Physicians at the Department of Ophthalmology, University Hospitals of Leuven, Leuven, Belgium, and the Jules Stein Eye Institute, UCLA, Los Angeles, California, reviewed the records of 93 consecutive glaucoma patients who underwent sequential office IOP measurements (every hour from 7 a.m. to 5 p.m. on a single day). These included 53 patients with normal-tension glaucoma, 12 glaucoma suspects, and 28 patients with primary open-angle glaucoma, whose visual field deteriorated despite apparently, controlled IOP.
The pattern of the day-long IOP curve was similar in all three groups of patients, with IOP readings highest in the early morning hours. The mean ±SD of the IOP range was 5 ±2mmHg. An IOP > 21mmHg was found in three eyes (3 percent), while a range of IOPs > 5mmHg was observed in 33 eyes (35 percent). In the NTG group, there was a significant relationship between visual field deterioration and the peak and range of IOP (P = 0.0002 and P = 0.05, respectively).
The study confirms that IOP does vary during the course of the day, therefore the researchers conclude that performing day-long sequential office IOP measurements is useful for those selected patients who demonstrate progressive glaucomatous damage. They also conclude that early morning IOP measurements are most frequently highest, and as a result, the range of IOP may be as important, or more important than, the peak IOP level.
(J Glaucoma 2005; 14:196-200)
Collaer N, Zeyen T, Caprioli J.
New Perimeter More Sensitive Than Amsler Grid
THE PREFERNTIAL HYPERACUITY PERIMETER (PHP) has a greater sensitivity than an Amsler grid for detecting age-related macular degeneration, according to a clinical trial conducted by the PHP Research Group .
The study was conducted in 2001 at two Israeli medical centers and the Wilmer Eye Institute at the Johns Hopkins University. A total of 150 patients participated in the seven-month study. Participants in the study had to be at least 50 years of age. Visual criteria included best-corrected visual acuity letter score, using a protocol refraction with a Bailey-Lovie chart R and protocol VA measurement as used in the TAP (Treatment of Age-Related Macular Degeneration with Photo-dynamic Therapy) study with a Bailey-Lovie chart for OD or OS of at least the Snellen equivalent of >20/160, and healthy macula or AMD in the study eye.
|PHP vs Amsler Grid|
| Number Positive on PHP Positive on Amsler|
N (%) N (%)
|Neovascular AM 19 19 (100) 10 (53)|
|Geographic Atrophy 27 26 (96) 12 (44)|
|Intermediate AMD 20 14 (70) 4 (20)|
|Early AMD 51 21 (41) 4 (8)|
|No AMD 33 6 (18) 0|
The study results confirmed that the PHP had a greater sensitivity, although with a relatively high rate of false-positive results for healthy individuals, than the Amsler grid in detecting AMD-related lesions.
(Retina 2005; 25:296-303)
PHP Research Group
Sterility Decreased After 30-Day CL Wear
IN A STUDY DESIGNED TO ASCERTAIN THE EFFECTS of 30-day continuous-wear silicone hydrogel contact lenses on the conjunctival flora in asymptomatic wearers, researchers found that the number of sterile conjunctival cultures (pre-wear) significantly decreased (P=0.005) after wearing the lenses over the 30-day period. Additionally, the growth of coagulase-negative staphylococci and diphtheroid rods in conjunctival cultures also significantly increased (P=0.001 and P=0.031, respectively) after using the 30-day CW lenses.
Researchers in Turkey studied 29 eyes of 15 patients wearing 30-day continuous-wear Focus Night & Day contact lenses. Average age of the patients was 25.54 ±8.98 years (range, 10 to 43 years). Prior to lens wear, cultures were taken of each patient's inferior cul-de-sac. The same analysis was repeated in the same asymptomatic patients who had worn the 30-day CW Focus Night & Day contact lenses. Cultures of 29 eyes were compared before and after lens wear. Before lens wear 19 (65.52 percent) of 29 eyes had negative bacterial culture results and 10 (34.48 percent) of 29 eyes had positive bacterial cultures. However, after wearing the lenses for the 30-day period, 26 (89.66 percent) eyes had positive bacterial cultures (P=0.005), while only 3 (10.34 percent) of 29 eyes had negative bacterial culture results (P=0.005).
The researchers did add that contamination by the bacteria of the eyelids may be a possible colonization factor in the study group, and therefore conclude that patients who wear these lenses should be examined more frequently.
(Eye & Contact Lens 2005; 31(3):124-126)
Iskeleli G, Bahar H, Eroglu E, Torun M, Ozkan S.
Pachymetry Necessary Before LASIK
A THOROUGH PACHYMETRIC EVALUATION OF THE CORNEA before a LASIK procedure, with special attention to the inferotemporal area, is necessary, according to a Swedish study.
The focus of the study centered on determining if variations in the localization of the cornea's thinnest point, and whether corneas at risk for iatrogenic keratectasia, can be identified without a pachymetry map of the cornea. Three hundred eight eyes of 156 healthy volunteers with various refractive errors were examined with Orbscan II and autorefractometer-keratometer. The corneal thickness was registered at the fixation point, at the geometrical center, and at the thinnest point of the cornea.
Results showed that the thinnest point of the cornea was predominantly located in the inferotemporal quadrant, and was significantly thinner than the fixation point (539.6 ±35.8 µm and 548 ±35.4 µm, respectively, P<.001).
The study concludes that the absence of a clear relationship between the shape of the anterior corneal surface or the re-fractive error, and the shape of the posterior corneal surface, pachymetric evaluation of the cornea prior to LASIK is indicated. Special attention should be given to the inferotemporal area as well.
(J Cataract Refract Surg 2005; 31:701-706)
Jonsson M, Behndig A.
LASIK Alters Pupil Response
PUPIL DILATION AFTER TROPICAMIDE 1% INSTILLATION is significantly faster after LASIK surgery, according to a prospective study at Chicago's Northwestern University. Surgeons there performed LASIK on 19 eyes of 10 patients, taking measurements before and three months after the surgery. After instillation of tropicamide 1%, they measured the change in the pupil size over time with the Colvard pupillometer. They also assessed central corneal thickness by ultrasonic pachymetry at the same time points. Corneal epithelial condition was examined by fluorescein dye staining.
The mean CCT decreased significantly from 564 ±33µm (SD) before LASIK to 514 ±48µm three months postop. Pupil diameter at 10, 15 and 20 minutes after tropicamide 1% instillation was significantly larger three months postop compared to preop (P=.0083, P=.0043 and P=.0144, resp-ectively). Mean time to reach 6 mm of pupil dilation decreased significantly from 14.4 ±4.3 minutes in preop eyes to 11.5 ±2.3 minutes in postop eyes (P=.0281). Mild punctate corneal epithelial staining (fewer than five spots) was observed in four eyes at the three-month postop exam.
(J Cataract Refract Surg 2005; 31: 553-556.)
Chung HS, Feder RS.