BINA
Year:2011 | Volume:16 | Issue:4 (65)|Papers Count:15

Purpose: To compare aspheric and spherical hydrophilic intraocular lenses (IOLs) in terms of contrast sensitivity and visual acuity in photopic and mesopic conditions.Methods: This triple-blind randomized clinical trial was performed on 40 eyes of 40 patients at Al-Zahra Eye Center, Zahedan, Iran. The eyes were randomized to standard phacoemulsification procedure with spherical (Adapt, B& L) or aspherical (Adapt AO, B& L) IOLs. All operation were performed using the Alcon Infinity system by one surgeon and the IOL was placed within the capsular bag. Two months postoperatively, best corrected visual acuity (BCVA) in mesopic condition with brightness value of 8cd/m 2 as well as contrast sensitivity with BCVA in mesopic and photopic conditions with and without glare of 3cd/m 2 were determined using the Metrovision Monelci Contrast Sensitivity Device (53.8lux).Quality of vision was compared between the two groups by comparing average contrast sensitivity at frequencies of 0.5, 1, 2, 5, 10 and 20 cycle per degree using t-test.Results: There was no statistically significant difference between the study groups regarding BCVA or contrast sensitivity at different frequencies under photopic or mesopic conditions with pupil diameter of 5mm, and under photopic or mesopic conditions with glare.Conclusion: Considering the risk of visual loss due to IOL decentration. Besides contrast sensitivity, other factors such as price and ease of insertion and access should be considered for determining the IOL of choice in cataract surgery.

Purpose: To evaluate the effect of age on stereopsis.Methods: We evaluated stereoacuity using TNO and titmus test after full correction of refractive errors in 87 randomly selected subjects aged 5-80 years.Results: There was a significant relashionship between stereopsis and age such that stereoacuity increased with aging (ANOVA, P<0.001).Conculsion: Stereopsis decreases with aging and therefore age of the patient should be considered in this regard.

Purpose: To evaluate the effect of childhood corneal opacity on the anteroposterior length of the globe in adulthood.Methods: Twenty-three patients with significant unilateral corneal opacity which had developed before the age of 6 years and the normal fellow eyes (controls) were evaluated. A comprehensive ocular examination including measurement of anterioposterior length and anterior chamber depth was performed.Results: Mean age was 65.9±12.9 years. Mean axial length was 25.45±2.47 mm in affected eyes vs 22.85±3.34 mm in normal fellow eyes (P=0.001). The difference in axial length was attributed to elongation of the vitreous cavity in affected eyes (18.91±2.82 vs 15.71±2.73 mm, P<0.001).Conclusion: Corneal opacity in childhood can result in axial myopia in adulthood due to elongation of the posterior segment.

Purpose: To investigate indications and methods of surgery in corneal transplantation in Labbafinejad medical center from 2007 to 2009.Methods: Records of 1083 patients who had undergone corneal transplantation from 2007 to 2009 were reviewed. Age, sex and indication and type of surgery were evaluated.Results: Patients included 709 (65.5%) male and 374 (34.5%) female subjects with mean age of 43.2±10.2 year (range, 17 days to 33 years) keratoconus (36.7%) was the most common indication followed by cataract extraction with or without IOL insertion (12.8%); corneal ulcers due to bacterial, fungal and acanthamoba infections (11.7%); non herpetic scar and opacities (7.4%); trachoma keratopathy (5.6%); corneal dystrophy (4.6%) and mustard gas keratopathy (4%). The most common type of surgery was penetrating keratoplasty (56.2%) followed by deep anterior lamellar keratoplasty (24.5), tectonic grafts (9.4%), lamellar keratoplasty (3.4%), endothelial graft (3.5%) and keratolimbal allograft without penetrating keratoplasty (3.1%).Conclusion: During this 3 years period, keratoconus was still the most common indication for corneal transplantation but rate of regraft is increasing in comparison with previous reports. Corneal edema following cataract surgery with or without intraocular lens implantation was the second most common indication. Rate of endothelial grafts and keratolimbal alografts have increased since our previous reports.

Purpose: To evaluate the epidemiology of orbital and preseptal cellulitis in patients admitted to Labbafinejed Medical Center from 1997 to 2007.Methods: Hospital records of patients were reviewed. Personal and clinical characteristics of the patients together with results of treatment and complications of the disease were evaluated.Results: During the study period, 93 patients including 54 cases of preseptal cellulits were admitted. Male to female ratio was 2 for orbital cellulitis and 1 for preseptal cellulitis. Mean age was 27.4±23.9 years (range, 6 months to 98 years) in patients with orbital cellulitis and 19.1±23.3 years (range, 1 month to 82 years) in patients with preseptal cellulitis. Most of the cases (97.8%) were unilateral. Mean time from onset to referral was 4 days. Mean duration of hospitalization was 6 days for orbital cellulitis and 4.5 days for preseptal cellulitis. Most cases occurred during spring. The most common underlying disease was sinusitis which was present in 53.8% of cases of orbital sinusitis and 24.1% of cases of preseptal cellulitis with the ethmoid sinus being the most common involved sinus. An overage of 2 antibiotics were used for treatment. Surgical intervention was required in 48.7% of orbital and 14.8% of preseptal cellulitis cases. Extraocular muscle palsy occurred in one case as the only complication leading to surgical management.Conclusion: Orbital and preseptal cellulitis are seen most frequently in young patients in spring and sinusitis is the most common underlying disease. Timely treatment of sinusitis may prevent orbital and preseptal cellulitis.

Purpose: To measure the upper eyelid crease landmarks in an Iranian population sample.Methods: We studied 208 Iranian subjects aged 30 to 50 years. Upper eyelid crease height was measured in lateral, medial and central positions using Calipers. Levator function (LF) was also evaluated after exclusion of frontalis muscle function.Results: Mean age was 39.1±5.9 years and female to male ratio was 2.25. Overall mean LF was 15.70±1.77 mm (15.56±1.69 mm in female and 16.02±1.88 mm in male subjects). Overall mean lid margin medial crease distance (LMMC) was 3.84±1 mm (3.71±0.94 mm in female and 4.15±1.06 mm in male subjects); mean lid margin central crease distance (LMCC) was 7.57±1.54 mm (7.47±1.49 mm in female and 7.80±1.63 mm in male subjects) and mean lid margin lateral crease distance (LMLC) was 3.89±1.02 mm (3.82±1.03 mm in female and 4.04±1.01 mm in male subjects). There was no significant difference between men and women regarding LF, LMCC, LMLC and double crease however, LMMC was significantly greater in male subjects.Conclusion: Defining a normal range for upper eye lid crease dimensions in various races and different genders is helpful for cosmetic eyelid surgery.

Purpose: To compare the effect of different deviation measurement techniques and different lens powers on gradient accommodative convergence to accommodation (AC/A) ratio.Methods: We randomly selected 78 eligible students of different majors from Zahedan University of Medical Sciences. Following retinoscopy for refractive errors, alternate prism cover test, von Graefe and Maddox rod without additional lenses and with ±1, ±2 and ±3 D lenses were performed for measurement of deviation at near and determination of gradient AC/A Ratio. Data were analyzed using within subject factorial repeated measurement ANOVA and correlation tests.Results: Mean AC/A ratio was 3.6, 3.7 and 4 prism diopter to diopter using alternate cover test, Maddox rod and von Graefe methods, respectively (P=0.2). The highest and lowest AC/A ratios were related to von Graefe method with+3D and cover test with -1D lens power, respectively. Only differences between AC/A ratios with -1 and+2 lenses as well as with -1 and+3D were significant (P<0.05). For all different deviation measurement methods, AC/A ratios with plus lenses were higher than minus lenses.Conclusions: The type of deviation measurement method had no effect on AC/A ratio but selected lens power affected the results. We recommend using 2 or 3 diopter instead of 1 diopter lenses to avoid possible effects of depth of focus.

Purpose: To compare corneal hysteresis and resistance factor after penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK) using Anwar’s big-bubble technique using the ocular response analyzer.Methods: Forty-five PK eyes and 23 DALK eyes with keratoconus were compared in terms of corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann-correlated intraocular pressure (IOPg) and cornea-compensated IOP (IOPcc).Results: Mean age was 29.8±6.1 years in the PK group and 27.2±6.5 years in the DALK group (P=0.11); patients were followed for 31.4±19.0 and 29.2±17.3 months after corneal transplantation, respectively (P=0.27). There was no significant difference between the study groups in terms of recipient (P=0.21) and donor (P=0.57) trephine size or BSCVA (P=0.77). Mean CH was 10.09±2.5 mmHg in the PK group and 9.64±2.1 mmHg in the DALK group (P=0.36); mean CRF was 10.13±2.2 and 9.36±2.1 mmHg, respectively (P=0.17). No significant difference was found between the study groups in terms of IOPg (P=0.25) and IOPcc (P=0.80).Conclusion: PK and DALK techniques provide comparable graft biomechanics in keratoconic eyes.

Purpose: To compare the optical properties of hydrophilic and hydrophobic intraocular lenses (IOLs) containing UV-absorber and to determine their chemical composition.Methods: Optical properties of different foldable hydrophilic and hydrophobic as well as non-foldable hydrophobic polymethylmetacrylate (PMMA) IOLs were evaluated in three powers of 15, 22 and 25 diopters. Optical properties were measured using UV-VIS (UV-Visible) spectroscopy between wavelengths 200 and 800 nm and chemical structure characteristics were determined by ATR (attenuated total reflectance) spectroscopy.Results: ATR spectroscopy revealed that foldable hydrophilic and hydrophobic IOLs and non-foldable hydrophobic IOLs were respectively composed of hydroxyethylmethacrylate, a copolymer of phenylethylacrylate and phenylethylmethacrylate, and PMMA (in accordance with manufacturer’s claim).Cut-off points of the lenses were found to be around 350-420 nm. Increasing the IOL power from 15 to 22 diopters did not significantly change the cut-off points of foldable hydrophobic IOLs, however a considerable cut-off shift to higher wavelengths was noted when power increased to 25 diopters. PMMA lenses showed a constant cut-off at 400 nm for all power values.Conclusion: The increase in power is associated with absorption of lower energy UV radiation and shift of cut-off points to higher wavelengths in hydrophobic IOLs but with no considerable effect on cut-off points in PMMA IOLs.

Intravitreal injection is the most common approach for drug delivery to the posterior segment in humans.However, following the injection, drugs are rapidly eliminated from the vitreous, with half-lives up to a few days. Depending on the rate of clearance from the vitreous, large boluses and frequent administrations may be required to ensure therapeutic levels over an extended period of time. Multiple intraocular injections can lead to an increased likelihood of complications, such as vitreous hemorrhage, retinal detachment, endophthalmitis and cataract. In order to decrease the occurrence of complications associated with intravitreal injections, sustained-release drug delivery systems are desired to provide drug release into the posterior segment for a longer period of time (months or even years) compared to direct injection. This article reviews the current status of various intravitreal implants, both approved and in clinical development. These implants are: Vitraset, Retisert, Ozurdex (Posurdex), I-vation, Iluvien (Medidur) and NT-501. A search of the English language PubMed database was conducted with keywords of “intraocular implant”, “intravitreal implant”, “sustained-release” and “intravitreal drug delivery”.

Purpose: To introduce a case of neglected advanced retinoblastoma.Case report: A 6 year old girl presented with a large orbital mass enlarging over her cheek on the right side.She underwent exenteration and histopathologic evaluation. A diagnosis of retinoblastoma was made with free margins. This case presents a rare form of retinoblastoma with extensive local progression but no metastasis or CNS involvement.Conclusion: Although most of the retinoblastoma cases are diagnosed before the age of 3 years, there are neglected cases who present at advanced stages.

Purpose: To report a case of acute retinal necrosis following herpetic encephalitis.Case Report: A 25-year-old male presented with pain and visual loss in his left eye. He had herpetic encephalitis 1 month prior to the visual symptoms. Ophthalmologic examination and paraclinical evaluation disclosed acute retinal necrosis.Conclusion: Herpetic encephalitis may be a risk factor for acute retinal necrosis. The virus may reach the eye by transaxonal route.

Purpose: To report a case of free floating pyogenic granuloma within the lacrimal sac.Case Report: A 13 month old infant with unresolving dacryocystitis and history of two times failed probing and once failed turbinate fracture was scheduled for dacryocystorhinostomy (DCR). A free floating red mass was removed from the sac. Histopathologic examination confirmed a diagnosis of pyogenic granuloma.Eight months after the operation the patient was asymptomatic.Conclusion: When probing of the lacrimal duct fails to improve its obstruction, in addition to nasal lesions, lacrimal sac masses including pyogenic granuloma must be considered.