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Biomedical subjects

M W Ulbig

Publications and source records attributed to M W Ulbig.

At least 37 records · Page 2Linked to original sources
PubMed2000

Central corneal thickness determined with optical coherence tomography in various types of glaucoma.

AIMS: To evaluate central corneal thickness determined by optical coherence tomography (OCT) in various types of glaucoma, and its influence on intraocular pressure (IOP) measurement. METHODS: Central corneal thickness (CCT) was determined by using OCT in 167 subjects (167 eyes). 20 had primary open angle glaucoma (POAG), 42 had low tension glaucoma (LTG), 22 had ocular hypertension (OHT), 10 had primary angle closure glaucoma (AC), 24 had pseudoexfoliation glaucoma (PEX), 13 had pigmentary glaucoma (PIG), and 36 were normal. RESULTS: CCT was significantly higher in ocular hypertensive subjects (593 (SD 35) microm, p <0.0001) than in the controls (530 (32) microm), whereas patients with LTG (482 (28) microm, p < 0. 0001), PEX (493 (33) microm, p <0.0001), and POAG (512 (30) microm, p <0.05) showed significantly lower readings. There was no statistically significant difference between the controls and patients with PIG (510 (39) microm) and AC (539 (37) microm). CONCLUSIONS: Because of thinner CCT in patients with LTG, PEX, and POAG this may result in underestimation of IOP, whereas thicker corneas may lead to an overestimation of IOP in subjects with OH. By determining CCT with OCT, a new and precise technique to measure CCT, this study emphasises the need for a combined measurement of IOP and CCT in order to obtain exact IOP readings.

Aged↗
PubMed2000

Resolution of diabetic macular edema after surgical removal of the posterior hyaloid and the inner limiting membrane.

PURPOSE: To evaluate the surgical results of pars plana vitrectomy with peeling of the inner limiting membrane (ILM) in a preliminary series of 12 eyes with diffuse diabetic macular edema. PATIENTS AND METHODS: Pars plana vitrectomy with peeling of the ILM was performed in 12 eyes with diffuse diabetic macular edema. In 10 eyes, the posterior hyaloid was attached and thickened. Six eyes had undergone macular photocoagulation previously, and two other eyes had been vitrectomized previously. Light and electron microscopy of the specimens obtained during vitrectomy was performed. Visual acuity and retinal thickening were monitored. RESULTS: Intraoperatively, the posterior hyaloid was found to be thickened and completely attached to the macula in 10 eyes. Two previously vitrectomized eyes showed a glistening reflex of the vitreoretinal interface but no premacular membrane. The posterior hyaloid and the ILM were removed from the macula. Postoperatively, retinal thickening resolved or decreased in all eyes. Visual acuity improved by at least two lines in 11 eyes. Best-corrected postoperative visual acuity developed within 4 to 12 weeks. No recurrence or deterioration of macular edema or epiretinal membrane formation were observed during the entire period of review (mean, 16 months; range, 8-31 months). Light and electron microscopy showed the presence of the ILM associated with sparse and mostly single-layered fibrous astrocytes. CONCLUSION: Vitrectomy including removal of the ILM leads to expedited resolution of diffuse diabetic macular edema and improvement of visual acuity without subsequent epiretinal membrane formation. Complete release of tractional forces and inhibition of reproliferation of fibrous astrocytes seem to be prudent in the eyes of patients with diabetes and advanced vitreoretinal interface disease of the macula.

Adult↗
PubMed1998

Long-term results after drainage of premacular subhyaloid hemorrhage into the vitreous with a pulsed Nd:YAG laser.

OBJECTIVE: To investigate the effects of drainage of premacular subhyaloid hemorrhage into the vitreous with an Nd:YAG laser in a large series of patients with long-term follow-up. METHODS: A retrospective review was conducted on 21 eyes with a circumscribed premacular subhyaloid hemorrhage of various causes. These eyes were treated with a pulsed Nd:YAG laser to drain the entrapped blood into the vitreous. The period of review ranged from 12 to 32 months (mean, 22 months). RESULTS: In 16 eyes, visual acuity improved within 1 month. Four eyes had persistent, dense, nonclearing vitreous opacity for at least 3 months and finally required vitrectomy. One clotted hemorrhage did not drain into the vitreous. Final visual outcome was determined by the underlying diagnosis, such as Valsalva retinopathy (7 eyes), diabetic retinopathy (7 eyes), branch retinal vein occlusion (4 eyes), and retinal macroaneurysm, Terson syndrome, or blood dyscrasia (1 eye each). Eyes with Valsalva retinopathy fared the best. Complications included a macular hole in 1 eye and a retinal detachment from a retinal break in a myopic patient. CONCLUSIONS: Drainage of premacular subhyaloid hemorrhage into the vitreous with an Nd:YAG laser is a viable treatment alternative for eyes with recent bleeding. However, a macular hole and a retinal detachment were observed as complications. Thus, to establish Nd:YAG laser treatment as a routine procedure, the risks and benefits have to be weighed in a randomized trial and compared with those of deferral of treatment or primary vitrectomy.

Adult↗
PubMed1998

[North Carolina macular dystrophy. Hereditary macular disease with good functional prognosis].

BACKGROUND: North Carolina macular dystrophy (NCMD) is a rare autosomal dominant maculopathy with highly variable expressivity. Genetic analysis of an American family consisting of 247 members out of which 96 were affected with NCMD allowed chromosomal assignment of the NCMD locus to 6q14-q16.2. Few families with NCMD are known in Europe, one of these is living in Germany. By routine investigation, a second family affected with NCMD was detected in Germany. As some authors still doubt the good prognosis of this disease, our results should be added to the experience of others. PATIENTS AND METHODS: In a total of 18 family members from three generations between the age of 2 and 65 years, clinical investigations and genetic analysis was carried out. Some individuals had additional examinations such as colour contrast sensitivity, EOG, ERG, and microperimetry. RESULTS: Ten of 18 family members turned out to be affected. All grades of NCMD were present with great variability. Visual acuity ranged from 0.32 to 1.0 and did not correlate to the grade of the disease or to the age of the person. In those patients who underwent microperimetry, central fixation was confirmed. Genetic linkage analysis further narrowed the region harbouring the NCMD locus and supported the assumption that the central areolar pigment epithelial dystrophy (CAPED) is an allelic disorder. CONCLUSION: Similar visual acuity in three generations of NCMD patients supports the observation that NCMD is not a progressive disorder. If geographic atrophy is found in a patient with good visual acuity, NCMD should be considered and genetic analysis should be carried out.

Adolescent↗
PubMed1995

[Risk factors for surgical failures in rhegmatogenous retinal detachment].

BACKGROUND: The evaluation of further risc factors predesposing failure in retinal detachment surgery than those already known to be associated with PVR was the goal of this retrospective study. PATIENTS AND METHODS: The data from 130 cases with unilateral rhegmatogenous retinal detachment treated initially with buckling procedures, were retrospectively reviewed to investigate pre-, intra- and postoperative factors which may predispose anatomical failure in retinal detachment surgery. None of the selected consecutively operated eyes had risk factors, which have already been associated with an unfavourable outcome, such as the presence of preoperative macular holes, PVR or assumed PVR-inducing factors, such as ocular trauma, giant retinal tears, vitreous hemorrhage, previous vitrectomy, cryopexy and laser photocoagulation. RESULTS: The anatomic success rate after scleral buckling procedures was 78.5% and the overall success rate after multiple surgery including vitrectomy increased to 94.6%. 102 (78.5%) cases, treated with a maximum of two scleral buclking operations were statistically compared to the 28 cases which needed further vitreoretinal surgery. The statistical analysis revealed as preoperative risk factors for failure in rhegmatogenous retinal detachment surgery 1) retinal detachment exceeding two retinal quadrants (p < 0.05) and 2) size of the retinal tear larger than 60 degrees (p < 0.05), whereas postoperative risk factors were 1) presence of subretinal hemorrhage (p < 0.01) and 2) persistent subretinal fluid at least two days after surgery (p < 0.01). Eyes with preoperative visual acuity less than 0.1, pseudophacic eyes with posterior chamber intraocular lenses and eyes with severe intraoperative hypotony also showed a tendency to unfavourable outcome, but without a statistically significant level. CONCLUSIONS: Possible ways of interfering in the retinal reattachment process and the clinical importance of these evaluated factors are discussed. They should be taken in consideration for the prognosis of the postoperative anatomical result and treatment modalities if further surgery is required.

Adult↗
PubMed1995

Diode laser photocoagulation for diabetic macular oedema.

AIMS: This study aimed to investigate whether diode laser irradiation, which is poorly absorbed by haemoglobin, can induce closure of leaking retinal microvascular lesions in the treatment of diabetic macular oedema. METHODS: Thirty three eyes with clinically significant diabetic macular oedema were treated with a diode laser. Fundus evaluation before and after treatment included visual acuity, stereoscopic biomicroscopy, colour photographs, and fluorescein angiography. RESULTS: At a mean period of review of 6 months macular oedema had completely or partially resolved in 27 eyes. Visual acuity improved in three, deteriorated in one, and was unchanged in 29 eyes. CONCLUSION: Preliminary data suggest that diode laser therapy induces closure of leaking retinal microaneurysms and is effective in the treatment of diabetic macular oedema.

Adult↗
PubMed1995

Clinical comparison of semiconductor diode versus neodymium: YAG non-contact cyclo photocoagulation.

AIMS: The advent of diode lasers has allowed their use in transscleral cyclo photocoagulation for refractory glaucoma. A trial was performed to compare the ocular hypotensive and inflammatory effects of cyclo photocoagulation using a continuous wave diode (810 nm) and a free running neodymium:yttrium aluminium garnet (Nd:YAG) laser (1064 nm). METHODS: Forty patients with refractory glaucoma were randomised to receive either diode or Nd:YAG therapy. The intraocular pressure (IOP) and inflammatory response to treatment were monitored over 3 months. RESULTS: There was no significant laser related difference in the effect on IOP after one treatment. There was, however, a difference in effect in retreatments with the IOP lowering effect significantly less, but equally sustained in diode retreatment patients. Severe postoperative complications such as hyphaema or fibrinous anterior uveitis only occurred in the Nd:YAG group. CONCLUSION: The degree and duration of the ocular hypotensive response to cyclo photocoagulation appears to be related to the available power output of the system used, and the extent of tissue damage.

Adult↗
PubMed1995

Insulin-like growth factor I (IGF-I) receptor/binding protein in human diabetic epiretinal membranes.

Insulin-like growth factor I (IGF-I) is thought to play a role in the development of proliferative diabetic retinopathy. Proliferative diabetic retinopathy is characterised by the formation of fibrovascular epiretinal membranes, and IGF-I may initiate and/or potentiate this epiretinal proliferation. To evaluate further the part played by IGF-I in the development of epiretinal tissue, we investigated the presence of IGF-I receptor/binding protein in proliferating diabetic fibrovascular epiretinal membranes. Five fibrovascular epiretinal membranes were obtained by vitrectomy from five patients with proliferating diabetic retinopathy. The presence of IGF-I receptors was investigated by autoradiography using 125I-labeled IGF-I on frozen sections. To characterise binding specificity, some sections were preincubated with either insulin or unlabeled IGF-I. Sections of post-mortem liver were used as controls. Strong labeling of cells with 125I-labeled IGF-I was observed in all epiretinal membranes and in liver cells. Almost no autoradiographic labeling was observed in sections that had been blocked with non-radioactive IGF-I, and very little labeling was found following blockage with insulin. Our preliminary study suggests the presence of IGF-I receptor/binding protein in human diabetic epiretinal membranes. These results support the hypothesis that IGF-I may be involved in the formation of proliferative diabetic membranes.

Autoradiography↗
PubMed1994

Contact diode laser cyclo-photocoagulation for refractory glaucoma. A pilot study.

Initial experience with non-contact diode cyclo-photocoagulation for refractory glaucoma has shown positive results. Diode laser irradiation applied via a contact probe results in greater transmission through the sclera and delivery of more energy to the ciliary body. A trial was performed to evaluate the effects of contact diode cyclo-photocoagulation. A total of 12 patients with glaucoma due to conditions such as central retinal vein occlusion were treated. A mean of 22 pulses (810 nm) with powers of up to 2 W and of 2 s duration were applied via a fibre-optic delivery system and a contact probe. The mean intra-ocular pressure dropped from 42.3 to 13.6 mmHg over 3 months. Four patients required retreatment. Three patients had side effects that included hyphaema, anterior fibrinous uveitis and pupil block. In conclusion, contact diode cyclo-photocoagulation had a significant ocular hypotensive action in the treatment of refractory glaucoma. As compared with non-contact diode cyclo-photocoagulation, the contact modality produced more marked non-therapeutic side effects.

Adult↗
PubMed1994

[Iris neovascularization, increased intraocular pressure and vitreous hemorrhage as risk factors for invasion of the optic nerve and choroid in children with retinoblastoma].

A review of 289 eyes enculeated for retinoblastoma to evaluate prognostic factors for involvement of the choroid or optic nerve revealed choroidal invasion in 67 eyes (22%) and optic nerve invasion in 84 eyes (27%) due to retinoblastoma. Intraocular pressure (IOP) > or = 22 mmHg was found in 85 eyes prior to enucleation. A total of 118 eyes (38% showed histopathologic evidence of the development of glaucoma: 90 of them with iris neovascularisation and 28 with angle closure configuration. Patients with elevated IOP, iris neovascularisation and angle closure configuration had a significantly higher risk of optic nerve (P < 0.005) and choroidal (P < 0.002) involvement. On the other hand, optic nerve invasion due to retinoblastoma was significantly more frequent in eyes with elevated IOP (P < 0.02) and iris neovascularisation or angle closure configuration (P < 0.01). Risk factors for choroidal invasion of retinoblastoma were raised IOP (P < 0.04) and iris neovascularisations or angle closure configuration (P < 0.01) (univariant analysis). Raised IOP, iris neovascularisations and vitreous haemorrhage remained significant in the multivariant analysis. This study emphases the importance of IOP, iris neovascularisation and angle closure configuration as risk factors for outspreading invasion due to retinoblastoma.

Adolescent↗
PubMed1994

Long-term results of ab externo neodymium:YAG cyclophotocoagulation.

Neodymium: YAG cyclophotocoagulation (CPC) was performed in 128 eyes of 123 patients with refractory glaucoma. In each eye, 40 burns delivered with energy of up to 7 J were placed 1.5 mm behind the limbus in a 360 degrees pattern. The minimal follow-up period was 24 months, with the mean being 36.9 (range, 24-84; SD, 5.8) months. The mean intraocular pressure was 35.0 (range 23-54; SD, 12.2) mmHg preoperatively, 20.6 (range 15-24; SD, 3.5) mmHg after 1 year, and 20.2 (range 12-24; SD, 8.1) mmHg after 2 years. A total of 25 eyes (19.5%) lost 2 or more lines in visual acuity. Success was defined as a lowering of intraocular pressure by > 30% and a decrease in visual acuity of < 2 Snellen lines. By this definition the success rate was 52.4%. There was no correlation with either the diagnosis, the stage of the disease, or the pigmentation of the trabecular meshwork, although patients with secondary traumatic or uveitic glaucoma tended to be less responsive to CPC. The most common acute complication of treatment was transient corneal edema. Phthisis bulbi developed in 1 eye (0.8%). In conclusion, CPC achieved satisfactory long-term control of intraocular pressure in the majority of patients with severe late-stage glaucoma.

Adolescent↗
PubMed1993

Photocoagulation of choroidal neovascular membranes with a diode laser.

Nine eyes with parafoveal choroidal neovascular membranes due to age-related macular degeneration or angioid streaks were treated with a diode laser and were followed up to 40 weeks (mean 26 weeks). Angiographically proved closure of the membrane was achieved in seven eyes. Four lesions needed a second treatment for growth of subretinal neovascular tissue. Post-treatment visual acuity ranged from 6/9 to 6/60. Two eyes developed subfoveal membranes resulting in poor visual acuity. The morphology of the diode laser lesions differed from that of the argon green laser and was more similar to that of the krypton laser, producing a 'black hole' on the fluorescein positive print. In one particular eye fluorescein angiography revealed subfoveal choroidal non-perfusion next to the site of the diode lesion suggesting choroidal vascular closure.

Aged↗
PubMed1993

[Comparative use of diode and argon laser for panretinal photocoagulation in diabetic retinopathy].

The recently introduced semiconductor diode laser is portable, more compact, and cheaper to maintain than other laser systems. It is unclear whether its wavelength characteristics in the near infrared (810 nm) lead to different clinical results of retinal photocoagulation. In a prospective study ten diabetics (3 type I and 7 type II) ranging in age from 26 to 72 years with bilateral proliferative or severe nonproliferative diabetic retinopathy and visual acuity better than 6/18 in both eyes underwent panretinal photocoagulation. One eye was treated with the diode laser, the fellow eye with argon green (514 nm). Follow-up was documented by best-corrected visual acuity, fundus photography and fluorescein angiography. Mean duration of follow-up was 12 months. In neither group was there a significant difference in the response of retinopathy and neovascularization to the treatment, or in the course of visual acuity. Fluorescein angiography revealed the more profound effects of the diode laser in the choroid. Compared to argon laser treatment, patients found diode laser treatment more painful, but appreciated the absence of bright flashes during therapy. Photocoagulation for diabetic retinopathy using the diode laser was as effective as using the argon system in this initial pilot study.

Adult↗