Long-term results of laser in situ keratomileusis for myopia

Laser in situ keratomileusis (LASIK) is still the most popular refractive surgery in the world. The aim of the study is to assess the long term clinical outcomes of LASIK in treating patients with different types of myopia. Pre- and postoperative distance visual acuity, refractive spherical equivalent (SE) and clinical examinations of dry eye disease were recorded. Values obtained at baseline and controls were compared with each other. While preoperative mean uncorrected distance visual acuity (UDVA) of low and moderate myopic patients was 0.1±0.07 on Snellen eye chart, and it was 0.86 ±0.11 at the 6th month and 0.92 ±0.05 at the 3rd year. At the last control examination, the percertages of manifest refractive SE in the range of ±0.50D and ±1.00D were 78.3%, 88.3%, respectively. The mean UDVA of high myopic patients was 0.03 ±0.02 preoperatively, and it was 0.84 ±0.16 at the 6th month and 0.69 ±0.21 at the 3rd year. UDVA at 3 years was significantly decreased compared with 6 month postoperatively.(p=0.01) At the last control examination of this group, the percentages of manifest refractive SE in the range of ±0.50D and ±1.00D were 48.3%, 66.1 %, respectively. These also decreased from 6 month to 3 years postoperatively.The mean tear break-up time and schirmer-1 values, which decreased in the postoperative first year visits of the patients, were close to the preoperative values at the last control. There were no statistically significant difference between the preoperative and 3rd year comparisons.(all p>0.05) In conclusion, LASIK is an effective and safe procedure in patient with myopia, preoperative higher SE is a predictor of low postoperative efficacy. [Med-Science 2023; 12(1.000): 197-03

Effects of rigid high gas-permeable contact lens wear on progression in patient with keratoconus

Wearing Rigid High Gas-Permeable Contact Lens (RGPCL) is a primary method of vision rehabilitation in keratoconus eyes. The aim of the study is to investigate the effects of using RGPCL on the topographical variations at the keratoconus progress. All patients had undergone ophthalmic examination including corneal topography, and their medical history and keratoconus characteristics were documented. Fifty-one eyes of those who wore RGPCL without any problems and 42 eyes of those who did not wear any lenses were evaluated retrospectively. It was accepted that the follow-up period was terminated when patients received any treatment or change lenses. The mean follow-ups were 36.5±12.7 and 38.4±14.6 months in the control and lens-wearing samples, respectively. The changes in topographic indices were compared from the baseline to the final visit. The difference between spectacle-best corrected visual acuity was not significant in both groups from baseline to final visit (p>0.05). In the RGPCL wearing group, apical keratometric power ( Kmax ) increased from mean 51.86±3.70 diopter (D) to 52.54±3.85 D at the sagittal map in the following period, but this difference was not significant (p>0.05). Similarly, in the control group, Kmax increased from mean 52.14±2.51 D to 52.94±3.02 D, and this difference was not significant (p>0.05). Lens-wearing and control group mean keratometry values increased from 47.36±1.7 D and 47.17±1.65 D to 47.94±2.05 D and 47.74±1.76 D, respectively (p>0.05). Pachymetry at the thinnest corneal point decreased significantly in both groups from baseline to final visit (p=0.008, p=0.01). In conclusion, the comfortable usage of RGPCL has no effect on the progression of keratoconus. [Med-Science 2022; 11(4.000): 1630-4

Comparison of anterior chamber depth measurements taken with the Pentacam, Orbscan IIz and IOLMaster in myopic and emmetropic eyes

This study determined to assess the degree of agreement between anterior chamber depth (ACD) measurements obtained using three different devices and to analyse the relationship between ACD and spherical equivalent (SE) refraction

Prevalence of Keratoconus and Subclinical Keratoconus in Subjects with Astigmatism Using Pentacam Derived Parameters

Purpose: To determine the prevalence of keratoconus (KCN) and subclinical KCN among subjects with two or more diopters (D) of astigmatism, and to compare Pentacam parameters among these subjects. Methods: One hundred and twenty eight eyes of 64 subjects with astigmatism ≥2D were included in the study. All subjects underwent a complete ophthalmic examination which included refraction, visual acuity measurement, slit lamp biomicroscopy, retinoscopy, fundus examination, conventional corneal topography and elevation-based topography with Pentacam. The diagnosis of KCN and subclinical KCN was made by observing clinical findings and topographic features; and confirmed by corneal thickness and elevation maps of Pentacam. Several parameters acquired from Pentacam were analyzed employing the Mann-Whitney U Test. Results: Mean age of the study population was 29.9±9.8 (range 15-45) years which included 39 (60.9%) female and 25 (39.1%) male subjects. Maximum corneal power, index of vertical asymmetry, keratoconus index and elevation values were significantly higher and pachymetry was significantly thinner in eyes with clinical or subclinical KCN than normal astigmatic eyes (P< 0.05). Conclusion: The current study showed that subjects with 2D or more of astigmatism who present to outpatient clinics should undergo corneal topography screening for early diagnosis of KCN even if visual acuity is not affected. Pentacam may provide more accurate information about anterior and posterior corneal anatomy especially in suspect eyes