Topographic Asymmetry Indices: Correlation between Inferior Minus Superior Value and Index of Height Decentration.

PURPOSE: To investigate the correlation between decentration index (index of height decentration, IHD) automatically calculated by the Pentacam HR software and the manually calculated inferior minus superior (I-S) value. SETTING: Al Watany Eye Hospital, Cairo, Egypt. METHODS: In a retrospective study, history taking, clinical examination, and rotating Scheimpflug camera scanning (by Oculyzer II equivalent to Pentacam HR) were done to 128 eyes: 82 normal, 24 forme fruste keratoconus FFKC (apparently normal cornea with evident keratoconus in the fellow eye), and 22 keratoconus (KC). All cases of corneal scars or previous corneal surgeries were excluded. The (I-S) value was calculated manually from 10 points astride the horizontal meridian. The IHD is calculated automatically by the device software 1.17r119. RESULTS: The mean (±SD) of (I-S) value in normal, FFKC, and KC eyes were 0.30 ± 0.93, 0.11 ± 2.03, and 4.62 ± 3.89, respectively, and those of IHD were 0.008 ± 0.004, 0.011 ± 0.005, 0.066 ± 0.067, respectively. The two indices were highly correlated (p < 0.0001) with a correlation coefficient (r 2 = 0.874). Deduced regression formulae linking the two indices were calculated. CONCLUSIONS: The two topographic decentration indices are highly correlated. Deduced formulae were proposed linking them.

New corneal assessment index from the relational thickness and other OCULUS values (CAIRO Index).

PURPOSE: The aim of this study was to find indices for keratoconus (KC) detection with higher sensitivity and specificity than the currently available ones with the rotating Scheimpflug imaging (Oculyzer I, Pentacam) software. PATIENTS AND METHODS: Data of 103 normal and 73 KC eyes imaged by Oculyzer I, including slit-lamp examination, refraction, Scheimpflug images, and follow-up data were collected. Logistic regression was done to find new indices with higher area under receiver operating characteristic curves using the currently available ones. RESULTS: The Corneal Assessment Index from Relational thickness and other OCULUS Values 9 (CAIRO 9) index, deduced from the Ambrosio relational thickness-maximum and the anterior elevation at thinnest point from 9 mm best-fit sphere, and the CAIRO 8, deduced from Ambrosio relational thickness-maximum and anterior elevation at thinnest point from 8 mm best-fit sphere, have a very high area under receiver operating characteristic curves for KC detection (0.997 and 0.995, respectively). CONCLUSION: New corneal assessment index is deduced with better sensitivity and specificity for KC detection.

Cap-preserving SMILE Enhancement Surgery.

BACKGROUND: Different enhancement procedures have been suggested for reduction of residual refractive errors after SMILE. The aim of this study is to evaluate an improved cap-preserving technique for enhancement after SMILE (Re-SMILE). METHODS: A retrospective case series was conducted at Eye subspecialty center, Cairo, Egypt on 9 eyes with myopia or myopic astigmatism (spherical equivalent - 8.0 and - 12.0D). undergoing SMILE procedure and needed second interference. This was either because the more myopic meridian was more than - 10.0 D and therefore planned to have two-steps procedure (six eyes) or because of under correction needing enhancement (three eyes). Assessment after the primary SMILE procedure was conducted at 1 day, 1 week, 1 month and 3 months postoperatively. Assessment after Re-SMILE was conducted at 1 day, 1 week, 1 month, 3 months, 6 months and 1 year postoperatively. The assessments included full ophthalmic examination, objective and subjective refraction, and rotating Scheimpflug camera imaging. RESULTS: Preoperatively, the mean refractive spherical equivalent (MRSE) values were: - 9.36 ± 0. 89. After primary SMILE it was - 2.18 ± 0.71. After Re-SMILE it was - 0.13 ± 0.68. MRSE was significantly improved after both procedures (P < 0.01). The safety index of primary SMILE cases was 1.65 ± 0.62 and for Re-SMILE 1.13 ± 0.34 and the efficacy index was 1.14 ± 0.24 after primary SMILE and 1.11 ± 0.26 after Re-SMILE. CONCLUSION: Centered cap-preserving Re-SMILE is an effective procedure in reducing residual refractive errors after primary SMILE in high myopes.

Dellen formation as a complication of subconjunctival silicone oil following microincision vitrectomy.

PURPOSE: To study the subconjunctival silicone oil (SCSO) parameters associated with dellen formation following microincision vitrectomy (MIV). PATIENTS AND METHODS: This was a case-control study of 20 eyes with SCSO following MIV. Ten of them suffered postoperative dellen formation. Dellen occurrence, their sizes, number of loci, and distance between SCSO and the limbus were recorded. The outcome after silicone-oil removal was evaluated. RESULTS: The SCSO was at 3.1±1.2 mm from the limbus. All cases with dellen had SCSO within 2 mm of the limbus (P<0.001). No other factors were found to be associated with dellen formation (age, P=0.414; sex, P=0.656; laterality, P=1; indication for pars plana vitrectomy, P=0.655; instrument gauge, P=0.211; circumference involved by SCSO, P=0.252). All the dellen healed after surgical evacuation of SCSO (P<0.001), leaving scars. CONCLUSION: Dellen can be associated with MIV secondary to SCSO near the limbus. Resolution with scarring occurred following SCSO evacuation. Therefore, SCSO should be evacuated as early as possible to avoid long-term peripheral corneal morbidity.

Microcapillary sign of flap alignment in femtosecond laser-assisted in situ keratomileusis.

We present an observational sign that ensures perfect alignment during femtosecond laser-assisted in situ keratomileusis (FS LASIK). Alignment is assured when a microsponge is used to dry the flap and the area of dryness exceeds the area of direct touch of the microsponge. The area might even reach the whole circumference of the flap at the first touch. This sign of alignment can be explained by microcapillary action. This sign was not elicited in flaps created by a microkeratome.

Rotating Scheimpflug Imaging Indices in Different Grades of Keratoconus.

Purpose. To evaluate accuracy of various Keratoconus (KC) screening indices, in relation to Topographic Keratoconus (TKC) grading. Setting. Al Watany Eye Hospital, Cairo, Egypt. Methods. Data of 103 normal (group 1) and 73 KC eyes (group 2), imaged by Pentacam (branded as Allegro Oculyzer), were analysed. Group 2 was divided into 2a: 14 eyes (TKC = 1, early KC), 2b: 25 eyes (TKC = 1 to 2 or 2, moderate KC), and 2c: 34 eyes (TKC = 2 to 3 up to 4, severe KC). Participants were followed up for six years to confirm diagnosis. Area under the receiver operating characteristic curve (AUROC) was calculated for evaluated curvature, elevation, and pachymetry indices with various reference shapes at different diameters. Results. When comparing normal to KC eyes, ten indices had significantly higher AUROC. Only five of them had significantly higher AUROC in early KC compared to normal corneas: Pachymetry Progression Index- (PPI-) Maximum (Max), Ambrósio's Relational Thickness- (ART-) Max, PPI-Max minus PPI-Minimum (Min), central corneal thickness (CCT), and diagonal decentration of thinnest point from the apex (AUROC = 0.690, 0.690, 0.687, 0.683, and 0.674, resp.). Conclusion. Generally, ten pachymetry and elevation-based indices had significantly higher AUROC. Five indices had statistically significant high AUROC when comparing early KC to normal corneas.