Influence of deep scleral flap size on intraocular pressure after deep sclerectomy.

PURPOSE: To study the effect of several morphometric characteristics of the deep scleral flap on intraocular pressure (IOP) control after deep sclerectomy. METHODS: The authors conducted a nonrandomized prospective study of 56 eyes of 51 patients who underwent deep sclerectomy alone or combined with phacoemulsification. A reticulated hyaluronic acid implant was used in all cases. The surface, volume, and weight of the dissected deep scleral flap were measured and recorded. The correlation between these parameters and the postoperative IOP was evaluated at 6 and 12 months postoperatively. RESULTS: Forty-nine eyes (87.50%) achieved an IOP of 21 mmHg or less without treatment, and the need for medication was decreased significantly (p<0.001) at 12 months postoperatively. The authors found a significant inverse correlation between the mean postoperative IOP at 6 months and the surface, volume, and weight of the deep scleral flap, but not at 12 months postoperatively. CONCLUSIONS: Greater weight, surface area, and volume of the deep scleral flap dissected during deep sclerectomy achieve significantly lower postoperative IOPs in the early postoperative period.

Impression cytology of the conjunctival epithelium after antiglaucomatous treatment with latanoprost.

PURPOSE: To study nongoblet and goblet epithelial conjunctival cells after several treatment periods with latanoprost, a prostaglandin analogue. METHODS: Twelve patients (20 eyes) were studied before the onset of treatment and after 1, 3, and 6 months of latanoprost use. Impression cytology was carried out to analyze cellular density and morphologic parameters such as minimum and maximum diameter and area. RESULTS: Nongoblet epithelium cell density did not change over the treatment period. The density of goblet cells increased after 1 month of use, but returned to initial cell density after longer treatment periods. Nongoblet epithelial cells underwent a significant reduction in size after 1, 3, and 6 months of treatment. In addition, the minimum/maximum diameter ratio suggested that after 1 month there were some changes in shape (a slight elongation) when compared to cells of untreated patients. Nevertheless, after longer treatment periods, the cells regained their original shape. No changes in size were observed in goblet cells, except for a slight decrease in maximum diameter after 6 months of treatment, which suggests that the cells became more rounded. CONCLUSIONS: The density of nongoblet epithelial cells does not change after different treatment periods with latanoprost. However, their size decreases and after short treatment periods their shape also undergoes changes. The density of goblet cells increases after 1 month of treatment, but decreases again after longer periods. Their size does not undergo any modification, although there is a variation in shape after 6 months of treatment.

Changes in lamina cribrosa and prelaminar tissue after deep sclerectomy.

AIM: To determine the response of the lamina cribrosa (LC) and prelaminar tissue to a reduction of intraocular pressure (IOP) after nonpenetrating deep sclerectomy (NPDS) using enhanced depth imaging (EDI) spectral domain optical coherence tomography (SD-OCT). METHODS: A total of 28 eyes from 28 patients presenting with primary open angle glaucoma who underwent NPDS were studied. SD-OCT scans using EDI technology were obtained before surgery and 1 week, 1 month, and 3 months postoperatively. The OCT device was set to image a 15 × 10° vertical rectangle centred on the optic disc. The scan closest to the optic nerve head (ONH) centre was selected for analysis. The vertical distances from three equidistant points on the reference line (Bruch's membrane opening) to the anterior prelaminar tissue surface and the anterior and posterior surfaces of the LC were measured. RESULTS: The IOP decreased from 18.7 ± 4.3 to 9.1 ± 4.0 at the first week, 11.4 ± 3.7 at 1 month, and 13.1 ± 3.6 mm Hg at 3 months postoperatively (P<0.001). There was a significant reduction of the ONH cupping at 1 week (22.3%, P<0.001), 1 month (13.7%, P<0.001), and 3 months (9.8%, P=0.001) after surgery. Anterior displacement of the LC was slight but statistically significant at 1 week (4.5%, P=0.003), 1 month (3.8%, P=0.014), and 3 months postoperatively (3.3%, P=0.010). IOP reduction was significantly correlated with a reduction of ONH cupping and anterior displacement of LC at the first week and first month (P<0.05). CONCLUSIONS: Cupping reversal after NPDS is mainly due to changes in prelaminar tissue thickness, whereas the LC changes in position are less pronounced.

Cup-to-disc ratio: agreement between slit-lamp indirect ophthalmoscopic estimation and stratus optical coherence tomography measurement.

PURPOSE: To determine agreement between slit-lamp indirect ophthalmoscopy and Stratus optical coherence tomography (OCT) when assessing cup-to-disc ratios (CDRs). METHODS: Twenty-five ocular hypertensive subjects and 56 patients with primary open-angle glaucoma were included. Estimation of vertical (VCDR) and horizontal (HCDR) cup-to-disc ratio with slit-lamp ophthalmoscopy was made by three glaucoma specialists along with OCT scanning of optic nerve head. Agreement between OCT and specialists was measured by intraclass correlation coefficients (ICC), Bland and Altman's scatterplots, and a regression coefficient of the average difference. RESULTS: The mean VCDR and HCDR was significantly higher (P<0.001) with OCT than that estimated by the specialists, with the difference ranging from 0.08 to 0.11, and from 0.13 to 0.18, respectively, depending on the specialist. Difference was higher (P<0.001) for cuppings below 0.3, and looses significance for larger VCDR cuppings (above 0.7). ICC for VCDR was 0.87 among specialists, and ranges from 0.82 to 0.75 when comparing OCT and specialists. ICC for HCDR was 0.83 among specialists and 0.74 between OCT and specialists. When data were plotted according to the Bland-Altman method, as the cupping increased, the agreement also increased. CONCLUSIONS: There is very good agreement among the specialists when estimating CDRs by stereoscopic slit-lamp biomicroscopy. OCT shows higher values than the specialists; the greatest differences occurred when assessing small CDRs and the differences diminished as the cupping increased. These two methods of measurement are not interchangeable, and the difference must be considered, especially in discs with smaller CDRs.