Topografik Keratokonus Tarama Sýnýflamasý ile Görme Keskinliði, Refraksiyon ve Pakimetri Deðerleri Arasýndaki Ýliþki

GÝRÝÞ ve AMAÇ: Amacýmýz bilinen keratokonus (KK) tanýsý olmayan olgularda, görme keskinliði, refraktif ve pakimetrik parametreler ile topografik keratokonus tarama sýnýflamasýnýn (KKTS) iliþkisini deðerlendirmektir.
YÖNTEM ve GEREÇLER: Bu geriye dönük çalýþmada klinisyenlerin, KK’tan þüphelenerek, topografi tetkiki istediði 183 hastanýn 366 gözüne ait görme keskinliði, refraktif ve pakimetrik parametreler ile Sirius topografi (CSO, Frenze, Ýtalya) ile elde edilen KKTS sonuçlarý normal, þüpheli KK ve KK olarak geriye dönük not edilmiþtir. Gözlere ait astigmatik deðerler; < -1 D, -1 / -2 D, -2 / -4 D, and > -4 D olmak üzere dört gruba ayrýlmýþ ve KKTS ile bu gruplar arasýndaki iliþki deðerlendirilmiþtir.
BULGULAR: EÝDGK þüpheli KK grubunda normal gruba göre yüksek (p=0.008), KK grubunda normal ve þüpheli KK grubuna göre düþük (sýrasýyla
p=0.015, p<0.001) bulunmuþtur. SKK deðerleri þüpheli KK ve KK gruplarýnda normal gruba göre düþük (p<0.001), KK grubunda ise
þüpheli KK grubuna göre düþük (p<0.001) bulunmuþtur. Þüpheli KK ve KK gruplarýnda sferik refraktif deðerler normal grubuna göre yüksek (sýrasýyla p=0.03, p<0.001), KK grubunda þüpheli KK grubuna göre yüksek (p<0.001) bulunmuþtur. Astigmatik refraktif deðerler ve sferik eþdeðer (SE), KK grubunda normal ve þüpheli KK grubuna göre yüksek (p<0.001) bulunmuþtur. KK sýnýfýnda astigmatik deðeri 0/-1 D arasý ve -1/-2D arasý olan göz bulunma oraný düþük (p<0.05), > -4 D olan göz bulunma oraný yüksek saptanmýþtýr (p<0.05).
TARTIÞMA ve SONUÇ: Vizyonu refraksiyonla artmayan ve/veya SKK ince olan ve/veya yüksek astigmatizmasý olan hastalarda KK açýsýndan topografik deðerlendirme istenmelidir. Astigmatik refraktif deðeri -1 D’nin altýnda olan gözlerde de KKTS’nda þüpheli KK ve KK bulunma ihtimali mevcuttur, -4 D’den büyük olanlarda ise KK olarak iþaretlenme ihtimali artmaktadýr.

Relationship between Visual Acuity, Refraction and Pachymetry Values, and Topographic Keratoconus Screening Classification

INTRODUCTION: To evaluate the relationship between visual acuity, refractive and pachymetric parameters, and topographic keratoconus screening classification (KCSC) in patients without a known diagnosis of keratoconus (KC).
METHODS: This retrospective study included 366 eyes of 183 patients for whom topography examination was performed due to clinical suspicion of KC. Visual acuity, refractive and pachymetry parameters, and KCSC result (normal, suspect KC, or KC compatible) according to Sirius topography (CSO, Firenze, Italy) were noted retrospectively. The eyes were divided into 4 groups based on the magnitude of astigmatism (< -1 D, -1 to -2 D, -2 to -4 D, and > -4 D) and the relationship between these groups and topographic KCSC was evaluated.
RESULTS: BCVA was higher in the suspect KC group than in the normal group (p=0.008) and lower in the KC compatible group compared to the normal and suspect KC groups (p=0.015, p<0.001, respectively). CCT values were lower in the suspect KC and KC compatible groups
than in the normal group (p<0.001) and in the KC compatible group compared to the suspect KC group (p<0.001). Cylindrical values and spherical equivalent were higher in the KC compatible group than the normal and suspect KC groups (p<0.001). In the KC compatible group, fewer eyes had astigmatism of < -1 D or between -1 and -2 D (p<0.05), while significantly more eyes had astigmatism higher than -4 D (p<0.05).
DISCUSSION AND CONCLUSION: Patients whose vision did not improve with refraction, who had thin CCT, and/or high astigmatism should undergo topographic examination for KC. Eyes with cylindrical values less than -1 D may be classified as suspect KC or KC compatible, by topography while eyes with astigmatism higher than -4 D are more likely to be classified as KC compatible.