BINA
Year:2012 | Volume:17 | Issue:2 (67)|Papers Count:16

Purpose: 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.Methods: 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.Results: 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 was significantly associated with IOP GAT, IOPg, and IOPcc.Conclusion: 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.

Purpose: To compare the preoperative and postoperative measurement of intraocular pressure (IOP) using goldman applanation tonometry (GAT), the air puff and pascal dynamic contour tonometers (PDCT) in eyes undergoing myopic and myopic astigmatic photorefractive keratectomy (PRK).Methods: In a descriptional -analytic and prospective study, a complete examination was performed at the slit lamp, followed by pachymetry and pentacam imaging in patients scheduled for PRK.IOP was measured in myopic and myopic astigmatic eyes before and 2 months after PRK by GAT, PDCT and the air puff tonometer in a randomized sequence at similar times. 1) Before PRK the difference among the 3 tonometers in IOP measurement was compared 2) After PRK the difference among the 3 tonometers was compared in the same manner 3) The difference between pre-operative and post-operative measurements for each instrument was measured 4) Finally dissimilarity of changes from preoperative to postoperative among the 3 instruments was compared.Results: The study included 402 eyes (201 patients, 162 females, 39 males) with mean age of 28.7±7.03 (18- 48). Mean tonometry before PRK with GAT, PDCT and air puff was: (15.44±2.79), and (16.81±3.39), (16.31±3.36) respectively. Mean IOP after PRK with GAT, PDCT and Air puff was: (12.04±2.63), (13.57±2.91) and (11.01±3.29) respectively. The difference between 3 tonometer in IOP measurement was statistically significant (P<0.001). In the same manner the difference between 3 tonometer was statistically significant post operatively (P<0.001). There was statistically significant difference between mean pre-operative and post-operative measurement taken by the three instruments (P<0.001). There was no statistically significant difference between mean changes preoperative with postoperative measurement taken by PDCT and GAT (P=0.778). Briefly PDCT and GAT underestimate IOP approximately equally. There was a significant difference between mean changes preoperative with postoperative measurement taken by Air puff compared with GAT, and air puff compared with PDCT (P<0.001).Conclusion: Measurements of IOP may be underestimated after PRK, by GAT, PDCT and Air puff. This underestimation probably relate to biomechanical changes of the cornea after surface ablation.

Purpose: 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).Methods: 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.Results: 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).Conclusion: 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.

Purpose: To report the outcomes of conjunctival-limbal auto graft (CLAU) in patients with unilateral total limbal stem cell deficiency (LSCD) emphasizing surgical problems, complications, and their management.Methods: In this prospective interventional case series, CLAU combined with amniotic membrane transplantation as a graft was performed on 26 patients with unilateral total LSCD due to chemical or thermal injuries. Penetrating keratoplasty (PKP) was performed on eyes with dense corneal opacification. Main outcome measures were visual acuity, corneal transparency and vascularization, and complications.Results: Optical PKP was performed on 18 eyes. Best spectacle-corrected visual acuity (BCVA) was 2.28±0.45 LogMAR before CLAU which improved to 0.64±0.52 LogMAR and 0.35±0.13 LogMAR at final follow-up in eyes with and without PKP, respectively. Corneal transparency and vascularization, which were graded as 4+ before surgery, improved to a mean of 1.7±0.8 and 2.1±0.7 three months after surgery. Mean epithelial healing time was 8.8±4.1 (range 5 to 20) days. Longer healing occurred in 5 eyes due to small lenticules (n=2), exposure (n=2), and conjunctival encroachment (n=1). Mean healing period for epithelial defects over PKP was 8.8±5.5 (range 4 to 14) days. Persistent epithelial defects occurred in 8 cases with cut lenticules (n=2), small-sized lenticules (n=2), and chronic exposure (n=4). Lenticule-related complications were thick lenticules (n=4), conjunctival mantle encroachment (n=2), dislodging (n=4), progressive thinning (n=2), small size (n=3), and accidental trephination (n=2).Conclusion: CLAU combined with AMT with or without PKP is effective in anatomical and visual rehabilitation of eyes with unilateral total LSCD. This procedure increases corneal transparency and decreases vascularization. The lenticules should be handled carefully in order to avoid most common lenticule-related complications.

Purpose: 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.Methods: 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.Results: 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.Conclusion: LKP can effectively improve BSCVA in MGK. The simultaneous approach is superior to sequential surgery when both stem cell and corneal transplantation are indicated.

Purpose: To evaluate agreement between Galilei, Orbscan II, and placido disk-based topography in terms of keratometry readings, and anterior and posterior elevation.Methods: 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.Results: 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±3.78m, respectively.Conclusion: 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.

Purpose: The Impact of Photo Refractive Keratectomy Compared with Using Glasses or Contact Lens on Patient’s Quality of Life (QOL) in Myopia.Method: In this retrospective cohort study, 102 myopic patient who had undergone PRK (at least 6 months ago) and 106 myopic patients using glasses or contact lens were included. Changes in vision related QOL, uncorrected and best corrected visual acuity (UCVA, BCVA) and refraction were compared between the two groups. QOL was assessed using the VFQ-25 questionnaire which contains 25 questions in 12 subscales (score: 0-100).Result: Total QOL score in patients using glasses or contact lens, and patients who had undergone PRK was 86.1±10.7 and 97±4.4 respectively (P£0.001). In most subscales including general health, general vision, near activities, distance activities, social function, mental health, role difficulties, dependency, driving and peripheral vision, patients who had undergone PRK received higher scores and was in a better condition (P£0.001).Conclusion: Visual problems and consequential stresses are significantly decreased in patients who have undergone PRK compared with patients who use glasses or contact lens. PRK is associated with a significant increase in QOL.

Purpose: To assess various aspects of integrating a virtual reality (VR) simulator in the training of ophthalmology residents.Methods: In this qualitative study, some aspects of the VR EYESI simulator as a health technology were assessed. Data was collected using a multiple-choice questionnaire and several deep interviews addressed to users and administrators of simulator training. Face and construct validity were measured as a score out of 100. Scores were given by 19 novice residents and 4 experienced fellowship candidates.Results: Residents gave a score of 85.08 for face validity and a 70.87 for the construct validity of the EYESIsimulator. Fellowship candidates scored its face and construct validity at 60 and 80.66, respectively. 63.2% of residents believed that the simulator is a very useful training tool and 75% of fellowships viewed it as useful. Eighty percent of interviewed attending physicians believed that the simulator reduced the time and improved the quality of training. They also stated that residents who were trained with the simulator were adequately prepared for entering the operating room and showed better eye-hand coordination. All the stakeholders strongly believed that simulation is a necessary method of education.Conclusion: The EYESI simulator is an up-to-date virtual reality medium that enjoys good face and content and face validity. It was also shown to be an effective method of training since it decreased the time and improved the quality of training.

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.

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.

Purpose: To report a known case of leprosy with bilateral corneal scars.Case Report: 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.Conclusion: Ocular manifestations are one of the most common complications of Leprosy. Timely diagnosis and proper management can significantly decrease the burden of the disease.

Purpose: To describe a patient with eyelid sarcoidosis.Case Report: A 54 year-old patient was referred for an eyelid mass from 6 months ago.Excisional biopsy showed inflammatory granuloma with tuton gaint cells. Chest radiograph demonstrated bilateral hilar adenopathy, increased absorption on gallium scan was noted and bronchoalveolar lavage confirmed a diagnosis of sarcoidosis. Treatment with prednisolone was started leading to clinical improvement.Conclusion: Sarcoidosis is a multisystemic disorder and may have uncommon manifestations such as skin lesions before pulmonary signs develop.

Purpose: To evaluate all cases of drug induced angle closure glaucoma cases who presented to Feiz Hospital, Isfahan during 2008-2010.Case Report: In this retrospective case series, we present 7 cases of drug induced angle closure glaucoma after administration of Topiramate. All patients were female. The average age of patients was 33.28 years old (ranging from 19 to 44). With sufficient corneal clarity, mean BCVA was 20/400 and mean refractive error was -6.50 (rang -3.00 to-12.00) diopters. Mean intraocular pressure was 44.71 (rang 34 to 60) mmHg. Mean time normalization of intraocular pressure was 12.30 (rang 8 to 23) hours.Conclusion: Acute myopia and acute angle closure glaucoma are serious adverse effects of Topiramate, both of which are reversible with immediate discontinuation of the drug. So, taking a complete drug history and thinking about culprit drugs is critical in the evaluation of such cases.