مجله چشم پزشکی بینا
سال نوزدهم شماره 4 (تابستان 1393)

To study the validity and reliability of subjective refraction, predicted phoropter refraction (PPR) measured by Zywave aberrometer, and final surgical plan applied for laser vision correction. This prospective study was conducted on 94 myopic or myopic astigmatic eyes (48 patients) who were candidates for refractive surgery in Negah Eye Hospital from April 2012 to July 201. Subjective refraction and PPR by Zywave aberrometry were measured and complete ophthalmic examination were performed in all participants. Surgical correction of refractive error was then planned, based on the subjective refraction and the patient’s age. The patient underwent customized surface ablation using the Bausch & Lomb 217 z excimer machine. At 6 months postoperatively, subjective refraction was measured to determine residual refraction. The “exact refraction” was defined as the refraction used for surgery added by postoperative residual refraction. This “exact” amount was compared with the preoperative subjective refraction, PPR and surgical plan. The mean difference between “exact” myopia and subjective refraction, PPR, and surgical plan were 0.110.51D (P=0.03), 0.18±0.70D (P=0.01), and -0.060.46D (P=0.01), respectively. The difference between “exact” myopia and myopia in subjective refraction and PPR was significant. The mean difference between “exact” astigmatism and astigmatism in subjective refraction, PPR and surgical plan were statistically significant (P<0.05). The lowest difference was between “exact” astigmatism and PPR astigmatism. (P=0.021). The correlation coefficient between “exact” myopia and subjective, PPR, and surgical plan myopia were 0.95, 0.92 and 0.96, respectively. Also, the correlation coefficient between “exact” astigmatism, subjective, PPR and astigmatism in plan were 0.89, 0.83 and 0.90 respectively. As indicated, the strongest correlation was observed between excat myopia and astigmatism, and PRP myopia and astigmatism. The mean myopia measured by Zywave aberrometer was comparable with exact myopia. Planning the myopic refractive correction based on the patient’s subjective refraction and adjusted by age was the most accurate method to achieve the least amount of residual refraction. There was no significant difference between exact astigmatism and preoperative astigmatism measured by the three methods.

To compare the results of three-piece and one- piece hydrophobic acrylic posterior chamber intraocular lens (IOL) with poly methyl metacrylate (PMMA) IOL implanted during lensectomy, posterior capsulotomy and anterior vitrectomy for congenital or developmental cataract. This is a historical cohort study conducted on patients with congenital or developmental cataract who underwent lensectomy, posterior capsulotomy and anterior vitrectomy between 1992 and 2012. Main outcomes were best-corrected visual acuity, early and final astigmatism, and postoperative complications including uveitis and visual axis opacification. A total of 67 eyes of 39 patients were included in the study. PMMA, three-piece (Alcon MA60 - AC) and one-piece (Alcon SA60 – AT) IOLs were implanted in 27, 22 and 18 eyes, respectively. The mean followup period was 101±49, 74±55 and 38±42 months, respectively. Best-corrected visual acuity was not significantly different among groups (P=0.823). Although early postoperative astigmatism was higher in the PMMA group, there was no significant difference among the study groups in the long term follow-up. The rate of postoperative uveitis, visual axis opacification and a need for laser capsulotomy was comparable in all groups. Although in-the-bag foldable acrylic IOL implantation is preferred during lensectomy, posterior capsulotomy, and anterior vitrectomy for congenital or developmental cataract, PMMA posterior chamber intraocular lenses can still be a safe and acceptable alternative, especially when sulcus fixation of the intraocular lens is scheduled.

To evaluate the safety, efficacy, stability and predictability of posterior chamber collagen copolymer phakic intraocular lens (PIOL) implantation to correct myopia and myopic astigmatism in keratoconusaffected patients. Uncorrected (UCVA) and best-corrected (BCVA) distance visual acuity, refraction and complications were evaluated in 22 keratoconic eyes of 14 patients who underwent Implantable Collamer Lens (ICL) (STAAR Surgical Inc.) implantation. The outcomes were evaluated during a 6 month follow up. Mean preoperative spherical equivalent (SE) and cylinder decreased from 4.98±2.63 and -2.77±0.99 diopters (D) preoperatively to -0.33±0.51 and −1.23±0.65 D at the end of 6-month follow up, respectively. Preoperatively, the mean Snellen decimal BCVA was 0.63±0.20. The mean UCVA was 0.76±0.23 and BCVA was 0.85±0.21 at the final follow up. The mean safety and efficacy indices were 1.40±0.32 and 1.24±0.34, respectively. No line of BCVA was lost; 17 eyes (77.3%) gained 1 or more lines. Fifteen 68.2%) of the eyes were within±0.50 D and 20 (90.9%) were within±1.00 D of the desired spherical equivalent refraction. There was a change in manifest refraction of 0.09±0.21 (range, -0.25 to +0.75) from week 1 to month 6 postoperatively. Toric ICL was safe, effective, and predictable to correct myopia and myopic astigmatism associated with keratoconus. The achieved refraction remained stable during the course of the study.

To analyze the clinical patterns and etiologies of uveitis in Isfahan. The records of 2016 patients with uveitis who had been referred to the Feiz tertiary eye care center, Isfahan, between 1999 and 2013 were classified and analyzed with respect to demographic, clinical, anatomical, and etiological characteristics. At the onset of uveitis, the mean patient age was 33.76 years. Female to male ratio was 1.2/1.0. Anterior uveitis was the most common diagnosis (42.9%) followed by posterior uveitis 21.42%), intermediate uveitis (19.3%), and pan uveitis (16.31%) in descending order. Overall, non-infectious causes were more frequent etiology of uveitis (76.5%) as compared to infectious causes. Up to 43.89% of the patients had no identified etiologies. The most common known etiology was toxoplasmosis, followed by Behcet disease and Fuchs’ heterochromic iridocyclitis (FHIC). The most common etiology was idiopathic 50%) and FHIC (32.8%) in anterior uveitis, toxoplasmosis (91.1%) in posterior uveitis, idiopathic (81.5%) in intermediate uveitis, and Behcet disease (48%) and idiopathic (32%) in posterior uveitis. In 15.62% of cases, a systemic disease was diagnosed which included Behcet disease (the most common non-infectious systemic disease) and toxoplasmosis (the most common infectious systemic disease). Considering the course of uveitis, 49.6% were chronic. In 87.5%, uveitis was non-granulomatous. Significant differences were seen in the clinical and etiologic pattern of uveitis in Isfahan. For example, a higher frequency of uveitis caused by Toxoplasmosis, Behcet and FHI was observed. Environmental, genetic and geographical factors may contribute to this observed difference.

To determine refractive errors and ocular alignment in newborns and small infants and to investigate the relation among these parameters and the infant's age. A descriptive study using non-randomized sampling was conducted on 150 infants from a healthcare center in the south of Tehran. All infants who were younger than two months of age underwent Hirschberg test and cyclorefraction. The prevalence of hyperopia was 86%; 3.3% had myopia and 46.7% had astigmatism > 1.00 diopter. There was a significant difference between boys and girls in terms of astigmatism in the right eye and gestational age (P<0.05). Mean astigmatism was greater in the right eye in girls. The hyperopic shift was higher in our study as compared to studies performed in other countries. Our findings can be explained by other Iranian studies conducted on other age groups.

The 3T3 feeder layer cells are commonly used for stem cell maintenance and expansion. Although feeder free systems are recently being developed for embryonic stem cells culture, deciphering the ability of new sources of feeder cells is still important for accurate expansion of epithelial stem cells. This study was aimed to introduce a new feeder layer for the culture of human limbal stem cells which can be applied for therapeutic corneal regeneration. For this purpose, the potential of unrestricted somatic stem cells (USSCs) isolated from umbilical cord blood was investigated. Human limbal stem cells were co-cultured with mouse 3T3 fibroblasts in addition with human unrestricted somatic stem cell (USSC), isolated from full term-pregnant women. The expression of surface markers including CD73, CD90, CD105, CD45, CD34, and CD44was evaluated using flowcytometry. Lmbal stem cells were cultured on two feeder layers in which mitotic activities were inhibited using mitomycin C. The morphology of cultured cells was assessed using phase-contrast microscopy. Furthermore, stem cell characteristics were assessed using immunocytochemistry and real-time PCR for stem cell markers including p63, KRT19, KRT3, Cx43, vimentin, involucrin and ABCG2. Additionally, chromosomal karyotype analysis was preformed. Cord blood somatic stem cells with spindle-shaped morphology can be quickly split up. The results demonstrated that limbal stem cells cultured on USSC surface were positive for ABCG2, 63 and KRT19. These results were confirmed by real-time PCR analysis. Limbal stem cells grown on a USSC feeder layer maintained a stem cell-like phenotype, comparable to cells grown on a 3T3 feeder layer. Karyotype analysis of USSCs and Limbal stem cells represented a normal 44XX karyotype. USSC could successfully support the growth of human limbal stem cells even better than 3T3 feeder cells. Since USSC are derived from human beings, it has an advantage over 3T3.

To develop a fast algorithm for automatic accurate extraction of blood vessels from retinal images in order to facilitate image analysis and minimize the rate of diagnosis error. We proposed an efficient algorithm using adaptive filter and thresholding technique which are based on fuzzy entropy. The data included retinal images from 60 index normals and patients (including 38 men and 22 women) obtained from STARE and DRIVE databases. The mean subject age was 47.6±9.1 years. In images from index patients, the presence of abnormal tissue was confirmed by two specialists. Initially, image blurring caused by vibrations during image capturing was eliminated using designed Wiener filter. The impact of optical reflection in each image was minimized through transferring images into the HSV space and selecting the spatial mask for retina. Extraction of retinal blood vessels was done using adaptive filtering. Finally, to separate the main artery of the retina from the rest of the tissues, the optimal threshold was obtained which was defined by the fuzzy entropy technique. By using combined methods in pre-processing step of retinal images, the optic disc border and radiant reflections of ophthalmoscope disappeared in the output image. Therefore, the accuracy (0.9475±0.08) and F-measure (0.7426±0.05) increased significantly. Fast and accurate extraction of blood vessels in the retinal images enables the ophthalmologist to predict disease progression, hence suggesting appropriate treatment modality.

To evaluate color vision in patients with type II diabetes mellitus without diabetic retinopathy and compare the results with those of age- and sex- matched normal individuals. This descriptive, comparative study was conducted on 100 diabetic patients without any sign of retinopathy and 100 age- and sex-matched normal subjects. Color vision was evaluated using Ishihara and Farnsworth D-15 color vision tests. Farnsworth D-15 color test showed that 26% of diabetic patients and 3% of normal subjects had color vision defect. Using Ishihara test, 3% of the subjects in each group had color vision defect. D15 color test revealed a color vision defect in spite of the normal retinal appearance in diabetic patients. It means that functional changes may be detected with proper color vision test before any structural changes in retina. We recommend Farnsworth D-15 test for this purpose.

Majority of practical terms in ophthalmology were compiled firstly in Muslims` medical dictionary. Anatomical and pathological terms such as retina and cataract were improved in this lexicon. Mohammad Ghazi, in journal of Azziae, has considered ophthalmology as an innovation which was firstly introduced by Muslim Arabs. Their attempts promoted this science and retained it the best for a long time. The publications of these scientists had been taught at European universities as the final notions on ophthalmology till the beginning of the eighteenth century. They also had valuable discoveries in this regard. Razi, for the first time, explained pupillary light reflex and Pur Sina (Avicenna) by performing eye autopsy illustrated eye muscles and their function in The Canon of Medicine. Ibn al-Haytham`s broad knowledge of light rules and natural sciences, acquired from Muslim scientists, resulted in revolution and progress of preceding concepts and developed optic science. In this paper the history of ophthalmology in Islamic world is reviewed.