Incidence Of Keratoconus In Candidates Of Refractive Surgery

Year 2007, Volume: 1 Issue: 3, 186 - 190, 20.11.2007

Nurullah Cagil

Abstract

Refractive surgical procedures include procedures that reduce refractive error like myopia, hyperopia, and astigmatism. All of these procedures are designed to minimize dependence on eyeglasses and contact lenses. Purpose of this study is to investigate the incidence of keratoconus in patients applying for refractive surgery.

Medical records of 286 patients applying to Refractive Surgery Unit of 1st Eye Clinic, Ankara Ataturk Education and Research Hospital were examined. Data regarding visual acuities, autorefractometry, keratometry, comeal topography, pachimetry, biomicroscopy, and fundus examination findings were retrieved from records of patients. Keratoconus diagnosis was established in patients with comeal topography and biomicroscopy findings of keratoconus. Keratoconus patients and other patients were compared for age, sex, amount of refractive error, and keratometry values.

Keratoconus diagnosis was established in 23 (8.1%) of cases. Of these, 8 (34.7%) were female and 15 (65.3%) were male, while 135 (51.3%) of normal cases were female and 128 (48.7%) were male.
here was significant difference between keratoconus ratios in females and males (p=0.045). Mean age of cases was 31.69+8.00 years in keratoconus group, and 31.53+.42 years in normal group, and there was no significant difference between groups (p=0.909). Mean manifest sphere value was -3.99±4.36 D in keratoconus, and -1.84±4.06 D in control group. Mean manifest cylinder value was -2.98±1.75 D in keratoconus, and -1.57±2.10 D in control group. Mean steep keratometry was 46.93+3.41 D in kerato-conus group, while it was 44.50±1.93 D in control group. Mean flat keratometry was 44.19±2.79 D in keratoconus, and 42.66±1.82 D in control group. Mean spherical equivalent value was -4.80+4.44 D İn keratoconus group, and -2.61+4.28 D in control group. There was significant difference between the two groups with respect to manifest sphere, manifest cylinder, steep and flat keratometry, and spherical equivalent values (p<0.005).

This study clearly indicates that keratoconus incidence is much higher in patients applying for refractive surgery compared to that reported in normal population. For this reason, careful preoperative examination of refractive surgery candidates from the aspect of kerato-conus seems to be mandatory for succesfull results.

Keywords

Refraktif cerrahi, keratokonus, Refractive surgery, keratoconus

Refraktif Cerrahi İçin Başvuran Hastalarda Keratokonus Sıklığı

Abstract

Refraktif cerrahi gözdeki miyopi, hipermetropi ve/veya astigmatizma gibi kırma kusurlarını düzelterek, net bir görmenin gözlük veya kontakt lens kullanmaksızın sağlanması amacıyla uygulanan bir cerrahi işlemdir. Çalışmamızda Refraktif cerrahi için başvuran hastalarda keratokonus sıklığını incelemeyi amaçladık.

Ankara Atatürk Eğitim ve Araştırma Hastanesi I. Göz Kliniği Refraktif Cerrahi birimine başvuran 286 hastanın dosyası incelendi. Olguların tümünde görme keskinliği, otorefraktrometre, keratometre, kornea topografısi, pakimetri, biyomikroskopi, fundus muayenesi bulguları kayıtlardan alındı. Kornea topografısi ve biyomikroskopi bulgulan keratokonus ile uyumlu olan olgular keratokonus olarak teşhis edildi. Keratokonus olguları ile diğer olgular yaş, cinsiyet, kırma kusuru miktarı ve keratometri değerleri yönünden karşılaştırıldı.

Olguların 23’ünde (%8.1) keratokonus teşhis edildi. Bu olguların 8’i (%34.7) kadın ve 15’i (%65.3) erkek iken normal olguların 135’i (%51.3) kadın ve 128’i (%48.7) erkekti. Erkek olgulardaki keratokonus oranı ile bayan olgulardaki keratokonus oranı arasında anlamlı fark vardı (p=0.045). Olguların ortalama yaşlan keratokonuslarda 31.69+8.00 yıl iken diğer olgularda 31.53±9.42 yıldı ve iki grup arasında anlamlı bir fark yoktu (p=0.909). Ortalama manifest sfer değerleri keratokonus grubunda -3.99+4.36 D, kontrol grubunda ise -1.84+4.06 D idi. Manifest silindir değerlerinin ortalaması keratokonus grubunda -2.98+1.75 D, kontrol grubunda ise -1.57±2.10 D idi. Dik aks keratometri değerlerinin ortalaması keratokonus grubunda 46.93+3.41 D, kontrol grubunda ise 44.50±1.93 D idi.

Ortalama düz aks keratometri değeri keratokonus grubunda 44.19+2.79 D, kontrol grubunda ise 42.66±1.82 D idi. Sferik eşdeğerlerin ortalaması, keratokonus grubunda -4.80+4.44 D, kontrol grubunda ise -2.61+4.28 D idi. İki grup arasında manifest sfer, manifest silindir, dik aks ve düz aks keratometri, ve sferik eşdeğerler yönünden anlamlı fark vardı (p<0.005)

Bu çalışmanın da açıkça gösterdiği gibi, refraktif cerrahi için başvuran hastalardaki keratokonus oranı normal nüfustaki bilinen orana göre çok daha yüksektir. Bu nedenle refraktif cerrahi için başvuran hastalarda başarılı sonuçlar elde etmek için keratokonus yönünden dikkatli bir preoperatif değerlendirmenin şart olduğu görülmektedir.

Keywords

Refraktif cerrahi, keratokonus, Refractive surgery, keratoconus

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