[Simultaneous phacoemulsification and graft refractive surgery in post-penetrating keratoplasty eyes]

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

[Effect of relaxing incisions for post penetrating keratoplasty astigmatism on graft curvature]

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

[Deep anterior lamellar keratoplasty: review]

Lamellar keratoplasty [LK] has been a well established technique of corneal transplantation. Recent improvements in surgical instruments have revolutionized the procedure introducing a new technique employing deeper corneal dissection. This review article describes the indications, techniques, outcomes and complications of deep anterior LK

[Bilateral nocardia keratitis following photorefractive keratectomy]

To report the clinical, confocal scan, and histopathologic features of bilateral Nocardia keratitis following photorefractive keratectomy [PRK]. A 23-year-old girl underwent simultaneous bilateral PRK for myopia. On the third postoperative day, dense central infiltrates mainly involving the anterior stroma were noticed in both eyes. Clinical and confocal scan features were consistent with a diagnosis of Nocardia keratitis and topical amikacin eye drops 2% were started. Empirical antibiotic therapy was converted into specific therapy after confirming the definite diagnosis by clinical features and confocal scan. Due to poor response to medical therapy, lamellar keratectomy was performed in both eyes which shortened the treatment course. Histopathologic examination confirmed the initial diagnosis. Familiarity with the clinical and confocal scan features of Nocardia keratitis facilitates early diagnosis, proper management and hence a rapid clinical response

[Effect of corneal opacity in childhood on axial globe length in adulthood]

To evaluate the effect of childhood corneal opacity on the anteroposterior length of the globe in adulthood. 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. 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]. Corneal opacity in childhood can result in axial myopia in adulthood due to elongation of the posterior segment

[Comparison of cornel graft biomechanical properties following penetrating keratoplasty and deep anterior lamellar keratoplasty using the ocular response analyzer]

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. 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]. 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]. PK and DALK techniques provide comparable graft biomechanics in keratoconic eyes

[Corneal endothelial cell density and morphology after photorefractive keratectomy with mitomycin C]

To assess the short-term effect of Mitomycin-C [MMC] 0.02% on endothelial cell density and morphology after photorefractive keratectomy [PRK] in patients with moderate myopia. Forty-two eyes of 21 participants with moderate myopia [range, -4.0 to -8.0 D] underwent PRK with MMC 0.02% for 40 seconds. Specular microscopy was performed preoperatively and repeated 6 months after surgery to determine any change in central endothelial cell density [ECD], mean cell area [MCA], and coefficient of variation in cell size [CV]. Mean patient age was 26.2 +/- 6.3. Mean preoperative spherical equivalent refractive error was -5.2 +/- 1.2 D which was reduced to -0.4 +/- 0.5 D postoperatively [P < 0.001]. Mean ECD was reduced insignificantly from 2920 +/- 363 cells/mm2 preoperatively to 2802 +/- 339 cells/mm2 postoperatively [P = 0.59]. Similarly, there was no significant change in MCA [P= 0.76] or CV [P= 0.52] at six months. Intraoperative MMC 0.02% applied for 40 seconds during PRK for moderate myopia did not significantly change central corneal endothelial cell density and morphology after 6 months

[Corneal endothelial cell parameters after torsional versus conventional ultrasound mode phacoemulsification]

To compare corneal endothelial cell features after cataract surgery performed using fixed torsional or conventional [Pulse] ultrasound mode. In this randomized comparative study, 60 eyes were randomly and equally divided into two groups of torsional or longitudinal mode phacoemulsification. All surgeries were performed by an experienced surgeon, and the outcomes were evaluated by a masked examiner. Preoperatively visual acuity [VA], age and mean nuclear grade [LOCS III] were recorded; besides automated confocal microscopy was used to measure ECD, polymegathism and pleomorphism at the centre of the cornea. All patients underwent clear cornea phacoemulsification in a similar manner. Intraoperative outcome measures were ultrasound time [UST], cumulative dissipated energy [CDE], and total fluid use. Best corrected VA and confocal measurements were repeated after 1 month. Mean preoperative ECD in conventional and torsional phaco mode groups were 2761.61 +/- 403.36 and 2690.36 +/- 490.92 cells/mm2. Postoperative ECD was 2494.30 +/- 358.63 and 2436.56 +/- 468.39 cells/mm2, respectively. The decrease in ECD, and increase in pleomorphism and polymegatism were statistically significant within both study groups [P<.001], but there were no statistically significant differences in preoperative and postoperative measurements between the 2 groups [P>.01]. No relevant clinical differences or operative complications were seen in either group. There were no statistically significant difference between intraoperative measures in both groups [P>.01]. Both phaco methods provide effective lens removal with no significant difference

[Dry eye syndrome]

Dry eye syndrome is a multifactorial disorder of the tear film and ocular surface that results in eye discomfort, visual disturbance, and often ocular surface damage. Studies suggest that the prevalence of clinically diagnosed dry eye syndrome [DES] is 0.4%. to 0.5%, which is highest among women and the elderly. The burden of DES can be substantial, affecting visual function, daily activities, social and physical functioning, work place productivity and quality of life. This article discusses the normal anatomy and physiology of the lacrimal functional unit and tear film; pathophysiology of DES; DES etiology; classifications and risk factors; and DES diagnosis and management

[Intraocular pressure measurements after penetrating keratoplasty using the ocular response analyzer versus goldmann applanation tonometer]

To compare intraocular pressure [IOP] readings measured by the Ocular Response Analyzer [ORA] with those measured by the Goldmann applanation tonometer [GAT] in keratoconic eyes following penetrating keratoplasty [PKP] and to evaluate the influence of anatomical and biomechanical properties of the grafts on IOP measurements. This cross-sectional study was conducted on 45 keratoconic eyes undergoing PKP. IOP was measured using the GAT [IOP GAT]; corneal hysteresis [CH], corneal resistance factor [CRF], Goldmannrelated IOP [IOPg], and cornea-compensated IOP [IOPcc] were obtained using the ORA; central graft thickness [CGT] was measured by ultrasonic pachymetry. Bland-Altman and mountain plots were used to evaluate agreement between the tonometers. The correlation of graft curvature and astigmatism; central graft thickness [CGT]; and corneal biomechanical properties with IOP readings was investigated using multivariate regression analysis. Mean patient age was 29.8 +/- 6.1 years and mean follow up was 91.2 +/- 35.4 months. Mean CH, CRF, and CGT were 10.2 +/- 2.1 mmHg, 10.1 +/- 2.2 mmHg, and 565.4 +/- 37.7 mm, respectively. Mean IOP GAT, IOPg, and IOPcc were 12.2 +/- 2.4, 15.1 +/- 3.5, and 15.8 +/- 3.3 mmHg, respectively [P<0.001]. The 95% limit of agreement between IOP GAT and IOPg ranged from -3.6 to 9.3 mmHg. CH and CRF, but not CGT or keratometric astigmatism were significantly associated with IOP GAT, IOPg, and IOPcc. Graft biomechanics had more influence on IOP values as compared to anatomical features. In comparison to GAT, the ORA seem to overestimate IOP in post-PKP eyes

[Management of complications of mustard gas keratitis with corneal and limbal stem cell transplantation]

To report the clinical findings and compare the outcomes of different surgical techniques evolved over time in a large series of patients with delayed-onset mustard gas keratitis [MGK]. This interventional retrospective case series includes patients with complications of delayed MGK. Medical and surgical interventions to address dry eye, limbal ischemia and limbal stem cell deficiency [LSCD], and corneal complications were reviewed. Outcomes of limbal stem cell transplantation techniques such as living-related conjunctival-limbal allograft [lrCLAL] and keratolimbal allograft [KLAL], as well as corneal transplantation techniques including penetrating keratoplasty [PKP] and lamellar keratoplasty [LKP] were compared. A total of 175 eyes of 90 patients [all male] aged 34 to 68 years were included. Mean follow up was 101 months. The most common ocular complication was chronic blepharitis and dry eye. Conjunctival vascular abnormalities and limbal ischemia were observed in 27.4% and 29.7% of eyes, respectively. LSCD necessitating stem cell transplantation developed in 41.1% of eyes. The most common corneal signs were central and peripheral anterior stromal opacity [58.9%] followed by corneal stromal thinning [36.0%] and neovascularization [27.4%]. lrCLAL was performed in 32 eyes [18.3%] and KLAL in 40 [22.9%]. The rejection-free graft survival rate was 39.1% in the lrCLAL group and 80.7% in the KLAL group at 40 months with mean duration of 24.9 and 68.8 months, respectively [P=0.02]. 30 eyes [17.1%] underwent PKP and 51 [29.1%] received LKP. Corneal graft failure was observed in 9 [30%] PKP and 6 [11.8%] LKP eyes. The rejection-free graft survival rate was 39.0% in the PKP and 90.3% in the LKP group at 28 months with a mean duration of 29.6 and 85.0 months, respectively [P<0.001]. Chemical warfare victims may ultimately develop significant ocular involvements requiring some sorts of surgical intervention. Limbal and corneal abnormalities can best be managed by KLAL and LKP, respectively

[Lamellar keratoplasty for management of mustard gas keratitis]

To report the outcomes of manual lamellar keratoplasty [LKP] in patients with delayed-onset mustard gas keratitis [MGK] and compare visual outcomes between subgroups with simultaneous or sequential KLAL and LKP. In this retrospective, interventional study, 52 eyes of 37 male survivors of chemical warfare with MGK who underwent LKP were included. The results were evaluated with respect to best spectaclecorrected visual acuity [BSCVA], refractive error, keratometric readings and graft clarity. Eyes with sequential versus simultaneous surgery were compared in terms of BSCVA, refraction, corneal graft surface stability, and stem cell and corneal graft survival rates. Mean patient age at the time of surgery was 43.4 +/- 8.2 [36-48] years, and mean follow-up period was 41.4 +/- 19.6 [19-107] months. Mean preoperative BSCVA was 0.51 +/- 0.48 logMAR, which increased to 0.33 +/- 0.18 logMAR [P=0.03]. Mean preoperative spherical equivalent refractive error was -2.40 +/- 1.5 diopters [D], which remained unchanged postoperatively [-1.52 +/- 3.7 D, P=0.77]. No significant difference between sequential and simultaneous surgery subgroups was observed in BSCVA, refraction, keratometry readings, or corneal graft survival [90.3% and 89.9%, respectively; P=0.68]. However, the simultaneous group had statistically better stem cell survival. LKP can effectively improve BSCVA in MGK. The simultaneous approach is superior to sequential surgery when both stem cell and corneal transplantation are indicated

[Agreement among galilei, orbscan II, and placido disk-based topography]

To evaluate agreement between Galilei, Orbscan II, and placido disk-based topography in terms of keratometry readings, and anterior and posterior elevation. In this prospective comparative study, 184 eyes of 92 keratorefractive surgery candidates were evaluated with Galilei, Orbscan II, and placido disk-based topography. Keratometry readings and anterior and posterior elevation maps were compared using ANOVA and paired t-test. Mean keratometry reading by Galilei, orbscan II and corneal topography was 44.30 +/- 1.49 D, 44.11 +/- 1.47 D, and 44.60 +/- 1.56 D, respectively. The maximum difference in SimK and astigmatism obtained three devices was less than 0.5 D with respect to the anterior and posterior best fitted sphere, the agreement between the Galilei and orbscan II was 0.96 and 0.95, respectively. Maximum elevation of the anterior central cornea was 9.17 +/- 5.1 m by orbscan II and 3.2 +/- 1.78 m by Galilei. Maximum depression of the posterior central cornea was 33.84 +/- 9.33 mm and 6.81 +/- 3.78 m, respectively. Despite a significant difference in mean keratometry readings, the three devices can be used as the difference in measurements was not clinically significant. However a large amount difference was found between Galilei and orbscan II interms of anterior and posterior maximum elevation values

[Current approaches for management of post-penetrating keratoplasty astigmatism]

In addition to graft clarity, an acceptable refractive error is essential to consider a corneal transplant successful. The most common complication of penetrating keratoplasty [PK] is postkeratoplasty astigmatism which can result in decreased visual acuity, anisometropia, and mono-ocular diplopia. These complications can cause patient dissatisfaction, in spite of a successful transplant. Intraoperative measures to reduce post-PK astigmatism include round and central trephination with an appropriate size, evenly distributed suture tension, and perfect apposition of recipient and donor corneas. Suture manipulation in the early post operative period can effectively reduce astigmatism. If graft astigmatism is significant after complete suture removal and cannot be corrected using glasses or rigid gas-permeable contact lenses, further interventions such as relaxing incisions, compression sutures, laser refractive surgery, intrastromal corneal ring implants, wedge resection, and toric intraocular lens implantation can be considered. If these approaches fail to reduce astigmatism, then repeat PK becomes inevitable. A combination of the above mentioned approaches may be necessary to achieve an acceptable outcome

[Collagen cross-linking]

Patients with keratoconus constitute a large proportion of patients suffering from anterior segment disorders. As of this time, however, its pathogenesis has not yet been elucidated. A reduction in cross-link between collagen molecules has been observed in keratoconic eyes as compared to normal ones. Present approaches only address refractive errors resulting from the abnormal abnormal corneal shape. Recently, collagen cross-linking using riboflavin and ultraviolet has been introduced to slow down the disease progression. The purpose of the present study is to review the efficacy, clinical outcomes, limitations, and complications of collagen cross-linking

[Bilateral corneal scars in a patient with leprosy]

To report a known case of leprosy with bilateral corneal scars. We present a 70 year-old man who had developed claw hand deformity and loss of sensation in the extremities secondary to Leprosy since 7 years ago. Two years ago, he presented with loss of vision due to lagopthalmos and loss of corneal sensation for which he had undergone lateral tarsorrhaphy at the time. Ocular manifestations are one of the most common complications of Leprosy. Timely diagnosis and proper management can significantly decrease the burden of the disease

[ comparative study of acid and laser etching on micro shear bond strength of enamel]

With the increase of laser application in different fields of dentistry, further research is required to evaluate its efficiency in dental therapy. This study evaluated the effect of Er, Cr:YSGG laser conditioning of enamel on micro shear bond strength of composite resin of human enamel following two different tooth preparation methods [Diamond disk versus Er, Cr:YSGG laser]. In this invitro study, 125 human third molars were randomly assigned into 5 groups. Buccal and lingual enamel slices were prepared as below: A] laser-ablated without etching, B] laser-ablated and laser-etched, C] laser-ablated and acid-etched, D] cut by diamond disk and laser-etched and E] cut by diamond disk and acid-etched. Tubs of Z100 composite resin [3M, Dental Product/ USA] were bonded to conditioned enamel surfaces after applying two layers of Single Bond [3M ESPE, Dental product/ USA] Shear bond strength was measured by Micro-Tensile tester [Bisco Inc/USA] at a cross-head speed of 0.5 mm/min. Data were analyzed by one-way ANOVA, and Tukey tests. Mean shear bond strengths in groups were: A=23.14 +/- 6.53 MPa, B=23.77 +/- 5.56MPa, C=23.51 +/- 4.89MPa, D=19.30 +/- 5.56MPa and E=28.99 +/- 6.40 MPa respectively. The differences between [E, A], [E, B], [D, B], [C, D] and [D, E] were significant [P<0.05]. Micro shear bond strength of groups prepared by diamond disk and acid-etched were higher than groups prepared and etched by Er, Cr:YSGG laser. Therefore, re-etching with acid phosphoric is necessary if laser is used for tooth preparation or etching. Etching with acid phosphoric is recommended when laser is to used for tooth preparation or etching

[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

[Graft refractive surgery for post-DALK atigmatism in keratoconus]

Evaluate the effect of relaxing incision and adjustment sutures to correct astigmatism after deep anterior lamellar keratoplasty [DALK] in patients with keratoconus. This interventional case series included keratoconic eyes undergoing graft refractive surgery [GRS] for intolerable post-DALK astigmatism. The technique of graft refractive surgery for the 5 initial cases consisted of relaxing incisions at the steep meridian in the graft-host interface down to Descemet's membrane. The main outcomes were uncorrected and best-corrected visual acuity, and change in refractive and keratometric astigmatism using subtraction and vector analysis methods. Fourteen eyes of 14 keratoconic patients [12 male subjects] with history of DALK underwent GRS. Mean age of the patients was 29.36 +/- 6.2 years and mean follow-up period was 12.0 +/- 7.4 months after initial GRS. Mean preoperative BCVA was 0.29 +/- 0.1 logMAR which improved to 0.22 +/- 0.1 logMAR after the operation [P=0.007]. Average keratometric astigmatism was reduced by 3.8 D and 5.5 D as measured by subtraction and vector analysis methods, respectively. Relaxing incisions and suturing at the steep meridian followed by selective suture removal can effectively and predictably reduce post-DALK astigmatism in patients with keratoconus

[Deep anterior lamellar keratoplasty versus penetrating keratoplasty for keratoconus]

To compare the outcomes of deep anterior lamellar keratoplasty [DALK] using the big-bubble technique with that of penetrating keratoplasty [PK] in patients with keratoconus. This double-blind clinical trial included patients with moderate to advanced keratoconus and poor spectacle-corrected visual acuity or contact lens intolerance. Refractive errors, best corrected visual acuity [BCVA], contrast sensitivity function [CSF] and higher order aberrations [HOAs] were compared between the study groups. Forty-two eyes underwent DALK while 35 eyes received PK. Mean patient age was 26.91 +/- 7.9 versus 30.89 +/- 10.3 years in the DALK and PK groups, respectively [P=0.06]. Mean follow-up period was 19.0 +/- 7.9 months in the DALK and 24.6 +/- 3.5 months in the PK group [P=0.32]. Mean postoperative spherical equivalent refractive error was -3.23 +/- 3.4 D in the DALK group versus -2.22 +/- 4.6 D in the PK group [P=0.28] and mean postoperative BCVA was 0.18 +/- 0.08 logMAR and 0.15 +/- 0.10 logMAR, respectively [P=0.12]. There was no significant difference between the study groups in terms of CSF, total aberrations and HOAs. DALK may be considered as an effective alternative to PK in patients with keratoconus