1. Kocabeyoglu S*, Bezci F*, Mocan MC*, Irkec M*
Effectiveness of Transcleral Diode Laser Cyclophotocoagulation in Patients with Glaucoma
Kocabeyoglu S*, Bezci F*, Mocan MC*, Irkec M*
*Hacettepe University, Faculty of Medicine, Department of Ophthalmology, Ankara, Turkey
P-WT-165
Introduction
Destruction of the ciliary body using various methods is among the limited options for the management of refractory glaucoma where conventional medical and or surgical modalities fail to adequately control intraocular pressure (1-3). TS-CPC has been established to be an alternative thereupatic modality to tube shunt or augmented trabeculectomy for refractory glaucoma especially in eyes with poor visual acuity (4). In addition, response rateds to this treatment modality has been different depending on the underlying glaucoma with higher success rates attained in primary open angle glaucoma (POAG), neovascular glaucoma (NVG) and inflammatory glaucomas compared with congenital, juvenile, traumatic and glaucoma following cataract surgery (i.e. aphakic glaucoma). (5) Despite the widespread use of TS-CPC, published reports reveal that treatment centers vary significantly with respect to their laser energy delivery and postoperative management schemes. Thus, analysis of data from standardized treatment protocols may help refine the TS-CPC technique with potentially improved outcomes and reduced adverse effects.
Purpose
The main purpose of the current study was to evaluate the efficacy and safety of TS-CPC limited to 180° of ciliary body ablation in patients with various forms of refractory glaucoma.
Material and Methods
Thirty eyes of 30 patients who underwent diode laser cyclophotocoagulation due to glaucoma were recruited in this retrospective study. Patient’s age, gender, the type of glaucoma, the number of diode laser treatment, pre- and post-laser intraocular pressure (IOP) values, success rate of diode laser, postoperative complications, number of anti-glaucomatous medication and best corrected visual acuity (BCVA) were evaluated. Surgical success criteria were additional laser and/or topical treatment, and reduction more than %20 or to be below 21 mmHg for IOP values.
Results
The mean follow-up period was 22.2 ± 16.5 months (6-60 months) after the first cyclodiod laser application. The diagnosis of the patients was congenital glaucoma in 5 (16.6%), juvenile glaucoma in 2 (6.6%), neovascular glaucoma in 9 (30%), primary open-angle glaucoma in 3 (10%), traumatic glaucoma in 2 (6.6%), exfoliative glaucoma in 3 (10%), uveitic glaucoma in 1 (3.3%), endothelial dysgenesia in 1 (3.3%), glaucoma after keratoplasy in 1 (3.3%), and aphakic glaucoma in 3 patients (10%). The mean preoperative IOP was 39.3 ± 10.2 mmHg. The overall successful IOP reduction was found to be in 20 patients (66%). The rate of IOP decline in successfully treated patients was 43.8 % after the first treatment and 46.7% after the second treatment. Hypotony (6,6%) and hyphema (6,6%) occurred in two patients. Phytisis bulbi developed in one patient (3,3%) who had hyphema after the treatment. Uveitis, retinal detachment and sympathetic ophthalmia were not found in any patient. Decrease in BCVA due to diode laser application was observed in 2 patients.
Discussion
In our study, the percentage of successfully treated eyes was found to be 86 % at the end of 2 years follow up. A significant decrease was observed in the IOP values in the majority of the studies in the literature. Murphy et al. (2) found this value %52.6 and Singh et al. found %58.5 (1). The reason for being different from the literature may be that our follow-up period (22.2 months) was longer than the others, 17 months and 9 months respectively.
Second laser treatment was needed 53.5% of patients. The majority of this group is juvenile glaucoma, congenital glaucoma and neovascular glaucoma. Also it was not statically significant, recurrent laser need was found more frequently in the young age group as mentioned by Threlkeld et al, the cause can be attributed to the fact that younger aqueous production is stronger and / or tissue healing is better (7). In 6.6% of the patients, VA due to cyclodiode administration was decreased by one Snellen line. In the study conducted by Mistlberger et al, two or more Snellen line decreased was reported at 18.7 % while in the study of Spencer et al 32%. (2, 7). The reason for this difference may be due to the low number of patients we include and the low pre-op visual acuity of the patients in this study.
Since cyclodiode laser energy use is not standardized, it is difficult to compare it with other studies on equal terms. There was a significant correlation between the total amount of energy and the success in some studies (4-6).
In conclusion, transscleral diode laser cyclophotocoagulation is a non-penetrating and reproducible method, which can be safely used in patients with glaucoma. Effective reduction in IOP can be achieved in resistant glaucoma with a low complication rate without a significant decrease in visual acuity.
Table 1. Glaucoma type of patients (N=30)
Glaucoma category
Number of eyes(%)
Congenital
5 (16.6%)
Juvenile
2 (6.6%)
Primary open angle
3 (10%)
Neovascular
9 (30%)
Uveitic
1 (3.3%)
Traumatic
Post-keratoplasty
Pseudoexfoliation
ICE syndrome
Aphakic
Table2. Number of second and third laser application to glaucoma types
Glaucoma Types
Second laser application
( N= 16)
Third laser application
( N= 4)
Congenital
4 ( 25%)
2 ( 50%)
Neovascular
1 ( 25%)
Juvenile
2 ( 12.5%)
Pseudoexfoliation -
Aphakic
1 ( 6.25%)
Uveitic
Traumatic
Post keratoplasty
Table 3. Mean IOP value, glaucoma medication number and total energy levels of each types
Glaucoma types
Mean pre- laser IOP (mm Hg) (SD)
Mean post- laser IOP (mm Hg) (SD)
Mean pre- laser drug number (SD)
Mean post- laser drug number (SD)
Mean total energy(J)
(SD)
Aphakic
36.6± 11.0
32.0± 7.9
2.0± 2.0
40.4± 17.8
Congenital
36.6± 4.7
27.4± 8.5
2.8± 1.3
2.0± 1.5
53.0± 21.5
NVG
Juvenile
44.1± 9.2
45.5± 14.8
20.5± 6.1
30± 5.6
2.6± 1.1
3.0± 0.1
2.3± 1.2
1.5± 2.1
70.9± 44.5
59.1± 35.2
POAG
34.0± 6.5
22.6± 8.9
3.0± 1.0
29.8± 11.4
PEG
32.0± 4.5
19.0± 7.9
3.6± 0.5
4.0± 1.0
44.2± 26.8
Uveitic
49.0± 9.8
30.0± 18.3
3.0± 1.4
2.5± 0.7
106.1± 22.7
Traumatic
34.0
26.0
3.0
2.0
99.4
Dysgenesis
32.0
13.0
22.5
Post keratoplasty
35.0
17.0
67.5
All eyes
39.2± 8.9
23.9± 8.5
2.8± 1.0
2.4± 1.3
58.9± 34.7
References
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Zhekov I, Janjua R, Shahid H, Sarkies N, Martin KR, White AJ. A retrospective analysis of long-term outcomes following a single episode of transscleral cyclodiode laser treatment in patients with glaucoma. BMJ open. 2013; 3(7): e
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Threlkeld AB, Johnson MH. Contact transscleral diode cyclophotocoagulation for refractory glaucoma. Journal of glaucoma. 1999; 8(1): 3-7.
The authors have no proprietary interest in any of the materials used in this study.