KERATOKONUSLU HASTALARDA ÖN SEGMENT PARAMETRELERİNİN PENTACAM CİHAZI İLE DEĞERLENDİRİLMESİ

Öz

AMAÇ: Keratokonus hastalarında hastalığın şiddetine göre ön segment parametrelerinde gözlenen değişikliklerin Pentacam cihazı kullanılarak değerlendirilmesi ve elde edilen ölçümlerin sağlıklı bireylerden elde edilen ölçümler ile karşılaştırılması amaçlanmıştır.
GEREÇ VE YÖNTEM: Elli iki keratokonus hastasının 104 gözü ile 60 sağlıklı bireyin 120 gözüne ait Pentacam cihazı verileri retrospektif olarak değerlendirildi. Hastaların demografik özellikleri, korneal ön yüzey ve arka yüzeye ait kurvatür, asferite ve elevasyon değerleri (K1, K2, korneal astigmatizma ve ortalama asferite) ile en ince korneal kalınlık (TCT), apeks korneal kalınlık (ACT), korneal volüm (CV), ön kamara derinliği (ACD), ön kamara açısı (ACA) ve ön kamara volümü (ACV)değerleri kaydedildi.
BULGULAR: Keratokonus grubunda (22 Kız, 30 Erkek) ortalama yaş 30.8±11.6 yıl, kontrol grubunda (26 Kız, 34 Erkek) 32.4±12.4 yıl idi. Gruplar yaş ve cinsiyet açısından uyumlu idi (sırasıyla p=0.32, p=0.89). Keratometri değerlerine göre yapılan sınıflamaya göre keratokonus seviyesi 63 göz hafif, 26 göz orta ve 15 gözde ağır keratokonus olarak gruplandı. Keratokonus hastalarında gruplar arasında korneal ön yüzey ve arka yüzeye ait kurvatür, asferite ve elevasyon değerlerinde anlamlı fark bulundu (p<0.001). TCT hafif grupta en yüksek, ağır grupta en düşük saptandı ve gruplar arasındaki fark anlamlı idi (p<0.05). ACD hafif grupta 3.21±0.34, orta grupta 3.27±0.26 ve ağır grupta ise 3.79±0.53 idi ve aradaki fark anlamlı bulundu (p<0.05).
SONUÇ: Keratokonus progresyonu ile korneal ön yüzey ve arka yüzeye ait kurvatür, asferite ve elevasyon değerleri ile kornea ön segment parametrelerinde anlamlı değişiklikler gözlenmektedir.

Anahtar Kelimeler

• Anterior segment parameters
• asphericity
• corneal topography
• irregular astigmatism
• keratoconus.

EVALUATION OF ANTERIOR SEGMENT PARAMETERS IN PATIENTS WITH KERATOCONUS WITH PENTACAM DEVICE

Öz

OBJECTIVE: It was aimed to evaluate the changes observed in the anterior segment parameters in patients with keratoconus using Pentacam device according to the severity of the disease and to compare the determined results with those obtained from the healthy individuals.
MATERIAL AND METHODS: The data obtained by the Pentacam device for 104 eyes of 52 keratoconus patients and 120 eyes of 60 healthy individuals were retrospectively evaluated. Demographic features of the patients, the corneal curvature of the anterior and posterior surface, the asphericity and the elevation values (K1, K2, corneal astigmatism, and average asphericity), thinnest corneal thickness (TCT), apex corneal thickness (ACT), corneal volume (CV), anterior chamber depth (ACD), anterior chamber angle (ACA), and anterior chamber volume (ACV) outcomes were recorded.
RESULTS: The average age was 30.8±11.6 years in the Keratoconus group (22 Female, 30 Male) and 32.4±12.4 years in the control group (26 Female, 34 Male). The groups were compatible with each other in terms of age and gender (p=0.32, p=0.89, respectively). In the classification based on keratometry readings, keratoconus level was grouped as mild in 63 eyes, medium in 26 eyes, and severe in 15 eyes. In keratoconus patients, there was a significant difference in curvature, asphericity, and elevation values of the corneal anterior and posterior surfaces between the groups (p<0.001). TCT was the highest in the mild group and lowest in the severe group, and the difference between the groups was significant (p<0.05). ACD was 3.21±0.34 in the mild group, 3.27±0.26 in the medium group, and 3.79±0.53 in the severe group, and the difference was also significant (p<0.05).
CONCLUSIONS: Significant changes in the values of curvature, asphericity, and elevation of both corneal anterior and posterior surfaces and the parameters of the anterior segment of the cornea are observed with the progression of keratoconus.

Anahtar Kelimeler

• Anterior segment parameters
• Asphericity
• Corneal topography
• Irregular astigmatism
• Keratoconus

Destekleyen Kurum

The study did not receive any financial support.

Teşekkür

None

Kaynakça

1. 1. Arnalich-Montiel et al. Corneal surgery in keratoconus: which type, which technique, which outcomes? Eye and Vision. 2016;3(2):1-14.
2. 2. Najmi H, Mobarki Y, Mania K et al. The correlation between keratoconus and eye rubbing: a review. Int J Ophthalmol. 2019; 12(11):1775-1781.
3. 3.Barnett M, Mannis MJ. Contact lenses in the management of keratoconus. Cornea. 2011;30(12):1510-6.
4. 4. Nilagiri VK, Metlapally S, Kalaiselvan P, Schor MC, Bharadwaj RS. LogMAR and Stereoacuity in Keratoconus Corrected with Spectacles and RGP Contact Lenses. Optom Vis Sci. 2018; 95(4): 391–398.
5. 5. Kubaloglu A, Sari ES, Cinar Y, Koytak A, Kurnaz E, Özertürk Y. Intrastromal corneal ring segment implantation for the treatment of keratoconus. Cornea. 2011;30(1):11-7.
6. 6. Mazzotta C, Caporossi T, Denaro R, et al. Morphological and functional correlations in riboflavin UV A corneal collagen cross-linking for keratoconus. Acta Ophthalmol. 2012;90:259–265.
7. 7. Barr JT, Wilson BS, Gordon MO, et al. CLEK Study Group. Estimation of the incidence and factors predictive of corneal scarring in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study. Cornea. 2006;25(1):16-25.
8. 8. Santhiago MR, Giacomin NT, Smadja D, Bechara SJ. Ectasia risk factors in refractive surgery. Clin Ophthalmol. 2016;10:713-720.

9. 9. Sanctis U, Loiacono C, Richiardi L, Turco D, Mutani B, Grignolo FM. Sensitivity and specificity of posterior corneal elevation measured by Pentacam in discriminating keratoconus/ subclinical keratoconus. Ophthalmology. 2008; 115:1534–1539.
10. 10. Huseynli S, Borges JS and Alio LJ. Comparative evaluation of Scheimpflug tomography parameters between thin non-keratoconic, subclinical keratoconic, and mild keratoconic corneas. European Journal of Ophthalmology. 2018; 28(5): 521–534.
11. 11. McMahon TT, Szczotka-Flynn L, Barr JT, et al, CLEK Study Group. A new method for grading the severity of keratoconus the Keratoconus Severity Score (KSS). Cornea. 2006;25: 794–800.
12. 12. Michael W, Ovette F, Renato R. Tomographic Parameters for the Detection of Keratoconus. Eye & Contact Lens. 2014; 40(6):326-330.
13. 13.Vazquez PR, Galletti JD, Minguez N, et al. Pentacam Scheimpflug tomography findings in topographically normal patients and subclinical keratoconus cases. Am J Ophthalmol. 2014; 158(1): 32–40.
14. 14. Sherwin T, Brookes NH. Morphological changes in keratoconus: pathology or pathogenesis. Clin Exp Ophthalmol. 2004; 32: 211–217.
15. 15. Ucakhan OO, Ozkan M, Kanpolat A . Corneal thickness measurements in normal and keratoconic eyes: pentacam comprehensive eye scanner versus noncontact specular microscopy and ultrasound pachymetry. J Cataract Refract Surg. 2006;32(6):970–977.
16. 16. Binder PS, Lindstrom RL, Stulting RD, et al. Keratoconus and corneal ectasia after LASIK. J Refract Surg. 2005;21(6):749.
17. 17. Randleman JB, Russell B, Ward MA, Thompson KP, Stulting RD. Risk factors and prognosis for corneal ectasia after LASIK. Ophthalmology. 2003;110(2):267–275.
18. 18. Giri P, Azar DT. Risk profiles of ectasia after keratorefractive surgery. Curr Opin Ophthalmol. 2017;28(4):337-342.
19. 19. Pin˜ero DP, Alio´ JL, Aleso´n A, Vergara ME, Miranda M. Corneal volume, pachymetry, and correlation of anterior and posterior corneal shape in subclinical and different stages of clinical keratoconus. J Cataract Refract Surg. 2010; 36(5):814–825.
20. 20.Ucakhan OO, Cetinkor V, Ozkan M, Kanpolat A. Evaluation of Scheimpflug imaging parameters in subclinical keratoconus, keratoconus, and normal eyes. J Cataract Refract Surg. 2011;37(6):1116–1124.
21. 21. Budo C, Bartels MC, Van Rij G. Implantation of Artisan toric phakic intraocular lenses for the correction of astigmatism and spherical errors in patients with keratoconus. J Refract Surg. 2005; 21:218–222.
22. 22. Leccisotti A, Fields SV. Angle-supported phakic intraocular lenses in eyes with keratoconus and myopia. J Cataract Refract Surg. 2003; 29:1530–1536.
23. 23. Ramin S, Sangin Abadi A, Doroodgar F, et al. Comparison of Visual, Refractive and Aberration Measurements of INTACS versus Toric ICL Lens Implantation; A Four-year Follow-up. Med Hypothesis Discov Innov Ophthalmol. 2018;7:32–39.
24. 24. Çağıl N, Çakmak HB, Uğurlu N, et. al Corneal Volume Measurements with Pentacam for Detection of Keratoconus and Subclinical Keratoconus. Turk J Ophthalmol. 2013;43:77-82.
25. 25. Emre S, Doganay S, Yologlu S. Evaluation of anterior segment parameters in keratoconic eyes measured with the Pentacam system. J Cataract Refract Surg. 2007;33:1708-1712.
26. 26. Ambrosio R, Alonso RS, Luz A, Coca Velarde LG . Corneal-thickness spatial profile and corneal-volume distribution: tomographic indices to detect keratoconus. J Cataract Refract Surg. 2006;32(11):1851–1859.
27. 27. Smolek MK, Klyce SD. Is keratoconus a true ectasia? An eval-uation of corneal surface area. Arch Ophthalmol. 2000; 118: 1179 –1186.
28. 28. Rabsilber TM, Khoramnia R, Auffarth GU. Anterior chamber measurements using Pentacam rotating Scheimpflug camera. J Cataract Refract Surg. 2006; 32:456–459.
29. 29. M. Safarzadeh, N. Nasiri. Anterior segment characteristics in normal and keratoconus eyes evaluated with a combined Scheimpflug/Placido corneal imaging device. Journal of Current Ophthalmology. 2016; 28: 106-111.
30. 30. Koc M, Tekin K, Tekin MI, et al. An Early Finding of Keratoconus: Increase in Corneal Densitometry. Cornea. 2018; 0: 1–7.
31. 31. Velázquez JS, Cavas F, Piñero DP, Cañavate FJ, Barrio JA, Alio J. Morphogeometric analysis for characterization of keratoconus considering the spatial localization and projection of apex and minimum corneal thickness point. Journal of Advanced Research. 2020; 24: 261–271