional parameters.

Changes in glare and contrast sensitivity after PRK

SummaryBackground: Morphological changes in the corneal surface after PRK may result not only in refraction fluctuations and reduction in visual acuity, but also in changes of contrast sensitivity. The aim of this study was to investigate whether PRK has an influence on contrast sensitivity with and without glare with a subsequent effect on the ability to drive cars. Patients and methods: Anonymous inquiries were made by means of a questionnaire sent to 114 patients after bilateral PRK in which the patients were asked to assess subjectly their driving ability. Additionally, in 66 eyes of 66 patients with a mean myopia of −5.3 D, an investigation on contrast sensitivity was performed according to the recommendations of the DOG (German Ophthalmological Society) using a Rodenstock nyctometer. Results: Postoperatively, 55 % of the patients felt more comfortable driving a car than preoperatively, 31 % did not recognize any change, and 14 % felt more uncomfortable driving car. Contrast sensitivity with or without glare 2 weeks postoperatively was so much reduced in 77 % or 53 %, respectively, of the patients that the criteria for driving a car in Germany were not fulfilled.Within the first 12 months after PRK the number of impaired patients diminished but even 1 year after PRK the number of patients with reduced contrast sensitivity with and without glare was higher than before PRK. Surprisingly, however, the criteria for driving a car with respect to contrast sensitivity with and without glare were not fulfilled even before PRK by as much as 44 % and 24 % of the patients, respectively. Conclusions: All patients must be in formed about the possible impairment for driving a car before PRK is performedZusammenfassungFragestellung: Bei einer PRK kommt es zu morphologischen Veränderungen an der Hornhautoberfläche, die nicht nur Refraktionsschwankungen und eine Visusherabsetzung, sondern auch eine Reduktion der Kontrastempfindlichkeit nach sich ziehen können. In dieser Studie sollte geklärt werden, ob und inwieweit durch eine PRK bei myopen Patienten eine subjektive Beeinflussung der Fahrtauglichkeit eintritt und inwieweit sich Veränderungen des Dämmerungssehvermögens mit und ohne Blendung nach einer PRK nachweisen lassen. Patienten und Methoden: Bei 114 myopen Patienten wurde nach beidseitiger PRK eine anonyme Umfrage mittels eines vorgegebenen Fragebogens durchgeführt, die die subjektive Einschätzung der Fahrtauglichkeit vor und nach PRK betraf. Ferner wurde bei 66 Augen von 66 Patienten mit einem sphärischen Mittel der Ausgangsrefraktion von −5,3 dpt das Dämmerungssehen mit und ohne Blendung vor und nach der PRK entsprechend den Empfehlungen der Deutschen Ophthalmologischen Gesellschaft (DOG) am Nyktometer der Firma Rodenstock untersucht. Ergebnisse: Bei der anonymen Umfrage gaben 55 % der Patienten an, daß das Autofahren nach beidseitiger PRK angenehmer sei als vorher, 31 % hatten keine Veränderung bemerkt und 14 % der Patienten gaben eine Verschlechterung an. Bei der Untersuchung am Nyktometer zeigte sich, daß das Dämmerungssehen ohne bzw. mit Blendung zwei Wochen postoperativ im Durchschnitt bei 53 % bzw. 77 % der Patienten so weit eingeschränkt war, daß die Bedingungen für die Fahrerlaubnis der Klasse 3 nicht erfüllt waren. Im Laufe der folgenden 12 Monate kam es zwar zu einer allmählichen Verbesserung des Dämmerungssehens ohne und mit Blendung, jedoch lag auch nach Ablauf eines Jahres der Anteil der beeinträchtigten Patienten deutlich höher als vor der PRK. Erstaunlich war allerdings, daß bereits präoperativ die Bedingungen der Fahrerlaubnis Klasse 3 hinsichtlich des Dämmerungssehens ohne Blendung bei 24 % der Patienten und hinsichtlich des Dämmerungssehens mit Blendung bei 44 % der Patienten nicht erfüllt waren. Schlußfolgerung: Eine ausreichende Aufklärung aller Patienten über diese möglichen Beeinträchtigungen des Sehvermögens beim Führen eines Kraftfahrzeuges ist dringend erforderlich.

Hornhautdickenabhängige Korrekturfaktoren bei der Goldmann-Applanationstonometrie

BACKGROUND For many years researchers have discussed which corneal parameters can influence the measurement of intraocular pressure (IOP). As a substantial parameter, the central corneal thickness (CCT) is assumed; however, different measuring methods - including Goldmann applanation tonometry (GAT), dynamic contour tonometry (DCT), and corneal compensated pressure measured with the ocular response analyzer (IOPcc) - may lead to a completely different dependence on corneal thickness. METHOD In a study approved by the ethics commission, the anterior chamber of 92 eyes of cataract patients and 85 eyes of glaucoma patients with very different CCT measurements was cannulized before surgery (cataract operation or trabeculectomy), and the IOP values were measured simultaneously with a pressure absorber and with GAT (Perkins tonometer) at different pressure values. RESULTS The individual measurements exhibited an extraordinarily wide dispersion. In both groups, weak correlations of the difference between GAT and IOP values with the CCT were found (correction factors of 0.95 mmHg/100 microm CCT at pressure level 20 mmHg, 1.2 mmHg/100 microm CCT at pressure level 30 mmHg, and 1.7 mmHg/100 microm CCT at pressure level 40 mmHg). CONCLUSIONS Measurement of CCT is valuable for prognostic assessment of glaucoma, but not for correction factors for corneal thickness.

Correction factors for central corneal thickness in Goldmann applanation tonometry

BACKGROUND For many years researchers have discussed which corneal parameters can influence the measurement of intraocular pressure (IOP). As a substantial parameter, the central corneal thickness (CCT) is assumed; however, different measuring methods - including Goldmann applanation tonometry (GAT), dynamic contour tonometry (DCT), and corneal compensated pressure measured with the ocular response analyzer (IOPcc) - may lead to a completely different dependence on corneal thickness. METHOD In a study approved by the ethics commission, the anterior chamber of 92 eyes of cataract patients and 85 eyes of glaucoma patients with very different CCT measurements was cannulized before surgery (cataract operation or trabeculectomy), and the IOP values were measured simultaneously with a pressure absorber and with GAT (Perkins tonometer) at different pressure values. RESULTS The individual measurements exhibited an extraordinarily wide dispersion. In both groups, weak correlations of the difference between GAT and IOP values with the CCT were found (correction factors of 0.95 mmHg/100 microm CCT at pressure level 20 mmHg, 1.2 mmHg/100 microm CCT at pressure level 30 mmHg, and 1.7 mmHg/100 microm CCT at pressure level 40 mmHg). CONCLUSIONS Measurement of CCT is valuable for prognostic assessment of glaucoma, but not for correction factors for corneal thickness.

Bestimmung viskoelastischer Hornhauteigenschaften (korneale Hysterese) bei Patienten mit primärem Offenwinkelglaukom@@@Measurement of viscoelastic corneal parameters (corneal hysteresis) in patients with primary open angle glaucoma.

BACKGROUND The ocular response analyzer (ORA) uses an air-pressure-triggered, dynamic, bi-directional corneal applanation method to measure biomechanical parameters of the cornea. Corneal hysteresis (CH) is defined as the difference in intraocular pressure recorded during inward and outward applanation. CH is therefore an indicator for the viscoelastic properties of the cornea. PATIENTS AND METHODS CH was recorded in non-glaucoma patients (80 eyes) as well as in patients with primary open angle glaucoma (POAG, 82 eyes). The correlation between CH and central corneal thickness (CCT) was analyzed. RESULTS Mean CH was 10.6+/-2.2 mmHg in the non-glaucoma group and 9.3+/-2.2 mmHg in patients with POAG (p<0.01). CH and CCT showed a positive correlation in non-POAG patients, however no such correlation was found in the POAG group. CONCLUSION Patients with POAG show an alteration of biomechanical corneal parameters with a significant decrease in corneal hysteresis. A positive correlation between CH and CCT, which was seen in the non-glaucoma group could not be detected in the POAG group.

Hornhautdickenabhängige Korrekturfaktoren bei der Goldmann-Applanationstonometrie@@@Correction factors for central corneal thickness in Goldmann applanation tonometry

BACKGROUND For many years researchers have discussed which corneal parameters can influence the measurement of intraocular pressure (IOP). As a substantial parameter, the central corneal thickness (CCT) is assumed; however, different measuring methods - including Goldmann applanation tonometry (GAT), dynamic contour tonometry (DCT), and corneal compensated pressure measured with the ocular response analyzer (IOPcc) - may lead to a completely different dependence on corneal thickness. METHOD In a study approved by the ethics commission, the anterior chamber of 92 eyes of cataract patients and 85 eyes of glaucoma patients with very different CCT measurements was cannulized before surgery (cataract operation or trabeculectomy), and the IOP values were measured simultaneously with a pressure absorber and with GAT (Perkins tonometer) at different pressure values. RESULTS The individual measurements exhibited an extraordinarily wide dispersion. In both groups, weak correlations of the difference between GAT and IOP values with the CCT were found (correction factors of 0.95 mmHg/100 microm CCT at pressure level 20 mmHg, 1.2 mmHg/100 microm CCT at pressure level 30 mmHg, and 1.7 mmHg/100 microm CCT at pressure level 40 mmHg). CONCLUSIONS Measurement of CCT is valuable for prognostic assessment of glaucoma, but not for correction factors for corneal thickness.

Beidseitige Panuveitis mit Papillenschwellung@@@Bilateral panuveitis with papillary swelling

Lues (syphilis) is a chronic cyclic infectious disease which can continue for decades if untreated. A simultaneous HIV infection can result in false negative results in serological tests for lues. The occurrence of neurolues has frequently been described in HIV positive patients. In the differential diagnosis an early ocular manifestion of lues should be considered. A 40-year-old homosexual patient presented in our hospital with bilateral pain-free increasing loss of vision. The ophthalmological examination revealed an intermediately expressed panuveitis with streaky opacity of the vitreous body and pronounced bilateral papillary swelling. Following systemic anti-inflammatory therapy with cortisone the situation worsened after initial improvement. The serological investigations revealed both HIV and lues infections. Intravenous therapy with mega units of penicillin led to a slow improvement of clinical symptoms and also vision. In cases of uveitis of unclear origin together with a HIV infection and suspected lues, regular serological testing should be carried out because the occurrence of late complications of lues can be avoided by the diagnosis of lues and adequate treatment.