Ocular optical quality changes in patients with different stages of glaucoma

Session Details

Session Title: Glaucoma II

Session Date/Time: Monday 15/09/2014 | 08:00-10:30

Paper Time: 09:27

Venue: Boulevard F (Level 1)

First Author: : J.Ondategui-Parra SPAIN

Co Author(s): :    L. Zahiño Lora   E. Arrondo   C. Pallars   F. Manero   J. Güell   J. Pujol Ramo

Abstract Details

Purpose:

One of the main problems in patients with primary open-angle glaucoma (POAG) is the absence of clinical symptoms in the early stages of the disease. The impairment of visual function in patients with glaucoma is usually not mentioned until the advanced stages of the disease, when damage is often devastating and irreversible. The aim of this study is to determine and asses objectively the characteristics of the ocular optical quality in patients with different stages of primary open-angle glaucoma or ocular hypertension (OHT) in reference to a healthy control group.

Setting:

Private Hospital in Barcelona.

Methods:

The design of this study is transversal observational of nonconsecutive cases. Ocular parameters were evaluated for ocular aberrations and optical quality in 42 eyes (of 23 patients) with glaucoma or ocular hypertension (OHT) (5 eyes with OHT, 23 eyes with mild POAG, 12 eyes with moderate POAG and 2 eyes with advanced POAG) and 47 eyes (of 26 patients) of the healthy control group. Patients signed an informed consent approved by the Ethics Committee of the Instituto de Microcirugía Ocular (IMO, Barcelona) where the study was conducted. POAG stages were classified according to their visual field defects. In all patients, visual acuity was determined with the best optical correction, ocular aberrations (Hartmann - Shack system) with WASCA device (Wavefront Supported Custom Ablation, Carl Zeiss Meditec) and ocular optical quality measurement using the double-pass technique with HDA instrument (High Definition Analyzer, Visiometrics) for a pupil diameter of 4mm. The variables used for the analysis of aberrations were RMS global aberrations and RMS higher order aberrations. For the results of the double- pass measurements variables were MTF cut-off, Strehl ratio and OSI (Objective Scatter Index). Visual acuity was determined with logMAR optotype ESDTRS scale.

Results:

60,87% of the patients in the study group and 69,23% in the control group were women. The median age (Mean ± standard deviation) of the study group was 63,62±14.60 years and 59.53±13,75 years for the control group, without statistically significant difference between both groups (p<0.05). The result (mean ± standard deviation) in logMAR VA obtained for the study group was 0.09±0.13, while in the control group it was 0.02±0.11. The difference between them was statistically significant (p<0.05). RMS global aberrations values of the study group were 1.24±0,78 and in the control group 1.48±1.24. The RMS high order aberrations results were 0.27±0.14 in the study group and 0.27±0.29 in the control group. In both cases, no statistically significant differences were found. The values obtained with the double-pass technique for MTF cut-off parameter in the study group were 26.23±11.21 and 32.01±11.24 in the control group(p<0,05). The Strehl ratio parameter values in the study group were 0.15±0.07 and 0.17±0.06 in the control group (p<0,05). OSI parameters results stand for the largest statistically significant difference between both groups. The OSI for the study group was 1.89±1.09 and 1.21±0.86 for the control group (p<0,01).

Conclusions:

The values obtained with the double-pass technique with HDA instrument in patients with primary open-angle glaucoma show that the ocular optical quality is affected with this condition, both clinically and statistically. The measurement of visual acuity is not altered clinically despite show statistically significant differences between both groups, which still shows that visual acuity is not a good parameter for monitoring this disease. The assessment of total or high-order ocular aberrations do not provide clinical information in these patients . The OSI parameter is very sensitive in detecting loss of ocular optical quality in these patients. Further studies to assess the ability to discern among different POAG stages are required.

Financial Interest:

One or more of the authors... research is funded, fully or partially, by a company producing, developing or supplying the product or procedure presented