Biomedical subjects

J Wollensak

Publications and source records attributed to J Wollensak.

At least 19 recordsLinked to original sources

PubMed1992

[Retinal detachment with posterior chamber lens].

Pseudophakic retinal detachment was seen in 55 cases out of 13,692 patients that underwent cataract surgery and posterior chamber lens implantation in a 5 year period. The six-month incidence was 0.4%. Main risk factors were: myopia, capsular tear resp. zonular dialysis, and male gender. Sulcus- and capsular bag fixation showed the same incidence. 42% of pseudophakic retinal detachments occurred within the first 12 months after cataract surgery and 84% within the first three years. The resulting cumulation rate is discussed. The outcome of detachment surgery was reduced with increased rate of PVR. No typical localisation of retinal holes was found.

Adult↗

PubMed1992

["No-stitch" cataract surgery as a routine procedure. Technique and experiences].

We present a modified self-sealing wound construction with a trapezoidal incision for No-Stitch-Technique. Due to the form of the incision and the elasticity of the sclera the 6 mm incision can be extended to about 8 mm which allows an implantation of conventional PMMA-IOL without excessive scleral stretching. Since the beginning of 1991 this technique has been used routinely in our clinic with over 1500 operations. The No-Stitch-Technique has, in comparison to the sutured corneo scleral incision, two main advantages: the wound closure has a five fold higher stability and an induced astigmatism of less than 1.0 dpt. Other postoperative complications, such as wound dehiscence, iris prolapse and hypotony syndrome, were significantly eliminated.

Astigmatism↗

PubMed1992

[Complications of laser keratomileusis with the excimer laser (193 nm)].

Complications of photorefractive keratectomy (PRK) for myopia correction are presented based on 615 procedures with a follow-up of up to 2 years. Intraoperative complications with experienced surgeons are extremely rare. The used laser system worked without technical failures for the last 18 months. Gross eccentricities of the ablative zone (1.0 mm to 1.5 mm) occurred in two eyes (0.3%). Also, epithelial disorders are very rare. Recurrent erosions did not occur. Increased intraocular pressure due to the postoperative steroid medication (dexamethasone 0.1% or prednisolone 1%) was manifest in about 30% in patients with a baseline myopia of up to -9.0 D. In myopia over -9.0 D the incidence of steroid glaucoma was about 50%. Steroid responders reveal an increased risk of overcorrection. Subepithelial haze is a common symptom after PRK. Scarring interfering with vision correlates with the amount of attempted correction: up to 6.0 D the incidence of scars is about 0.5% and increases to more than 10% in corrections of more than 10 D. Also, undercorrections of more than 1 D depend strongly on the attempted correction. The most severe complication was a noninfectious corneal ulcer in a patient with systemic lupus erythematosus. Therefore, autoimmune and connective-tissue diseases represent an absolute contraindication for PRK. Corrections of more than 6.0 to 7.0 D should be considered as a relative contraindication for PRK at this time.

Adult↗

PubMed1992

[Christmas tree ornament cataract--an indication for disordered lipid metabolism?].

Cataract combined with Christmas tree decoration crystals in the lens is a relatively rare but very impressing cataract formation. The aim of this controlled study was to give an answer to the question, whether cholesterol level in blood is as important for local cholesterol accumulation in the lens as it is for the mechanism of arteriosclerosis. The blood levels of cholesterol, triglyceride, HDL and LDL were examined in 35 patients (average age 83.5 years; 26 women, 9 men). There was no significant difference between these parameters and those of a control group, which is similar in age and sex proportion. Therefore it is presumed, that these crystals of cholesterol are a result of lens metabolism and not of hypercholesterolemia.

Aged↗

PubMed1992

[Biometric data of eyes after the onset of acute glaucoma].

Biometric measurements were performed in 67 patients after acute glaucoma and in 67 patients of a matched control group. For patients with acute glaucoma the subjective refraction was +0.91 +/- 2.82 dpt, ocular axial length was 21.73 +/- 0.96 mm, lens thickness was 4.95 +/- 0.63 mm and the ratio lens thickness to ocular axial length amounted to 2.27 +/- 0.29. There was a statistically significant difference between the glaucoma and the control group concerning the parameters subjective refraction, ocular axial length, lens thickness and the lens thickness to axial length ratio. A statistically significant positive correlation was found between corneal radius and axial length, both, in the control and the glaucoma group, a significant negative correlation between axial length and subjective refraction only in the control group. In contrast to other authors, who reported on patients with narrow angle glaucoma with and without acute attack; we found no significant difference. These results support the suggestion that biometric data do not allow a prediction whether a patient with narrow anterior chamber angle will suffer glaucoma attack or not. The etiology of this disease seems to have a multifactorial origin.

Acute Disease↗

PubMed1992

[Intraoperative complications in cataract surgery. A prospective study].

In a prospective study the important intraoperative complications encountered by two experienced and eight less experienced surgeons after 1708 cataract operations were analyzed. In 2.3% a lesion of the iris or iris sphincter occurred. The overall incidence of capsular ruptures was 0.94%. Zonular dialysis was found in 0.67%. If a severe intraoperative complication with a large capsular or zonular rupture is defined by the necessity for an anterior vitrectomy or the impossibility of implanting a standard posterior chamber lens, the rate of complications was about 0.4%. For the two experienced surgeons, only two anterior chamber lenses as stand-by lens were implanted out of 1500 operations.

Cataract Extraction↗

PubMed1992

[Early postoperative corneal astigmatism. Comparison of various suture techniques].

We compared two suture techniques after phacoemulsification and implantation of a standard PMMA posterior chamber lens with a 7 mm intrascleral lamellar incision: the cross-stitch (double running) suture closure and the one-stitch technique. Two series with 100 patients each were examined. In the early postoperative period the astigmatism induced was 1.9 +/- 1.4 D in the cross-stitch group and 1.5 +/- 1.0 in the one-stitch group (P = 0.01). In the latter group, 20% more of the patients were found to have a moderate amount of astigmatism. Four weeks after surgery, however, there were no differences between the two groups. The induced astigmatism in both groups was 1.0 D.

Astigmatism↗

PubMed1992

[Space-occupying lesions of the orbit: modern imaging diagnosis].

The paper summarises imaging of orbital diseases by CT and MRI. As localisation is an important clue to differential diagnosis in orbital tumours, the different pathologies are described according to sites of prevalent occurrence. Morphological criteria of orbital pathology are described, and the more frequent entities are illustrated.

Diagnosis, Differential↗

PubMed1992

Diurnal variation in refraction after excimer laser photorefractive keratectomy.

Diurnal fluctuations in vision are common after radial keratotomy (RK), associated with a myopic change in refraction and keratometric power mostly in the morning. After photorefractive keratectomy (PRK), only a small percentage of patients report fluctuations of vision. We tested ten such patients who had undergone excimer laser PRK with regard to refraction, keratometry, and visual acuity 5 to 20 months after surgery. Patients were examined five times during one day from 8:00 a.m. to 8:00 p.m. Ten volunteers serving as a control group were examined following the same protocol. None of the patients showed an increase in minus spherical power of the manifest refraction between morning and evening. The change in manifest refraction from morning to evening was +0.3 D +/- 0.3 D, which was not significantly different from the control group. The change in refraction did not correlate with keratometric power, follow-up time of age of the patients.

Adult↗

PubMed1992

Pseudoexfoliation syndrome and glaucoma. Does glaucoma capsulare exist?

Pseudoexfoliation syndrome (PES) is seen in patients with a characteristic deposition of material on the anterior preequatorial region of the lens and on a variety of surfaces throughout the anterior segments of the eye. A high frequency of associated glaucoma has also been reported. In spite of numerous clinical and histological investigations, the mechanisms for the glaucoma are unclear. In a series of 5154 patients referred to our hospital for cataract extraction we found a prevalence of 6.1% (n = 314). In 51 of these patients (16.2%) glaucoma was diagnosed in contrast to 33 patients (10.9%) in an age-matched control group. The prevalence of glaucoma in PES patients and the control group was not statistically different, so our findings in cataract patients do not support the interpretation that there is a clinical entity called "glaucoma capsulare."

Aged↗

PubMed1992

[Analysis of photo-ablation products of excimer and erbium:YAG laser treated human corneas. Combined gas chromatography/mass spectroscopy].

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.

Alkanes↗

PubMed1992

Pterygium excision using 193-nm excimer laser smoothing and topical mitomycin C.

A total of 31 eyes with primary pterygium and 24 eyes with recurrent pterygium underwent surgical treatment and were followed for at least 1 year. The surgery involved a conventional bare-sclera technique combined with excimer laser smoothing of the wound bed. Postoperatively, the eyes were medically treated with topical mitomycin C (0.02%) for 4 days and with steroids for several weeks. No recurrence was noted within the 1st year in the primary pterygium group, whereas recurrence was observed in 3/24 eyes that had been treated for recurrent pterygium, equivalent to a recurrence rate of 12.5% in this subgroup. Nine eyes (16.4%) had gained 2 lines or more in visual acuity by 1 year after surgery. Granuloma developed in 3 eyes, and dellen formation was detected in 1 eye after surgery. The combination of surgical management with local mitomycin therapy may be considered to be a safe and effective technique for the removal of pterygium. Although the visual results were good, the role of excimer laser smoothing in the treatment of this disorder needs further investigation.

Female↗

PubMed1992

[Dye laser coagulation of diabetic maculopathy].

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.

Adult↗

PubMed1992

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.

Cornea↗

PubMed1991

[Refractive surgery of the cornea. Corneal surgery--an alternative to optical aids?].

Errors of refraction of the eye can be corrected not only by means of spectacles, contact lenses or intra-ocular lenses, but also by operative procedures on the cornea. At present, correction of myopia is accomplished with radial keratotomy (RK), a procedure that achieves the best results in the range up to - 6.0 diopters. However, on account of its side effects, in particular poor predictability, the method is no true alternative to the use of optical aids. Epikeratoplasty done to correct hyperopia and aphakia, is even more imprecise, and should only be employed in exceptional cases. Laser surgery of the cornea is still undergoing clinical testing, but has already produced promising results.

Astigmatism↗

PubMed1991

Myopic photorefractive keratectomy with the excimer laser. One-year follow-up.

To evaluate the efficacy, predictability, and stability of myopic photorefractive keratectomy (PRK), the authors completed a 1-year follow-up study on a consecutive series of 26 sighted eyes undergoing this procedure. The results of this follow-up are presented. In addition, side effects and complications in another 255 sighted eyes with a follow-up of 3 months to 1 year are reported to judge the safety of the procedure. Twenty-four of 26 eyes (92%) were within +/- 1.0 diopter (D) of the intended final refraction (baseline, -1.4 to -9.25 D). Fifty-eight percent of the eyes were stable within +/- 0.25 D between 6 and 12 months. One year after surgery, none of the patients lost or gained more than one line of best corrected (spectacle) visual acuity. Uncorrected visual acuity improved to 20/40 or better in 96% of the eyes and to 20/20 or better in 48% of the eyes (not including the eyes that were intentionally undercorrected). However, visual acuity with glare decreased from 20/27 preoperatively to 20/31 after 1 year. Scarring occurred in 2.8% of the treated corneas. Risk factors for scarring include noncompliance with postoperative steroid medication, high myopic corrections, and high steroid responders (3.1%). Collagen vascular and other autoimmune diseases are a contraindication for PRK.

Adult↗

PubMed1991

[Implantation of folding posterior chamber lenses].

The implantation of foldable intraocular lenses (IOL) takes advantages of the benefit of small incision cataract surgery provided by phacoemulsification. However, even experienced surgeons may find the new implantation techniques required initially difficult. Advantages of small incision techniques include maintaining stability of the globe during surgery, especially in the case of acute IOP elevation caused by choroidal effusion or expulsive hemorrhage, as well as improved postoperative healing. Small incision surgery minimizes induced astigmatism, to less than 1.0 dpt change. Therefore, the patients physical and visual rehabilitation can be accelerated. Soft IOL's composed of p-HEMA or Silicone materials have been investigated for the past ten years and appear to be well biocompatible. The p-HEMA lens most often implanted is the IO-GEL, manufactured by Alcon. 120 p-HEMA IOL's were implanted in our clinic over the past 2 years. Our experiences with this foldable IOL are reported.

Foreign-Body Reaction↗

PubMed1991

[Clinical results after implantation of a multifocal diffractive posterior chamber lens].

45 diffractive multifocal posterior chamber lenses were implanted in 41 patients. The follow-up time amounted to 12 months. With one correction good visual acuity for far and as well as near distances could be achieved. A significant loss of visual acuity with glare and low contrast and of contrast sensitivity was observed. Future has to show whether the advantages of this multifocal PCL will equal the disadvantages to the modern standard PMMA-PCL.

Follow-Up Studies↗