AIM: To evaluate intraocular lens power (IOL) calculation and biometry before and 3mo after implantation of Keraring 355° intrastromal corneal ring segment (ICRS;Mediphacos, Belo Horizonte, Brazil) in keratoconic eyes.METHODS: In this cohort study, data of 19 keratoconus eyes of 18 patients which undergone ICRS implantations were gathered before and 3mo after surgery.Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), manifest refraction, IOL power calculation formulas, axial lenght (AL) and keratometry were analayzed.RESULTS: Mean age of participants was 29.58±0.6.UCVA improved from 0.84 (0.35) logMAR to 0.43 (0.31) logMAR significantly (P<0.001).BCVA and AL didn`t change significantly after 3mo.All Sphere, cylinder and spherical equivalent (SE) were improved significantly (P<0.001).On the other hand, keratometry 1 (K1) and keratometry 2 (K2) decreased significantly.It was a considerable change in SRK/Ⅱ (P<0.001), Hoffer Q (P<0.001) and Holladay Ⅰ(P<0.001) after 3-month`s follow-up.Among this formula SRK/II had the lowest change.CONCLUSION: In addition to improvement in visual, refractive, and keratometry outcomes after Keraring implantation, there was a significantly changes in IOL calculation formulas values.However, ICRS procedure doesn`t interfere considerably AL in eyes, but it seems reduced keratometric values lead to IOL power calculations more accurately and all formulas suggested same IOL power.

AIM: To evaluate association between mutations in the visual system homeobox 1 (VSX1) gene and keratoconus (KCN) complicated with granular corneal dystrophy (GCD), direct sequencing was performed in an Iranian family affected by KCN and GCD in four generations.METHODS: An Iranian pedigree with keratoconus spanning four generations along with GCD was identified.Whole blood sample was used for genomic DNA extraction.The molecular analysis by using polymerase chain reaction (PCR) of the entire coding region and intron-exon boundaries of VSX1 gene was preformed to investigate the possible linkage between KCN and GCD.Subsequently, direct sequencing was used for PCR products and mutation analysis was conducted in the patients and controls.RESULTS: Mutation analysis in VSX1 gene did not detect evidence for association between KCN and GCD diseases and VSX1 gene.Our data excluded VSX1 as the disease-causing gene for KCN/GCD in this specific pedigree.CONCLUSION: Despite of no association between KCN patients with GCD and VSX1 gene variations, other probable genes involved in pathogenesis of the KCN and GCD diseases need to be investigated in the patients.

AIM: To compare the anterior and posterior corneal astigmatism and total refractive astigmatism before and after MyoRing implantation in keratoconus(KCN)patients.METHODS: In this historical cohort study, the preoperative and postoperative total refractive, anterior and posterior corneal astigmatism of KCN patients implanted with a 360-degree full-ring implant(MyoRing)were compared before and after four consecutive follow-up sessions at 3, 6, 9, and 12 mo after surgery.RESULTS: The study encompassed 79 KCN patients(85 eyes), comprising 43 males and 36 females. The mean age of the patients was 29±7.41 years, ranging from 17 to 48 years. Throughout the follow-up sessions, a gradual decrease was observed in the trend of changes for total refractive astigmatism, anterior corneal astigmatism, and posterior corneal astigmatism. Postoperatively, total refractive astigmatism measurements exhibited a significant decrease of 2.09 D at 12 mo after MyoRing implantation(4.27±3.15 vs 2.18±1.63 D, P<0.001). Additionally, post-operative measurements revealed an enhancement of approximately 3.20 D and 0.59 D for anterior and posterior corneal astigmatism, respectively [6.40±1.90 vs 3.20±1.75 D for anterior corneal astigmatism(P<0.001)and 1.30±0.55 vs 0.71±0.35 D for posterior corneal astigmatism(P<0.001)].CONCLUSION: MyoRing implantation demonstrates significant improvements in astigmatism parameters, encompassing total refractive astigmatism as well as anterior and posterior corneal astigmatism.