Open Access Case study

Familial Primary Open Angle Glaucoma

Priyanka Patel, Prabha Sonwani, Suchita Singh

Ophthalmology Research: An International Journal, Page 16-23
DOI: 10.9734/or/2022/v16i430242

Primary open-angle glaucoma (POAG), also known as chronic simple glaucoma, is usually an inherited disease. Inheritance is considered multifunctional and polygenic. Glaucoma is the second leading cause of irreversible blindness worldwide, of which POAG is the most common. First-degree relatives of POAG patients are at increased risk. A reasonable risk for siblings is four and twice the risk of the normal population for the offspring, although the number of surveys varies. This case series of eight family members with POAG illustrates the stealth nature of POAG and the devastating vision loss it can cause as it progresses; emphasizing regular and comprehensive eye examinations during its early stage.

Open Access Short Research Article

Correlations between Quality of Vision, Higher Order Aberrations and Non-Invasive Keratographic Tear Film Break-Up Time in Pseudophakic Eyes after Uncomplicated Phacoemulsification

Johan Hutauruk, Tjahjono D. Gondhowiardjo, . Suhardjo, Muhammad Bayu Sasongko

Ophthalmology Research: An International Journal, Page 7-15
DOI: 10.9734/or/2022/v16i430240

Aims: In this study, we aimed to investigate the intercorrelations between tear film break up time, measured non-invasively using non-invasive keratographic break-up time (NIKBUT), higher order aberrations (HOA) and quality of vision (QoV) in pseudophakic patients.

Study Design: Cross-sectional.

Methods: Thirty-five pseudophakic aged patients aged 50 years or older, and 35 control phakic patients aged 17 to 23 years with corrected visual acuity of 20/20 were included in this study. All subjects underwent similar examination including QoV questionnaire, aberrometry to measure HOA, and NIKBUT. HOA was measured with the OPD-Scan/ ARK 10000 corneal analyzer (Nidek CO. Ltd), expressed as Root Mean Square (RMS) HOA and NIKBUT was assessed using non-invasive TF-Scan module Keratograph 5M (K5M), equipped with modified tear film scanning function (Oculus, Wetzlar, Germany). Statistical analysis was performed to find the correlation between NIKBUT, HOA and QoV.

Results: Patients in the pseudophakic group were significantly older (median age 66 vs. 20 years; P<0.01), had shorter NIKBUT (10.5 vs. 17.2; P<0.01), lower QoV score (1.63 vs. 0.68; P=0.04), and higher RMS HOA (0.5 vs. 0.26; P<0.01) compared to control group. NIKBUT was inversely correlated with RMS HOA (r = -0.19; p = 0.03) and RMS HOA was significantly correlated with QoV, even after adjustment for age and gender (r = -0.21; P0.04). NIKBUT <9.93s was correlated with lower QoV. The area under the curve was 0.81 (95% CI = 0.67 – 0.95, p = 0.012), and had 100% sensitivity and 61% specificity.

Conclusion: Shorter NIKBUT was correlated with greater HOA and greater HOA was correlated with lower QoV. NIKBUT value of shorter than 9.93s could potentially predict pseudophakic patients who will likely experience visual symptoms leading to decreased QoV; thus, the use of artificial tears might be beneficial.

Open Access Original Research Article

Knowledge, Attitude and Practices among Undergraduate Medical Students Regarding Surgical Correction of Refractive Errors; a Cross-sectional Study

Syedah Kanza Batool, Rabisa Batool, Kanwal Jamal, Muhammad Waqaruddin Sheroze, Muhammad Adil Ramzan, Syeda Afia Siddiqui

Ophthalmology Research: An International Journal, Page 1-6
DOI: 10.9734/or/2022/v16i430239

Aim: This study was aimed to assess the knowledge, attitude and practices regarding refractive error correction surgeries among undergraduate medical students.

Study Design: In this study cross-sectional study design was used.

Duration and Place of Study: The study was conducted amongst the undergraduate MBBS students studying at Dow Medical College, Karachi. The duration of study was seven months (August, 2019 till February, 2020).

Methods: A sample size of 189 was calculated for the study with confidence level 95% and confidence limit 5%. Data was collected through a validated self-administered questionnaire which was divided in five subsections used to gain information regarding participant’s demographics, knowledge, attitude and practices regarding refractive error surgeries. Data was analyzed using IBM SPSS V.22.

Results: In our study 189 students with a mean age of 21±1.8 years were included. Among the participants 112 (59.3%) had refractive errors. Glasses were used by majority 76 (67.9%) of participants for visual correction. Use of refractive error correction methods at all times was reported by 72 (66.7%) participants. Majority of respondents 142 (75.5%) had heard about surgery being used for correction of refractive errors. A large number of students 117 (66%) refused for surgery and fear of the outcomes was one of the reason for this refusal.

Conclusion: We found that majority of the participants were aware about refractive error correction surgeries yet most of them showed unwillingness for these procedures. This negative attitude must be changed to positive in order to enhance the practice for these procedures.

Open Access Original Research Article

Efficacy Theory and Proposed Protocol for Presbyopia Correction using Scleral Softening by Non-invasive Infrared Diode Lasers

Jui-Teng Lin

Ophthalmology Research: An International Journal, Page 24-36
DOI: 10.9734/or/2022/v16i430243

Purpose: To derive and provide analytic formulas and proposed protocol for accommodative gain of presbyopia eyes via laser scleral softening, which causes increased space between ciliary body and lens (SCL) and mobility of the posterior vitreal zonules (PVZ).

Study Design: To increase the accommodation of presbyopia by laser scleral heating/softening.

Place and Duration of Study: New Taipei City, Taiwan, between April 2022 and June 2022.

Purpose: To analyze the safety and efficacy of presbyopia treatment via scleral softening.

Methodology: The scleral softening efficacy is calculated based on the rate equation of scleral tissue with a rate coefficient given by an Arrhenius formula, Temperature spatial and temporal profiles are given by the numerical solutions of a heat diffusion equation with a volume heating source. Various effective depths including tissue damage depth, temperature penetration depth and conversion depth, governed by tissue absorption coefficient, light intensity and dose (or irradiation time), and the related threshold values, are introduced in replacing the conventional penetration depth based on a Beer's law.

Results: Given the the temperature spatial and temporal profiles, scleral softening efficacy can be calculated. Scleral surface damage can be prevented by cooling window. The suggested protocol for scleral softening treatments include: a diode laser at about 1.45 to 1.5 µm or about 1.86 to1.9 µm, or about 2.0 to 2.15 µm, wavelength (with absorption coefficient about 20 to 100 cm-1); laser power about 0.2 to 0.8 W per spot, having a total of 4 to 16 spots; and irradiation time of 100 to 600 ms. Results of corneal thermal shrinkage are demonstrated by the topography changes of pig eyes, in which the scleral softening does not affect the corneal shapes. The accommodative gain is proportional to the softening efficacy (Seff) of the scleral tissue after a thermal laser leading to the increase of PVZ mobility and SCL. However, the actual relation of Seff and the PVZ and SCL changes require measured data.

Conclusion: Safety and efficacy of scleral softening for presbyopia treatment depend upon the laser parameters (intensity, dose, spot size, wavelength) and the effective depths. By choosing the laser treated areas, a dual function treatment using scleral softening for presbyopia, and cornea stromal shrinkage for hyperopia is proposed and demonstrated by topography of pig eyes.

Open Access Original Research Article

Accommodative Gain in Presbyopic Eye Using a New Procedure of Laser Scleral Softening (LSS): Part-II. Formulas for Volume Efficacy

Jui-Teng Lin

Ophthalmology Research: An International Journal, Page 37-46
DOI: 10.9734/or/2022/v16i430244

Purpose: To derive and provide, for the first time, comprehensive analytic formulas for scleral softening volume efficacy (SVE) for accommodative gain (AG) via the increased space between ciliary body and lens (SCL) and mobility of the posterior vitreous zonules (PVZ).

Study Design: To increase the AG of presbyopic eye by a new procedure, laser scleral softening (LSS).

Place and Duration of Study: New Taipei City, Taiwan, between June 2022 and July 2022.

Methodology: The SVE is calculated based on the time and spatial integral of the scleral temperature profiles, T(z,t), solutions of a heat diffusion equation. Analytic formulas for SVE is derived based on the covered area given by a triangle area. The SVE of a 3-D model is governed by the "volume" covered by the laser beam, or its spot size area, the effective penetration depth (z"), which is an increasing function of laser dose, but a decreasing function of the absorption coefficient (A), due to the Beer's law of laser intensity, I(z)=I0exp(-Az). The efficacy depth-range (dZ) and time-ranges (dT) are defined for efficient softening with T(z,t)>T*, where T* is the scleral softening threshold temperature.

Results: The accommodative gain is proportional to the 3-D SVE given by: SEV(3D) = SEV(1D) x laser beam spot (2-D area) x total number of spots (N) acting on the sclera, which is proportional to the efficacy ranges dZ and dT, in which dZ is an increasing of laser irradiation time, whereas dT is a decreasing function of depth. Softening of the scleral tissue after a thermal laser leading to the increase of PVZ mobility and SCL. However, the actual relation of SVE and the PVZ and SCL changes require measured data.

Conclusion: Safety and efficacy of scleral softening for presbyopia treatment depend upon the laser parameters (intensity, dose, spot size, wavelength) and the effective depths. The SVE is proportional to the efficacy depth-range (dZ) and time-range (dT), in which dZ is an increasing of laser irradiation time and dT is a decreasing function of depth. The AG is proportional to the SVE(in 3-D).