Alvin K H Kwok

Indocyanine green assisted retinal internal limiting membrane removal in stage 3 or 4 macular hole surgery

Aims: To determine surgical outcome in primary idiopathic stage 3 or 4 macular holes with indocyanine green (ICG) assisted retinal internal limiting membrane (ILM) peeling. Methods: A prospective, consecutive, interventional case series with 41 eyes of 40 patients was included. No patient defaulted follow up. Besides a standard macular hole surgery, all eyes received ICG assisted ILM removal of 3–4 disc diameters around macular holes. At the end of the surgery, 12% perfluoropropane gas was used. A face down posture for 2 weeks was required postoperatively. Results: The mean follow up period was 15.1 months (range 6–24 months). Twenty (48.8%) eyes had stage 3 macular holes and 21 (51.2%) had stage 4 macular holes. The overall median duration of holes was 11 months. 19 (46.3%) were chronic macular holes of more than 12 months’ duration. The anatomical success rates after one surgery was 87.8% (36 eyes), while that of chronic and non-chronic ones was 78.9% and 95.5%, respectively. The median preoperative and postoperative visual acuity was 20/200 (range 20/60 to counting fingers) and 20/100 (range 20/20 to 20/400), respectively. 24 (58.5%) eyes had improvement of two or more Snellen lines. The mean was 3.2 lines (range two to nine lines), with 3.6 lines and 2.7 lines for non-chronic and chronic holes, respectively. For all the 41 eyes, 16 (39%) eyes had a final visual acuity of 20/50 or better. Conclusion: ICG assisted retinal ILM removal, in idiopathic primary chronic and non-chronic stage 3 or 4 macular hole surgery, appears to give a promising anatomical closure rate without compromising the visual result.

Ocular-hypertensive Response to Topical Steroids in Children

OBJECTIVE The purpose of the study is to investigate the rate and degree of ocular-hypertensive response to topical steroids in Chinese children. DESIGN The study design was an institutional, randomized, clinical trial. PARTICIPANTS A total of 19 consecutive patients were studied. INTERVENTION Topical steroids were administered to Chinese children younger than 10 years of age who underwent bilateral strabismus surgery. One eye was randomized to receive topical 0.1% dexamethasone (DMS), whereas the fellow eye received 0.1% fluorometholone (FML) six times per day for up to 4 weeks. Intraocular pressure (IOP) was measured on the day before operation and at postoperative days 1, 3, 6, 10, 13, and 27, then every 2 weeks thereafter until the IOP fell to preoperative levels. Topical steroids would be stopped if IOP was 30.00 mmHg or greater. MAIN OUTCOME MEASURES Peak IOP and maximal change of IOP from baseline were measured and categorized into low, intermediate, and high levels. Time to peak IOP also was studied. RESULTS A total of 16 patients were included. The peak IOP for DMS-treated eyes was 30.66 +/- 8.35 mmHg (range, 13.00-48.00 mmHg), whereas that in FML-treated eyes was significantly lower at 20.66 +/- 6.03 mmHg (range, 11.30-36.30 mmHg) (P = 0.001). The maximal change in IOP ranged from -2.60 to +31.00 mmHg in DMS-treated eyes (mean, 15.48 +/- 8.71 mmHg), almost double that of FML-treated eyes (range, +1.00 to +17.00 mmHg; mean, 5.83 +/- 4.96 mmHg) (P = 0.001). When the ocular-hypertensive responses of both DMS and FML groups were categorized into three levels of severity, significant differences were found between the two treatment groups (P = 0.001). In the DMS group, nine patients (56.25%) were high responders and six patients (37.5%) were intermediate responders. In the FML group, only one patient (6.25%) was a high responder. CONCLUSIONS The ocular-hypertensive response to topical DMS in children occurs more frequently, more severely, and more rapidly than that reported in adults. A total of 56% of the studied children, all younger than 10 years of age, were high responders to topical DMS. Of these, 89% attained their peak IOP within 8 days. Its use in children should best be avoided if possible. It would be desirable to monitor the IOP when it is being used. Conversely, FML produced a much less ocular-hypertensive effect and therefore poses an acceptable risk of clinically significant pressure elevation.

Vitrectomy and gas tamponade without internal limiting membrane peeling for myopic foveoschisis

Aim: To evaluate the clinical and anatomical outcomes of pars plana vitrectomy and gas tamponade without internal limiting membrane (ILM) peeling in symptomatic patients caused by myopic foveoschisis. Methods: Nine eyes in eight highly myopic patients who had myopic foveoschisis with foveal detachment underwent vitrectomy without ILM peeling followed by gas tamponade. Main outcome measures include change in best corrected visual acuity (BCVA) and changes in height of the foveal detachment and resolution of the myopic foveoschisis measured by optical coherence tomography (OCT). Results: After surgery, BCVA improved in eight eyes with the median BCVA improved from 20/80 to 20/50 (p = 0.012). The mean line of visual improvement was 3.6 lines. OCT showed complete resolution of myopic foveoschisis with complete foveal reattachment in seven (77.8%) eyes with partial resolution in two (22.2%) eyes. The mean height of foveal detachment decreased from 505 μm preoperatively to 21 μm postoperatively (p<0.001). Conclusions: Vitrectomy without ILM peeling followed by gas tamponade appeared to result in favourable visual and anatomical outcomes for treating myopic foveoschisis in highly myopic eyes. The results are comparable with studies in which ILM removal was performed. Further controlled study will be useful to determine the role of ILM peeling in these patients.

Photodynamic therapy with verteporfin for subfoveal idiopathic choroidal neovascularization: one-year results from a prospective case series.

OBJECTIVE To study the safety and efficacy of photodynamic therapy (PDT) with verteporfin in treating subfoveal choroidal neovascularization (CNV) of idiopathic cause. DESIGN A prospective, noncomparative, consecutive, open-label, two-center, interventional case series. PARTICIPANTS Patients aged 50 years or younger with the diagnosis of idiopathic CNV by exclusion of other related causes together with the CNV extending under the geometric center of the foveal avascular zone. METHODS Seventeen eyes from 17 patients received PDT with verteporfin according to a standardized protocol. Retreatment was considered if fluorescein leakage from the CNV was shown in fluorescein angiography at every 3-month follow-up. The visual, clinical, and angiographic responses were observed. Complications from treatment were monitored and documented. MAIN OUTCOMES MEASURES The changes in the best-corrected visual acuity (BCVA) at the 1-year follow-up. The proportion of patients with improved (gained 2 lines or more), stable, and dropped (lost 2 lines or more) vision and the mean number of treatments required during the 1-year interval were measured. Complications were monitored and tabulated. RESULTS Seventeen eyes with complete 1-year follow-up were analyzed. The mean logarithm of the minimum angle of resolution BCVA improved from 0.64 to 0.41 (Wilcoxon signed-ranks test, P = 0.007). Sixteen eyes (94%) had stable or improved vision. Only one patient (6%) had moderate loss of vision. The mean number of PDT treatment was 1.8 per eye over the 1-year period. Patients with smaller lesion size or active vascular CNV on presentation were more likely to have a final BCVA of 20/100 or better (Fishers exact test, P = 0.006 and P = 0.015, respectively). No serious local or systemic complications were encountered. CONCLUSIONS PDT seems to be a promising treatment strategy in achieving a stable or improved vision for subfoveal idiopathic CNV. The treatment was well tolerated. Further studies and longer follow-up are warranted to assess the long-term safety and efficacy of PDT compared with observation or other treatment modalities.

Epiretinal membrane formation with internal limiting membrane wrinkling after Nd:YAG laser membranotomy in valsalva retinopathy

PURPOSE To report the location of premacular hemorrhage in Valsalva retinopathy and epiretinal membrane formation with internal limiting membrane (ILM) wrinkling after neodymium;yttrium-aluminum-garnet (Nd:YAG) laser membranotomy. DESIGN Interventional case report. METHODS A 35-year-old man with a massive premacular hemorrhage due to Valsalva retinopathy underwent Nd:YAG laser membranotomy. After membranotomy, his visual acuity improved from 20/200 to 20/25. Ten months later, he developed metamorphopsia with visual acuity of 20/30. A semiopacified membrane with radiating striae was found, and pars plana vitrectomy was performed for membrane removal. RESULTS Histologic examination of the membrane showed hemosiderin deposits within macrophages on the retinal side of the ILM. One year later, the patient was asymptomatic with visual acuity of 20/20. CONCLUSIONS To our knowledge, histopathologic confirmation of the sub-ILM hemorrhage in Valsalva retinopathy and epiretinal membrane formation with ILM wrinkling as a complication after Nd:YAG laser membranotomy have not been previously reported.

Ocular hypertensive response to topical dexamethasone in children : A dose-dependent phenomenon

OBJECTIVE To investigate the ocular-hypertensive response to different dosages of topical dexamethasone eye drops in Chinese children. DESIGN Prospective, randomized clinical trial. PARTICIPANTS Thirty-one consecutive children undergoing bilateral strabismus surgery. INTERVENTION Topical dexamethasone (0.1%) was administered to children undergoing bilateral strabismus surgery. They were all less than 10 years of age. One eye was randomized to receive a regimen of four times daily, and another received a twice daily regimen. Intraocular pressure (IOP) was serially measured in the postoperative period for 4 weeks or more. Topical steroids were discontinued if IOP was 30 mmHg or more. MAIN OUTCOME MEASURES Intraocular pressure was measured on the day before the surgery, on postoperative days 1, 3, 5, 8, 12, 15, 22, 29, and 2 weeks thereafter until the IOP reached preoperative levels. Peak IOP, IOP net increase, and time to reach an IOP more than 20 mmHg in the two study groups were analyzed. RESULTS A total of 31 patients (20 male, 11 female) were examined. The mean age was 5.8 +/- 2.0 years (range, 2-10 years). Preoperative IOP in groups treated twice daily and four times daily were similar. After topical dexamethasone treatment, both groups showed a significant rise in peak IOP compared with preoperative values (twice daily, 25.2 +/- 6.8 mmHg vs. 14.3 +/- 2.4 mmHg, P < 0.001; four times daily, 28.7 +/- 6.9 mmHg vs. 14.3 +/- 2.9 mmHg, P < 0.001). The peak IOP was significantly higher in the four times daily group (P < 0.001), as was the net increase in IOP (twice daily, 10.9 +/- 5.8 mmHg vs. four times daily, 14.5 +/- 6.4 mmHg; P < 0.001). There was no difference in time for both groups to achieve the peak IOP, but the time to exceed its upper normal value (20 mmHg) was shorter in the four times daily group (twice daily, 12.3 +/- 9.1 days vs. four times daily, 10.0 +/- 7.4 days; P < 0.05). CONCLUSIONS In children treated with topical dexamethasone, ocular hypertension occurs in a dose-dependent manner. Children in the four times daily group had a quicker onset and more severe ocular hypertensive response than the twice daily group. Nevertheless, even the twice daily regimen produced significant IOP rise, suggesting that dexamethasone use in children should be avoided if possible, and it would be desirable to monitor the IOP twice weekly when it is administered to children.

Presence of crystalline lens as a protective factor for the late development of open angle glaucoma after vitrectomy.

Purpose: To evaluate the late development of open angle glaucoma (OAG) after vitrectomy and to compare the rate of postvitrectomy OAG development in phakic and pseudophakic eyes. Methods: Retrospective case series of 101 eyes of 101 patients who had vitrectomy for idiopathic epiretinal membrane or idiopathic macular hole with a follow-up duration of more than 6 months. Eligible patients were assessed for new development of OAG during the follow-up period. Patients were separated into two groups based on the lens status at the end of the vitrectomy for statistical analysis using Kaplan–Meier survival analysis with log-rank test and Cox regression analysis. Results: The mean follow-up duration was 51 months (range, 6–80 months). Of the 101 eyes, 8 (7.9%) eyes developed OAG during the follow-up period. Phakic eyes were less likely to develop OAG after vitrectomy compared with pseudophakic eyes, with 2% and 13%, respectively (log-rank test, P = 0.025). The result remained statistically significant after adjustment for age, refractive error and the use of gas tamponade (adjusted odds ratio = 0.09, P = 0.038). Conclusion: The presence of the crystalline lens may be protective against the late development of OAG after vitrectomy.

Endolaser around macular hole in the management of associated retinal detachment in highly myopic eyes.

Purpose: To analyze the role of endolaser around macular hole in managing associated retinal detachment in patients with high myopia. Methods: Review of medical records of 25 consecutive eyes of 25 patients with at least 5.00 diopters of myopia who underwent primary pars plana vitrectomy and fluid‐gas exchange. In the first half of the study period, one row of contiguous argon green endolaser was routinely applied over the retinal edge of the macular hole (EL group). In the second half of the study period, endolaser was not applied around any macular hole (NEL group). Demographic information, intraoperative and postoperative complications, and final visual acuities and retinal reattachment rates were studied. Results: The mean (±SD) refractive error was ‐11.8 ± ‐3.5 diopters (D) for the EL group and ‐11.6 ± ‐5.4 D for the NEL group. The mean axial length was 29.0 ±1.8 mm for the EL group and 28.3 ± 1.7 mm for the NEL group. The primary anatomic success was 62.5% (10/16) and 77.8% (7/9) in the EL and NEL groups, respectively. No statistically significant difference was found in preoperative, postoperative, or change in best‐corrected visual acuities between the two groups. Conclusion: Endolaser around the macular hole after pars plana vitrectomy and internal gas tamponade may not affect the anatomic or visual outcome in primary retinal detachment secondary to a highly myopic macular hole. RETINA 20:439‐444, 2000

Ultrasound biomicroscopy of conventional and sutureless pars plana sclerotomies: a comparative and longitudinal study ☆

PURPOSE To report the rate of ultrasonically visible vitreous incarceration and longitudinal changes of incarcerated vitreous in pars plana sclerotomies after conventional suturing or sutureless technique using ultrasound biomicroscopy. METHODS Twenty-five consecutive eyes (25 patients) undergoing primary three-port pars plana vitrectomy participated. The first 16 pars plana vitrectomies were performed with standard conventional sutured sclerotomies, and the following nine pars plana vitrectomies were performed with modified sutureless sclerotomies. Patient demographics, diagnoses, procedures, and complications were recorded. Each patient had ultrasound biomicroscopy performed 1 week before surgery, and also after surgery at 1 week, 2 weeks, 3 weeks, 4 weeks, 2 months, 3 months, and 6 months. Visible vitreous incarceration was graded as 0 to 3. RESULTS Vitreous incarceration was seen in 41 of 48 sclerotomies (85.4%) in the conventionally sutured group, and in 23 of 27 sclerotomies (85.2%) in the sutureless group, with no significant difference in severity among sclerotomies within each group and between the two groups. There was a significant difference in the rate of vitreous incarceration between diabetic patients with proliferative retinopathy and others (P =.002). No progressive change of visible vitreous incarceration was noted in any eye during the 6-month postoperative period. No sclerotomy-related complications occurred during the study period. CONCLUSIONS Ultrasound biomicroscopy showed no difference in the amount of visible vitreous incarceration in conventionally sutured or sutureless sclerotomies. There was no visible longitudinal change in the incarcerated vitreous during the 6 months of follow-up in uncomplicated cases.

Trypan blue- and indocyanine green-assisted epiretinal membrane surgery: clinical and histopathological studies.

AbstractPurpose To evaluate the clinical outcome and electron microscopic findings of trypan blue (Tb) and indocyanine green (ICG) assisted epiretinal membrane (ERM) surgery.Methods This is a prospective consecutive noncomparative interventional case series. After pars plana vitrectomy, 0.1 ml of 0.6 mg/ml Tb solution was applied for 1 min under air for ERM staining. After ERM removal, internal limiting membrane (ILM) was further peeled after staining with 0.2 ml of 1 mg/ml ICG solution. Intraoperative specimens were sent for electron microscopy. Tb was considered useful if the edge of ERM was stained where peeling could be initiated with a clearer visualisation of the overall extent of the ERM.Results In all, 16 eyes from 16 patients were recruited. There were nine grade 1 ERMs, five grade 2 ERMs, and two grade 3 ERMs. Tb was useful in six (67%) of the nine eyes with grade 1 ERMs and in all eyes with grade 2 or 3 ERMs. The three remaining grade 1 ERMs were removed together with surrounding ILM that was stained by ICG. The mean line of improvement was 1.3 lines with the median BCVA improved from 6/12 to 6/9. All 16 eyes had symptomatic improvement and none developed ERM recurrence. No complication related to Tb or ICG was observed clinically or angiographically. Electron microscopy of the Tb-stained ERM specimens showed fragments of ILM in all specimens.Conclusions Tb and ICG are useful intraoperatively to improve the visualisation and facilitate complete removal of ERM and ILM in macular ERM surgery.