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Case series of 12 children with progressive axial myopia following unilateral cataract extraction
Case Series of 12 Children With Progressive Axial Myopia Following Unilateral Cataract Extraction M. Vanathi, MD, Radhika Tandon, MD, FRCOphth, FRCS, Jeewan S. Titiyal, MD, and Rasik B. Vajpayee, MBBS, MS Purpose: We report the occurrence of unilateral progressive axial myopia ipsilaterally in a retrospective analysis of 12 children following uniocular cataract surgery. Methods: A retrospective analysis of the case records of children who had developed progressive ipsilateral axial myopia following unilateral cataract surgery was done. Follow-up ranged from 4 years to 14 years. Results: Twelve children, 7 male and 5 female, were eligible for the study. Mean age at the time of cataract surgery was 6.7 ⫾ 2.5 years (range, 4-11 years) and follow-up period was 7.8 ⫾ 3.1 years (range, 4-14 years). Ten children (83.3%) had traumatic cataracts of which 8 had undergone repair of penetrating eye injuries and 2 had suffered blunt trauma. Two patients (16.7%) had been operated for unilateral developmental cataracts. Three children had aphakia and nine had pseudophakia. Degree of myopic shift ranged from ⫺4.75 D to ⫺15 D (mean, ⫺7.35 ⫾ 3.51 D). Axial length difference between the 2 eyes ranged from 1 mm to 3.5 mm (mean, 2.2 ⫾ 0.9 mm). Mean increase of axial length from preoperative recording to final follow-up was 2.53 ⫾ 0.90 mm (range, 1.6-4 mm). Three children had to undergo IOL explantation and 1 had posterior chamber intraocular lens exchange due to high unilateral myopia. The rest were visually rehabilitated with either spectacles or contact lenses. Conclusion: Following cataract surgery pediatric eyes may suffer from progressive axial myopia. Trauma or multiple ocular surgeries may be predisposing factors. (J AAPOS 2002;6: 228-32)
ptimal management to achieve good visual outcome in unilateral pediatric cataracts still remains controversial. Early surgery, contact lens correction of aphakia, and vigorous amblyopia therapy help in achieving a better visual outcome.1-5 Though intraocular lens (IOL) implantation offers good optical rehabilitation, the long-term safety of IOLs has yet to be convincingly established.6-12 A trend of increase in ocular axial length and myopic shift in refraction has been observed to occur following pediatric cataract extraction.11,13,14 We wish to report our observations of this phenomenon in 12 children with unilateral cataract who demonstrated progressive unilateral axial myopia in the operated eye.
O
From the Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India. Presented in part at the Annual Symposium of Cataract and Refractive Surgery of the American Society of Cataract and Refractive Surgery Conference, Boston, Massachusetts, May 20-24, 2000 Submitted June 19, 2001. Revision accepted February 1, 2002. Reprint requests: Radhika Tandon, MD, FRCOphth, FRCS, Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi 110029. Copyright © 2002 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/2002/$35.00 ⫹ 0 75/1/123658 doi:10.1067/mpa.2002.123658
228
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PATIENTS AND METHODS A retrospective evaluation of the available records of 12 children who had undergone unilateral cataract surgery and subsequently developed progressive axial myopia was done. Nine cases were operated at our center and 3 cases had been operated outside the center and reported to our lens clinic with poor vision. Over the same period (12 years), a total of 4872 pediatric cataract surgeries had been performed and a total of 2029 children were seen in the lens clinic at our hospital. Most of our patients are from distant places and were not available for follow-up. The etiology of cataract, age at surgery, details of surgical procedure, best corrected visual acuity, refractive correction including near addition, degree of myopia, intraocular pressure, posterior segment status, change in ocular axial length, and change in refractive status of the children available for study was noted from the hospital records and referral notes available with the patients. The clinical data are summarized in Table 1. Cataract extraction was achieved by either lensectomy or lens aspiration with or without IOL implantation. Other surgical procedures that had been performed included previous corneal perforation repair (8), intraocular implant exchange (1) or removal (2), secondary IOL implantation (2), surgical membranectomy Journal of AAPOS
Journal of AAPOS Volume 6 Number 4 August 2002
(2), YAG laser capsulotomy (4), and penetrating keratoplasty (1). IOL power calculations had been based on the preoperative ocular biometry measurements and prescribed for emmetropia. The initial postoperative refraction recorded at 6 weeks following surgery was taken as the baseline and the postoperative refraction at the last follow-up was recorded and used to calculate the amount of myopic shift. The overall myopic shift divided by the number of years of follow-up for each child was used to estimate the approximate rate of myopic shift per year. The preoperative axial length was used as a baseline to determine the change in axial length. The possibility of glaucoma was excluded by intraocular pressure measurement and disc evaluation during follow-ups. Follow-up records were available for a period ranging from 4 years to 14 years. Final management in terms of optical rehabilitation included contact lenses, IOL removal, spectacles, near vision correction prescribed as reading glasses or bifocals, and penetrating keratoplasty.
RESULTS Twelve children (7 male, 5 female) were eligible for the study. Mean age at the time of cataract surgery was 6.7 ⫾ 2.5 years (range, 4-11 years). Ten children (83.3%) had unilateral traumatic cataracts of which 8 had undergone primary repair of penetrating eye injuries and 2 had sustained blunt trauma. Of the latter 2 children, 1 (case 2, Table 1) underwent pars plana lensectomy and a secondary posterior chamber IOL implant 3 months later, and posterior chamber IOL exchange 4 years later, while the other (case 8, Table 1) had undergone lens aspiration followed by YAG laser capsulotomy. Two children (16.7%) had been operated on for unilateral developmental cataracts. Three children had aphakia and 9 had pseudophakia, of which 6 had primary posterior chamber IOL implants, 1 had a primary iris claw anterior chamber lens, and 2 had secondary posterior chamber lens implants. Two children had undergone IOL removal due to progressively increasing high unilateral myopia (case 9) and pseudophakic bullous keratopathy (case 11). In final management for optical rehabilitation, 1 more child had IOL removal (case 6) and one was advised IOL removal (case 7), but the parents were unwilling. Four patients had YAG capsulotomy for after-cataract. All patients (100%) had undergone more than 1 surgical procedure on the affected eye. The mean follow-up was 7.8 ⫾ 3.1 years (Table 1). The increase in axial length in the involved eye ranged from 1.6 to 4.0 mm (mean, 2.5 ⫾ 0.9 mm). The difference in axial length between the 2 eyes ranged from 1.0 to 3.5 mm (mean, 2.2 D ⫾ 0.9 mm). Degree of myopic shift (dioptric change in refractive error) ranged from ⫺4.75 D to ⫺15.00 D (mean, ⫺7.35 ⫾ ⫹3.51 D). Refraction at last follow-up ranged from ⫹7.50 D to ⫺15.00 D. The average myopic shift in children who were 4 years old at time
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of cataract surgery was 7.92 ⫾ 2.67 D over the follow-up period (mean estimated rate, 1.38 ⫾ 0.31 D/yr) and in children 5 to 11 years of age was 7.20 ⫾ 4.36 D (mean, 0.96 ⫾ 0.64 D/yr; P ⫽ .70). Mean axial length growth in cases 4 years old was 2.32 ⫾ 0.89 mm and in cases 5 to 11 years old was 2.66 ⫾ 0.96 mm (P ⫽ .73). The fellow eye of all 12 patients was emmetropic. Anisometropia was optically corrected with contact lenses or glasses in 9 children. Near vision correction had been prescribed as reading glasses or bifocals for all children. Patching therapy had been given for amblyopia as and when necessary. No patient had elevated intraocular pressure, but there was a mean intraocular pressure difference of 0.58 ⫾ 0.51 mm Hg between the 2 eyes. The posterior segment status was normal in all cases.
DISCUSSION Gordon and Donzis,15 in their study of the normal refractive development of the human eye, have found that the axial length progressively increases after birth and is within ⫾ 1.0 mm of adult length by 5 to 6 years of age. A rapid postnatal growth phase of 3.7 to 3.8 mm in the first year of life, a slower infantile phase of increase of 1.1 to 1.2 mm up to 5 years of age, followed by a slow juvenile phase of increase of 1.3 to 1.4 mm up to 13 years of age has been described.16 The phenomenon of myopic shift in children operated for cataract before 2 years of age has been observed in few studies.11,14,17 This myopic shift has been observed to lessen with increasing age.8,14,17 However, the reverse has also been seen. A retrospective study of children with aphakia by McClatchy and Parks18 revealed a smaller rate of myopic shift in very young children compared to older children and also in bilateral cataract as compared to unilateral cataract although the differences were not statistically significant. Our series shows a progressive myopic shift in refraction with documented ipsilateral axial elongation in 9 cases of unilateral pseudophakia and 3 cases of unilateral aphakia. The age at which surgery was performed ranged from 4 to 11 years and follow-up ranged from 4 to 14 years. Although the number is small, the duration of observation is longer than most studies. Axial length changes in pediatric pseudophakia have also been noted to be greater following traumatic cataract than congenital or developmental cataract.19 In our study, too, although the numbers are very small, eyes with traumatic cataracts (n ⫽ 7) and developmental cataract (n ⫽ 2) with multiple eye surgeries experienced ipsilateral axial elongation of eyes over a period of several years. A severe visual deprivation in childhood has been postulated to induce an axial globe elongation and myopia.13,20 Considering the age at surgery of our patients, the increase in axial length and the amount of myopic shift was higher compared to that reported in similar age groups in
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Table 1 . Summary of clinical details Age at Age at cataract onset of surgery cataract (years) No Etiology (years)
Refractive error (D)
Details of cataract surgery
FU
Additional surgery
Initial
Final
Lens asp & PC IOL Pars plana lensectomy Lens asp & PC IOL Lens asp & PC IOL Lens asp (no IOL) Lens asp & PC IOL
4 7 5 6 7 11
Repair of corneal perforation Secondary PC IOL ⫹ IOL exchange Repair of corneal perforation Membranectomy Repair of corneal perforation Repair of corneal perforation & YAG capsulotomy YAG capsulotomy
⫺0.5 0 0 0 NA 0
⫺7.0 ⫺4.75 ⫺5.0 ⫺8.5 2 ⫺15.0
YAG capsulotomy Repair of corneal perforation, IOL removal 7 yrs later Repair of corneal perforation, virectomy, YAG capsulotomy Repair of corneal perforation, PK, IOL removal & membranectomy Repair of corneal perforation, secondary PC IOL
10.8 NA
4.0 NA
11.5
7.5
1 2 3 4 5 6
T T T D T T
4.5 5 4 4 10 7
4.5 5 4 4 10 7
7
D
4
4
Lens asp & iris claw IOL
8 9
T T
7 7
7 7
Lens asp Lens asp & PC IOL
14 7
10
T
11
11
Lensectomy
12
11
T
9
9
Lens asp & PC IOL
9
12
T
8
8
Lens asp
5
Mean ⫾ SD
7
7.8 ⫾ 3.1
0.25
⫺2 ⫺4.3
⫺10.0
⫺5.5 ⫺13.5
Dioptric change ref error— difference in diopters between final and initial refractive error. #, reading glasses; ##, bifocals. D, Developmental cataract; FU, follow-up in years; IOP, intraocular pressure; lens asp, lens aspiration; PC IOL, posterior chamber intraocular lens; PK, penetrating keratoplasty; T, trauma.
other studies (Table 2) 8,14,19 and similar to that reported by Kora et al.21 Contradictory reports of the effect of cataract surgery on axial growth in infant eyes are also worth noting.22 No significant retardation or acceleration of axial growth was found in eyes implanted with IOLs compared with normal eyes in the series of pediatric pseudophakia evaluated by Flitcroft et al.23 Ocular axial length measured in unilateral congenital cataract has also been found to be less than normal eyes.24 Early surgery and visual rehabilitation with IOL implantation has been reported to slow down axial elongation.25 Our study reveals progressive axial elongations of the globe following unilateral cataract extraction compared with that of the normal eye. The amount of change also
seems slightly higher than other studies (Table 2). Multiple intraocular surgical procedures were done in all 12 cases of our study. The progressive refractive myopic shift and axial elongation may perhaps be related to the multiple surgeries leading to changes in ocular rigidity. Form vision deprivation and amblyopia may also have been contributory to the progressive axial myopia. Ocular trauma should also be considered as one of the contributory factors, and a possible mechanism could be a change in scleral rigidity and/or an elevation of intraocular pressure, which was undoubtedly slight and out of range for diagnosing confirmed glaucoma. Our series highlights that there may be a progressive axial myopia following unilateral cataract extraction with
Table 2 . Comparative evaluation of data with previous studies Author
Year
Dahan and Drusedau8
1997
Enyedi et al14
1998
Sorkin and Lambert19 Present study
1997 2000
Age at surgery (years) Less than 1.5 1.5-3 3-8 0-2 2-6 6-8 Greater than 8 3-9 4-11
Mean follow-up in years (range)
Mean axial length increase (mm)
—
3.59 ⫾ 1.8 0.75 ⫾ 0.85 0.76 ⫾ 0.69 N/A
2.5 3.5 3 1.8 (0.5-6.6) 3.1 8.3 (4-14)
0.64 2.53 ⫾ 0.9
Mean myopic shift 6.39 ⫾ 3.68 D 2.73 ⫾ 1.4 D 2.6 ⫾ 1.84 D ⫺3.0 D ⫺1.5 D ⫺1.8 D ⫺0.38 D ⫺1.01 D ⫺7.35 ⫾ 3.51 D
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Final
Change in axial length (mm)
Axial length difference between 2 eyes (mm)
IOP in affected eye (fellow eye) mm Hg
21.3 22.8 22.8 23.8 24.7 23.6
23.52 24.4 24.6 24.26 27.69 27.58
2.26 1.6 1.8 1.62 3 4
1.7 1 NA 1.16 3.39 3.5
14 (14) 14 (14) 17 (16) 15.6 (14.6) 17 (16) 16 (15)
⫺10.25
21.8
25.4
3.6
3
14 (14)
⫺6.75 —
22.8 22.5
26.6 24.53
3.8 2
3.2 1.8
⫺4
22.4
24.33
1.9
⫺3.5
23.1
25.4
⫺9.25
—
24.3
Axial length (mm)
Dioptric change ref error
Initial
⫺6.5 ⫺4.75 ⫺5 ⫺8.5 — ⫺15
⫺7.35 ⫾ 3.51
Final optical rehabilitation
231
Final visual acuity 6/12 6/18 6/18 6/36 6/18 6/12
14 (14) 17 (16)
Contact lens & # Spectacles ## Contact lens & # Contact lens & # Contact lens & # IOL removal & spectacles## Spectacles #, IOL removal advised Contact lens # PK advised
1.53
18 (18)
Contact lens & #
6/12
2.3
2.2
19 (18)
Contact lens & #
6/36
—
1.8
15.6 (14.6)
Contact lens & #
6/24
2.53 ⫾ 0.9
2.2 ⫾ 0.91
0.58 ⫾ 0.51
or without IOL implantation in some children. The pathogenesis of increased axial growth following unilateral cataract extraction is not clearly understood. The phenomenon of globe elongation has been attributed to be influenced by refractive blurs26-30 in developing eyes, intraocular pressure variations,31,32 and scleral changes.33,34 All patients with good visual acuity in our series had been given appropriate near vision correction for near and distance at all follow-ups. Hence the influences of refractive blur being responsible for the axial elongation of the globe, in our series, can be excluded. Our patients had a mean intraocular pressure difference of 0.58 ⫾ 0.51 mm Hg between the 2 eyes. Intraocular pressure changes below threshold values for glaucoma can influence ocular length in growing eyes.31,32 Subtle intraocular changes as a cause for progressive globe elongation remains to be considered. Further prospective studies with a larger case series are recommended to evaluate this possibility. Our series, being small and a retrospective analysis, has its limitations that no definite conclusion can be drawn regarding the possible mechanisms for this phenomenon of progressive ipsilateral axial elongation of the globe and no conclusions can be derived regarding the incidence of this progressive myopic phenomenon. Multiple factors including age at surgery, ocular trauma, laterality (unilateral cases), duration and severity of form vision deprivation, amblyopia, IOL implantation, multiple ocular surgeries, intraocular pressure changes, and altered scleral rigidity perhaps play a significant role in this phenomenon.
1/60 6/24 —
References 1. Beller R, Hoyt CS, Marg E, Odom JV. Good visual function after neonatal surgery for congenital monocular cataracts. Am J Ophthalmol 1981;91:559-65. 2. Greg FM, Parks MM. Stereopsis after congenital monocular cataract extractions. Am J Ophthalmol 1992;114:314-7. 3. Birch EE, Swanson WH, Stager DR, Woody M, Everett M. Outcome after very early treatment of dense congenital unilateral cataract. Invest Ophthalmol Vis Sci 1993;34:3687-99. 4. Birch EE, Stager DR. The critical period for surgical treatment of dense congenital unilateral cataract. Invest Ophthalmol Vis Sci 1996; 37:1532-8. 5. Brown SM, Archer S, Del Monte MA. Stereopsis and binocular vision after cataract surgery for unilateral infantile cataract. JAAPOS 1999;3:1-5. 6. Sinskey RM, Amin PA, Lingna R. Cataract extraction and intraocular lens implantation in an infant with a monocular congenital cataract. J Cataract Refract Surg 1994;20:647-51. 7. Ben Ezra D. Cataract surgery and intraocular lens implantation in children. Am J Ophthalmol 1996;121:224-5. 8. Dahan E, Drusedau MU. Choice of lens and dioptric power in paediatric pseudophakia. J Cataract Refract Surg 1997;23(suppl 1): 618-23. 9. Spierer A, Desatrik H, Blumenthal M. Refractive status in children after long-term follow-up of cataract surgery with intraocular lens implantation. J Pediatr Ophthalmol Strabismus 1999;36:25-9. 10. Awner S, Buckley EG, De Varo JM, Seaber JH. Unilateral pseudophakia in children under 4 years. J Pediatr Ophthalmol Strabismus 1996;33:230-6. 11. Lambert SR, Buckley EG, Plager DA, Medow NB, Wilson ME. Unilateral intraocular lens implantations during the first 6 months of life. JAAPOS 1999;3:344-9. 12. Knight-Nanan D, O’Keefe M, Bowell R. Outcome and complications of intraocular lenses in children with cataract. J Cataract Refract Surg 1996;22:730-6.
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13. Zhang Z, Li S. The visual deprivation and increase in axial length in patients with cataracts. Yen Ko Hsuch Pao 1996;12:135-7. 14. Enyedi LB, Peterseim MW, Freedman SF, Buckley EG. Refractive changes after pediatric intraocular lens implantation. Am J Ophthalmol 1998;126:772-81. 15. Gordon RA, Donzis PB. Refractive development of the human eye. Arch Ophthalmol 1985;103:785-9. 16. Larsen JS. The sagittal growth of the eye. Ultrasonic measurement of the axial length of the eye from birth to puberty. Acta Ophthalmologica 1971;49:873-86. 17. Leseur L, Arne JL, Chapotat E. Predictability of intraocular lens power calculation in the treatment of cataracts in children. J Fr Ophthalmol 1999;22:209-12. 18. McClatchy SK, Parks MM. Myopic shift after cataract removal in childhood. J Pediatr Ophthalmol Strabismus 1997;34:88-95. 19. Sorkin JA, Lambert SR. Longitudinal changes in axial length in pseudophakic children. J Cataract Refract Surg 1997;23:624-8. 20. Calossi A. Increase in axial length in infantile traumatic cataract. Optom Vis Sci 1994;71:386-91. 21. Kora Y, Shimuzu K, Inatomi M, Fukado Y, Ozawa T. Eye growth after cataract extraction and intraocular lens implantation in children. Ophthalmic Surg 1993;24:467-75. 22. Hutchinson AK, Wilson ME, Saunders RA. Outcomes and ocular growth rates after intraocular lens implantation in the first 2 years of life. J Cataract Refract Surg 1998;24:846-52. 23. Flitcroft DI, Knight-Nanan D, Bowell R, Lanigan B, O’Keefe M. Intraocular lenses in children: changes in axial length, corneal curvature and refraction. Br J Ophthalmol 1999;83:265-9. 24. Kugelberg U, Zetterstrom C, Syren Nordquist S. Ocular axial length
25.
26. 27. 28. 29.
30. 31.
32.
33. 34.
in children with unilateral congenital cataract. Acta Ophthalmol Scand 1996;74:220-3. Griener ED, Dhan E, Lambert SR. Effect of age at the time of cataract surgery on subsequent axial growth in infant eyes. J Cataract Refract Surg 1999;25:1209-13. Schaeffel F, Howland HC. Mathematical model of emmetropization in the chicken. J Opt Soc Am A 1988;5:2080-6. Schaeffel F, Glasser A, Howland HC. Accomodation, refractive error and eye growth in chickens. Vis Res 1988;28:639-57. Irving EL, Callender MG, Sivak JG. Inducing myopia, hyperopia and astigmatism in chicks. Optom Vis Sci 1991;68:364-368. Wildsoet C, Wallmann J. Choroidal and scleral mechanisms for compensation for spectacle lenses in children. Vis Res 1995;35:117594. Medine A. A model for emmetropization predicting the progression of ametropia. Ophthalmologica 1987;194:133-9. Papastergiou GI, Schmid GF, Riva CE, Mendel MJ, Stone RA, Laties AM. Ocular axial length and choroidal thickness in newly hatched chicks and one-year-old chickens fluctuate in a diurnal pattern that is influenced by visual experience and intraocular pressure. Exp Eye Res 1998;66:195-205. Nickla DL, Wildsoet C, Wallman J. The circadian rhythm in intraocular pressure and its relation to diurnal ocular growth changes in chicks. Exp Eye Res 1998;66:183-93. Phillips JR, McBrien NA. Form deprivation myopia: elastic properties of the sclera. Ophthalmic Physiol Opt 1995;15:357-62. Wallmann J. Retinal influences on sclera underlie visual deprivation amblyopia. Ciba Found Symp 1990;155:126-34; discussion 135-41.
An Eye on the Arts – The Arts on the Eye
But for those first affections, Those shadowy recollections, Which, be they what they may, Are yet the fountain-light of all our day, Are yet a master-light of all our seeing; Uphold us, cherish, and have power to make Our noisy years seem moments in the being Of the Eternal Silence: truths that wake, To perish never: Which neither listlessness, nor mad endeavor, Nor man nor boy, Nor all that is at enmity with joy, Can utterly abolish or destroy! —William Wordsworth (from “Ode: Intimations of Immortality”)
ptimal management to achieve good visual outcome in unilateral pediatric cataracts still remains controversial. Early surgery, contact lens correction of aphakia, and vigorous amblyopia therapy help in achieving a better visual outcome.1-5 Though intraocular lens (IOL) implantation offers good optical rehabilitation, the long-term safety of IOLs has yet to be convincingly established.6-12 A trend of increase in ocular axial length and myopic shift in refraction has been observed to occur following pediatric cataract extraction.11,13,14 We wish to report our observations of this phenomenon in 12 children with unilateral cataract who demonstrated progressive unilateral axial myopia in the operated eye.
O
From the Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India. Presented in part at the Annual Symposium of Cataract and Refractive Surgery of the American Society of Cataract and Refractive Surgery Conference, Boston, Massachusetts, May 20-24, 2000 Submitted June 19, 2001. Revision accepted February 1, 2002. Reprint requests: Radhika Tandon, MD, FRCOphth, FRCS, Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi 110029. Copyright © 2002 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/2002/$35.00 ⫹ 0 75/1/123658 doi:10.1067/mpa.2002.123658
228
August 2002
PATIENTS AND METHODS A retrospective evaluation of the available records of 12 children who had undergone unilateral cataract surgery and subsequently developed progressive axial myopia was done. Nine cases were operated at our center and 3 cases had been operated outside the center and reported to our lens clinic with poor vision. Over the same period (12 years), a total of 4872 pediatric cataract surgeries had been performed and a total of 2029 children were seen in the lens clinic at our hospital. Most of our patients are from distant places and were not available for follow-up. The etiology of cataract, age at surgery, details of surgical procedure, best corrected visual acuity, refractive correction including near addition, degree of myopia, intraocular pressure, posterior segment status, change in ocular axial length, and change in refractive status of the children available for study was noted from the hospital records and referral notes available with the patients. The clinical data are summarized in Table 1. Cataract extraction was achieved by either lensectomy or lens aspiration with or without IOL implantation. Other surgical procedures that had been performed included previous corneal perforation repair (8), intraocular implant exchange (1) or removal (2), secondary IOL implantation (2), surgical membranectomy Journal of AAPOS
Journal of AAPOS Volume 6 Number 4 August 2002
(2), YAG laser capsulotomy (4), and penetrating keratoplasty (1). IOL power calculations had been based on the preoperative ocular biometry measurements and prescribed for emmetropia. The initial postoperative refraction recorded at 6 weeks following surgery was taken as the baseline and the postoperative refraction at the last follow-up was recorded and used to calculate the amount of myopic shift. The overall myopic shift divided by the number of years of follow-up for each child was used to estimate the approximate rate of myopic shift per year. The preoperative axial length was used as a baseline to determine the change in axial length. The possibility of glaucoma was excluded by intraocular pressure measurement and disc evaluation during follow-ups. Follow-up records were available for a period ranging from 4 years to 14 years. Final management in terms of optical rehabilitation included contact lenses, IOL removal, spectacles, near vision correction prescribed as reading glasses or bifocals, and penetrating keratoplasty.
RESULTS Twelve children (7 male, 5 female) were eligible for the study. Mean age at the time of cataract surgery was 6.7 ⫾ 2.5 years (range, 4-11 years). Ten children (83.3%) had unilateral traumatic cataracts of which 8 had undergone primary repair of penetrating eye injuries and 2 had sustained blunt trauma. Of the latter 2 children, 1 (case 2, Table 1) underwent pars plana lensectomy and a secondary posterior chamber IOL implant 3 months later, and posterior chamber IOL exchange 4 years later, while the other (case 8, Table 1) had undergone lens aspiration followed by YAG laser capsulotomy. Two children (16.7%) had been operated on for unilateral developmental cataracts. Three children had aphakia and 9 had pseudophakia, of which 6 had primary posterior chamber IOL implants, 1 had a primary iris claw anterior chamber lens, and 2 had secondary posterior chamber lens implants. Two children had undergone IOL removal due to progressively increasing high unilateral myopia (case 9) and pseudophakic bullous keratopathy (case 11). In final management for optical rehabilitation, 1 more child had IOL removal (case 6) and one was advised IOL removal (case 7), but the parents were unwilling. Four patients had YAG capsulotomy for after-cataract. All patients (100%) had undergone more than 1 surgical procedure on the affected eye. The mean follow-up was 7.8 ⫾ 3.1 years (Table 1). The increase in axial length in the involved eye ranged from 1.6 to 4.0 mm (mean, 2.5 ⫾ 0.9 mm). The difference in axial length between the 2 eyes ranged from 1.0 to 3.5 mm (mean, 2.2 D ⫾ 0.9 mm). Degree of myopic shift (dioptric change in refractive error) ranged from ⫺4.75 D to ⫺15.00 D (mean, ⫺7.35 ⫾ ⫹3.51 D). Refraction at last follow-up ranged from ⫹7.50 D to ⫺15.00 D. The average myopic shift in children who were 4 years old at time
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of cataract surgery was 7.92 ⫾ 2.67 D over the follow-up period (mean estimated rate, 1.38 ⫾ 0.31 D/yr) and in children 5 to 11 years of age was 7.20 ⫾ 4.36 D (mean, 0.96 ⫾ 0.64 D/yr; P ⫽ .70). Mean axial length growth in cases 4 years old was 2.32 ⫾ 0.89 mm and in cases 5 to 11 years old was 2.66 ⫾ 0.96 mm (P ⫽ .73). The fellow eye of all 12 patients was emmetropic. Anisometropia was optically corrected with contact lenses or glasses in 9 children. Near vision correction had been prescribed as reading glasses or bifocals for all children. Patching therapy had been given for amblyopia as and when necessary. No patient had elevated intraocular pressure, but there was a mean intraocular pressure difference of 0.58 ⫾ 0.51 mm Hg between the 2 eyes. The posterior segment status was normal in all cases.
DISCUSSION Gordon and Donzis,15 in their study of the normal refractive development of the human eye, have found that the axial length progressively increases after birth and is within ⫾ 1.0 mm of adult length by 5 to 6 years of age. A rapid postnatal growth phase of 3.7 to 3.8 mm in the first year of life, a slower infantile phase of increase of 1.1 to 1.2 mm up to 5 years of age, followed by a slow juvenile phase of increase of 1.3 to 1.4 mm up to 13 years of age has been described.16 The phenomenon of myopic shift in children operated for cataract before 2 years of age has been observed in few studies.11,14,17 This myopic shift has been observed to lessen with increasing age.8,14,17 However, the reverse has also been seen. A retrospective study of children with aphakia by McClatchy and Parks18 revealed a smaller rate of myopic shift in very young children compared to older children and also in bilateral cataract as compared to unilateral cataract although the differences were not statistically significant. Our series shows a progressive myopic shift in refraction with documented ipsilateral axial elongation in 9 cases of unilateral pseudophakia and 3 cases of unilateral aphakia. The age at which surgery was performed ranged from 4 to 11 years and follow-up ranged from 4 to 14 years. Although the number is small, the duration of observation is longer than most studies. Axial length changes in pediatric pseudophakia have also been noted to be greater following traumatic cataract than congenital or developmental cataract.19 In our study, too, although the numbers are very small, eyes with traumatic cataracts (n ⫽ 7) and developmental cataract (n ⫽ 2) with multiple eye surgeries experienced ipsilateral axial elongation of eyes over a period of several years. A severe visual deprivation in childhood has been postulated to induce an axial globe elongation and myopia.13,20 Considering the age at surgery of our patients, the increase in axial length and the amount of myopic shift was higher compared to that reported in similar age groups in
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Table 1 . Summary of clinical details Age at Age at cataract onset of surgery cataract (years) No Etiology (years)
Refractive error (D)
Details of cataract surgery
FU
Additional surgery
Initial
Final
Lens asp & PC IOL Pars plana lensectomy Lens asp & PC IOL Lens asp & PC IOL Lens asp (no IOL) Lens asp & PC IOL
4 7 5 6 7 11
Repair of corneal perforation Secondary PC IOL ⫹ IOL exchange Repair of corneal perforation Membranectomy Repair of corneal perforation Repair of corneal perforation & YAG capsulotomy YAG capsulotomy
⫺0.5 0 0 0 NA 0
⫺7.0 ⫺4.75 ⫺5.0 ⫺8.5 2 ⫺15.0
YAG capsulotomy Repair of corneal perforation, IOL removal 7 yrs later Repair of corneal perforation, virectomy, YAG capsulotomy Repair of corneal perforation, PK, IOL removal & membranectomy Repair of corneal perforation, secondary PC IOL
10.8 NA
4.0 NA
11.5
7.5
1 2 3 4 5 6
T T T D T T
4.5 5 4 4 10 7
4.5 5 4 4 10 7
7
D
4
4
Lens asp & iris claw IOL
8 9
T T
7 7
7 7
Lens asp Lens asp & PC IOL
14 7
10
T
11
11
Lensectomy
12
11
T
9
9
Lens asp & PC IOL
9
12
T
8
8
Lens asp
5
Mean ⫾ SD
7
7.8 ⫾ 3.1
0.25
⫺2 ⫺4.3
⫺10.0
⫺5.5 ⫺13.5
Dioptric change ref error— difference in diopters between final and initial refractive error. #, reading glasses; ##, bifocals. D, Developmental cataract; FU, follow-up in years; IOP, intraocular pressure; lens asp, lens aspiration; PC IOL, posterior chamber intraocular lens; PK, penetrating keratoplasty; T, trauma.
other studies (Table 2) 8,14,19 and similar to that reported by Kora et al.21 Contradictory reports of the effect of cataract surgery on axial growth in infant eyes are also worth noting.22 No significant retardation or acceleration of axial growth was found in eyes implanted with IOLs compared with normal eyes in the series of pediatric pseudophakia evaluated by Flitcroft et al.23 Ocular axial length measured in unilateral congenital cataract has also been found to be less than normal eyes.24 Early surgery and visual rehabilitation with IOL implantation has been reported to slow down axial elongation.25 Our study reveals progressive axial elongations of the globe following unilateral cataract extraction compared with that of the normal eye. The amount of change also
seems slightly higher than other studies (Table 2). Multiple intraocular surgical procedures were done in all 12 cases of our study. The progressive refractive myopic shift and axial elongation may perhaps be related to the multiple surgeries leading to changes in ocular rigidity. Form vision deprivation and amblyopia may also have been contributory to the progressive axial myopia. Ocular trauma should also be considered as one of the contributory factors, and a possible mechanism could be a change in scleral rigidity and/or an elevation of intraocular pressure, which was undoubtedly slight and out of range for diagnosing confirmed glaucoma. Our series highlights that there may be a progressive axial myopia following unilateral cataract extraction with
Table 2 . Comparative evaluation of data with previous studies Author
Year
Dahan and Drusedau8
1997
Enyedi et al14
1998
Sorkin and Lambert19 Present study
1997 2000
Age at surgery (years) Less than 1.5 1.5-3 3-8 0-2 2-6 6-8 Greater than 8 3-9 4-11
Mean follow-up in years (range)
Mean axial length increase (mm)
—
3.59 ⫾ 1.8 0.75 ⫾ 0.85 0.76 ⫾ 0.69 N/A
2.5 3.5 3 1.8 (0.5-6.6) 3.1 8.3 (4-14)
0.64 2.53 ⫾ 0.9
Mean myopic shift 6.39 ⫾ 3.68 D 2.73 ⫾ 1.4 D 2.6 ⫾ 1.84 D ⫺3.0 D ⫺1.5 D ⫺1.8 D ⫺0.38 D ⫺1.01 D ⫺7.35 ⫾ 3.51 D
Journal of AAPOS Volume 6 Number 4 August 2002
Vanathi et al
Final
Change in axial length (mm)
Axial length difference between 2 eyes (mm)
IOP in affected eye (fellow eye) mm Hg
21.3 22.8 22.8 23.8 24.7 23.6
23.52 24.4 24.6 24.26 27.69 27.58
2.26 1.6 1.8 1.62 3 4
1.7 1 NA 1.16 3.39 3.5
14 (14) 14 (14) 17 (16) 15.6 (14.6) 17 (16) 16 (15)
⫺10.25
21.8
25.4
3.6
3
14 (14)
⫺6.75 —
22.8 22.5
26.6 24.53
3.8 2
3.2 1.8
⫺4
22.4
24.33
1.9
⫺3.5
23.1
25.4
⫺9.25
—
24.3
Axial length (mm)
Dioptric change ref error
Initial
⫺6.5 ⫺4.75 ⫺5 ⫺8.5 — ⫺15
⫺7.35 ⫾ 3.51
Final optical rehabilitation
231
Final visual acuity 6/12 6/18 6/18 6/36 6/18 6/12
14 (14) 17 (16)
Contact lens & # Spectacles ## Contact lens & # Contact lens & # Contact lens & # IOL removal & spectacles## Spectacles #, IOL removal advised Contact lens # PK advised
1.53
18 (18)
Contact lens & #
6/12
2.3
2.2
19 (18)
Contact lens & #
6/36
—
1.8
15.6 (14.6)
Contact lens & #
6/24
2.53 ⫾ 0.9
2.2 ⫾ 0.91
0.58 ⫾ 0.51
or without IOL implantation in some children. The pathogenesis of increased axial growth following unilateral cataract extraction is not clearly understood. The phenomenon of globe elongation has been attributed to be influenced by refractive blurs26-30 in developing eyes, intraocular pressure variations,31,32 and scleral changes.33,34 All patients with good visual acuity in our series had been given appropriate near vision correction for near and distance at all follow-ups. Hence the influences of refractive blur being responsible for the axial elongation of the globe, in our series, can be excluded. Our patients had a mean intraocular pressure difference of 0.58 ⫾ 0.51 mm Hg between the 2 eyes. Intraocular pressure changes below threshold values for glaucoma can influence ocular length in growing eyes.31,32 Subtle intraocular changes as a cause for progressive globe elongation remains to be considered. Further prospective studies with a larger case series are recommended to evaluate this possibility. Our series, being small and a retrospective analysis, has its limitations that no definite conclusion can be drawn regarding the possible mechanisms for this phenomenon of progressive ipsilateral axial elongation of the globe and no conclusions can be derived regarding the incidence of this progressive myopic phenomenon. Multiple factors including age at surgery, ocular trauma, laterality (unilateral cases), duration and severity of form vision deprivation, amblyopia, IOL implantation, multiple ocular surgeries, intraocular pressure changes, and altered scleral rigidity perhaps play a significant role in this phenomenon.
1/60 6/24 —
References 1. Beller R, Hoyt CS, Marg E, Odom JV. Good visual function after neonatal surgery for congenital monocular cataracts. Am J Ophthalmol 1981;91:559-65. 2. Greg FM, Parks MM. Stereopsis after congenital monocular cataract extractions. Am J Ophthalmol 1992;114:314-7. 3. Birch EE, Swanson WH, Stager DR, Woody M, Everett M. Outcome after very early treatment of dense congenital unilateral cataract. Invest Ophthalmol Vis Sci 1993;34:3687-99. 4. Birch EE, Stager DR. The critical period for surgical treatment of dense congenital unilateral cataract. Invest Ophthalmol Vis Sci 1996; 37:1532-8. 5. Brown SM, Archer S, Del Monte MA. Stereopsis and binocular vision after cataract surgery for unilateral infantile cataract. JAAPOS 1999;3:1-5. 6. Sinskey RM, Amin PA, Lingna R. Cataract extraction and intraocular lens implantation in an infant with a monocular congenital cataract. J Cataract Refract Surg 1994;20:647-51. 7. Ben Ezra D. Cataract surgery and intraocular lens implantation in children. Am J Ophthalmol 1996;121:224-5. 8. Dahan E, Drusedau MU. Choice of lens and dioptric power in paediatric pseudophakia. J Cataract Refract Surg 1997;23(suppl 1): 618-23. 9. Spierer A, Desatrik H, Blumenthal M. Refractive status in children after long-term follow-up of cataract surgery with intraocular lens implantation. J Pediatr Ophthalmol Strabismus 1999;36:25-9. 10. Awner S, Buckley EG, De Varo JM, Seaber JH. Unilateral pseudophakia in children under 4 years. J Pediatr Ophthalmol Strabismus 1996;33:230-6. 11. Lambert SR, Buckley EG, Plager DA, Medow NB, Wilson ME. Unilateral intraocular lens implantations during the first 6 months of life. JAAPOS 1999;3:344-9. 12. Knight-Nanan D, O’Keefe M, Bowell R. Outcome and complications of intraocular lenses in children with cataract. J Cataract Refract Surg 1996;22:730-6.
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13. Zhang Z, Li S. The visual deprivation and increase in axial length in patients with cataracts. Yen Ko Hsuch Pao 1996;12:135-7. 14. Enyedi LB, Peterseim MW, Freedman SF, Buckley EG. Refractive changes after pediatric intraocular lens implantation. Am J Ophthalmol 1998;126:772-81. 15. Gordon RA, Donzis PB. Refractive development of the human eye. Arch Ophthalmol 1985;103:785-9. 16. Larsen JS. The sagittal growth of the eye. Ultrasonic measurement of the axial length of the eye from birth to puberty. Acta Ophthalmologica 1971;49:873-86. 17. Leseur L, Arne JL, Chapotat E. Predictability of intraocular lens power calculation in the treatment of cataracts in children. J Fr Ophthalmol 1999;22:209-12. 18. McClatchy SK, Parks MM. Myopic shift after cataract removal in childhood. J Pediatr Ophthalmol Strabismus 1997;34:88-95. 19. Sorkin JA, Lambert SR. Longitudinal changes in axial length in pseudophakic children. J Cataract Refract Surg 1997;23:624-8. 20. Calossi A. Increase in axial length in infantile traumatic cataract. Optom Vis Sci 1994;71:386-91. 21. Kora Y, Shimuzu K, Inatomi M, Fukado Y, Ozawa T. Eye growth after cataract extraction and intraocular lens implantation in children. Ophthalmic Surg 1993;24:467-75. 22. Hutchinson AK, Wilson ME, Saunders RA. Outcomes and ocular growth rates after intraocular lens implantation in the first 2 years of life. J Cataract Refract Surg 1998;24:846-52. 23. Flitcroft DI, Knight-Nanan D, Bowell R, Lanigan B, O’Keefe M. Intraocular lenses in children: changes in axial length, corneal curvature and refraction. Br J Ophthalmol 1999;83:265-9. 24. Kugelberg U, Zetterstrom C, Syren Nordquist S. Ocular axial length
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33. 34.
in children with unilateral congenital cataract. Acta Ophthalmol Scand 1996;74:220-3. Griener ED, Dhan E, Lambert SR. Effect of age at the time of cataract surgery on subsequent axial growth in infant eyes. J Cataract Refract Surg 1999;25:1209-13. Schaeffel F, Howland HC. Mathematical model of emmetropization in the chicken. J Opt Soc Am A 1988;5:2080-6. Schaeffel F, Glasser A, Howland HC. Accomodation, refractive error and eye growth in chickens. Vis Res 1988;28:639-57. Irving EL, Callender MG, Sivak JG. Inducing myopia, hyperopia and astigmatism in chicks. Optom Vis Sci 1991;68:364-368. Wildsoet C, Wallmann J. Choroidal and scleral mechanisms for compensation for spectacle lenses in children. Vis Res 1995;35:117594. Medine A. A model for emmetropization predicting the progression of ametropia. Ophthalmologica 1987;194:133-9. Papastergiou GI, Schmid GF, Riva CE, Mendel MJ, Stone RA, Laties AM. Ocular axial length and choroidal thickness in newly hatched chicks and one-year-old chickens fluctuate in a diurnal pattern that is influenced by visual experience and intraocular pressure. Exp Eye Res 1998;66:195-205. Nickla DL, Wildsoet C, Wallman J. The circadian rhythm in intraocular pressure and its relation to diurnal ocular growth changes in chicks. Exp Eye Res 1998;66:183-93. Phillips JR, McBrien NA. Form deprivation myopia: elastic properties of the sclera. Ophthalmic Physiol Opt 1995;15:357-62. Wallmann J. Retinal influences on sclera underlie visual deprivation amblyopia. Ciba Found Symp 1990;155:126-34; discussion 135-41.
An Eye on the Arts – The Arts on the Eye
But for those first affections, Those shadowy recollections, Which, be they what they may, Are yet the fountain-light of all our day, Are yet a master-light of all our seeing; Uphold us, cherish, and have power to make Our noisy years seem moments in the being Of the Eternal Silence: truths that wake, To perish never: Which neither listlessness, nor mad endeavor, Nor man nor boy, Nor all that is at enmity with joy, Can utterly abolish or destroy! —William Wordsworth (from “Ode: Intimations of Immortality”)