Protein changes in the human lens during development of senile nuclear cataract.

Senile nuclear cataractous lenses were divided into three groups of increasing nuclear color. These groups were considered as successive stages in the development of senile nuclear cataract. The cortex and the nucleus of normal and cataractous lenses were separated into water-soluble, urea-soluble and urea-insoluble fractions. Fractionation on a Sephadex G-200 column of the water-soluble components revealed five protein fractions for both cortex and nucleus. Only minor quantitative differences in polypeptide chain composition were found by isoelectric focusing between corresponding protein fractions isolated from normal and cataractous lenses. The weight percentages of the water-soluble, urea-soluble, and urea-insoluble fractions of cortex and nucleus from the normal and cataractous lenses were determined. A decrease of the amounts of the water-soluble and urea-soluble fractions and a concomitant increase of the urea-insoluble fraction were observed in the nucleus as a function of cataract development. Lens wet weight and protein content did not change significantly. The carbohydrate content of the urea-soluble fractions increased, that of the urea-insoluble fraction decreased. A striking decrease of the phospholipid content in the urea-insoluble fraction was found.

Pyrolysis mass spectra, sulfhydryl and tryptophan content of the embryonic nuclei from adult human normal and nuclear-cataractous lenses.

Cataractous state-related alterations were studied by Curie-point pyrolysis low voltage mass spectrometry performed on the embryonic nuclei from adult normal and nuclear-cataractous human lenses. It was shown that the relative intensities of ion signals assigned to sulfur dioxide and tentatively, to other sulfur oxidation products correlate with the increase in lens nuclear color. Since these ion signals may represent pyrolysis fragments from methionine sulfoxide, methionine sulfone, cysteic acid and disulfide compounds present in the parent material, it is concluded that progressive oxidation of sulfur compounds appears to take place during nuclear cataractogenesis. Automated pyrolysis mass spectrometry coupled with multivariate analysis of the spectral data by computer turned out to be a rapid method of characterizing sub-milligram samples of lens material. The results were supported by data obtained by conventional determination of sulfhydryl and tryptophan groups.

Gas chromatographic and mass spectroscopic analysis of excimer and erbium: yttrium aluminum garnet laser-ablated human cornea.

The photoablative products from human cadaver corneas treated with lasers were investigated using gas chromatography and mass spectroscopy. The photoablations were done separately with an excimer laser (193 nm) and with an erbium: yttrium aluminum garnet (Er:YAG) laser (2.94 microns). More than 20 different types of molecules with a molecular weight of 40-400 mass units could be identified, most of which were found to be alkanes. The comparison of the two types of laser ablations showed larger fragments and fewer types of molecules present after excimer laser treatment than after Er:YAG photoablation.

Autoradiographic mapping of the glucose transporter with cytochalasin B in the mammalian eye.

The anatomic localization of the glucose transport protein in the eyes of rats, rabbits, baboons, marmosets, and humans with [3H]cytochalasin B using in vitro autoradiography showed high densities of glucose carrier densities. These densities were seen in the ciliary body, especially ciliary processes, iris, retina, and in some species, the trabecular meshwork and lens. In the lens, specific [3H]cytochalasin B-binding sites were mainly concentrated in the lens nucleus. Lower concentrations were found in the cortex. During aging, glucose transporter concentration increases up to the age of 8 yr in the marmoset lens nucleus, but decreases in the cortex and retina. Moderate amounts of carrier are located in the corneal endothelium and epithelium. The enrichment of glucose carrier protein in the trabecular meshwork suggests a high metabolic activity and a possible relationship in the regulation of intraocular pressure.

Non-tryptophan fluorescence of crystallins from normal and cataractous human lenses.

The soluble proteins of a newborn human lens exhibit almost no non-tryptophan fluorescence. On aging, an increase in the fluorescence of all native crystallins is found except for gamma 2-crystallin. With formation of nuclear cataract, a further increase is seen for gamma 1-crystallin. The fluorophore, excitation 355 nm/emission 420 nm, is mainly associated with one species of the gamma 1-crystallin population. It is also present as such in the soluble fraction and increases significantly with nuclear cataract formation. At least one of the gamma 1-crystallins seems to play an important role in the cataractogenic process.

Combined phacoemulsification and filtering surgery with the 'no-stitch' technique.

OBJECTIVE: To determine if intentionally making a radial incision could lead to a lasting decrease in intraocular pressure and the development of filtering blebs. METHODS: Forty-three eyes treated with combined filtering surgery were compared with a control group of 42 eyes treated with cataract surgery (phacoemulsification) alone. All of the patients had advanced chronic open-angle glaucoma. During combined cataract and glaucoma surgery, the tunnel floor was transected with Vannas scissors. RESULTS: One year after surgery, the mean intraocular pressure in the study group decreased 7.6 mm Hg from a preoperative mean (+/-SD) of 25.9+/-5.3 mm Hg. The decrease in the control group was 3.7+/-4.2 mm Hg. The difference between the 2 groups was statistically significant (P<.001). In the study group, an average of 1.5+/-0.8 fewer medications were required 1 year after surgery. In the control group, 0.5+/-0.6 fewer medications were required. CONCLUSIONS: The combined surgical procedure discussed in this article led to a lasting decrease in intraocular pressure. Cataract surgery alone using the no-stitch technique and posterior chamber lens implantation also reduced intraocular pressure, although significantly less.

Corneal endothelial cell changes in pseudoexfoliation syndrome after cataract surgery.

OBJECTIVE: To characterize possible differences in endothelial cell changes after cataract surgery in patients with pseudoexfoliation syndrome (PSX). METHODS: In this prospective, age-matched, controlled clinical study, 25 consecutive patients with PSX and 25 control patients with senile cataracts only were studied. All patients were treated with standardized cataract surgery. Sequential quantitative and qualitative morphometric endothelial cell analyses of the central and paracentral cornea were performed preoperatively and postoperatively at 1 day, 4 weeks, and 6 months using noncontact specular microscopy. RESULTS: Preoperative endothelial cell counts were 9.9% (P<.05) lower in patients with PSX (2387+/-266 cells/mm2) than in controls (2648+/-349 cells/mm2). The mean endothelial cell loss was 11.1% in the PSX group and 10.3% (P<.001 for both) in the control group, with no intergroup differences after 6 months. The mean endothelial cell area increased in both groups. Also, qualitative analysis revealed no significant differences in the endothelial repair mechanisms. CONCLUSIONS: Endothelial cell density is reduced preoperatively in patients with PSX compared with age-matched controls. In patients with PSX, cataract surgery induced similar endothelial cell changes without increased endothelial cell loss postoperatively.

Excimer laser keratectomy for correction of astigmatism.

We treated 13 eyes (12 patients) with excimer laser surgery for correction of astigmatism using linear corneal T-excisions. All eyes were followed up for a minimum of three months. We used a newly developed delivery system and special contact masks to deliver the 193-nm excimer light. Astigmatic corrections of up to 4.16 diopters were obtained. The actual corrections corresponded well with the intended values as predicted by a biomechanical theory. The refractive change over time was different than that observed after knife incisions, suggesting different repair mechanisms. An epithelial plug filling the whole T-excision persisted for over one year in all eyes.

Erbium:YAG laser photoablation of human cornea.

PURPOSE: To determine whether the healing response of the human cornea after photoablation with a midinfrared solid-state laser was more pronounced than after excimer laser keratectomies because of the increased thermal damage in adjacent tissue. METHODS: We treated five blind human eyes with an erbium:YAG (Er:YAG) laser prototype and followed up the patients for nine months. RESULTS: Regarding epithelial healing and corneal clarity, the patients had a healing response very similar to that of excimer laser. Further clinical and experimental studies are necessary to estimate healing and regression.

Inadvertent use of chlorhexidine instead of balanced salt solution for intraocular irrigation.

In three consecutive cataract operations, chlorhexidine was inadvertently used as an intraocular irrigating solution as a result of inattentiveness of an assistant. In two of the three patients, corneal endothelium damage was so severe that penetrating keratoplasty had to be performed. Further effects included pronounced iris atrophy, anterior chamber applanation, and a retrocorneal membrane. In one case, an increase in intraocular pressure developed. No effects were observed in the retina or optic nerve. Inadvertently using chlorhexidine for intraocular irrigation has far-reaching consequences for the affected eye and is recognizable by streak formation in the anterior chamber when intraocular infusion is initiated. To avoid such mistakes, the markings of the two bottles should be of different colors.

Photovaporization rate and profile of an erbium-chromium:YAG laser in the fundamental mode.

PURPOSE: To evaluate the ablation characteristics of an experimental erbium:YAG (Er:YAG) laser and assess whether it delivers sufficient output for performing photorefractive keratectomy. SETTING: Department of Ophthalmology, Virchow-Clinics, Humboldt University, Berlin, Germany. METHODS: An experimental Er:YAG laser, the erbium-chromium:YAG, running in fundamental mode was used to evaluate the energy profile. Measurements obtained using a joulemeter were compared to the ablation profiles of cadaver pig eyes. The pig eyes were treated with different fluences (mean 0.8 to 2.9 J/cm2) and, after histological preparation, were examined using light and scanning electron microscopy. RESULTS: Measurements with the joulemeter and in the cadaver pig eyes showed a Gaussian-curved profile of energy (ablation). In the current setting, the diameter of ablation was 3.5 mm. Histological examination showed a homogeneous profile of ablation with minor thermal damage. CONCLUSION: The Er:YAG laser running in the fundamental mode allows homogeneous ablation of corneal tissue. The Er:YAG laser is easier to handle technically than the excimer laser and has none of the potential risks of ultraviolet light.

Postoperative astigmatism and relative strength of tunnel incisions: a prospective clinical trial.

PURPOSE: To investigate the influence of incision depth and site on wound strength and postoperative astigmatism. SETTING: Virchow Memorial Hospital Eye Clinic, Berlin, Germany. METHODS: In this prospective, randomized study, 180 patients with a 7.0 mm tunnel incision depth of 300 and 500 microns; limbal incision and scleral incision; temporal scleral incision and scleral incision at the 12 o'clock position; temporal limbal incision and limbal incision at the 12 o'clock position. Postoperative astigmatism was measured by keratometry and videokeratoscopy 1 day, 1 and 4 weeks, and 8 months postoperatively. Wound strength was measured with an ophthalmodynamometer on the first postoperative day and after 1 week at the site with the least mechanical stability adjacent and posterior to the primary incision. RESULTS: The temporal incision, which was performed 1.0 mm behind the surgical limbus, led to induced astigmatism of 0.65 diopters (D) +/- 0.23 (SD) after 8 months. When incision was at the 12 o'clock position, the induced astigmatism was 0.97 +/- 0.41 D. Induced astigmatism was highest following a limbal incision in the 12 o'clock position (1.33 +/- 0.63 D). This effect was less pronounced with a temporal incision. Incision depth did not significantly influence induced astigmatism. An incision depth of 500 microns led to induced astigmatism of 0.94 +/- 0.50 D; a depth of 300 microns led to induced astigmatism of 0.78 +/- 0.64 D. After 1 week, wound strength was highest with temporal scleral incisions (38.6 +/- 2.1 kPa by ophthalmodynamometer) and lowest with limbal incisions in the 12 o'clock position (30.8 +/- 7.7 kPa). CONCLUSIONS: Incisions site significantly influenced mechanical wound strength and induced astigmatism; incision depth influenced neither. In general, incisions in the 12 o'clock position induced more astigmatism than temporal incisions.

Effect of incision location on preoperative oblique astigmatism after scleral tunnel incision.

PURPOSE: To evaluate the effect of incision location or clinically relevant preoperative oblique astigmatism. SETTING: Department of Ophthalmology, Virchow Medical Center, Humboldt-University, Berlin, Germany. METHODS: This prospective study included 68 patients who had phacoemulsification and posterior chamber lens implantation using a standardized 7.0 mm self-sealing trapezoidal scleral tunnel incision. Each patient was randomly assigned to one of three incision locations: Group A, conventional superior incision; Group B, temporal incision; Group C, oblique incision centered on the steeper meridian (modified BENT incision). Astigmatism analysis was performed by manual keratometry and corneal topography. RESULTS: A significant mean reduction in astigmatism of 0.58 diopter (D) (P < .01) was achieved in only the modified BENT incision group. Postoperatively, significant flattening of 0.27 D (P < .01) in the steeper meridian as well as steepening of 0.29 D (P < .01) in the flatter meridian occurred. No decrease in astigmatism was noted in the superior or temporal incision groups. Five months postoperatively, vector analysis showed that surgically induced astigmatism was significantly higher in the superior incision group (1.16 D +/- 0.44 [SD]) than in the temporal incision group (0.66 +/- 0.32 D) or modified BENT incision group (0.82 +/- 0.50 D). Corneal topographic analysis confirmed these results within +/- 0.3 D. CONCLUSIONS: Only the oblique incision centered on the steeper meridian (modified BENT incision) effectively and predictably reduced preoperative oblique astigmatism. In eyes with clinically relevant oblique astigmatism, we recommend using a modified BENT incision.

Correcting postoperative astigmatism using curved lamellating keratotomy.

PURPOSE: To ascertain whether the change in refraction caused by paired lamellating corneal incisions in cadaver eyes could be achieved in living eyes and whether wound healing influences this effect. SETTING: Virchow Hospital Eye Clinic, Humboldt University, Berlin, Germany. METHODS: This prospective study included 45 patients who had a follow-up of 15 months. All had astigmatism of at least 2.00 diopters (D) induced by previous cataract surgery. Optical zones of 7.0 and 8.0 mm and chordal lengths of 3.0 and 5.0 mm were used. All incisions were paired. RESULTS: Mean preoperative astigmatism measured with a keratometer was 3.64 D +/- 0.89 (SD). After 15 months, it was 1.00 +/- 0.76 D, and mean induced astigmatism was 3.18 +/- 1.30 D. The 7.0 mm group had a mean induced astigmatism of 3.93 +/- 1.52 D, which was significantly higher than that in the 8.0 mm group (mean 2.60 +/- 0.74 D) at a uniform chordal length of 3.0 mm. Mean uncorrected visual acuity was 0.26 +/- 0.14 preoperatively and 0.50 +/- 0.28 after 15 months; mean corrected visual acuity improved from 0.58 +/- 0.21 to 0.76 +/- 0.21. Mean endothelial cell count was 1799 +/- 595 cells/mm2 preoperatively and 1784 +/- 589 cells/mm2 after 6 months; the difference was not significant. CONCLUSION: Curved lamellating keratotomy gives stable postoperative refractive results without significantly affecting endothelial cell count or visual acuity.

Comparison of a diffractive bifocal and a monofocal intraocular lens.

PURPOSE: To compare a Pharmacia diffractive bifocal intraocular lens (IOL) with a monofocal lens of the same design without the diffractive grating. SETTING: Multicenter study. METHODS: This randomized, prospective study comprised 70 patients with a monofocal IOL and 79 with a diffractive bifocal IOL. Follow-up was 5 to 6 months. Near and distance visual acuities, contract sensitivity, patient satisfaction, and spectacle use were evaluated. RESULTS: All patients achieved a best corrected visual acuity of 0.5 or better; 80% in the monofocal and 71% in the bifocal group had a best corrected visual acuity of 1.0 or better. Without correction, 93% of the bifocal and 9% of the monofocal group could read J3 or better. With distance correction, 99% and 4%, respectively, could read J3 or better. Contrast sensitivity was slightly lower in the bifocal group at distance and near for all spatial frequencies. In the bifocal group, 46% never used spectacles for near tasks. Overall satisfaction was rated good by 86% of the monofocal and 85% of the bifocal group. CONCLUSIONS: The diffractive bifocal IOL performed well at distance and near. Patients who no longer require spectacles will benefit significantly from a bifocal IOL, but many with a bifocal IOL in one eye will require spectacles for the fellow eye.

Contrast sensitivity after implantation of diffractive bifocal and monofocal intraocular lenses.

PURPOSE: To compare contrast sensitivity (CS) after implantation of a diffractive bifocal intraocular lens (IOL) and a monofocal IOL of similar design. SETTING: Seven European centers. METHODS: In this randomized, prospective study, CS was tested 5 months after cataract and IOL implantation surgery in 115 patients with a diffractive bifocal IOL and 106 patients with a monofocal IOL. It was also tested in a subgroup of 38 patients who had bilateral implantation of a diffractive bifocal IOL. Contrast sensitivity was tested using the Vision Contrast Test System (VCTS). RESULTS: In patients with a best corrected visual acuity (BCVA) of 1.0 or better, the CS at all spatial frequencies (1.5 to 18 cycles/degree), both at distance and near, was slightly lower in the bifocal IOL group than in the monofocal group. Mean values were within the normal range. In patients with a BCVA of less than 1.0, the CS was lower and the difference between the bifocal and monofocal groups was less. In patients with bilateral bifocal IOLs, CS was better when tested bilaterally than when testing the better eye alone. Pupil size affected the results to a small degree. Contrast sensitivity appeared to improve over time after implantation of a diffractive bifocal IOL. CONCLUSIONS: In patients with cataract and no other eye pathology, the diffractive bifocal IOL with slightly reduce the CS at all spatial frequencies. In those with reduced visual acuity after cataract surgery, CS will be reduced accordingly. In this situation, the reduction from the diffractive bifocal optic would be minor.

[The spiral CT of orbital space-occupying lesions: improved imaging possibilities via freely reconstructible planes]. / Spiral-CT von orbitalen Raumforderungen: verbesserte Darstellungsmöglichkeiten durch frei rekonstruierbare Ebenen.

In a prospective study the value of spiral CT for the detection and differential diagnosis of intraorbital masses was investigated. Thirty patients with various orbital diseases were examined with transverse spiral computed tomography. After performing two contiguous 1 mm spiral CT scans, coronal, parasagittal, and other reconstructions were obtained. Compared with separately generated 2 mm slices, the 1 mm spiral CT images showed a slightly decreased signal-to-noise ratio, but due to the better spatial resolution, the image quality of secondary reconstructions was similar to that of the original transverse spiral CT slices. Generally the orbital masses were visualized best in the coronal reconstruction. In certain cases, the parasagittal reconstructions were superior. Reconstructions in freely definable slice planes based on 1 mm spirals provides better visualization of orbital diseases without increasing radiation dose. This method allows multiplanar reconstructions similar to magnetic resonance tomography.

[Dye laser coagulation of diabetic maculopathy]. / Farbstofflaserkoagulation der diabetischen Makulopathie.

Eighty eyes of 48 patients were followed after laser photocoagulation (615 nm) of the macula because of diabetic macular edema. The follow-up time was at least 6 months (average 10.2 months). The morphological status improved in more than 60% of eyes with focal edema but in only 40% of eyes with diffuse macula edema. Improvement of distance visual acuity was obtained in 35% of the eyes, mostly in those with good baseline acuity (greater than or equal to 0.7). The fraction with improved visual acuity decreased to 13% in eyes with a baseline acuity of 0.6 or less. Similar results were found for near visual acuity. The discrepancies between morphological and functional improvement are still unclear.

[Scar formation in the cornea after photorefractive keratectomy]. / Zur Narbenbildung der Hornhaut nach photorefraktiver Keratektomie.

The morphologic correlate of the so-called subepithelial haze after photorefraktive keratectomy (PRK) has not yet been decided. Excimer laser keratectomy 100 microns in depth was performed in an eye that was scheduled for enucleation. Three months after surgery a dense scar was diagnosed with the slit lamp. After enucleation the cornea was investigated by light microscopy. The thickness of the scar was less than 1 micron in most sections with a maximum of 5 microns. This surprising finding explains the predominantly scattering power of the subepithelial haze, which results in a relatively good visual acuity of 20/30 to 20/25 in most clinical cases.

[Analysis of photo-ablation products of excimer and erbium:YAG laser treated human corneas. Combined gas chromatography/mass spectroscopy]. / Analyse der Photoablationsprodukte von mit Excimer- und Erbium: YAG-Laser behandelten menschlichen Hornhäuten. Kombinierte Gaschromatographie/Massenspektroskopie.

The photoablation products from human cadaver corneas treated with an excimer laser (192 nm) or an erbium: YAG laser (2.94 microns) were qualitatively analyzed using a combined gas chromatography mass spectrometry (GC/MS) system. GC/MS is the most sensitive analyzing system in use today for molecules with a relative molecular mass of 40 to 400. More than 20 different types of molecules were detected; most of them were identified as alkanes. Comparison of the two types of laser showed larger fragments and fewer different types of molecules after excimer laser treatment than after erbium: YAG photoablation. We postulate that the smaller molecules after erbium: YAG treatment indicate a greater heat during photoablation than with excimer laser treatment.