مجله چشم پزشکی بینا
سال هفدهم شماره 3 (بهار 1391)

To compare the efficacy of intravitreal clindamycin and dexamethasone with classic treatment for ocular toxoplasmosis.

In this prospective, randomized single-masked clinical trial a total of 68 patients with active ocular toxoplasmosis were assigned randomly to 2 treatment groups: 34 in the intravitreal clindamycin plus dexamethasone (IVCD) group and 34 in the classic treatment (CT) group. The IVCD group received 1 to 3 injection(s) of 1 mg intravitreal clindamycin and 400 g dexamethasone, and the CT group received 6 weeks of treatment with pyrimethamine and sulfadiazine plus prednisolone. Antitoxoplasmosis antibodies (immunoglobulin [Ig] M and IgG) were measured using an enzyme-linked immunosorbent assay.

The mean number of injections in the IVCD group was 1.6. Lesion size reduction was statistically significant after treatment in both IVCD and CT groups (P< 0.001 and P: 0.009, respectiveiy). The difference in mean percentage of reduction at 6 weeks was not significant: 5727.6% in the IVCD group versus 58.429.3% in the CT group. In comparison to baseline, VA increased by 0.440.24 and 0.290.19 logarithm of the minimum angle of resolution units in the IVCD and CT groups, respectively (P< 0.001); however, the difference in VA improvement between the groups was not significant. The interaction effect of IgM and treatment group on lesion size reduction was significant (P= 0.002); this indicated that IgM-positive cases responded better to CT and IgM-negative cases responded better to IVCD treatment. Vitreous inflammation reduction was comparable between the groups. Within 2 years, 4 eyes (2 in each group) had 1 episode of recurrence. Adverse drug reactions occurred in 2 patients in the CT group. No major injection-related complication was encountered in the IVCD group.

Intravitreal injection of clindamycin and dexamethasone may be an acceptable alternative to classic treatment in ocular toxoplasmosis. It may offer more convenience, a safer systemic profile, greater availability, and fewer follow-up visits and hematologic evaluations.

To report the outcomes of graft refractive surgery (GRS) together with clear-cornea phacoemulsification and intraocular lens (IOL) implantation in post-penetrating keratoplasty (PKP) eyes.

Fourteen eyes of 13 patients who had received PKP underwent simultaneous GRS (relaxing incisions with or without counter-quadrant compression sutures) and clear-cornea phacoemulsification with IOL implantation. To calculate IOL power, preoperative keratometry readings and the SRK-T formula were used.

Mean patient age and follow-up period were 50.5±14.4 years and 14.6±7.1 months, respectively. A significant increase was observed in best spectacle-corrected visual acuity (from 0.55±0.18 logMAR to 0.33±0.18 logMAR, P=0.001). There was a significant decrease in vector keratometric astigmatism by 6.22 D (P=0.03).Spherical equivalent refraction was reduced from −3.31±3.96 D to −1.69±2.38 D (P=0.02) which did not significantly differ from the target refraction (−0.76±0.14 D, P=0.20). No complications developed and all the grafts remained clear at the final examination.

Simultaneous phacoemulsification and GRS is a safe and effective method to address post-PKP astigmatism and lens opacity. IOL power can be calculated from preoperative keratometry readings with an acceptable accuracy. However, patients should be informed about the possibility of high refractive errors postoperatively.

To determine the outcomes of visual correction with femto-LASIK following PK.

In this prospective study, 34 eyes of 31 patient who had undergone thin – flap lasik due to high refractive error after corneal grafting were evaluated. After complete ocular examination and assessment of uncorrected and corrected distant visual acuity (UCVA and BCVA), the patients underwent femto-lasik using the Ziemer femto-LDV with 100 micron flap thickness.

After 3 to 19 (10.14±4.81) months of follow-up, mean UCVA increased from 1.5 Log MAR preoperatively (5/100) to 0.3 LogMAR (5/10) postoperatively (P<0.05). Mean BCVA also increased from 0.3 LogMAR (5/10) to 0.1 LogMAR (8/10) (P<0.05). Mean spherical equivalent changed from -6.98±3.87 to -2.18±2.69and mean of defocus equivalent also decreased from 10.32±3.74 preoperatively to 4.13±2.93 postoperatively (P<0.05 for both). No significant intraoperative and postoperative complications occurred.

Femto-LASIK surgery after penetrating keratoplasty is a successful procedure for correction of moderate to high refractive errors. It seems to be clinically safe, effective and predictable.

One of the major causes of visual acuity loss in diabetic patients is diabetic macular edema (DME). Best-corrected visual acuity and central macular thickness changes are considered as two main outcomes in diabetic macular patients. The goal of this study was to compare the effect of intravitreal bevacizumab injection alone or combined with triamcinolone versus macular photocoagulation as primary treatment for diabetic macular edema according to the clinical trial data sets.

A new method was proposed to determine the best treatment for DME; i.e. intravitreal bevacizumab injection alone or combined with triamcinolone versus macular photocoagulation using asymmetric mixed modeling based on the recorded data in 97 diabetic patients. Effect of these treatments was investigated according to simultaneous investigation of visual acuity and central macular thickness as two major outcomes without omitting any outlier.

The results of bivariate asymmetric mixed model revealed that intravitreal bevacizumab injection alone or combined with Triamcinolone treatments had more therapeutic effect than the macular photocoagulation in terms of increasing visual acuity and decreasing central macular thickness in patientswith DME.

Using asymmetric bivariate mixed model, there was a significant difference among the treatment modalities, duration of diabetes and gender in terms of visual acuity and central macular thickness.

To determine stereopsis with local (Titmus) and global (TNO) tests in symptomatic and asymptomatic subjects according to induced disparity (crossed or uncrossed).

In this cross sectional study, 80 students of Zahedan University of Medical Sciences who fulfilled the inclusion criteria were randomly selected. At first, refractive error was determined by retinoscopy and then based on the presence of binocular vision symptoms subjects were divided into symptomatic and asymptomatic. The ocular deviation was determined with use of the alternate prism cover test and stereopsiswas determined with TNO and Titmus tests. Data was analyzed in software SPSS.15 using Mann-Withney U, Wilcoxon, Spearman correlation and Fisher’s exact tests.

Mean stereopsis with the TNO test in symptomatic and asymptomatic subjects with crossed disparity was 133.12±70.11 and 76.78±82.57 sec/arc and that with uncrossed disparity was 135.0±67.5 and 83.2±49.7 sec/arc, respectively. Using the Titmus test with crossed disparity the value was 44.3±7.27 and 40.7±3.4 sec/arc and with uncrossed disparity stereopsis was 50.0±12.1 and 40.0±0.0 sec/arc in symptomatic and asymptomatic subjects, respectively. The Mann-Withney U test showed significant difference between stereopsis (with crossed and uncrossed disparity) with symptoms (P<0.05).

Stereopsis is a useful factor in differential diagnosis of individuals with symptomatic and asymptomatic binocular vision that for these purpose the local and global tests can be used, the importance of the global tests is more than local tests. There is no difference between crossed and uncrossed disparity stereopsis in all subjects.

To evaluate the effect of vertical prism induced stress on binocular visual evoked potentials.

Using checkerboard stimulus patterns in two spatial frequencies (SFs) of 0.48 cpd as a low SF and 2.18 cpd as a moderate SF reversing with temporal frequency of 4 Hz, the effect of increasing visual stress using vertical prisms of 0, 1, 2 and 3 prism diopters on binocular visual evoked potentials was investigated. The project was performed on 23 participants (11 male and 12 female) with normal binocular visual function, i.e., vertical prism vergences and stereo acuities were within normal limits. The amplitude and latency of N75, P100 and N135 components were measured during different vertical prism induced stresses in all cases. To compare mean amplitude and latency with different vertical prism induced stresses, the repeated measure ANOVA statistical method was used.

The amplitude of N75, P100 and N135 components showed reduction as a function of vertical prism induced stress at both low and moderate SFs (P<0.001). This reducing trend was more severe with increasing intensity of prism stress, while the latency of these components showed an increase as a function of vertical prism induced stress at both low and moderate SFs (P<0.001).

Based on clinical findings, ocular symptoms are caused by the vertical prism induced stress; in visual evoked potential as a paraclinical test, amplitude and latency of all components of the VEP wave, are affected by this stress.

To evaluate changes in graft steepness after graft refractive surgery (GRS) and to discover influential factors and a coefficient to predict the amount of postoperative shift.

Keratoconic patients with history of penetrating keratoplasty (PKP) who underwent GRS due to high post-PKP astigmatism were included. Changes in mean keratometry after GRS were evaluated to find possible influential factors such as age, graft anatomical features, number of incisions, use of compression sutures, and total arc length on achieved vector astigmatic correction.

There was a significant increase in average keratometry by 0.86±1.07 D postoperatively (P<0.001). Mean keratometric coupling ratio (CR) and coupling constant (CC) were 0.621.09 and -0.340.70, respectively. A significant association was found between preoperative spherical equivalent keratometry and keratometric CR, and between achieved correction in vector keratometric astigmatism and keratometric CC. Additionally, age had a significant negative association with keratometric CR and CC.

A significant increase in graft steepening occurred after GRS. For every diopter reduction in vector keratometric astigmatism, a mean of 0.34 D increase in graft curvature is expected postoperatively.

To compare visual outcomes and surgical complications of three phakic intraocular lenses (pIOLs); Artisan, Artiflex and the Implantable Collamer Lens (ICL) for correction of moderate to high myopia.

In this historical cohort study, 112 myopic eyes that were operated between 2005 and 2010 and implanted with one of these three pIOLs were evaluated (Artisan 40 eyes, Artiflex 36 eyes and ICL 36 eyes). Mean follow up period was 30±11 months. Intraoperative complications were evaluated. All patients were recalled and a complete ophthalmologic examination including refraction, best corrected visual acuity(BCVA) and intraocular pressure was performed. Pachymetry, endothelial cell count as well as postoprerative higher order aberrations were evaluated and compared with corresponding preoperative values.

No significant intraoperative complications were reported. BCVA improvement, more than one line on the Snellen chart occurred in 25%, 19.4% and 38.9% of eyes in Artisan, Artiflex and ICL groups, respectively (P=0.158). Preoperative spherical equivalent (SE) in Artisan, Artiflex and ICL groups was -11.6±3.7,-9.59±1.97 and -12.3±4.8 diopters, respectively. Reduction changes in SE was not statistically significant among the 3 groups (P=0.237). Mean reduction of astigmatism was 0.31±0.72, 0.45±0.62 and 0.0±0.57 in Artisan, Artiflex and ICL groups, respectively (P=0.07). Postoperatively, 60% of Artisan, 91.7% of Artiflex and 77.8% of ICL eyes were within one diopter of emmetropia, but the change was statistically significant between Artisan and Artiflex groups (P=0.017). Percentage of endothelial cell loss was 10±9%, 9±6% and 9±10% in Artisan, Artiflex and ICL groups, respectively (P=0.694). Pachymetry changes was minimal and the difference among groups was not statistically significant (P=0.754). Higher order aberrations (P=0.039), vertical trefoil (P=0.032) and spherical aberration (P=0.001) were higher in Artisan than ICL. Total aberrations (P=0.028) and sphericalaberration (P=0.001) was higher in Artisan than Artiflex.

Visual outcomes such as BCVA improvement, reduction in SE and astigmatism were comparable among Artisan, Artiflex and ICL groups. There was no significant intra and postoperative complications in the 3 groups. Due to the increased higher order aberrations and problems in quality of vision in myopic eyes after implantation of Artisan lens, ICL and Artiflex may be better choices.

Chemical injuries of the cornea are ophthalmic emergencies. These injuries often result in significant ocular morbidity and generally strike young adults in the prime years of life. Classification schemes enable the ophthalmologist to determine the severity of injury and the prognosis for the injured eye. Immediate management consists of copious irrigation following exposure. Effective management in the intermediate and late phases requires an understanding of the cellular events that occur during each phase. Appropriatemedical and surgical care helps ensure the best outcomes for these potentially blinding injuries. With appropriate management, it is possible to restore vision to all but the most severely burned eyes. While our current understanding of these injuries allows us to save many of these eyes, more work is needed to improve the prognosis of grade IV injuries. Ongoing animal and human research is investigating the use of novel topical agents to reduce angiogenesis, inhibit inflammation, promote repair, and reduce the risk ofcorneal melting. Efforts at preventing ocular chemical burns are equally important and deserve emphasis.

To evaluate the effectiveness of corneal collagen cross-linking with UV-A and riboflavin (CXL) for treatment of refractory herpes simplex virus necrotizing keratitis.Case Reports: Two patients with a diagnosis of HSV necrotizing stromal keratitis referred to Khalili hospital eye emergency room and who were resistant to conventional treatment underwent CXL. Response to treatment was evaluated clinically by speed of reepithelialization and decrease in stromal infiltration. One patient had history of previous corneal graft because of HSV kerstitis and had a good response to CXL.Another patient had a relatively good response, but recurrence was occurred.

Although CXL seems promising in the treatment of patients with refractory necrotizing keratitis, in some cases it may less effective and recurrence is possible.

To report a patient with exotropia due to medial rectus muscle entrapment as a complication of endoscopic dacryocystorhinostomy (EDCR).Case Report: A 34-year-old female was referred with left exotropia 18 days after EDCR for treatment of rimary nasolacrimal duct obstruction. She had a large angle left exotropia in primary position as well as omplete limitation of adduction and partial limitation of abduction in the left eye. Forced duction test was ositive in adduction and abduction, and force generation test revealed total paralysis of the left medial ectus. CT scan showed a large fracture of the medial orbital wall in which the medial rectus muscle was ntrapped. She underwent the first operation through a medial canthal incision for releasing the entrapped uscle as well as repair of the medial orbital wall defect. After two additional surgeries including medial ransposition of vertical rectus muscles and left lateral rectus muscle disinsertion she had 10 PD exotropia nd her diplopia disappeared in primary position. In addition the patient had developed optic atrophy and uperior arcuate visual field defect in her left eye probably because of intraoperative trauma to the opticnerve after EDCR.

To the best of our knowledge, this is the first report of medial rectus entrapment following DCR. This complication should be kept in mind in the approach to a patient with strabismus following ndoscopic sinus and nasal surgeries in order to select appropriate diagnostic and therapeutic measures.

To describe the clinical signs, diagnosis and treatment of toxic keratopathy in a patient who abused tetracaine drops.Case Report: A 32-year-old man was referred to the emergency ward of our center with persistent corneal epithelial defect associated with a ring infiltrate in the corneal stroma, without any history of ocular trauma or contact lens use. The patient was hospitalized and a thorough ocular examination was accomplished. A detailed history in our patient revealed topical anesthetic abuse keratitis. The topical anesthetic wasdeliberately taken from the pharmacy without a prescription. The hallmark of topical anesthetic abuse keratitis was a persistent corneal epithelial defect and a complete ring infiltration in the corneal stroma in our case. Functional and anatomic results after appropriate treatment were not favorable in this case.

Although topical anesthetic abuse keratitis is rare, it should be carefully explained to patients that although topical anesthetics numb the eye, more than a few drops can actually prevent healing and may lead to permanent damage. The unrestricted availability of topically applied ophthalmic anesthetics asover-the-counter medications in Iran must be reevaluated.