[Superior versus inferior Ahmed glaucoma valve implantation]

To compare the efficacy and safety of Ahmed Glaucoma Valve [AGV] implantation in the superior versus inferior quadrants. This prospective parallel cohort study was performed on 106 eyes of 106 patients with refractory glaucoma. Main outcome measures included intraocular pressure [IOP] and rate of complications. Other outcome measures included best-corrected visual acuity [BCVA], number of glaucoma medications and success rate [defined as at least 30% IOP reduction and 5

[ outbreak of nocardia keratitis following photorefractive keratectomy]

To report 3 cases of nocardia keratitis following photorefractive keratectomy [PRK]. Report of Outbreak: Four eyes of 3 patients [2 female and one male] who had undergone PRK by a single surgeon at a single center developed nocardia keartitis 3 to 6 weeks postoperatively. Mean age was 25 [range 23-28] years and mean onset of corneal manifestations was 29 [range 21-40] days after PRK. Corneal smear and culture and confocal scan were performed in all eyes. Two eyes from the first two patients required lamellar keratectomy to debulk the involved stroma and to obtain specimens for microbiologic and histopathologic evaluation. Light microscopic examination disclosed gram-positive and acid-fast filaments of nocardia which were confirmed by the microbiologic results. Diagnosis of nocardia keratitis in the third case was not as challenging as the first two cases because of a high index of suspicion. Confocal scan in all cases disclosed hyperreflective and slender fibril-like structures in the corneal stroma. All eyes responded favourably to topical amikacin and the infection resolved without recurrence. Nocardia is a rare cause of keratitis following PRK. Clinical suspicion along with microbiologic, histopathologic and confocal scanning help to establish the correct diagnosis. The most probable cause of the outbreak was inadequate attention to sterility during surgery

[Intraocular lens power calculation after keratorefractive surgery]

To determine corneal power for intraocular lens [IOL] power calculation in eyes with previous keratorefractive surgery. In 13 eyes of 9 patients with previous keratorefractive surgery undergoing phacoemulcification, IOL power was calculated using the clinical history method [CHM] in one case, manual keratometry [MKR] in 2, SimK in 3, and flattest K [topographically derived] in 7 cases. SRK-T formula with applanation method was used. Final refractions [SE] are presented. Patients included 7 male and 2 female subjects aged 51.2 +/- 9.3 [range 41-70 years]. Postoperative refraction was hyperopic [+1.5 D] in eyes with the CHM, variable and unpredictable in cases with the MKR and SimK and more desirable [-0.35 +/- 0.39 D] in cases of flattest K. In this latter group the best postoperative refraction was achieved in cases which 0.5 to 1.00 D was added to the calculated IOL power. It seems using topographically derived flattest K for IOL power calculation and adding 1.00 D to the calculated IOL power in eyes with previous myopic-refractive surgery, and using the steepest K together with subtracting 1.00 D from the calculated IOL power in eyes with previous hyperopic-refractive surgery is useful when pre-refractive surgery data are not available

[Comparison of different methods for intraocular lens power calculation after corneal refractive surgery]

With the increasing number of keratorefractive surgical procedures in the past years, an increasing number of cataract operations in eyes with previous keratorefractive surgery is anticipated. Although cataract extraction seems to be feasible without major technical obstacles, intraocular lens [IOL] power calculation remains problematic. Insertion of measured k-readings after myopic photorefractive keratectomy [PRK], or laser in situ keratomileusis [LASIK] into standard IOL power-predictive formulas commonly results in substantial under correction and postoperative hyperopic refraction or anisometropia. Several methods have been developed to provide accurate measurements of corneal power which include: clinical history method, contact lens method, Feiz-Mannis formula, aphakic refraction technique, cornea bypass method and the BESSt formula. Newer methods such as the BESSt formula represent a significant step toward greater accuracy in IOL power calculation in eyes with previous laser refractive surgery, especially when prerefractive surgery data is unavailable. The "clinical history method" should be applied whenever refraction and k-reading before the keratorefractive procedure are available, however if the pre- refractive surgery data is unknown, the use of the flattest K value in the central 3 mm region of the topography map will be useful. This article briefly reviews each of the above-mentioned methods

[Intraocular lens calcification: a clinico-pathological report and review of literature]

To report the clinico-pathologic features of an opacified single-piece hydrophilic acrylic intraocular lens [IOL]. A 48-year-old male patient was evaluated for glare and markedly decreased vision in his left eye four years after phacoemulsification and implantation of a single-piece hydrophilic acrylic IOL [Ophthalmed]. Best-corrected visual acuity was 20/60 and there was diffuse milky white opalescence of the IOL on slitlamp biomicroscopy. IOL explantation and exchange was performed and the explanted IOL was evaluated at the Eye Bank pathology laboratory by light microscopy. Full-thickness sections of the optic were stained with Hematoxylin and Eosin [H and E], Von Kossa and Gram Twort's staining methods. Gross examination of the IOL disclosed opacification of the optic and haptics. Microscopic analysis of the sections revealed diffuse fine basophilic granular deposits of variable size within the lens optic parallel to the lens curvature with a clear zone from the optic surface. The deposits were of high calcium content based on the dark brown appearance on Von Kossa staining. This is the first clinico-pathological report of IOL calcification with involvement of optic and haptics in Iran. IOL exchange is an effective treatment in cases with calcified hydrogel IOLs

Delayed corneal perforation secondary to topical diclofenac use after LASEK

To report a case of delayed corneal perforation secondary to topical diclofenac usage after myopic LASEK and review of literature. A 25-year-old female with history of myopic LASEK 2 months before referred to her surgeon with epithelial defect, stromal thinning and infiltration. She was treated with antimicrobial medications for infectious keratitis for one week. She was then referred to Labbafinejad Medical Center because of lack of response and progressive stromal thinning. Two days after admission, corneal perforation was occurred. Smear and culture of the cornea were negative. She had used topical diclofenac for 6 weeks. After discontinuing the topical medications and conservative measures [oral acetazolamide, patching, simple eye ointment] the perforation started healing. Prolonged use of topical non-steroidal anti-inflammatory drugs after surface ablation may lead to stromal melting and corneal perforation; therefore, such medications should be used cautiously in these patients especially in high risk groups such as rheumatoid arthritis, dry eye syndrome, ocular surface disorders and neurotrophic keratopathy

Primary graft failure and systemic presentations of HSV infection following transplantation of an HSV-contaminated donor cornea

To report a case of primary graft failure [PGF] and systemic manifestations of herpes simplex virus [HSV] infection following transplantation of an HSV-contaminated donor cornea. A 28-year-old male with history of penetrating keratoplasty 12 days before, developed intraocular inflammation with marked anterior chamber reaction, graft edema and elevated intraocular pressure [IOP] together with systemic manifestations such as fever and unilateral cervical adenopathy. Systemic manifestations resolved after a few days but the graft edema was persistent. Regraft was performed after 3 months and the previous donor tissue was evaluated by PCR for cytomegalovirus [CMV] and HSV and was positive for HSV. HSV may be a cause of PGF, which can be transmitted by a contaminated donor cornea to the recipient. This condition may also lead to systemic symptoms