Objective Assessment of Nuclear and Cortical Cataracts through Scheimpflug Images: Agreement with the LOCS III Scale.

PURPOSE: To assess nuclear and cortical opacities through the objective analysis of Scheimpflug images, and to check the correlation with the Lens Opacity Classification System III (LOCS III). METHODS: Nuclear and cortical opacities were graded according to the LOCS III rules after pupil dilation. The maximum and average pixel intensity values along an elliptical mask within the lens nucleus were taken to analyse nuclear cataracts. A new metric based on the percentage of opaque pixels within a region of interest was used to analyse cortical cataracts. The percentage of opaque pixels was also calculated for half, third and quarter areas from the region of interest's periphery. RESULTS: The maximum and average intensity values along the nucleus were directly proportional to the LOCS III grade: The larger the LOCS III value, the larger maximum and average intensity ones. These metrics showed a positive and significant correlation with the LOCS grade: The larger the LOCS grade, the higher was percentage of opaque pixels along the cortex within the same mask's size. This metric showed a significant correlation to the LOCS grade. CONCLUSION: The metrics used to assess nuclear opacities showed good correlation with the LOCS III. The percentage of opaque pixels showed to be a useful metric to measure objectively the severity of the cortical opacity. These metrics could be implemented in an algorithm to detect and grade lens opacities automatically and objectively.

Nepafenac 0.1% plus dexamethasone 0.1% versus dexamethasone alone: effect on macular swelling after cataract surgery.

PURPOSE: To evaluate the efficacy of adding nepafenac 0.1% ophthalmic suspension to dexamethasone 0.1% eyedrops in controlling macular swelling and other manifestations of inflammation after uneventful cataract surgery. SETTING: Ophthalmology Department, Mölndal Hospital, Gothenburg, and St. Erik Eye Hospital, Stockholm, Sweden. DESIGN: Randomized double-masked clinical trial. METHODS: Patients at low risk for postoperative inflammation were recruited and randomized to the nepafenac group or to the control group. Postoperative swelling of the macula was assessed with ocular coherence tomography. Laser flare intensity, corrected distance visual acuity, ocular discomfort, and visual complaints were also recorded. RESULTS: The analysis of intent-to-treat population comprised 75 patients in the nepafenac group and 77 patients in the control group. Compared with the control regimen, add-on nepafenac resulted in statistically significant reductions in the following parameters: change in macular volume at 3 weeks and 6 weeks (P<.001), proportion of patients with more than 10 µm of swelling in the central macula at 3 weeks (P<.0001) and 6 weeks (P=.02), mean laser flare intensity at 1 day (P=.029), pain during the first 24 hours postoperatively (P<.0001), and ocular discomfort and photophobia during the first 3 postoperative weeks (P=.0058 and P=.0052, respectively). CONCLUSION: The combination of topical nepafenac and steroid treatment reduced subclinical macular swelling and inflammation as well as subjective complaints, indicating it is an efficient antiinflammatory regimen after cataract surgery. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Rarebit perimetry and fovea test before and after cataract surgery.

PURPOSE: To evaluate the effect of cataract on rarebit perimetry and the fovea test. METHODS: Twenty-five consecutive patients scheduled for cataract surgery (mean age 63.0 +/- 7.9 years) were examined prior to and after cataract surgery with a complete ophthalmological examination. In addition, the rarebit perimetry (RBP) and the rarebit fovea test (RFT) were performed. RESULTS: Best-corrected visual acuity [BCVA, expressed in minimum angle of resolution (MAR)], RBP and RFT mean hit rate (MHR) improved significantly after cataract surgery. The relative pre-postsurgery difference was larger in the RFT [2.1 standard deviations (SDs)] compared to in BCVA (0.78 SDs). Seven patients had good BCVA (< or = 1.25) and RBP (83-99%) but low RFT (0-66%) before surgery. One patient with low preoperative BCVA (2.5) had a normal RFT (94%). CONCLUSION: Cataract influenced both the RFT and RBP test, albeit the former more than the latter. The influence of cataract on RFT results, even when visual acuity is decreased only moderately, has to be taken into account when evaluating foveal function in patients with cataract. The larger relative change in RFT compared to BCVA values is thought to indicate that RFT is more sensitive for the effect of cataract. Therefore, RFT appears to be a sensitive test for visual disturbance and can presumably provide additional information at the preoperative evaluation of the patient.

Evaluation of aqueous outflow facility in patients with high intraocular pressure after cataract surgery.

BACKGROUND AND OBJECTIVE: To study whether patients with a marked elevation of intraocular pressure (IOP) the day after cataract surgery may have a chronically impaired aqueous outflow. PATIENTS AND METHODS: In 128 consecutive patients, IOP was measured both preoperatively and the day after phacoemulsification and intraocular lens implantation. In the late postoperative period, aqueous outflow facility (C-value) was measured with pneumatonography in patients (n = 7) who experienced a postoperative IOP increase of at least 20 mm Hg and in patients (n = 11) with a difference between preoperative and postoperative IOP of not more than 2 mm Hg. RESULTS: Aqueous outflow facility was normal in both groups. Mean C-value was 0.32 +/- 0.18 microL/min/ mm Hg in the hypertensive group and 0.23 +/- 0.10 microL/ min/mm Hg in the normotensive group. The difference was not statistically significant (P = .20). CONCLUSIONS: Patients with marked IOP elevation the day after cataract surgery do not seem to have a chronically impaired aqueous outflow facility compared with normotensive patients.

Computer-simulated phacoemulsification.

OBJECTIVE: To develop a simulator for training in phacoemulsification to be used as a learning device for both beginners and experienced surgeons to shorten the learning curve. DESIGN: Experimental study. METHODS: The system consists of a personal computer, a 3-dimensional visual interface, a phacoemulsification handpiece, and a nucleus manipulator and foot pedals for control of the phacoemulsification procedure and microscope adjustments. The simulation is based on generalized simulation software that can be also used for the development of other medical simulations. MAIN OUTCOME MEASURES: Qualitative statements given in a questionnaire. Medical students and ophthalmic surgeons with varying experience of phacoemulsification were tested. RESULTS: A simulator for training in phacoemulsification has been developed. The surgical procedures can be practiced any number of times, and there is no risk to patients. The efforts of the surgeon can be evaluated objectively. CONCLUSIONS: Studies have shown that the number of complications for an ophthalmic surgeon learning phacoemulsification decreases exponentially, reaching close to the asymptote only after several hundred procedures. Simulator training might shorten the learning period, reduce expensive supervision by an experienced surgeon, and maintain and improve the skills of experienced surgeons.

Posterior capsule opacification after phacoemulsification in patients with postoperative steroidal and nonsteroidal treatment.

PURPOSE: To evaluate the effect of dexamethasone, diclofenac, and a placebo given for 3 weeks after phacoemulsification and intraocular lens (IOL) implantation on the formation of posterior capsule opacification (PCO). SETTING: St. Erik's Eye Hospital, Stockholm, Sweden. METHODS: In a 2-year prospective randomized double-blind study, a laser flare meter was used to measure aqueous flare intensity preoperatively and 3 days, 2 weeks, and 2 years after phacoemulsification and IOL implantation. Posterior capsule opacification was evaluated 2 years postoperatively using retroillumination images taken with a Scheimpflug camera. The Evaluation of Posterior Capsule Opacification system was used to score the areas of PCO density. RESULTS: The median rate of PCO 2 years after phacoemulsification was 0.72 (range 0.32 to 1.57) in the dexamethasone group, 0.78 (range 0.19 to 2.14) in the diclofenac group, and 0.70 (range 0.35 to 1.70) in the placebo group. The differences were not statistically significant (P>.05; Kruskal-Wallis analysis of variance, multiple comparisons). The rate of neodymium:YAG laser posterior capsulotomy during the 2 years after surgery was not statistically different between groups (P>.05, chi-square test). There was no correlation (Spearman rank coefficient) between laser flare measurements and PCO formation in any group during the study (P>.05). CONCLUSION: Topical instillation of diclofenac, dexamethasone, or a placebo in the immediate period after phacoemulsification and IOL implantation did not seem to influence the formation of PCO 2 years after cataract surgery.

Lacrimal drainage capacity, age and blink rate.

PURPOSE: The aim of this study was to investigate the influence of blink rate on lacrimal drainage capacity in different age groups. METHODS: The drop test for lacrimal drainage capacity was recently described by us. In the drop test, drops of 10 &mgr;l, 15 &mgr;l or 20 &mgr;l of lukewarm saline are repeatedly instilled in the tear film during three minutes. Excessive saline solution is then removed and the volume drained by the lacrimal passages is calculated. The drop test was performed in 40 individuals of two age groups, 10-30 years and 60-80 years. The drop test results were recorded when the subjects tried to blink at frequencies of 90 and 180 blinks/three minutes. RESULTS: The drop test results were significantly higher in the young than in the old subjects. At the lower blink rate, the lacrimal drainage capacity was 363 &mgr;l/3 min. in the young and 155 &mgr;l/3 min. in the old subjects. At the higher blink rate, the lacrimal drainage capacity was 520 and 200 &mgr;l/3 min., respectively. The increases in lacrimal drainage capacity with increasing blink rate were significant in both age groups. CONCLUSION: The lacrimal drainage capacity increased with increasing blink rate in both younger and older subjects. The lacrimal drainage capacity was significantly lower in the old age group at each blink frequency, indicating that other factors than blink rate are responsible for the lower lacrimal drainage capacity in older age.