ABSTRACT
Conclusions:
There is no statistically significant difference in the effects of the pilocarpine induced accommodation with regard to cyloplegia on lens thickness between axial myopia and emmetropia.
Results:
The mean lens thickness under cyclopentolate was 3.78 ± 0.08 mm and 3.76 ± 0.10 mm in the axial myopia group and the control group, respectively. The mean lens thickness under pilocarpine was 3.96 ± 0.08 mm and 4.00 ± 0.08 mm in the axial myopia group and the control group, respectively. There was no statistically significant difference between the lens thickness of the axial myopia group and control group, under cyclopentolate (p>0.05) and pilocarpine (p>0.05), respectively. The mean increase in lens thickness after pilocarpine instillation with regard to cyloplegia was 0.20 ± 0.10 mm in the axial myopia group and 0.21 ± 0.10 mm in the control group. There was no statistically significant difference in increase in lens thickness after pilocarpine instillation with regard to cycloplegia between axial myopia and control gro-ups (p>0.05).
Methods:
Twenty-seven subjects with unilateral axial myopia and more than 3 diopters of difference in spherical equivalent between two eyes of each subject were included in the study. The mean age of the subjects was 27.3 ± 8.1 (range: 14 to 43) years. Both eyes of all sub-jects underwent axial length and lens thickness measurements with ultrasound biometry under cyclopentolate 1% and pilocarpine 2%, respectively. The eyes with axial myopia (study group) were compared with same subjects fellow (control group) eyes with lower axial length.
Purpose:
To compare the effects of the pilocarpine induced accommodation with regard to cyloplegia on lens thickness between axial myopia and emmetropia.
Keywords:
Axial myopia, lens thickness, accommodation
References
1Cheng HM, Singh O S, Kwong KK, et al. Shape of the myopic eye as seen with high-resolution magnetic reso- nance imaging. Optom and Vis Sci 1992; 69:698-670.
2Erdinç E, Asyalı ŞA, Demirbay DP, et al. Emetrop ve miyop gözlerde aksiyel uzunluk ve kornea refraktif parametrelerinin karşılaştırılması. MN Oftalmoloji 2001; 8:26-28.
3Takmaz T, Zilelioglu G, Yalçın E. Oküler refraktif parametreler. MN Oftalmoloji 1998; 5:315-317.
4Jones LA, Mitchell GL, Mutti DO, et al. Comparison of ocular component growth curves among refractive error groups in children. Invest Ophthalmol V is Sci 2005; 46:2317-2327.
5Atchison DA, Jones CE, Schmid KL, et al. Eye shape in emmetropia and myopia. Invest Ophthalmol Vis Sci 2004; 45:3380-3338.
6Tamm E, Lutjen-Drecoll E, Jungkunz W, et al. Posterior attachment of ciliary muscle in young, accommodating old, presbyopic monkeys. Invest Ophthalmol Vis Sci 1991; 32:1678-1692.
7Mutti DO, Sholtz RI, Friedman NE, et al. Peripheral ref- raction and ocular shape in children. Invest Ophthalmol Vis Sci 2000; 41:1022-1030.
8Croft MA, Kaufman PL. Accommodation and presbyo- pia: the neuromuscular view. Ophthalmol Clin North Am 2006; 19:13-24.
9Zadnik K, Mutti DO, Fusaro RE, et al. Longitudinal evi- dence of crystalline lens thinning in children. Invest Ophthalmol Vis Sci 1995; 36:1581-1587.
10Mutti DO, Zadnik K, Fusaro RE, et al. Optical and struc- tural development of the crystalline lens in childhood. In- vest Ophthalmol Vis Sci 1998; 39:120-133.
11van Alphen GWHM, Graebel WP. Elasticity of tissues in- volved in accommodation. Vision Res 1991; 31:14171438.
12Dubbelman M, van der Heijde GL, Weeber HA, et al. Changes in the internal structure of the human crystalline lens with age and accommodation. Vision Res 2003; 43:2363-2375.
13Glasser A, Kaufman PL. Accommodation and presbyo- pia. In: P. L. Kaufman, A. Alm, (Eds), Adler's Physio- logy of the Eye 2003: 195-233. St. Louis: Mosby.
14Gwiazda J, Thorn F, Bauer J, et al. Myopic children show insufficient accommodative response to blur. Invest Ophthalmol Vis Sci 1993; 34:690-694.
15Gwiazda J, Grice K, Thorn F. Response AC/A ratios are elevated in myopic children. Ophthalmic Physiol Opt 1999; 19:173-179.
16Mutti DO, Jones LA, Zadnik K. A C/A ratio, age, and ref- ractive error in children. Invest Ophthalmol Vis Sci 1998; 39:639.
17Mantyjarvi MI. Accommodation in hyperopic and myopic school children. J Pediatr Ophthalmol Strabismus 1987; 24:37-41.
18Rabie EP, Steele C, Davies EG. Anterior chamber pach- ymetry during accommodation in emmetropic and myopic eyes. Ophthalmic Physiol Opt 1986; 6:283-286.
19McBrien NA, Millodot M. Amplitude of accommodation and refractive error. Invest Ophthalmol Vis Sci. 1986; 27:1187-1190.
20Oliveira C, Tello C, Liebmann JM, et al. Ciliary Body Thickness Increases With Increasing Axial Myopia. Am J Ophthalmol 2005; 140:324-325.
21Glasser A. Accommodation: mechanism and measure- ment. Ophthalmol Clin North Am 2006; 19:1-12.
22Strenk SA, Semmlow JL, Strenk LM, et al. Age related changes in human ciliary muscle and lens: a magnetic re- sonance imaging study. Invest Ophthalmol Vis Sci 1999; 40:1162-1169.
23Ostrin LA, Glasser A. Accommodation measurements in a prepresbyopic and presbyopic population. J Cataract Refract Surg 2004; 30:1435-1444.
24Satıcı A, Çam V. Lens kalınlıgının yaş ve aksiyel uzunluk ile ilişkisi. T Klin Oftalmoloji 1998;7:163-168.
25Kriechbaum K, Findl O, Kiss B, et al. Comparison of anterior chamber depth measurement methods in phakic and pseudophakic eyes. J Cataract Refract Surg 2003; 29:8994.
26Weiss AH. Unilateral high myopia: optical components, associated factors, and visual outcomes. Br J Ophthalmol 2003; 87:1025-1031.
27Rajan MS, Keilhorn I, Bell JA. Partial coherence interfe- rometry vs conventional ultrasound biometry in intraocu- lar lens power calculations. Eye 2002; 16:552-556.
28Leaming DV. Practice styles and preferences of ASCRS members-1999 survey. J Cataract Refract Surg 2000; 26:913-921.
29Küçüksümer Y, Bayraktar Ş, Sayar A, Y ılmaz ÖF. Biyo- metri cihazlarında kataraktlı lens içinde ultrasonik dalganın ilerlerme hızı için farklı degerlerin kullnılmasının ameliyat sonrası istenilen refraksiyondan sapmaya etkisi. MN Oftalmoloji 2003; 10:102-106
30Findl O, Kriechbaum K, Sacu S, et al. Influence of opera- tor experience on the performance of ultrasound biometry compared to optical biometry before cataract surgery. J Cataract Refract Surg 2003; 29:1950-1955.
31Hennessy MP, Chan DG. Contact versus immersion biometry of axial length before cataract surgery. J Cataract Refract Surg 2003; 29:2195-2198.
32Giers U, Epple C.Comparison of A-scan device accuracy. J Cataract Refract Surg 1990; 16: 235-242.
33Norrby S, Lydahl E, Koranyi G, et al. Comparison of 2
34A-scans. J Cataract Refract Surg 2003; 29:95-99.Koeppl C, Findl O, Kriechbaum K, et al. Comparison ofpilocarpine-induced and stimulus-driven accommodation in phakic eyes. Exp Eye Res 2005; 80:795-800.
