Patient preferences for stratified medicine in psoriasis: a discrete choice experiment.

BACKGROUND: New technologies have enabled the potential for stratified medicine in psoriasis. It is important to understand patients' preferences to enable the informed introduction of stratified medicine, which is likely to involve a number of individual tests that could be collated into a prescribing algorithm for biological drug selection to be used in clinical practice. OBJECTIVES: To quantify patient preferences for an algorithm-based approach to prescribing biologics ('biologic calculator') in psoriasis. METHODS: An online survey comprising a discrete choice experiment (DCE) was conducted to elicit the preferences of two purposive samples of adults living with psoriasis in the UK, identified from a psoriasis patient organization (Psoriasis Association) and an online panel provider (Dynata). Respondents chose between two biologic calculators and conventional prescribing described using five attributes: treatment delay; positive predictive value; negative predictive value; risk of infection; and cost saving to the National Health Service. Each participant selected their preferred alternative from six hypothetical choice sets. Additional data, including sociodemographic characteristics, were collected. Choice data were analysed using conditional logit and fully correlated random parameters logit models. RESULTS: Data from 212 respondents (67 from the Psoriasis Association and 145 from Dynata) were analysed. The signs of all estimated coefficients were consistent with a priori expectations. Respondents had a strong preference for a high predictive accuracy and avoiding serious infection, but there was evidence of systematic differences in preferences between the samples. CONCLUSIONS: This study indicates that individuals with psoriasis would value a biologic calculator and suggested that such a biologic calculator should have sufficient accuracy to predict future response and risk of serious infection from the biologic.

Diurnal fluctuation of ocular blood flow parameters in patients with primary open-angle glaucoma and healthy subjects.

BACKGROUND/AIMS: To investigate the fluctuations of ocular blood flow parameters over 13 h in patients with primary open-angle glaucoma (POAG) and in healthy eyes, and to relate these fluctuations with variations in intraocular pressure (IOP) and mean ocular perfusion pressure (OPP). METHODS: 15 patients with POAG and 15 control subjects were included. Measurements of systemic blood pressure (SBP), fundus pulsation amplitude (FPA), choroidal blood flow (CHBF), optic nerve head blood flow (ONHBF) and IOP were performed at 08:00, 12:00, 17:00 and 21:00. OPP was calculated from IOP and SBP. The coefficient of variation (CV) was calculated for all individual parameters to assess their variability. RESULTS: The time response of the ocular haemodynamic variables was not different between the groups. Most of the outcome variables showed significantly larger fluctuations in patients with POAG compared with healthy controls (CV: FPA: 0.085 (SD 0.033) vs 0.054 (0.029), p = 0.012; CHBF: 0.082 (0.030) vs 0.052 (0.023), p = 0.005; ONHBF: 0.086 (0.044) vs 0.059 (0.032), p = 0.063). These changes were not associated with OPP or IOP. Changes over time correlated among the different ocular haemodynamic outcome measures in patients with POAG (r = 0.678, r = 0.557, r = 0.545; p<0.04) but not in the control subjects (r = 0.336, r = -0.227, r = -0.130; p>0.22). CONCLUSION: Patients with POAG show a larger diurnal fluctuation of ocular blood flow parameters. These fluctuations appear not to be related to a higher statistical error of the applied measurement techniques in POAG patients. These data support the hypothesis that POAG is associated with vascular dysregulation.

Retinal nerve fiber layer birefringence evaluated with polarization sensitive spectral domain OCT and scanning laser polarimetry: a comparison.

A polarization-sensitive spectral domain optical coherence tomography (PS-SD-OCT) system is used to measure phase retardation and birefringence of the human retinal nerve fiber layer (RNFL) in vivo. The instrument records three parameters simultaneously: intensity, phase retardation and optic-axis orientation. 3D data sets are recorded in the optic nerve-head area of a healthy and a glaucomatous eye, and the results are presented in various ways: En-face phase-retardation maps of the RNFL are generated from the recorded 3D data and results are compared with scanning laser polarimetry (SLP). The depth information provided by OCT is used to segment the RNFL in the intensity image and measure the RNFL thickness. From the retardation and thickness data, 2D birefringence maps of the RNFL are derived. Circumpapillary plots of RNFL retardation and thickness obtained by PS-SD-OCT are quantitatively compared with those obtained by SLP.

Sub-wavelength ripples in fused silica after irradiation of the solid/liquid interface with ultrashort laser pulses.

Laser-induced backside wet etching (LIBWE) is performed using ultrashort 248 nm laser pulses with a pulse duration of 600 fs to obtain sub-wavelength laser-induced periodic surface structures (LIPSS) on the back surface of fused silica which is in contact with a 0.5 mol l(-1) solution of pyrene in toluene. The LIPSS are strictly one-dimensional patterns, oriented parallel to the polarization of the laser radiation, and have a constant period of about 140 nm at all applied laser fluences (0.33-0.84 J cm(-2)) and pulse numbers (50-1000 pulses). The LIPSS amplitude varies due to the inhomogeneous fluence in the laser spot. The LIPSS are examined with scanning electron microscopy (SEM) and atomic force microscopy (AFM). Their power spectral density (PSD) distribution is analysed at a measured area of 10 µm × 10 µm. The good agreement of the measured and calculated LIPSS periods strongly supports a mechanism based on the interference of surface-scattered and incident waves.

Medical interventions for primary open angle glaucoma and ocular hypertension.

BACKGROUND: Primary open angle glaucoma (POAG) is a progressive optic neuropathy with an elevated intraocular pressure (IOP), where the optic nerve head becomes pathologically excavated and the visual field (VF) is characteristically altered. Ocular hypertension (OHT) is a condition with elevated IOP but without discernible pathology of the optic nerve head or the VF. It is a major risk factor for development of POAG. OBJECTIVES: To assess and compare the effectiveness of topical pharmacological treatment for POAG or OHT to prevent progression or onset of glaucomatous optic neuropathy. SEARCH STRATEGY: We searched CENTRAL, MEDLINE and EMBASE in May 2007. We searched the bibliographies of identified articles and contacted experts, investigators and pharmaceutical companies for additional published and unpublished studies. SELECTION CRITERIA: Randomised controlled trials comparing topical pharmacological treatment to placebo, no treatment or other treatment for specified endpoints which included people with POAG or OHT, and with duration of treatment of at least one year. DATA COLLECTION AND ANALYSIS: Two authors independently extracted data and assessed trial quality. Where appropriate, we summarised data using Peto odds ratio and mean difference after testing for heterogeneity between studies. MAIN RESULTS: We included 26 trials, which randomised 4979 participants, in this review. Meta-analysis of 10 trials clearly demonstrated reduction of onset of VF defects in treated OHT (OR 0.62, 95% CI 0.47 to 0.81). No single drug showed a significant VF protection compared to placebo or untreated controls. We did identify some border line evidence for a positive influence of treatment on VF prognosis (OR 0.67, 95% CI 0.45 to 1.00) for the beta-blockers . AUTHORS' CONCLUSIONS: The results of this review support the current practice of IOP lowering treatment of OHT. A visual field protective effect has been clearly demonstrated for medical IOP lowering treatment. Positive but weak evidence for a beneficial effect of the class of beta-blockers has been shown. Direct comparisons of prostaglandins or brimonidine to placebo are not available and the comparison of dorzolamide to placebo failed to demonstrate a protective effect. However, absence of data or failure to prove effectiveness should not be interpreted as proof of absence of any effect. The decision to treat a patient or not, as well as the decision regarding the drug with which to start treatment, should remain individualised, taking in to account the amount of damage, the level of IOP, age and other patient characteristics.

Effect of dorzolamide and timolol on ocular blood flow in patients with primary open angle glaucoma and ocular hypertension.

BACKGROUND: There is evidence that perfusion abnormalities of the optic nerve head are involved in the pathogenesis of glaucoma. There is therefore considerable interest in the effects of topical antiglaucoma drugs on ocular blood flow. A study was undertaken to compare the ocular haemodynamic effects of dorzolamide and timolol in patients with primary open angle glaucoma (POAG) or ocular hypertension (OHT). METHODS: One hundred and forty patients with POAG or OHT were included in a controlled, randomised, double blind study in two parallel groups; 70 were randomised to receive timolol and 70 to receive dorzolamide for a period of 6 months. Subjects whose intraocular pressure (IOP) did not respond to either of the two drugs were switched to the alternative treatment after 2 weeks. Scanning laser Doppler flowmetry was used to measure blood flow in the temporal neuroretinal rim and the cup of the optic nerve head. Pulsatile choroidal blood flow was assessed using laser interferometric measurement of fundus pulsation amplitude. RESULTS: Five patients did not respond to timolol and were changed to the dorzolamide group, and 18 patients changed from dorzolamide treatment to timolol. The effects of both drugs on IOP and ocular perfusion pressure were comparable. Dorzolamide, but not timolol, increased blood flow in the temporal neuroretinal rim (8.5 (1.6)%, p<0.001 versus timolol) and the cup of the optic nerve head (13.5 (2.5)%, p<0.001 versus timolol), and fundus pulsation amplitude (8.9 (1.3)%, p<0.001 versus timolol). CONCLUSIONS: This study indicates augmented blood flow in the optic nerve head and choroid after 6 months of treatment with dorzolamide, but not with timolol. It remains to be established whether this effect can help to reduce visual field loss in patients with glaucoma.

Effect of trabeculectomy on ocular blood flow.

BACKGROUND/AIM: Current evidence suggests that vascular insufficiencies in the optic nerve head play an important part in the pathogenesis of glaucomatous optic neuropathy. Trabeculectomy is the most common operative procedure for the treatment of medically uncontrolled glaucoma. This study was conducted to investigate whether trabeculectomy may improve ocular haemodynamics. METHODS: 30 patients with primary open angle glaucoma about to undergo trabeculectomy were included in the study. Patients were evaluated before surgery and at 2 and 10 weeks after trabeculectomy. Optic nerve head blood flow (OnhBF) was assessed with scanning laser Doppler flowmetry. Fundus pulsation amplitude (FPA) measurements were obtained with laser interferometry. RESULTS: Because of the decrease in intraocular pressure there was a significant increase in ocular perfusion pressure (OPP) following trabeculectomy (18.5% (SD 12.0%) and 19.0% (17.1%) at 2 and 10 weeks postoperatively; p <0.001). A significant increase in OnhBF was observed after trabeculectomy (11.6% (16.4%) and 16.2% (20.2%) for each postoperative visit, respectively; p <0.001). FPA was also significantly higher compared with baseline values (17.2% (17.3%) and 17.4% (16.3%), respectively; p <0.001). A significant association between the increase in OPP and the increase in OnhBF and FPA was observed 10 weeks after surgery (r = 0.47; p = 0.009, and r = 0.50; p = 0.005, respectively). CONCLUSION: The results of this study suggest that trabeculectomy improves ocular blood flow in patients with chronic open angle glaucoma.

Effect of nimodipine on ocular blood flow and colour contrast sensitivity in patients with normal tension glaucoma.

AIM: To investigate the effects of oral nimodipine on ocular haemodynamic parameters and colour contrast sensitivity in patients with normal tension glaucoma (NTG). DESIGN: The study was performed in a randomised, placebo controlled, double masked, crossover design. PARTICIPANTS: Nimodipine (60 mg) or placebo was administered to 14 consecutive NTG patients. METHODS: The effects or oral nimodipine or placebo on ocular and systemic haemodynamic parameters and colour contrast sensitivity along the tritan axis were studied two hours after administration. Optic nerve head blood flow (ONHBF) and choroidal blood flow (CHBF) were assessed with laser Doppler flowmetry. Ocular fundus pulsation amplitude (FPA) was measured with laser interferometry. Colour contrast sensitivity (CCS) was determined along the tritan colour axis. MAIN OUTCOME MEASURES: ONHBF, CHBF, FPA, intraocular pressure and CCS were assessed in patients with NTG. RESULTS: Mean ocular FPA increased by 14% (SD 14%) (p = 0.0008), ONHBF by 18% (SD 16%) (p = 0.0031), and CHBF by 12% (SD 14%) (p<0.001) after administration of nimodipine. Nimodipine also decreased the threshold of colour contrast sensitivity along the tritan colour axis (-14% (SD 12%); p = 0.048). However, individual changes in FPA, ONHBF, or CHBF were not correlated with changes in threshold of CCS along the tritan colour axis. CONCLUSIONS: The results indicate that nimodipine increases ONH and choroidal blood flow in NTG patients and improves CCS. The latter effect does not, however, seem to be a direct consequence of the blood flow improvement.

[Modern diagnostic methods for suspected glaucoma and glaucoma]. / Moderne diagnostische Verfahren bei Glaukomverdacht und Glaukom.

BACKGROUND: Diagnosis of early glaucomatous damage as well as the detection of glaucomatous change are still difficult tasks. During the last years numerous new diagnostic techniques have been investigated and some of them have been introduced to the market. METHODS: This paper reviews the different aims of diagnostic technologies in the field of glaucoma. Methods appearing suitable for a large-scale use by ophthalmologists will be judged according to their suitability to meet the goals of early diagnosis, objective diagnosis, progression analysis and screening. CONCLUSIONS: The new diagnostic techniques have not yet greatly influenced our diagnostic procedure. This is mainly due to the fact that, for the most difficult borderline cases of glaucoma, these methods are of limited value, or have not yet been sufficiently investigated. Nevertheless, the Heidelberg retina tomograph (HRT), the nerve fiber analyzer GDX, short wavelength perimetry (SWAP), and the frequency doubling test (FDT) may play a role in these cases. For follow-up, HRT and GDx have proven valuable, especially in early stages of the disease. The very short testing time of FDT together with good specificity qualifies this test for glaucoma screening.

Surgical strategies in patients with combined cataract and glaucoma.

PURPOSE OF REVIEW: In the elderly population, the combined presence of cataract and glaucoma is a frequent condition. In this situation, several surgical options are possible: cataract surgery only and later maybe trabeculectomy, trabeculectomy only and later maybe cataract surgery, or combined cataract and glaucoma surgery. This review compares the different surgical options on the basis of their achievable postoperative intraocular pressure (IOP) level and success and complication rates. RECENT FINDINGS: The impression of better IOP regulation with trabeculectomy than with phacotrabeculectomy has been recently confirmed by an evidence-based review. Contrary to this finding, the success of deep sclerectomy or trabeculotomy does not seem to be compromised by simultaneous phacoemulsification. In eyes with previous glaucoma-filtering surgery, cataract surgery with clear corneal incision has no effect on mean IOP but increases the 3-year failure probability. For phacotrabeculectomy, moderate evidence of a beneficial effect of MMC on IOP regulation and only weak evidence for separating the incisions has been recently reported by another evidence-based review. SUMMARY: The choice of the preferred surgical method depends on the target pressure, the amount of glaucomatous damage, and the grade of visual disturbance caused by the cataract. Phacotrabeculectomy combined with mitomycin C achieves the best IOP lowering of all types of combined cataract and glaucoma surgery currently possible but is associated with potentially sight-threatening complications. In the absence of a low target pressure, phacotrabeculotomy or the combination of phacoemulsification with viscocanalostomy or deep sclerectomy may be the therapy of choice.

Interventions for normal tension glaucoma.

BACKGROUND: Normal tension glaucoma is a clinical condition in which the optic nerve is pathologically excavated and the visual field is disturbed. Nevertheless it has been assumed that intraocular pressure plays a role in the progression of visual field defects in this disease, but other, mainly vascular factors, have been discussed as well. OBJECTIVES: The objective of this review is to assess the effects of medical and surgical treatments for normal tension glaucoma. SEARCH STRATEGY: Trials were identified from the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Group trials register), MEDLINE, EMBASE and BIOSIS Previews. Bibliographies of identified trials were searched to find additional trials. In addition, investigators and pharmaceutical companies were contacted. Date of last search: January 2001. SELECTION CRITERIA: This review includes randomised controlled trials in which medical or surgical interventions were compared to no treatment, placebo or other treatment in people with normal tension glaucoma. Two reviewers independently assessed the full text copies of the possibly relevant trials. Trial quality was assessed according to the methods set out in Section 6 of the Cochrane Reviewers' Handbook (Clarke 2000). DATA COLLECTION AND ANALYSIS: Data were extracted by two reviewers and results were compared for differences. Discrepancies were resolved by discussion. The heterogeneity of interventions, follow-up periods and outcomes did not allow for statistical combinations of the study results. MAIN RESULTS: According to the selection criteria on visual field loss, eight studies were included in this review. Only three studies focussed on patient relevant outcomes. In one trial a beneficial effect of lowering intraocular pressure was found, but only if data were corrected for cataract development. In two small studies a beneficial effect on visual field loss of brovincamine, a calcium antagonist was reported. REVIEWER'S CONCLUSIONS: In one study the effect of intraocular pressure lowering on visual field outcome was only significant when data were corrected for cataract development. The results for calcium antagonists are promising, but larger trials have to be performed. Studies that focussed on reduction of intraocular pressure or haemodynamic variables are not necessarily relevant for the outcome in people with normal tension glaucoma.

Modifying subsceral fluid pressure in an experimental model of mitomycin-C diffusion.

BACKGROUND: Episcleral application of mitomycin-C (MMC) during glaucoma filtration surgery hinders the post-operative wound healing. Diffusion through the sclera might result in a toxic effect on the ciliary body resulting in reduced aqueous humor production leading to post-operative hypotony. We developed an experimental model to investigate the influence of intraocular pressure on the diffusion of MMC through the sclera and in subscleral compartments. METHODS: Scleral quadrants of 10 human donor eyes were mounted on PMMA tubes filled with saline imitating the intraocular volume. By height variation of a coupled infusion line different intraocular pressures were simulated (0, 8, 23 and 80 mmHg). Additionally the model included a subscleral sponge to mimic the compartment of the ciliary body. The episcleral sides of the scleral quadrants were exposed for 1 min to sponges soaked with 200 microg ml(-1) MMC. An 8-mm-diameter scleral disk was punched out with a trephine and horizontally dissected with a kryotome. The MMC concentrations of scleral layers, epi-and subscleral sponges and the fluid within the tubes were analysed by means of high-performance liquid chromatography. RESULTS: The MMC concentration gradually declined from the episcleral sponge (165 microg ml(-1)) to the superficial (3.3 microg ml(-1)) and deep scleral layers (1.2 microg ml(-1)), and to the subscleral sponge (0.2 microg ml(-1)). We were able to detect very small concentrations of MMC in the fluid within the PMMA tubes (0.01 microg ml(-1)). CONCLUSION: We developed a new experimental in vitro model for investigating transscleral MMC diffusion. The different simulated intraocular pressures had no effect on the concentration gradient through the investigated compartments of our model.

Activity of dissolved mitomycin C after different methods of long-term storage.

PURPOSE: The cytostatic substance mitomycin C (MMC) is used in trabeculectomy to enhance the success rate in problematic cases and is usually dissolved immediately before application, but only approximately 1% of the substance is needed for treatment. The authors evaluated different methods of long-time storage of MMC for a period of 6 months. METHODS: MMC in concentrations of 0.02, 0.05, 0.1, 0.2, and 0.4 mg/mL was prepared at the local pharmaceutical department and stored at +22 degrees C (room temperature), +4 degrees C (refrigerator), -20 degrees C (freezer compartment), and -196 degrees C (liquid N2). The activity of MMC was evaluated with a microagar diffusion method (bioassay) after 30 minutes, and 1, 3, 7, 14, 30, 90, and 180 days for the different concentrations and storage methods. RESULTS: There was no difference in the long-term stability of the investigated MMC concentrations. Ninety percent of the initial activity was preserved after storage at +22 degrees C for 1 week, -20 degrees C for 1 month, or +4 degrees C for 3 months. At 6 months the activities were 16%, 48%, and 78% of the initial values, respectively. The activity of MMC stored at -196 degrees C is not reduced after storage for 6 months. CONCLUSIONS: Dissolved MMC can be stored in the refrigerator for up to 3 months without significant loss of activity. Storage at room temperature is not recommended. Costs of trabeculectomy can be reduced by storage of reconstituted solutions rather than dissolving MMC before each glaucoma surgery.

A double masked placebo controlled study on the effect of nifedipine on optic nerve blood flow and visual field function in patients with open angle glaucoma.

AIMS: To investigate whether nifedipine affects ocular perfusion or visual fields in open angle glaucoma patients. METHODS: In a parallel group study nifedipine or placebo was administered for 3 months (n = 30). Ocular fundus pulsation amplitude (FPA), cup blood flow (Flowcup) and visual field mean deviation (MD) were measured. RESULTS: Five patients receiving nifedipine discontinued due to adverse events. Nifedipine did not affect FPA [difference: 0.3 microm (95% CI -0.3,0.9); P = 0.70], Flowcup: [difference: -9 rel.units (95% CI -133,114); P = 0.99], or MD [difference: 0.2dB (95% CI -2.2,2.7); P = 0.51] vs placebo. CONCLUSIONS: Systemic nifedipine is not well tolerated in glaucoma patients and exerts no effect on visual fields or ocular perfusion.

[Excimer laser versus diamond fraise: equal short-term outcome of corneal smoothing in pterygium operations]. / Excimer-Laser versus Diamantschleifer: Gleichwertige Kurzzeitergebnisse bei Hornhautglättung nach Pterygiumoperationen.

BACKGROUND: The treatment of pterygia often results in irregular astigmatism. Corneal smoothing at the end of surgery plays a major role in the development of astigmatism. The aim of our study was to compare the efficiency of corneal smoothing performed by phototherapeutic keratectomy compared with the conventional method performed by a diamond fraise. The effect of postoperative excimer laser smoothing on refraction, visual acuity and irregular astigmatism was investigated. PATIENTS AND METHODS: 32 eyes underwent pterygium excision using a standardized surgical procedure. In addition 9 eyes underwent postoperative phototherapeutic keratectomy of the wound region with an excimer laser, 23 eyes were treated with a diamond fraise for corneal smoothing. The postoperative examination was performed 7, 14 and 30 days after surgery. Corneal topography was performed by a computer-assisted videokeratoscope (TMS-1). The results were evaluated by the Fourier transform analysis. RESULTS: Both methods showed similar results concerning refraction and visual acuity postoperatively. Preoperatively all patients had an irregular flattening of the corneal topography in the area of the pterygium. Postoperatively a small irregular flattening was left in eyes treated with a diamond fraise. In the excimer laser treated group a steepening in the corneal topography could be observed. CONCLUSIONS: The phototherapeutic keratectomy with excimer laser in the treatment of pterygia suggests to be a gentle alternative creating a smooth wound surface. Despite of this advantage the treatment with the excimer laser effects a remarkable increase in administration and expense.

[Adnexal torsion in childhood]. / Függelékcsavarodás gyermekkorban.

The authors report the case of a 10-year-old girl who was admitted with hypogastric complaints. Based on the examinations followed that, laparotomy was carried out, during which the torsion of the right-side adnexum was observed. During the case report special attention is put on the differential-diagnostic difficulties of adnexal torsion. The importance of the case is that we should think of this relatively rare disease even in childhood, because the early diagnosis and adequate therapy make possible to avoid the surgical amputation.

Tritan colour contrast sensitivity function in refractive multifocal intraocular lenses.

AIMS: To compare tritan colour contrast sensitivity (CCS), without and with glare, in patients with refractive multifocal intraocular lenses (IOLs) and with monofocal intraocular lenses. METHODS: Tritan CCS was determined (Moorfields Vision System, CH Electronics) in 15 eyes (14 patients, 75.7 (+/-6.6) years) with a refractive multifocal IOL (Allergan SA 40N) and in 11 eyes (10 patients, 73.7 (+/-6.4) years) with a monofocal IOL (Allergan SI 40 NB). Measurements were made monocularly under mesopic conditions at a distance of 2 metres from the monitor with best distance refraction plus 0.5 D at 0.5, 1, 3, 6, 11.4, and 22.8 cycles per degree (cpd). The test was then repeated for the multifocal IOLs, adding minus 2.5 D to the best distance refraction to force the patient to use the near focus. Both lenses were also investigated under glare conditions with the same set-up and using the brightness acuity tester (BAT). RESULTS: The tritan CCS function without glare in multifocal lenses through the distance focus was nearly identical to that through the near focus. The following statistically significant differences were measured: the CCS function without glare for the multifocal lens was worse at 0.5 cpd and 1.0 cpd than that of the monofocal lens. In CCS testing of the multifocal group with glare at 6 cpd, the results through the distance focus were better than the results through the near focus. For the CCS function with glare, the values for the distance focus in the multifocal lens were worse than the values for the monofocal lens at 0.5 cpd and 1 cpd. In CCS testing with glare through the near focus and CCS testing through the monofocal lens, the monofocal lens performed better at 0.5 cpd, 1 cpd, 3 cpd, and 6 cpd. CONCLUSION: Refractive multifocal intraocular lenses influence tritan CCS function compared to monofocal lenses.

Impact of Mitomycin-C application time on the scleral Mitomycin-C concentration.

The aim of this study was to determine the effect of varying the application time of Mitomycin-C (MMC) on the scleral concentration of MMC. The sclerae of 14 human donor eyes were used for this study. The episcleral sides of the 4 scleral quadrants of each donor eye were exposed for 0.5, 1, 3 and 5 min to round, 8 mm-diameter sponges soaked with 50 microl of 0.2 mg/ml MMC. After 40-ml irrigation with saline, a central 8-mm diameter scleral disk was punched out, homogenized and analyzed with high performance liquid chromatography (HPLC). The scleral MMC concentrations (microg/g) after 0.5, 1, 3 and 5 min application times were 6.40 (+/-3.38), 9.02 (+/-2.40), 12.31 (+/-3.37), and 13.97 (+/-3.83). The differences of scleral MMC concentration in paired t-tests were statistically significant comparing 0.5 with 1 and 1 with 5 min application. However the effect was relatively small within the range of usual application times (1 to 5 min), and 64% of the MMC was delivered to the sclera within the first min.