Evaluation of visual field changes with retinal nerve fiber layer thickness in primary congenital glaucoma

Purpose: To evaluate visual field changes in primary congenital glaucoma (PCG) with retinal nerve fiber layer thickness on optical coherence tomography. Methods: In this cross?sectional, observational study, consecutive PCG children who underwent combined trabeculotomy with trabeculectomy and on regular follow?up were enrolled. All patients were aged over four years and co?operative for RNFL OCT and visual field examination. Perimetry was done on Humphrey visual field (HVF) analyzer using 30?2 and 10?2 SITA standard algorithms as appropriate. If a reliable automated perimetry was not feasible, kinetic perimetry was done. The following were noted at baseline and every follow?up: age, sex, visual acuity, intraocular pressure (IOP), cup–disc ratio (CDR), corneal diameters, refraction, any topical antiglaucoma medications, surgeries underwent, age at surgery and duration between surgery and final examination. Results: Forty?eight eyes of 34 children operated for PCG and 19 eyes of 17 controls were analyzed. A statistically significant thinner average RNFL thickness of 87.2 ± 28 ?m was noted in PCG eyes as compared to controls with 100.6 ± 7.2 ?m (P = 0.04). The mean cup–disc area ratio on OCT in PCG eyes was 0.43 ± 0.2 (0.02–0.93) and in control eyes was 0.23 ± 0.07 (0.1–0.4) (P < 0.001). On RNFL OCT, there was significant focal RNFL loss in temporal superior (P = 0.003), nasal inferior (P = 0.037) and temporal inferior (P < 0.001) quadrants compared to controls. Among PCG eyes, 20/48 eyes (41.7%), had definitive, reproducible glaucomatous VF defects. Mean baseline IOP in PCG eyes with VF defect was 28.7 ± 5.7 mmHg and in eyes with normal VF was 24.6 ± 5.9 mmHg (P = 0.03). On univariate regression analysis, higher baseline IOP was significantly associated with both RNFL loss (odds ratio (OR): ?2.17) and VF defects (OR: 3.35). Fluctuation in follow?up IOP (OR: 3.33) was also significantly associated with the presence of VF defects. On multivariable regression analysis maximum, IOP was significantly associated with RNFL loss and VF defects. Conclusion: Peripapillary RNFL thickness could be used to identify PCG eyes having visual field loss and possibly poor visual function from PCG eyes without visual field defects. Baseline and follow?up IOP, significantly correlated with RNFL thickness in PCG eyes

A Pilot, Randomized Sham Control Trial of Autologous Bone Marrow Derived Mononuclear Cells in Acute Ischemic Central Retinal Vein Occlusion.

In this pilot, sham controlled randomized control trial (RCT) in patients with ischemic central retinal vein occlusion (CRVO), we studied the safety and efficacy of intravitreal injection of autologous bone marrow derived mononuclear cells and found that both patients who received stem cell injections did not develop anterior segment neovascularization at 1 year follow up. Except for some sterile inflammatory reaction in the initial follow up, no long term injection related serious adverse events (SAEs) were observed. Based on our observations we recommend a larger, multicentric study to further establish the safety and efficacy of this treatment in patients with ischemic CRVO. Purpose: To study the safety and efficacy of autologous bone marrow derived mononuclear cells injected intravitreally in patients with ischemic CRVO. Study Design: Randomized sham controlled trial. Methods: 4 cases with ischemic CRVO were recruited into the study. 2 cases were randomized into intervention group and 2 into control group. Baseline investigations included best corrected visual acuity (BCVA), intra ocular pressure (IOP), fundus fluorescein angiography (FFA), gonioscopy and optical coherence tomography (OCT). Patients in the intervention group received intravitreal injection of autologous bone marrow derived mononuclear cells (MNCs) and those in control group received sham injection. Patients were followed up over a 12-month period. Main Outcome Measures: Development of anterior segment neovascularization. Results: Both patients in the intervention group did not develop anterior segment neovascularization over a follow up period of 12 months. 1 patient in control group developed neovascularization of iris and elevated intra ocular pressure over a follow up period of 6 weeks and required trabeculectomy for control of IOP. The other patient in control group was lost follow up after 2 weeks. Conclusions: Our initial observations suggest that intravitreal injection of mononuclear cells may reduce the risk of developing anterior segment neovascularization in patients with ischemic central retinal vein occlusion. A larger, multicentric study would be valuable to gain further evidence to our preliminary observations.

Socioeconomics of long‑term glaucoma therapy in India.

Purpose: To determine the socioeconomic impact of long‑term glaucoma therapy. Materials and Methods: One hundred and fifty consecutive glaucoma patients on medical therapy, following up at our glaucoma service for at least 6 months were recruited. A questionnaire regarding monthly income, cost of glaucoma medications prescribed, availability of medications, travel time, time spent in review clinics, compliance, education status, medical insurance and systemic or local side‑effects was administered. Results: The patients seen at the tertiary government hospital had an average monthly income of Rs. 10,912/‑ (range: Rs. 500/‑ to Rs. 50,000/‑) with approximately 56% of the patients having an income of less than Rs. 5000/month. The expenditure on anti‑glaucoma medications ranged from 0.3% in high income group to 123% of their monthly gross income in low income group (P < 0.0001). The total expenditure including travel, stay, and loss of wages of patients and accompanying persons ranged from 1.6% in high income group to 137% of the monthly income in low income group (P < 0.0001). Mean time required for a glaucoma clinic visit was 15.66 h, (range: 6–96 h/month). About 2.7% experienced systemic side‑effects and 21.3% had complaints of ocular adverse effects. About 90% of the patients were compliant. 92% were not covered by any insurance plan/government reimbursement for their treatment. Conclusions: Medical therapy for glaucoma is an economic burden to many patients and should be individualized, according to the socioeconomic status, availability of drugs and the required distance to travel to reach the specialist clinics.

Scanning laser polarimetry in glaucoma.

Glaucoma is an acquired progressive optic neuropathy which is characterized by changes in the optic nerve head and retinal nerve fiber layer (RNFL). White‑on‑white perimetry is the gold standard for the diagnosis of glaucoma. However, it can detect defects in the visual field only after the loss of as many as 40% of the ganglion cells. Hence, the measurement of RNFL thickness has come up. Optical coherence tomography and scanning laser polarimetry (SLP) are the techniques that utilize the evaluation of RNFL for the evaluation of glaucoma. SLP provides RNFL thickness measurements based upon the birefringence of the retinal ganglion cell axons. We have reviewed the published literature on the use of SLP in glaucoma. This review elucidates the technological principles, recent developments and the role of SLP in the diagnosis and monitoring of glaucomatous optic neuropathy, in the light of scientific evidence so far.

Comparative evaluation of RetCam vs. gonioscopy images in congenital glaucoma.

Purpose: To compare clarity, exposure and quality of anterior chamber angle visualization in congenital glaucoma patients, using RetCam and indirect gonioscopy images. Design: Cross‑sectional study Participants. Congenital glaucoma patients over age of 5 years. Materials and Methods: A prospective consecutive pilot study was done in congenital glaucoma patients who were older than 5 years. Methods used are indirect gonioscopy and RetCam imaging. Clarity of the image, extent of angle visible and details of angle structures seen were graded for both methods, on digitally recorded images, in each eye, by two masked observers. Outcome Measures: Image clarity, interobserver agreement. Results: 40 eyes of 25 congenital glaucoma patients were studied. RetCam image had excellent clarity in 77.5% of patients versus 47.5% by gonioscopy. The extent of angle seen was similar by both methods. Agreement between RetCam and gonioscopy images regarding details of angle structures was 72.50% by observer 1 and 65.00% by observer 2. Conclusions: There was good agreement between RetCam and indirect gonioscopy images in detecting angle structures of congenital glaucoma patients. However, RetCam provided greater clarity, with better quality, and higher magnification images. RetCam can be a useful alternative to gonioscopy in infants and small children without the need for general anesthesia.

Determinants of severity at presentation among young patients with early onset glaucoma.

Aim: The aim of this study was to evaluate the clinical, socio‑economic, and demographic factors associated with the severity at presentation among juvenile primary open angle glaucoma (JOAG) patients. Materials and Methods: Age at diagnosis, family history, baseline intraocular pressure (IOP), access to health‑care, socio‑economic status, and glaucoma awareness among 80 unrelated JOAG patients presenting between 10 years and 40 years of age were analyzed for their association with the severity at presentation. Severity at presentation was graded based on worse eye visual field using the advanced glaucoma intervention study score and on binocular visual field defects at presentation. Results: Patients with a positive family history presented 4 years earlier (P = 0.045, confidence interval [CI]: 0.09‑8.8) compared to those without a family history. Lower socio‑economic status (Odds ratio [OR] 5.7, P = 0.01, CI: 1.5‑22), and higher baseline IOP (OR 7, P = 0.003, CI: 1.9‑26) were associated with severe glaucomatous visual field defect at presentation. A negative family history was associated with a 10 times likelihood of presenting with a severe glaucomatous field defect (OR 0.1, P = 0.007, CI: 0‑0.5). Conclusions: Clinical, socio‑economic, and demographic factors are contributory to the severity at presentation among young patients with early onset glaucoma. Presence of a family history is associated with an earlier presentation among these patients and a reduced risk of the severe presentation

Scanning electron microscopy of the trabecular meshwork: Understanding the pathogenesis of primary angle closure glaucoma.

Purpose: To study ultrastructural changes of the trabecular meshwork in acute and chronic primary angle closure glaucoma (PACG) and primary open angle glaucoma (POAG) eyes by scanning electron microscopy. Materials and Methods: Twenty-one trabecular meshwork surgical specimens from consecutive glaucomatous eyes after a trabeculectomy and five postmortem corneoscleral specimens were fixed immediately in Karnovsky solution. The tissues were washed in 0.1 M phosphate buffer saline, post-fixed in 1% osmium tetraoxide, dehydrated in acetone series (30-100%), dried and mounted. Results: Normal trabecular tissue showed well-defined, thin, cylindrical uveal trabecular beams with many large spaces, overlying flatter corneoscleral beams and numerous smaller spaces. In acute PACG eyes, the trabecular meshwork showed grossly swollen, irregular trabecular endothelial cells with intercellular and occasional basal separation with few spaces. Numerous activated macrophages, leucocytes and amorphous debris were present. Chronic PACG eyes had a few, thickened posterior uveal trabecular beams visible. A homogenous deposit covered the anterior uveal trabeculae and spaces. Converging, fan-shaped trabecular beam configuration corresponded to gonioscopic areas of peripheral anterior synechiae. In POAG eyes, anterior uveal trabecular beams were thin and strap-like, while those posteriorly were wide, with a homogenous deposit covering and bridging intertrabecular spaces, especially posteriorly. Underlying corneoscleral trabecular layers and spaces were visualized in some areas. Conclusions: In acute PACG a marked edema of the endothelium probably contributes for the acute and marked intraocular pressure (IOP) elevation. Chronically raised IOP in chronic PACG and POAG probably results, at least in part, from decreased aqueous outflow secondary to widening and fusion of adjacent trabecular beams, together with the homogenous deposit enmeshing trabecular beams and spaces.

Lasers in primary open angle glaucoma.

Lasers have been used in the treatment of primary open angle glaucoma (POAG) over the years, with the hope that they would eventually replace medical and surgical therapy. Laser trabeculoplasty (LT) is an application of argon, diode, or selective laser energy to the surface of the trabecular meshwork to increase the aqueous outflow. The mechanisms by which intraocular pressure (IOP) is lowered could be mechanical, biologic, or by division of adjacent cells. It is commonly used as an adjunct to medical therapy, but is contraindicated if the angle is obstructed, e.g., peripheral anterior synechia (PAS) or developmental glaucomas. About 75% of individuals will show a significant fall in IOP after argon laser trabeculoplasty (ALT), and the response is similar with selective laser trabeculoplasty (SLT). The effects of LT are not always long lasting, with about 10% of individuals showing a rise in IOP with every passing year. Laser thermal sclerostomy, ab interno or externo, is an alternative to other full-thickness filtration procedures. Longer wavelengths in the infrared range have water-absorptive characteristics that facilitate perforation of the sclera. These lasers can be used to avoid intraocular instrumentation and minimize conjunctival trauma.

An Indian perspective on primary angle closure and glaucoma.

Aim: To provide a synopsis of primary angle closure disease in India, and Indian studies on the same. Results: Primary angle closure glaucoma forms almost half of all adult primary glaucomas seen in a hospital setting in India. Anatomically, corneal diameters and anterior chamber depths were least in acute and chronic PACG eyes as compared to subacute eyes and controls. Besides relative pupillary block, a Valsalva maneuver during activities of daily living may be responsible for intermittent angle closure and raised IOP in predisposed eyes. Iridotomy alone, controlled the intraocular pressure in 66.7% of subacute eyes and 12.9% of the acute. Medical therapy was additionally required for 35.5% of the acute eyes, 12.1% of the subacute and 30.0% of the chronic cases. There was a greater mean and peak IOP reduction, achieved with 0.005% latanoprost once daily, 8.2 ± 2.0 mm Hg, compared with 0.5% timolol twice daily, 6.1 ± 1.7 mm Hg2. A progression of PACS to PAC was seen in 22%, PAC to PAC OHT in 38.7% and PAC OHT to PACG in 30.7% over 5 years. Conclusions: Primary angle closure disease is common in India, and can be managed well with iridotomy, followed by an appropriate control of IOP.

Comparison of the diagnostic ability of Moorfield’s regression analysis and glaucoma probability score using Heidelberg retinal tomograph III in eyes with primary open angle glaucoma.

Purpose: To compare the diagnostic performance of the Heidelberg retinal tomograph (HRT) glaucoma probability score (GPS) with that of Moorfield’s regression analysis (MRA). Materials and Methods: The study included 50 eyes of normal subjects and 50 eyes of subjects with early-to-moderate primary open angle glaucoma. Images were obtained by using HRT version 3.0. Results: The agreement coefficient (weighted k) for the overall MRA and GPS classification was 0.216 (95% CI: 0.119 – 0.315). The sensitivity and specificity were evaluated using the most specific (borderline results included as test negatives) and least specific criteria (borderline results included as test positives). The MRA sensitivity and specificity were 30.61 and 98% (most specific) and 57.14 and 98% (least specific). The GPS sensitivity and specificity were 81.63 and 73.47% (most specific) and 95.92 and 34.69% (least specific). The MRA gave a higher positive likelihood ratio (28.57 vs. 3.08) and the GPS gave a higher negative likelihood ratio (0.25 vs. 0.44).The sensitivity increased with increasing disc size for both MRA and GPS. Conclusions: There was a poor agreement between the overall MRA and GPS classifications. GPS tended to have higher sensitivities, lower specificities, and lower likelihood ratios than the MRA. The disc size should be taken into consideration when interpreting the results of HRT, as both the GPS and MRA showed decreased sensitivity for smaller discs and the GPS showed decreased specificity for larger discs.

Effect of cataract surgery on retinal nerve fiber layer thickness parameters using scanning laser polarimetry (GDxVCC).

Purpose: To study the effect of cataract extraction on the retinal nerve fiber layer (RNFL) thickness, and assessment by scanning laser polarimetry (SLP), with variable corneal compensation (GDx VCC), at the glaucoma service of a tertiary care center in North India. Materials and Methods: Thirty-two eyes of 32 subjects were enrolled in the study. The subjects underwent RNFL analysis by SLP (GDx VCC) before undergoing phacoemulsification cataract extraction with intraocular lens (IOL) implantation (Acrysof SA 60 AT) four weeks following cataract surgery. The RNFL thickness parameters evaluated both before and after surgery included temporal, superior, nasal, inferior, temporal (TSNIT) average, superior average, inferior average, and nerve fiber index (NFI). Results: The mean age of subjects was 57.6 ± 11.7 years (18 males, 14 females). Mean TSNIT average thickness (μm) pre- and post-cataract surgery was 49.2 ± 14.1 and 56.5 ± 7.6 (P = 0.001). There was a statistically significant increase in RNFL thickness parameters (TSNIT average, superior average, and inferior average) and decrease in NFI post-cataract surgery as compared to the baseline values. Mean NFI pre- and post-cataract surgery was 41.3 ± 15.3 and 21.6 ± 11.8 (P = 0.001). Conclusions: Measurement of RNFL thickness parameters by scanning laser polarimetry is significantly altered following cataract surgery. Post the cataract surgery, a new baseline needs to be established for assessing the longitudinal follow-up of a glaucoma patient. The presence of cataract may lead to an underestimation of the RNFL thickness, and this should be taken into account when analyzing progression in a glaucoma patient.

Bilateral iridocorneal endothelial syndrome in a young girl with Down's syndrome.

We describe the occurrence of bilateral iridocorneal endothelial (ICE) syndrome with glaucoma in a young girl with Down's syndrome. A 16-year-old girl with Down's syndrome was found to have secondary glaucoma in the right eye with features of progressive iris atrophy in both eyes. She was uncontrolled on maximum tolerable medical therapy for glaucoma. She underwent an uneventful trabeculectomy with mitomycin-C in her right eye. Scanning electron microscopy of the trabecular meshwork obtained in this case is described.

Post-penetrating keratoplasty glaucoma.

Post-penetrating keratoplasty (post-PK) glaucoma is an important cause of irreversible visual loss and graft failure. The etiology for this disorder is multifactorial, and with the use of new diagnostic equipment, it is now possible to elucidate the exact pathophysiology of this condition. A clear understanding of the various mechanisms that operate during different time frames following PK is essential to chalk out the appropriate management algorithms. The various issues with regard to its management, including the putative risk factors, intraocular pressure (IOP) assessment post-PK, difficulties in monitoring with regard to the visual fields and optic nerve evaluation, are discussed. A step-wise approach to management starting from the medical management to surgery with and without metabolites and the various cycloablative procedures in cases of failed filtering procedures and excessive perilimbal scarring is presented. Finally, the important issue of minimizing the incidence of glaucoma following PK, especially through the use of oversized grafts and iris tightening procedures in the form of concomitant iridoplasty are emphasized. It is important to weigh the risk-benefit ratio of any modality used in the treatment of this condition as procedures aimed at IOP reduction, namely trabeculectomy with antimetabolites, and glaucoma drainage devices can trigger graft rejection, whereas cyclodestructive procedures can not only cause graft failure but also precipitate phthisis bulbi. Watchful expectancy and optimal time of intervention can salvage both graft and vision in this challenging condition.

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 <or=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 <or=20/200. CONCLUSIONS: Most patients with secondary glaucoma have poor vision (<or=20/200) with high IOP and advanced fundus changes at presentation.

Transconjunctival penetration of mitomycin C.

AIMS: The study was performed to estimate transconjunctival penetration of mitomycin C (MMC) to Tenon's tissue following application over the intact conjunctiva before routine trabeculectomy. SETTINGS AND DESIGN: Institution-based case series. MATERIALS AND METHODS: In 41 eyes of 41 patients, MMC (0.4 mg/ml for 3 min) was applied over the intact conjunctiva before beginning trabeculectomy. Tenon's capsule directly beneath the site of application was excised during trabeculectomy and was homogenized, centrifuged and MMC concentrations were analyzed using high-performance liquid chromatography (HPLC). Statistical Analysis Used: Statistical analysis was performed using STATA 8.0 version software (STATA Corporation, Houston, TX, USA). In this study, P -values less than 0.05 were considered as statistically significant. RESULTS: The average weight of the sample of Tenon's tissue excised was 5.51+/-4.42 mg (range: 0.9-17.1) and the average estimated MMC concentration found to be present in Tenon's tissue using HPLC was 18.67+/-32.36 x 10(-6) moles/kg of the tissue (range: 0.38-197.05 x 10(-6)). In 36 of the 41 patients (87.80%), the MMC concentration reached above 2 x 10(-6) moles/kg of the tissue concentration required to inhibit human conjunctival fibroblasts. CONCLUSIONS: Mitomycin C does permeate into the subconjunctival tissue after supraconjunctival application for 3 min. Application of MMC over the conjunctiva may be a useful alternative to subconjunctival or subscleral application during routine trabeculectomy and as an adjunct for failing blebs.

Evaluation of retinal nerve fiber layer thickness measurement following laser in situ keratomileusis using scanning laser polarimetry.

AIM: To evaluate the effect of laser-assisted in situ keratomileusis (LASIK) on the measurement of retinal nerve fiber layer thickness by scanning laser polarimetry using customized corneal compensation in myopes. MATERIALS AND METHODS: Scanning laser polarimetry was performed on 54 eyes of 54 healthy patients with myopia using the glaucoma diagnostics variable corneal compensation (GDx VCC) instrument (Laser Diagnostic Technologies, San Diego, California) before and a week after LASIK. The various parameters were compared using the Student's t test. RESULTS: No statistically significant change was observed in any of the retinal nerve fiber layer parameters before and after LASIK. CONCLUSIONS: While the measurement of retinal nerve fiber layer thickness by scanning laser polarimetry is affected by anterior segment birefringent properties and LASIK would be expected to produce changes in the same, customized corneal compensation using the GDx VCC seems to adequately compensate for these changes.

Inter-instrument agreement and influence of central corneal thickness on measurements with Goldmann, pneumotonometer and noncontact tonometer in glaucomatous eyes.

PURPOSE: This study was conducted to compare the intraocular pressure (IOP) measurements by the Goldman applanation tonometer (GAT), non contact tonometer (NCT) and the ocular blood flow (OBF) pneumotonometer in different IOP ranges in glaucomatous eyes. The effect of central corneal thickness (CCT) on IOP measurement in chronic glaucomatous eyes using the three different tonometers was also evaluated. MATERIALS AND METHODS: IOP measurements of 130 eyes of primary glaucoma patients were performed using GAT by an ophthalmologist while NCT and OBF-pneumotonometer measurements were performed by an experienced optometrist. The IOP values were compared amongst the three instruments in the three different IOP ranges (0-18 mmHg, > 18 to 25 mmHg, > 25 mmHg). CCT was also measured in all patients. RESULTS: The mean of paired difference between GAT and NCT was 0.9 +/- 3.1 mmHg while that between GAT and OBF-pneumotonometer was 0.3 +/- 3.4 mmHg. The OBF-pneumotonometer and NCT were more affected by corneal thickness (0.41 mmHg and 0.4 mmHg / 10 micro corneal thickness respectively) while GAT was the least affected by corneal thickness (0.3 mmHg / 10 micro corneal thickness) though the difference was not statistically significant ( P =0.42). CONCLUSION: With appropriate correction for corneal thickness the NCT and OBF-pneumotonometer can be used as reliably as GAT in following up glaucomatous patients.

A comparison of the circadian rhythm of intraocular pressure in primary phronic angle closure glaucoma, primary open angle glaucoma and normal eyes.

PURPOSE: To evaluate the circadian rhythm of intraocular pressure (IOP) in primary chronic angle closure glaucoma (PCACG), primary open angle glaucoma (POAG), and normal eyes. METHODS: Cross-sectional study of newly diagnosed patients of POAG (60 eyes), PCACG following laser iridotomy (75 eyes), and age and sex matched normal controls (75 eyes). All subjects underwent applanation tonometry at 7 a.m., 10 a.m., 1 p.m., 4 p.m., 7 p.m., and 10 p.m. by a masked observer. Circadian rhythms were classified based upon the timing and presence of peak pressure. RESULTS: Age and gender in all three groups were comparable. Diurnal IOP fluctuations were significantly higher in PCACG (7.69+3.03 mmHg) and POAG (8.31+2.58 mmHg) groups compared to normal controls (4.83 + 2.46 mmHg). PCACG eyes and controls had similarly timed circadian rhythms, with PCACG eyes having a consistently higher IOP. At 7 and 10 a.m., IOP peaked more often in POAG eyes compared to PCACG eyes. A plateau type of circadian rhythm was most common in normal eyes. The timing of peak IOP could be significantly correlated with the type of primary glaucoma examined. CONCLUSION: Afternoon peaks were more common in postiridotomy PCACG eyes, similar to the rhythm in normal eyes. Morning peaks were more frequent in POAG eyes. Diurnal fluctuation > 6 mmHg, associated with an IOP of 21 mmHg or more was never seen in a normal eye.

Quantification of the retinal nerve fibre layer thickness in normal Indian eyes with optical coherence tomography.

PURPOSE: To quantitatively assess the normative values for peripapillary retinal nerve fibre layer (RNFL) thickness with Optical Coherence Tomography (OCT 3) in Indian subjects. METHODS: The peripapillary retinal nerve fibre layer of 146 normal subjects was imaged on OCT 3 in this cross-sectional study. Thickness of the RNFL around the disc was determined with three 3.4 mm diameter circle OCT scan. The RNFL thickness was measured in four quadrants; superior, nasal, inferior and temporal. The data was analysed using SAS commercial statistical software. Influence of age and gender was evaluated on various measured parameters using unpaired t test, one-way analysis variance (ANOVA) and Pearson's correlation coefficient. RESULTS: One hundred and forty six eyes of 146 patients, 84 males and 62 females were studied. The average RNFL thickness in the sample population under study was 104.27 +/- 8.51 (95% CI 87.25-121). The RNFL was thickest in the inferior quadrant, followed by the superior quadrant, and progressively less in nasal and temporal quadrant. The difference between inferior and superior quadrants was not statistically significant. Age had a significant negative correlation with average RNFL thickness (r = -0.321, P = 0.000) and with average superior (r = -0.233, P = 0.005) and average inferior RNFL thickness (r = -0.234, P = 0.004). There was no effect of gender on various RNFL thickness parameters. CONCLUSIONS: RNFL thickness is significantly correlated with age, but not with gender. This normative database of RNFL thickness with OCT in Indian eyes is similar to previously reported values in normal Asian eyes.