[Comparative study of three phakic intraocular lenses in correction of myopia]

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 spherical aberration [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 eye burns]

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. Appropriate medical 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 of corneal melting. Efforts at preventing ocular chemical burns are equally important and deserve emphasis

[Corneal endothelial cell loss after phacoemulsification in relation to hydrodynamic parameters: low versus high vacuum techniques]

To evaluate the effect of vacuum and flow rate on endothelial cell loss after high versus low vacuum phacoemulsification. This randomized clinical trial was performed on 60 eyes of 60 patients with moderate lens opacity [nuclear sclerosis 3+]. All surgeries were performed by one experienced surgeon using stop and chop technique with Sovereign white star machine [AMO]. Patients were randomly assigned to high and low vacuum techniques in equal numbers. The machine was set on 400 mmHg vacuum and 40 ml/min flow rate in the high vacuum group and on 200 mmHg vacuum and 20 ml/min flow rate in the low vacuum group during the chop stage. All other parameters were similar in both groups. Phacotime multiplied by average ultrasound power was defined as total ultrasound energy. Specular microscopy was performed before and 1, 6 and 12 weeks after the operation. After 12 weeks, mean endothelial cell loss was 9.0 +/- 4.0% versus 9.6 +/- 4.6% in the low and high vacuum groups, respectively [P=0.6]. Mean ultrasound power was 9.2 +/- 4.3% and 13.1 +/- 4.6% in the low and high vacuum groups, respectively [P=0.001]. Mean phacotime was 1.28 +/- 1.0 minutes in the low vacuum group versus 0.88 +/- 0.6 minutes in the high vacuum group [P=0.04]. Total ultrasound energy and total fluid volume used [turbulence] during phacoemulsification was similar between the two study groups. Total ultrasound energy was the most powerful predictor of endothelial cell loss [R2=0936, P=0.001], but turbulence was not a significant predictor [R2=0.924, P=0.1]. No significant difference in endothelial cell loss was found between low and high vacuum techniques. This study supports advice to junior surgeons to choose lower hydrodynamic phaco machine parameters; experienced surgeons can choose higher parameters to reduce phacotime

[Risk factors for posterior capsular tear and vitreous loss during phacoemulsification in a tertiary eye center]

To report the rate of vitreous loss during phacoemulsification and its contributing risk factors in patients operated on at Labbafinejad Medical Center. This prospective comparative descriptive study included patients with cataract undergoing phacoemulsification by ophthalmology residents or cornea fellows from November 2006 to November 2007. All patients underwent a complete ocular examination including visual acuity, slitlamp examination, and dilated funduscopy, preoperatively. Phacoemulsification was performed under local or general anesthesia using Divide and Conquer technique. Main outcome measures included posterior capsular tear and vitreous loss and predisposing factors such as surgeon's experience, ocular and systemic conditions, and type and severity of the cataract. Overall 767 patients including 393 male and 374 female subjects with mean age of 62.7 +/- 12.0 [range 6-96] years were studied. The overall rate of vitreous loss was 7.3% which was 5-fold higher in the hands of residents than fellows. Patients' age and female sex, small capsulorrhexis, small pupil, pseudoexfoliation, and high myopia were other significant risk factors. The highest rate of vitreous loss occurred in patients with dense nuclear cataracts. Since ophthalmology residents had a higher rate of vitreous loss, patients with risk factors such as pseudoexfoliation, high myopia, and dense nuclear cataracts are better operated by more experienced surgeons

[Keratolimbal allograft in total limbal stem cell deficiency]

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

[Stem cell deficiency in patients with chronic and delayed-onset mustard gas keratopathy]

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

[Amniotic membrane transplantation in acute ocular chemical burns]

To evaluate the role of amniotic membrane transplantation [AMT] in acute ocular chemical burns. Patients with grade II-IV [GII-GIV] ocular chemical burns [Roper-Hall classification] of less than two weeks' duration underwent AMT in addition to medical therapy. Patients were followed for at least 6 months and evaluated for ocular pain, visual acuity, epithelial defect healing, symbelpharon formation, and corneal opacity and neovascularization. Twelve eyes of 8 patients [6 male, 2 female] with mean age of 28.75 +/- 11.8 [range 12-44] years were operated. Mean duration between chemical burn and surgery was 2.5 +/- 3.3 days [range, 2 hours to 10 days]. Mean follow up period was 11.5 +/- 1.5 [range 10-13] months. The chemical agent was acidic in six eyes and alkaline in the other six. Ocular burns were GII in one eye, GIII in four eyes and GIV in seven eyes. Pain and discomfort decreased in all patients. Visual acuity improved completely in the eye with GII burn. It also improved in three eyes and remained unchanged in one eye with GIII burn. In eyes with GIV burn, two underwent tectonic corneal grafts due to perforation and two were phthisical, however visual acuity decreased in two and increased in one of the remaining eyes. The epithelial defect healed within 6 days in the eye with GII burn. Mean time for healing was 53.75 +/- 5.2 days in eyes with GIII burn. Keratolimbal allograft surgery was performed in one eye with persistent epithelial defect and severe corneal thinning. In the other two eyes, the epithelium healed in 70 and 75 days. Corneal neovascularization was seen in two eyes with GIII and all eyes with GIV burns. Corneal opacity developed in all eyes with GIII and GIV burns. Only mild symblepharon was seen in four eyes with GIV burn. AMT seems to be effective in pain reduction and prevention of symblepharon formation. It seems ineffective in preventing corneal opacification and neovascularization. The role of AMT in accelerating epithelial healing and improving visual acuity in patients with GII and GIII ocular burns needs to be evaluated in a clinical trial. It seems that prevention of symblepharon formation is the only role of AMT in eyes with GIV chemical burns

Results of post-trabeculectomy bleb revision using conjunctiva

To evaluate and compare the results of different surgical methods for post-trabeculectomy bleb revision at Labbafinejad Medical Center, Tehran-Iran, from 1999 to 2003. This study was conducted on all patients who underwent post-trabeculectomy bleb revision due to hypotony [intraocular pressure [IOP] less than 6 mmHg] or bleb leakage. Surgical methods were: conjunctival advancement, rotational conjunctival flap and free conjunctival graft. Bleb revision was performed in the cases of bleb leakage if the bleb hole was greater than 1 mm or leakage could not be controlled within 1 to 2 weeks of conservative treatment. Bleb revision was performed in eyes with hypotony in cases with cataract development or progression or hypotony maculopathy or iridocorneal adhesion. Surgical success was defined as IOP between 6-21 mmHg with a maximum of 2 topical antiglaucoma medications and discontinuation of leakage. Twenty-seven eyes of 27 patients [17 male, 10 female] with mean age of 37.8 +/- 15.2 years [9-37 years] were studied. Indication for surgery was bleb leakage in 22 cases [81.5%] and hypotonous maculopathy in 5 cases [18.5%]. Mean IOP was 4.4 +/- 1.04 mmHg preoperatively and 13.00 +/- 1.29 mmHg postoperatively. [P< 0.001] Mean visual acuity was 0.9 LogMAR [20/160] before surgery and reached 0.6 LogMAR [20/80] after bleb revision. [P<0.002] Mean cup/disc ratio was 0.7 preoperatively which remained unchanged postoperatively. Conjunctival advancement was performed in 18 cases [success rate = 72.2%], rotational conjunctival flap in 6 cases [success rate= 66.7%] and free conjunctival graft in 3 cases [success rate= 66.7%]. [P=0.73] Bleb revision was repeated in 2 cases due to continuous leakage. Mitomycin-C [MMC] and 5-fluorouracil had been used during primary trabeculectomy in 62% and 7.6% of cases, respectively. In 19.6% of cases surgery was done without using antimetabolites and usage of antimetabolites was unknown in 11%. The average time between primary trabeculectomy and bleb leakage or hypotonia was 17 months in cases with prior use of MMC and 52 months in the cases with no antimetabolite usage. [P<0.05] Post-trabeculectomy bleb revision using conjunctiva seems to be a successful method for control of leakage and prevention of complications of hypotony