Jørgen Krohn

Iris cyst associated with topical administration of latanoprost

PURPOSE To report an adverse side effect associated with topical latanoprost usage. METHOD Case report. A 76-year-old woman with primary open-angle glaucoma developed an iris cyst 5 weeks after beginning treatment with latanoprost. Clinical examinations and slit-lamp photographs were performed. RESULTS Latanoprost was discontinued. Periodic examinations disclosed that the iris cyst gradually diminished and finally disappeared within 3 weeks. CONCLUSION The formation of an iris cyst is a possible complication of topical latanoprost therapy.

Dosimetric verification of a dedicated 3D treatment planning system for episcleral plaque therapy

PURPOSE Episcleral plaque therapy (EPT) is applied in the management of some malignant ocular tumors. A customized configuration of typically 4 to 20 radioactive seeds is fixed in a gold plaque, and the plaque is sutured to the scleral surface corresponding to the basis of the intraocular tumor, allowing for a localized radiation dose delivery to the tumor. Minimum target doses as high as 100 Gy are directed at malignant tumor sites close to critical normal tissues (e.g., optic disc and macula). Precise dosimetry is therefore fundamental for judging both the risk for normal tissue toxicity and tumor dose prescription. This paper describes the dosimetric verification of a commercially available dedicated treatment planning system (TPS) for EPT when realistic multiple-seed configurations are applied. MATERIALS AND METHODS The TPS Bebig Plaque Simulator is used to plan EPT at our institution. Relative dose distributions in a water phantom, including central axis depth dose and off-axis dose profiles for three different plaques, the University of Southern California (USC) #9 and the Collaborative Ocular Melanoma Study (COMS) 12-mm and 20-mm plaques, were measured with a diode detector. Each plaque was arranged with realistic multiple 125I seed configurations. The measured dose distributions were compared to the corresponding dose profiles calculated with the TPS. All measurements were corrected for the angular sensitivity variation of the diode. RESULTS Single-seed dose distributions measured with our dosimetry setup agreed with previously published data within 3%. For the three multiple-seed plaque configurations, the measured and calculated dose distributions were in good agreement. For the central axis depth doses, the agreement was within 4%, whereas deviations up to 11% were observed in single points far off-axis. CONCLUSIONS The Bebig Plaque Simulator is a reliable TPS for calculating relative dose distributions around realistic multiple 125I seed configurations in EPT.

Posterior uveal melanoma treated with I-125 brachytherapy or primary enucleation

PurposeTo study the incidence, clinical findings, and tumour characteristics of posterior uveal melanoma in Western Norway, and to report the results of a consistent treatment strategy (I-125 brachytherapy or primary enucleation) over a 13-year period.MethodsThe clinical records of all patients with posterior uveal melanoma referred between January 1993 and December 2005 were reviewed. Clinical data, radiation parameters, visual outcome, and mortality were analysed in a dedicated database.ResultsThe study included 111 consecutive patients. The annual age-adjusted incidence (per million population) of posterior uveal melanoma was 8.5 for women and 8.9 for men. Fifty-six patients underwent I-125 brachytherapy, 52 were enucleated, and three received no treatment. The median follow-up time was 36 months (mean, 52 months; range, 2 months to 13 years). In the brachytherapy group, two eyes were enucleated owing to tumour recurrence and two because of neovascular glaucoma. A visual acuity of 0.1 or better, present in 87% of the patients before brachytherapy, was retained in 40% after a median follow-up of 61 months. After brachytherapy, the 5- and 10-year melanoma-specific mortality rates were 13.4 and 23.8%, respectively. The corresponding mortality rates for patients treated with primary enucleation were 49.5 and 49.5%.ConclusionAfter brachytherapy, many patients lost useful vision due to radiation-induced complications. The probability of retaining the eye was high and only two patients experienced recurrent tumour growth. The mortality rates compare well with published series, and the differences in tumour size explain the difference in mortality between the two treatment groups.

Retrobulbar anesthesia with and without hyaluronidase in extracapsular cataract surgery

Abstract. Eighty patients with senile cataract were subjected to a planned extracapsular cataract extraction (ECCE) with implantation of a posterior chamber intraocular lens. Retrobulbar anesthesia was administered by injection of 4 mg lidocaine 2% with adrenalin. In 40 patients 150 I.U. hyaluronidase (Kinetin®) was added to the anesthesia. The hyaluronidase group had a significantly lower frequency of iris prolapse, and deeper anterior chamber, both before and after expression of the lens nucleus. Possible mechanisms explaining the beneficial effect of hyaluronidase in extracapsular cataract surgery are discussed.

Short‐term postoperative non‐supine positioning versus strict face‐down positioning in macular hole surgery

Purpose:  The purpose of this study was to compare the efficacy of short‐term non‐supine positioning (NSP) and strict face‐down positioning (FDP) in the repair of macular hole (MH).

Photopic full-field electroretinography and optical coherence tomography in type 1 diabetic retinopathy

PurposeThe purpose of this study was to evaluate the role of photopic full-field electroretinography (ERG) and retinal thickness measurements by spectral-domain optical coherence tomography (SD-OCT) in the assessment of disease severity in type 1 diabetic retinopathy.MethodsA population-based cohort of 151 patients with type 1 diabetes underwent a complete ophthalmic examination, including photopic full-field ERG and SD-OCT for retinal thickness measurements. Stereoscopic fundus photographs were taken according to the Early Treatment Diabetic Retinopathy Study protocol, and the classification of diabetic retinopathy was based on the International Clinical Diabetic Retinopathy Disease Severity Scale. Associations between photographically determined retinopathy level, b-wave amplitude and peak time of the photopic single-flash and 30-Hz flicker ERG, and central retinal thickness parameters were evaluated.ResultsFor all ERG measurements, the amplitude decreased and peak time increased with progression of the disease, but these associations lost statistical significance after adjusting for age and excluding laser-treated patients. Mean retinal thickness was significantly associated with the b-wave amplitude of photopic single-flash and 30-Hz flicker responses (r2 = 0.08, p = 0.006; and r2 = 0.05, p = 0.025, respectively), but revealed no association with retinopathy level.ConclusionsPhotopic full-field ERG and SD-OCT-derived retinal thickness parameters have limited clinical value in the staging of diabetic retinopathy. However, thinning of the central retina leads to significant functional impairment and may reflect an ongoing neurodegenerative process in the retinal tissue.

Switching from pro re nata to treat‐and‐extend regimen improves visual acuity in patients with neovascular age‐related macular degeneration

To evaluate the visual outcome after transitioning from a pro re nata (PRN) intravitreal injection regimen to a treat‐and‐extend (TAE) regimen for patients with neovascular age‐related macular degeneration (AMD).

Small fibre neuropathy in Fabry disease

Fabry disease is an X-linked inherited lysosomal storage disorder associated with glycosphingolipid accumulation in organs and vascular endothelium [1]. Neuropathic pain is common in Fabry disease and is associated with small fibre neuropathy [2, 3]. The diagnosis of small fibre neuropathy is based on symptoms like paresthesias, dysesthesias and pain and clinical signs with abnormal pin prick sensation, quantitative sensory testing (QST) and skin biopsy [4]. Corneal confocal microscopy examination of patients with diabetes mellitus as well as Fabry disease has demonstrated a reduction in sub-basal nerve density, also reflecting small fibre neuropathy [5–7]. In the present study we have compared these tests in patients with Fabry disease. Fifteen patients (five males with mean age of 16.2 years and 10 females with mean age of 33.8 years) with Fabry disease, all verified by mutation analysis, were recruited from the Bergen Fabry cohort at Haukeland University Hospital, Bergen, Norway (2004–2009). Blood levels of alpha-galactosidase varied from 2.2 to 37.8 lkat/kg protein (N: 17.7–26.4). All patients had episodes of neuropathic pain aggravated by heat. Eleven sexand age-matched healthy individuals served as controls for the assessment of small fibre affection. The disease severity scoring system (DS3) was used to measure the general neurological, cardiovascular and renal symptoms and signs in the Fabry patients [8]. Age was positively correlated with the DS3 total score (r = 0.68, p = 0.005; Pearson’s test), while it was negatively associated with the DS3 peripheral nervous system (PNS) score (r = -0.52, p = 0.045; Pearson’s test). Males had higher DS3 PNS score than females (p = 0.043; t test), but there was no sex association with DS3 total score (p = 0.73; t test). The alpha-galactosidase levels were not associated with the DS3 PNS score (r = 0.40, p = 0.135; Pearson’s test). Routine clinical and neurological examination, nerve conduction studies, electromyography, and QST (vibrametry and thermotests) were performed. A slit scanning confocal microscope (Confoscan 3, Nidek Technologies, Vigonza, Italy) was used to measure the sub-basal cornea nerve fibre length (CNFL) (mm/mm) in the central cornea of one eye of each subject. Skin-punch biopsy from the A. K. Bertelsen J. Aarseth C. A. Vedeler (&) Department of Neurology, Haukeland University Hospital, Bergen, Norway e-mail: christian.vedeler@helse-bergen.no

Early panretinal photocoagulation for ERG‐verified ischaemic central retinal vein occlusion

Purpose:  We have previously shown that photopic cone b‐wave implicit time ≥35.0 ms in 30 Hz flicker electroretinography (ERG) predicts ocular neovascularization (NV) in central retinal vein occlusion (CRVO). Here, we evaluate the effects of early panretinal photocoagulation (PRP) in patients with ERG‐verified ischaemic CRVO.

Effects of static accommodation versus repeated accommodation on intraocular pressure.

PurposeTo compare the influences of static and repeated accommodation on the intraocular pressure (IOP). Materials and MethodsA randomized, single-blind study was carried out on 33 healthy volunteers aged 20 to 29 years. Baseline IOP was measured after 10 minutes of viewing a distant target. Static accommodation was achieved by letting the volunteers focus for 3 minutes on a near target, which was individually adjusted to induce a 3 D accommodative demand. For the repeated accommodation, the volunteers were instructed to alternately focus on the near and distant target for 3 minutes. The accommodative responses were continuously monitored by an infrared photorefractor (PowerRef II), and Goldmann tonometry was performed immediately after the accommodative procedures. ResultsThe IOP values (mean±SD) measured after static and repeated accommodation were 13.4±2.4 mm Hg and 12.7±2.3 mm Hg, respectively (P=0.04). The IOP decreased significantly from baseline after both the static and repeated mode of accommodation with a mean change of −1.76±1.17 mm Hg (range, 0 to 4 mm Hg) and −2.06±1.48 mm Hg (range, 0 to 5 mm Hg), respectively. The IOP drop seemed to be greater after repeated accommodation compared with static accommodation; however, the difference was not statistically significant (P=0.35). ConclusionsThe IOP was significantly reduced after both static and repeated accommodation. Compared with static accommodation, the repetitive mode of accommodation did not induce a statistically significant additional IOP drop, indicating that aqueous humor outflow is relatively unaffected by frequent ciliary muscle contractions.