Journal of Current Ophthalmology
Volume:26 Issue: 3, Sep 2014

In this issue of IRJO Khabazkhoob and coauthors have presented “Validity of uncorrected visual acuity measured in vision screening programs for detecting refractive errors”. They have investigated 3,675 first year primary school children from seven cities of Iran through multistage cluster sampling. All students have uncorrected vision of 20/20. The authors found 1.14% of myopia, 8.07% of hyperopia, and 11.11% of astigmatism. They indicated that measurement of visual acuity alone is not sufficient for screening programs with many false negative results and cycloplegic refraction should be added to the programs to prevent any complication caused by refractive errors.

Uncorrected visual acuity is the only variable measured in vision screening programs in many countries worldwide. The aim of this study was to calculate the sensitivity, specificity, and predictive value of the uncorrected visual acuity in the screening programs for the diagnosis of refractive errors. In this cross-sectional study, of 4,157 students in the first year of primary school who were selected from seven cities of Iran through multistage cluster sampling, 3,675 students participated in the study. In each school, measurement of corrected and uncorrected visual acuity, cycloplegic and non-cycloplegic refraction, and cover test were performed for all students by an optometrist. Refractive errors obtained by cycloplegic refraction were considered gold standard and the validity of uncorrected visual acuity measured in the screening program for the diagnosis of refractive error was calculated. In students with visual acuity of 20/20, the prevalence of myopia, hyperopia and astigmatism was 1.14%, 8.07% and 11.11%, respectively. The sensitivity of uncorrected visual acuity in the screening program for the diagnosis of myopia, hyperopia, astigmatism, and ametropia was 25.33%, 12.81%, 14.34%, and 12.64%. The area under the ROC curve of uncorrected visual acuity by optometrist and the screening program only showed a significant difference in myopia (p=0.013). The measurement of visual acuity in screening programs is not useful per se in the diagnosis of refractive errors and has a high percentage of false negative results. Adding refractive error examinations to the protocol of screening programs can increase their efficacy.Iranian Journal of Ophthalmology 2014;26(3):121-8 © 2014 by the Iranian Society of Ophthalmology

To determine the prevalence of refractive errors in the students of Mashhad University of Medical Sciences, Iran In this cross-sectional study, we used cluster sampling for selecting participants from every department of Mashhad University of Medical Sciences, proportional to the number of students in each department. Each participant received refraction examination with an auto-refractometer and check up with a retinoscope. Myopia and hyperopia were defined as spherical equivalent (SE) less than -0.5 and more than +0.5 D, respectively. Astigmatism was defined as cylinder power worse than 0.5 D. Out of 1,745 selected individuals, the data of 1,431 participants were analyzed after implementing the exclusion criteria; 58.8% of the participants were female and the mean age of the participants was 23.8±3.8 years (range, 18-32 years). Myopia, hyperopia, and astigmatism were seen in 41.7% (95%CI 38.7-44.7), 7.8% (95%CI 6.2-9.4), and 25.6% (95%CI 23-28.3) of the students in this study, respectively. The prevalence of myopia increased significantly with age (OR=1.16 1.12-1.20 p<0.001). The prevalence of hyperopia was significantly higher in females (OR=2.1 1.1-3.7 p=0.025) and decreased significantly with age (OR=0.87 0.81-0.94 p=0.001). The prevalence of astigmatism increased significantly with age. Moreover, 6% of the students had anisometropia and 1.2% had high myopia. The prevalence of myopia was considerably high in these students; therefore, attention to this age group to identify and correct the refractive errors should receive priority in the health system.

To assess the stability of visual and refractive outcomes that was compared between three and 12 months after MyoRing implantation in moderate and severe keratoconus This study included 54 eyes of 50 patients (27 males and 23 females) with stage II and III keratoconus who underwent MyoRing (Dioptex GmbH) implantation. Clinical outcomes including uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, spherical equivalent (SE) and mean keratometry (k)- readings were compared preoperatively and postoperatively (follow-up times were at 1, 3, 6 and 12 months postoperation). The mean age was 28.48±6.3. The mean UDVA (logMAR) and the mean CDVA (logMAR) improved significantly from 1.20±0.24 to 0.20±0.09 and from 0.58±0.22 to 0.14±0.06, respectively (p<0.001). Both SE and the maximum keratometry (k)-reading decreased significantly by six diopters (p<0.001). There was no significant difference in visual and refractive outcomes between three and 12 months postoperatively. Twelve months after MyoRig implantation the predictability was 47 eyes (87%) within ±1.00 D and 31 eyes (57%) within ±0.50 D of emmetropia. MyoRing implantation in keratoconic patients improves SE, UDVA and CDVA significantly. Additionally, the improvement in UDVA was remarkable (approximately 10 lines). The procedure was safe and effective in treatment of patients with moderate and severe keratoconus. The visual and refractive outcomes remained stable between three and 12 months postoperatively.

To evaluate visual function in patients with different types of light-filtering intraocular lenses (IOLs) In this prospective comparative clinical study Cataract patients with different types of IOLs in Khatam-al-Anbia Eye Hospital, Mashhad were enrolled and followed for three months postoperatively. Corrected distance visual acuity (CDVA), color discrimination under photopic (1000 lux) and mesopic (40 lux) conditions were evaluated with Roth 28 hue test. Contrast sensitivity testing was then performed with 1000E contrast sensitivity unit (CSV-1000E, vector vision) with a constant test luminance level of 85 cd/m2. In this study, 47 patients were evaluated with different IOLs (16 clear, 17 yellow, 14 photochromic). There were no significant differences between the three IOLs in CDVA, contrast sensitivity and mesopic and photopic color vision (p<.05). Contrast sensitivity as well as the mesopic and photopic color vision are not different in clear, yellow and photochromic IOLs.

To evaluate the results of one-site phacotrabeculectomy using sutureless tunnel technique without peripheral iridectomy (no-PI) in glaucoma patients with cataract A retrospective study of cases which has been recorded of patients who have had one-site no-PI phacotrabeculectomy using sutureless tunnel technique. We collected pre- and postoperative data in all patients including best corrected visual acuity (BCVA), intraocular pressure (IOP) and the number of anti-glaucoma medications. Surgical success was defined as the final IOP<21 mmHg and ≥20% reduction from preoperative IOP for criteria A, and final IOP<18 mmHg and ≥30% reduction from baseline for criteria B. Success was further divided into incomplete when anti-glaucoma medications were needed postoperatively and complete when no anti-glaucoma medications were used). Forty eight eyes of 48 patients were recruited into the study. Mean (SD) age of the patients was 70.1 (8.8) years. Mean value of IOP before surgery was 27.1 (SD=6.4), and it decreased significantly at all follow-up visits after surgery (p<0.001). At final follow-up, mean IOP was 15.8 (SD=3.7) mmHg (p<0.001). Mean number of anti-glaucoma medications decreased from 2.6 (SD=1.2) preoperatively to 0.7 (SD=1.4) at the last follow-up visit (p<0.001). Mean logMAR BCVA improved from preoperative level of 0.97 to 0.33 at the final follow-up visit (p<0.001). For criteria A, qualified and complete success rates were 81.2% and 64.6%, and for criteria B these rates were 66.7% and 56.2%, respectively. One-site no-PI sutureless tunnel phacotrabeculectomy leads to a significant reduction in IOP and helps to improve visual acuity in glaucoma patients with cataract.

To evaluate the rate of optical coherence tomography (OCT) grid decentration in a routine practice and its effect on thickness measurements Topcon spectral domain OCT scans from various macular diseases including age related macular degeneration, diabetic macular edema, macular pucker and central serous chorioretinopathy (CSCR) were studied in all patients visited during seven consecutive days. In each scan, the macular EDTRS grid was evaluated for decentration. After grid adjustment, the changes in central subfield thickness (CST) measurements were recorded. Differences >1 µm and >8.5 µm between automatically determined and manually adjusted CST measurements were recorded as grid decentration and significant grid decentration. Ninety-three OCT scans of 93 eyes were evaluated. Thirty-three scans were unreliable for grid adjustment. In the remaining 60 eyes, grid decentration was found in 32 eyes (53.3%). The mean change in CST after grid adjustment was 41.1±55.01 (3-251) microns. Clinically significant CST changes were found in 24 eyes (40%). No significant relationship was found between underlying disease and corrected CST, and grid decentration. Abnormal retinal thickness map was found in a significant number of scans. Topcon OCT scans should be evaluated routinely for grid decentration.

To determine the prevalence of intraocular injuries in patients with blow-out fracture and also to evaluate the etiologic mechanism of orbital blow-out fractures This study is a consecutive case series analysis of 116 patients with orbital blow-out fractures. The patients were visited by an ophthalmologist within 24 hours of trauma. Ninety-one men and twenty-five women with mean age of 29.1±13.9 years were included for this study. Fist trauma and assault (54%) was the most common cause of orbital blow-out fractures. Inferior wall was involved more commonly (49%) than medial wall and combined form. Significant enophthalmos (>2 mm) was present in 26 cases. Orbital reconstruction surgery was performed in 34% of cases. Intraocular injuries were detected in 25% of patients. Hyphema (65%) and commotio retina (39%) were the most frequent detectable intraocular injuries. Intraocular damages were significantly less common in patients with large fractures (synchronous medial and inferior wall fractures or fracture size equal or more than 1/2 of orbital wall) in contrast to small size fractures (p=0.02). Ocular injuries are relatively common in blow out fractures and ophthalmic examination is mandatory. In our study ocular injuries were less frequent in large fractures than small size fractures that may indicate protective role of orbital integrity or other factors caused by fractures.

To evaluate the effect of stenosis nature on success of silicone intubation for nasosolacrimal duct stenosis (NLDS) in adults (patent nasolacrimal duct with resistance to positive-pressure irrigation) An interventional case series of consecutive monocanalicular and bicanalicular silicone intubation for nasolacrimal duct stenosis in adults were reviewed. The severity of the stenosis was classified by the surgeon as simple (defined as an easy passage during the probing procedure) or tight (defined as a resistance along the nasolacrimal duct with difficulty in probe passage). Treatment success was defined as the complete resolution of epiphora or intermittent epiphora with normal dye disappearance test at one year after tube removal. The study were included a total of 49 eyes of 37 patients (21 females and 16 males). The mean age at the time of surgery was 49.45±19.22 years (range, 14-79 years). Simple stenosis was found in 31 eyes (63.3%) and tight stenosis was found in 18 eyes (36.7%). Treatment success was achieved in 35 of 49 eyes (71.4 %). There was a statistically insignificant increase in treatment success of intubation in tight stenosis (88.8%) compared with simple stenosis (61.2%) (p=0.05). Silicone intubation was more successful in eyes with tight nasolacrimal duct stenosis. However, the severity of the stenosis was not a predictive factor for intubation failure.

To describe a case with a rare complication of posterior chamber intraocular lens (PC-IOL) implantation in a patient who had undergone extracapsular cataract extraction (ECCE) two years before Case report: A 80-year-old diabetic woman presented with an exposed PC-IOL in her left eye with a history of mechanical trauma. Slit-lamp examination revealed an extruded PC-IOL lied on the anterior surface of cornea. The IOL optic part was firmly attached to the anterior surface of cornea while the haptics pierced the corneal tissue to the ciliary sulcus, detectable by ultrasound biomicroscopy. Posterior chamber intraocular lens dislocation can have grave consequences, including corneal touch, corneal decompensation and melting leading to severe visual loss. The possible mechanism of extrusion was presumed to be a cheese wiring process after corneal melting, leading to an exposed IOL.