Ritu Gadia

Comparison of anterior segment optical coherence tomography and ultrasound biomicroscopy for assessment of the anterior segment

PURPOSE: To compare anterior segment parameters using quantitative imaging by anterior segment optical coherence tomography (AS‐OCT) and ultrasound biomicroscopy (UBM). SETTING: Tertiary‐care glaucoma research center. METHODS: Sixty‐three eyes of 63 subjects had anterior segment evaluation by AS‐OCT (Visante‐Zeiss) and UBM (Paradigm). Central corneal thickness (CCT), anterior chamber depth (ACD) (measured from the central corneal endothelium to the anterior lens capsule), and the peripheral iridocorneal angles (temporal and nasal) were assessed and compared. RESULTS: There was an excellent correlation between AS‐OCT and UBM measurements for the nasal angle (r = 0.84; P<.0001), temporal angle (r = 0.86; P<.0001), ACD (r = 0.97; P<.0001), and CCT (r = 0.91; P<.0001). There was no significant difference (paired t test) between the mean ACD, CCT, and angle parameters measured by AS‐OCT or UBM. The mean values of the parameters measured by AS‐OCT and UBM were, respectively, as follows: nasal angle, 26.25 degrees ± 11.0 (SD) and 28.27 ± 11.3 degrees (P = .3); temporal angle, 25.1 ± 11.4 degrees and 28.3 ± 13.5 degrees (P = .15); ACD, 2.85 ± 0.5 mm and 2.78 ± 0.5 mm (P = .2); and CCT, 512 ± 46 μm and 502 ± 46 μm (P = .25). The AS‐OCT images showed sharper definition of the scleral spur than the UBM images. CONCLUSION: Anterior segment optical coherence tomography and UBM can both be used for anterior segment measurements and yielded comparable results.

Evaluation of distance and near stereoacuity and fusional vergence in intermittent exotropia

Aim: To evaluate the role of distance and near stereoacuity and fusional vergence in patients with intermittent exotropia [X(T)] and their change after surgery. Materials and Methods: This prospective interventional institution-based clinical study included 31 cases of X(T) requiring surgery and 33 age, sex-matched controls. All subjects underwent complete orthoptic assessment including near stereopsis (Randot stereogram) and distance stereopsis by polaroid stereo- projector apparatus using special paired slides and fusional vergence assessment at distance and near prism bar at baseline and one week, one month, three months and six months after surgery in X(T). Results: The successful surgical alignment rate was 74.2%. Preoperatively, cases demonstrated significantly poor distance and near stereoacuity, compared to controls (P < 0.001). Mean distance stereoacuity (sec of arc) in normals, (X)T preoperatively and postoperatively was 344.8 ± 139.5, 1149.2 ± 789.4 and 450.1 ± 259 while mean near stereoacuity was 34.7 ± 9.5, 68.7 ± 31.1 and 47.4 ± 22.6 respectively. Postoperatively at six months, significant improvement in stereoacuity was observed both at near and distance (P < 0.05). Mean distance fusional convergence (in prism diopter) in normals, X(T) preoperatively and postoperatively was 20.7 ± 4.7, 18.0 ± 3.3 and 21.4 ± 3.6 respectively, mean near fusional convergence was 27.8 ± 6.3, 24.1 ± 5.5 and 29.1 ± 5.5 respectively. There was good correlation between fusional vergence amplitudes for distance and near indicating any one would suffice. Conclusion: Early detection of abnormal stereoacuity (near and if possible distance) and near fusional vergence amplitudes may help to decide proper timing of surgery in X(T).

Current profile of secondary glaucomas.

Purpose: To study the current profile of secondary glaucomas for their incidence and to identify risk factors. Materials and Methods: In this retrospective chart review, 2997 patients newly diagnosed and referred with glaucoma to our tertiary glaucoma center in the year 2005 were included. Evaluation of all cases was done on the basis of a detailed history and recorded examination including vision, intraocular pressure (IOP), anterior segment examination, gonioscopy and fundus evaluation by glaucoma specialists. Demographic data, etiology of secondary glaucoma, and any other significant findings were noted. Results: Of 2997 referred patients, 2650 had glaucoma or were glaucoma suspects. Of all glaucoma patients or glaucoma suspects, 579 patients (21.84%) had secondary glaucoma. Age distribution was as follows: 25% were between 0-20 years; 27% were between 21-40 years; 30% were between 41-60 years and 18% were >60 years. The male female ratio was 2.2. Frequent causes of secondary glaucoma were post - vitrectomy 14%, trauma 13%, corneo-iridic scar 12%, aphakia 11%, neovascular glaucoma 9%. Post-vitrectomy glaucoma eyes had vitreous substitutes in 83% cases of which 66% eyes had retained silicone oil for more than three months. Vision ≤20/200 was present in 63% eyes, 57% eyes had baseline IOP > 30 mm Hg. Of all traumatic glaucoma patients, 71% cases were <30 years of age. Fifty per cent had baseline IOP of >30 mm Hg and vision ≤20/200. Conclusions: Most patients with secondary glaucoma have poor vision (≤20/200) with high IOP and advanced fundus changes at presentation.

Sutureless single-port transconjunctival pars plana limited vitrectomy combined with phacoemulsification for management of phacomorphic glaucoma

&NA; We describe a technique that uses a small‐gauge, single‐port, sutureless transconjunctival limited pars plana vitrectomy to facilitate phacoemulsification in eyes with a shallow anterior chamber and high intraocular pressure (phacomorphic glaucoma). These eyes have positive vitreous pressure, and anterior chamber formation with an ophthalmic viscosurgical device may not be possible. Surgery is difficult and prone to various intraoperative complications.

Retinal nerve fiber layer thickness measurement by scanning laser polarimetry (GDxVCC) at conventional and modified diameter scans in normals, glaucoma suspects, and early glaucoma patients.

PurposeTo study the retinal nerve fiber layer (RNFL) at 3 different scan diameters using GDxVCC in healthy, primary open-angle glaucoma (POAG) suspects, and early POAG. MethodRNFL parameters were evaluated in 100 normal subjects, 50 POAG suspects, and 50 early POAG patients using GDxVCC at conventional small, medium, and large circle. TSNIT (temporal, superior, nasal, inferior, temporal) average, superior average, inferior average RNFL thickness, and nerve fiber indicator (NFI) were evaluated. ResultsThe TSNIT average (μm) in normal subjects, POAG suspects, and POAG at 3 different circles was 54.17±4.6, 49.96±6.5, 46.92±6.2 (small); 47.17±4.8, 43.79±5.7, 41.48±6.5 (medium); and 41.57±4.6, 39.77±5.9, 38.33±7.1 (large). All RNFL parameters at all circles showed significant difference between normal and early POAG eyes (P<0.001). Area under the curve was 0.911 for NFI at all circles. All parameters at small and medium circle, all except TSNIT average at large circle showed significant difference between normal and POAG suspects (P<0.001), area under curve being the highest (0.780 to 0.801 at 3 circles) for NFI. All parameters progressively decreased with increasing diameter with significant difference between small-medium (P<0.001), medium-large (P<0.001), and small-large circle results (P<0.001) in all the groups for all parameters except NFI. ConclusionsMedium and large circles can also be used for RNFL evaluation in glaucoma. NFI is the best discriminating measure across all scan diameters.

Prehypertension may be common in patients with central serous chorioretinopathy

PurposeTo test an observational hypothesis that patients with central serous chorioretinopathy (CSCR) may have a tendency towards hypertension compared with normal individuals.MethodsIn this case–control study we evaluated resting blood pressure in 32 patients with CSCR and compared it with that in 32 healthy controls in a standard laboratory environment. Differences in resting systolic and diastolic blood pressure were measured.ResultsMean systolic blood pressure was 123.56+/−4.8 in the CSCR group and 113.63+/−12.62 in the control group. Mean diastolic blood pressure was 84.75+/−10.2 in the CSCR group and 76.75+/−0.4 in the control group. The difference in mean blood pressure values between the two groups was statistically significant.ConclusionPatients with CSCR may be predisposed to prehypertension. Hence they should be advised on lifestyle modification and followed up periodically for early detection of progression to stage 1 or 2 hypertension.