Study of retinal nerve fibre layer thickness in eyes with high tension glaucoma and hemifield defect

AIM

To quantitatively evaluate retinal nerve fibre layer (RNFL) difference in areas of apparently normal appearing visual field in eyes with high tension glaucoma (HTG) and hemifield defects using scanning laser polarimetry.

METHODS

40 eyes from 40 patients with HTG with superior or inferior hemifield defects based on the Humphrey field analyser (HFA) underwent RNFL thickness measurements. 20 normal eyes from 20 subjects matched in age and refractive error were selected as a control group. The RNFL thickness was measured with a scanning laser polarimeter. Mean RNFL thickness was evaluated in four quadrants (superior, inferior, nasal, and temporal). A superior or inferior quadrant in the defined ring of scanning laser polarimetry corresponds to inferior or superior hemifield in HFA.

RESULTS

The mean RNFL thickness in the unaffected quadrant (the quadrant corresponding to the hemifield with apparently normal visual field based on HFA) of the HTG group was significantly thinner than the average RNFL thickness of the corresponding quadrant of the control eyes. The RNFL thickness of the unaffected quadrant in the eyes with HTG was reduced and statistically similar to that of the affected quadrant. Symmetry, calculated as the ratio of superior to inferior RNFL thickness, showed no statistical difference between the study and control group.

CONCLUSION

Changes in RNFL are present in the apparently normal hemifield in the eyes with HTG. The thickness of the RNFL is reduced symmetrically in both superior and inferior quadrants based on the GDx parameters.

Short-term effect of mitomycin-C augmented trabeculectomy on axial length and corneal astigmatism

PURPOSE

To evaluate the short-term effect of trabeculectomy with adjunctive mitomycin-C (MMC) on corneal astigmatism and axial length.

SETTING

Asan Medical Center, University of Ulsan, Department of Ophthalmology, Seoul, Korea.

METHODS

Eighteen consecutive eyes of 16 patients having trabeculectomy with adjunctive MMC were prospectively analyzed. Intraocular pressure (IOP) and axial length were evaluated preoperatively and 1, 3, 6, and 12 months postoperatively. Postoperative changes in corneal astigmatism were evaluated using vector analysis.

RESULTS

The overall mean induced astigmatism showed with-the-rule change up to 3 months postoperatively followed by an against-the-rule shift. The mean axial length was significantly less postoperatively and changed throughout the 12 month follow-up. There was a positive correlation between postoperative axial length and IOP. Eyes with higher preoperative IOP had a greater decrease in axial length after trabeculectomy with MMC.

CONCLUSION

The induced corneal astigmatism after trabeculectomy with MMC was long lasting, although less than that in previous studies. The change in axial length after surgery was significant, especially in eyes with a high preoperative IOP. The decrease in axial length persisted throughout the follow-up.

Reproducibility of scanning laser polarimetry (GDx) of peripapillary retinal nerve fiber layer thickness in normal subjects

PURPOSE

To assess the reproducibility of measurement of retinal nerve fiber layer (RNFL) thickness among subjects using the GDx Nerve Fiber Analyzer (NFA).

METHODS

One eye of each of five young and healthy volunteers was imaged by three newly trained technicians (R.-H.P, K.-R.K., and S.-T.K.). Each volunteer was scanned six consecutive times for five independent times within a 1-month period. One composite image was selected out of three best images per session. Intra- and interoperator reproducibilities were calculated and the influence of placement of measurement ellipse by a single operator on interobserver reproducibility was also investigated.

RESULTS

Mean coefficients of variation for total integral value of RNFL were 3.67 +/- 1.47%, 3.86 +/- 2.13%, and 4.16 +/- 1.97%, respectively for the three technicians. Interoperator variability was not statistically significant (P = 0.075), and the difference was even less if a single ellipse drawn by one operator was used in all measurements (P = 0.1528) by repeated-measures analysis of variance (ANOVA).

CONCLUSIONS

The results suggest that GDx NFA may provide acceptable intraoperator as well as interoperator reproducibility among Asian eyes.

Increases in intraocular pressure during hemodialysis in eyes during early postvitrectomy period

BACKGROUND AND OBJECTIVES

To identify risk factors for intraocular pressure (IOP) increases during hemodialysis (HD) in the early postoperative period following pars plana vitrectomy (PPV).

PATIENTS AND METHODS

Comparisons of 36 vitrectomized eyes of 22 diabetics undergoing maintenance HD with those of 138 eyes of 69 nonoperated patients. Serial IOPs were measured before PPV, after PPV/before dialysis, and during dialysis. Serum osmolarity and blood pressure were also recorded.

RESULTS

In 20 of 36 operated eyes (55.6%) and 18 of 138 nonoperated eyes (13.0%) IOP was increased (> or =4 mm Hg) during HD. In the operated group, marked increases (> or =7 mm Hg) were noted in 9 eyes and ocular pain in 5 eyes. Eyes with pre-existing outflow obstruction and/or acute postoperative outflow compromise carried high risks. No correlation with changes in serum osmolarity or blood pressure was found.

CONCLUSION

Monitoring of IOP during HD seems warranted when diabetics with pre-existing outflow obstruction and/or postoperative outflow compromise, undergo HD following PPV.

Increased eyelid pigmentation associated with use of latanoprost

PURPOSE

To report increased eyelid pigmentation as an adverse side effect associated with topical latanoprost.

METHOD

Case report. A 62-year-old Korean woman with normal-tension glaucoma developed bilateral increased eyelid skin pigmentation 4 months after beginning treatment with latanoprost in both eyes. Clinical examinations were performed, and external photographs were taken.

RESULT

Latanoprost was discontinued. Periodic examinations revealed that the eyelid skin pigmentation gradually diminished 1 month after the cessation of the drug, and decrease in pigmentation continued over 4 months of follow-up.

CONCLUSION

An increase in eyelid skin pigmentation is a possible complication of topical latanoprost therapy, and the cessation of the drug can result in loss of induced pigmentation in humans.

Clinical results of Ahmed glaucoma valve implantation in refractory glaucoma with adjunctive mitomycin C

OBJECTIVE

To study the surgical outcome and complications of Ahmed glaucoma valve (AGV) implantation with mitomycin C (MMC) in refractory glaucoma.

PATIENTS AND METHODS

The authors retrospectively reviewed the records of 40 eyes in 37 consecutive patients who underwent combined AGV with MMC (0.4 mg/mL; 5 minutes). All patients had a minimum of 6 months of follow-up. Outcome measures were best corrected visual acuity, intraocular pressure (IOP), the number of medications, success rates, and the incidence of complications.

RESULTS

The Kaplan-Meier life table analysis revealed that the probabilities of surgical success based on our success criteria at 1 year and 2 years postoperatively were 80% and 77%, respectively. Postoperative IOP was significantly lower at all follow-up intervals. At the final visit fewer glaucoma medications were used (2.5 vs 0.7, preoperative vs postoperative). The most frequent complication was hypotony (17%).

CONCLUSION

In this retrospective case series with relatively short follow-ups, AGV implantation with mitomycin C in refractory glaucoma appears to be effective without increased complication rates.

The immediate effect of bilateral superior obliuqe tenotomy on primary position horizontal binocular alignment

PURPOSE

To evaluate the effect on primary position horizontal binocular alignment of superior oblique tenotomy for A-pattern exotropia with bilateral superior oblique overaction using new surgical and anesthesia techniques.

SUBJECTS AND METHODS

We performed intraoperatively adjustable horizontal strabismus surgery under topical anesthesia in 6 cases of A-pattern exotropia. After adjusting the horizontal deviation nearly to orthotropia in primary position, we measured the angle of horizontal deviation in up-, primary, and downgaze positions. This was followed by bilateral superior oblique tenotomy and remeasurement of the horizontal deviation in the same 3 positions. Postoperatively we remeasured the deviation at one day, one month and three months.

RESULTS

There was no immediate change in the horizontal deviation in primary position in 2 of the 6 patients, and 3-8 delta of immediate esotropic shift in 4 of the 6 patients (average 3.3 delta) after bilateral superior oblique tenotomy. At 3 months postop' the small esotropia noted at the immediate postop' measurement became orthotropic. There was a tendency of increased exotropic shift or becoming exotropic in those patients with slight exotropia or orthotropia at the immediate postop' measurement. But these shifts were minimal.

CONCLUSION

When combined surgery of superior oblique and horizontal muscle is planned for A-pattern exotropia, the effect of bilateral superior oblique tenotomy on the primary position horizontal binocular alignment can be disregarded.

Penetrating keratoplasty for pseudophakic bullous keratopathy associated with semiflexible, closed-loop anterior chamber intraocular lenses

We performed penetrating keratoplasty on 32 eyes that developed pseudophakic bullous keratopathy associated with closed-loop anterior chamber intraocular lenses. All lenses were exchanged at the time of keratoplasty. Seventeen patients received anterior chamber intraocular lenses and 15 patients had a posterior chamber lens sutured to the iris or sclera. Postoperatively, 13 of 32 eyes (41%) achieved a visual acuity of 20/100 or better, and 27 of 32 eyes (84%) had a clear graft. A high incidence of cystoid macular edema (eight cases), and graft rejection (seven cases) resulted in marked visual loss.