Ceo_839 lai.fm

Clinical and Experimental Ophthalmology 2004; 32: 368–372
Original Article _____________________________________
Five-year follow up of selective laser trabeculoplasty in Chinese eyes Jimmy SM Lai FRCOphth,1 John KH Chua FRCS,2 Clement CY Tham FRCS2 and Dennis SC Lam FRCOphth2
1Department of Ophthalmology, United Christian Hospital, and 2Department of Ophthalmology and Visual Sciences, The Chinese
University of Hong Kong, Hong Kong, China
ABSTRACT
Purpose:
Selective laser trabeculoplasty in Chinese eyes This randomized, prospective study evaluated the effec- throughout 360° of the TM. Immediately following laser tiveness and safety of SLT compared with medical treatment treatment, one drop of 1% apraclonidine and 1% pred- in patients with POAG or OHT in Chinese eyes.
nisolone acetate were administered to the laser-treated eye.
The prednisolone acetate eye drop was continued at afrequency of 4 times per day for 7 days.
Intraocular pressures of the laser-treated and the fellow The study was approved by the Ethics Committee of the eyes were measured with Goldmann applanation tonometer Chinese University of Hong Kong. Patients newly diag- hourly for 2 h following SLT and continued to be monitored nosed with POAG or OHT were included in the study. All hourly if the rise was more than 5 mmHg. Anterior chamber patients had IOP >21 mmHg in both eyes without anti- reaction was assessed by slit-lamp biomicroscopy. For the glaucomatous medications and those with POAG demon- fellow eyes, topical antiglaucoma medications including - strated optic disc changes and/or visual field changes typical blocker, pilocarpine, dorzolamide and latanoprost were started of glaucomatous damage. Exclusion criteria included previ- either as monotherapy or in combination 2 h after SLT.
ous laser trabeculoplasty, previous intraocular surgery dis- Patients were followed up after 1 day, 1 week, 2 weeks, turbing the aqueous outflow, active ocular inflammation, 1 month, 3 months and 6 months and then yearly after poor visualization of the trabecular meshwork, single eye the laser treatment. During these visits, the following and pregnancy. Written informed consent was obtained parameters were assessed: IOP measured with Goldmann from every patient prior to the study.
applanation tonometer, best-corrected visual acuity by the Patients included in this study were screened twice with standard Snellen chart, slit-lamp biomicroscopy of the an interval of 2 weeks before receiving the laser treatment.
anterior segment, gonioscopy, fundal examination including During the first screening examination, the following were assessment of the cup/disc ratio. The degree of TM pigmen- recorded: IOP measured with Goldmann applanation tation and the presence of peripheral anterior synechiae tonometer, best-corrected visual acuity by the standard Snellen chart, slit-lamp biomicroscopy of the anterior The primary aim of this study was to evaluate the IOP segment, gonioscopy, fundal examination including the lowering effect and safety of SLT. The outcome was ana- assessment of cup/disc ratio and visual field assessment by lysed based on the magnitude of the IOP reduction and the static automated perimetry (Humphrey full-threshold central mean number of medications at yearly follow-up intervals.
Failure was defined as IOP > 21 mmHg on maximal toler- Intraocular pressure measurement with Goldmann appla- nation tonometry was performed at the second screeningexamination. Patients were excluded if the baseline IOP of one eye differed from the fellow eye by more than 15% ateither of the two screening visits. For recruited subjects, IOP A total of 64 eyes of 32 patients were included in the study was measured in two separate visits. The average of the two from March to June 1998 at the Prince of Wales Hospital, measurements was taken as the baseline IOP. One eye of the Chinese University of Hong Kong. Three patients each patient was randomized by computer-generated alloca- defaulted follow up within 6 months of commencement tion schedule to receive SLT (Group 1) and the fellow eyes of treatment and were excluded. Data from the remaining received medical treatment (Group 2). To minimize the 29 patients (58 eyes) were analysed. Twenty-four patients extent of cross-over effect with medical treatment, patients (82.8%) were successfully followed up yearly for a period were instructed to apply digital lacrimal punctual pressure of 5 years. All patients were Chinese with dark brown iris.
for 5 min after instilling the eye drops.
The mean age was 51.9 ± 14.7 years with 13 men and 16 The laser procedure was performed by one surgeon women. Seventeen patients were diagnosed to have POAG (JSML) under topical anaesthesia with proparacaine. One and 12 had OHT. The best-corrected visual acuity ranged drop of 1% apraclonidine was instilled into the eye to receive from 0.1 to 1.0 in group 1 and from 0.2 to 1.0 in group 2.
SLT 1 h prior to treatment. The Selecta 7000 frequency- The mean cup/disc ratio was 0.4 ± 0.2 in group 1 and doubled Q-switched Nd:YAG laser (Coherent, Palo Alto, 0.5 ± 0.2 in group 2 (P = 0.95, Student’s t-test). The mean CA, USA) was used. A 3-mirror Goldmann goniolens was placed on the cornea and the trabecular meshwork was 26.2 ± 4.2 mmHg in Group 2 (P = 0.62, Student’s t-test).
brought into focus using the modified Coherent LDS-10 slit The mean IOP reduction was 8.6 ± 6.7 mmHg (32.1%) lamp with LAS-10 spot mirror illumination.
in group 1 and 8.7 ± 6.6 mmHg (33.2%) in group 2 at the The initial laser energy was set at 0.8 mJ. A single laser 5-year follow-up visit (P = 0.95, Student’s t-test). Figure 1 pulse was delivered starting at the 12 o’clock position. The shows the short and long-term mean IOP reductions after energy was then increased or decreased by 0.1 mJ until treatment in both groups. There was no significant differ- bubble formation became just invisible. Treatment was ence in the mean IOP reductions between the two groups then continued in single-burst mode at this energy level from day 1 to the last follow up at 5 years. In the SLT group, until about 100 non-overlapping laser spots were placed eight eyes (27.6%) required additional medical therapy to Figure 2.
Mean number of medications in (᭜) the selective laser trabeculectomy group and (᭿) the medical treatment group.
P < 0.001 at all time intervals (Student’s t-test).
Figure 1.
(a) Short-term and (b) long-term intraocular pressure (IOP) reductions in (᭜) the selective laser trabeculectomy groupand (᭿) the medical treatment group. P > 0.05 at all time intervals(Student’s t-test).
Figure 3.
Kaplan–Meier curve showing survival probability of control the IOP to below 21 mmHg. One of these eight (᭜) the selective laser trabeculectomy group and (᭿) the medical eyes required supplementary medication as early as 4 weeks after the SLT and the remaining seven eyes only requiredsupplementary medications 1 year after SLT. The meannumber of medications required for IOP control remained carpine, dorzolamide, latanoprost or various combinations significantly lower in the SLT than the medical treatment of them. In the SLT group, the eight patients who required group up to the last follow up at 5 years (P < 0.001, Student’s supplementary medications during 5-year follow up were t-test). Figure 2 shows the mean number of medications at put on topical β-blocker. Two of them required dorzo- various time points. The mean number of medications lamide and one required latanoprost in addition to the required to control the IOP ranged from 0.46 to 0.55 in the SLT group and from 1.45 to 1.63 in the medical treatment The mean laser energy per spot to achieve the endpoint group. The number was significantly lower in the SLT group was 1.0 ± 0.1 mJ. The mean total laser energy used was during the 5-year follow up (P < 0.001).
73.6 ± 16.4 mJ. Transient postlaser IOP spike of greater Five eyes (17.2%) in the SLT group and eight eyes than 5 mmHg was observed in three eyes (10.3%). No (27.6%) in the medical treatment group had IOP >21 mmHg persistent anterior chamber reaction beyond 1 week post- despite maximal medications and required filtration surgery.
laser was recorded. No patients in group 1 had increase in However, the difference in the failure rates defined as IOP TM pigmentation or formation of peripheral anterior syn- >21 mmHg on maximal medications was not statistically echiae as a result of the laser treatment. The mean cup/disc significant (P = 0.53, χ2 test). The Kaplan-Meier curve in ratio at 5 years was 0.5 ± 0.2 in group 1 and 0.5 ± 0.2 in Fig. 3 shows the survival probability of both treatment group 2. There was no statistically significant change com- groups. In the remaining patients, those in the medical pared to the pretreatment ratio. (P = 0.80 group 1, P = 0.78 treatment group were put on either topical β-blocker, pilo- Selective laser trabeculoplasty in Chinese eyes DISCUSSION
Treatment Study.19 We tried to minimize this cross-overeffect by applying lacrimal punctual pressure for 5 min Argon laser trabeculoplasty, introduced by Wise and after administration of eye drops. Ariturk et al. have shown Witter, effectively decreases IOP in patients with POAG1 that occlusion of the nasolacrimal canal by plugging the but the laser energy induces thermal injury in the pigmented punctum significantly increased the IOP reduction effect of TM cells with concurrent damage to the adjacent non- antiglaucoma eye drops but there was no significant change pigmented cells and collagen trabecular beams.4,5 SLT is a in the IOP in the unplugged eyes.20 Nevertheless our results frequency-doubled Q-switched Nd:YAG (wavelength 532 nm) should be interpreted with the potential overestimation of laser system that delivers energy with short pulse duration and low fluence to the target tissues. It selectively targets In conclusion, the IOP lowering effect of SLT in this pigmented TM cells without coagulative damage to the group of Chinese patients with POAG or OHT is effective.
adjacent tissues, and histological studies showed minimal SLT significantly reduces the number of antiglaucoma damage in the trabecular beams and endothelial cells in eyes medications required for IOP control. Its IOP lowering effect is fast in onset and is maintained in the majority of We adopted the regimen of using 1% apraclonidine 1 h cases up to 5 years. Immediate postlaser IOP spike and before and immediately after SLT. Only three eyes (10.3%) persistent anterior chamber reaction were minimized by the had increased IOP >5 mmHg within 2 h after laser treat- use of apraclonidine and short-term topical steroid, respec- ment. These three patients were monitored hourly and the tively. Long-term excessive angle scarring in the form of IOP came down to <5 mmHg of baseline within 4 h after peripheral anterior synechiae was not noted. The overall laser treatment. The incidence is lower than the ALT series clinical response was similar to reported series in non- reported in the Glaucoma Laser Trial Research Group (34%)16 and the SLT series reported by Latina et al. (24%).12The mean laser energy per spot required to reach the end-point in our pigmented eyes was similar to that required in REFERENCES
non-Asian eyes. No persistent anterior chamber reaction 1. Wise JB, Witter SL. Argon laser therapy for open-angle glau- beyond 1 week postlaser was recorded with the use of coma. Arch Ophthalmol 1979; 97: 319–22.
2. Moriarty AP, McHugh JDA, Spalton DJ, Ffytche TJ, Shah SM, From our study, the mean IOP in Group 1 of the SLT- Marshall J. Comparison of the anterior chamber inflammatory treated eyes started to decrease by 4.0 mmHg (14.9%) 2 h response to diode and argon laser trabeculoplasty using a laser after treatment before antiglaucoma medication was given flare meter. Ophthalmology 1993; 100: 1263–7.
to the fellow eye. It continued to drop by 10.8 mmHg 3. Kwasniewska S, Fankhauser F, Larsen SE, Cruz-Orive LM. The (40.3%) on day 1 but the decrease in IOP became less efficacy of cw Nd:YAG laser trabeculoplasty. Ophthalmic Surg dramatic after the first week and became stabilized after the 1993; 24: 304–8.
4. Bylsma SB, Samples JR, Acott TS, Van Buskirk EM. Trabecular first month with a reduction of 8.3 mmHg (31.0%) (Fig. 1a).
cell division after argon laser trabeculoplasty. Arch Ophthalmol The immediate IOP response to SLT in our group of 1988; 106: 544–7.
patients was similar to that reported by Lanzetta et al.13 5. Rodrigues MM, Spaeth GL, Donohoo P. Electron microscopy Damji et al. also reported immediate IOP reduction 1 h after of argon laser therapy in phakic open-angle glaucoma. Oph- SLT and ALT.14 They also showed that SLT was equivalent thalmology 1982; 89: 198–210.
to ALT in lowering the IOP in the first 6 months after 6. Fink AI, Jordan AJ, Lao PN, Fong DA. Therapeutic limitations treatment. In Group 2, the mean IOP decreased by of argon laser trabeculoplasty. Br J Ophthalmol 1988; 72: 263–9.
7.4 mmHg (28.2%) on day 1 but the magnitude became less 7. Schwartz AL, Love DC, Schwartz MA. Long-term follow-up after the first week and stabilized after the first month with of argon laser trabeculoplasty for uncontrolled open-angle a reduction of 7.7 mmHg (29.4%) (Fig. 1a).
glaucoma. Arch Ophthalmol 1985; 103: 1482–4.
The IOP lowering effect of SLT was maintained for 8. Hoskins HD, Hetherington J, Minckler DS, Lieberman MF, 5 years in the majority of cases. Only 13 eyes required the Shaffer RN. Complications of laser trabeculoplasty. Ophthal- addition of antiglaucoma medications for control of IOP, of mology 1983; 90: 796–9.
which more than 90% occurred at least 1 year after SLT.
9. Wilensky JT, Weinreb RN. Early and late failures of argon Out of these 13 eyes, eight had IOP controlled below laser trabeculoplasty. Arch Ophthalmol, 1983; 101: 895–7.
10. Rouhiainen HJ, Terasvirta ME, Tuovinen EJ. Peripheral 21 mmHg and five required filtration surgery. In the medical anterior synechiae formation after trabeculoplasty. Arch Oph- group, eight eyes with failed maximal medical treatment thalmol 1988; 106: 189–91.
required filtration surgery. Our results in terms of IOP 11. Feldman RM, Gross RL, Spaeth GL et al. Risk factors for the reductions, number of medications reduction and the failure development of Tenon’s cysts after trabeculoplasty. Ophthal- rate compare favourably with other SLT studies.12–15,17,18 mology 1989; 96: 336–41.
The major flaw of this study is the evaluation of the 12. Latina MA, Sibayan SA, Shin DH, Noecker RJ, Marcellino G.
effects of SLT and medications on the same patient. The Q-switched 532-nm Nd:YAG laser trabeculoplasty (selective contralateral effect of topical beta-adrenergic antagonists laser trabeculoplasty): a multicenter, pilot, clinical study. Oph- was reported to be significant in the Ocular Hypertensive thalmology 1998; 105: 2082–8.
13. Lanzetta P, Menchini U, Virgili G. Immediate intraocular 17. Glaucoma Laser Trial Research Group. The Glaucoma Laser pressure response to selective laser trabeculoplasty. Br J Oph- Trial (GLT). I. Acute effects of argon laser trabeculoplasty on thalmol 1999; 83: 29–32.
intraocular pressure. Arch Ophthalmol 1984; 107: 1135–42.
14. Damji KF, Shah KC, Rock WJ, Bains HS, Hodge WG.
18. Glaucoma Laser Trial Research Group. The Glaucoma Laser Selective laser trabeculoplasty versus argon laser trabeculo- Trial (GLT). 2. Results of argon laser trabeculoplasty versus plasty: a prospective randomized clinical trial. Br J Ophthalmol topical medicines. Ophthalmology 1990; 97: 1401–2.
1999; 83: 718–22.
19. Piltz J, Gross R, Shin DH et al. Contralateral effect of topical 15. Melamed S, Simon GJB, Lvkovitch-Verbin H. Selective laser β-adrenergic antagonists in initial one-eyed trials in the trabeculoplasty as primary treatment for open-angle glaucoma.
Ocular Hypertension Treatment Study. Am J Ophthalmol 2000; A prospective, nonrandomized pilot study. Arch Ophthalmol 130: 441–53.
2003; 121: 957–60.
20. Ariturk N, Oge I, Erkan D, Sullu Y, Sahin M. The effects of 16. Latina MA, Park C. Selective targeting of trabecular meshwork nasolacrimal canal blockage on topical medications for glau- cells. in vitro studies of pulsed and CW laser interactions. Exp coma. Acta Ophthalmol Scand 1996; 74: 411–13.
Eye Res 1995; 60: 359–72.

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