Femtosecond thin-flap laser assisted in situ keratomileusis for correction of post-penetrating keratoplasty ametropia: long-term outcome

PURPOSE

To evaluate the long-term clinical outcomes of femtosecond thin-flap LASIK (femto-LASIK) for correction of refractive error after penetrating keratoplasty in keratoconus-affected eyes.

SETTING

a private ophthalmology clinic.

DESIGN

Prospective interventional case series.

METHODS

This prospective interventional case series enrolled 22 eyes of 22 patients who underwent femto-LASIK for the management of post-penetrating keratoplasty ametropia. The refractive error, uncorrected (UDVA), and corrected (CDVA) distance visual acuities and vector analysis were reported in short-term and long-term period after surgery.

RESULTS

The mean age was 32.7 ± 7.5 years (range, 23 to 47 years) at the surgery time. The average time between PK and femto-LASIK was 42.5 ± 31.7 months. The average follow-up duration after femto-LASIK was 81.2 ± 18.6 months. The mean preoperative UDVA significantly improved from 0.47 ± 0.15 logMAR to 0.35 ± 0.14 logMAR at 12 months (P = 0.048) and 0.4 ± 0.17 at final follow-up exam (P = 0.007). CDVA was 0.22 ± 0.1 at baseline which improved to 0.18 ± 0.15 and 0.15 ± 0.1 logMAR at 12 and 81 months, respectively. (Ps = 0.027, 0.014). The mean cylinder before surgery was - 5.04 ± 1.4D which significantly decreased to -1.5 ± 0.8 D at 12 months postoperatively. (P < 0.001). There was a significant increase in refractive astigmatism from 12 months to 81 months postoperatively (-3.1 ± 2.0, P = 0.002). At the final visit, the efficacy index was 0.83, and the safety index was 1.16.

CONCLUSIONS

Despite the short-term outcome indicated that femo-LASIK was effective for correction of post-keratoplasty ametropia during short-term period, a notable regression in its effect was observed in the long-term follow-up. Therefore, the predictability of this technique might decrease in the long-term.

Measurement of Central Corneal Thickness Using Ultrasound Pachymetry and Orbscan II in Normal Eyes

Purpose:

To compare ultrasound pachymetry and Orbscan II for measurement of central corneal thickness (CCT) in normal eyes.

Methods:

The current study was performed at Labbafinejad Medical Center (LMC), Tehran, Iran. Three hundred eyes from 150 healthy individuals referred for keratorefractive surgery were assessed first by Orbscan II and then by ultrasound pachymetry, and CCT values were recorded and compared.

Results:

Overall, Orbscan II overestimated CCT as compared to ultrasound pachymetry by about 2.4% (mean values 547.6 ± 34.7 versus 534.8 ± 34.7, respectively, P < 0.001). The difference was more significant when CCT was less than 500 microns (mean values 493.2 ± 16.9 versus 479.9 ± 15.6, mean overestimation: 2.6%, P < 0.001). There was good linear correlation between the two methods (Pearson's correlation r = 0.968, P < 0.0001).

Conclusion:

Orbscan II has good correlation with ultrasound pachymetry for measurement of CCT in normal eyes; however Orbscan II should not be used to evaluate corneal thickness before keratorefractive surgeries, as it tends to overestimate corneal thickness and may result in undesirable, low residual stromal thickness.

Serum levels of zinc, copper, vitamin B12, folate and immunoglobulins in individuals with giardiasis

BACKGROUND

Giardia lamblia is one of the most important intestinal parasites. The aim of this study was to measure serum levels of IgA, IgE, zinc, copper, vitamin B12 and folate in individuals with giardiasis in comparison to normal subjects.

METHODS

The study was carried out among 49 Giardia positive and 39 age and sex matched healthy volunteers. Examination of stool samples was done by direct wet smear and formol-ether concentration method. Serum samples were obtained for further laboratory examination. IgA levels were measured by Single Radial Immune Diffusion (SRID). IgE levels were measured by ELISA kit. Zinc and copper levels was measured by Ziestchem Diagnostics Kit and colorimetric endpoint-method respectively. Vitamin B12 and folate levels were measured by DRG Diagnostics Kit and Enzyme Immunoassay method respectively. All data were analyzed using SPSS version 17.

RESULTS

There was a statistically significant difference in IgA, IgE, copper and zinc levels between positive and negative groups (P<0.05). There was no significant difference between vitamin B12 and folate levels between the two groups. Mean values of Giardia positive and negative groups for IgA were 309.26 and 216.89 mg/dl, IgE 167.34 and 35.49 IU/ml, copper 309.74 and 253.61 μg/dl and zinc 69.41 and 144.75 μg/dl respectively.

CONCLUSION

The results showed levels of IgA may correlate more closely with giardiasis than IgE. Regarding trace elements, giardiasis elevated serum copper levels, while it decreased serum zinc. Finally, there was no significant difference in serum levels of vitamin B12 and folic acid between the two groups.

DNA-mobility shift assay and the detection of anti-DNA IgG in systemic lupus erythematosus patients

Although the presence of antibodies against double-stranded (ds) DNA is highly specific of systemic lupus erythematosus (SLE), it is not detected in all SLE patients, perhaps due to a lack of sensitivity of the tests routinely used to assay anti-(ds) DNA. Looking for an alternative assay, this study explored the applicability of a DNA-mobility shift assay for the detection of anti-(ds) DNA; furthermore, the study compared the use of Salmonella typhimurium DNA with that of calf thymus DNA in the assay. After electrophoresis, samples containing S. typhimurium DNA and IgG from SLE sera showed marked alterations in DNA electrophoretic mobility when compared to DNA alone. In our sampling, SLE patients who tested negative for anti-(ds) DNA antibodies with routinely used assays such as Crithidia luciliae immunofluorescence test, radioimmunoassay (RIA) or enzyme-linked immunosorbent assay (ELISA), tested positive for anti-(ds) DNA with the DNA mobility shift assay using S. typhimurium DNA. Incubation with IgG from control sera in the same proportions as above did not affect S. typhimurium DNA electrophoretic mobility. When S. typhimurium DNA was replaced by calf thymus DNA, the effect on the DNA mobility was less pronounced and less reliable. These results indicated that a DNA-mobility shift assay would be a useful alternative for the unequivocal detection of abnormal titers of anti-(ds) DNA antibodies. Furthermore, data indicated a greater ability of the IgG from SLE patients to form complexes with S. typhimurium DNA than with calf thymus DNA, suggesting an alternative testing DNA which may lead to a more sensitive anti-(ds) DNA detection.