Analysis of Factors Affecting Corneal Deflection Amplitude in Normal Korean Eyes

Purpose@#To analyze the corneal deflection amplitude (DA), as measured by the Corvis ST tonometer (Oculus), and other ocular parameters that could affect the DA in normal Korean eyes. @*Methods@#A retrospective study was performed on 126 eyes of 126 normal Korean subjects. Intraocular pressure (IOP) was measured with Goldmann tonometry (IOP-G), and the Corvis ST was used to measure the corneal DA, central corneal thickness (CCT) and IOP; the biomechanically corrected IOP-B was measured with non-contact tonometry (IOP-N). Axial length (AxL), anterior chamber depth (ACD), and the mean keratometric value were obtained with the IOL Master instrument (Zeiss). The relationships between DA and other measurements were then evaluated. @*Results@#The DA was positively correlated with AxL (p = 0.002) and ACD (p = 0.010), and negatively correlated with IOP-G (p < 0.001), IOP-N (p < 0.001), IOP-B (p < 0.001), and CCT (p = 0.006). However, when AxL, ACD, CCT, and each type of IOP were analyzed together, AxL (p = 0.016) and IOP-G (p < 0.001) were the parameters most significantly associated with the DA. @*Conclusions@#A longer AxL and greater ACD were associated with a higher DA, while a higher IOP and thicker CCT were associated with a lower DA. DA, one of the biochemical parameters of the cornea, was affected by multiple ocular factors, i.e., AxL and IOP. These factors should therefore be considered when interpreting DA measurements obtained using the Corvis ST.

Comparison of Intraocular Pressures Measured by the Corvis ST and Other Tonometers in Normal Eyes

PURPOSE@#We compared the intraocular pressures (IOPs) measured by the Corvis ST (CST), Goldmann applanation tonometer (GAT), and Rebound tonometer (RBT) and correlated the measured IOPs with the corneal center thickness (CCT).@*METHODS@#The IOPs were measured in 34 eyes of 34 normal subjects using the CST, GAT, and RBT by independent examiners. Comparisons between the IOPs measured by the CST and other tonometers were made using paired t-tests and Bland-Altman plots and Pearson's correlation coefficient was used to correlate the measured IOPs with the CCTs.@*RESULTS@#The IOP measured by the CST (C-IOP; 14.57 ± 2.37 mmHg) was significantly higher than that measured by the GAT(13.56 ± 2.25 mmHg) and RBT (13.57 ± 3.26 mmHg) (p 0.50). In analyzing the correlation with CCT, RBT-IOP (R =0.34; p = 0.705) showed a lower correlation than the GAT-IOP (R = 0.49; p < 0.01) and C-IOP (R = 0.48; p < 0.01). The C-bIOP showed no correlation with the CCT (p = 0.74).@*CONCLUSIONS@#The IOP measurements using the C-IOP were significantly higher than the RBT-IOP and GAT-IOP but the C-bIOP showed no difference from the RBT-IOP and GAT-IOP. C-IOP, RBT-IOP, and GAT-IOP were significantly correlated with corneal thickness, but there was no correlation between CCT and C-bIOP. C-bIOP may therefore be considered clinically useful.

A Family with Axenfeld-Rieger Syndrome: Report of the Clinical and Genetic Findings

PURPOSE: To describe clinical findings in a Korean family with Axenfeld-Rieger syndrome. METHODS: A retrospective review of clinical data about patients with diagnosed Axenfeld-Rieger syndrome. Five affected members of the family underwent a complete ophthalmologic examination. We screened the forkhead box C1 gene and the pituitary homeobox 2 gene in patients. Peripheral blood leukocytes and buccal mucosal epithelial cells were obtained from seven members of a family with Axenfeld-Rieger syndrome. DNA was extracted and amplified by polymerase chain reaction, followed by direct sequencing. RESULTS: The affected members showed iris hypoplasia, iridocorneal adhesions, posterior embryotoxon, and advanced glaucoma in three generation. None had systemic anomalies. Two mutations including c.1362_1364insCGG and c.1142_1144insGGC were identified in forkhead box C1 in four affected family members. CONCLUSIONS: This study may help to understand clinical findings and prognosis for patients with Axenfeld-Rieger syndrome.

Long-Term Outcomes and Predictive Factors for Success of Selective Laser Trabeculoplasty

PURPOSE: To investigate long-term outcomes and predictive success factors for selective laser trabeculoplasty (SLT). METHODS: This retrospective chart review included 66 eyes of 66 glaucoma or ocular hypertension patients who underwent SLT between 2004 and 2011. All patients were followed-up for at least 2 years after the procedure. The intraocular pressure (IOP) was measured before the treatment, at postoperative 1 week, 1 month and every 3 months thereafter. Success was defined as an IOP decrease > or = 3 mm Hg or > or = 20% of the pretreatment IOP. The success rate was determined based on the Kaplan-Meier survival analysis. The predictive success factors were analyzed using the Cox proportional hazard model. RESULTS: The mean follow-up period was 4.78 +/- 1.98 (2-8) years. The mean pretreatment IOP was 23.79 +/- 2.83 mm Hg. The mean IOP reduction was 6.64 +/- 3.21 mm Hg. The success rates were 80%, 75%, 69%, 63%, 50%, 45%, and 42% after 1, 2, 3, 4, 5, 6, and 7 years, respectively. Only high pretreatment IOP was significantly correlated with success (p = 0.044). CONCLUSIONS: SLT was an effective tool for lowering IOP in glaucoma patients. Higher pretreatment IOP was a predictive success factor.

Analysis of Peripapillary Atrophy According to the Optic Disc Shape Using Spectral Domain OCT

PURPOSE: To analyze the structural changes in the beta-zone of peripapillary atrophy (PPA-beta) using cross-sectional image of the optic disc head from spectral-domain optical coherence tomography (SD-OCT) according to the optic disc shape. METHODS: One hundred thirty-seven eyes in 137 patients with glaucoma having PPA-beta and 31 normal eyes (control group) were evaluated retrospectively. Cross-sectional images of the optic disc were taken using the Cirrus HD-OCT. We classified optic disc patterns into normal, focal, myopic, generalized enlargement and senile sclerotic appearance types and analyzed the shape of Bruch's membrane (BM), composition of retinal layer and retinal slope according to the optic disc shape. RESULTS: Among the 137 eyes with glaucoma, 54 eyes were focal disc type, 34 eyes were myopic disc type, 28 eyes were generalized enlargement disc type and 21 eyes were senile sclerotic disc type. The myopic disc group showed a noticeable difference compared to the other groups in terms of a higher percentage of BM defect type, the lowest retinal slope (70.6 +/- 12.0degrees) and the earlier termination of retinal layers. The generalized enlargement disc group showed the highest percentage of curved BM type. Retinal slope angle increased with age and decreased with axial length. CONCLUSIONS: In the beta-zone of peripapillary atrophy, there were several differences in the shape of Bruch's membrane, composition of retinal layers and the retinal slope according to the optic disc shape.

Comparison of Icare Rebound Tonometer with Goldmann Applanation Tonometry

PURPOSE: To compare Icare rebound tonometer (IRT) and Goldmann applanation tonometer (GAT) and investigate the clinical usefulness of IRT. METHODS: In a retrospective study of 131 eyes with glaucoma and glaucoma suspect, intraocular pressure (IOP) was measured with IRT and GAT. The correlation between IRT and GAT and the influence of refractive error (spherical equivalent; SE) and central corneal thickness (CCT) were analyzed. RESULTS: A distinct correlation between IRT and GAT was found. IOP measured with GAT was 2.23 +/- 3.16 mm Hg higher than with IRT (p or = -5 diopter) was measured relatively lower than in hyperopic eyes (SE < -5 diopter) with GAT (+1.50 +/- 0.68 mm Hg) and IRT (+1.88 +/- 0.75 mm Hg). CONCLUSIONS: IRT showed strong correlation with GAT, but IOP measured approximately 2 mm Hg lower. The IOP tends to measure lower at low CCT and in myopic eyes.

Analysis of Eye Drops Applying Behavior in Glaucoma Patients

PURPOSE: This study was conducted to understand the eye drop application method in patients with glaucoma. METHODS: A survey was performed in 5 hospitals on patients diagnosed with glaucoma using eye drops for more than 1 month. Variables associated with eye drop application such as pressing on a dacryocyst after application, time interval between multiple eye drop medications, hygienic management of an eye dropper and shaking a bottle of eye drops before use were evaluated. RESULTS: A total of 581 patients were surveyed in the present study. Regarding pressing on a dacryocyst after applying eye drops, 58 (10%) patients responded always, 103 patients (18%) sometimes, and 409 patients (70%) never. Three hundred fifteen patients (54%) did not touch the eye dropper to their eyes, 190 patients (33%) always shook the eye drop bottle before use and 106 patients (18%) shook the bottle sometimes. CONCLUSIONS: When using eye drops for glaucoma to reduce the intraocular pressure, most patients are committing errors, reducing the effect of treatment and likely causing side effects. When prescribing eye drops to glaucoma patients, the physician should educate patients on the proper method of application.

The Importance of Evaluation of Corneal Endothelial Cell Count in Glaucoma Patients

PURPOSE: To evaluate the possible causes of decreased central corneal endothelial cell count in glaucoma patients and to acknowledge the importance of central corneal endothelial cell count evaluation. METHODS: This retrospective case-control study included 60 glaucomatous eyes that were being treated with topical anti-glaucoma drugs, 30 eyes that underwent laser iridotomy or trabeculectomy, and 60 control eyes. Intraocular pressure, duration of topical anti-glaucoma medications, mean number of topical anti-glaucoma drugs, and preoperative central corneal endothelial cells were analyzed. RESULTS: The numbers of central corneal endothelial cells in the topical anti-glaucoma medication group, the surgical group and the control group were 2681.30 +/- 355.33, 2435.57 +/- 646.81 and 2822.08 +/- 330.17 cells/mm2, respectively. The numbers in the topical anti-glaucoma medication group and the surgical group were significantly lower than that of the control group. The number of central corneal endothelial cells was significantly low in patients with longer duration of disease and in those taking a greater number of topical anti-glaucoma drugs (p = 0.003, p = 0.010) CONCLUSIONS: In glaucoma patients, corneal endothelial cell count is decreased by glaucoma surgery, laser therapy, long-term or multiple topical anti-glaucoma medications. When performing cataract surgery in glaucoma patients, preoperative corneal endothelial evaluation is essential.

Comparison of Measured Intraocular Pressure Change According to the Methods of Corneal Refractive Surgery

PURPOSE: To evaluate differences in intraocular pressure change after three different methods of corneal refractive surgery. METHODS: The medical records of 296 eyes of 150 patients who underwent corneal refractive surgery were reviewed. Spherical equivalent, central corneal thickness (CCT), and intraocular pressure before surgery, and one month, three months and six months after surgery were analyzed. RESULTS: The patients included those having undergone laser-assisted in situ keratomileusis (LASIK; 96 eyes), IntraLASIK (98 eyes), laser assisted sub-epithelial keratomileusis (LASEK; 102 eyes). Post operative intraocular pressure in ablated corneal depth and in CCT showed a meaningful correlation. Intraocular pressure decreased significantly after refractive surgery; however, there were no differences among the three groups. CONCLUSIONS: Post operative intraocular pressure after corneal refractive surgery is influenced by CCT. There were no differences in intraocular pressure change among the three groups.

Ribbon Synapses Formed at the Axon of the Calbindin-Immunoreactive ON Cone Bipolar Cell in OFF Sublamina of the Inner Plexiform Layer in the Rabbit Retina / 체질인류학회지

Some retinal neurons, including intrinsically photosensitive retinal ganglion cells have their dendrites stratified in sublamina a of the inner plexiform (IPL), the OFF sublayer, but paradoxically show light-driven ON electrophysiological responses. In order to understand the mechanism on this paradoxical response, by using immunoelectron microscopy with a specific antibody against calbindin, we examined the synaptic connections of the calbindin-immunoreactive ON cone bipolar cell of the rabbit retina, which is thought to make the ribbon synapse in sublamina a of the IPL. The ribbon synapses in sublamina a by calbindin-immunoreactive ON cone bipolar cells were mainly found at the border between the inner nuclear layer and the IPL. Interestingly, the output targets at these ribbon synapses turned out as monads, and multiple synaptic ribbons were engaged in each synapse. These findings were different from those at the conventional ribbon synapse formed by calbindin-immunoreactive ON cone bipolar axon terminals. Thus, these findings may be the characteristics of the calbindin-immunoreactive ON cone bipolar ribbon synapse in sublamina a and can be used to classify the synapse in the retinal circuit research.

Accuracy of Intraocular Lens Power Calculation Formulas in Primary Angle Closure Glaucoma

PURPOSE: To compare the accuracy of intraocular lens (IOL) power calculation formulas in eyes with primary angle closure glaucoma (ACG). METHODS: This retrospective study compared the refractive outcomes of 63 eyes with primary ACG with the results of 93 eyes with normal open angles undergoing uneventful cataract surgery. Anterior segment biometry including anterior chamber depth, axial length, and anterior chamber depth to axial length ratio were compared by the IOL Master. Third generation formulas (Hoffer Q and SRK/T) and a fourth generation formula (Haigis) were used to predict IOL powers in both groups. The predictive accuracy of the formulas was analyzed by comparison of the mean error and the mean absolute error (MAE). RESULTS: In ACG patients, anterior chamber depth and the anterior chamber depth to axial length ratio were smaller than normal controls (all p < 0.05). The MAEs from the ACG group were larger than that from the control group in the Haigis formula. The mean absolute error from the Haigis formula was the largest and the mean absolute error from the Hoffer Q formula was the smallest. CONCLUSIONS: IOL power prediction may be inaccurate in ACG patients. The Haigis formula produced more inaccurate results in ACG patients, and it is more appropriate to use the Hoffer Q formula to predict IOL powers in eyes with primary ACG.

Glaucoma Filtering Surgery With Low Concentration of Cyclosporin A in Rabbits: A Pilot Study

PURPOSE: The effect of 0.2% cyclosporin A (CsA) as an adjuvant therapy after glaucoma-filtering surgery was the focus of this study. METHODS: A posterior lip sclerotomy was performed in 16 eyes of 8 rabbits, and 0.2% CsA was administered into the right eyes. The left eyes served as controls. The intraocular pressure (IOP) was measured 1, 3, 5, 7, 14, and 28 days after surgery. Hematoxylin-eosin (HE) and anti-bromodeoxyuridine (BrdU) immunocytochemical staining were performed at 1, 2, 4, and 8 weeks. RESULTS: The IOP at 7 and 14 days after surgery was lower in the 0.2% CsA group and statistically significant (P=0.047, P=0.48; respectively). HE staining did not show any difference between experimental and control eyes, but anti-BrdU staining showed a lower number of positive cells in the experimental eyes at 1 week. The fibroblast proliferation rate was significantly lower 1 week after surgery in the 0.2% CsA group (P=0.003). CONCLUSIONS: An effect of 0.2% CsA on early wound healing was observed. The data suggest that a low concentration of CsA can be useful when employed as adjuvant therapy in glaucoma filtering surgery.

Hypertensive Retinopathy and Associated Target Organ Damage in Korean Hypertensive Patients

PURPOSE: To report the relationship between hypertensive retinopathy and associated target organ damage in Korean hypertensive patients. METHODS: A total of 519 hypertensive patients were divided into hypertension retinopathy grades I through IV based on fundus examination. According to the grade of each hypertensive retinopathy, the frequency of target organ damage (cardiovascular disease, chronic kidney disease, and retinal vessel occlusion) and the association with hypertension retinopathy were evaluated. RESULTS: There were 211 patients (40.7%) without hypertensive retinopathy, 226 patients (43.5%) with hypertensive retinopathy grade I, 71 patients (13.7%) with grade II, seven patients (1.3%) with grade III and four patients (0.8%) with grade IV. The numbers of patients with cardiovascular disease were 103 (45.6%) in grade I, 57 (80.3%) in grade II, 3 (42.9%) in grade III, two (50.0%) in grade IV, and 70 (37.4%) in the non-hypertensive retinopathy group. According to four grades, the numbers of patients with cerebrovascular disease were three (1.3%), two (2.8%), zero (0%), and one (25.0%), respectively, with two (0.9%) in the non-hypertensive retinopathy patients. The respective numbers of patients with chronic kidney according to grades I through IV were 14 (6.2%), ten (14.0%), two (28.6%), and four (100.0%), as well as ten (4.7%) in the non-hypertensive retinopathy patients. The respective numbers of patients with retinal vessel occlusion were one (0.4%), two (2.8%), one (14.3%), and one (25.0%), with zero (0%) in the non-hypertensive retinopathy patients. CONCLUSIONS: The significance of hypertensive retinopathy should not be overlooked in Korean hypertensive patients due to an association with various target organ damage.

The Effects of Prostaglandin Analogues on the Corneal Thickness

PURPOSE: To evaluate the effects of prostaglandin analogues on the corneal thickness of patients with primary open-angle glaucoma (POAG) or normal tension glaucoma (NTG). METHODS: This study included 130 eyes of 65 patients who were diagnosed with POAG or NTG. All patients were divided into two groups; one group received prostaglandin analogues, while the other group received alternative ocular hypotensive eyedrops. Corneal thickness, best corrected visual acuity, and flare in the anterior chamber were measured and compared before treatment and at least 24 months (mean: 27 months) after treatment. RESULTS: The mean decrease in corneal thickness was statistically significant in the group using prostaglandin analogues, but not in the control group. Among the various prostaglandin analogues used, travoprost and latanoprost decreased mean corneal thickness, but bimatoprost had no effect. Best corrected visual acuity, refraction power, and flare in the anterior chamber did not change significantly in either group of patients when ocular hypotensive eyedrops were used. CONCLUSIONS: Prostaglandin analogues lower intraocular pressure and decrease corneal thickness if used over a 24 months.

The Calretinin Immunoreactive Ganglion Cell Postsynaptic to the ON-Cholinergic Amacrine Cell in the Guinea Pig

PURPOSE: To demonstrate the characterization calretinin-immunoreactive displaced amacrine cells in the ganglion cell layer using immunohistochemistry and electron microscopy. METHODS: For immunohistochemistry, sections from guinea pig retina were incubated with mouse monoclonal antibody directed against calretinin. For double label studies, sections were incuated in mixture of mouse monoclonal anti-calretinin or rabbit polyclonal anti-calretinin with following antibodies: goat polyclonal anti-ChAT, rabbit polyclonal anti-GABA, mouse monoclonal anti-GABAA receptor alpha1, beta2/3. Sections were analyzed using Bio-rad Radiance Plus confocal scanning microscope. Stained sections from three guinea pig were observed with transmission electron microscope. RESULTS: Calretinin immunoreactivity was present in displaced amacrine cells and ganglion cells gaving rise to processes ramified in the inner part of the inner plexiform layer in stratum 4. The same stratum was also occupied by the dendrites of ON-cholinergic amacrine cells. Double-labeling demonstrated that dendrites and cell bodies of displaced amacrine cells colocalized with ON-cholinergic amacrine cells and dendrites of ganglion cells directly overlapped with dendrites of ON-cholinergic amacrine cells. The synaptic connectivity was identified by electron microscopy. Ganglion cell dendrites received synaptic input from ON-cholinergic amacrine cell. GABAA receptor beta2/3 subunit bands cofaciculates the dendrites of displaced amacrine cell and ganglion cell that are juxtapose to the alpha1 subunit of GABAA receptor. CONCLUSIONS: These results indicate that ON-cholinergic amacrine cells modulate calretinin-labeled ganglion cell via GABAA receptor beta2/3 in the guinea pig retina.

Selective Laser Trabeculoplasty in Fertile Women with Open Angle Glaucoma or Ocular Hypertension

PURPOSE: To investigate the efficacy and safety of selective laser trabeculoplasty (SLT) in pregnant and lactating women who have primary open-angle glaucoma and ocular hypertension. METHODS: From January 2006 to August 2006 SLT was performed in fertile female patients with primary open-angle glaucoma and ocular hypertension. Intraocular pressure (IOP) was measured at 1 hour, 1 day, 1 week, 1 month, 3 months, and 6 months after SLT. Anterior chamber reaction and ocular pain were checked on postoperative day 1. Peripheral anterior synechia was examined at postoperative 6 months. Any anti-glaucoma drug was discontinued after SLT procedure, and restarted when needed. RESULTS: 22 patients (40 eyes) of primary open-angle glaucoma (40 eyes) and ocular hypertension (10 eyes) were included. The mean baseline intraocular pressure was 31.6 mmHg. The mean IOP was 15.7 mmHg and the mean number of anti-glaucoma drug was 1.3+/-0.6 preoperatively. There was successful IOP decrease at postoperative 1 day (17.9 mmHg), 1 week (16.3 mmHg), 1 month (17.7 mmHg), 3 months (18.4 mmHg), and 6 months (19.0 mmHg). The mean number of anti-glaucoma drug was 0.43+/-0.7 (p=0.000) postoperatively. There were no significant postoperative complications in the 6-month follow-up period. CONCLUSIONS: SLT seems to be a safe and effective procedure for fertile female patients who need to discontinue or reduce the anti-glaucoma drugs.

A Comparison of Efficacy and Safety Between 90 degrees and 180 degrees Selective Laser Trabeculoplasty

PURPOSE: To compare the intraocular pressure-lowering effect and safety between 180 degrees and 90 degrees selective laser trabeculoplasty (SLT). METHODS: From January 2006 to august 2006, in patients with primary open-angle glaucoma and ocular hypertension, SLT was performed 90 degrees to the right eye and 180 degrees to the left eye within the same patient. Intraocular pressure was checked at 1 hour, 1 day, 1 week, 1 month, 3 months, and 6 months after SLT. Anterior chamber reaction and ocular pain was checked at postoperative 1 day. Peripheral anterior synechia was examined at 6 months postoperatively. RESULTS: Fourteen patients (28 eyes) of primary open-angle glaucoma and two patients (4 eyes) of ocular hypertension were included. There was no difference of intraocular pressure between 180 degrees group and 90 degrees group preoperatively. However, there were statistically significant differences from postoperative 1 hour (p=0.003), through 1 week (15.6+/-2.3 mmHg in 90 degrees group, 14.0+/-2.5 mmHg in 180 degrees group; p=0.000), to 6 months (p=0.001). Thirty-two percent of the 90 degrees group and Seventy-five percent of the 180 degrees group showed successful intraocular pressure decrease. There was a slightly higher complication rate of anterior chamber reactions and transient intraocular pressure spikes in the 180 degrees group. CONCLUSIONS: Performing 180 degrees SLT seems the safest procedure that guarantees the successful intraocular pressure decrease.

Changes in Retinal Neuronal Population in DBA/2J Mice with Topical Intraocular Pressure Lowering Drugs

PURPOSE: The DBA/2J (D2) mouse is a transgenic mouse with pigmentary glaucoma. In a previous study, we found a reduction of inner retinal thickness in D2 mice. We attempted to discover the effect of eye drops on the retina of D2 mice. METHODS: Ten-month-old D2 mouse eyes were treated with Timoptic XE(R), Cosopt(R), and Xalacom(R) eye drops for a 1-month period. Immunohistochemical staining was performed on the mouse eye sections for analysis. RESULTS: In the control group, GABA and OPN immunoreactivity were markedly decreased and NOS immunoreactivity was increased. In all experimental group, GABA and OPN immunoreactivity were increased, and OPN immunoreactivity was markedly increased especially in the Cosopt(R) group. NOS immunoreactivity was decreased in all experimental groups. There was no difference in glycine immunoreactivity between the control and experimental groups. CONCLUSIONS: Combination anti-glaucoma eye-drops to the D2 mouse changed the retinal neuronal population and these drugs might play an important role in the mechanisms of retinal neuronal death; potential strategies for neuroprotection should therefore be evaluated.

Influence of Lens Opacity on Nerve Fiber Layer Analysis in Glaucomatous and Normal Eyes

PURPOSE: To analyze the retinal nerve fiber layer in glaucoma eyes and in normal eyes, before and after cataract surgery using GDx (Laser Diagnostic Technologies, Inc., San Diego, CA, U.S.A), - a scanning laser polarimetry, and to evaluate the effect of lens opacity on retinal nerve fiber layer analysis. METHODS: Ocular examination and GDx analysis were performed one month before and after cataract surgery on 16 eyes of 10 patients affected with glaucoma and 14 normal eyes of 9 patients at St. Mary's Hospital. Regarding the eyes affected with glaucoma, only those who showed no evidence of glaucoma progression on a visual field examination before and after the cataract surgery were included, and every cataract surgery was performed perfectly. Comparisons of the GDx parameters before and after cataract surgery were performed using the Wincoxon signed rank test. RESULTS: All GDx parameters before and after cataract surgery in normal eyes showed no significant differences. In the glaucoma patients, differences in symmetry (p=0.047), superior ratio (p=0.007), ellipse modulation (p=0.001), and GDx number (p=0.008) were statistically significant. CONCLUSIONS: GDx is an examination based on the birefringent nature of retinal nerve fiber layer so the values can change according to changes in the cornea and lens, which are birefringent. This study compared the GDx parameters before and after cataract surgery of glaucoma patients and normal eyes. Our results showed that lens opacity has a minor and subtle effect on GDx parameters, and indicated the most sensitive parameters that reflect the change of retinal nerve fiber layer. Further studies should be performed using a larger sample with statistical support.

Comparison of Short-term Outcomes of Argon Laser versus Selective Laser Trabeculoplasty in Open-Angle Glaucoma

PURPOSE: To evaluate the pressure-lowering effects of selective trabeculoplasty versus these of Argon laser trabeculoplasty. METHODS: Fifteen eyes of 15 patients with primary open-angle glaucoma and ocular hypertension, all with IOPs over 30 mm Hg received SLT and 30 eyes of 30 patients with the same diagnosis were treated with ALT. Patients were evaluated after laser treatments at 1 hour, 1 day, 1 week, 1 month, and 3 months using slit lamp examinations and Goldmann applanation tonometry. RESULTS: At 3 months postoperative, the SLT group had a mean IOP of 16.9+/-4.2 mmHg with a mean reduction of 31.2+/-20.1%, while the ALT group had a mean IOP of 17.9+/-5.4 mmHg with a mean reduction of 26.3+/-23.3%. CONCLUSIONS: Selective trabeculoplasty and Argon laser trabeculoplasty are equally effective statistically in lowering IOP over a 3-month period (p=0.47). SLT has been shown to be safe and effective in lowering IOP.