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سال پانزدهم شماره 3 (بهار 1389)

To assess Hoffer correction factor in measurement of axial length (AL) in eyes with phakic IOL implants. In this descriptive historical cohort study, axial length was measured by ultrasound (US) and IOL Master in both phakic and pseudophakic modes in 24 eyes of 14 patients with Artisan intraocular lenses (IOLs) implanted for refractive purposes, Hoffer’s suggested formula for correcting ultrasound AL was applied to the data (cor-US) and all four datasets were compared to preoperative ultrasound AL values as standards. The mean difference between preoperative ultrasound measurements and postoperative readings by US (ALpo), IOLMaster in phakic mode (AL IOLMp), IOL Master in pesudophakic mode (AL IOLMpp) and US corrected with Hoffer factor (ALhc), were 0.01, 0.022, 0.13, and 0.61mm, with mean absolute differences of 0.23, 0.23, 0.26, and 0.25mm, respectively. In these readings, respectively 42.3%, 37.5%, 57.5%, and 46.2% of differences were greater than 0.2 mm, which is considered to be clinically important. Use of the Hoffer correction factor has no clinical application for a more accurate biometry in patients with an Artisan implant. The most reliable method in this type of patients is making an accurate record of their preoperative AL measured with ultrasound or IOL Master.

To investigate the outcomes of keratolimbal allograft (KLAL) for treatment of total limbal stem cell deficiency (LSCD). Patients with total LSCD and adequate tear production were included. A total of 27 KLAL procedures were performed in 21 eyes of 20 patients with LSCD. Immunosuppression was achived using mycophenolate and cyclosporine. Main outcome measure was improvement in vision; in addition, KLAL survival and post operative complications were studied. Mean follow up period was 22.14±11.83 months (range 6-39). Mean visual acuity improved from 2.53± 0.21 to 1.49±0.77 LogMAR (P<0.0001). Six KLALs never re-epithelialized and were considered as primary failures. Mean KLAL survival was 14.23±1.5 months. Graft survival rate was 61.9% at 1 year and 31% at 20 months. Complications included corneal ulcers in 6, glaucoma in 2 and scleral thining in 1 case. Keratolimbal allograft surgery is successful in the short term for visual rehabilitation of patients with total limbal stem cell deficiency.

To evaluate stem cell deficiency using impression cytology (IC) in patients with chronic and delayed-onset mustard gas keratopathy (MGK). A consecutive series of patients with MGK underwent IC. Thirty-five eyes of 18 patients (all male) with mustard gas keratopathy were included in this observational case series. Presence of goblet cells on the corneal side of specimens was considered to indicate stem cell deficiency. Corneal involvement was graded as mild, moderate and severe. Relation between IC findings and clinical grading was evaluated. There was limbal stem cell deficiency in at least one quadrant of the cornea in all 35 eyes (100% of cases). No differences was found between impression cytology findings (positive versus negative for corneal goblet cells) among different quadrants (p= 0.378). Clinical grading was the same between nasal and temporal quadrants (P=0.266) and between superior and inferior quadrants (P= 0.263). Combining the superior and inferior quadrants (vertical zone) and also the nasal and temporal quadrants (horizontal zone) together, clinical grading was more severe in horizontal versus vertical zones (p< 0.001). There was no correlation between stem cell deficiency and clinical corneal severity (p=0.893). Varying degrees of stem cell deficiency was demonstrated in all patients with chronic or delayed-onset MGK using IC. Clinical corneal manifestations are more severe in nasal and temporal quadrants. We found no correlation between stem cell deficiency and clinical manifestations. Other factors such as perilimbal conjunctival ischemia might play a role.

To evaluate the safety of different doses of intravitreal bevacizumab in rabbit eyes. Twelve eyes of 6 rabbits underwent intravitreal injection of 5, 7.5 and 10 mg of bevacizumab. In each rabbit, one eye was considered for bevacizumab injection and the fellow eye served for either placebo injection or observation. All eyes were examined before and 1, 2, 3, 7, 14 and 28 days after intravitreal injections. Electroretinography (ERG) was performed before and 14 days after the injections. 28 days after the injections, all eyes were enucleated and examined with light and electron microscopy. In the clinical examination, significant vitritis was observed in one of the 10 mg injected eyes from first post-injection which was eliminated by the 7th day. Cataract was seen in the same eye. Post-injection ERGs showed no significant changes. Increase in Muller-like cells was observed in the histological examination in the injected eyes. Intravitreal injection of 5 and 7.5 mg doses of bevacizumab was safe in rabbit eyes; however, the 10 mg dose was associated with intraocular inflammation.

To evaluate the complications of scleral perforation during strabismus surgery and the role of cryopexy, laser therapy, and conservative management in an animal model. In this experimental study, 42 pigmented-eye rabbits were included. An S-24 needle attached to a 6-0 polyglactin suture was passed through the sclera and into the vitreous cavity in both eyes of the animals. One eye of the rabbits received either laser therapy (n=20) or cryopexy (n=22) and the fellow eyes were left untreated (n=42). The incidence of complications was compared between the three groups. Cataracts developed in 7 (8.3%) eyes. Corneal opacity and transient localized sub-retinal fluid around the break were observed in one (1.2%) eye each. Other complications such as endophthalmitis and retinal detachment were not seen. There was no significant difference between the study groups in terms of complications. Vision-threatening complications following scleral perforation during strabismus surgery are uncommon and long-term follow-up is sufficient for management of this complication.

To compare visual outcomes and changes in high-order aberrations (HOAs) following conventional versus customized photorefractive keratectomy (PRK). In this clinical trial, 58 eyes of 29 patients underwent myopic PRK using the Technolas 217Z excimer machine. After comprehensive evaluation for refractive surgery, one eye of each participant randomly received conventional ablation (group 1) while customized treatment was performed in the fellow eye (group 2). Changes in postoperative visual acuity, cycloplegic refraction, and contrast sensitivity function (CSF), HOAs and subjective complaints of halos and glare were compared between the two groups. Mean subject age was 26.7±6.0 years. Mean preoperative cycloplegic spherical equivalent refractive error and refractive astigmatism were -4.92±1.6 D and 0.91±1.0 D, respectively. There was no significant difference between the two groups in terms of preoperative HOAs and CSF. Mean follow-up period was 8.1±3.3 months. After the operation, total HOAs for 4 mm pupil was increased by 0.24±0.19 µm in group 1 and by 0.31±0.21 µm in group 2 (P<0.001). Corresponding figures for 6 mm pupil were 0.34±0.23 (range -0.08 to 0.75) and 0.52±0.32 (-0.04 to 1.43) µm respectively (P=0.03). The increase in postoperative HOAs was statistically significant in group 2 in the 6 mm zone (P=0.03) but not in the 4 mm zone (P=0.26). CSF was reduced in both groups, but there was no significant difference between the study groups in terms of postoperative CSF and subjective complaints. HOAs significantly increased after PRK using conventional and customized ablation. The increase in HOAs after customized ablation was significantly greater than that after conventional ablation.

To determine the prevalence and risk factors for retinopathy of prematurity (ROP) in high risk premature infants admitted to NICU wards in Isfahan from 2003 to 2008. In this retrospective case series, 604 records of high risk infants were reviewed in terms of gestational age, birth weight, oxygen supplementation, delivery method, history of consanguineous marriage, single or multiple births and gender. The prevalence of ROP was 17.5%. In univariate analysis, birth weight (P<0.01), gestational age (P<0.01) and supplemental oxygen (P=0.01) showed statistical difference between neonates with and without ROP. In other words, lower birth weight, lower gestational age and supplemental oxygen were associated with ROP. The relationship between other variables and ROP was not statistically significant. The prevalence of ROP in this study emphasizes the importance of neonatal screening in our country. Low birth weight and gestational age were significant risk factors for the disease.

To report the confocal microscopic features of endothelial vacuolation in donated corneas and to confirm the observed changes by transmission electron microscopy. Confocal and transmission electron microscopy were performed on donated corneas with endothelial vacuole formation on slitlamp biomicroscopy. The ultrastructural findings were also compared with those of a normal-looking endothelium from a keratoconic cornea. Confocal microscopy revealed large numbers of dark round to oval-shaped structures within the endothelium, consistent with vacuolation which was confirmed by light and electron microscopy by the presence of variable-sized cyst-like structures within the endothelial cytoplasm mainly near the posterior cytoplasmic membrane in semithin preparations and observation of electron-lucent and relatively large-sized intracytoplasmic vacuoles on transmission electron microscopy. These features were not observed in the normal-looking endothelium of a keratoconic cornea. In this report, confocal microscopic features of endothelial cell vacuolation are presented in donated corneas and confirmed by transmission electron microscopy. The confocal microscopic images can serve as a useful reference image for endothelial vacuolation.

Optic neuritis occurs in young patients, most often females, and presents as subacute monocular visual loss. Periocular pain, particularly with eye movement occurs in the majority of cases. The retrobulbar form occurs in 65% of cases and is associated with normal optic disc appearance at onset. The central visual field is usually affected and an RAPD and dyschromatopsia are present. Brain magnetic resonance imaging (MRI) is recommended in all cases of optic neuritis. Evaluation for periventricular white matter lesions is the single best test for assessing the risk of future multiple sclerosis (MS). Typical idiopathic neuritis begins to show improvement within one month, the use of intravenous methylprednisolone 250 mg every 6 hours for 3 days, followed by oral prednisolone 1 mg/kg/day for 11 days speeds recovery by 1 to 2 weeks. Oral prednisolone alone has shown no benefit, has been associated with an increased risk of recurrence and its use is not recommended.

To report a patient with fundus flavimaculatus or macular dystrophy with flecks, who came to medical attention due to deteriorated vision in one eye and combined hamartoma of the retina and retinal pigment epithelium. A 26 year old lady was referred with history of progressive decreased vision in both eyes since childhood with recently deteriorated vision in her right eye. In the last examination, visual acuity with correction was 20/400 in the right and 20/200 in the left eye. On biomicroscopic funduscopy, there was a mass-like lesion extending all over the macula in the right eye with distortion of the fundus and retinal vasculature. A thick epiretinal fibrous membrane covered the lesion. Left eye examination revealed lack of foveal reflex with an atrophic retina, retinal pigment epithelium and choriocapillaris accompanied by pigmentary changes. Diffuse flecks extended from the macula to the mid periphery. Elecroretinogram and electrooculogram confimed a diagnosis of advanced fundus flavimaculatus. Fluorescein angiography and indocyanine green imaging did not show any evidence of choroidal neovascularization. There has been no report of concurrent macular dystrophy with flecks and combined hamartoma of the retina and retinal pigment epithelium in the literature. It is not clear whether this is an accidental association or there may be genetic footprints.