Visual outcome and complications after Nd-YAG laser capsulotomy in patients with posterior capsular opacification.
Background: Cataract remains the most common treatable cause of blindness in the developing world including Pakistan. Posterior capsular opacification is a natural consequence of extra capsular cataract extraction and phacoemulsification.
Objectives: To see complications during and after Nd-YAG laser capsulotomy and evaluate the visual outcome in aphakic and pseudophakic patients with posterior capsular opacification.
Patients and Methods: The study was conducted on consecutive aphakic and pseudophakic patients suffering from posterior capsular opacification who were admitted for Nd-YAG laser capsulotomy at Ophthalmology Department of Saidu Teaching Hospital, Saidu Sharif, Swat, from November 2006 to May 2007.
Results: Out of 45 cases, 28(62.2%) were males and 17(37.8%) females. The mean age was 56 years and the mean time interval between cataract surgery and Nd-YAG capsulotomy was 31.2 months. Fifty eyes of 45 patients with posterior capsular opacification underwent Nd-YAG laser capsulotomy, of which 27(54%) were right and 23(46%) were left sided. Twenty nine (58%) eyes had capsular fibrosis, 14(28%) had Elschnig pearls, 6(12%) had both capsular fibrosis and Elschnig pearls and one (2%) eye had capsular wrinkling. Damage to intraocular lens in two eyes and corneal burn in one eye were procedural complications. Post-laser complications were raised intraocular pressure in 7 eyes, corneal oedema and anterior uveitis in two eyes each. Twenty five (50%) eyes had visual acuity of 6/60 or less before capsulotomy. The visual acuity after Nd-YAG laser capsulotomy was 6/60 or less in 15(30%) eyes. Four (8%) eyes had good pre-laser visual acuity of 6/6-6/12; while 14(28%) eyes had post laser visual acuity of 6/6-6/12.
No case had further deterioration of visual acuity after Nd-YAG laser capsulotomy.
Conclusions: Capsular fibrosis is the commonest presentation of posterior capsular opacification. Damage to intraocular lens and corneal burn were encountered during procedure. Majority of patients had significant improvement in visual acuity. Raised intraocular pressure, corneal oedema and iritis were seen as post laser complications.
Key words: Nd-YAG capsulotomy, cataract, posterior capsule opacification.
Corresponding Author: Abid Naseem Saidu Medical Centre Saidu Sharif Swat.
Cataract is the most common treatable cause of blindness in the developing world. In Pakistan the situation is not different and according to Pakistan National Blindness and Visual Impairment Survey almost 75% of blind individuals had treatable cause of blindness i.e.un-operated cataract in 51.5% cases of blindness1 and more than 12% of blindness was due to the sequalae of cataract surgery i.e uncorrected aphakia 8.6% and posterior capsular opacification3.6%.2
Posterior capsular opacification is a natural consequence of extra capsular cataract extraction and phacoemulsification. Some workers have reported an incidence of late onset posterior capsular opacification after extra capsular cataract extraction and posterior chamber intraocular lens implantation ranging from 18 to 50% in patients followed for 5 years.3 Due to opacification, there is gradual deterioration of visual functions which ultimately leads to decreased visual acuity, decreased contrast sensitivity, glare or even monocular diplopia.4,5 The posterior capsular opacification develops in months to years postoperatively. In younger age groups it develops earlier but in elderly people, its incidence declines.6 Since, the use of neodymium-doped yttrium aluminium garnet; Nd: Y3Al5O12 (Nd-YAG) laser for posterior capsulotomy, this procedure has been gradually replacing surgical capsulotomy7 as it is less invasive, safe and can be performed as an outpatient's procedure.
The aim of the present study was to see the complications occurring during and after Nd-YAG laser capsulotomy in aphakic and pseudophakic patients with posterior capsular opacification and see immediate visual outcome as visual acuity.
Patients and Methods
This study was conducted on consecutive patients suffering from posterior capsular opacification admitted to the Ophthalmology Department of Saidu Teaching Hospital, Saidu Sharif, Swat. All patients over the age of 7 years admitted for Nd-YAG laser capsulotomy for posterior capsular opacification from November 2006 to May 2007 were included in the study. Patients having posterior capsular opacification with either capsular fibrosis and/ or Elschnig pearls or capsular wrinkling seen on slit lamp examination before and after pupillary dilatation, those having aphakic or pseudophakic eyes were included in the study. Excluded were cases undergoing Nd-YAG laser capsulotomy for therapeutic purpose and patients with thick posterior capsule where Nd-YAG laser capsulotomy would was not possible.
Informed consent was obtained from all participants before entry into study. A separate data collecting proforma was filled for every patient. After taking history, all patients were evaluated clinically. Pre-laser visual acuity, slit lamp examination and intraocular pressure were recorded. The type and extent of posterior capsular opacification was noted after pupillary dilatation. Patients underwent Nd-YAG laser capsulotomy under topical anesthesia. The parameters of laser system were adjusted according to the need of the patients, depending upon the type and extent of posterior capsular opacification. As capsulotomy was done for optical purpose its size was restricted to 2-3 mm in diameter.
All operative complications were recorded. Topical non-steroidal anti inflammatory drops four times daily and topical beta blocker twice daily were advised and patients were rested. First post-operative day visual acuity and intraocular pressure were measured and patients were discharged after recording the post operative complications. Visual acuity on 1st post-operative day was also compared with pre-operative visual acuity. The data were analyzed using SPSS (Ver.11).
Forty five patients aged seven years and above, admitted for Nd-YAG laser capsulotomy for optical purpose were studied. Among these 28 (62.2%) were males and 17 (37.8%) were females. The mean age of the patients was 56 years (SD+-18.56); the youngest patient was 7 years old while the oldest patient was 90 years of age. Median and mode age was 60 years Figure-1. Five patients had bilateral posterior capsular opacification, while 40 patients had unilateral posterior capsular opacification; out of which 22 (48.8%) were right and 18 (40%) were left sided. Mean time interval between cataract surgery and Nd-YAG capsulotomy was 31.2 months (SD+- 38.57) with a median time of 21 months and mode of 12 months (Range 1-206 months).
Fifty eyes of 45 patients with posterior capsular opacification underwent Nd-YAG laser capsulotomy of which 27(54%) were right while 23(46%) were left sided. Forty five (90%) eyes had posterior chamber intraocular lens, two (4%) had anterior chamber intraocular lens while three (6%) eyes were aphakic. Pre-operative visual acuity is given in Figure-2.
CF= Counting Finger, HM= Hand Movement, PL= Perception of Light.
Figure 2: Pre-Laser visual acuity of patients.
Pre-operative intraocular pressure ranged from 10-50 mm Hg (mean 15.71 mm Hg (SD+-5.96). median 15 mm Hg, mode 16 mm Hg). Twenty nine (58%) eyes had capsular fibrosis, 14(28%) had Elschnig pearls, six (12%) had both capsular fibrosis and Elschnig pearls and one eye had capsular wrinkling. Ocular co-morbidities are given in Table-1.
The energy was delivered as single pulse in all cases. An average of 28.7 (SD+- 22.2) shots were given to produce appropriate size of capsulotomy. Median number of shots were 22.5 and mode was 10, with a range (5-120)shots.
Table 1: Ocular Co-morbidities.
Co-morbidity:###No. of cases###Percentage
Raised Intraocular Pressure###3###6
Displaced Intraocular lens###2###4
AC Intraocular lens###2###4
AC= Anterior Chamber
Mean energy per shot was 2.6mj (SD+-0.824). Median energy per shot was 2.3mj, mode was 2mj, while range of energy per shot was 4.2mj (1.8-6). Complete capsulotomy was achieved in all cases in single session. Mean total energy delivered was 74.5mj (SD+-62.18). Median total energy was 49.4mj, mode was 30.7mj, while range of total energy delivered was 268mj (10-278). Procedural complications encountered were damage to intraocular lens in two eyes and corneal burn in one eye while post operative complications were raised intraocular pressure in 7(14%) eyes, corneal oedema in two eyes and anterior uveitis in two eyes.
CF= Counting Finger, HM= Hand Movement, PL= Perception of Light.
Figure 3: Post Laser Visual Acuity.
Mean intraocular pressure on 1st post-operative day was 16.81 mm Hg (SD+-8.37) with median of 14 mm Hg and mode 12 mm Hg, range was 36(8-44) mm Hg. Visual acuity was checked on 1st post-operative day and is given in Figure 3. Pre and post-laser visual acuities are compared in Table-2. It was seen that 25(50%) eyes had visual acuity of 6/60 or less before capsulotomy. The visual acuity after Nd-YAG laser capsulotomy was 6/60 or less in 15(30%) eyes. Four (8%) eyes had good pre-laser visual acuity of 6/6-6/12; while 14(28%) eyes had post laser visual acuity of 6/6-6/12. None had further deterioration of visual acuity after Nd-YAG laser capsulotomy.
Table 2: Comparison of Visual Acuities.
Visual Acuity###Pre Laser###Post Laser
###No. of cases###%###No. of cases###%###
6/6 - 6/12###4###8###14###28
6/18 - 6/36###20###40###18###36
6/60 - CF###21###42###13###26
HM - PL###4###8###2###4
CF= Counting Finger, HM= Hand Movement, PL= Perception of Light.
The procedure of Nd-YAG in posterior capsulotomy was first described by Deniele Aron- Rosa8 and is the most easily performed YAG procedure. These days surgical capsulotomy is being rapidly replaced by the Nd-YAG laser capsulotomy. Nd-YAG laser is a photodisruptive laser, producing extreme heat of about 10,0000C along with acoustic shock wave at the site of focus. The technique is now used in ophthalmology to perform capsulotomy, peripheral iridotomy in glaucoma and to cut vitreous bands.9,10
In the present study, male predominance was seen Tayyab and colleagues also reported male predominance in one group of patients while equal gender distribution was seen in their another study.11 In a national study also male dominance was seen12 and Hasan, et al also reported same gender ratio.6
The time period between cataract surgery and Nd-YAG laser capsulotomy was 31.2 months in the present study while it was 23 months in one study,12 2.49 years in another6, and 24 months in a national study.13 In the present study capsular fibrosis was the commonest type of posterior capsular opacification followed by Elschnig pearls. Younas et al12 reported capsular fibrosis as the predominant type of posterior capsular opacification while Hasan et al6 reported Elschnig pearls in pseudophakic and secondary fibrosis in aphakic eyes.
There was dramatic improvement in visual acuity on snellen chart, after Nd-YAG laser capsulotomy and 25(50%) eyes showed visual acuity of 6/60 or less before laser while 15(30%) eyes had visual acuity of 6/60 or less after laser. Our study also showed that 4(8%) eyes had good pre-laser visual acuity of 6/6-6/12; while 14(28%) eyes had post laser visual acuity of 6/6-6/12. No patient had further deterioration of visual acuity after Nd-YAG laser capsulotomy. In a study by Younas et al12 53.4% eyes had visual acuity of 6/60 or less before laser; while 13.8% eyes had visual acuity of 6/60 or less after laser. Similarly 6.8% eyes had good pre-laser visual acuity of 6/6-6/12; while 32.6% had post laser visual acuity of 6/6-6/12, with no further deterioration of visual acuity in any case. A similar study reported improvement of visual acuity of one or more snellen's lines in 56 out of 63 eyes.13
In another study pre laser visual acuity was observed between hand movement and 6/36 in 80% of cases and post laser visual acuity attained was between 6/18-6/6 in 91% cases.14 All these studies reported that there was definite improvement in visual acuity in high percentage of patients after Nd-YAG laser treatment and none reported deterioration of visual acuity after laser treatment. Nd-YAG laser has been accepted as standard technique for treating posterior capsular opacification7 resulting in rapid visual improvement and similar findings were found in the present study. Visual loss from posterior capsular opacification will increase as cataract surgery increases; therefore, YAG laser needs to be made available in hospitals conducting large number of cataract surgeries.2
Complications encountered in our study like damage to intraocular lens, corneal burn, raised intraocular pressure, corneal oedema and anterior uveitis were all recognized complications of Nd-YAG laser capsulotomy and had been reported previously.15-20 In two eyes the intraocular lens was damaged due to pitting, caused by improper focusing of YAG laser along with non-cooperative patients who move their eyes during procedure. In another study 7.7% cases had intraocular lens damaged.14 In our study only one (2%) eye had corneal burn which was due to incorrect focusing of YAG laser; compared to three (3.8%) cases reported in another study.14 In the present study seven (14%) eyes had raised intraocular pressure after laser which was treated with beta blocker antiglaucoma eye drops, which normalized the pressure within few days but the treatment was continued for further two weeks.
In another study five (6.4%) cases had raised intraocular pressure after laser capsulotomy14 while in the present study two (4%) eyes had corneal oedema and two (4%) had mild anterior uveitis on 1st post laser day.
Capsulotomy with Nd-YAG laser should not be performed in un-cooperative patients who cannot maintain a steady position on slit lamp.
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*Present Address: Department of Ophthalmology, Khyber Institute of Ophthalmic Medical Sciences Lady Reading Hospital, Peshawar.2
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|Author:||Naseem, Abid; Rahman, Faizur; Rashid, Haroon; Mohammad, Tariq; Saidu, Saeed; Sharif, Saidu|
|Publication:||Pakistan Journal of Medical Research|
|Date:||Jun 30, 2010|
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