How to Convert the Obliquely Crossed to Non-Crossed Astigmatism? A Simple Method Using Vector Analysis

The authors discussed about the problem of special form in astigmatism classification. This special type of astigmatism is the form of obliquely crossed astigmatism. In which the meridians, major and minor, are not right angles. In this astigmatism is not possible to prescribing for cylindrical (toric) spectacle lens. Authors describe the Thompson formula for oblique crossed cylinder and observe that this formula is to complicate for calculation new cylinder power. In this reason, the authors create the new formula and simple procedure for this calculation. This simple formula based on vector analysis and read: DM3 = DM2 ´ cos2 b

Comparison of Diffractive and Refractive Multifocal Intraocular Lenses in Presbyopia Treatment

Multifocal intraocular lenses (MFIOL) enable good near and far vision after cataract surgery. Excellent results with cataract patients encouraged ophthalmologists to implant MFIOL after clear lens extraction (CLE). There are two types of MFIOL: diffractive and refractive. In our prospective study we compared clinical outcomes after CLE and bilateral implantation of diffractive (Tecnis Multifocal), (N = 100 eyes, 50 patients) and refractive (ReZoom), (N = 100 eyes, 50 patients) MFIOL to patients with presbyopia and hyperopia. Near and distant uncorrected visual acuity (UCVA), spectacle dependency, subjective satisfaction and visual disturbances were measured and compared between two groups. Patients achieved good near and distant UCVA in both groups. »Tecnis« group had better near UCVA (statistically not significant) and less night time visual disturbances. »ReZoom« group reported less problems with intermediate vision. Diffractive and refractive MFIOL enable high rate of spectacle independency to presbyopic hyperopic patients with low rate of side-effects. Refractive MFIOL provide better intermediate vision and diffractive slightly better near vision and less haloes and glare

Presbyopia Correction During Cataract Surgery with Multifocal Intraocular Lenses

Introduction: The first generations of multifocal intraocular lenses (MFIOLs) were designed to provide patients good distance and near vision, but intermediate was not satisfactory. Trifocal, a bifocal of low-add and quadrifocal MFIOLs were invented, offering possibility to correct vision for distance, near, and intermediate tasks. The novel IOL, extended range of vision (EROV), is covering mostly intermediate and distance vision, with lower level of photic phenomena

Curvature Analyses of the Corneal Front and Back Surface

In 25 eyes, age range 60–80 years, in purpose of preoperative treatment prior to cataract surgery, measurements of the radius of curvature as well as main meridians of the anterior and posterior corneal surfaces were performed. Average value of the curvature of the anterior corneal surface (R1) was R1=7.84 mm, while posterior radius (R2) was 6.4mm. Main meridian of the anterior corneal surface was in 70% in plus value (+), while postrerior main meridian was always in minus value. It is very important to highlight that main corneal meridians R1 and R2 always cross outside the 90° angle. That is why the combination of the calculation based on the two main meridians superposition (overrefraction) as a form of crossed cylinders has to be calculated (Astigmatismus directus seu obliquus decusatus) using special formula. One of that kind of formulas is Thompson’s. Authors want to emphasise the importance of the optical calculation of the posterior corneal surface in the refractive surgery

Resolution of Pseudophakic Cystoid Macular Edema with Combination Therapy of Topical Corticosteroids and Nonsteroidal Anti-inflammatory Drugs

A 69 years old women underwent uneventful cataract surgery of her left eye with phacoemulsification and posterior chamber intraocular lens implantation in topical anesteshia. Patinet was postoperatively treated with combination of antibiotic and steroid in decreasing dosages during five weeks: one drop five times a day the first week, three times a day second to forth week and one time a day the fifth week. In each checkup, performed first postoperative day, 7 days, 5 weeks and 12 weeks after the operation, visual acuity with and without correction, tonometry, corneal transparency, biomicroscopy of posterior pole and measure of macular thickness by optical coherence tomography (OCT) were performed. At first day follow-up visit, the patient’s visual acuity was 20/25 but 6 weeks after the operation, the patient’s vision had worsened to 20/60 after a slow steroid tapper. At that time OCT showed foveal thickening and cystic changes specific for cystoid macular edema (CME). Combination of corticosteroid and non-steroidal anti-inflammatory drug four times daily was included in therapy. The dose was tapered off over the ensuing 8 weeks. The total treatment duration was 12 weeks. At the patient’s 2-month follow-up visit, vision has improved to 20/20 and the fovea appeared flat. OCT showed complete resolution of foveal thickening and cystic changes. Combination of corticosteroid and NSAID is effective and safe therapy for treating pseudophakic CME. Patient showed significant improvement in visual acuity and retinal thickness at 2 months post treatment. Abbreviations: OCT – optical coherence tomography, CME – cystoid macular edema, NSAID – non-steroidal anti-inflammatory drug