Comparison of surgically induced astigmatic changes after cataract surgery in post-Laser in situ keratomileusis corneas versus virgin eyes

PURPOSE

Postoperative refraction in modern mi-croincision cataract surgery gained extra importance in patients with the previous laser-assisted in situ keratomileusis (LASIK) surgery. The surgically induced astigmatic changes in those eyes may differ not only in magnitude but also in direction compared to virgin corneas. This study aimed to compare the surgically induced astigmatic changes after microscopic cataract surgery between post-LASIK corneas and virgin eyes.

METHODS

Cases that underwent microincision cataract surgery in eyes with and without previous LASIK surgery were reviewed. The demographics, the axial length at cataract surgery, the central corneal thickness, spheric and cylindric values, keratometry readings, and postoperative posterior corneal astigmatism were retrospectively evaluated. A modified Alpins method was used for astigmatic vector analysis, and baseline astigmatism, surgically induced astigmatism, difference vector, flattening effect, and torque were assessed.

RESULTS

A total of 42 eyes from 24 subjects was evaluated. Group I consisted of 14 eyes with the previous LASIK, and Group II included 28 eyes without any refractive surgery. Preoperative mean central corneal thickness in Group I was significantly thinner (p=0.012). There was no significant difference in baseline astigmatism between the groups regarding magnitude and power vectors. After microincision cataract surgery, there were no significant differences in mean spheric and cylindric values and mean keratometry readings (all p>0.05). However, surgically induced astigmatism and difference vector were significantly higher on J45 vector component in post-LASIK eyes and microincision cataract surgery steepening effect on post-LASIK corneas was significantly higher than those in virgin eyes (p=0.001, p=0.002 and p=0.018, respectively).

CONCLUSIONS

Cataract surgery has steepened the corneas in both groups with a significantly higher steepening effect in post-LASIK eyes. Certainly, corneal topography cataract surgery is particularly helpful to provide more precise surgically induced astigmatism interpretations.

Choroidal vascularity index in pseudoexfoliative glaucoma

PURPOSE

To evaluate choroidal vascular involvement in pseudoexfoliative glaucoma (PEXG) by applying the choroidal vascularity index (CVI) to optic coherence tomography (OCT) images.

METHODS

Seventy-eight eyes from 40 subjects were included the study. Group 1 included healthy eyes (n = 20), group 2 eyes with PEX (n = 16), and group 3 eyes with PEXG (n = 42). OCT imaging of macular and peripapillary regions and retinal nerve fiber layer (RNFL) analyses were performed. CVI was calculated using ImageJ software.

RESULTS

The mean age was 64.89 ± 5.8, 71.2 ± 7.8, and 68.24 ± 7.4 years in groups 1, 2, and 3, respectively (p = 0.046). There were no significant differences between the groups in terms of sex (p = 0.777). In macula, mean CVI rates were 66.97 ± 1.9%, 64.23 ± 1.2%, and 64.63 ± 1.6%, and in the peripapillary areas, mean CVI rates were 67.04 ± 1.5%, 65.20 ± 1.5%, and 64.14 ± 2.1% in groups 1, 2, and 3, respectively (group 1 vs. group 2 and 3, p = 0.000; group 2 vs. group 3, p > 0.05). The decrease in average RNFL thickness was statistically significant in group 3 compared to groups 1 and 2.

CONCLUSION

CVI could be used to assess choroidal vascular changes in ocular diseases. CVI was found to be reduced in PEX and PEXG, indicating an ocular vascular involvement in pseudoexfoliative process.

Investigation of the Demodex Lid Infestation with in Vivo Confocal Microscopy versus Light Microscopy in Patients with Seborrheic Blepharitis

Aim: The comparison of the diagnostic efficiency of a reference method (light microscopy [LM] using 10% potassium hydroxide [KOH]) with the use of 100% alcohol to in vivo confocal microscopy (IVCM) for the detection of Demodex eyelid infestation in seborrheic blepharitis patients.Methods: Eyelashes were epilated from the right eyes for the reference method and the left eyes for the alcohol group in 58 eyes of 29 patients. IVCM was used on the left eyes. The primary outcomes were the number of Demodex mites per lash and the rate of Demodex positivity (≥1 mite).Results: The rate of Demodex positivity was similar among the three groups (KOH: 82.8%, alcohol: 86.2%, IVCM: 72.4%; p >.05). The mean number of mites per lash in the KOH group (1.5 ± 1.3) was higher than in the alcohol (0.9 ± 0.6, p =.041) and IVCM groups (0.9 ± 0.9, p =.036).Conclusion: KOH was found to be superior in terms of the quantification of mites compared to alcohol and IVCM.