BINA
Year:2008 | Volume:13 | Issue:2 (51)|Papers Count:20

Purpose: To determine the prevalence and characteristics of retinopathy in diabetic residents of Tehran province, Iran during 2005.Methods: This cross-sectional study was performed on 700 diabetic subjects who were recognized in a sample of 7500 individuals in the "Risk Factor Evaluation for Non-Contagious Diseases" project in LR of Iran, 2005. All subjects were recalled to attend a predefined location for the study. All participants underwent systemic examination by an intemist and a comprehensive eye examination including dilated funduscopy by a vitreoretinal specialist.Results: Overall 634 diabetic subjects with mean age of 59.3±12.0 (range 18-78 years) were studied. Retinopathy was detected in 37.9% (95% confidence interval [CI],  34.1%-41.6%) including 72.9% (95% CI, 67.3%-78.5%) non-proliferative and 27.1% (95%CI, 21.5%-32.7%) proliferative diabetic retinopathy. The prevalence of bilateral blindness was 2.1% and 0.8% in diabetic patients with and without retinopathy, respectively (P<0.001). Logistic regression revealed that diabetic retinopathy is associated with male gender (P=0.022), increased disease duration (P<0.001), diabetes control regimen (P<0.001) and presence of diabetic nephropathy (P=0.003).Conclusion: Regarding the high prevalence of diabetic retinopathy and the associated visual impairment, regular screening of diabetic patients for early detection of proliferative retinopathy and timely laser photocoagulation is highly recommended.

Purpose: To determine the distribution of very low (up to -1 diopter), low (-1 to -3 D), moderate -3 to-6 D), high (-6 to -10 D), and very high (beyond -10 D) myopia in myopic patients referred to Eye Clinics of Yazd Medical University during 2004-2005.Methods: This cross-sectional study was performed on 482 myopic patients who underwent dry and cycloplegic refraction by retinoscopy as well as autorefractometry to determine the degree of myopia. Results: Patients included 270 female (56%) and 212 male (44%) subjects with mean age of 27.7±13.7 (range 2-83) years. The mode of age was between 20-30 years. Mean myopia was -3.24±3.16 D; the most frequent degree of myopia was low (44.2%) to moderate (33.1%). Positive family history was seen in 48.2% of the patients.Conclusion: The majority of myopic cases are in low and moderate groups and aged between 20-30 years. Positive familial history has important role in myopia prevalence and intensity.

Purpose: To compare Acrys of IQ and Akreos AO aspheric intraocular lenses (IOLs) in terms of spherical aberration and contrast sensitivity.Methods: Thirty-seven eyes of 37 patients undergoing phacoemulsification cataract surgery were randomized to implantation of Acrysof IQ or Akreos AO IOLs. Three months postoperatively, bestcorrected visual acuity (BCVA), spherical aberration (with 4 and 6 mm pupil diameters) and contrast sensitivity in photopic and mesopic conditions at spatial frequencies of 1, 2, 5, 10 and 20 cycles per degree (cpd) were determined.Result: Mean BCVA was 0.083±0.071 logMAR in the IQ group and 0.115±0.090 logMAR in the AO group (P=0.338). Spherical aberration with both 4 and 6 mm pupil diameters was lower in the IQ group as compared to the AO group (0.183±0.107 pm vs 0.285±0.087 pm, P<0.001 and 0.26±0.096 pm vs 0.329±0.083 pm, P=0.40, respectively). Contrast sensitivity was significantly higher in the IQ group at 1, 2 and 10 cpd under photopic and at 1, 10 and 20 cpd under mesopic conditions as compared to the AO group.Conclusions: The Acrys of IQ seems to have better visual outcomes in terms of spherical aberration and contrast sensitivity as compared to Akreos AO.

Purpose: To compare Tecnis Z9000 and Acrysof IQ aspheric intraocular lenses (IOLs) regarding spherical aberration and contrast sensitivity.Methods: Thirty-four eyes of 34 patients undergoing phacoemulsification cataract surgery were randomly assigned to implantation of Tecms or IQ IOLs. Three months postoperatively, best-corrected visual acuity (BCVA), spherical aberration (with 4 and 6 mm pupil diameters) and contrast sensitivity in 'photopic and mesopic conditions at spatial frequencies of 1, 2, 5, 10 and 20 cycles per degree (cpd) were determined.Results: Mean BCVA was 0.083±0.071 logMAR in the IQ group and 0.076±0.080 logMAR in the Tecnis group (P=0.338). Spherical aberration in the Tecnis group was smaller with pupil diameter of 4 mm (0.140±0.097pm vs 0.183±0.107pm, p= 0.609) but greater with pupil diameter of 6 mm (0.303±0.183pm vs 0.26±0.069 pm, P= 0.40) as compared to the IQ group. Contrast sensitivity was higher in the Tecnis group at 1, 2 and 5 cpd under photopic (not significant) and mesopic (P<0.001, P<0.08, P=0.2, respectively) conditions. Conversely, contrast sensitivity was higher in the IQ group at 10 and 20 cpd under photopic and mesopic conditions (not significant).Conclusion: Tecnis or IQ IOLs seem to be comparable in terms of spherical aberration and contrast sensitivity.

Purpose: To compare Orbscan II and ultrasonic pachymetry for measurement of central corneal thickness (CCT) in eyes scheduled for keratorefractive surgery.Methods: CCT was measured using Orbscan II and then by ultrasonic pachymetry in 100 eyes of 100 patients who were scheduled for excimer laser refractive surgery. Paired Hest was used for comparing the results.Results: Using an acoustic factor (AF) of 0.92 for measurements by Orbscan pachymetry, the difference between mean CCT measured by ultrasound (544.7±35.5 mm)and Orbscan (546.9±41.6 mm)was not statistically significant (P=0.14). The standard deviation of measurements was greater with Orbscan pachymetry but this was not statistically significant.Conclusion: CCT measurements are comparable between Orbscan II (applying an AF) and ultrasound pachymeter; however when CCT measured by Orbscan II is in the lower ranges, it is better to recheck it using ultrasound pachymetry.

Purpose: To evaluate the incidence of steroid-induced ocular hypertension (OHT) after myopic photorefractive keratectomy (PRK).Methods: Myopic PRK was performed on 506 eyes of 269 patients. Refractive error was between -1.00 and -5.00 diopters of sphere and less than 4 diopters of cylinder. Baseline intraocular pressure (IOP) before the operation and at different time intervals after the operation was measured using Goldman Applanation Tonometry. Corrected lOP more than 21 mmHg was considered as OHT.Results: OHT occurred in 40 (7.9%) eyes. lOP rise occurred after 2-3 weeks in 40% (mean IOP= 23.5±3 mmHg), 4-6 weeks in 50% (mean IOP= 25.06±4.2 mmHg) and 8-12 weeks in 10% (mean IOP= 28.98±3.12 mmHg). There was no correlation between IOP and preoperative spherical equivalent. IOP recovered to normal in all patients after discontinuation of topical steroid and using 0.5% timolol. Mean duration for normalization of IOP was 28.5±27.7 (range 7-108) days. There was no case of steroid-induced glaucoma. Conclusion: Topical steroids may cause OHT in patients undergoing PRK. Early detection of lOP rise and meticulous treatment with close follow-up are recommended. We suggest measuring IOP in post- PRK patients at least after 2 to 3 weeks of corticosteroid treatment initiation. 

Purpose: To determine the effect of intravitreal bevacizumab (lYB) on neovascular glaucoma (NVG)in terms of intraocular pressure (IOP), iris neovascularization (NVI) and best-corrected visual acuity (BCVA). Methods: In this randomized controlled trial, 26 eyes of 26 patients with NVG receiving conventional treatment were randomly allocated to three 2.5 mg IYB injections at 4-week intervals or a sham procedure (subconjunctival normal saline) at similar time intervals and in the same setting. Changes in IOP, extent of NVI and BCVA were compared between the two groups.Results: Overall, 14 eyes of 14 patients received IVB and 12 eyes of 12 subjects were allocated to the sham procedure and followed for a mean period of 5.9±1.4 months. The study arms were balanced regarding age, sex, cause of NVG, BCVA, IOP, and extent of NVI. The IVB group demonstrated significant reduction in mean lOP from a baseline value of 33.4±14.5 mmHg to 21.8±13.7 mmHg (P=0.007), 25.1±20.0 mmHg (P=0.058) and 23.9±18.7 mmHg (P=0.047) one, three and six months after intervention respectively. Mean NVI was also significantly reduced from a mean baseline value of 347±48° to 206±185° (P=0.01), 180±187° (P=0.004) and 180±180° (P=0.004) one, three and six months after intervention respectively. Mean IOP in the sham group was 32.3±14.3 mmHg prior to intervention and 34.9±15.2 mmHg (P=0.046), 35.2±10.7mmHg (P=0.29) and 32.2±7.3 mmHg (P=0.92) at one, three and six months after the injection respectively. Mean NVI in the sham group increased insignificantly from a baseline value of 270±138° to 277±130° (P=0.34), 300±117° (P=0.22) and 324±114° (P=0.34) one, three and six months after intervention respectively. No significant change in BCVA was observed within the study groups at any time interval.Conclusion: Intravitreal injections of bevacizumab seem to significantly reduce the extent of NVI and lOP in neovascular glaucoma, but may not affect visual acuity.

Purpose: To determine the association between Norrie disease (ND) gene mutations and advanced stages of retinopathy of prematurity (Rap) in premature neonates who were referred to Farabi Eye Hospital, Tehran, Iran during 2005-2007Methods: Fifty infants including 28 male and 22 female subjects with Rap stage 3 or worse were enrolled in this case series. All three exons of ND gene underwent polymerase chain reaction (PCR) with three primer pairs and direct sequencing to determine any mutation.Results: Mean birth weight was 1187.6±227.6 (range 580-2000) gram and mean gestational age was 28.6±2.1 (range 24-34) weeks. Thirty-eight patients had stage 3 Rap with plus disease, four patients had stage 4 Rap and eight patients had stage 5 Rap. A C15078A mutation was found in the second intron of 90% of the cases.Conclusion: C15078A mutation is in a non-translated region of the ND gene and has no effect on mRNA splicing; therefore the association between this ND gene mutation and advanced stages of ROP in Iranian neonates with Rap is not significant.

Purpose: To determine the anatomical location of the inferior oblique (IO) rtluscle and any possible correlation between IO overaction and IO muscle mass.Methods: In this interventional case series, eyes undergoing primary surgery for IO overaction underwent measurement of the distance between IO muscle borders from the limbus as well as muscle belly circumference, intraoperatively.Results: Overall, 78 eyes of 51 patients with mean age of 18.3±12.3 (range 1-48) years were evaluated. Mean distance between the anterior and posterior borders of the 10 from limbus were 16.3±1.8 and 20.7±1.9 mm, respectively. Average muscle circumference was 10.7±0.9 (range 9-13) mm. There was no significant correlation between IO overaction and muscle belly circumference.Conclusion: Although knowledge about the anatomical location and muscle belly circumference of the IO muscle is important during surgery, there is no correlation between IO overaction and IO muscle mass.

Purpose: To evaluate the efficacy of subtenon injection of Botulinum toxin A (Dysport) in acute 6th nerve palsy.Methods: This randomized clinical trial was performed on 28 patients with 6th nerve palsy of less than 3 months' duration without history of extraocular muscles abnormality. Ophthalmic examinations included visual acuity, degree of eye deviation, slit lamp biomicroscopy and funduscopy. Patients were randomly assigned to two groups: 14 subjects received subtenon injection of 20 IU Dysport over the medial rectus muscle and 14 subjects served as controls who were followed without any injection. All patients were followed for at least 6 months. Distance esotropia of less than 10 prism diopters (PD) was defined as recovery.Results: The two groups were comparable regarding age and duration of the disease. The most frequent risk factor (42.9%) was diabetes mellitus. Mean duration to achieve recovery was 12.5+6.8 days in the treatment group and 63.5+26.4 days in the control group (P<0.001). At final follow up, all patients in the treatment group and 13 patients (92.9%) in the control group recovered completely (P= 0.71). Conclusion: Subtenon injection of Botulinum toxin A for acute 6th nerve palsy effectively reduces recovery time.

Stem cells are present in all self-renewing tissues and have unique properties. The ocular surface is made up of two distinct types of epithelial cells, including conjunctival and the corneal epithelium. Limbal stem cell deficiency results in conjunctivalization of the cornea leading to corneal vascularization and appearance of goblet cells in the cornea. Two methods of corneal regeneration are currently used in this setting: (1) auto transplantation of cellular layers from existing tissue-specific stem cells. (2) Transplantation of ex vivo expanded stem cells on processed human amniotic membrane. A newer approach is also under investigation including induction of ocular surface tissues from embryonic stem cells. In this article, we describe stem cells, particularly limbal stem cells, different types of corneal epithelial cells, corneal epithelial cell markers at different stages, and current approaches to corneal epithelial regeneration as well as culturing of limbal stem cells on amniotic membrane as a substrate and finally transplantation of cultured corneal epithelium.

Modern computerized technology enables more complex visual stimuli and test procedures to be incorporated into conventional perimetry resulting in several developments in automated perimetry that have contributed to more efficient diagnosis and management of eye diseases. This review will cover a number of advances in automated perimetry including frequency doubling technology perimetry, short wavelength automated perimetry, flicker perimetry, high-pass resolution perimetry and rarebit perimetry. Test algorithms applied to perimetry such as zippy estimation of sequential thresholds, Swedish interactive thresholding algorithm, tendency-oriented perimetry and multi-sampling suprathreshold perimetry are also discussed.

Purpose: To present a case of herpes zoster ophthalmicus (HZO) with consequent posterior ischemic optic neuropathy (PION).Case Report: A 58-year-old woman with a history of HZO in her right eye which was under treatment presented with loss of vision to no light perception. On examination, positive relative afferent papillary defect was detected; however the optic disc was normal on ophthalmoscopy. After three months visual acuity improved to counting fingers at one meter, but the optic disc became atrophic. PION was diagnosed and regarding a positive PCR test for herpes zoster virus and the short time interval between the two presentations, we considered herpes zoster virus as the most probable cause of the optic neuropathy.Conclusion: Herpes zoster virus can be considered as a cause of PION.

Purpose: To report the clinico-pathological and ultrastructural features of a case of Meesmann corneal dystrophy (MCD).Case Report: A 10-year-old boy presented with decreased vision in both eyes since early childhood. Slitlamp biomicroscopy disclosed diffuse intraepithelial microcystic changes in the cornea but other layers appeared unremarkable. High pathologic myopia and amblyopia were other abnormal clinical findings. The patient underwent automated lamellar therapeutic keratoplasty (ALTK) in the left eye with a probable clinical diagnosis of MCD. The corneal button underwent histopathologic and transmission electron microscopic examinations. Histopathologic examination disclosed abnormal appearing corneal epithelium with intracytoplasmic cyst-like inclusions and cellular swelling. The cells contained moderate amounts of PAS-positive and diastase-sensitive material consistent with glycogen. On transmission electron microscopy, numerous vacuoles of variable size were present within the cytoplasm throughout the entire epithelium. Moderate numbers of intracytoplasmic electron-dense and membrane- bound bodies similar to lysosomes were also noted, some engulfed by the vacuoles. Visual acuity in left eye was slightly improved postoperatively, but intraepithelial microcystic changes recurred after one year.Conclusion: To our knowledge, this is the first report of Meesmann corneal dystrophy from Iran describing the typical clinico-pathologic and ultrastructural features of this recurrent condition.

Purpose: To report the confocal scan features in a case with clinical diagnosis of Meesmann corneal dystrophy (MCD).Case Report: A 17-year-old female with recurrent episodes of corneal erosion and a clinical diagnosis of MCD underwent in vivo confocal scanning of both corneas. The confocal scan features included hyporeflective round-shaped areas measuring 6.8 to 41.4 mm with in the superficial epithelium, diffuse hyperreflective spots in the basal epithelium and high contrast but ill-defined irregular areas at the sub basal epithelial region. Except for the subepithelial nervus plexus which was not apparent because of the sub epithelial hyper reflectivity, other corneal layers looked unremarkable.Conclusion: Confocal scan is a non-invasive in vivo imaging method which should be considered as a valuable diagnostic adjunct in delineating the microstructural features of Meesmann corneal dystrophy.