Evaluation of the effect of scleral buckling on the anterior chamber angle using ASOCT.

PURPOSE: To evaluate the change in anterior chamber angle parameters after scleral buckling surgery using anterior segment optical coherence tomography (ASOCT). METHODS: Fifty-five phakic eyes of 55 subjects undergoing scleral buckling with the placement of an encircling band for primary rhegmatogenous retinal detachment were included in this study. Anterior chamber angle assessment was performed using ASOCT. The trabecular iris angle (TIA), the angle-opening distance, and the trabecular iris space area were the parameters obtained preoperatively and 48 hours, 1 week, and 1 month after the surgery using ASOCT. The intraocular pressure (IOP) was measured using Goldmann applanation tonometry. RESULTS: The mean age of the patients was 43.2±11.3 years; there were 38 male and 17 female patients. There was a significant decrease in all the angle parameters (TIA, angle opening distance, and trabecular iris space area) at 48 hours, 1 week, and 1 month after surgery (P<0.0001). TIA 180 degree decreased from 41.93±14.27 degrees preoperatively to 31.09±10.52 degrees (P<0.0001) and TIA 0 degree from 42.7±14.04 degrees to 32.92±12.17 degrees (P<0.0001) at 48 hours postoperatively. The mean IOP at 48 hours (17.04±3.26 mm Hg) was significantly higher than the preoperative level (12.68±1.96 mm Hg; P<0.001). No significant difference was noted between the mean preoperative IOP and the IOP readings at 1 week (P=0.402) and 1 month (P=0.23) postoperatively. CONCLUSIONS: ASOCT imaging reveals that scleral buckling surgery for retinal detachment induces significant narrowing of the anterior chamber angle.

Application of anterior segment optical coherence tomography in glaucoma.

Optical coherence tomography (OCT) is a cross-sectional, three-dimensional, high-resolution imaging modality that uses low coherence interferometry to achieve axial resolution in the range of 3-20 µm. Two OCT platforms have been developed: time domain (TD-OCT) and spectral (or Fourier) domain (SD/FD-OCT). Visante anterior segment OCT (Carl Zeiss Meditec) is a TD-OCT widely used for anterior segment imaging. The SD-OCT systems with both posterior and anterior segment imaging capabilities include the RTVue, iVue (Optovue), the Cirrus (Carl Zeiss Meditec), and the Spectralis (Heidelberg Engineering, Inc.). Each of the SD-OCTs has a wavelength in the range of 820-879 nm. Anterior segment OCT is a non-contact method providing high resolution tomographic cross-sectional imaging of anterior segment structures. Anterior segment OCT provides qualitative and quantitative assessment of the anterior segment structures important to the pathogenesis and the anatomical variations of glaucoma, and the approach to and success of treatment. We summarize the clinical applications of anterior segment OCT in glaucoma.

Comparison of Tono-Pen AVIA intraocular pressure measurements performed at limbus with central corneal Tono-Pen AVIA intraocular pressure.

PURPOSE: To compare Tono-Pen AVIA (TPA) intraocular pressure (IOP) measurements performed at the limbus with central corneal Tono-Pen AVIA (TPA) intraocular pressure. METHODS: Fifty-one patients attending our outpatient department with a best corrected visual acuity of ≥ 20/40, no corneal disease, and no astigmatism greater than 1.5 diopters underwent routine ophthalmological examination. Patients with ametropia greater than or equal to ± 5 diopters, a history of recent contact lens wear, and central corneal thickness of <480 µm or >550 µm were excluded from the study. IOP was recorded first in the corneal center, followed by tonometry measurements obtained from the temporal, nasal, superior, and inferior limbus using TPA. IOP measurements were compared using the paired t test. Correlation was derived by Pearson correlation coefficient, and regression equations were derived. RESULTS: The mean age of patients in our study was 43.86 ± 15.39 years. The mean TPA IOP from the central cornea was 16.59 ± 3.75 mm Hg. There was a statistically significant difference between Tono-Pen IOP from the central cornea and that recorded from all 4 limbal positions (P < 0.001). There was a positive correlation between the central and the limbal IOP obtained with Tono-Pen. Correlation was maximum for the temporal limbus. CONCLUSIONS: Limbal TPA IOP is significantly higher than central TPA IOP. There remains a good correlation between central and limbal IOP. This was found to be greatest for the temporal limbus.

Trabeculectomy with combined use of subconjunctival collagen implant and low-dose mitomycin C.

PURPOSE: To evaluate outcomes of trabeculectomy with use of a subconjunctival biodegradable collagen implant (Ologen) combined with mitomycin C (MMC). METHODS: This retrospective study included 33 eyes of 24 patients with primary open-angle glaucoma who underwent fornix-based trabeculectomy with subconjunctival Ologen implant and MMC (0.1 mg/mL×1 min) between October 2008 and April 2010. Data pertaining to the preoperative parameters and postoperative outcomes were recorded. Each patient was followed up for at least 12 months. RESULTS: The mean age of the study participants was 53.03±7.08 years. Mean preoperative intraocular pressure (IOP) was 34.06±6.56 mm Hg, and decreased to 11.87±2.23 mm Hg, 12.27±2.05 mm Hg, and 12.54±1.67 mm Hg at 3, 6, and 12 months, respectively. Mean postoperative IOP readings at all follow-up visits were significantly lower than those at preoperative levels (P<0.001). Two eyes required ocular hypotensive medications to lower the IOP in the postoperative period. All eyes had a diffuse elevated well-formed bleb, with the implant being visible for 6 to 9 months. Two eyes had a shallow anterior chamber with hypotony during the early postoperative period due to wound leak, whereas 1 case developed implant exposure at 1-week follow-up; all these cases were managed by conjunctival resuturing. Two cases developed a Tenon cyst at 8 to 12 weeks and required needling for restoration of bleb function. CONCLUSIONS: Trabeculectomy with implantation of an Ologen implant and use of low-dose MMC appears to offer encouraging short-term results for IOP control in eyes with primary open-angle glaucoma.

Course and outcome of accidental sodium hydroxide ocular injury.

PURPOSE: To evaluate the course and outcome of patients with accidental ocular alkali burns. DESIGN: Prospective, interventional case series. METHODS: Study of a cohort of 16 patients (31 eyes) who sustained concomitant accidental sodium hydroxide ocular burns and received appropriate treatment at a tertiary care eye hospital in India. The patients were followed up for 1 year, and parameters including best-corrected visual acuity, epithelial defect area, conjunctival and limbal involvement, and injury-related complications were evaluated. RESULTS: Severe sodium hydroxide exposure of a mean duration of 12 ± 2.5 minutes and delay in specialist eye care caused moderate to severe injury (grade II, 19% [n = 6]; grade III, 19% [n = 6]; grade IV, 10% [n = 3]; and grade VI, 52% [n = 16]). Median best-corrected visual acuity at presentation was 1.0 logarithm of the minimal angle of resolution (logMAR) units (range, 0.3 to 1.9 logMAR units), and at 1 year, it was 1.0 logMAR units (range, 0 to 1.9 logMAR units; P = .121). The median initial epithelial defect was 100 mm(2) (range, 18 to 121 mm(2)), which healed in all eyes by 3.5 months. Initial median limbal involvement was 12 clock hours (range, 3 to 12 clock hours), resulting in a residual limbal stem cell deficiency of 6 clock hours (range, 0 to 12 clock hours) at 1 year. Most common complications were glaucoma and cataract. Corneal ulcers developed in 2 eyes, and keratolimbal graft was performed in 1 patient. Grade VI injuries had significantly worse outcome than the lower-grade injuries. CONCLUSIONS: The course and outcome of ocular alkali burns depends on effective first aid (including a thorough eyewash), age, initial grade of injury, response to treatment, prevention of secondary infection, and control of glaucoma. Despite appropriate treatment, these eyes responded poorly and carried a guarded visual prognosis.

Prevalence of plateau iris configuration in primary angle closure glaucoma using ultrasound biomicroscopy in the Indian population.

PURPOSE: To report the prevalence of plateau iris in patients with primary angle closure glaucoma (PACG), in North India. MATERIALS AND METHODS: The patients with PACG, attending the glaucoma services at a tertiary care center in North India were included in the study. All patients had undergone Nd-YAG laser peripheral iridotomy at least four weeks prior to inclusion in the study. Four weeks prior to inclusion in the study, none of the patients had used pilocarpine. Ultrasound Biomicroscopy (UBM) images were qualitatively evaluated and plateau iris configuration was defined in an eye if the following criteria were fulfilled in two or more quadrants: anteriorly directed ciliary process supporting the peripheral iris, steep rise of iris root from its point of insertion followed by a downward angulation from the corneoscleral wall, absent ciliary sulcus, and iridotrabecular contact in the same quadrant. RESULTS: One hundred and one eyes were included in the study. There were 63 (62.4%) females and 38 (37.6%) males. The mean age of the patients was 57.8 ± 9.5 years (range: 42 to 78 years). The mean axial length in the study population was 22.2 ± 1.1 mm. The mean spherical equivalent refraction was 0.06 ± 1.12 D. The mean intraocular pressure was 18.5 ± 4.7 mmHg (range: 12 - 24 mmHg). Twenty-nine (28.7%) subjects were diagnosed with plateau iris on the basis of above-defined criteria. Of the 29 eyes, 18 (62.1%) subjects had plateau iris in two quadrants, nine (31.03%) in three quadrants, and two (6.8%) had this configuration in all the four quadrants. CONCLUSIONS: Approximately 30% of the eyes with PACG had plateau iris on UBM. Plateau iris was very often the cause for residual angle closure following laser peripheral iridotomy in Indian eyes with PACG.

Comparative evaluation of Diaton and Goldmann applanation tonometers.

AIM: To evaluate the agreement between intra-ocular pressure (IOP) measurements with the Diaton and the Goldmann applanation tonometers (GAT). METHODS: In this cross-sectional observational study, a total of 196 eyes of 196 participants (66 patients with glaucoma, 130 healthy subjects) were included. IOP measurements were obtained from all patients using the Diaton and GAT. RESULTS: The average age of the patients enrolled in this study was 48.3 ± 14.6 years (range 18-79). The overall mean IOP measured by the Diaton was 17.2 ± 6.4 mm Hg, while that in glaucoma patients was 17.9 ± 6.2 mm Hg and in the control group 15.8 ± 4.9 mm Hg. Pearson's correlation coefficient showed a moderate correlation in IOP measurements by the two instruments in healthy controls (r = 0.460, p < 0.01); however, the same correlation for the glaucomatous subjects was noted to be poor (r = 0.261, p = 0.57). The limits of agreement (95% confidence intervals) ranged from -9.9 to +11.2 and from -15.3 to +19.7 mm Hg in healthy controls and glaucoma patients, respectively. CONCLUSION: The Diaton measurements do not correlate well with those provided by applanation tonometry. The two tonometers show very wide limits of agreement so they may not be used interchangeably in clinical practice for the measurement of IOP.

The Surgical Treatment of Neovascular Glaucoma with Ex-PRESS P-50 Miniature Glaucoma Shunt.

Surgical treatment for neovascular glaucoma has evolved from cyclodestructive procedures to full-thickness filtration surgery, to trabeculectomy with antifibrosis drugs and glaucoma drainage implant surgery. The choice of a surgical approach may be influenced by several factors, including the stage of the disease. Many surgeons favor drainage implants when the disease is more advanced or when severe inflammation is present, which would be associated with a poorer prognosis if trabeculectomy were chosen. New devices are being developed to allow surgeons increased control with more predictable postoperative results. One such device, the Ex-PRESS™ mini glaucoma shunt, has undergone changes in design and method of insertion making it more appealing for use in patients requiring IOP-lowering surgery. This report highlights the use of Ex-PRESS mini glaucoma shunt in neovascular glaucoma, surgical technique and summarize pertinent literature on the role of this device in glaucoma surgery.

Ultrasound biomicroscopic assessment of angle parameters in patients with primary angle closure glaucoma undergoing phacoemulsification.

PURPOSE: To evaluate the effect of phacoemulsification and foldable intraocular lens (IOL) implantation on biometric determinants of the anterior chamber angle in primary angle closure glaucoma (PACG) using ultrasound biomicroscopy (UBM). METHODS: Forty-six eyes of 46 patients with chronic PACG and cataract having a patent laser iridotomy were included in this prospective, interventional case series. Angle parameters were measured using UBM before surgery and 3 months after phacoemulsification with IOL implantation. Intraocular pressure (IOP) was measured by applanation tonometer and records of glaucoma medication administered were maintained. Main outcome measures were IOP, central anterior chamber depth (ACD), trabecular iris angle (TIA), and angle opening distance at 250 and 500 µm from scleral spur (AOD250 and AOD500). RESULTS: The mean age of study participants was 56.5 ± 9.9 years (range 44-75). The preoperative mean IOP was 25.0 ± 5.4 mmHg on maximum antiglaucoma medication, which was reduced to 15.8 ± 3.8 mmHg (p = 0.0001) at 3 months. Number of antiglaucoma medications also decreased from 2.4 ± 1.1 to 0.4 ± 1.1 (p = 0.0001). There was a significant widening of the anterior chamber angle with the TIA increasing significantly after phacoemulsification (p<0.001) with an associated increase in AOD250, AOD500, and ACD (p<0.001). CONCLUSIONS: Phacoemulsification in eyes with PACG results in significant widening of the anterior chamber angle. This results in better IOP control after surgery and decreases the need for glaucoma medications. These findings are of clinical significance in obviating the need for simultaneous filtering surgery in eyes with PACG undergoing phacoemulsification cataract surgery.