|Year : 1991 | Volume
| Issue : 3 | Page : 87-90
Argon laser iridoplasty : A primary mode of therapy in primary angle closure glaucoma
HC Agarwal, Rakesh Kumar, VK Kalra, NN Sood
Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All Institute of Medical Sciences, Ansari Nagar, New Delhi, India
H C Agarwal
Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All Institute of Medical Sciences, Ansari Nagar, New Delhi
Source of Support: None, Conflict of Interest: None
Argon laser iridoplasty was performed in 40 eyes of 33 patients of primary angle closure glaucoma. There were 12 male and 21 female patients. The mean ages of the male and female patients were 51 years and 48.4 years respectively. Forty eyes were divided into two groups. Group I consisted of ten eyes of subacute angle closure glaucoma and group II included thirty eyes of chronic angle closure glaucoma. Argon laser iridoplasty was performed with Coherent 9000 model using laser settings of spot size 200 micron, duration 0.2 second and power 0.7 watt. A total of 80 spots were applied over 360 degree circumference. The intraocular pressure control (below 22 mm Hg) was achieved after iridoplasty in all the eyes (100%) in group I, where as in group II the intraocular pressure was controlled in 70% eyes. The follow up period varied from 3 months to one year with a mean of eight months. The success rate with iridoplasty was directly related to the extent of peripheral anterior synechiae, optic disc cupping and presence of visual field changes.
|How to cite this article:|
Agarwal H C, Kumar R, Kalra V K, Sood N N. Argon laser iridoplasty : A primary mode of therapy in primary angle closure glaucoma. Indian J Ophthalmol 1991;39:87-90
| Introduction|| |
Since the time of Albrecht Von Graefe (1857), surgery has been the treatmert of choice in cases of primary angle closure glauco a . However, recent advances in lasers have revo utionised the management of primary angle closure glaucoma. Argon laser and Nd. Yag laser iridotomy is a safe substitute for surgical iridectomy ,,,, Argon laser iridoplasty which causes flattening of the peripheral iris and widening of the anterior chamber angle, has been tried as an alternative mode of therapy in primary angle closure glaucoma [7, 8, 9, 10]sub . It is generally effective when there is an appositional angle closure and when : early peripheral anterior synecniae are formed . The results and associated complications of argon laser iridoplasty as a primary ierapy for primary angle closure glaucoma in Indian population are being reported here.
| Material and methods|| |
40 eyes of 33 patients of primary angle closure glaucoma from the glaucoma clinic are the subject of this study. These eyes were divided it o 2 groups:
Group I Subacute angle closure glaucoma (10 eyes)
Group II Chronic angle closure glaucoma (30 eyes)
Ila Peripheral anterior synechiae /= 180 osub with optic disc cupping upto 0.5 (12 eyes)
Ilb Peripheral anterior synechiae 180 osub with
optic disc cupping 0.5 (17 eyes)
A detailed history with particular reference to attacks of pain, redness, watering of eyes and coloured halos were taken. Examination of each eye included best spectacle corrected visual acuity, slit lamp examination, optic disc evaluation by direct ophthalmoscopy, Goldmann applanation tonometry, gonioscopy with Goldmann single mirror gonioscope and visual field charting by Goldmann kinetic perimetry. The diagnosis of subacute angle closure glaucoma was established on the basis of history of coloured halos, intermittent closure of angle and rise of IOP, while chronic angle closure glaucoma on the basis of presence of PAS, persistent rise of IOP with and without field changes.
Pilocarpine nitrate 2% drops three times atday was advised topically. In addition timolol maleate 0.5% drops twice a day was instituted if intraocular pressure could not be reduced upto 22 mm Hg with pilocarpine nitrate alone. Acetazolamide, oral glycerol and mannitol intravenously in usual doses were given, whenever required.
A written consent for the laser treatment was obtained from all the patients. After constricting the pupil with pilocarpine 2% drops three times at 5 minutes intervals, topical anaesthesia was obtained by instillation of 4% Xylocaine drops in the cul de sac. The patient was positioned on Coherent blue-green argon laser 900. Goldmann three mirror lens was applied using methyl-cellulose 2% as fluid bridge to visualise the anterior chamber angle structures. Argon laser burns were applied 1-1.5 mm. away from the root of the iris in a 360 degree circumference. We used a spot size of 200 u, duration 0.2 sec. and intensity of 0.7 watt. A total of 80 spots were applied, appreciation of angle structures was taken to be the end point.
After the laser procedure, the patients were advised topical betamethasone eye drops 4 times a day for 5 days, in addition to pretreatment with antiglaucoma medication. The antiglaucoma treatment was adjusted during subsequent follow up visits till the intraocular pressure was stabilised below 22 mm Hg with minimum local medical therapy. Slit lamp examination and applanation tonometry were carried out after laser therapy at 1 hour, 2 hour, 3 hour and 24 hour intervals. Subsequently, these patients were followed up at 1 week, 2 week, 4 week, 8 week and 12 week intervals. During each follow up, visual acuity, slit lamp examination, optic disc evaluation, applanation tonometry and gonioscopy were carried out. All patients were followed up for a minimum period of 3 months and maximum of one year duration.
| Results|| |
Forty eyes of thirty three patients of primary angle closure glaucoma were included in this study. There were 12 male and 21 female patients of age group 35-75 years, with a mean of 51 years in males and 48.4 years in females. There were 10 eyes in group I (subacute angle closure glaucoma) and 30 eyes in group II (chronic angle closure glaucoma).
The intraocular pressure was below 22 mm Hg after laser iridoplasty in all the ten eyes in group I. Seven eyes (70%) did not require any treatment. Three eyes (30%) required only 2% pilocarpine nitrate drops topically.
Thirty eyes in group II were divided into two subgroups. Out of thirteen eyes in subgroup Ila, having closed angle with peripheral anterior synechiae 180 o, optic cup disc ratio 0.5, the intraocular pressure remained below 22 mm Hg in 4 eyes (30.76%) without medication and eight (61.52%) eyes required topical pilocarpine nitrate 2% drops three times a day alone or in combination with timolol maleate 0.5% twice a day. One eye was subjected to surgery. Of the seventeen eyes in group Ilb, having closed angle with peripheral anterior synechiae 180 o, optic cup disc ratio 0.5 none of the eyes were controlled without medication, nine eyes (52.95%) required pilocarpine nitrate 2 % three times a day alone or in combination with timolol maleate 0.5% twice a day. The rest of eight (47.5%) eyes remained uncontrolled with topical antiglaucoma medical therapy and were subjected to surgery. The control of intraocular pressure was achieved in all the eyes (100%) in group I, 92.28% in group Ila and 52% in group Ilb either without medication or with topical antiglaucoma medication [Table - 6].
On comparing the control of intraocular pressure with reference to the field changes, it was observed that out of 12 eyes with normal visual field, (4 eyes (33.33%) were. controlled without medication, 7 eyes (58.33%) required topical antiglaucoma medication and one eye was subjected to surgery, while out of 18 eyes with glaucomatous field defects none were controlled without medication. 10 (55.5%) eyes required topical antiglaucoma medication and 8 (45.5%) eyes were subjected to surgery [Table - 4].
Early postoperative rise of IOP was observed in 17 (40.25%) eyes. The elevation of IOP was more marked in eyes having peripheral anterior synechiae more than 180 o (Scatter diagram I, II). The other complications observed following argon laser iridoplasty are as in [Table - 5].
| Discussion|| |
Laser iridotomy is considered to be the treatment of choice in cases of primary angle closure glaucoma ,,,. Scattered studies are available where argon laser iridoplasty has been tried as a primary modality of treatment but no mention of type of primary angle closure glaucoma and its correlation with PAS, disc and field changes and complications has been made ,,. Alternatively, argon laser iridoplasty which causes stretching of the peripheral iris leading to widening of the anterior chamber angle has been tried in such cases ,,,. Iridoplasty is generally effective. in presence of appositional angle closure and in eyes with early peripheral anterior synechiae of short duration. The effect is often less permanent . Carpel and Brown (1983) reported permanent effect of iridoplasty in a patient of plateau iris configuration using argon laser heavy burns.
The results of this study indicate that out of 10 eyes of subacute angle closure glaucoma, the control of intraocular pressure (below 22 mm Hg) could be achieved without subsequent topical antiglaucoma medication in 7 (70%) eyes and only 3 (30%) eyes required topical pilocarpine nitrate. Out of 30 eyes of chronic angle closure glaucoma, intraocular pressure was controlled without medication in 4 (13.3%) eyes and 17 (56.66%) eyes were controlled with topical antiglaucoma medication. Nine (30%) eyes were subjected to surgery. Thus 13.33% of eyes were controlled without medication and 13% eyes required less topical medication in the post-laser period [Table - 1].
On comparing the control of intraocular pressure in the subgroups of chronic angle glaucoma (group Ila - peripheral anterior synechiae 180 o, CD ratio :1 and group Ilb with PAS 180 o, CD ratio 0.5:1) it was found that out of 13 eyes in group Ila, 4 (30.76%) eyes were controlled without medication, 8 (61.52%) eyes required additional medical therapy, while in group Ilb, none of the eyes were controlled without medication and 9 (52.95%) eyes were controlled with medical therapy and 8 (47.05%) eyes were subjected to surgery [Table - 6]. The follow up of our cases varied from a minimum of 3 months to one year with a mean of eight months.
It shows that argon laser iridoplasty is more effective in cases of primary angle closure glaucoma in the subacute stage as compared with the chronic stage. The success of iridoplasty in the chronic stage depends upon the extent of PAS, the degree of optic disc cupping and vist)al field changes. The lesser these changes, the better the chances of success of iridoplasty.
The early post-laser rise of intraocular pressure was seen in 17 (42.5%) eyes and it ranged from 10 mm Hg to 34 mm Hg with a mean of 20.42±4.45. The increase of pressure was more marked in group Ilb and was statistically significant (Scatter diagram I and II). This may be explained on the basis of compromised outflow facility of aqueous already existing in these eyes. The post-laser rise of intraocular pressure was managed medically without any sequelae. There were no serious and permanent complications following the procedure. It is recommended that cases of subacute angle closure glaucoma and chronic angle closure glaucoma with PAS 180 o, CD ratio and normal fields may be safely subjected to argon laser iridoplasty as an alternative to surgery. However, the procedure may be deferred in eyes with PAS 180 o, CD ratio 0.5 and in presence of advanced glaucomatous field defects. A prospective study of a larger number of patients with a longer follow up is being undertaken.
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[Table - 1], [Table - 2], [Table - 3], [Table - 4], [Table - 5], [Table - 6]