Discriminating Ability of Scanning Laser Polarimetry with Variable Corneal Compensation in Normal and Glaucomatous Eyes

PURPOSE: We investigated the diagnostic ability of scanning laser polarimetry with variable corneal compensation (GDx VCC) parameters to distinguish glaucomatous eyes with different degrees of visual field abnormality from normal eyes. METHODS: Subjects were divided into a control group (n=47) and an early to moderate glaucoma group (n=100). The latter included 53 early glaucoma patients (mean deviation > -6dB with a Humphrey Field Analyzer). Using a receiver operating characteristic (ROC) curve, the diagnostic power of GDx VCC parameters was analyzed and the correlations between those parameters and Humphrey Field Analyzer (HFA) indices were statistically analyzed. RESULTS: Nerve fiber indicator (NFI) provided the best discriminating ability with the highest area under the ROC curve (AUROC) value for detecting eyes with early to moderate perimetric glaucoma. TSNIT average showed the highest AUROC value for detecting eyes with early perimetric glaucoma. The optimal NFI cut-off value to discriminate between the control group and early to moderate group was 22, offering the best combination of sensitivity (88.0%) and specificity (83.0%). The optimal TSNIT average cut-off value to discriminate between the control group and early glaucoma group was 53.49 micrometer, providing the best combination of sensitivity (84.9%) and specificity (85.1%). Most of the thickness parameters showed higher AUROC values than those of the ratio or modulation parameters. A statistically significant correlation was found between the GDx VCC parameters and HFA indices. CONCLUSIONS: Measurement of the retinal nerve fiber layer (RNFL) by scanning laser polarimetry with variable corneal compensation is useful in discriminating between normal and glaucomatous eyes.

Study of Contralateral Eye of Normal Tension Glaucoma and a Unilateral Visual Field Defect

PURPOSE: To study the unaffected fellow eye in patients with normal tension glaucoma and unilateral visual field defect in conventional white-on-white automated perimetry, using scanning laser polarimetry and frequency-doubling perimetry. METHODS: Thirty patients with a unilateral glaucomatous visual field defect detected on conventional perimetry (Humphrey field analyzer) were selected. The contralateral eyes with normal conventional perimetry results were studied using scanning laser polarimetry and frequency-doubling perimetry. Twenty eyes of 20 age- (+/-5 years), sex-, refractive error- (+/-2 D) matched persons without glaucoma were selected as a control group. RESULTS: Of the 30 contralateral eyes, 18 eyes (60%) showed a defect of the nerve fiber layer when evaluated with SLP. In the control group, 2 eyes (8.3%) showed a defect of the nerve fiber layer. Of the 20 contralateral eyes, 14 eyes showed abnormal FDP results. In the 17 control group, 2 eyes (2%) showed abnormal FDP results. CONCLUSIONS: These findings suggest that what appeared to be unilateral visual field defects by conventional white-on-white automated perimetry may in fact underestimate structural as well as functional glaucomatous damage in the contralateral eyes. These results may be important for early detection of glaucoma and future treatment.

Ahmed valve implant and penetrating keratoplasty

PURPOSE: To present long-term results of intraocular pressure control and graft survival of eyes with penetrating keratoplasty(PKP) and Ahmed valve implant METHODS: We retrospectively reviewed medical records of 18 patients who underwent both PKP and Ahmed valve implant at Asan medical center between July of 1993 and June of 2000. Ahmed valve implant surgery was performed either before PKP (3 eyes), after PKP (12 eyes), or at the same time as PKP (3 eyes). Mean patient age was 40.7 years (range, 18 to 77 years) and mean follow up was 32 months (range, 5 to 120 months). Glaucoma outcome was assessed by postoperative intraocular pressure. Corneal outcome was assessed by graft rejection, failure and visual acuity. RESULTS: The average preoperative intraocular pressure for all of the eyes was 35 mmHg. Eighty nine percent of them (16 eyes) achieved a final intraocular pressure of less than 20 mmHg (average, 15 mmHg on a mean of 0.9 medications). Graft failure occurred in 13/16 (72%). The overall PKP success rate, including the eyes that underwent repeat PKP, was 44 %. Visual acuity improved in 8 eyes, remained stable in 5 eyes and decreased in 5 eyes. CONCLUSIONS: Ahmed valve implant can successfully control glaucoma in a majority (89%) of PKP eyes. However, the success of corneal grafts is relatively low (44%).

Three year Follow up of Laser Trabeculoplasty using Q-switched frequency doubled Nd: YAG laser

PURPOSE: To assess the efficacy and safety of selective laser trabeculoplasty treatment (SLT) using Q-switched frequency doubled Nd: YAG laser at three year follow-up. METHODS: Fifteen eyes of 12 primary open angle glaucoma patients treated between July and August 1997 with Q switched frequency doubled Nd: YAG laser were evaluated. With clinical examinations including slit-lamp examination, applanation tonometry and funduscopy, we evaluated preoperative and postoperative intraocular pressure (IOP) of treated eyes, IOP response between treated and untreated eyes, and complications at 3 year follow-up retrospectively. RESULTS: IOP before treatment was 25.2 2.3 mmHg. At one year after treatment, IOP was 20.3 4.1 mmHg (19.6% reduction). At 2 and 3 years follow-up, IOP's were 21.1 3.5 mmHg (16.4%) and 19.7 4.9 mmHg (23.2%) respectively. In the comparison between treated eyes and untreated fellow eyes, the mean IOP reduction in the untreated eyes showed 12.1%, the treated eyes showed significant reductions in IOP at all follow-ups (P=0.0003). Complication included anterior uveitis in one eye at intermediate follow-up and transient increased IOP in seven eyes. CONCLUSIONS: SLT showed stable IOP compared with preoperative intraocular pressure during 3 years follow-up period without severe complication.

The Additive of Latanoprost 0.005% in Patients with Maximum Tolerated Medical Therapy Regimen

Latanoprost 0.005% which is a currently available ocular hypotensive agent has been known to produce an additional reduction of intraocular pressure when used in combination with beta adrenergic bloker. The aim of this study was to evaluate the additive effect of this drug in patients with maximum tolerated medical therapy regimen. 48 eyes of 32 patients were categorized into 2 groups as to their type of glaucomas(primary open abgle glaucoma(POAG) vs chronic angle closure glauoma(CACG), and pilocarpine use. POAG group showed 22.3, 24.8, 22.7, 21.0, 21.4% and CACG group showed 17.6, 17.1, 15.7, 17.5, 17.8% of ocular hypotensive effect at post treatment 2 weeks, 4 weeks, 3 months, 6 months, 9 to 12 months, respectively and there was no satistically significant difference between two groups. Pilocarpine using group showed 25.5, 30.5, 26.4, 23.4, 17.8% and non-using group showed 20.6, 18.9, 19.0, 18.7, 25.1% of ocular hypotensive effect at each follow up period. Conclusively, latanoprost 0.005% appeared to be a very effective drug in reducing intraocular pressure in patients with maximum tolerated medical therapy regimen without regard to their type of glaucomas, and use of parasympathomimetics.

The Short Term Effect of Ocular Digital Massage and its Echographic Evaluation Following Ahmed Glaucoma Valve Implantation

We performed a prospective study to evaluate the effect of ocular digital massage (ODM) on intraocular pressure (IOP) in eyes that underwent implantation of Ahmed Glaucoma Valve (AGV) for refractory glaucoma. Echographic study(B scan) was also used to visualize the formation of bleb around the implant and change of its size following ODM. There were 14 eyes(13 patients) in which pre-massage IOP was 17.79 +/- 6.19 mmHg and the immediate post-massage lOP showed 11.00 +/- 6.11 mmHg . IOP in 6 hours after ODM was 15.43 +/- 7.32 mmHg . These reductions in lOP were statistically significant (paired t-test, p=0.005). When classified into two groups based on the type of glaucoma and IOP reduction after ODM was compared, there was no statistically significant difference between the group with neovascular glaucoma (NVG) and that with chronic angle closure glaucoma (t-test, p=0.328). The ultrasound study showed well formed bleb around the implant in those eyes with good IOP control. Increase in the size of bleb was shown even in those with marginal/poor IOP control following ODM. There was no significant complication associated with ODM except in one eye with persistent hypotony. In conclusion, ODM showed a significant IOP reduction in short term in eyes with AGV and its relationship with bleb size was well documented with the use of echograph.