Journal of Ophthalmic and Optometric Sciences

Purpose:To determine the effect of induced myopia and hyperopia in emmetropic eyes using soft contact lenses on retinal parameters, measured by optical coherence tomography.

Patients and Methods: In this quasi-experimental self-controlled study 57 emmetropic participants, 18 - 42 years of age, were studied. Each subject underwent a complete ophthalmic examinations including, measurement of best corrected visual acuity, intraocular pressure, dry and cycloplegic refractions, and axial length. Optical coherence tomography scans to measure foveal thickness, parafoveal thickness and perifoveal thickness were performed while different refraction powers were induced in each eye by wearing soft contact lenses of five different diopter (- 10.00, - 5.00, plano, + 5.00, + 10.00).

Results: Fifty seven normal emmetropic participants with a mean age of 25.78 ± 6.50 years participated in the present study. Average foveal thickness was 246.02 ± 22.03 μm, 245.47 ± 22.78 μm, 246.47 ± 24.38 μm, 246.42 ± 22.96 μm, and 246.18 ± 22.46 μm in high-induced- myopic (CL: + 10.00 D), mild-induced-myopic (CL: + 5.00 D), emmetropic (CL: Plano), mild-induced-hyperopic (CL: - 5.00 D), and high-induced-hyperopic (CL: - 10.00 D) groups, respectively. Average parafoveal thickness was 329.21 ± 16.31 μm, 329.24 ± 16.36 μm, 328.86 ± 16.46 μm, 328.92 ± 16.57 μm, and 328.80 ± 16.76 μm in high-induced-myopic, mild-induced-myopic, emmetropic, mild-induced-hyperopic, and high-induced-hyperopic groups, respectively. Corresponding numbers for perifoveal thickness was 312.25 ± 14.39 μm, 311.84 ± 14.91 μm, 312.46 ± 16.55 μm, 311.57 ± 14.88 μm, and 311.77 ± 14.96 μm. 

Conclusion: Contact lens induced myopia and hyperopia had no significant effect on foveal thickness,parafovealthickness and perifoveal thickness readings in Fourier domain optical coherence tomography.

Keywords: Optical coherence tomography; myopia; hyperopia; retinal parameters; contact lens. 

Purpose: To study clear lens extraction and posterior chamber intraocular lens implantation outcomes and safety in correction of high myopia.

Patients and Methods: Medical records of 29 patients (40 eyes) who underwent clear lens extraction with posterior chamber IOL implantation to treat high myopia (Axial length > 26.6) were retrospectively reviewed. Visual acuity and refractive error were assessed before and after surgery, and preoperative, intraoperative, and postoperative complications were also recorded.

Results: The mean postoperative follow-up period was 10.9 ± 4.63 months (Range, 6 - 19 months). The mean final best corrected visual acuity of 6/10 ± 2/10, was better than preoperative best corrected visual acuity (Mean: 2/10 ± 1/10). Final spherical equivalent (SE), (Mean = - 0.95 ± 0.45 diopters, Range - 0.25 to - 2 D) was better than preoperative SE (Mean = 19.41 D ± 5.31, Range 9 to 31 diopters). No cases of intraoperative complications occurred. The only postoperative complication was posterior capsule opacification in one eye 18 months after surgery and biometric error of (2 D) occurred in one eye. 

Conclusion: Clear lens extraction with posterior chamber IOL implantation in high myopic eyes has good outcomes with acceptable predictability, improvement in best corrected visual acuity and low rate of complications.

Keywords: Intraocular lens; extraction; posterior chamber; myopia; Iran.

Purpose:To evaluate refractive results after laser in situ keratomileusis among patients with thin corneas.

Patients and Methods: Three hundred and two eyes from 168 patients with thin corneas undergoing laser in situ keratomileusis in Basir Eye Clinic, Tehran, Iran, were retrospectively studied. We included patients with best corrected visual acuity of better than 6/12, age of more than 18 years, and corneal thickness of less than 499 μm.

Results: The mean age of patients was 30.7 ± 8.6 years and the mean preoperative spherical equivalent was - 4.61 ± 2.37 D. The results after at least one year of follow-up were as follow: 86.6 % of patients with low myopia, 71.8 % of patients with mild myopia, 50.0 % of patients with moderate myopia and 51.8 % of patients with high myopia achieved a ± 0.5 D spherical equivalent postoperatively. General linear model indicated a significant effect for the remaining stromal bed on final uncorrected visual acuity after adjustment for age, sex, and degree of myopia. No important complication occurred.

Conclusion: No important complications occurred after laser in situ keratomileusis among myopic patients with corneal thickness of less than 499 μm, and most of the patients achieved satisfactory refractive results.

Keywords: Laser in Situ Keratomileusis; outcome; myopia; thin cornea; Iran.

Purpose: To study post operative regression rates after photorefractive keratectomy among patients with hyperopia and hyperopic astigmatism with follow-up of at least six months.

Patients and Methods: In this historical cohort study, 171 eyes from 91 patients with moderate hyperopia and hyperopic astigmatism were treated using Bausch and Lomb Technolas 217 Z Excimer Laser. Pre-operation evaluation included; best spectacle corrected visual acuity, manifest and cycloplegic refraction, diameter of optical zone, central corneal thickness and simulated keratometry. Postoperative evaluation, performed at least six months after the procedure, included measurement of corneal curvature, manifest and cycloplegic refraction, best corrected visual acuity, uncorrected visual acuity, refraction manifest, haze, and any pathologic finding.

Results: The mean regression was 0.35 ± 1.04. Post surgical manifest refraction equivalent in ± 0.5 diopter range of surgeon’s desired refraction was observed in 57.1 % of eyes. Manifest refraction equivalent in ± 1.00 diopter range was observed in 85.7 % of eyes, and manifest refraction equivalent in ± 2.00 diopter range in 96.6% of eyes. Uncorrected visual acuity of 20/20 or better was reported in 37.1 % and 20/40 or better in 92 % of patients. Loss of the best spectacle corrected visual acuity of one line was observed in 13.4 % and 2 lines or more in 5.7 % of patients.

Conclusion: In patients with moderate hyperopia and hyperopic astigmatism undergoing PRK the rate of regression was in ± 1 diopter range of surgeon’s intended correction in 85.7 % of patients at least six months postoperatively, which is in line with other studies findings.

Keywords: Photorefractive keratectomy; Hyperopia astigmatism; Regression.

Purpose: To examine the causes of vision impairment and blindness
in a referral medical center in Tehran, Iran.
Patients and Methods:  The present cross-sectional study was conducted on visually impaired and legally blind patients in optometric
clinic of Rasoul-e-Akram hospital, Tehran, Iran, in 2015. We used the WHO criteria to evaluate visual impairment. The visual acuity of patients was recorded in a mono-eye fashion (right eye first then the left eye) using a 6-meter Snellen chart. The refractive error was evaluated and the best corrected visual acuity (BCVA) was recorded. Patients were then referred to ophthalmology department to diagnose the main cause of reduced vision.
Results:  This study included 77 legally blind or visually impaired patients. After examining the underlying causes of visual impairment, we found that 41.17 % of visual impairment among patients was caused by cataracts and 29.41 % was caused by retinal diseases. Corneal pathology, glaucoma and other diseases were the rarer causes of low vision among subjects. The causes of legal blindness were different; retinal diseases were the main causes of legal blindness (46.51 %) followed by cataract (30.23 %) and corneal pathology (13.95 %).
Conclusion:  Our results from a referral hospital in Tehran indicates that retinal pathology was the most common cause of legal blindness among our patients, while the most common cause of visual impairment was cataract. Due to the natural differences of epidemiologic findings gathered from a referral center and the community, multicenter studies are recommended to better evaluate the causes of visual impairment in our community.

Keywords: Visual; Impairment; Legal; Blindness; Iran.

Purpose:  The aim of this manuscript was to report the clinical characteristics of two patients suffering from acute acquired comitant esotropia presented in adulthood.

Case report: Both patients reported intermittent diplopia especially during car driving before their diplopia becoming constant. They had 20/20 uncorrected visual acuity and a cyclorefraction of + 0.50 D with normal extraocular function except very mild lateral rectus underaction (< 1) in their both eyes. In alternate prism cover test, the manifest esotropia of 25 - 30 Δ was measured at both far and near distances. They did not show any signs of neurological disorders such as marked extraocular underaction or different esotropia on lateral gazes compared with esotropia in primary position. No abnormality was found on electromyography, visual field measurements and magnetic resonance imaging for both cases.
Conclusion: Based on our clinical assessment, hereditary causes, mild lateral rectus underaction or inability to compensate esotropia due to decreased divergence amplitude and fusion could be considered as the probable risk factors for acute acquired comitant esotropia in adults, although the actual etiology of this disease has not been determined.

Keywords: Acquired; Esotropia; Acute; Etiology; Adult; Risk factor.

Purpose: The aim of the present study was to describe a case of
orbital fibrous dysplasia in a very young child.
Case report: A 5-year-old girl presented with unilateral, painless,
slowly progressive proptosis of the left eye and inferotemporal
globe displacement from about 1 year ago. The visual acuity in
both eyes was 20/20. The general physical examination was normal.
Computed tomography (CT scan) revealed thickening and deformity
of the orbital walls. Lateral orbitotomy and biopsy were performed
and were compatible with fibrous dysplasia.
Conclusion:   Craniofacial fibrous dysplasia usually occurs in the
second decade of life, but it can also rarely present in the early
years of life. Therefore, fibrous dysplasia should be considered as
a differential diagnosis of proptosis or globe displacement in the
early years of life.

Keywords: Fibrous; Dysplasia; Orbit; Child; Iran.

Purpose: To describe a case of choroidal melanoma with phacomorphic
glaucoma as the first presentation.
Case report: A 63-year-old woman was presented with painful
visual loss of the left eye. Mature cataract, flat anterior chamber and
elevated intraocular pressure were noticed in clinical examination.
B mode ultrasonography and CT-Scan showed a large intraocular
mass. Enucleation was performed and pathological analysis was
compatible with uveal melanoma.
Conclusion: The presence of mature cataract obscures the fundus
view in patients with phacomorphic glaucoma. Complete ultrasonographic
examination or other appropriate imaging techniques should
be performed to detect potential posterior segment pathologies like a
malignant melanoma among these patients.

Keywords: Phacomorphic; Glaucoma; Uveal; Melanoma.