Nikica Gabrić

Treatment of anti-vascular endothelial growth factor-resistant diabetic macular edema with dexamethasone intravitreal implant.

Purpose: To investigate the efficiency of intravitreal dexamethasone implant in patients with chronic diabetic macular edema nonresponsive to three consecutive monthly intravitreal injections of anti–vascular endothelial growth factor administered previously. Methods: Fifteen patients (16 eyes) were included in this 4-month prospective clinical trial. Main observed outcomes were the changes between initial and monthly visits in best-corrected visual acuity, central foveal thickness, and intraocular pressure (IOP). Patients included had central foveal thickness of >225 &mgr;m (measured by optical coherence tomography) and were nonresponsive to previously administered 3 consecutive monthly intravitreal injections of 1.25-mg bevacizumab. Administration of intravitreal dexamethasone implant was performed at baseline, and patients were followed-up monthly. Results: Statistically significant changes from baseline were observed in best-corrected visual acuity (at 2 months), central foveal thickness (at 1, 2, and 3 months), and IOP (at Months 1, 2, and 3) as follows: mean best-corrected visual acuity significantly increased from 0.29 Snellen lines at baseline to 0.39 lines after 2 months (P = 0.0381). At Months 1, 2, and 3, the mean central foveal thickness significantly decreased, from 462 &mgr;m at baseline, to 366 &mgr;m (P = 0.0343), 346 &mgr;m (P = 0.0288), and 355 &mgr;m (P = 0.0370), respectively. When compared with baseline IOP of 15.38 mmHg (12–19 mmHg), IOP increased significantly at Months 1, 2, and 3: 18.93 mmHg (range, 16–24 mmHg; P = 0.0003), 19.5 mmHg (range, 16–27 mmHg; P = 0.0003), and 17.5 mmHg (range, 15–21 mmHg; P = 0.0048), respectively. Conclusion: Dexamethasone intravitreal implant may present an alternative option in the treatment of chronic diabetic macular edema nonresponsive to three consecutive monthly bevacizumab injections administered previously. However, IOP measures were only slightly increased. It seems that the effect of dexamethasone may last till 4 months after initial injection.

Preparation and Preservation of Amniotic Membrane

The human amniotic membrane (AM) is the innermost layer of the placenta and consists of a single epithelial layer, a thick basement membrane and an avascular stroma. Due to the number of its properties, AM is increasingly used in the treatment of severe ocular surface diseases. The amniotic basement membrane facilitates migration and growth of epithelial cells, therefore promoting epithelialization. The avascular stroma of the AM reduces fibrovascular ingrowth and abnormal neovascularization. Amniotic epithelium produces anti-inflammatory and growth factors beneficial to the treatment of inflammatory corneal diseases. AM is prepared from a fresh placenta under sterile conditions, washed with balanced salt solution containing penicillin, streptomycin, neomycin and amphotericin B, placed in tissue culture and glycerol at a ratio of 1:1, and stored at -80 degrees C. A donor serological test for human immunodeficiency virus and hepatitis B and C viruses has to be all negative. After transplantation of the amniotic membrane (AMT) onto the eye surface, AM will be slowly absorbed within approximately 4-6 weeks. Depending on consumption, amniotic membranes are used up to 1 year after preparation, although many have recommended storage for an indefinite period. Since AM is not a completely transparent tissue, the patients visual acuity may decrease after AMT; the patient should be aware of this temporary effect prior to surgery.

Complications following two methods of posterior chamber intraocular lens suturing.

The aim of this study is to compare complication rates in two different operative techniques applied for the secondary, posterior chamber intraocular lens (PCIOL) implantation with sulcus fixation. 179 eyes with partial or no posterior capsule support underwent surgery. Applied techniques were: transscleral fixation of the IOL by passing with the fixation needle through the sulcus from the inside (70 eyes) or from the outside (109 eyes) of the bulbus. The most frequent intraoperative complications were haemorrhages and vitreous prolaps with no significant difference between used techniques. In the ‘from the inside’ group, following late postoperative complications developed: astigmatism of >4D (24%), cystoid macular oedema (20%), pupil distortion (14%), partial posterior capsule opacification (10%), suture exposure (10%), IOL decentration (8%) and hemophthalmus (3%). In the ‘from the outside’ group same complications showed a decreased rate: 17%, 16%, 8%, 8%, 9%, 5% and 1%, respectively. Other late complications like high intraocular pressure, synechiae and uveitis were adequately represented in both techniques. After 24 months follow-up, best corrected visual acuity ≥0.8 was achieved in 48.5% of eyes when ‘from the inside’ and in 57.7% of eyes when ‘from the outside’ technique was used.

Potential beneficial role of sevelamer hydrochloride in diabetic retinopathy

Patients with chronic kidney disease (CKD) experience co-morbid illnesses, including cardiovascular disease and retinopathy. Sevelamer hydrochloride (Renagel®); a non-calcium phosphate binder reduces coronary artery and aortic calcification as compared to calcium containing phosphate binders and additionally effects inflammatory biomarkers such as C-reactive protein (CRP), and lowers LDL cholesterol in patients with CKD. Since retinopathy is proven to be associated with increased coronary calcification, shared pathophysiological processes may contribute to both microvascular and macrovascular disease. We here suggest three different mechanisms of possible sevelamers influence on the retinopathy: (1) by direct effect on the microvasculature through lowering CRP and LDL, involved in endothelial dysfunction and atherogenesis, (2) indirectly by attenuation of vascular calcification of aorta and carotid internal artery, it reduces ischaemia and improves circulation in the opthalmic artery and hence postponing retinopathy, (3) through hypertension by reducing atherosclerosis and calcification of carotid arteries, sevelamer decreases stiffness and intima-media wall thickness, therefore lowering blood pressure, which is well known to increase progression of diabetic retinopathy. So far no studies have yet been published on the direct influence of sevelamer on the retinopathy which we believe has good theoretical background. With its combined macrovascular and microvascular effect, sevelamer could potentially postpone and/or decrease retinopathy in diabetic patients with hypertension, and that are on hemodialysis or even predialysis patients.

Comparison of Verisyse and Veriflex Phakic Intraocular Lenses for Treatment of Moderate to High Myopia 36 Months after Surgery

ABSTRACT Purpose: To compare refractive stability, endothelial cell count (ECC), incidence of complications, and patients’ satisfaction between a rigid Verisyse (group I, n = 198) and foldable Veriflex (group II, n = 212) phakic intraocular lenses (pIOL) over 36 months postop. Materials and methods: This was a retrospective study. Patients’ satisfaction and incidence of photic phenomena were evaluated at one month and one year postop. Data were analyzed to determine difference between groups for astigmatism, mean spherical equivalent (MRSE), uncorrected (UDVA) and corrected (CDVA) monocular distance visual acuity, complication rate (acute and chronic), and ECC. Differences were considered statistically significant when p < 0.05. Results: Group II cases had significantly higher UDVA, CDVA, and lower astigmatism during the entire follow-up. There was no significant difference in mean MRSE or mean ECC postoperatively. In both groups, mean ECC reduced significantly at one month postop, followed by a gradual linear decline between 1 and 36 months of 22.4 cells/mm2/annum (group I) and 13.32 cells/mm2/annum (group II). Overall complication rates were ≤ 10% with no significant inter-group differences. Group I patients reported lower incidence of halos at one month but more problems with night vision at one year compared with group II. Overall satisfaction was high and total incidence of reported photic phenomena was low. Conclusion: Both Verisyse and Veriflex pIOLs are effective in correcting myopia. The Veriflex lens demonstrated better refractive outcome; however, subclinical inflammation observed in the Veriflex group and potential influence of inflammation on ECC loss require further investigation.

Bowman strip complications during routine LASIK: Two cases demonstrating the clinical advantage of using Mitomicyn C in such cases.

Bowman strip is the term used to describe a portion of Bowman’s layer that remains exposed at the posterior surface of the flap. The incidence of intraoperative complications related to flap creation during LASIK is between 0.19% and 21.2%. Several explanations have been proposed to account for Bowman strip or ‘‘buttonhole’’ complications such as: steep corneas, partially opened eyes, microkeratome deficits such as blade defect and, insufficient synchronization between the movement of the blade and microkeratome translational movement. High astigmatism, or conjunctival entrapment may also lead to Bowman strip or buttonhole flap. Treatment options for Bowman strip appear to depend on the severity of the complications encountered. Some authors recommend waiting three months, relifting the flap, bathing the bed with Mitomicyn C (MMC) followed by surface ablation. In more severe profound cases it is recommended to wait six months, relift the flap, apply of topical MMC, close the flap and re-cutting a new flap. We report our experience of two cases where, the same type of microkeratome and laser platform were used for routine LASIK surgery. In both cases, Bowman strip was encountered with thin strip of epithelium and photo ablation was completed during the two individual surgical events. The only difference was that in one case we applied topical 0.02% Mitomycin C, while in the other the procedure was completed without any additional medications or intervention. Scientific letter

Positive pressure during penetrating keratoplasty can be solved with a modified graft-over-host technique

Purpose:  To describe a modified graft‐over‐host (MGOH) surgical technique which was used to prevent serious complications in cases of positive vitreal pressure during penetrating keratoplasty (PKP) and to compare the endothelial cell density (ECD) loss and clinical outcome between eyes undergoing MGOH or standard PKP.

Treatment of Neovascular Age Related Macular Degeneration

Until the end of the last century, no intervention could alter the natural history of the disease. Only in the last few decades, the retina specialists began to intervene in order to minimize the visual loss in those patients. Last ten years have been especially exciting as the new treatment modalities emerged and for the first time we could not only halt the progression of the deterioration, but rather improve vision in some patients.

Incidence and Clinical Characteristics of Post LASIK Ectasia: A Review of over 30,000 LASIK Cases

ABSTRACT Purpose: To report the incidence of postoperative ectasia after laser in situ keratomileusis (LASIK). Methods: A retrospective case review of 30,167 eyes (16,732 patients) was conducted following LASIK between August 2007 and August 2015. The follow-up was between 2 and 8 years. Tomography was performed after 2 years postop. After identifying cases of ectasia, the charts of these patients were examined to identify any common factors that may have predisposed them to develop ectasia. Results: Ten eyes of seven patients developed post-LASIK ectasia. Eight eyes had been treated for myopia and myopic astigmatism, two eyes for mixed astigmatism. There were no cases of ectasia after LASIK for hyperopia. All 10 cases of ectasia had a flap that was created using the Moria M2 mechanical microkeratome (average flap thickness 118.15 ± 12.88 µm) and refractive error corrected using the Wavelight Allegretto excimer laser. Retrospectively, most prevalent risk factors were thin cornea (≤ 500 µm, 50% of cases), anterior topographic map irregularities (e.g., asymmetric bow tie, 40% of cases), Ectasia Risk Score > 3 (40% of cases), percent tissue thickness alteration ≥ 40% (20% of cases) and low residual stromal bed (≤ 300 µm, 30% of cases). One eye had no identifiable risk factors. In the retrospective chart review 14.97% (4,506) of all the eyes had similar risk factors to the cases that went on to develop ectasia. Conclusion: The incidence of ectasia was 0.033% over 8 years. The incidence could be higher as some cases may destabilize beyond this period and some patients were lost to follow-up asymptomatic of any clinical signs. Other intrinsic factors may trigger the development of post LASIK ectasia. The current widely accepted risk factors are not sufficiently rigorous for screening out potential ectasia from developing after LASIK. There is a need to augment accuracy with higher sensitivity and specificity.

Autologous Neurosensory Retinal Free Flap Treatment for a Large Macular Hole

A patient presented with a large chronic macular hole (MH) of 700 μm. Best-corrected visual acuity (BCVA) was 20/200. Since the MHs edges were attached and stiff, an autologous neurosensory retinal flap was harvested and placed into the MH to close it. Perfluoro-n-octane heavy liquid (PFC) was instilled over the flap and exchanged with silicone oil (1,000 cs). Seven days postoperatively, the MH was closed, with a BCVA of 20/80 that improved to 20/60 at months 1 and 3. Optical coherence tomography and angiography showed patch incorporation with fovea formation and normal circulation. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:e89-e92.].