Developmental glaucoma is a disease for which surgery should be performed as early as possible. The disease may be bilateral in two-thirds of the patient population and approximately 50% of the patients present with variably opaque media precluding the possibility of goniotomy. Early clearance of corneal oedema is essential for the infant’s visual development and several investigators have suggested that surgery can be performed as early as the first few days or weeks of life.
Is simultaneous bilateral surgery for developmental glaucoma justified? In adults, simultaneous bilateral intraocular surgery is rarely undertaken due to the perceived risk of endophthalmitis, which can be visually devastating. However, there are several reports of simultaneous bilateral glaucoma surgery in infants and children to avoid monocular deprivation during a critical period of visual development as well as to minimise the risk of anaesthesia, despite the danger of endophthalmitis. On the other hand, a survey of 500 paediatric ophthalmologists and glaucoma specialists by Wheeler et al did not recommend simultaneous bilateral paediatric intraocular surgery.
Recently, we reported a large series of 120 patients of developmental glaucoma of which 45 patients underwent simultaneous bilateral primary combined trabeculotomy-trabeculectomy without any sight-threatening complications. The current study was undertaken to evaluate the safety and efficacy of simultaneous bilateral primary combined trabeculotomy-trabeculectomy in a series of 109 consecutive patients who underwent the same procedure by a single surgeon over a 10-year period in a tertiary eye-care center in India.
Materials and Methods
We reviewed the charts of children who underwent consecutive simultaneous bilateral primary combined trabeculotomy-trabeculectomy from January 1990 through December 1999. The choice of simultaneous bilateral surgery was offered to all patients after a thorough discussion of the risks and benefits. All surgeries were performed by a single surgeon (AKM). Informed consent was obtained from parents of all patients, and the use of simultaneous bilateral combined trabeculotomy-trabeculectomy as the primary therapeutic modality was approved by the Ethics Committee for Human Research at the L.V.Prasad Eye Institute.
Patients with developmental glaucoma were identified based on the classification system of Hoskins et al: congenital (existing at or usually before birth); infantile (occurring from birth until age 2 years); and juvenile (age 2 years or older).
A definite protocol for evaluation and management of children with developmental glaucoma as described by us was followed. In short, it consisted of measurement of IOP with a Perkin’s hand-held applanation tonometer in the early phase of inhalation anaesthesia using 1% halothane. The IOPs were measured using Goldmann applanation tonometer in children who were cooperative enough for a slitlamp examination. Examination of cornea under high magnification was performed to determine its clarity and the horizontal and vertical diameters.
Technique of anaesthesia
The induction of anaesthesia was done with oxygen, nitrous oxide and sevoflourane through a face mask. After securing the intravenous line, maintenance of anaesthesia was done with oxygen, nitrous oxide and vecuronium or with atracurium, fentanyl and glycopyrrolate. Monitoring was done with oxygen saturation (SPO2), ECG, temperature, heart-rate, and blood pressure. Intermittent positive pressure ventilation was done throughout the anaesthesia and an electric blanket was used to maintain a comfortable temperature. The reversal of anaesthesia was done with injection atropine and neostigmine.
Using a computerised data entry proforma, all preoperative, surgical and postoperative parameters were entered. Any intra- and perioperative surgical complications and re-treatments were duly recorded.
The outcome measures included preoperative and postoperative IOPs, corneal clarity and diameters, visual acuities, success rate, bleb characteristics, time of surgical failure and complications. The incidence of any complication and anaesthetic morbidity and mortality were analysed.
The surgical technique employed in all cases was primary combined trabeculotomy-trabeculectomy. This technique has been described by us earlier. In short, the Schlemm’s canal was dissected under a partial thickness limbal-based triangular scleral flap and trabeculotomy ab externo was performed on both sides of the radial incision. Trabeculectomy was then performed in the usual manner. After completion of surgery on the first eye, the second eye was operated using similar technique but with a new set of instruments, drapes, drops, gown, gloves, etc., simulating a surgical procedure on a different patient.
All patients were treated with topical 1% cyclopentolate twice daily for one month and with the corticosteroid-antibiotic preparation (0.1% betamethasone and neomycin) six times a day, tapered gradually over a 6-week period. All patients were examined 1, 2, and 3 days after surgery, followed by examination in the office at the end of 1, 3, and 6 weeks and every 3 months thereafter. At each visit, patients were examined with a slitlamp biomicroscope, and the anterior chamber depth, corneal appearance, IOP, bleb appearance, and fundus picture (drawing) were documented. Patients who did not cooperate for office examination were scheduled for examination under anaesthesia at the end of 1, 3, and 6 weeks and every 3 months thereafter.
Surgical success and failure were defined before data analysis. Complete success was defined as IOP less than 16 mmHg under general anaesthesia or less than 21 mmHg without anaesthesia and when there was no progression of disc cupping and corneal diameter. Qualified success was defined as the maintenance of such pressure with a single topical antiglaucoma medication (timolol maleate 0.25% twice daily) or ocular hypotony (IOP less than 5 mmHg) without visual loss. Failure was defined as IOP greater than 16 mmHg under general anaesthesia; IOP greater than 21 mmHg without general anaesthesia; IOP less than 21 mmHg with hypotony-related maculopathy; and other sight-threatening complications.
Results are expressed as mean ± standard deviation (SD). Statistical analysis was performed to determine significant differences in IOP using the Chi-square test. P < 0.05 was considered statistically significant. Cumulative success probability was determined using Kaplan-Meier survival analysis.
A total of 218 eyes of 109 patients were included in the study. Information regarding age, gender, diagnosis and follow-up are listed in [Table - 1]. The mean age at presentation was 6.8 ± 12.7 months (range, 3 days - 84 months; median, 3 months). The study population predominantly had congenital glaucoma (166 eyes, 76.1%). All patients were of Asian origin. The male to female ratio was 1.4: 1. The mean follow-up was 16.33 ± 16.2 months.
The preoperative and postoperative IOP recordings are listed in [Table - 1]. The mean preoperative IOP was 26.4 ± 5.9 mmHg (range, 8 - 42 mmHg). Although some of the patients had normal IOP, the decision for surgical intervention was taken because they were on antiglaucoma medications and the diagnosis of glaucoma was confirmed based on the total evaluation of the eye. On the last follow-up visit, the IOP was 13.5 ± 4.5 mmHg (range, 2 - 34 mmHg). The percentage reduction of IOP was 46.2 ± 23.7 (P < 0.0001). Preoperatively, 124 patients were on antiglaucoma medications (mean 1.2). At the last follow-up IOP was controlled in 158 (86.3%) of 183 eyes. Of these, 145 (91.8%) eyes were without any antiglaucoma medication. In the remaining 13 (8.2%) eyes, IOP was controlled with one medication, (timolol maleate 0.5% twice daily). Twenty-five (13.7%) of 183 eyes had IOP >16 mmHg. Of these, 20 (80%) eyes were not controlled even with one medication and were considered failures.
Corneal diameter and clarity
Mean (± SD) horizontal corneal diameters were 12.5 ± 1.2 mm (range, 10 - 16 mm), 13.5 ± 10.8 mm (range, 11.5 - 15 mm) and 12.7 ± 1.7 (range 11.5 - 18 mm) in the congenital, infantile and juvenile groups respectively. The mean corneal diameter across the 3 groups was 12.7 ± 1.23 mm (range, 10-18 mm). The corneal diameters were significantly different between the three groups (P< 0.0001). The multiple comparison test revealed that the corneal diameter of the congenital group was significantly lower than that of the infantile group (P = 0.0001).
At presentation, of the 218 eyes, 17 (7.8%) eyes had clear cornea, Haab’s striae with corneal scarring was present in 35 (16.1%) eyes and 166 (76.1%) eyes had corneal oedema. Postoperative corneal clarity status was not available in 5 eyes. Of the remaining 161 eyes, corneal oedema cleared in 93 (57.8%) eyes (P< 0.0001).
[Figure - 1] shows the clinical appearance of both eyes with corneal oedema in a 3-day-old child with congenital glaucoma. [Figure - 2] demonstrates complete clearing of corneal oedema in both eyes of the same child at the age of 4 years.
Clinically, well functioning blebs (i.e. diffuse low to moderately elevated, relatively avascular with microcystic changes) were present in 114 of 171 (66.6%) eyes. In 57 of 171 (33.3%) eyes the bleb was flat and appeared non-functional clinically.
Majority of the patients belonged to the congenital group; they were preverbal and hence fixation response only could be determined. Preoperative visual acuity was not available for most of the patients. Postoperatively, 100 of 172 (58.1%) eyes in the preverbal age group had steady fixation with an ability to follow the target. The final Snellen visual acuity ranged from 6/60 to 6/15 in 8 of 28 (28.6%) eyes and better than 6/15 in 12 of 28 (42.9%) eyes. In 8 of 28 (28.6 %) eyes, the final visual acuity was worse than 6/60.
Success probabilities were 90.9%, 88% and 69.3% obtained at first, second and third year respectively. [Figure : 3] depicts the Kaplan-Meier survival curve of the patients. The success probability of 69.3% obtained at third year was maintained till 6 years of follow-up. However, only 6 patients have completed 5 years of follow-up. One patient followed up for a longer period had further increase in the IOP (> 16 mmHg) and became a failure, with reduced survival probability after 6 years. Her IOP was well controlled with 0.5% timolol maleate and she was thus later considered a qualified success.
There was no sight threatening intraoperative and postoperative complication. The anterior chambers were shallow in 18 (8.37%) eyes and formed spontaneously in 12 (66.6 %) of them. Six eyes required surgical reformation of anterior chamber; in these eyes a small air bubble was injected into the anterior chamber. There were no serious complications such as retinal detachment, choroidal haemorrhage, late bleb leakage, blebitis and endophthalmitis in any patient over the follow-up period.
Apnea occurred in 17 (15.6%) patients who were successfully resuscitated. The most serious anaesthetic complication was cardio-pulmonary arrest that occurred 5 hours postoperatively following aspiration during feeding in one child who could not be resuscitated. Two children had delayed recovery (2 and 4 hours respectively) because of prematurity (weight at surgery was 2.2 and 2.3 kg respectively). Both children were shifted to the paediatric intensive care unit. The child with 2 hours delayed recovery did well and has completed 3 years of follow-up; the other child expired 48 hours later.
The first step of management of developmental glaucoma aims at normalising IOP without any medication. There has been much debate about the choice of surgery for surgical management of developmental glaucoma. The most compelling argument in favour of primary combined trabeculotomy-trabeculectomy in the Indian patient population is the higher incidence of successful control of IOP with a single procedure already reported by us. Recently, we reported the safety and efficacy of this procedure on a large series of 182 eyes of 120 patients. The success rate of the present series is comparable to other published reports of primary combined trabeculotomy-trabeculectomy published from other parts of the world. To our knowledge, the current study includes the largest number of patients in whom simultaneous bilateral primary combined trabeculotomy-trabeculectomy was performed.
In India, congenital glaucoma is more frequent and more severe than in other parts of the world. Over 80% of our patients present with severe cloudy cornea at birth and goniotomy is technically impossible. Whether primary combined trabeculotomy-trabeculectomy is superior to trabeculotomy or trabeculectomy alone is debatable. In a small series of seven Arab Bedouin infants with congenital glaucoma, Biender and Rothkoff observed no difference between trabeculotomy and combined trabeculotomy-trabeculectomy. Dietlein et al investigated the outcome of trabeculotomy, trabeculectomy and a combined procedure as initial surgical treatment in primary congenital glaucoma. Although combined procedure seemed to have a favourable outcome, the advantages of this procedure over trabeculotomy or trabeculectomy was not statistically significant after 2 years. Elder compared primary trabeculectomy with combined trabeculotomy-trabeculectomy and found the combined procedure superior. The results of the present study are comparable to that reported by Elder and better than the results of goniotomy, trabeculotomy or trabeculectomy alone. The superior results of combined procedure may be because of dual outflow pathway. Mullaney et al and Al-Hazmi et al used mitomycin-C in primary combined trabeculotomy-trabeculectomy and noted greater surgical failure with higher doses of mitomycin-C. Our results are comparable to Mullaney et al but we do not use mitomycin-C in primary surgery.
Usually the surgical prognosis is poor in patients who are born with glaucoma, i.e, in the newborn variety of developmental glaucoma. Shaffer suggested early surgery in the first week of birth in order to improve the chances of cure in these difficult cases. This involves general anaesthesia with its attendant risks in these tiny patients. Since the disease is bilateral in two thirds of the patient population, is it worthwhile to perform simultaneous bilateral surgery to avoid another long anaesthesia? On the other hand, simultaneous bilateral intraocular surgery is controversial. There are few reports of simultaneous bilateral surgery in infants and children with developmental glaucoma to minimize the risk of anaesthesia. Despite the danger of endophthalmitis some authors have suggested bilateral goniotomy during the same anaesthesia. In these series, no intra and postoperative complications including anaesthesia-related ones were reported. Endophthalmitis after any intraocular surgery is a possibility although rare. There is no reason to believe that the possibility of infection following intraocular surgery in children is less common than in adults. Probably it has been reported only rarely. The first documented report of endophthalmitis after cataract surgery in children is by Good et al in 1990. Interestingly, the first report of simultaneous surgery for bilateral congenital cataracts appeared in the same year by Guo et al. Considering the risk of bilateral endophthalmitis which may be sight threatening, Kushner felt that it safer to perform two separate surgical procedures in infants with bilateral congenital cataracts. Wheeler et al have reported an incidence estimate of 0.071% (7 cases per 10,000) of endophthalmitis following intraocular surgery in paediatric patients. This is similar to that recently reported following extracapsular cataract extraction in adults. There was no incidence of endophthalmitis in the present series. Endophthalmitis is a rare complication, and our experience of 0 in 109 patients is compatible with a true rate of up to 3% statistically (0 to 3.4% with confidence interval of 95%).
Despite the risk of bilateral infection following simultaneous bilateral surgery in children, there are several reports on simultaneous surgery for bilateral paediatric cataracts. Simultaneous bilateral cataract extraction is not routinely performed in adults and is controversial. There are several reports of simultaneous bilateral cataract surgery and phacoemulsification in adults. There are reports of endophthalmitis following simultaneous bilateral cataract surgery. To our knowledge, the only reported series of simultaneous trabeculectomy in adults was by Hugkulstone et al and there were no infections in this series. Similarly, despite the possibility of bilateral corneal infection and endophthalmitis, simultaneous bilateral Laser in Situ Keratomileusis (LASIK) has been advocated. Warring et al and Gimbell et al reported that the outcome and complications of simultaneous bilateral LASIK were not different from those of sequential treatments.
The benefits of operating on both the eyes in children in the same surgical session are many. It is more cost-effective for the family; there is efficient use of time for the surgeon; reduced risk of repeated general anaesthesia and finally reduced chance of visual deprivation during the critical period of visual development of the child. Certainly, without the danger of bilateral sight-threatening complications leading to bilateral blindness, bilateral simultaneous surgery would be preferable in these small children. Although reduction of cost is important, it should not became the deciding factor in decision-making process of simultaneous or sequential bilateral surgery. The most important deciding factor for simultaneous bilateral surgery in these tiny patients are the advantages of one anaesthesia versus two and it should be balanced against other possible risks.
There are several reports of general anaesthesia related morbidity and mortality in eye surgery in children’s hospital. There have been several advances in the field of anaesthesiology during the last decade that have reduced the morbidity and mortality in adults as well as in children. Romano and Robinson reviewed the anesthetic morbidity and mortality from the hospital records of 2,422 consecutive cases of eye surgery at a children’s hospital over a period of 10 years. There was no mortality and no permanent morbidity. Reversible morbidity was found in 11.6% of cases, with an attack rate of 12.9%. Tiret et al reported the results of a prospective survey of anesthesia related mortality and morbidity in infants and children. A total of 40,240 anaesthesias were administered to patients younger than 15 years, 2103 (5%) involving infants younger than one year. The risk of complications was significantly higher (P < 0.001) in infants (4.3 per 1000) than in children (0.5 per 1000). In children, circulatory failure was as frequent as respiratory failure and complications were observed almost equally during induction and maintenance and on recovery. The incidence was also higher with previous history of anaesthesia. Respiratory failure during anaesthesia is a major risk factor in infants and the risk increases with a history of previous anaesthesia, with intubation and with an upper respiratory infection. It has been recognized that most cardiac arrests are also due to unrecognized hypoxemia. Evidence suggests that infants are more vulnerable to anaesthesia related complications than older children by a factor of 3 to 8. The infants differ more from children than do children from adults. In our series, anesthetic morbidity included apnea in 17 children; all patients were successfully resuscitated. Anesthesia related mortality occured in two children and another child had delayed recovery (4 hours) because of prematurity. There is no published study comparing the risk of more than one anaesthesia with that of prolonged anaesthesia time. All the three anaesthesiologists involved in this series expressed the view that they would feel comfortable in continuing anaesthesia for completion of surgery on the second eye rather than risking another anaesthesia within a few weeks. A similar view was expressed by the anaesthesiologists in the report by Zwaan.
In conclusion, primary combined trabeculotomy-trabeculectomy is successful in patients with all types of primary developmental glaucoma. In deciding upon simultaneous bilateral surgery, the possible risk of sight-threatening complications including the possibility of bilateral endophthalmitis has to be balanced against the advantages of one anaesthesia versus two, cost effectiveness and simultaneous bilateral early visual rehabilitation. The available literature does not allow a formal comparison between the risks involved in multiple anaesthesia and the possible risk of bilateral endophthalmitis. We did have some major anaesthesia-related complications in some cases, but there was no instance of endophthalmitis. We leave the decision to the reader and glaucoma surgeons. However, based on the results of our study, we conclude that simultaneous bilateral primary combined trabeculotomy-trabeculectomy for developmental glaucoma is safe and effective. This offers several benefits to the patients and to the parents. The decision making process must involve the treating surgeon, the parents and the anaesthesiologists.
Source of Support:
Conflict of Interest:
1. deLuise VP, Anderson DR. Primary infantile glaucoma.(|jCongenital glaucoma) Surv Ophthalmol. 1983;28:1–19
2. Shaffer RN. Prognosis of goniotomy in primary infantile glaucoma (trabeculodysgenesis) Trans Am Ophthalmol Soc. 1982;80:321–25
3. Shaffer RN, Hoskins HD. Montgomery lecture. Goniotomy in the treatment of isolated trabeculodysgenesis (primary congenital [infantile] developmental glaucoma) Trans Ophthalmol Soc UK. 1983;103:581–85
4. Hoskins HD Jr, Shaffer RN, Hetherington J. Goniotomy vs trabeculotomy J Pediatr Ophthalmol Strabismus. 1984;21:153–58
5. Litinsky SM, Shafer RN, Hetherington J, Hoskins HD. iOperative complications of goniotomy Trans Am Ophthalmol Oto. 1977;83:78–79
6. Anderson DR. Trabeculotomy compared to goniotomy for glaucoma in children Ophthalmology. 1983;90:805–6
7. Anderson DR. iIn discussion:Quigley HA. Childhood glaucoma:results with trabeculotomy and study of reversible cupping Ophthalmology. 1982;89:219–25
8. Wheeler DT, Stager DR, Weakley DR Jr. Endophthalmitis following pediatric intraocular surgery for congenital cataracts and congenital glaucoma J Pediatr Ophthalmol Strabismus. 1992;29:139–41
9. Mandal AK, Naduvilath TJ, Jayagandhan A. Surgical results of combined trabeculotomy-trabeculectomy
for developmental glaucoma Ophthalmology. 1998;105:974–82
10. Hoskins HD Jr, Shaffer RN, Hetherington J. Anatomical classification of the developmental glaucomas Arch Ophthalmol. 1984;102:1331–36
11. Mandal AK. Current concepts in the diagnosis and management of developmental glaucomas Indian J Ophthalmol. 1993;41:51–70
12. Stamper RL, Lieberman MF, Drake MV. Other outflow surgeries and surgical techniques. Chapter 39 Becker-Shaffer's Diagnosis and Therapy of the Glaucomas. 19997th ed C. V. Mosby Company St.Louis:668
13. Mandal AK. iPrimary combined trabeculotomy-trabeculectomy
for early onset glaucoma in Sturge-Weber syndrome Ophthalmology. 1999;106:1621–27
14. Elder MJ. Combined trabeculotomy-trabeculectomy
compared with primary trabeculectomy for congenital glaucoma Br J Ophthalmol. 1994;78:745–48
15. O'Connor G. Combined trabeculotomy-trabeculectomy
for congenital glaucoma Br J Ophthalmol. 1994;78:735
16. Mullaney PB, Selleck C, Al-Awad A, Al-Mesfer S, Zwaan J. Combined trabeculotomy and trabeculectomy as an initial procedure in uncomplicated congenital glaucoma Arch Ophthalmol. 1999;117:457–60
17. Al-Hazmi A, Zwaan J, Awad A, Al-Mesfer S, Mullaney PB, Wheeler DT. Effectiveness and complications of mitomycin C use during pediatric glaucoma surgery Ophthalmology. 1998;105:1915–20
18. Biedner BZ, Rothkoff L. Combined trabeculotomy-trabeculectomy
compared with primary trabeculotomy for congenital glaucoma J Pediatr Ophthalmol and Strabismus. 1998;35:49–50
19. Dateline TS, Jacobi PC, Krieglstein GK. Prognosis of primary ab externo surgery for primary congenital glaucoma Br J Ophthalmol. 1999;83:317–22
20. Haas J. Principles and problems of therapy in congenital glaucoma Invest Ophthalmol. 1968;7:140–46
21. Good WV, Hing S, Irvine AR, Hoyt CS, Taylor DSI. Postoperative endophthalmitis in children following cataract surgery J Pediatr Ophthalmol Strabismus. 1990;27:283–85
22. Guo S, Nelson LB, Calhoun J, Levin A. Simultaneous surgery for bilateral congenital cataracts J Pediatr Ophthalmol Strabismus. 1990;27:23–25
23. Kushner BJ. Simultaneous surgery for bilateral congenital cataracts (discussion) J Pediatr Ophthalmol Strabismus. 1990;27:26–27
24. Yagasaki T, Sato M, Awaya S, Nakamura. Changes in nystagmus after simultaneous surgery for bilateral cataracts Jpn J Ophthalmol. 1993;37:330–38
25. Zwaan J. Simultaneous surgery for bilateral pediatric cataracts Ophthalmic Surg Lasers. 1996;27:15–20
26. Masket S. Consultation section. Cataract surgical problem J Cataract Refract Surg. 1997;23:1427–42
27. Duthie OM. Bilateral cataract extraction Trans Ophthalmol Soc UK. 1955;75:25–31
28. Jardine P. Simultaneous bilateral cataract extraction Trans Ophthalmol Soc UK. 1970;70:719–24
29. Joseph N, David R. Bilateral cataract in one session :report on five years experience Br J Ophthalmol. 1977;61:619–21
30. Fenton PJ, Gardner ID. Simultaneous bilateral intraocular surgery Trans Ophthalmol Soc UK. 1982;102:298–301
31. Shepard DD. iConsultation Section. Are there any indications for simultaneous bilateral cataract-intraocular lens (IOL) surgery? J Cataract Refract Surg. 1988;14:339–45
32. Akingbehin T, Sunderraj P. Simultaneous bilateral lens implantation:Is the procedure justified ? Eur J Implant Refract Surg. 1992;3:131–33
33. Hartitt R, Moriarty A, Mastellone G. Is simultaneous bilateral cataract extraction with lens implantation justified ? Eur J Implant Refract Surg. 1992;3:134–37
34. Adhikary HP, Harrington I. Simultaneous bilateral intraocular lens implantation Eur J Implant Refract Surg. 1992;3:138–89
35. Nielson PJ. Simultaneous bilateral cataract extraction :ECCE versus ICCE Eur J Implant Refract Surg. 1992;3:140–44
36. Mission GP, Pearce JL, Fielder AR. Bilateral cataract surgery (Letter) Lancet. 1992;339:623
37. Beatty S, Aggarwal RK, David DB, Guarro M, Jones H, Pearce JL. Simultaneous bilateral cataract extraction in the UK Br J Ophthalmol. 1995;79:1111–14
38. Arshinoff S. Simultaneous bilateral cataract surgery (Letter) Cataract Refract Surg. 1998;24:1015–16
39. Keskinbora HK. Simultaneous bilateral cataract surgery (Letter) J Cataract Refract Surg. 1999;25:304
40. Ramsay AL, Diaper CJM, Saba SN, Beirouty ZAY, Fawzi HH. Simultaneous bilateral cataract extraction J Cataract Refract Surg. 1999;25:753–62
41. BenEzra D, Chirambo MC. Bilateral versus unilateral cataract extraction:advantages and complications Br J Ophthalmol. 1978;62:770–73
42. Hugkulstone CE, Stevenson L, Vernon SA. Simultaneous bilateral trabeculectomy Eye. 1994;8:398–401
43. Watanabe H, Sata S, Maeda N, Inoue Y, Shimomura Y, Tano Y. Bilateral corneal infection as a complication of laser in Situ Keratomileusis Arch Ophthalmol. 1997;115:1593–94
44. Mulhern MG, Condon PI, O'Keefe M. Endophthalmitis after astigmatic myopic laser in situ keratomileusis J Cataract Refract Surg. 1997;23:948–50
45. Quiros PA, Chuck RS, Smith RE, Irvien JA, McDonnell PJ, Chao LC. Infectious Ulcerative keratitis after laser in situ keratomileusis Arch Ophthalmol. 1999;117:1423–27
46. Waring GO III, Carr JD, Stulting RD, Thompson KP, Wiley W. Prospective randomised comparison of simultaneous and sequential bilateral laser in situ keratomileusis for the correction of myopia Ophthalmology. 1999;106:732–38
47. Gimbel HV, van Westenbrugg JA, Penno EEA, Ferensowicz M, Feinerman GA, Chen R. Simultaneous bilateral laser in situ keratomileusis Ophthalmology. 1999;106:1461–68
48. Romano PE, Robinson JA. General anesthesia morbidity and mortality in eye surgery at a children's hospital J Pediatr Ophthalmol and Strabismus. 1981;18:17–21
49. Tiret L, Nivoche Y, Hatton F, Desmonts JM, Vourc'h G. Complications related to anaesthesia in infants and children : a prospective surgery of 40240 anesthetics Br J Anaesth. 1988;61:263–69
50. Laycock GJ, McNicol LR. Hypoxaemia during recovery from anaesthesia: An audit of children after general anaesthesia for routine elective surgery Anesthesiology. 1988;43:985–87
51. Cohen MM, Cameron CB. Should you cancel the operation when a child has an upper respiratory tract infection? Anesth Analg. 1991;72:282–88
52. Keeman RI, Boyan CP. Cardiac arrest during anesthesia: A study of incidence and causes JAMA. 1985;253:2373–77
53. Saint Maurice C. Paediatric anaesthesia Curr Opin Anaesth. 1994;7:249–50